Unit IV

Part-A: Introduction to Mechanical Engineering

Short answer questions:
1. What is the role of Mechanical Engineer in Society?
Ans: Mechanical engineers develop Farm machinery, Automobiles, Medical devices like artificial
joints, pacemakers, and dialysis machines.
2. Label the role of mechanical engineering in industries.
Ans: Mechanical Engineers are involved in designing, building, and maintaining the
engines, machines, and structures that make modern life possible and comfortable.
3. What is HVAC?
Ans: HVAC stands for heating, ventilation, and air conditioning. HVAC cares about the need to
provide thermal comfort and acceptable indoor air quality within reasonable installation, operation,
and maintenance costs.
4. Differentiate renewable and non-renewable energy.
Ans: Renewable energy is energy derived from natural sources that are replenished at a higher rate
than they are consumed. Examples are Sunlight and wind. Non-renewable energy is a source of
energy that will eventually run out. Examples are fossil fuels, such as coal, gas, and oil.
5. Name different types of non-renewable energy sources.
Ans: Coal, Natural gas, Diesel and petrol, Nuclear fuel
6. Name any Four renewable energy sources.
Ans: Solar, wind, geothermal, Tidal energy are renewable energy sources.
7. What is Industry 4.0?
Ans: Industry 4.0 can be defined as the integration of intelligent digital technologies into
manufacturing and industrial processes. It encompasses a set of technologies that include industrial
IoT networks, AI, Big Data, robotics, and automation.
8. Define 3D printing and additive manufacturing.
Ans: 3D printing, or additive manufacturing, is a computer-controlled process in which
three-dimensional objects can be created by materials deposited in layers.
9. What is the role of Machine vision in Automotive Industry.
Ans: Automotive was one of the earliest industries to have adopted Machine Vision to
carry out its imaging-based automatic inspection and analysis for automatic inspection,
process control, and robot guidance.
10. What is the role of Artificial Intelligence in Automotive sector?
Artificial intelligence in cars first creates and stores an internal map of the surroundings
(street, locality, or region) using smart sensors such as radar, sonar, and/or laser. It then
processes these inputs, plots the most plausible trajectory, and sends instructions to the
vehicle’s actuators, which control acceleration, braking, and steering.
11. How Material science plays a crucial role in Aerospace industry?
Ans: New high-performance metallic and non-metallic materials are being developed for
the requirements of future products, such as advanced lightweight alloys, high-
temperature materials, coatings, multifunctional composites for the needs of aerospace
industry to reduce weight and provide superior physical and chemical properties.

12. What are the advanced technologies used in Propulsion of aerospace sector?
Ans: Competitive alternatives to current engines are being investigated, such as electrically
powered propulsion devices based on plasma generation for satellites and the developing of
reusable engines for launchers.
13. Explain maritime robotic solutions.
Ans: Lack of workers and their safety in marine environments are growing concerns in
the maritime sector. Robots that assist in logistics operations, robots tailored for
maritime maintenance, cleaning, rescue, and inspection.
14. List the mechanical engineer work on marine sectors.
Ans: Mechanical engineers develops energy-efficient systems to minimize Green House Gas
(GHG) emissions and fuel costs. predictive maintenance, autonomous navigation, and route
optimization.in marine sector also taken care by Mechanical engineers.

Descriptive Question:
1. What are the contributions of mechanical engineering to society and industry?
Mechanical engineers are involved in almost every aspect of human existence and
welfare, including machines, cars and other vehicles, aircraft, power plants, automobile
parts, manufacturing plants, etc.
A Mechanical Engineer plays a significant role in designing, developing, manufacturing
and testing machines and thermal devices.
Mechanical engineers will also provide their services in maintaining machinery,
equipment and repairing during its life period.

Contribution of Mechanical Engineering to the society

Role of Mechanical Engineering in Society:
1. Transportation:
a. Designing and manufacturing vehicles: Mechanical engineers design cars, trains,
ships, andairplanes, ensuring they are safe, efficient, and comfortable.
For example, the development of electric vehicles (EVs) involves mechanical
engineeringexpertise in
 Battery Technology,
 Aerodynamics,
 Lightweight Materials.
 b. Improving fuel efficiency: Mechanical engineers work on engine design and
optimization to enhance fuel efficiency and reduce emissions, contributing to
environmental sustainability.
2. Energy Production and Conservation:
a. Designing renewable energy systems: Mechanical engineers develop technologies
for connecting renewable energy sources such as solar panels, wind turbines, and
hydroelectric generators.
b. Energy conservation: Mechanical engineers design energy-efficient HVAC systems,
insulation materials, and smart appliances to reduce energy consumption in
buildings and industries.
3. Healthcare:
a. Medical device design: Mechanical engineers design and develop medical devices
such as prosthetics, artificial organs, surgical instruments, and diagnostic equipment.
b. Biomechanics: Mechanical engineers apply principles of mechanics to understand
how the human body moves and functions, contributing to the design of ergonomic
equipment and treatment devices.
4. Infrastructure Development:
a. Civil engineering support: Mechanical engineers contribute to the design and
construction of infrastructure projects such as bridges, tunnels, dams, and roads by
providing expertise in structural analysis, materials science, and construction
techniques.
b. Disaster relief: Mechanical engineers design and deploy emergency shelters, water
purification systems, and disaster response vehicles to assist in disaster relief efforts.
5. Manufacturing and Industry:
a. Process optimization: Mechanical engineers improve manufacturing processes by
optimizing production lines, implementing automation, and enhancing quality
control measures.
b. Industrial machinery: Mechanical engineers design and maintain machinery used in
manufacturing, mining, agriculture, and construction sectors, ensuring efficiency and
reliability.
6. Consumer Products:
a. Product design: Mechanical engineers contribute to the design and
development of
consumer products such as smartphones, household appliances, and sports equipment.
b. Ergonomics: Mechanical engineers consider human factors and ergonomics when
designing products to ensure user comfort, safety, and usability.
7. Environmental Conservation:
a. Waste management: Mechanical engineers develop technologies for recycling and
 waste management to minimize environmental impact.
b. Pollution control: Mechanical engineers design systems for air and water pollution
control, such as scrubbers, filters, and wastewater treatment plants.
 Mechanical engineering provides better transport facilities to society
 Many benefits to society due to the country's economic improvement, industrial development.
 Increased employment opportunities in industries and power stations.
 Mechanical engineering plays a vital role in society by addressing pressing challenges,
improvingquality of life, and driving technological advancements across various sectors.

 Farm machinery are designed and developed to improve the agricultural yield with
the work comfort and ease in operation.

 Medical devices like artificial joints, pacemakers, and dialysis machines have been designed
and manufactured by mechanical engineers.
Overall, Mechanical Engineers are involved in designing, building, and maintaining the
engines, machines, and structures that make modern life possible and comfortable. They
contribute to society by using their skills to improve the safety, security, efficiency, and
comfort of the systems and devices we rely on daily.

2. What is mechanical engineering? Explain the role of mechanical engineering in industries.

Mechanical engineering is a branch of engineering which deals design, analysis, testing,
manufacturing and maintenance of mechanical systems.

Mechanical engineering plays a crucial role in various industries by applying the principles of
Engineering and material science to design, analyze, manufacture, and maintain mechanical systems.
Here are some key points showing its significance.
1. Design and Development
2. Manufacturing Processes
3. Energy Systems and Sustainability
4. Transportation
5. Automation and Robotics
6. Aerospace and Defense
7. Materials Selection and Processing
8. Quality Control and Assurance
9. Heating, Ventilation & Air Conditioning (HVAC)
10. Infrastructure Development

1. Product Design and Development and Society:

 Mechanical engineers : They utilize their knowledge of mechanics, materials, and
manufacturing processes to create innovative solutions.
 They involved in the design and development of a wide range of products,
  Consumer goods like smartphones and automobiles
 Industrial goods like machinery, conveyor systems & belts.
 In the automotive industry, components such as engines,
chassis,and transmissions, ensuring they meet performance, safety, and
efficiency standards.
 They ensure that these products are efficient, reliable, and safe for use.
 They utilize CAD (Computer-Aided Design) and other software to create detailed
schematics andmodels, ensuring the functionality, efficiency, and safety of the designs.
Example:
 Designing fuel-efficient engines for automobiles
 Developing advanced robotics for manufacturing processes.

2. Manufacturing Processes:
 They apply principles of mechanics, thermodynamics, and materials science to
streamlineproduction.

 Mechanical engineers optimize processes such as machining, casting, welding and

additivemanufacturing processes,
 To enhance efficiency
 To reduce costs and improve cost effectiveness
 To improve product quality
 To improve Productivity
 Their knowledge in automation and robotics leads to advancements in
manufacturingtechnologies.
Example: Implementing automation and robotics in assembly lines to streamline
production.
3. Energy Systems and Sustainability:
 Mechanical engineers play a vital role in the development of alternative energy systems,
including,
 Renewable energy sources such as wind, solar, and hydroelectric power.
 They also work on improving the efficiency of traditional energy systems like
 Combustion engines
 Power plants.
 Gas turbines,
 Steam and wind turbines
 Mechanical engineers contribute significantly to the energy sector by
 Designing power plants,
 Designing renewable energy systems,
 Designing energy-efficient machinery.
  They work on improving the performance of engines, turbines, and HVAC systems
 They work on to reduce energy consumption and environmental impact.
Example: Designing wind turbines or solar panels to harness renewable energy for power
generation.
4. Transportation:
 Mechanical engineers are involved in the design and maintenance of various
transportationsystems, including
 Automobiles,
 Trains,
 Ships,
 Aircraft.

 Mechanical engineers work on,

 Improving fuel efficiency,
 Reducing Emissions,
 Enhancing safety in transportation vehicles.
 They focus on enhancing safety, performance, and fuel efficiency in automobiles, trains,
airplanes, and ships.
Example: Designing lightweight materials for aircraft to reduce fuel consumption or
developingelectric vehicles for eco-friendly transportation.
5. Automation & Robotics:
 Mechanical engineers design and integrate robotic systems and automation solutions,
controlsystems to enhance productivity and safety in manufacturing environments.
 They develop control algorithms for autonomous machines.
 They develop sensor technologies for autonomous machines.
 They reduce manual labor.
Example: In the automotive assembly line, mechanical engineers arrange industrial robots to
perform repetitive tasks such as welding, painting, and assembly, increasing efficiency and
worker safety.
6. Aerospace and Defense:
 Mechanical engineers play a vital role in the aerospace and defense sectors by Designing,
 Designing of Aircraft,
 Designing of Spacecraft,
 Designing of Missiles,
 Designing of Defense Systems.
 They work on aerodynamics, structural analysis, and propulsion systems to ensure the
reliability and efficiency of aerospace technologies.
 Innovations in materials and manufacturing processes are critical for advancing
 aerospacecapabilities.
Example: Designing aircraft engines for improved performance and efficiency
Developing missile guidance systems for defense applications.
7. Materials Selection and Processing:
 Mechanical engineers work on developing new materials and improving existing ones
to meetthe specific requirements of different industries.
Example: Researching and developing lightweight and high-strength materials for use in
automotiveand aerospace industries.

8. Quality Control and Assurance:

 Mechanical engineers establish quality control procedures to ensure products meet
industry
standards and regulatory requirements.
 They use inspection techniques and statistical analysis to identify and resolve defects.
Example: Testing procedure to confirm the size and defect of the product through various
inspectionmethod of Non destructive testing methods like Liquid Penetrant test.
9. HVAC and Building Systems:
 Mechanical engineers design heating, ventilation, and air conditioning (HVAC)
systemsto ensure comfortable and energy-efficient indoor environments.
Example: Designing HVAC systems for commercial buildings to optimize energy usage
andmaintain indoor air quality.
10. Infrastructure Development:
 Mechanical engineers contribute to the design and construction of infrastructure projects
such as
 Bridges,
 Dams,
 High Rise Buildings.
 They ensure that these structures are structurally sound,
 They ensure that these structures are resilient to environmental factors, and cost-effective.
These contributions are essential for addressing global challenges and improving the quality of life
for peoplearound the world.

3. Explain how non-renewable energy technologies meet the energy demand.

Energy technology is an interdisciplinary engineering science about the

 Efficiency,
 Safety,
 Environmentally Friendly
 Economical Extraction & Conversion,
  Storage & Transportation,
 Energy Usage.
Energy technology targeted towards,
 Yielding high efficiency by Energy
 Reducing side effects by Energy on humans, nature, and the
environment.
 The gathering and using of energy resources can harm local ecosystems and may have
globaloutcomes. Energy is the capacity to do work. Humans get energy from food.
 In general, Energy can be of different forms, such as kinetic, potential, mechanical, heat, light,
etc.
 Energy is required by individuals and society for lighting, heating, cooking, running
industries,operating transportation, and so forth.
There are two types of energy depending on the sources they are:
1. Renewable Energy Sources (Derived from replenishable sources)
2. Non-Renewable Energy Sources. (Derived from finite sources)
1. Renewable Resources Include:
i. Solar Energy
ii. Wind Energy
iii. Hydropower (Falling Water)
iv. Biomass (Plant Materials)
v. Geothermal Energy (The Earth's Heat)
vi. Tidal Energy (Energy of The Tides)
vii. Ocean Thermal Energy (Temperature Differences In The Oceans)
2. Non-Renewable Resources:
Fossil fuels are formed from the decomposition of buried carbon-based organisms that died
millions of years ago. They are extracted and burned for energy. `
a. Oil,
b. Natural Gas,
c. Coal,
d. Nuclear Energy.

1. Renewable Energy Technologies:

a. Solar Power:
i. Photovoltaic (PV) cells: Convert sunlight directly into electricity.
 Example: Solar panels installed on rooftops or in solar farms.
ii. Concentrated Solar Power (CSP): Uses mirrors or lenses to concentrate
sunlightonto a small area, generating heat to produce electricity.
 Example: Solar thermal power plants.
b. Wind Power:
  Wind turbines: Convert wind energy into electricity through the rotation of
turbineblades.
 Example: Wind farms installed on land or offshore.
c. Hydroelectric Power:
 Hydroelectric dams: Capture the energy of flowing water to
generate electricity.
 Example: Large-scale hydroelectric dams such as the
Hoover Dam.
d. Biomass:
 Biomass combustion: Burns organic materials such as wood,
agriculturalresidues, or biogas to produce heat or electricity.
 Example: Biomass power plants.
2. Non Renewable Energy Technologies:
Non-renewable energy refers to energy sources that are finite in nature and cannot be
replenished on a human timescale. These energy sources are typically derived from fossil fuels and
nuclear materials.
All these are used for
 Electricity Generation,
 Heating,
 As a Fuel for Vehicles,
 Transportation
 Industrial Processes.
a. Coal: Coal is a combustible sedimentary rock that is mined for its energy content.
 Example: Coal-fired power plants supply a significant portion of the
world'selectricity.
b. Oil: Also known as petroleum, oil is a liquid fossil fuel extracted from
underground
reservoirs. It is refined into various products such as gasoline and diesel
 Example: Gasoline used in cars and trucks is derived from petroleum.
c. Natural Gas: Natural gas is a mixture of hydrocarbon gases, primarily methane,
foundin underground deposits.
 Example: Natural gas-fired power plants provide electricity in time of high
demand.

d. Nuclear Energy:
 Nuclear energy is generated through nuclear fission, where the nucleus of an
atom issplit into smaller parts, releasing large amounts of energy.
 Example: Nuclear power plants, Uranium and plutonium undergoes
fission reactions in nuclear reactors to produce heat, which is then converted
 into electricity.
Energy Storage Technologies:
 Energy storage technologies such as
 Lithium-Ion Batteries,
 Pumped Hydro Storage,
 Compressed Air Energy Storage,
 Smart grid technologies (Monitor & control) All these enable efficient
management and distribution of electricity.
Energy Efficiency Technologies:
 Energy efficiency technologies such as
 LED Lighting,
 Energy-Efficient HVAC Systems,
 Building insulation
All these contribute to reducing greenhouse gas emissions, enhancing energy security, and
promoting economic development in transitioning towards a sustainable energy system.

4. Explain various technologies used in manufacturing to produce quality products.

 There are many modern manufacturing technologies, most of them specifically relevant to
„Industry 4.0‟, the name given to the fourth industrial revolution, associated with automation,
data exchange, digital technology, artificial intelligence and machine learning, and the
„Internet of Things‟. Therefore, many manufacturing technologies innovating production and
industry are also relevant to this fourth wave of technological advancement. Few are as given
below,
1. Smart Factories
2. Cyber-Physical Systems
3. Additive Manufacturing
4. Big Data
5. Numerical Control
6. Computer-Aided Design (CAD):
7. Computer-Aided Manufacturing (CAM)
8. Robotics and Automation:
9. Advanced Materials and Composites

1. Smart Factories:
 Integration of advanced technologies and automation to create interconnected
manufacturing systems.
  Smart factories are highly digitized environments that occur more efficiently
through connected systems. Through innovative manufacturing technology like
automation, self optimization, the machines and systems can learn and adapt to
situations with increased productivity.
 Able to produce goods on a large scale, smart factories are useful for
manufacturing jobs and processes like planning, supply chain logistics, and
product development.
 Example: Smart sensors, IoT platforms, real-time data analytics.
 Applications: Predictive maintenance, optimized production scheduling.
2. Cyber-Physical Systems:
 Integration of computer, networking, & physical processes to monitor and
control manufacturing systems.
 In this, embedded computing technologies control and monitor processes in real-
time.
 The computer system monitors the process and identifies areas where change is
required, and the physical system reacts accordingly.
 Example: Cyber-physical production systems (CPPS), digital twins.
 Applications: Remote monitoring, real-time adjustments, autonomous production.
3. Additive Manufacturing & 3D Printing:
 Builds objects layer by layer from digital designs, enabling complex
geometries and rapid prototyping.
 3D printing or additive manufacturing, is a computer-controlled process in
which three-dimensional objects can be created by materials deposited in
layers.
 By using Computer-aided design (CAD) & 3D object scanners, the
components, parts, or any other object can be made without machining or
other techniques and,therefore, less surplus of material.
 Example: Selective Laser Sintering (SLS), Fused Deposition Modeling (FDM).
 Applications: Prototyping, customized products, medical implants.
4. Big Data:

 Collection, analysis, and utilization of large volumes of data to optimize

manufacturing processes.
 Data‟s are collected constantly in systems, sensors, and common place electronic
items like mobile devices, and the amount of data to be stored is growing daily.
 „Big data‟, a collection of global data from various sources, which can be useful in
manufacturing technology. The industry is in the process of developing methods to
interpret and analyze data to use in production.
 5. Numerical Control:
 Automation of machine tools through programmed commands to achieve
precise and repeatable manufacturing operations.
 Machining tools or manufacturing items like 3D printers can be regulated and
controlled remotely using CNC-computer numerical control.
 A Modern CNC machine processes a piece of material to key specifications,
following a coded programmed instruction with highly automated & without a
manualoperator to create products efficiently and remotely.
 Example: Computer Numerical Control (CNC) machines.
 Applications: Machining, milling, turning, drilling, Laser cutting and additive
manufacturing

The additional technologies further enhance the capabilities of modern manufacturing, enabling
greater efficiency, flexibility and innovation in production processes are..

6. Computer-Aided Design (CAD):

 A Software for designing products or systems. CAD software enables
engineers to create detailed 2D and 3D models of products and components.
 Example: AutoCAD, SolidWorks, CATIA.
 Applications: Designing machinery, vehicles, consumer products &
industrialequipment.
7. Computer-Aided Manufacturing (CAM):
 A Software for controlling manufacturing processes. CAM software
translates CADmodels into instructions for automated machinery and tools.
 Example: CNC (Computer Numerical Control) machines, 3D printers.
 Applications: CNC machining, additive manufacturing, robotic assembly.
8. Robotics and Automation:
 Robots perform repetitive or dangerous tasks with precision and consistency.
 Example: Robotic arms, automated guided vehicles (AGVs).
 Applications: Assembly lines, material handling, welding, painting.
9. Advanced Materials and Composites:
 Lightweight and high-strength materials improve performance and efficiency.
 Example: Carbon fiber, graphene, titanium alloys.
 Applications: Aerospace components, automotive parts, sporting goods.
5. Explain the mechanical engineer work on automotive sectors.

 Ans Industrial automation is spreading through most industries these days. It wouldn‟t be
surprising if much of the industrial intelligentsia have already started in on looking into the
prospects of precision agriculture, smart
 manufacturing, or digital medicine. And these industries, including automotive, aren‟t
beginner to automation technologies such as Artificial Intelligence (AI) or Machine Learning.
 Some most advanced automation technologies used in the automotive industries are :
1. Machine Vision
2. Collaborative Robots
3. Artificial Intelligence for Driverless/Autonomous Cars
4. Internal Combustion Engine (ICE)
5. Electric Vehicles (EV)
6. Hybrid Vehicles
7. Autonomous Vehicles (AVs)
8. Advanced Driver Assistance Systems (ADAS)
9. Lightweight Materials
1. Machine Vision:
 Safer, reliable & robust automobiles pushing automakers to adopt new inspection
method.
 Technology that enables machines to "see" & interpret visual information is
“MachineVision”.
 Machine Vision (MV) helps them fulfil these need by providing an automated
internalmachine inspection method.
 Machine vision systems use cameras, sensors, and algorithms to analyze
images and
identify objects, defects, and patterns.
 In Automotives, MV to carry out by,
 Imaging-based automatic inspection analysis,
 Process control and robot guidance.
 MV works as the eye of the automotive production process using imaging processes
of,
 Conventional Imaging,
 Infrared Imaging,
 Line Scan Imaging,
 3D Imaging of Surface
 Smart cameras / smart sensors are used along with interfaces such as
 Camera Link to record / capture images of the surface to be inspected.
 Cameras to CPU connectors via FireWire, USB, Gigabit Ethernet
 interfaces.
 These cameras capture images of the surface of the automobile component are
inspected (say,the body or fins of an engine).
 And these images are then processed / analysed by analysis software‟s.
 Example: Camera-based lane departure warning systems, automated quality
controlinspection in manufacturing.
 Applications: Personalized infotainment, proactive vehicle maintenance,
intelligentnavigation.
2. Collaborative Robots (Cobots):
 Generally called Cobots, Cobots are the Robots designed to work together with
humans inshared workspaces.
 Cobots are equipped with sensors and safety features to interact safely with human
operatorsand assist in various tasks.
 Cobot uses machine learning to pause all its operations when a worker enters its
space.
 When a certain job requires multiple functions at once, the Collaborative Robots
(Cobots)
will allow the worker to work on it along with robot.
 Using Cobots in such settings can put carmakers light-years ahead in the race for
speed andproductivity in manufacturing.

 Example: Assembly line robots that collaborate with human workers, robotic
exoskeletons for ergonomics. Tesla to build cars, car-building robots, and assembly
lines.
 Applications: Manufacturing, logistics, healthcare, automotive assembly.
3. Artificial Intelligence for Driverless/Autonomous Cars
 AI algorithms and machine learning techniques used to enable autonomous vehicles to
perceive and navigate their environment.
 AI algorithms process data from sensors such as cameras and radar to make real-time
drivingdecisions.
 Artificial Intelligence is “any system that understands its environment and takes
actions thatmaximize its chance of success to the aimed goal.”
 Artificial intelligence in cars, first creates and stores an internal map of the
surroundings
(street, locality, or region) using smart sensors such as
 Radar (Radio Detection & Ranging)
 Lidar (Light Detection and Ranging)
 Sonar (Sound Navigation & ranging)
 It then processes these inputs & plots to the vehicle‟s actuators, which control
acceleration,braking and clutch / steering.
  Few AI System tools that helps the car to follow traffic rules and navigate past obstacles
are,
 Coded driving protocols,
 Obstacle avoidance algorithms,
 Predictive modelling,
 Smart object discrimination (i.e., knowing the difference between a
bicycleand a motorcycle)

 Example: Deep learning algorithms for object detection and classification,

reinforcement learning for path planning. Driverless car hardware (Autopilot) used
on all Tesla models.
 Applications: Autonomous driving systems, self-parking features, adaptive cruise
control.
4. Internal Combustion Engine (ICE):
 An engine that burns fuel inside cylinders to generate power. ICEs are commonly
used intraditional vehicles, running on gasoline or diesel fuel.
 Example: Gasoline engines, diesel engines.
 Applications: Cars, trucks, motorcycles, buses.
5. Electric Vehicles (EV):
 Vehicles powered by electric motors and batteries rather than internal combustion
engines.
 EV’s popularity due to their environmental benefits & advancements in battery
technology.
 Example: Battery Electric Vehicles (BEVs), Plug-in Hybrid Electric Vehicles (PHEVs).
 Applications: Passenger cars, commercial vehicles, public transportation.
6. Hybrid Vehicles:
 Vehicles that combine an internal combustion engine with an electric motor and battery.
 Hybrid vehicles offer improved fuel efficiency and reduced emissions by
utilizing bothgasoline and electric power.
 Example: Hybrid electric cars, hybrid electric buses.
 Applications: Consumer vehicles, fleet vehicles, taxis.
7. Autonomous Vehicles (AVs):
 Vehicles capable of sensing and navigating their environment without human input.
 AVs use various sensors, cameras, and artificial intelligence algorithms to
perceive andrespond to their surroundings.
 Example: Self-driving cars, autonomous shuttles.
 Applications: Ride-sharing services, public transportation, delivery vehicles.
8. Advanced Driver Assistance Systems (ADAS):
 Technologies that assist drivers in controlling the vehicle and avoiding accidents.
 ADAS features include
  Adaptive Cruise Control,
 Lane Departure Warning,
 Automatic Emergency Braking.
 Example: Adaptive cruise control, blind-spot monitoring, parking assistance.
 Applications: Passenger cars, commercial trucks, fleet vehicles.
9. Lightweight Materials:
 Materials that offer high strength-to-weight ratios, reducing vehicle weight and
improvingfuel efficiency.
 Lightweight materials such as aluminum, carbon fiber, and advanced composites
are usedin vehicle construction.
 Example: Aluminum alloy body panels, carbon fiber reinforced plastic (CFRP)
components.
 Applications: Body structures, chassis components, interior trim.

6. List out the technologies used by the aerospace industry.

The aerospace industry has constantly evolved hand in hand with technological developments,
allowing it to improve its competitiveness and research capacity while acting as a driving force for
progress in other disciplines. Some of the key areas are..
1. Technologies related to propulsion and aerodynamics in rockets and satellites.
2. Life support and protection systems associated with exploration missions.
3. Materials science.
4. Aircraft Design and Analysis
5. Aerodynamics
6. Avionics and Flight Control Systems
7. Unmanned Aerial Vehicles (UAVs)

1. Technologies related to Propulsion and Aerodynamics in Rockets and Satellites:

 Propulsion systems and aerodynamic designs specific to rockets and satellites for
spaceexploration.
 These technologies include
 Rocket engines,
 Thrusters,
 Aerodynamic shapes optimized for space travel and satellite orbits.
 Electrically powered propulsion devices based on plasma generation for
satellites
 Developing of reusable engines for launchers.
 Example: Liquid rocket engines (SpaceX Merlin engines).
 Applications: Launch vehicles, spacecraft propulsion, satellite deployment.
2. Life Support and Protection Systems associated with Exploration Missions:
  Systems designed to give,
 Sustain human life & protect astronauts during space exploration.
 Life support systems provide oxygen, water, and temperature regulation,
whileprotection systems shield against radiation and micrometeoroids.
 Evaporative cooling to maintain appropriate temperatures in space suits.
 Example: Environmental control & life support systems (ECLSS), radiation
shieldingmaterials.
 Applications: Human spaceflight missions, space station habitats, lunar / Mars
exploration.
3. Materials Science:
 The selection and engineering of materials for aircraft construction to meet
performance and safety requirements, strength, durability and weight-saving properties
by including
 Lightweight Composites,
 Heat-Resistant Alloys
 High-Temperature Materials
 Radiation-Hardened Materials.
 Materials science plays a crucial role in spacecraft construction, ensuring
 Structural integrity,
 Thermal protection,
 Performance in harsh space environments.
 Example: Carbon-carbon composites, nickel-based superalloys, Kapton film.
 Applications: Spacecraft structures, thermal protection systems, spacecraft
components.
4. Aircraft Design and Analysis:
 The process of designing, analyzing, and optimizing aircraft structures and systems.
 Aerospace engineers use computer-aided design (CAD) software and simulation
tools todevelop aerodynamic shapes, structural components, and propulsion systems.
 Example: Boeing 787 Dreamliner, Airbus A350 XWB.
 Applications: Commercial aircraft, military aircraft, unmanned aerial vehicles (UAVs).
5. Aerodynamics:
 The study of airflow around objects and its effects on flight performance.
 Aerodynamic principles are applied to design aircraft wings, fuselage shapes, and
controlsurfaces for optimal lift, drag, and stability.
 Example: Airfoil shapes, winglets, vortex generators.
 Applications: Wing design, aircraft performance optimization, wind tunnel testing.
6. Avionics and Flight Control Systems:
 Electronic systems that control aircraft navigation, communication, and flight
operations.
  Avionics include instruments, sensors, and computer systems that monitor and
manageaircraft functions, such as autopilot and fly-by-wire systems.
 Example: Flight management systems (FMS), inertial navigation systems (INS),
electronicflight displays.
 Applications: Navigation, communication, autopilot, flight management.
7. Unmanned Aerial Vehicles (UAVs):
 Aircraft operated without a human pilot onboard, controlled remotely or autonomously.
 UAVs are used for military reconnaissance, surveillance, aerial mapping, and
civilian applications such as agriculture, infrastructure inspection, and parcel
delivery.
 Example: General Atomics MQ-9 Reaper, DJI Phantom drones.
 Applications: Military operations, aerial photography, disaster response.
These technologies are vital for the success of space exploration missions, enabling
propulsion, life support, scientific research, and spacecraft construction in the challenging
environment of space.

7. Explain the mechanical engineer work on marine sectors.

(or)
8. Explain how AI, clean energy, and energy-efficient integrations help the marine sector ?
Technologies in Marine Sectors:
1. Artificial Intelligence
2. Clean Energy
3. Maritime Robotics
4. Energy-Efficient Integrations
5. Ship Design and Naval Architecture
6. Marine Propulsion Systems
7. Hydrodynamics and Fluid Mechanics
8. Marine Materials and Corrosion Protection
9. Navigation and Positioning Systems

1. Artificial Intelligence (AI):

 The simulation of human intelligence processes by machines, including learning,
reasoning,and problem-solving.

 AI is used in automotive applications for autonomous driving, predictive

maintenance, andpersonalized user experiences.
 The maritime sector deploys artificial intelligence for various applications such as
 Predictive maintenance,
 Autonomous navigation, and route optimization.
 o The critical role of AI in these functions is to process the vast data available
through sensors, public information systems, and asset tracking to generate
actionable insights.
 The processed information to improve
 Forecasting accuracy
 Optimize fuel efficiency,
 Maintenance, and operational costs.
 AI in underwater robots and vehicles facilitates
 Search and rescue operations
 Assists in underwater repairs.
 Ports, ships, and fleets using AI to monitor their operations continuously, improving
vesseland port management.
 Example: Self-driving car algorithms, natural language processing for voice
commands,predictive analytics for vehicle health monitoring.
 Applications: Autonomous vehicles, virtual assistants, predictive maintenance systems.
2. Clean Energy:
 Energy derived from renewable sources with minimal environmental impact, such
as solar,wind, and hydrogen.
 Clean energy technologies in automotive include electric vehicles (EVs), fuel cell
vehicles,and sustainable manufacturing practices.
 Marine heavy fuel oil (HFO), a petroleum-based product, is the most common
propulsion fuel in ships, accounting for many of the emissions from maritime
operations.
 Like other industries, transitioning to low-carbon, renewable energy sources is
crucialfor maritime decarbonization.
 For this, the industry is looking up to
 electric propulsion technologies,
 biofuels, wind energy, solar power, and hydrogen fuel.
 Many startups already offer retrofittable devices to electrify boats.
 Example: Electric cars powered by renewable energy sources, hydrogen fuel cell
vehicles.
 Applications: Transportation electrification, decarbonization of the automotive
industry,renewable energy integration in manufacturing.

3. Maritime Robotics:
 Autonomous robotic systems designed for maritime applications, including navigation,
inspection, and environmental monitoring.
 Maritime robots are used for tasks such as
 Underwater Exploration,
  Oceanographic Research,
 Offshore Infrastructure Inspection.
 To tackle safety in marine environments, startups are building maritime robotics
solutions with AI and advanced hardware.
 Robots tailored for
 Maritime maintenance,
 Cleaning,
 Rescue, and inspection
 Underwater maintenance tasks.
 Example: Autonomous underwater vehicles (AUVs), remotely operated vehicles
(ROVs),unmanned surface vessels (USVs).
 Applications: Underwater surveys, pipeline inspection, marine biodiversity monitoring.
4. Energy-Efficient Integrations:
 Integration of energy-efficient technologies and practices to reduce emissions &
fuelconsumption and environmental impact in automotive operations.
 Energy-efficient integrations include lightweight materials, aerodynamic designs,
andregenerative braking systems.
 This entails improvements of various systems in the vessel, from scrubber and
rudder tolubrication, coatings, and propulsion systems.
 Example: Lightweight vehicle structures, aerodynamically optimized body
shapes,regenerative braking systems.
 Applications: Fuel efficiency improvements, emissions reduction, sustainable
manufacturingprocesses.
5. Ship Design and Naval Architecture:
 The design and engineering of ships and marine structures.
 Naval architects use principles of hydrodynamics, structural engineering, and
marinepropulsion to design vessels optimized for performance, stability, and safety.
 Example: Container ships, cruise liners, offshore oil platforms.
 Applications: Commercial shipping, naval vessels, offshore exploration.
6. Marine Propulsion Systems:
 Systems that provide thrust to propel ships through water.
 Marine propulsion technologies include diesel engines, gas turbines, electric
propulsionsystems, and alternative fuels such as LNG (liquefied natural gas).
 Example: Marine diesel engines (e.g., MAN B&W), pod propulsion systems.
 Applications: Cargo ships, passenger ferries, naval vessels.
7. Hydrodynamics and Fluid Mechanics:
 The study of water flow and its effects on ships and marine structures.
 Hydrodynamic principles are used to optimize hull shapes, reduce drag, and improve
 efficiency in marine vehicles.
 Example: Computational fluid dynamics (CFD) simulations, model testing in towing
tanks.
 Applications: Hull design, propeller optimization, resistance reduction.
8. Marine Materials and Corrosion Protection:
 Selection of materials and coatings for marine environments to prevent corrosion and
deterioration.
 Marine materials must withstand exposure to saltwater, waves, and marine
organisms,requiring corrosion-resistant alloys and protective coatings.
 Example: Stainless steel, aluminum alloys, anti-corrosion paints.
 Applications: Ship hulls, offshore structures, marine equipment.
9. Navigation and Positioning Systems:
 Technologies for determining the location, heading, and movement of vessels at sea.
 Navigation systems include GPS (Global Positioning System), radar, AIS
(AutomaticIdentification System), and gyrocompasses.
 Example: Electronic chart displays (ECDIS), radar systems, GPS receivers.
 Applications: Safe navigation, collision avoidance, maritime traffic management.
These technologies play a vital role in the marine sector, enabling safe, efficient, and sustainable
operations for commercial shipping, naval activities, offshore exploration, and renewable
energyproduction.
 Part-B Engineering Materials

Short Answer questions

1. What are the classes of materials?
Ans: Materials are classified based on their chemical, mechanical, and physical properties. Ceramics,
Metals, Polymers and Composites are the four main classifications of materials
2. Why are we studying engineering materials?
Ans: Engineering materials physical, Mechanical, Thermal and electrical characteristics are studied
to select and use the materials for various engineering applications.
3. How do engineers select materials?
Ans: Engineers select materials based on their performance, cost, availability, and past track record in
similar applications. Because the production of engineering materials involves consuming natural
resources and energy, environmental concerns are also factors in the selection process.
4. Differentiate ferrous and non-ferrous materials.
Ans: Ferrous materials are iron based materials like steels, stainlesss steels, tool steels etc. Non
ferrous materials are non iron based materials like copper, aluminium, nickel, lead and tin.
5. Draw the stress-strain curve of structural steel.

6. What is the difference between elastic and plastic regions?

Ans: In elastic region strain is temporary , whereas in plastic region strain is permanent.
Ceramics
7. Give examples of ceramics.
Ans: Alumina, Silicon carbide, Magnesia
8. What are the important characteristics of ceramics?
Ans: An essential characteristic of ceramics is that they can withstand extreme temperatures and
insulate other mechanical components
Composites
9. What is composite?
Ans: Composites are mixtures of several materials, and their formulation can be customized and tailored
for specific applications. Some composite materials comprise a polymer matrix (usually epoxy or
polyester) reinforced by many small-diameter fibers of glass, carbon, or Kevlar.
10. What are the constituents of composites?
Ans: Composite materials generally comprise two components: the matrix and the reinforcement. The
matrix is a relatively ductile material that holds and binds together the strong reinforcing particles or
embedded fibers.
11. How do composites exhibit superior performance?
Ans: Composite materials have higher strength and modulus to weight ratios than traditional
engineering materials..
Smart materials
12. What is smart material?
Ans: Smart materials are those that exhibit coupling between multiple physical domains. Common
examples of these materials include those that can convert electrical signals into mechanical
deformation and can convert mechanical deformation into an electrical output.
13. Give the types of smart materials.
Ans:Piezoelectric materials., Shape memory materials., Chromoactive materials., Magnetorheological
materials., Photoactive materials.
14. List the examples of physical domains and associated state variables.

15. List any four applications of smart materials.

Ans: Smart structures are used in several shape and vibration control applications. Micro positioning,
satellite antenna,shape control structure shape correction and automatic flow control valves are some of
the practical examples .

Descriptive Questions:
1. What are engineering materials? Give their classification.
Engineering Materials
One should understand some of the fundamental characteristics of engineering materials for how they
respond when subjected to stress. The next step involves deciding what type of material should be used
in a particular design application. Various materials are available for engineering products; choosing the
correct ones is essential to the design process. Mechanical engineers select materials in the context of
the product’s purpose and the processes used during its manufacture. The main classes of materials
encountered in mechanical engineering are as follows.
 Metals and their alloys
 Ceramics
 Polymers
 Composite materials
Electronic materials comprise another class, including the semiconductors used widely in electronic,
computer, and telecommunication systems. Microprocessors and memory chips use metal, electrical
conductors, and ceramic materials as insulators.
Engineers select materials based on their performance, cost, availability, and past track record in similar
applications. Because the production of engineering materials involves consuming natural resources and
energy, environmental concerns are also factors in the selection process.
Metals and Their Alloys
Metals are relatively stiff and heavy materials. In other words, from a technical standpoint, they
generally have large values for their elastic modulus and density. The strength of metals can be
increased by mechanical and heat treatments and alloying (adding small amounts of other carefully
chosen elements to a base metal).
From a design standpoint, metals are a good choice for structures and machines carrying large forces.
On the negative side, metals are susceptible to corrosion, and, as a result, they can deteriorate and
weaken over time. Another attractive feature of metals is that many methods exist to make, shape, and
attach them. Metals are versatile because they can be manufactured by casting, extrusion, forging,
rolling, cutting, drilling, and grinding.

2. List the Engineering Materials on basis of natural and manmade existence.

Ans: Soil, Rubber , Petroleum (Fuel), Inorganic materials (stone), Composites (clay, porcelain) Wood (rattan,
bamboo, bark ), Metal (copper, bronze, iron, gold, silver), Natural fibers (wool, silk, cotton, flax, hemp are some of the
natural materials used in day to day life.
Types of manufactured materials which are used in Regular practice are include alloys,
plastics, composite materials, industrial chemicals, soaps and detergents.
Engineering materials are broadly divided into Metals, Ceramics, Composite Materials and Polymers.
Natural availability of Metals in pure form does not possess good characteristics in all respects. Hence
to obtain various futures according the requirement and application Metals aree combined with other
elements and alloys are obtained. Like adding carbon, Nickel, Chromium etc. to ferrous materials
provides good ductility, strength, hardness and toughness. Adding copper to gold provides good
strength. Brass and Bronze are obtained by alloying zinc and nickel.
Composites are also naturally available like wood, bone, teeth etc. Composites are also prepared by
using natural fibres as reinforcement like jute, hemp, sisal etc. Carbon , glass and armid fibres also
used ass reinforcement to obtain light weight and high specific strength materials for aerospace and
other applications where weight reduction is the primary requirement.
Naturally available ceramics are quartz, sand and clay. To provide thermal insulation, electrical
resistance, free from humidity and corrosion effects various manmade ceramics are used in
engineering applications. They are like Alumina, Silicon carbide, Magnesia etc.
Natural polymers occur in nature and can be extracted. They are often water-based. Examples of
naturally occurring polymers are silk, wool, DNA, cellulose and proteins.
Manmade polymers are synthetic polymers include nylon, polyethylene, polyester, Teflon and
Epoxy. Nylon and polyester are commonly used in cloth making. Teflon is used in engineering
application to withstand high temperature. Epoxy is used as matrix or composite materials
preparation.

3. Write about ferrous and non-ferrous metals.

Ferrous and Non-Ferrous Metals:

Metals are by far the most used materials in manufacturing. Metals can be classified further into
those that are ferrous and those that are non-ferrous as shown in Figure.
Ferrous Materials:
As their name suggests, ferrous materials are iron-based metals.
These can be further categorized as irons & steels. This will form the basis for this brief of ferrous metals.
Wrought Iron
 It has been produced since the late eighteenth century.
 It contains very low carbon content less than < 0.1% carbon
 It contains 1–3% finely divided slag, evenly distributed throughout the metal
 It is highly malleable & ductile, i.e., easily shaped & worked by hammering, bending & rolling.
 Good in Corrosion Resistance.
 However, with the beginning of steel production, its use has turn down significantly.
 Example: It is generally used for products subjected to corrosive conditions.
 Applications: Decorative Items (as easily shaped), Architectural Elements, Historical
Restoration, Artwork Sculptures (easy workability).
Cast Iron:
 Cast Iron refers to a family of ferrous alloys
 It contains of iron & 2–4.5% carbon
 3.5% silicon is usually added to ease the casting by improving fluidity.
 Few Types of Cast Iron (2 – 4.5 C%):
 Gray Cast Iron: Engine blocks, cylinder heads, brake discs.
 White Cast Iron: Mill liners, crusher jaws, grinding balls.
 Malleable Cast Iron: Pipe fittings, hand tools, agricultural equipment.
 Ductile Cast Iron: Crankshafts, camshafts, gears.
 Graphite Cast Iron: Cylinder liners, turbocharger housings, brake rotors.
 Applications: Where High strength and ductility are needed.
 Automotive Industry, (Engine Components),
 Construction (Pipes, Manhole Covers, Machines),
 Machinery (Flywheels, Housings),
 Mining (Crushing Equipment),
 Manufacturing (Grinding Tools & Equipment),
 Agriculture (Plow Tips, Implement Parts)
Carbon Steels:

Carbon steels can be classified as

1. Low Carbon Steels,
2. Medium Carbon Steels,
3. High-Carbon Steels.
1. Low-Carbon steels:
 It contains less than < 0.2 % carbon and are generally referred to as Mild Steel.
 It is generally used as sheets and plates.
 It has soft, malleable, good weldability and machinability.
 Example: Mild Steel (e.g., ASTM A36), AISI 1018., Stainless Steel
 Applications: Widely used in construction (structural beams, plates), automotive (body
panels, chassis), and general engineering applications.
2. Medium-Carbon steels:
 It contain between 0.3 - 0.8 % carbon.
 Medium carbon steel offers higher strength, high hardness and wear resistance compared
to low carbon steel. It can be heat-treated to improve its mechanical properties.
 These steels generally have good fatigue resistance, toughness, strength, and hardness
 Used for components for automotive applications such as gears and crankshafts.
 Example: Medium Carbon Steel (e.g., AISI 1045), EN 8.
 Applications: Used in machinery components (shafts, gears), hand tools (wrenches,
hammers), and structural components where higher strength is required.
3. High-Carbon steels:
 It have greater than > 0.8 % carbon.
 High carbon steel is exceptionally strong & hard, but also less ductile & more brittle
compared to low and medium carbon steels. It can be hardened through heat treatment.
 Typical applications for these steels are for cutting tools, springs, and cables.
 Example: High Carbon Steel (e.g., AISI 1095), EN 9.
 Applications: Cutting tools (knives, blades), springs, wire ropes, where hardness and
wear resistance are critical.
Stainless Steel: (One of the low Carbon steel)
 Stainless steel is a versatile & corrosion-resistant alloy primarily composed of iron,
chromium & varying amounts of other elements such as nickel, manganese &
molybdenum.
 It is a special high alloy steel with greater than > 12 % chromium.
 The addition of chromium provides stainless steel with its corrosion-resistant properties.
 This which is the main reason for its use. They also exhibit high strength and ductility.
  Example: AISI 304 (18-8 stainless steel), AISI 316 (marine grade stainless steel).
 Applications: Food Processing Equipment, Kitchen Appliances, Chemical Processing
Plants, Architectural Structures, And Medical Devices, Refrigerators and Washing Machines,
Surgical Instruments, Industrial Blades, And Valve Components.

Tool Steels
 It is another special category of alloy steels used for cutting tools and dies.
 They contain up to 18 % tungsten, which improves the hardness.
 High-speed steel (HSS) is one such alloy steel that contains tungsten and the alloying element
vanadium (for increased strength).

Non-Ferrous Metals
Non-ferrous metals are mostly used as alloys. These can be categorized as
1. Light Alloys,
2. Heavy Alloys,
3. Refractory Metals,
4. Precious Metals.
1. Light alloys:
 Generally, light alloys are used where it is need of ,
 High strength-to-weight ratio.
 Weight reduction is Crucial.
 Light alloys are metallic alloys with low densities.
 It is typically composed of lightweight metals such as aluminum, magnesium, and titanium,
along with other elements like lithium and beryllium.
Some common types of light alloys:
i. Aluminum Alloys:
ii. Magnesium Alloys
iii. Titanium Alloys
i. Aluminum Alloys:
 Aluminum alloys are alloys,
 Primarily composed of aluminum as the base metal,
 Along with other elements such as copper, zinc, magnesium, and silicon.
 Aluminum alloys are
 Lightweight,
 Corrosion-Resistant,
  Exhibit Good Mechanical Properties.
 Good Electrical Conductivity.
 They offer high strength, excellent formability, and are easy to machine and weld.
 Example: 6061-T6 (a common general-purpose aluminum alloy), 7075-T6 (high-strength
aluminum alloy).
 Application: Aluminum alloys find extensive use in aerospace (aircraft structures,
fuselage panels), automotive (engine components, body panels), construction (structural
frames, window frames), marine (boat hulls, components), and consumer goods (bicycle
frames, sports equipment).
ii. Magnesium Alloys:
 Magnesium alloys are alloys,
 Predominantly composed of Magnesium as the base metal,
 Along with elements such as aluminum, zinc, and manganese.
 Magnesium alloys are
 Lightest Structural Metallic Materials,
 Excellent in Strength-To-Weight Ratios.
 They are Highly Machinable,
 Have Good Damping Capacity,
 Resistant to Electromagnetic Interference.
 Example: AZ91 (general-purpose magnesium alloy), WE43 (high-strength magnesium
alloy).
 Application: Magnesium alloys are used in aerospace (aircraft components, helicopter
transmissions), automotive (steering wheels, engine blocks), electronics (laptop casings,
smartphone frames), and medical devices (implants, surgical instruments).
iii. Titanium Alloys:
 Titanium alloys are alloys,
 Primarily of titanium as the base metal,
 Along with other elements such as aluminum, vanadium, and iron.
 Titanium alloys offer,
 Combination of high strength, light weight (low density), and
excellent corrosion resistance, even in harsh environments.
 They have a high melting point
 Retain their mechanical properties at elevated temperatures.
 They are also far more expensive and difficult to machine than other metals.
 Example: Ti-6Al-4V (common titanium alloy), Ti-6Al-2Sn-4Zr-2Mo (high-strength
titanium alloy).
  Application: Used in aerospace (aircraft components, jet engine parts), medical
(implants, prosthetics), marine (ship components, offshore structures), sports equipment
(bicycle frames, golf clubs), and military applications. aircraft, material-handling
equipment, and portable power tools.
2. Heavy Alloys:
 Heavy alloys are slightly heavier than steel.
 Most of the heavy alloys are Copper alloys.
Copper Alloys:
 Copper alloys are
 Primarily of copper (usually more than 50% by weight)
 Along with other elements such as zinc, tin, aluminum, nickel, and silicon.
 These alloys exhibit a wide range of mechanical, thermal, and electrical properties
depending on their composition.
 Copper Alloys offer,
 High Electrical Conductivity,
 Corrosion Resistance,
 Ease of Fabrication.
 It is categorized as
a. Brass (70% copper, 30% zinc)
b. Bronze. (80% copper, 20% Tin)
 Brasses (which are yellowish alloys of copper and zinc)
 Bronzes (which are brownish alloys of copper and tin).
 These materials have particularly reasonable strengths & ductility,
 But they are resistant to corrosion and can be easily joined by soldering.
 Example: Brass, Bronze
 Applications: Gears, bearings, and tubing in condensers and heat exchangers. Automotive
radiators, radiator cores, and plumbing components.
3. Refractory metals:
 The most common metals in this group are molybdenum, niobium, tantalum, and tungsten.
 Refractory metals are a group of metals known for their,
 Exceptional resistance to heat, wear, and corrosion at high temperatures.
 These metals have melting points above > 2000°C
 Possess excellent mechanical properties even at elevated temperatures.
 Excellent thermal conductivity, allowing them to withstand extreme heat without
oxidizing.
  They are widely used in applications that require extreme heat resistance and
durability.
 Example:
 Tungsten(W) – with Melting Point 3422°C
 Tantalum (Ta) – with Melting Point 2996°C
 Molybdenum(Mo) – with Melting Point 2623°C
 Niobium (Nb) – with Melting Point 2468°C
 Rhenium(Re) – with Melting Point 3186°C
 Applications: Turbine blades, rocket nozzles, heat shields, missile components, High-
temperature furnace components, metalworking tools, Heat exchangers, reaction vessels,
catalysts, furnace linings, radiation shielding.
4. Precious Metals:
 Gold, silver, and platinum are the most important precious metals.
 Despite their high cost, all three are used for industrial applications.
 Example:
 Gold has good corrosion resistance & ductility. Used for electrical contacts & terminals.
 Silver is used for electrical contacts. & It has the highest electrical & thermal
conductivity among metals.
 Platinum is ductile and is resistant to corrosion at high temperatures.
 Applications: Electrical contacts, spark-plug electrodes, and catalysts in exhaust systems.

4. Draw and Explain stress strain diagram for ductile materials (Steel)
The stress–strain diagram is broken down into two regions:
 Low-strain elastic region: After the force applied and removed - No permanent deformation, set
back to original state (elastic region)
 High-strain plastic region: Force is large, upon removal, the material has permanently
elongated (Plastic region).

Stress-strain curve for structural steel

  For strains below the proportional limit (point A). From the diagram that stress and strain are
proportional to one another and that they therefore satisfy the relationship σ = E ε.
 The quantity E is called the elastic modulus, or Young’s modulus, and it has the dimensions of
force per unit area. In the SI, the units MPa are typically used for the elastic modulus. The elastic
modulus is a physical material property, and it is simply the slope of the stress–strain curve for
low strains.

5. What are the characteristics of ceramic materials? Give their usage

Ceramics
 Thinking of ceramics, images of coffee mugs, dinner plates, & artwork probably come to mind.
 Ceramics encompassing,
 Withstanding extreme High temperatures
 Corrosion resistance,
 Electrical insulation & insulate other mechanical components from heat.
 Wear resistance.
 Hard & Brittle
 Engineering ceramics are used in the automotive, aerospace, electronics, telecommunications,
computer, and medical industries for applications encompassing Ceramics properties.
 Process: Heating naturally occurring minerals and chemically treated powders in a furnace to form a
rigid mechanical component.
 They are often processed through techniques such as shaping, firing, and sintering to achieve
desired shapes and properties.
 Crystalline materials comprising metals and nonmetals.
 Ceramics derive their unique properties from their atomic and microstructural arrangement, which
typically involves strong chemical bonds between atoms or ions. Unlike metals, ceramics do not
have free electrons for electrical conductivity, resulting in electrical insulating properties.
 Ceramics are brittle and tend to break suddenly when overloaded, they are not appropriate for
supporting large tensile forces.
 Mechanical Ceramic components become significantly weakened by small defects, cracks, holes,
and bolted connections.
 Ceramics can be classified based on their composition, structure, and properties, with common types
including oxides, nitrides, carbides, and silicates.
Types of Ceramics:
Ceramics can be categorized into several types based on their composition and properties:
i. Oxide Ceramics
ii. Nitride Ceramics
iii. Carbide Ceramics
iv. Silicate Ceramics
 i. Oxide Ceramics:
 These ceramics are composed of metallic elements bonded with oxygen and exhibit high
thermal stability, corrosion resistance, and electrical insulation properties.
 Known for its high hardness, wear resistance, and chemical inertness.
 Example: Alumina (Al2O3), Zirconia (ZrO2), and Silica (SiO2).
 Applications: cutting tools, abrasives, electrical insulators, and biomedical implants.
ii. Nitride Ceramics:
 Nitride ceramics are composed of metallic elements bonded with nitrogen and possess
high hardness, thermal conductivity, and chemical resistance.
 Known for its high strength, toughness, and thermal shock resistance.
 Example: Silicon Nitride (Si3N4) and boron nitride (BN).
 Applications: as bearings, turbine blades, and automotive engine components.
iii. Carbide Ceramics:
 Carbide ceramics are composed of metallic elements bonded with carbon and exhibit high
hardness, wear resistance, and thermal conductivity.
 Example: Silicon Carbide (SiC) and Tungsten Carbide (WC), Titanium Carbide (TiC),
iv. Silicate Ceramics:
 Silicate ceramics are composed of silicon and oxygen atoms bonded with metallic
elements such as aluminum, magnesium, or calcium. They are commonly used in pottery,
building materials, and electronic substrates.
 Known for its smooth surface, translucency, and resistance to staining.
 Example: clay, porcelain, and glass.
 Applications: dinnerware, sanitary ware, and electrical insulators.
Some Common Applications:
 Electronics: Insulators, substrates, capacitors, resistors, semiconductor components.
 Automotive: Engine components, exhaust systems, brake pads, catalytic converters.
 Aerospace: Turbine blades, heat shields, thermal barrier coatings, spacecraft
components. Thermal barrier coatings to protect turbine blades from the high
temperatures developed in jet engines.
 The space shuttle used tens of thousands of lightweight ceramic tiles to insulate the
spacecraft’s structural frame from temperatures that reached 1260°C during
reentry.
 Medical: Dental implants, bone substitutes, surgical instruments, prosthetic limbs.
 Construction: Tiles, bricks, refractory materials, cement, glass fibers.
 Energy: Insulators, thermal insulation, fuel cells, solar panels, nuclear reactor
components.
Glass Ceramics : Glass ceramics are a special class of materials that combine the properties of both glass and
ceramics.
Applications : Cookware, glass-ceramic cooktops, dental restorations.
6. What is a composite material? List the fibres, matrices, and applications.

 Composites are materials composed of two or more distinct constituents with different
physical or chemical properties, combined in a macroscopic level to create a new material
with enhanced properties not achievable by any of the individual components alone.
 Composites are mixtures of several materials, and their formulation can be customized
and tailored for specific applications.
 Composites are commonly classified based on the type of reinforcement and matrix materials
used.
 Composite materials generally comprise two components:
 The Matrix
 The Reinforcement.
 The Reinforcement Phase (e.g., fibers, particles, laminar layers,) provides
specific mechanical, thermal, or electrical properties.
 While the Matrix Phase (e.g., polymers, metals, ceramics, hybrid
materials) serves to bond and support the reinforcement.
• The matrix is a relatively ductile material that holds and binds
together the strong reinforcing particles / fibers.

 By selecting appropriate reinforcement and matrix materials and optimizing their

arrangement and processing, composites can be tailored to meet specific performance
requirements such as strength, stiffness, toughness, weight savings, corrosion resistance,
and thermal stability.
 Composites are not well suited for high temperatures because, like plastics and
elastomers, the polymer matrix softens as the temperature increases.
 The main idea behind fiber-reinforced composites is that the strong fibers carry most of
the applied force.
 They can be stiff, strong, and lightweight.
 The widespread usage of fiber-reinforced composite materials beganin the aerospace
industry, where weight is at a premium. A substantial amount of an aircraft’s weight can
be reduced by incorporating composite materials into the airframe, horizontal and vertical
 stabilizers, flaps, and wing skins.
 Function of Matrix:
 Provides the bulk form of the part
 Holds the embedded phase together.
 Protects the fibers from environment.
 Distributes the loads evenly between fibers
 Functions of Reinforcement:
 Function is to reinforce the primary phase
 Properties of Matrix:
 Reduced moisture absorption
 Low shrinkage
 Good flow characteristics
 Must be elastic to transfer loads to fibers
 Reasonable strength
 Advantages:
 Low Density  High corrosion resistance
 High specific Strength  High resistance to impact damage
 High specific Stiffness  Low coefficient of thermal expansion
 High Fatigue properties  Low thermal conductivity
 Long fatigue life  Better wear resistance
 High creep resistance  Better temperature dependent.
 Examples:
 Concrete enforced with steel rods.
  These automobile tires include steel reinforcing belts in an elastomer
matrix
 Power transmission belts that usess fiber or wire cords to carry the belt’s
tension.
 Glass fibers dispersed in a polymer matrix
 Carbon fibers embedded in a polymer matrix
 Metallic fibers or particles embedded metal matrices

 Applications:
 Approximately 30% of the external surface area of the Boeing 767 commercial
airliner is formed from composite materials.
 As the technology of composites has matured and costs have decreased,
these materials have been adopted in automobiles, spacecraft, boats,
architectural structures, bicycles, skis, tennis rackets, and other consumer
products.
 Aerospace: Space shuttle tiles, thermal barriers, high temperature glass
windows,
 Military: Ceramic armour, structural components for ground, air and
naval vehicles,missiles and sensors.
 Automotive: Catalytic converters, ceramic filters, airbag sensors, spark
plugs, pressure sensors, vibration sensors, oxygen sensors, safety glass
windshields, piston rings.
 Computers: Insulators, resistors, superconductors, capacitors, ferroelectric
components,microelectronic packaging.
 Consumer durable: Glassware, windows, pottery, dinnerware, ceramic
tiles, homeelectronics, microwave transducers.

7. Define smart material. Explain the types of smart materials and their functions.
 Smart materials are those that exhibit coupling between multiple physical domains.
Common examples of these materials include those that can convert electrical signals
into mechanical deformation and can convert mechanical deformation into an electrical
output.
 Smart materials, also known as responsive materials or intelligent materials, are a class of
materials that have the ability to change their properties in response to external stimuli,
 such as temperature, stress, light, magnetic fields, or electric fields.
 Smart materials are materials that possess inherent properties or functionalities to sense,
respond, adapt, or self-regulate in response to external stimuli (changing environment).
These materials can exhibit reversible or irreversible changes in their physical, chemical,
mechanical, or electrical properties under specific conditions, enabling them to perform
predefined functions or tasks without the need for external control mechanisms.
 Smart materials derive their unique properties from their molecular or microstructural
design, which enables them to undergo reversible or irreversible changes in response to
external stimuli.
 These changes can include,
 Alterations in shape,
 Size, color, conductivity,
 Stiffness, viscosity, or magnetic permeability, among others.
Smart materials typically exploit phenomena such as,
 Shape memory effect,
 Piezoelectricity,
 Magnetostriction, electrostriction,
 Thermo responsive behavior, or photo mechanical effects to
achieve theirdesired functionality.
Smart materials, also known as responsive materials or intelligent materials, are a class of
materials that have the ability to change their properties in response to external stimuli, such as
temperature, stress, light,
magnetic fields, or electric fields. These materials exhibit dynamic behavior, allowing them to
sense,respond, adapt, and self-regulate their characteristics to the changing environment.

Types of Smart Materials:

i. Shape Memory Alloys (SMAs)

ii. Piezoelectric Materials
iii. Electrorheological (ER) and Magnetorheological (MR) Fluids
iv. Thermoresponsive Polymers
v. Photochromic and Thermochromic Materials

i. Shape Memory Alloys (SMAs):

 SMAs are metallic alloys that can "remember" their original shape and
 return to it after deformation when subjected to changes in temperature or
stress.
 Examples: Nickel-titanium (Nitinol) alloys used in medical devices, aerospace
actuators.
ii. Piezoelectric Materials:
 Piezoelectric materials generate an electric charge in response to mechanical
stress or deformation, and vice versa.
 Examples: Lead zirconate titanate (PZT) ceramics used in sensors, actuators,
energy harvesters, and ultrasonic devices.
iii. Electrorheological (ER) and Magnetorheological (MR) Fluids:
 ER and MR fluids change their viscosity in response to an electric field (ER
fluids) or magnetic field (MR fluids).
 Example: They are used in Electrorheological fluid-based dampers, shock
absorbers, clutches, and Magnetorheological (MR) Fluids based actuators,
adaptive structures to control vibration, noise, and motion.
iv. Thermoresponsive Polymers:
 Thermoresponsive polymers undergo reversible changes in their physical state,
such as swelling or shrinking, in response to changes in temperature.
 Example: Poly(N-isopropylacrylamide) (PNIPAAm) hydrogels used in drug
delivery, tissue engineering
v. Photochromic and Thermochromic Materials:
 These materials change color in response to changes in light intensity
(photochromic) or temperature (thermochromic).
Example: Photochromic eyeglass lenses, thermochromic paints, and smart windows.

8. How multiple physical domains were combined? Explain with example properties.
Smart materials are those that convert energy between multiple physical domains. A domain is
any physical quantity that we can describe by a set of two state variables. A state variable pair
can be thought of as a means of defining size or location within a physical domain.
An example of a physical domain that we study at length is the mechanical domain,
whose state variables are the states of stress and strain within a material. Another example of a
physical domain is the electrical domain, whose state variables are the electric field and electric
displacement of a material. Other examples are the thermal, magnetic, and chemical domains Fig.
 Fig. Examples of physical domains and associated state variables
 Physical domains and associated state variables allows us to be more precise in coupling.
Coupling occurs when a change in the state variable in one physical domain causes a
change in the state variable of a separate physical domain. Coupling is generally
denoted by a term that is a combination of the names associated with the two physical
domains. For example, changing the temperature of a material, which is a state variable in
the thermal domain, can cause a change in the state of strain, which is a mechanical state
variable. This type of coupling is called thermo mechanical coupling because the
coupling occurs between the thermal and mechanical physical domains.
 A visual representation of the notion of physical domains and the coupling between them
is shown in Fig. Each rectangle represents a single physical domain, either mechanical,
electrical, or thermal. Listed in each rectangle are the state variables associated with the
domain.
 The bridge within the rectangle is the physical property that relates to the state variables.
 The elastic properties of a material relate to the states of stress and strain in the material,
and the dielectric properties relate to the electrical state variables.
 The coupling between the physical domains is represented by the arrows that connect the
rectangles.
 For example, the electrical output produced by a thermal stimulus is termed the
pyroelectric effect.
 Similarly, the variation in mechanical stress and strain due to a thermal stimulus is termed
thermal expansion.
 Applications:
 Smart structures are used in several shape and vibration control
applications. Micro positioning, satellite antenna,shape control structure shape
correction and automatic flow control valves are some of the practical
examples.

 Smart materials find diverse applications across various industries due to

their unique properties and functionalities. Some common applications
include:
 Aerospace: Adaptive wing structures, morphing aircraft components,
vibration controlSym.
 Automotive: Smart sensors, adaptive suspension systems, energy-harvesting
shockabsorbers, self-healing coatings.
 Biomedical: Drug delivery systems, tissue engineering scaffolds, smart
implants,biosensors, wearable health monitors.
 Consumer Electronics: Smart displays, adaptive lenses, touch-sensitive
screens, shape-changing gadgets.
 Civil Engineering: Structural health monitoring, adaptive building materials,
earthquake-resistant structures, smart bridges.
 Defense and Security: Bulletproof vests, self-repairing materials, sensors
for chemicaland biological detection.
 Subject: BCME
Unit V, Part-A

Manufacturing Processes: Principles of Casting

Short answer questions:
1. Define casting. List the casting defects.
Casting is the manufacturing process where liquid metal is poured into a mold
cavity,cooled, and solidified to obtain the product.
Casting defects are blow holes, Cold shuts, misruns, and slag inclusion
2. List three advantages and disadvantages of
casting.Advantages:
• The cost involved is low compared to other manufacturing processes.
• The casting process can manufacture heavy and bulky parts.
• Casting can be employed for mass production.
Disadvantages:
• Low dimensional accuracy
• Low Mechanical strength
• Poor surface quality and more defects
3. Define a pattern.
A pattern is a model or a replica of the object to be manufactured.
4. What are the materials used for pattern making?
Patterns are made using wood, metals, plastics, plaster, and wax.
5. Explain the need for a riser in casting.
During the solidification of casting shrinkage happens. To compensate liquid
shrinkage riser is provided.
Descriptive Questions:
6. Explain the steps involved in casting.
Steps involved in Casting:
1. Pattern Making
2. Mould Preparation
3. Melting of Metal
Page 1 of 25
 4. Pouring of Metal
5. Solidification
6. Removing the Casting
7. Finishing
8. Inspection

1. Pattern Making:
• Creating a pattern of the desired object typically made of wood, plastic, or metal, which
serves as a template for the casting process.
2. Mold Preparation:
• Making a mold around the pattern, usually using materials like sand, clay, or plaster. This
mold will form the negative space into which the molten material will be poured.

3. Melting:
• Melting the material to be cast, such as metal or plastic, in a furnace or other heating
apparatus to bring it to a molten state.
4. Pouring:
• Pouring the molten material into the mold cavity created by the pattern. This requires careful
control of temperature, pouring speed, and direction to ensure quality.
5. Solidification:
• Allowing the molten material to cool and solidify inside the mold. This may involve cooling
the mold itself or letting the material cool naturally.
6. Mold Removal:
• Removing the mold from the solidified casting, which may involve breaking or separating the
mold material from the casting.
7. Finishing: Page 2 of 25
 • Trimming off excess material, smoothing rough edges, and performing any additional
machining or surface treatments to achieve the desired final shape and surface finish.
8. Inspection:
• Inspecting the casting for defects, dimensional accuracy, and other quality criteria to ensure it
meets specifications and next stage of production and shipping.
7. Explain the casting process and its advantages with a neat sketch
Principles of Casting:
• Metal casting is one of the most versatile forms of production processes. There is no limit to the
size and shape of the articles that casting can produce. The production cost is considerably low.
• Although all metals can be cast, iron is mainly used because of its fluidity, small shrinkage, and
ease with which its properties are controlled.
• The casting process involves pouring molten metal into a cavity or mold of the desired shape &
size and allowing it to solidify.
When it is removed from the mold, the casting is of the same shape but slightly smaller due to the
contraction of metals.

Steps involved in Casting:

1. Pattern Making
2. Mould Preparation
3. Melting of Metal
4. Pouring of Metal
5. Solidification
6. Removing the Casting
7. Finishing
8. Inspection
Application:
▪ Automotive Industry: Manufacture engine blocks, transmission cases, pumps, valves
▪ Jewelry Making: Intricate designs in gold, silver, and other precious metals.
▪ Aerospace Industry: Turbine blades for jet engines.
▪ Art and Sculpture: Artists sculptures, art pieces in materials such as bronze and plaster.
▪ Medical Devices: hip replacements, dental crowns, and orthopedic implants
▪ Kitchen utensils: Pots, pans, and other aluminum kitchen utensils.

Page 3 of 25
 Fig. Steps involved in the casting process

Forming
Short answer questions:
8. What is forming?
Forming encompasses a family of techniques whereby a raw material is shaped by
stretching, bending, or compression. Large forces are applied to plastically deform a material
into its new permanent shape.
9. Differentiate blanking and piercing.
If the sheared-off part is the one required, the process is referred to as blanking, and if
the remaining part in the sheet is the one required, the process is referred to as piercing
10. List out standard sheet metal processes. 2M
Shearing, Deep drawing, Bending, Spinning

Descriptive Question
11. With a neat schematic, explain how forming is done.
Different type of forming process are Rolling, Extrusion , Forging and sheet metal Operations.
▪ Some common types of forming processes are:
1. Forging
2. Rolling
3. Extrusion
4. Drawing
5. Molding
6. Bending
Page 4 of 25
7. Shearing,
 8. Blanking & Piercing
9. Machining
1. Forging:
▪ Forging is a manufacturing process in which a metal workpiece is shaped by applying
compressive force using hammering, pressing, or rolling.
▪ Forging improves the mechanical properties of metals by aligning the grain structure and
eliminating porosity, resulting in stronger and more durable parts.
▪ Example: Common forged products include crankshafts, connecting rods, gears, and tools.
▪ Applications: Automotive, aerospace, construction, military, industrial machinery.

2. Rolling:
▪ Rolling involves passing a metal workpiece through a pair of rolls to reduce its thickness or change
its cross-sectional profile, to make the thickness uniform, and/or to impart a desired mechanical
property.
▪ The rolls exert compressive forces on the workpiece, causing it to deform plastically.
▪ Example: Rolling is used to produce sheets, plates, and structural shapes like beams and rails.
▪ Applications: Steel and aluminum industries heavily rely on rolling processes for the production of
various products used in construction, transportation, and manufacturing, aircraft wings and
fuselages, beverage containers and the body panels of automobiles.

Page 5 of 25
3. Extrusion:
▪ Extrusion is a manufacturing process in which a material is forced through a die to create a
specific cross-sectional profile (Round, Rectangular)
▪ In extrusion, a mechanical or hydraulic press is used to force heated metal through a tool
(Called die) that has a tapered hole ending in the shape of the finished part’s.
▪ The material is pushed through the die under high pressure, taking the shape of the die's opening.
▪ The die is used to shape the raw material, and it is made from a metal that is much harder than
what is being formed.
▪ Extrusion is used for producing continuous lengths of uniform cross-sections and is particularly
well-suited for forming metals, plastics, and food products.
▪ Example: Aluminum window frames, PVC pipes, plastic film, metal rods, tubes.
▪ Applications: Construction, automotive parts, packaging, food processing.

4. Drawing:
▪ Drawing is a forming process in which a material is pulled through a die to reduce its cross-
sectional area and increase its length.
▪ Drawing is a process in which a blank is pressed into a shaped die to form an open-ended -
cylindrical shape, such as a can.
▪ The process is known as deep drawing if the cylinder depth is greater than or equal to the
radius of the base.
▪ Example: Wire drawing, tube drawing, and other elongated shapes with consistent dimensions.
▪ Applications: Automotive, electronics, construction, medical devices.

Page 6 of 25
5. Molding:
▪ Molding is a manufacturing process in which a material is shaped by applying pressure or heat.
▪ Molding processes are versatile and can be used with a wide range of materials, producing
complex shapes with high efficiency.
▪ Example: Injection molding (plastics), compression molding (rubber), blow molding (bottles).
▪ Applications: Consumer goods, packaging, automotive, medical devices.

6. Bending:
▪ Bending is a forming process in which a material is bent to a specific angle or shape.
▪ Bending is commonly used for creating curved or angular shapes in sheet metal and other
materials.
▪ Example: Metal brackets, tubing, wire forms.
▪ Applications: Construction, automotive, furniture, HVAC.

7. Shearing:
▪ Shearing is a cutting process that involves the use of two blades or sharp edges to trim or
separate a material along a straight line.
▪ In shearing, one blade applies downward force while the other acts as a support, causing the
material to yield and fracture along the line of contact between the blades. This process is
Page
typically used for cutting sheet metal, 7 of 25
plates, or other thin materials.
 ▪ Example: Shearing is commonly used in metalworking to cut large metal sheets into smaller
pieces or to trim edges for precision.
▪ Applications: Shearing is widely utilized in industries such as metal fabrication, construction,
shipbuilding, appliance manufacturing, and agricultural equipment production.

8. Blanking & Piercing:

▪ Both Blanking & Piercing involve cutting operations, the primary difference lies in their
outcomes.
▪ Blanking: Results in the production of a flat shape or blank,
▪ Piercing: Creates holes or openings in the material.
▪ Blanking is typically used to produce discrete parts with defined outer shapes, while
Piercing is used to create holes or features within those parts or in standalone components.

▪ Blanking:
▪ Specialized tool called a Blanking Die is used to punch out the desired shape
from the sheet metal. The punched-out piece, known as the blank, is the
intended final sproduct, while the remaining material is considered scrap.
▪ Blanking is a manufacturing process that involves cutting a flat piece of sheet
metal to create a flat shape or blank, typically with straight edges.
▪ Example: Production of washers from a sheet of metal. The blanking die
punches out circular blanks from the sheet, leaving behind the scrap material.
These blanks are then further processed or used as-is in various applications.
▪ Applications: Washers, Brackets, And Connectors.
Page 8 of 25
 ▪ Piercing:
▪ Piercing is a manufacturing process that involves creating holes or openings in
sheet metal or other materials using a specialized tool, such as a punch &die set.
▪ In piercing, the punch applies downward force to penetrate the material, while
the die supports the material and helps define the shape of the hole. The resulting
hole may be the final product or used as a precursor for subsequent operations.
▪ Example: Metal components such as electrical enclosures, automotive chassis,
machinery parts where holes are needed for fasteners, wiring, or ventilation.
▪ Applications: Automotive, aerospace, construction, and electronics. It is essential
for creating holes of precise dimensions and shapes in sheet metal.
9. Machining:
▪ Machining is a manufacturing process in which material is removed from a workpiece to create a
desired shape using cutting tools.
▪ Machining allows for precise shaping of materials with tight tolerances, making it suitable for
custom or low-volume production runs.
▪ Example: CNC milling, turning, drilling, grinding.
▪ Applications: Aerospace, automotive, medical devices, tooling.

Joining Process: Short answer questions:

12. Define welding.
Welding is a metal joining process by the application of heat and force or only by the
application of heat to obtain the joint.
13. What is edge preparation in welding?
It is the preparation of the edges of metal pieces to be joined into some forms
dependingon the thickness of the metal and the types of welded joints.

14. What is weld penetration?

The depth up to which the weld metal combines with the parent metal is called metal
penetration. It is measured from the top surface of the joint.

Page 9 of 25
Descriptive questions:
15. What is joining? Explain the essential terms of welding with a neat sketch
Metal joining processes are manufacturing processes in which metal pieces are joined by
applying heat by some means.
Welding :
Welding is a metal joining process in which metals are joined by applying heat with or without pressure.
This can be realised by:
• Fusion welding – where the metal is melted to make the joint with no pressure involved.
• Resistance welding – where both heat and pressure are applied.
• Pressure welding – where pressure only is applied, e.g. to a rotating part where the heat
is developed through friction, as in friction welding.
▪ During welding, the edges of the metal pieces are heated over a higher range of temperatures, i.e.,
these are either melted or brought to a plastic condition and then allowed to cool.
▪ Welding processes may be classified into many types based on the Heat application method.
o In ARC welding, Heat is applied by producing an electric arc between two conductors,
o In GAS welding, Heat is applied by the combustion of a fuel gas with oxygen.
Basic Welding Terms
One should be familiar with the several technical terms used in welding technology.

▪ Parent Metal: Metal to be joined or surfaced by welding, braze welding or brazing.

▪ Filler Metal: Metal added during welding, braze welding, brazing or surfacing.
▪ Weld Metal: All metal melted during the making of a weld and retained in the weld.
▪ Heat Affected Zone (HAZ): The part of the parent metal metallurgically affected by the weld or
thermal cutting heat, but not melted.
▪ Fusion Line: Boundary between the weld metal and the HAZ in a fusion weld. This is a non-
standard term for weld junction.
▪ Weld Zone: Zone containing the weld metal and the HAZ.
Page 10 of
▪ Weld Face: The surface of a fusion weld
25 exposed on the side from which the weld has been made.
 ▪ Weld Root: Zone on the side of the first run furthest from the welder.
▪ Weld Toe: Boundary between a weld face and the parent metal or between runs.
▪ Excess Weld Metal: Weld metal lying outside the plane joining the toes. Other non-standard terms
for this feature: reinforcement, overfill.
▪ Root Gap: The distance between the edges of the base metals at the root of the weld joint. Root gap
is critical for controlling the penetration and fusion of the weld
▪ Root Face: The surface of the base metal adjacent to the root of the weld joint.
▪ Weld Bead: A continuous deposit of weld metal formed along the length of the weld joint.
▪ Backing: It is the metal support given below the root portion to control the penetration.
▪ Tack Welds: Two small welds made at the end of the joint for temporarily holding the metal pieces.
▪ Edge Preparation: It is the preparation of the edges of metal pieces to be joined into some forms
depending on the thickness of the metal and the types of welded joints.

16. Describe the process of arc welding.

Arc Welding
▪ Arc welding joins two metal pieces by melting their edges with an electric arc.
▪ An arc is an electric discharge through the ionized gas column between two conductors of
electricity, namely the cathode and the anode.
▪ When two conductors are touched and separated by a small distance, electrons are liberated from the
cathode and move toward the anode.
▪ Also, the positively charged ions move from the anode towards the cathode. The
impact of these electrons and positive ions at high velocity onto the conductors
liberates heat.
▪ An arc that generates heat can be obtained between an electrode and the workpiece,
between two electrodes and two metal pieces to be welded.
▪ The temperature of the arc is about average of 2500°C.
▪ Alternating current (AC) or Direct Current (DC) source can be used for arc welding.
▪ Power Source are two types are possible,
• In Direct Current Arc welding, power sources are usually D.C Generators,
• In Alternate Current Arc welding, the power sources are Transformers.
▪ In Direct Current arc (DC) welding are widely used, two types are possible,
▪ DCEN: Direct Current Electrode Negative
o Electrode connected to the negative terminal of the power source
and the workpiece to the positive terminal, it is also called as direct
Current Straight Polarity (DCSP) arc welding.
▪ DCEP: Direct Current Electrode Positive
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25
 o If the electrode is connected to the positive terminal of the power
source and the workpiece to the negative terminal, it is called Direct
Current Reverse Polarity (DCRP) welding.

Fig. Arc welding circuit

▪ Connections & Working:
• Electrode is held using an electrode holder,
• Workpieces are on a metal worktable.
▪ The electrode holder and the metal worktable are connected to different terminals of the
welding power source through long insulated cables. i.e., (DCEN, DCEP).
▪ Initially, the metal workpiece is touched with the electrode and then separated, leaving a
small gap between the electrode tip and the workpiece. This generates ARC & Heat – which
is used for Melting and Joining.
▪ The gap between the electrode and the workpiece, known as the Arc Length, is essential for
the arc to exist continuously.
▪ This must be maintained within a specified range for Good-Quality Welding. Once the arc
has been initiated, the electrode is moved along the length to complete the welding process.

17. What are the important types of metal joining processes?

• Metal joining process are Bolting, Riveting, Welding, Soldering and Brazing.
• Temporary joint: Bolting joint is.
• Semi-Temporary joint: Riveting Joining
• Permanent joints: Welding, Soldering and Brazing

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25
Bolting joint is temporary joint. Riveting Joining is semi permanent joint.

Welding, Soldering and Brazing are permanent joints.

Page 13 of
25
Explain about Brazing and Soldring:
Soldering:
▪ Soldering: Takes place at a temperature below 450°C
▪ Soldering is a process of joining two or more metal pieces by melting and flowing a filler metal
(solder) into the joint, which has a lower melting point than the workpieces (not melted) being
joined.
▪ Solder typically melts below 450°C
▪ Example: Soldering is extensively used in electronics for joining components on circuit boards. It
is also used in jewelry making, plumbing, and metalwork.
▪ Applications: Soldering is widely used in electronics manufacturing, including the assembly of
circuit boards, wiring, and electrical connections. It is also used in plumbing for joining copper
pipes and fittings, as well as in jewelry making and craftwork.
Brazing:
▪ Brazing: Takes place at a temperature above 450°C
▪ Brazing is a metal-joining process where a filler metal is heated above its melting point and
distributed between two or more close-fitting parts.
▪ Filler metal has a lower melting point than the base metals being joined but higher than 450°C.
▪ In brazing, the base metals do not melt; instead, the molten filler metal flows between them,
forming a strong bond when cooled.
▪ Example: Joining copper pipes in plumbing is a common example of brazing. Assembly of
various metal components in the automotive and aerospace industries.
▪ Applications: Brazing is used in various industries for joining dissimilar metals, Steel
Plumbing, Metal Working and assembling complex structures. It finds applications in
automotive, aerospace, electronics, and plumbing industries, among others.

Aspect Soldering Brazing

Temperature Range Typically below 450°C Typically above 450°C
Base Metal Works with both ferrous and non-
Usually non-ferrous metals and alloys
ferrous metals
Filler Metal Higher melting point than soldering
Lower melting point than base metals
filler
Joint Strength Generally weaker joints Typically stronger joints
Heat Affected Zone Smaller heat-affected zone Larger heat-affected zone
Application Electrical/electronic components, Automotive, plumbing, HVAC,
jewelry metalworking
Equipment Soldering iron, solder wire, flux Torch, filler metal, flux
Skills Required Requires more skill due to higher
Relatively easy to learn and perform
temperatures
Joint Appearance May appear bulkier due to higher
Usually neat and clean
heat input

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25
Short answer questions:
18. Why is cutting needed for a component?
To obtain the desired shape material is removed in the form of chips in machining
process.
19. Explain turning.
The turning operation is performed on a lathe where the workpiece rotates, and the tool
moves parallel to the center axis of the workpiece. The operation produces external
cylindrical surfaces for parts such as shafts and axles.
20. How milling is done?
Milling is the process of grinding, cutting, pressing, or crushing a material in a special
machine. Milling is the process of cutting away material by feeding a workpiece past a
rotating cutter with many teeth.

Page 15 of
25
 Descriptive Questions:
21. Why is machining required? Explain the basic mechanical machining operations.
Machining
▪ Machining is the processes whereby material is gradually removed from a workpiece as small
chips.
▪ The most common machining methods are drilling, shaping, milling, and turning.
▪ Machining operations can produce mechanical components with dimensions and shapes that are
far more precise than their cast or forged counterparts.
▪ One drawback of machining is that (by its very nature) the removed material with casting and
forging when cast or forged components requires additional operations to flatten surfaces, make
holes, and cut threads.
▪ Machining involves the shaping of a part through the removal of material.
▪ A tool constructed of a material harder than the part being formed is forced against the part,
causing the metal to be cut from it.
▪ Machining, also called cutting, metal cutting, or material removal, is the dominant manufacturing
process because it is the only process used for primary and secondary processing.
▪ The basic machining operations are,
i. Turning,
ii. Drilling,
iii. Milling,
iv. Shaping.
i.Turning:
▪ The turning operation is performed on a lathe
▪ The workpiece is clamped onto a lathe and rotated while a single-point cutting tool is
fed into it to remove material, producing cylindrical surfaces, such as shafts, rods, and
bushings.
❖ Tool: Single-Point Cutting Tool
▪ In Turning, the workpiece rotates, and the tool moves parallel to the center axis of the
workpiece.
▪ The operation produces external cylindrical surfaces for parts such as shafts and axles.
▪ Example: Turning is used to create cylindrical components like bolts, shafts, pulleys, and
hydraulic cylinders.
▪ Applications: Automotive, aerospace, machinery, and electronics for producing
cylindrical parts with high precision and surface finish.

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 Turning Machine (Lathe)
ii.Drilling:
▪ The drilling operation is used to create holes, generally using a drill press using a
rotating cutting tool called a drill bit.
❖ Tool: Rotating Cutting Tool (drill bit)
▪ The drill bit is fed into the workpiece, and as it rotates, it cuts away material to create a
hole with a circular cross-section.
▪ The drill press can also be used to improve the surface finish of a hole by reaming and it
can also be used to thread a hole, known as tapping.
▪ Example: Drilling is employed in various applications such as creating holes for
fasteners in metal structures, drilling holes for wiring in electrical panels, and producing
holes for plumbing fixtures.
▪ Applications: Drilling is essential in industries such as construction, manufacturing,
aerospace, automotive, and electronics for creating holes of various sizes and depths in
different materials.

Drilling Machine Milling Machine

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iii.Milling:
▪ Milling uses multiple tooth cutters to generate flat surfaces and complex surfaces. It
uses rotary cutters to create complex shapes and features.
❖ Tool: Rotary Cutters
▪ In milling, the workpiece is secured to a machine table, and a rotating cutter with multiple
cutting edges removes material as it moves across the workpiece in various directions.
▪ The milling machine is classified as either a Horizontal or Vertical machine.
i. On a Vertical milling machine,
❖ Center axis of the cutter is perpendicular to the cutting table.
ii. On a Horizontal milling machine,
❖ Center axis of the cutter is Parallel to the cutting table.
▪ Milling machines, with the multiple tooth cutters, have high metal removal rates.
▪ Example: Gears, slots, pockets, and contours on flat or curved surfaces.
▪ Applications: automotive, aerospace, tool and die making, mold making, and precision
engineering for manufacturing parts with intricate geometries and tight tolerances.
iv.Shaping:
▪ The shaper is a relatively simple tool. The shaper is used mainly for facing but can also
create slots, steps, and dovetails using a single-point cutting tool to create flat surfaces
or contours.
❖ Tool: Single-Point Cutting Tool
▪ The workpiece is held in a vice while the ram, which carries the tool, slides back and
forth in equal strokes to the desired stroke length.
▪ In shaping, the workpiece is mounted on a machine table and a reciprocating cutting tool
moves across the workpiece, removing material to produce flat surfaces, grooves, or
complex profiles.
▪ The tool cuts in one direction only, but the return stroke is faster than the cutting stroke to
reduce idle time.
▪ Example: Create flat surfaces, keyways, splines, and irregular shapes on components
such as gears, cams, and tooling.
▪ Applications: Manufacturing, tool and die making, and repair workshops for producing
components with specific surface profiles and geometries.

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 Shaping Machine

Introduction to CNC machines

Short answer questions:
22. What is CNC machining?
Computer Numerical Control (CNC) is one in which the functions and motions of a
machine tool are controlled using a prepared program containing coded alphanumeric data.
CNC can control the workpiece or tool's motions, input parameters such as feed, depth of
cut, speed, and functions such as turning the spindle on/off and turning coolant on/off.
23. List the advantages of CNC.
(1) high accuracy in manufacturing, (2) short production time, (3) greater
manufacturing flexibility, (4) simpler fixturing, (5) contour machining (2 to 5
-axis machining), (6) reduced human error.
24. List the disadvantages of CNC.
The drawbacks include high cost, maintenance, and the requirement of skilled part
programmers.
25. What are the essential components of CNC? 2M
CNC system consists of three basic components.
1.Part program 2. Machine Control Unit (MCU) 3. Machine tool (lathe, drill press, milling
machine etc).

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 Descriptive Questions
26. Explain the CNC machining process in detail. Give advantages of CNC.
Introduction to CNC Machines
▪ Computer Numerical Control (CNC) is one in which the functions and motions of a machine tool are
controlled using a prepared program containing coded alphanumeric data.
▪ CNC can control the workpiece or tool's motions, input parameters such as feed, depth of cut,
speed, and functions such as turning the spindle on/off and turning coolant on/off.
▪ CNC machines are automated systems where the movements and functions of the machine tools are
controlled by computerized programs. These programs are generated based on digital design
models and instructions, allowing for precise and repeatable machining operations.
▪ In CNC machines, the operator inputs design specifications into computer software, which generates
a code (typically G-code) containing instructions for the machine. This code dictates the
movements, speeds, and tool operations necessary to produce the desired part.
Advantages of CNC are
• High Accuracy In Manufacturing,
• Short Production Time,
• Greater Manufacturing Flexibility,
• Simpler Fixturing,
• Contour Machining (2 To 5 -Axis Machining),
• Reduced Human Error.
Limitations: High cost, maintenance, and the requirement of skilled part programmers.
Elements of a CNC: A CNC system consists of three basic components.
1. Part program
2. Machine Control Unit (MCU)
3. Machine tool (lathe, drill press, milling machine etc).
▪ Part Program
▪ The part program is a detailed set of commands to be followed by the machine tool.
▪ Each command specifies a
• Position in the Cartesian coordinate system (x,y,z)
• Motion (workpiece travel or cutting tool travel),
• Machining parameters and on/off function.
▪ The part program is written manually or using computer-assisted language such as APT
(Automated Programming Tool).
▪ The operator inputs design specifications into CAD/CAM software, which generates the
necessary toolpaths and G-code instructions for the CNC milling machine to follow
▪ Machine Control Unit:
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▪ The machine control unit (MCU) is a microcomputer that stores the program and executes the
commands into actions by the machine tool.
▪ This control unit interprets the program instructions and sends signals to the motors and
actuators to execute the machining operations.
▪ The MCU consists of two main units:
a. The data processing unit (DPU)
b. The control loops unit (CLU).
❖ This DPU and CLU software includes control system software, calculation algorithms,
translation software that converts the part program into a usable format for the
MCU, interpolation algorithm to achieve smooth cutter motion, and editing of the part
program (in case of errors and changes).
❖ Example:
❖ Few CNC Machines:
• CNC Milling , CNC Drilling Machines,
• CNC Plasma Cutting Machines, CNC grinders,
• CNC Lathes, CNC Bending Machines,
• CNC Laser Cutters, CNC Water-jet Cutters,
• CNC Robot, and 3D Printers.

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Applications:
❖ Highly automated machine tools such as the turning centre and machining centre,
which change the cutting tools automatically under CNC control have been developed.
❖ In the non-machine tool category, CNC applications include welding machines (arc and
resistance), coordinate measuring machines, electronic assembly, tape laying, and
filament winding machines for composites.
Applications:
i. Tool and Die Making: Molds, dies, jigs, and fixtures for manufacturing processes.
ii. Machine Tool: Lathes, drill presses, milling machines, grinding units, laser, sheet-metal press
working machines, tube bending machines, etc.
iii. Automotive: Engine components, chassis parts, and body panels with high precision.
iv. Aerospace: Turbine blades, structural parts, and landing gear components.
v. Medical: Medical implants, surgical instruments, and precision medical devices.
vi. Electronics: Circuit boards, housings, connectors, and other electronic components.
vii. Prototyping and Rapid Manufacturing: Rapid production of prototypes and low-volume
production runs for product development and testing.

27. Discuss the types of CNC’s and enlist the profitable applications of CNC?
• CNC Milling , CNC Drilling Machines,
• CNC Plasma Cutting Machines, CNC grinders,
• CNC Lathes, CNC Bending Machines,
• CNC Laser Cutters, CNC Water-jet Cutters,
• CNC Robot, and 3D Printers.
Short answer questions:
28. What is 3D printing? 2M
3D printing is an additive manufacturing technique. In this process, the product is
manufactured by adding layer by layer. Various 3D printing processes are Stereo
lithography, Selective laser sintering, and Fused Deposition modeling.
29. What are the essential components of 3D printing? 2M
Controller Board, Filament, Frame, Stepper Motors, Belts, Power Supply Unit
(PSU),Print Bed, Print Bed Surface, Print Head, Feeder System
30. What are the steps in 3D printing? 2M
Modeling, slicing, printing, and post-processing
31. What materials are processed by 3D printing?
Acrylonitrile Butadiene Styrene (ABS) Plastic material, powders, resins, metal and
carbon fiber.
 Descriptive Questions
32. What are the steps in 3D printing? Explain.
Additive Manufacturing - 3D Printing
▪ In contrast to Traditional Manufacturing, 3D printing process can create objects directly by
adding material layer by layer in a variety of ways, depending on the technology used.
▪ 3D Printing can be done in a variety of processes under computer control like
• Material is Deposited,
• Material is joined or Solidified, with the material being added together
(such as plastics, liquids or powder grains), typically layer by layer.
▪ Components can be designed specifically to avoid assembly requirements with intricate
geometry and complex features created at no extra cost.
▪ 3D printing is also emerging as an energy efficient technology that can provide environmental
efficiencies in terms of both the manufacturing process itself, utilizing up to 90% of standard
materials and throughout the product’s operating life through lighter and stronger design.
The steps involved in 3D printing typically include the following:
1. 3D Design
2. Slicing
3. Material Selection & Preparation of 3D Printer
4. Printing
5. Post-Processing (Optional)
6. Quality Control
1. 3D Design: The process starts with creating a digital 3D model of the object to be printed. This
can be done using Computer-Aided Design (CAD) software, or by scanning an existing object
using 3D scanning technology.
2. Slicing: The 3D model is then sliced into thin horizontal layers using slicing software. Further
these designs are converted into a file readable by a 3D printer. This software generates a set of
instructions (G-code) that guide the 3D printer on how to build each layer.
3. Material Selection & Preparation of 3D Printer: Choose the appropriate printing material
(such as plastic filament, resin, metal powder, etc.) based on the requirements of the object
being printed.
4. Printing: The 3D printer begins building the object layer by layer according to the instructions
provided by the slicing software. This process can take varying amounts of time depending on
the complexity and size of the object.
5. Post-Processing (Optional): After printing is complete, post-processing steps may be necessary
depending on the specific requirements of the object. This can include removing support
structures, smoothing the surface, or applying additional finishing touches.
 6. Quality Control: Inspect the printed object for any defects or inaccuracies. Depending on the
results, adjustments may need to be made to the printing parameters or design for future prints.
Types of 3D Printer:
• The different types of 3D printers each employ a different technology that processes different
materials in different ways.
▪ Example, some 3D printers process powdered materials (nylon, plastic,
ceramic, metal), which utilize a light/heat source to sinter/melt/fuse layers
of the powder together in the defined shape.
▪ Others process polymer resin materials and use a light/laser to solidify the
resin in ultra-thin layers.
▪ “Perhaps the most common and easily recognized process is deposition,
which is employed by most entry-level 3D printers.” This process extrudes
plastics, in filament form through a heated extruder to form layers and create
the predetermined shape.
• Because parts can be printed directly, it is possible to produce very
detailed and intricate objects, often with functionality built in and
negating the need for assembly.
The three commonly used 3D printing techniques are
i. Stereolithography (SLA)
ii. Selectie Laser Sintering (SLS)
iii. Fused Deposition Modeling. (FDM)
i. Stereolithography (SLA): (Vat polymerization Process)
• Stereolithography (SLA) is a attractive process in which 3D objects is created by building them
up layer by layer using a special liquid that turns liquid to solid when exposed to light.
• So, by pouring this type of Photosensitive liquid (photopolymer resin) in a reservoir tank &
cured by ultraviolet (UV) laser light to harden (selectively polymerize (i.e., solidify)) it to form
the shape as desired.
• Process can be repeated layer by layer to complete the entire object as designed.
 In vat polymerization, a vat or reservoir holds the liquid photopolymer resin. A platform is
submerged into the resin, and a UV light source, often a laser, is directed onto the surface of the resin
to solidify it according to the pattern of each layer of the 3D object being created. Once a layer is
solidified, the platform moves down slightly to allow for the next layer of resin to be exposed to the
light source. This process repeats layer by layer until the entire object is formed.
ii. Selective Laser Sintering (SLS):
• It is a powder-based additive manufacture technology that uses energy provided by the laser to
melt and fuse the powders and then stack layer by layer to form a printed part based on 3D
model data.

Selective Laser Sintering (SLS) Fused Deposition Modeling

iii. Fused Deposition Modeling (FDM):
• It is also known as Fused Filament Fabrication (FFF), is one of the most common methods of
3D printing.
• FDM printers extrude a plastic filament in a series of layers over a build plate to create a 3D
object.
Advantages:
• Design Freedom: Complex geometries & intricate designs (costly in traditional mfg.)
• Customization: Customized products tailored to needs and with high precision.
• Cost-Effectiveness: Less material waste compared to subtractive manufacturing
• Rapid Prototyping: Rapid prototyping & iteration, accelerate product development
• On-Demand Manufacturing: Small-batch manufacturing & reducing large inventories.
• Being Tool-Less Process: There is no need for molds, molds, dies, or fixtures or
tooling, resulting in lower setup costs and making manufacturing more accessible. So,
▪ Reduces Prohibitive costs. (As no High initial expensive molds)
▪ Reduces Lead times. (No machining, molds, Cutting – Secondary Operations)
 ▪ So, Rapid prototyping and iteration.(iterate designs quickly and cost-effectively
helps identify & resolve issues early in the development process,)
▪ Saving time & Cost. ( No secondary operations, so, minimize overhead expenses,
and possible of respond more efficiently to market demands).
Applications:
• Functional plastics, metals, ceramics and sand are routinely used for industrial prototyping
and production applications.
• There is also a growing number of entry level machines that have been adapted for
foodstuffs, such as sugar and chocolate.
• Prototyping: 3D printing is widely used in product development for creating prototypes and
proof-of-concept models.
• Manufacturing: It is increasingly being used for small-scale production of customized and
specialized parts, particularly in industries such as aerospace, automotive, and healthcare.
• Medical: 3D printing is used to produce patient-specific implants, prosthetics, and surgical
instruments, as well as for tissue engineering and bioprinting applications.
• Architecture and Construction: It is employed for creating architectural models, scale
prototypes, and even full-scale structures using concrete or other building materials.
• Education: 3D printing is used in educational settings to teach design, engineering, and
manufacturing concepts, allowing students to bring their ideas to life.

Smart Manufacturing
Short answer questions:
33. Define smart manufacturing.
Smart manufacturing is defined as “ Fully-integrated, collaborative manufacturing systems that
respond in real time to meet changing demands and conditions in the factory, in the supply network, and in
customer needs”.
34. What are the layers in smart manufacturing?
Ans Smart manufacturing consists of two basic layers, the manufacturing equipment
layer, and the cyber layer, linked by the interface. The manufacturing equipment has its
intelligence, while the cyber layer provides the system-wide intelligence.
35. With a schematic, explain smart manufacturing enterprise.
Smart manufacturing is defined as “Fully-integrated, collaborative manufacturing systems that
respond in real time to meet changing demands and conditions in the factory, in the supply
network, and in customer needs”.
Smart manufacturing integrates manufacturing assets of today and tomorrow with
• Sensors,
 • Computing Platforms,
• Communication Technology,
• Data-Intensive Modeling, Control, Simulation,
• Predictive Engineering.
Smart manufacturing utilises the concepts of the
• Cyber-Physical Systems,
• Internet Of Things (And Everything),
• Cloud Computing,
• Service Oriented Computing,
• Artificial Intelligence And Data science.
36. Once implemented, these overlapping concepts and technologies will make
manufacturing the hallmark of the next industrial revolution.
37. A general concept of a smart manufacturing enterprise is illustrated in Fig. The concept in
Fig. includes two basic layers,
• The manufacturing equipment layer
• The cyber layer, linked by the interface.
• The manufacturing equipment has its own intelligence, while the cyber layer provides the
system-wide intelligence.
38. Smart manufacturing has attracted the attention of industry, government organizations,
and academia. Various consortia and discussion groups have been formed to develop architectures,
roadmaps, standards, and research agendas.
39. The general concept of smart manufacturing systems in Fig. needs to be translated in
architectures that are quite specific. Efforts are under way to develop such architectures.

General concept of a smart manufacturing enterprise

 UNIT V Part-B
THERMAL ENGINEERING

1. What is the function of the boiler?

Answer: The steam generated is employed for the following purposes
✓ Used in steam turbines to develop electrical energy
✓ Used to run steam engines
✓ In the textile industries, sugar mills, or chemical industries as a cogeneration plant
✓ Heating the buildings in cold weather
✓ Producing hot water for hot water supply
2. Define fire tube boiler.
Answer: A fire tube boiler is a type of boiler in which the hot flue gases are present inside the tubes and
water surrounds them. They are low-pressure boilers. The operating pressure is about 25 bar. The steam
generation rate in a fire tube boiler is low, i.e., tonnes per hour.

3. Define water tube boiler.

Answer: In the water tube boiler water flows inside the tubes and the hot gases are outside the
tubes.
4. What are the boiler accessories?
Answer: The important boiler accessories are the economizer, air preheater and superheater,
feed pump, ejector, steam strap, etc.

5. Draw the PV diagram of the Otto cycle.

Answer:
6. Draw the TS diagram for the Diesel cycle.
Answer:

7. Write the applications of refrigeration

Answer: Refrigeration is a process that involves removing heat from a space, substance, or system to lower
its temperature. The primary goal of refrigeration is to maintain a lower temperature in a controlled
environment, such as a refrigerator or a cold storage room, to preserve food, extend the shelf life of
perishable items, or create a comfortable climate.

8. Explain the term “ton of refrigeration”

Answer: A ton of refrigeration (1 TR) is defined as the amount of heat, which is to be extracted from
one ton of water at 0 ℃ to convert into ice at 0 ℃ in 24 hours (1 day).
1 TR = 210 kJ/min = 3.5 kW

9. Compare Otto and Diesel cycles.

Answer:
The Otto cycle is used in gasoline engines and has a lower compression ratio, with heat added at constant
volume. The Diesel cycle is used in diesel engines and has a higher compression ratio, with heat added at
constant pressure. Diesel engines are more efficient but produce higher emissions, while gasoline engines
have lower emissions but are less efficient.
Diesel engines have a higher compression ratio than petrol engines because they use compression
ignition, require higher temperatures for fuel ignition, and benefit from better thermal efficiency and power
output.
10. Classify the Internal combustion engines.
Answer:
There are several possible ways to classify internal combustion engines.
By Number of Strokes
• Two Stroke Engine
• Four-stroke engine
By type of ignition:
• Compression-ignition engine
• Spark-ignition engine

11. Distinguish SI and CI Engine.

Answer: Spark ignition engine (SI Engine) works on an Otto cycle, in suction stroke Fuel and air is sucked
and compressed, and with the aid of a spark plug combustion is carried, and fuel is petrol.
A compression ignition engine (CI Engine) works on a Diesel cycle, in the suction stroke only air is sucked
and compressed, at the end of the compression stroke diesel is sprayed and self-ignition has happened. The
fuel used is Diesel.

12. Distinguish 2-stroke and 4-stroke engine.

Answer: The cycle is completed in 2 strokes in 2 stroke engines, whereas the cycle is completed in 4 strokes
in 4 stroke engines.

13. Why do diesel engines have a higher compression ratio compared to petrol engines?
Answer: Diesel engines have higher compression ratios for efficient compression-ignition combustion and to
achieve higher thermal efficiency, power output, fuel economy, and torque compared to petrol engines.

14. What is a hybrid vehicle?

Answer: A hybrid vehicle combines any two power (energy) sources. Possible combinations include
diesel/electric, gasoline/flywheel, and fuel cell (FC)/battery. Typically, one energy source is storage, and the
other is the conversion of fuel to energy. The combination of two power sources may support two separate
propulsion systems.

15. What are the main parts of electric vehicles?

Answer: Motor, Fuel Source, EV Batteries
Essay questions:
Working principle of Boilers
16. Explain the construction and working of a simple vertical boiler.
• A simple vertical boiler produces steam at a low pressure and in small quantities.
• It is therefore used for low power generation or at places with limited space.
• The construction of this type of boiler is showninFig.
Construction:
• It consists of a cylindrical shell surrounding an early cylindrical firebox.
• Firebox is slightly tapered towards the top to allow the ready passage steam to the surface.
• Firebox is fitted with two or more inclined cross tubes.
• Inclination provided to increase the heating surface and to improve the circulation of water.
• An uptake tube passes from the top of the firebox to the chimney.
• The handholes are provided opposite the end of each water tube for cleaning deposits.
• A manhole is provided at the top for a man to enter and clean the boiler.
• A mudhole is provided at the bottom of the shell to remove the mud that settles down. The
space between the boiler shell and the firebox is filled with water to heat.
Fire Tube Boiler Water Tube Boiler

Figure: Simple vertical boiler

Working:
• Fuel burns on the grate in the firebox.
• The resulting hot flue gases are allowed to pass around the cross tubes.
• The water surrounding the cylindrical firebox also receives heat by convection and radiation, thus
steam is produced.
• The water circulation in the boiler depends on the density difference in the water created by the
temperature difference in the water.
17. How are boilers classified? What are the Boiler mountings?
Answer:
Classification of Boilers
The different ways to classify the boilers areas follows
i. According to the location of the boiler shell axis
ii. According to the flow medium inside the tube
• According to the location of the boiler shell axis
• Horizontal: When the axis of the boiler shell is horizontal the boiler is
called a horizontal boiler.
Examples: Locomotive boiler, Babcock and Wilcox boiler,etc.
• Vertical: If the axis is vertical, the boiler is called a vertical boiler
Example: Simple vertical boiler Cochran boiler.
• According to the flow medium inside the tubes
▪ Firetube: The boilers in which hot flue gases are inside the tubes and water is
surrounding the tubes are called fire tube boilers.
o Example: Lancashire, locomotive, Cochran, and Cornish boilers
▪ Water tube boilers: When water is inside the tubes and the hot gases are outside,
the boiler is called water tube boiler.
o Example: Simple vertical boiler, Babcock and Wilcox boiler
Advantages and limitations of water tube and fire tube boilers
Water tube boilers:
o Water tube boilers have advantages such as higher efficiency, faster steam
generation, compact design, better water circulation, ability to handle high pressures,
and flexibility in design. However, they also have limitations, including higher initial
costs, complex maintenance, susceptibility to freezing, water quality requirements,
and limited capacity.
Fire tube boilers:
Fire tube boilers have advantages such as lower initial cost, ease of maintenance, quick steam production,
compact size, and lower water quality requirements. However, they also have limitations such as lower
efficiency, limited pressure capacity, less responsiveness to load

Comparison between fire tube boilers and water tube boilers

Fire tube boiler Water tube boiler

In this boiler, the hot flue gases are present The water is present inside the tubes and the hot flue
inside the tubes and water surrounds them gases surround them
They are low-pressure boilers. The operating They are high-pressure boilers and the operating
pressure is about 25 bar pressure is about 165 bar
The steam generation rate in fire tube boiler is Steam generation rate in water tube boiler is high
low, i.e. tonne per hour i.e. 450 tonnes per hour
The transportation and erection of this type of The transportation and erection are easy as its
boiler is difficult parts can be separated
It can work on fluctuating loads for a shorter It works on fluctuating loads all the times
period
The direction of water circulation in fire tube The direction of water circulation in the water tube
boiler is not well-defined boiler is well defined i.e. a definite path is
provided for the circulation of water
o changes, thermal stress susceptibility, and limited steam quality.
Boiler Accessories
These are the fittings, which are mounted on the boiler for satisfactory functioning, efficient working,
easy maintenance, and safety of the Boilers. Important mountings which are generally fitted on a boiler are
given below: Boiler Mountings - Important boiler mountings are given below:
• Water level indicator
• Pressure gauge
• Safety valves
• Stop valve
• Blow off cock
• Feed check valve
18. State advantages and limitations of water tube and Fire tube boilers.
Answer:
Water tube boilers:
Water tube boilers have advantages such as higher efficiency, faster steam generation, compact
design, better water circulation, ability to handle high pressures, and flexibility in design.
However, they also have limitations, including higher initial costs, complex maintenance,
susceptibility to freezing, water quality requirements, and limited capacity.
Fire tube boilers:
Fire tube boilers have advantages such as lower initial cost, ease of maintenance, quick steam
 production, compact size, and lower water quality requirements. However, they also have limitations
such as lower efficiency, limited pressure capacity, less responsiveness to load changes, thermal
stress susceptibility, and limited steam quality.

Otto cycle, Diesel cycle, Refrigeration and air-conditioning cycles

18a) Comparison Otto and Diesel cycles.

The Otto cycle is used in gasoline engines and has a lower compression ratio, with heat added at constant
volume. The Diesel cycle is used in diesel engines and has a higher compression ratio, with heat added at
constant pressure. Diesel engines are more efficient but produce higher emissions, while gasoline engines
have lower emissions but are less efficient.
Diesel engines have a higher compression ratio than petrol engines because they use compression
ignition, require higher temperatures for fuel ignition, and benefit from better thermal efficiency and power
output.
Aspect Otto Cycle (Gasoline Engines) Diesel Cycle (Diesel Engines)
Type of Engine Gasoline (Petrol) Engine Diesel Engine
Compression Ratio Lower Higher
Heat Addition Constant Volume (Spark Ignition) Constant Pressure (Compression Ignition)
Ignition Spark Plug Compression Ignition (Fuel injected into
hot, compressed air)
Thermal Efficiency Generally lower Generally higher
Power Output Generally lower Generally higher
Emissions Lower (NOx and particulate matter) Higher (NOx and particulate matter)

19. Draw the PV and TS diagram of the Otto Cycle and explain each process.
Answer:
• The main drawback of the Carnot cycle is its impracticability due to high pressure and high-
volume ratios employed with comparatively low mean effective pressure.
• Nicolaus Otto (1876) proposed a constant-volume heat addition cycle which forms the basis for
the working of today’s spark-ignition engines.
• The cycle is shown on p-V and T -s diagrams in Fig.2.5(a) and 2.5(b) respectively.
• When the engine is working on full throttle, the processes 0→1 and 1→0 on the p-V diagram
represent suction and exhaust processes and their effect is nullified.
• The process 1→2 represents isentropic compression of the air when the piston moves from
bottom dead centre to top dead center.
• During the process 2→3 heat is supplied reversibly at constant volume. This process
 corresponds to spark-ignition and combustion in the actual engine.
• The processes 3→4 and 4→1 represent isentropic expansion and constant volume heat rejection
respectively.
• Otto cycle has a compression ratio range of 6:1 to 12:1, which is less than the compression ratio
of the Diesel cycle 16:1 to 22:1.
• An Otto cycle works in the following way:

Entropy: A measure of Disorder or Randomness

Adiabatic: No Heat Transfer
Isentropic: No change in Entropy (ideal adabatic Process – i.e, change without heat transfr)

20. Derive an expression to find the efficiency of an Otto cycle.

Answer:
21. Draw the PV and TS diagram of the diesel Cycle and explain each process.
Answer:
The Diesel cycle is different from the Otto cycle (typical for gasoline engines) primarily in the combustion
process. In the Diesel cycle, combustion occurs at constant volume, whereas in the Otto cycle, combustion
occurs at constant pressure. The high compression ratio of diesel engines contributes to their higher thermal
efficiency compared to gasoline engines.
• The Diesel cycle is a combustion process of a reciprocating internal combustion engine.

• In it, fuel is ignited by heat generated during the compression of air in the combustion
chamber, into which fuel is then injected.

• Diesel engines are used in aircraft, automobiles, power generation, diesel–electric

locomotives, and both surface ships and submarines.
 i. Compression (Process 1-2): The air is drawn into the cylinder during the intake stroke, and then the
piston compresses the air adiabatically (without heat transfer) during the compression stroke (Process
1-2). This compression raises the temperature and pressure of the air.
ii. Combustion (Process 2-3): Once the air is compressed, fuel is injected directly into the highly
compressed air. The fuel spontaneously ignites due to the high temperature of the compressed air.
This process is known as constant volume combustion or isochoric combustion. The pressure and
temperature increase dramatically during this phase (Process 2-3).
iii. Expansion (Process 3-4): The high-pressure, high-temperature gases resulting from combustion
expand and do work on the piston during the power stroke. This expansion is adiabatic and is
represented by Process 3-4.
iv. Exhaust (Process 4-1): In the exhaust stroke, the piston moves back up the cylinder, expelling the
remaining exhaust gases. This is a constant volume process, as the exhaust valve is open, and the
pressure drops to the initial level (Process 4-1).
The Diesel cycle is different from the Otto cycle (typical for gasoline engines) primarily in the combustion
process. In the Diesel cycle, combustion occurs at constant volume, whereas in the Otto cycle, combustion
occurs at constant pressure. The high compression ratio of diesel engines contributes to their higher thermal
efficiency compared to gasoline engines.
The maximum thermal efficiency of a Diesel cycle is dependent on the compression ratio and the cut-off
ratio. It has the following formula under cold air standard analysis.
Thermal efficiency can be expressed as,

Whereas, r is the Compression ratio

ρ is the cutoff ratio

22. Explain the workings of the refrigeration cycle with the PV and TS diagram.
Answer:
Refrigeration Cycle Working
A refrigerator works on the refrigeration cycle

The refrigerant enters the compress ion chamber in a vapor state.

1. Compression
2. Condensation
3. Throttling Process
4. Evaporation Process

1) Adiabatic Compression (1 to 2): The compressor has a piston that moves up and down inside the
compression chamber. As the refrigerant enters the compression chamber, the inlet and outlet valves close,
and the piston compresses the refrigerant. Due to the compression process, the temperature of the vapor

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refrigerant increases from T1 to T2, and pressure increases from P1 to P2. Line 1 to 2 of the above-given
graph represents this process.
2) Condensation Process (2 to 3): Line 2 to 3 represents the condensation process. As the compressed
refrigerant enters the condenser, the condenser condenses the compressed vapor refrigerant at constant
pressure.
During the condensation process, the compressed refrigerant transfers its heat to the hot reservoir.
Dueto this heat transfer process, the vapor refrigerant converts into a liquid state. During this process,
theenthalpy and volume of the refrigerant decrease
However, the pressure of the refrigerant remains the same during this whole process. After this
process, the liquid refrigerant is transferred into the throttling valve for further processing.
3) Throttling Process (3 to 4):
• After the condensation process, the liquid refrigerant pushes into a throttling valve.
• As the refrigerant enters into this valve, it expands; due to that, the pressure and temperature of the
liquid refrigerant reduce (As you can see in the above graph).
• However, the volume and enthalpy of the refrigerant increase.

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4) Evaporation Process (4 to 1):
• Line 4 to 1 of the above-given PV diagram and TS diagram of the refrigeration cycle represent this
process.
• The evaporator is connected to a cold reservoir.
• As the low-pressure and low-temperature liquid refrigerant enters the evaporator, the refrigerant
absorbs heat from the cold reservoir and converts it into a vapor state.
• During this process, the volume and enthalpy of the refrigerant increase but its pressure and
temperature remain constant.

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23. What are the industrial applications of air conditioning?
Answer:
Air-Conditioning:
• Air conditioning is a technology that maintains comfortable temperature and humidity of an enclosed
space to make it more comfortable.
• Applications: Widely used in homes, offices, vehicles, and industrial spaces to create pleasant and
controlled climates.
• Air conditioning is crucial for various industries, with common applications including:
• Manufacturing Plants: It helps maintain optimal conditions for machinery and workers, controlling
humidity, temperature, and air quality.
• Data Centers: Air conditioning ensures precise temperature and humidity levels to prevent equipment
overheating and failures.
• Food Processing Facilities: It controls temperature and humidity to preserve food quality and safety
during processing and storage.
• Pharmaceutical Industry: Air conditioning maintains cleanroom environments for safe and effective
pharmaceutical production.
• Hospitals and Healthcare Facilities: It creates a comfortable and hygienic environment for patients,
staff, and medical equipment.
• Commercial Buildings: Air conditioning provides a comfortable environment for occupants and
customers in offices, malls, and hotels.
• Automobile Industry: It maintains comfortable working conditions for workers and controls
temperature and humidity in critical areas like paint booths.
• Agricultural Storage: Air conditioning maintains optimal temperature and humidity in cold storage
warehouses and refrigerated trucks for storing perishable goods.
• Refrigeration Cycles: Also utilizes the Vapor Compression Cycle but is tailored to regulate both
temperature and humidity.
24. Define one ton of refrigeration. Explain the properties of ideal refrigerants.
Answer:
Ton of refrigeration
A ton of refrigeration (1 TR) is defined as the amount of heat, which is to be extracted from one ton of
water at 0 ℃ to convert into ice at 0 ℃ in 24 hours (1 day).
1 TR = 210 kJ/min = 3.5 kW
Ideal refrigerants properties
Ideal refrigerants possess certain properties that make them suitable for use in refrigeration systems. These
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properties include:
Low boiling point: Ideal refrigerants have a low boiling point, allowing them to evaporate easily at low
temperatures and absorb heat from the surroundings.
High latent heat of vaporization: Ideal refrigerants have a high latent heat of vaporization, meaning they
can absorb a large amount of heat when they evaporate, making them efficient in cooling applications.
Non-toxic and non-flammable: Ideal refrigerants are non-toxic and non-flammable to ensure safety in
handling and use.
Chemically stable: Ideal refrigerants are chemically stable under normal operating conditions to prevent
degradation and ensure long-term performance.
Compatible with materials: Ideal refrigerants are compatible with the materials used in refrigeration
systems to prevent corrosion and damage.
Environmentally friendly: Ideal refrigerants have low global warming potential (GWP) and ozone
depletion potential (ODP) to minimize their impact on the environment.
Efficient thermodynamic properties: Ideal refrigerants have efficient thermodynamic properties, such as a
high coefficient of performance (COP), to ensure energy-efficient operation of refrigeration systems.
Readily available and cost-effective: Ideal refrigerants are readily available and cost-effective to ensure
practicality and affordability in refrigeration applications.
IC engines, 2-stroke and 4-stroke engines, SI/CI Engines
25. Compare two-stroke and four-stroke internal combustion engines.
Answer:
The main difference between a two-stroke engine and the four-stroke engine is given
below:
Characteristic Two-Stroke Engine Four-Stroke Engine
Crankshaft Revolution per Power One Two
Cycle
Piston Stroke per Working Cycle Two Four
Fuel Suction and Discharge Inlet and Outlet Ports Inlet and Outlet Valves
Mechanism
Thermal Efficiency Low High
Smoke Emission More Less
Lubricating Oil Requirement More Less
Wear & Tear Issues High Lower
Manufacturing Cost Low (Cheaper and High (Due to Extra Rotating
Simple) Parts)

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26. With a neat sketch, explain the working of the four Stoke petrol engines.
Answer:
A four-stroke engine is an IC engine that completes a power cycle after the completion of four-piston
strokes. In this engine, intake, compression, power, and exhaust processes occur in different strokes. This
engine completes two revolutions of the crankshaft after the completion of one power cycle. It has a quiet
operation.
Important 4 Process to take place to generate Power:
1. Intake
2. Compression
3. Expansion
4. Exhaust

4 Stroke Engine::
“4 Processes” happens in “4 Stroke”

For Every 1 Stroke Piston => 180º of Crank Shaft Rotation

4 Stroke:
For completion of one thermodynamic cycle (4 stroke):
 Crank Shaft rotates 720º angle
(2 Revolutions)
 = 4 * 180º = 720º

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1. Intake
❖ Carburetors : Air + Fuel mixed in Proper Ratio and sent inside Chamber
❖ Crank Moves to Down (180º): Vacuum Creation < 1 bar due to Pressure Difference b/n
Atmosphere and Inside chamber.
❖ Suction Valve Opens --- Charge (Air + Fuel) enters into the cylinder.
• The piston moves downward inside the cylinder.
• The intake valve opens, allowing the air–fuel mixture (in a gasoline
engine) or just air (in a diesel engine) to enter the combustion chamber.
• This process ensures the cylinder has the proper charge of air or air–fuel
mix needed for combustion.
2. Compression
❖ Crank Moves to Up (360º): Compression of Charge (Air + Fuel) happens
❖ i.e., Volume ↓ ↓ ::: Pressure ↑ ↑ ::: Temperature ↑ ↑
❖ At the End of Compression stroke – Spark Releases from Spark Plug to ignite the Charge
(Air + Fuel)

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 • Once the intake valve closes, the piston moves upward, compressing the
air–fuel mixture in the combustion chamber.
• The compression raises both the temperature and pressure of the trapped
mixture, making it more reactive and ready for ignition.
• In gasoline engines, a spark plug is used to ignite the mixture; in diesel
engines, combustion is initiated by the high temperature of the
compressed air.
3. Expansion (Power Stroke)
Power Stroke:
❖ Power is Generated during Expansion & move the Piston down
❖ Crank Moves to Down (540º)
• The compressed mixture is ignited (by spark in gasoline engines or by
heat of compression in diesel engines).
• Rapid combustion forces the piston downward with significant force,
converting chemical energy into mechanical energy.
• This downward stroke is what produces the engine’s power, driving the
crankshaft and ultimately powering the vehicle or machinery.
4. Exhaust
❖ Exhaust valve open due to Pressure Difference b/n inside Chamber & Atmosphere.
❖ Crank Moves to Up (720º): Gases released into Atmosphere through Exhaust valve.
• After the power stroke, the piston moves upward again.
• The exhaust valve opens, expelling the burned gases (combustion
byproducts) out of the cylinder through the exhaust manifold.
• This readies the cylinder for the next cycle, beginning again with the
intake stroke.
Each of these four strokes is essential for the continuous operation of the engine, providing the mechanical
power needed to propel a vehicle or run machinery.

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27. Explain the working of the two-stroke petrol engine with a neat sketch.
2 Stroke Engine::
“4 Processes” happens in “2 Strokes”
Important 4 Process to take place to generate Power:
1. Intake
2. Compression
3. Expansion
4. Exhaust
For Every 1 Stroke Piston => 180º of Crank Shaft Rotation
2 Stroke:
For completion of one thermodynamic cycle (2 stroke):
 Crank Shaft rotates 360º angle
(1 Revolutions)
 = 2 * 180º = 260º

A 2-stroke engine is a reciprocating engine that uses two strokes of the piston to complete power. In this
engine, intake and compression processes are completed in the first stroke of the piston, while power and
exhaust processes occur in the second stroke. It completes one revolution of the crankshaft after the
completion of one power cycle. These have low weight.

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 1. Intake & Compression:
• Crank Moves to Up: (Air+Fuel) → comes inside as Piston moves from BDC to
TDC
• And Compression of (Air+Fuel) charge -
• Carburetors : Air + Fuel mixed in Proper Ratio and sent inside Chamber
• Crank Moves to Down (180º): Vacuum Creation < 1 bar due to Pressure
Difference b/n Atmosphere and Inside chamber.
• Suction Valve Opens --- Charge (Air + Fuel) enters into the cylinder.

2. Power and Exhaust:

• Crank Moves to Up (360º): Compression of Charge (Air + Fuel) happens
• i.e., Volume ↓ ↓ ::: Pressure ↑ ↑ ::: Temperature ↑ ↑
• At the End of Compression stroke – Spark Releases from Spark Plug to ignite the
Charge (Air + Fuel)
• Power and exhaust processes occur in the second stroke.
• One revolution of the crankshaft for the completion of one power cycle

27a) Compare SI and CI Engine:

Spark Ignition (SI)/ Compression Ignition (CI) Engines
• SI engine is known or called Spark Ignition engine. In this engine, the combustion of fuel is done by
Spark Plug.
• CI engine is called a Compression Ignition engine. In this engine, the combustion of fuel is done by
injection of fuel into the hot compressed air.
Differences between SI Engine and CI Engine
S. SI Engine CI Engine
No. Inlet: Air + Fuel Inlet: Only Air
1. Known as the Spark Ignition Engine Known as the Compression Ignition Engine
2. Fuel: Gasoline or Petrol Fuel: Diesel
3. Self Ignition of Petrol: 250°C Self Ignition of Diesel: 210°C
4. Compression Ratio: 6 to 12 Compression Ratio: High, around 16 to 22
5. Light in weight due to low pressure Heavy in weight due to high pressure
6. Low vibration and noise More vibration and noise
7. Works on the Otto cycle Works on the Diesel cycle
8. Higher speed Lower speed
9. Thermal efficiency: Low or average Thermal efficiency: High
10. Air and fuel used during intake process Only air used during intake process
11. Also called a constant volume cycle Called a constant pressure cycle
12. Petrol fuel has a high self-ignition Diesel fuel has a self-ignition temperature but lower
temperature
13. Homogeneous mixture of fuel Heterogeneous mixture of fuel
14. Fitted with carburetor and spark plug Fitted with injection or fuel injected pump
15. Temperature range: 250 to 300°C Temperature: 600 to 700°C

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Components of Electric and Hybrid Vehicles
28. What are the essential components of Electric Vehicles? Or List the components of electric vehicles?
Explain.
Answer:
Electric Vehicles
• Introduction: An electric vehicle, also called an electric drive vehicle, uses one or more electric
motors or traction motors for propulsion.
• An electric vehicle may be powered through a collector system by electricity from off-vehicle
sources, or may be self-contained with a battery, solar panels, or a generator to convert fuel to
electricity.
• EVs include road and rail vehicles, surface and underwater vessels, electric aircraft, and electric
spacecraft.
• EVs first came into existence in the mid-19th century when electricity was among the preferred
methods for motor vehicle propulsion, providing a level of comfort and ease of operation that could
not be achieved by the gasoline cars of the time.
• The internal combustion engine has been the dominant propulsion method for motor vehicles for
almost 100 years, but electric power has remained commonplace in other vehicle types, such as trains
and smaller vehicles of all types.
• In the 21st century, EVs saw a resurgence due to technological developments and an increased focus
on renewable energy.

Parts of an Electric Vehicle:

• Electric vehicles have no engine, no radiator, no carburetor, and no spark plugs.
• Where an engine normally would be, some EVs have a front trunk.
• The empty space also adds safety to an electric vehicle, giving it a larger crumple zone better able to
absorb force in collisions.
• EVs may function differently from traditional vehicles, but they have a similar set of systems:
1. EV Batteries
2. Motor
3. Fuel Source (Charging System)
1. Battery: The battery pack is the heart of an electric vehicle. It stores electrical energy that powers the
vehicle's electric motor. Battery packs usually consist of numerous lithium-ion cells arranged in
modules or packs. The capacity and chemistry of the battery determine the range and performance of
the EV.

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 2. Electric Motor: Electric vehicles use an electric motor instead of an internal combustion engine to
generate motion. The electric motor converts electrical energy from the battery into mechanical
energy to drive the vehicle. There are various types of electric motors, including AC induction
motors, permanent magnet motors, and brushless DC motors.
3. Charging System: The charging system comprises components that enable the EV to be charged
from an external power source. This includes the onboard charger, which converts AC power from
the grid into DC power to charge the battery, as well as the charging port and associated connectors.
4. Thermal Management System: Electric vehicles require a thermal management system to regulate
the temperature of the battery pack, electric motor, and other critical components. This system helps
maintain optimal operating temperatures to maximize efficiency, prolong battery life, and ensure safe
operation.
5. Drive Train: The drive train transfers power from the electric motor to the wheels, enabling the
vehicle to move. In most EVs, the drive train includes a transmission or gearbox that adjusts the
speed and torque of the motor to meet the driving conditions.
6. Vehicle Control Unit (VCU): The VCU acts as the brain of the electric vehicle, coordinating the
operation of various subsystems, including the electric motor, battery management system, and safety
features. It controls functions such as acceleration, braking, and energy management to optimize
performance, efficiency, and safety.

29. What are the fundamental components of Hybrid Vehicles (HVs)?

Answer:
A hybrid vehicle combines any two power (energy) sources. Possible combinations include diesel/electric,
gasoline/flywheel, and fuel cell (FC)/battery. Typically, one energy source is storage, and the other is
conversion of a fuel to energy. The combination of two power sources may support two separate propulsion
systems. Thus, to be a True hybrid, the vehicle must have at least two modes of propulsion. For example, a
truck that uses a diesel to drive a generator, which in turn drives several electrical motors for all-wheel drive,
is not a hybrid. But if the truck has electrical energy storage to provide a second mode, which is electrical
assists, then it is a hybrid Vehicle. These two power sources may be paired in series, meaning that the gas
engine charges the batteries of an electric motor that powers the car, or in parallel, with both mechanisms
driving the car directly.
• HEV is formed by merging components from pure electrical vehicle & pure gasoline vehicle.
• The Electric Vehicle (EV) has an M/G which allows regenerative braking for an EV; the M/G
installed in the HEV enables regenerative braking.
• For the HEV, the M/G is tucked directly behind the engine.

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• In Honda hybrids, the M/G is connected directly to the engine.
• The transmission appears next in line.
• This arrangement has two torque producers; the M/G in motor mode, M-mode, and the
gasoline engine.
• The battery and M/G are connected electrically.

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 SUBJECT : BCME
UNIT VI Part-A POWER PLANTS
Short Answer Questions

1. What are the advantages of a steam power plant?

Answer:
• Less initial cost as compared to other power generating stations.
• It requires less land as compared to hydropower plants.
• The fuel (i.e. coal) is cheaper.
• The cost of generation is lesser than that of diesel power plants.

2. Give the basic components of a steam power plant.

Answer: Boiler, feed pump, turbine, condenser, cooling tower, generator.

3. Write the names of different types of power plants.

Answer: The major power plants are,
1. Steam power plant
2. Diesel power plant
3. Hydroelectric power plant
4. Nuclear power plant

4. State the importance of power plants.

Answer: Power plants are essential for modern life, providing the electricity needed for
essential services, economic activities, and technological advancements.

5. Name the major components of a Diesel Engine.

Answer: Compressor, pump, fuel injector, Diesel engine, generator

6. List out the advantages of a Diesel Power Plant.

Answer:
o The layout of a diesel power plant is quite simple.
o It requires less space because the number and size of its auxiliary equipment is
small.
o Diesel power plant can be started quickly and it can pick up the load in a short
time.
o It requires less water for cooling.

7. State the advantages of Hydro Electric Power Plant?

Answer:
Advantages of Hydroelectric Power Plant
• Renewable energy source
• Low operating costs
 • Minimal greenhouse gas emissions
• Reliable and flexible
• Long lifespan
• Flood control and water management benefits
8. What is the function of the Surge tank?
Answer:
The use of the surge tank is to avoid water hammering in the penstock. The water
hammer is the sudden rise in pressure in the penstock due to the shutting off of the
water to the turbine. This sudden rise in pressure is rapidly destroyed by the rise of the
water in the surge tank otherwise it may damage or burst the penstock.

9. What is the function of Penstock?

Answer:
Inlet waterways are the passages, through the Penstocks water is conveyed to the
turbines from the dam. Tunnels are of two types: pressure type and non-pressure type.
The pressure type enables the fall to be utilized for power production and these are
usually lined with steel or concrete to prevent leakages and friction losses. The non-
pressure type tunnel acts as a channel.

10. What are the essential components of a nuclear reactor?

Answer: 1. Nuclear Fuel, 2. Moderator, 3. Control Rods, 4. Reflector, 5. Reactors Vessel,
6. Biological Shielding, 7. Coolant.

11. Write the advantages of a Nuclear Power Plant?

Answer: Carbon-free electricity, High power output, Reliable energy source.

ESSAY QUESTIONS

Working principle of Steam power plants

1. Explain the working of a thermal power plant with a neat sketch. (or) Describe the
working principle of steam power plants.
Answer:
A steam power plant is a facility that generates electricity by converting heat energy into mechanical
energy using steam as the working fluid.
Parts:
1. Boiler: Generates steam by heating water using a fuel source.
2. Turbine: Converts the pressure energy of steam into mechanical energy.
3. Generator: Converts mechanical energy from the turbine into electrical energy.
4. Condenser: Condenses steam back into water for reuse in the boiler.
5. Feedwater Pump: Pumps water from the condenser to the boiler.
6. Cooling Tower: Cools the condenser water before recycling it back to the condenser.
 • In a steam power plant, fuel such as coal, natural gas, or nuclear material is burned in the
boiler to produce high-pressure steam.
• This steam is then directed into a turbine, causing it to spin. The spinning turbine is
connected to a generator, which converts the mechanical energy into electrical energy.
• After passing through the turbine, the steam is condensed back into water in the
condenser and returned to the boiler to repeat the cycle.
Working:
1. Fuel combustion produces heat, which boils water in the boiler to produce high-pressure steam.
2. The high-pressure steam is directed into a turbine, causing it to rotate.
3. The rotating turbine is connected to a generator, which produces electricity.
4. The steam exits the turbine and enters a condenser, where it condenses into water.
5. The condensed water is pumped back into the boiler, and the cycle repeats.
Steps involved in the operation of a steam power plant:
1. Fuel combustion
2. Steam generation
 3. Turbine operation
4. Generator operation
5. Electricity generation
6. Condensation
7. Water recycling
8. Heat rejection
1. Fuel Combustion:
• The process begins with the combustion of fuel, such as coal, natural gas, or nuclear
material, in the boiler furnace.
• The heat generated from the combustion raises the temperature of water to produce
steam.
2. Steam Generation:
• The high-temperature steam produced in the boiler is collected in the steam drum.
• The steam is then directed through pipes to the turbine.
3. Turbine Operation:
• The high-pressure steam enters the turbine at high velocity, causing the turbine blades to
rotate.
• As the steam expands and loses pressure, its energy is converted into rotational
mechanical energy in the turbine.
4. Generator Operation:
• The rotating turbine shaft is connected to the generator rotor.
• The mechanical energy from the turbine is transferred to the generator rotor, causing it to
rotate within a magnetic field.
5. Electricity Generation:
• The rotation of the generator rotor induces an electric current in the generator windings,
according to Faraday's law of electromagnetic induction.
• This alternating current (AC) is then converted into a high-voltage alternating current for
transmission through transformers.
6. Condensation:
• After passing through the turbine, the low-pressure steam exits into the condenser.
• In the condenser, the steam is condensed back into water by cooling it with cold water
from a cooling tower or a nearby water source.
7. Water Recycling:
• The condensed water, known as condensate, is pumped back to the boiler feedwater
heater.
 • Some of the condensate is preheated before returning to the boiler, reducing the amount
of fuel needed to heat it back to steam.
8. Heat Rejection:
• The heat absorbed from the steam in the condenser is transferred to the cooling water.
• The heated cooling water is then discharged from the plant, either back into a natural
water body or through a cooling tower.
Example:
Coal-fired power plant, where coal is burned in a boiler to produce steam, which drives a turbine connected
to a generator.
Applications:
• Large-scale electricity generation for utility grids.
• Industrial processes requiring significant power.
• Heating applications in district heating systems.
Advantages:
• Well-established technology with high efficiency.
• Can utilize a variety of fuel sources, including coal, natural gas, and nuclear.
• Provides stable and reliable electricity generation.
Disadvantages:
• Environmental impact due to emissions of greenhouse gases and pollutants.
• Water consumption for steam generation and cooling.

Working principle of Diesel power plants

2. Draw a neat sketch of a Diesel engine power plant showing all the important
components and discuss their function.
Answer:
Diesel Power Plant:
• A diesel power plant is a facility that generates electricity using diesel engines as prime movers to
convert the chemical energy of diesel fuel into mechanical energy, which is then converted into
electrical energy.
• In a diesel power plant, diesel fuel is injected into the combustion chamber of the diesel
engine, where it ignites due to compression. The burning fuel-air mixture expands
rapidly, driving the piston down and generating mechanical energy. This mechanical
energy is then used to rotate the generator shaft, which produces electricity.
Parts:
1. Diesel Engine: Converts the chemical energy of diesel fuel into mechanical energy through
combustion.
 2. Generator: Converts mechanical energy from the diesel engine into electrical energy.
3. Fuel System: Stores, filters, and delivers diesel fuel to the engine.
4. Cooling System: Maintains the engine temperature within optimal limits to ensure efficient
operation.
5. Lubrication System: Provides lubrication to engine components to reduce friction and wear.

Working:
• Diesel fuel is injected into the combustion chamber of the diesel engine.
• Fuel-air mixture ignites due to compression and burns rapidly, generating high-pressure gases.
• The expanding gases drive the piston down, rotating the crankshaft connected to the generator.
• The rotating generator produces electricity, which is then distributed to consumers through the
electrical grid.
Steps Involved:
1. Fuel injection
2. Combustion
3. Piston movement
4. Crankshaft rotation
5. Generator operation
6. Electricity generation
1. Fuel Injection:
• Diesel fuel is injected into the combustion chamber of the diesel engine.
• The fuel is atomized into a fine mist and mixed with air for combustion.
2. Combustion:
 • The injected diesel fuel ignites spontaneously due to the high temperature and pressure created
by the compression of air in the combustion chamber.
• The combustion process releases energy in the form of heat.
3. Piston Movement:
• Rapid expansion of high-pressure gases resulting from combustion forces the piston downward
in the cylinder. This downward movement of the piston is converted into linear motion.
4. Crankshaft Rotation:
• The linear motion of the piston is converted into rotational motion by the crankshaft.
• The crankshaft is connected to the piston via a connecting rod, and as the piston moves, it turns
the crankshaft.
5. Generator Operation:
• Rotational motion of the crankshaft is transmitted to the generator shaft through a system of
gears/belts.
• The generator shaft, also known as the rotor, spins within a stationary magnetic field, inducing
an electric current in the generator windings.
6. Electricity Generation:
• Induced electric current flows through generator windings & collected at the generator
terminals.
• This alternating current (AC) is then converted into a suitable voltage and frequency for
distribution to consumers.
Example: A standby generator used in commercial buildings or emergency backup systems.
Applications:
• Backup or standby power generation for critical facilities such as hospitals, data centers, and
telecommunications towers.
• Prime power generation in remote locations or areas without access to the electrical grid.
Advantages:
• Quick start-up time, making them suitable for emergency power applications.
• High efficiency and reliability. Availability of fuel in various locations.
Disadvantages:
• Dependence on diesel fuel, which can be expensive and subject to price fluctuations.
• Environmental concerns due to emissions of pollutants such as nitrogen oxides & particulate
matter. Maintenance requirements for diesel engines can be costly.

Working principle of Hydropower plants

3. Draw the typical layout and explain the workings of a hydroelectric power plant. (or)
Explain with a simple sketch, the working of a hydroelectric power plant.
Answer:
Hydro Power Plant:
 • A hydro power plant is a facility that generates electricity by utilizing the potential energy of
flowing water to drive turbines connected to generators, converting mechanical energy into
electrical energy.
▪ In a hydro power plant, the potential energy of stored water in a reservoir is
converted into kinetic energy as it flows through the penstock and drives the
turbines. The rotating turbines turn generators, producing electricity.

Parts:
1. Dam: A structure built across a river to create a reservoir and regulate the flow of water.
2. Intake: Opening through which water from the reservoir enters the penstock.
3. Penstock: Large pipes or channels that convey water from the reservoir to the turbines.
4. Turbines: Machines that convert the kinetic energy of flowing water into mechanical energy.
5. Generators: Devices that convert mechanical energy from the turbines into electrical energy.
6. Powerhouse: Building housing the turbines, generators, and other electrical equipment.
7. Tailrace: Channel or pipe through which water exits the powerhouse and returns to the river.
Working:
• Water stored in a reservoir behind a dam is released through the intake and flows down the
penstock.
• The flowing water drives the turbines, causing them to rotate.
• The rotating turbines are connected to generators, which produce electricity through
electromagnetic induction.
• The generated electricity is transmitted to consumers through power lines.
Steps Involved:
1. Water intake from reservoir
2. Flow through penstock
3. Turbine rotation
4. Generator operation
5. Electricity generation
6. Release of water through tailrace
1. Water Intake:
• The water from the reservoir behind the dam is directed into the intake structure.
• Intake gates control the flow of water into the penstock.
2. Flow through Penstock:
• The water flows under gravity through the penstock, a large pipe or channel.
• The penstock channels the water from the reservoir to the turbines.
3. Turbine Rotation:
• The high-pressure water from the penstock enters the turbine blades.
• The force of the flowing water causes the turbine blades to rotate.
4. Generator Operation:
• The rotating turbine shaft is connected to the rotor of the generator.
• The mechanical energy from the turbine is converted into electrical energy in the generator.
5. Electricity Generation:
• The generator produces electricity as the rotor spins within a stationary magnetic field.
• The electricity generated is transmitted through electrical cables or transmission lines.
6. Release of Water through Tailrace:
• After passing through the turbines, the water exits the powerhouse through the tailrace.
• The tailrace channels the water back into the river downstream of the dam.
Example: Hoover Dam in the United States is a notable example of a hydro power plant.
Applications:
• Large-scale electricity generation for utility grids.
• Energy supply for industrial processes.
• Irrigation and agricultural applications.
Advantages:
• Renewable energy source with minimal greenhouse gas emissions.
• Provides a reliable and consistent source of electricity.
• Offers flexibility in operation and can quickly adjust to changes in demand.
Disadvantages:
 • High initial capital costs for construction.
• Environmental impact on ecosystems and aquatic habitats.
• Reliance on specific geographical locations with suitable water resources.

Working principle of Nuclear power plants

4. Enumerate and explain the essential components of a nuclear reactor

Answer:
Nuclear Power Plant:
• A nuclear power plant is a facility that generates electricity through controlled nuclear fission
reactions, where the energy released from splitting atomic nuclei is used to heat water and produce
steam to drive turbines connected to generators.
• In a nuclear power plant, nuclear fission reactions are initiated and controlled within the
reactor core, releasing a large amount of heat. This heat is used to produce steam, which
drives turbines connected to generators, ultimately producing electricity.
Parts:
1. Reactor Core: Contains nuclear fuel rods where fission reactions occur.
2. Control Rods: Inserted into the reactor core to control the rate of fission reactions..
3. Coolant System: Circulates water/liquid metal coolant to shift heat away from the reactor core.
4. Steam Generator: Converts the heat from the reactor coolant into steam.
5. Turbine: Converts the pressure energy of steam into mechanical energy.
6. Generator: Converts mechanical energy from the turbine into electrical energy.
Working:
• Nuclear fuel rods, typically containing uranium or plutonium, undergo controlled fission
reactions, releasing heat energy.
• The heat generated heats the coolant circulating through the reactor core.
• The hot coolant transfers its heat to a separate water loop in the steam generator,
converting it into steam.
• The high-pressure steam drives turbines, causing them to rotate. The
rotating turbines are connected to generators, producing electricity
through electromagnetic induction.
• The electricity generated is then transmitted to consumers through the electrical grid.
Steps Involved:
1. Initiation of controlled nuclear fission reactions.
2. Heat generation within the reactor core.
3. Heat transfer to the coolant circulating through the core.
4. Conversion of coolant heat into steam in the steam generator.
5. Turbine rotation due to high-pressure steam.
 6. Electricity generation in the generator.
7. Transmission of electricity to consumers.
1. Initiation of Controlled Nuclear Fission Reactions:
• Neutrons are introduced into the reactor core to initiate fission reactions.
• Control rods are adjusted to regulate the rate of fission reactions and maintain a steady power
output.
2. Heat Generation within the Reactor Core:
• Nuclear fission reactions occur within the reactor core, releasing a large amount of heat energy.
• Fuel rods containing uranium or plutonium undergo fission, splitting into smaller nuclei and
releasing energy in the form of heat and radiation.

3. Heat Transfer to the Coolant:

 • The heat generated in the reactor core is transferred to the coolant circulating through the core.
• The coolant, typically water or liquid metal, absorbs the heat energy from the fuel rods.
4. Conversion of Coolant Heat into Steam:
• The hot coolant transfers its heat to a separate water loop in the steam generator.
• The heat from the coolant boils the water, producing steam at high pressure.
5. Turbine Rotation due to High-Pressure Steam:
• The high-pressure steam produced in the steam generator is directed to the turbine.
• The force of the steam flow causes the turbine blades to rotate.
6. Electricity Generation in the Generator:
• The rotating turbine shaft is connected to the rotor of the generator.
• The mechanical energy from the turbine rotation is converted into electrical energy in the generator.
7. Transmission of Electricity to Consumers:
• The electricity generated in the generator is transmitted to consumers through the electrical grid.
• Transformers adjust the voltage of the electricity for efficient transmission and distribution.
Example:
• Chernobyl Nuclear Power Plant in Ukraine and Three Mile Island Nuclear Generating Station in the
United States are notable examples of nuclear power plants.
Applications:
• Large-scale electricity generation for utility grids.
• Powering of naval vessels, such as submarines and aircraft carriers.
Advantages:
• High energy density of nuclear fuel results in large amounts of electricity generation.
• Relatively low greenhouse gas emissions compared to fossil fuel power plants.
• Stable and reliable source of electricity with continuous operation.
Disadvantages:
• Potential risks associated with nuclear accidents and radioactive contamination.
• High initial construction costs and long lead times for building new plants.
• Concerns about nuclear waste disposal and proliferation of nuclear materials.

UNIT-VI, Part-B
Mechanical Power Transmission
Belt Drives, Chain, Rope drives , Gears
Short answer questions.
1) Name various types of belts used for the transmission of power.
Ans: Flat belt, V belt and circular belt.
2) Enlist various belt drives. Name any three belt materials.
Ans: Open belt drive and crossed belt drive. Rubber, Leather , balata are the materials used for belts.
3) Explain the phenomena of ‘slip’ in a belt drive.
• Ans: Sometimes, the frictional grip becomes insufficient between the belt and pulley. This may cause
some forward motion of the driver without carrying the belt with it. This may also cause some
 forward motion of the belt without carrying the driven pulley with it. This is called slip of the belt and
is generally expressed as a percentage. The result of the belt slipping is to reduce the velocity ratio of
the system.
4) Differentiate between a belt drive and a chain drive.
Ans: In Belt drive slip occurs and in chain drives slip will not occur.
5) Distinguish open and crossed belt drive.
Ans: In open belt drive belt simply surrounds on the pulleys, whereas in crossed belt drive belt in crossed belt
drive, belt proceeds from the top of one pulley to the bottom of other pulley and thus crosses itself in
between two pulleys.
6) What is the advantage of Chain drive over belt drive .
Ans: In Belt drive slip occurs and in chain drives slip will not occur.
7) Distinguish fabric rope and wire rope.
Ans: In fabric rope is rope is made with hemp or manila, whereas wire rope is made with metal wire.
8) Write the applications of wire rope drives.
Ans: 1.These are lighter in weight, 2. These offer silent operation,
3. These can withstand shock loads, 4.These are more reliable,
5.They do not fail suddenly, 6. These are more durable,
9) What are the materials used for belt drives?
Ans: Rubber, Leather, cotton or fabric and balata .
10) Compare belt and chain drives.
Ans: In Belt drive slip occurs and in chain drives slip will not occur.
11. How the gears are classified?
Ans: Spur gears, helical gears, bevel gears, worm and worm wheel , rack and pinion
12. What is the application of rack and pinion ?
Ans: It converts rotary motion into reciprocating motion.
13. List the gear drive applications.
Ans: Gear drives are applied for power transmission with high efficiency. Applications are
Automotive transmission systems, Marine equipment, Turbines and various Engines.

Descriptive Questions
1. Explain the types of Belt and Rope Drives with neat sketches.
Types of Belts based on Cross section.
1. Flat Belt
2. V-Belt
3. Circular Belt or Rope
1. Flat belt. The flat belt, as shown in Fig.1 (a), is mostly used in the factories and
workshops, where a moderate amount of power is to be transmitted, from one pulley to another
when the two pulleys are not more than 8 meters apart.
Advantages of flat belt
▪ Used for high-speed transmission
▪ Absorbs shock and vibration
 ▪ Used for industrial purposes
▪ Longer life when properly maintained
▪ Used for very high-speed ratio
▪ Will not come out of grove
▪ More drives can be taken from a single pulley
2. V-belt. The V-belt, as shown in Fig.1 (b), is mostly used in factories and workshops,
where a moderate amount of power is to be transmitted, from one pulley to another, when the two
pulleys are very near to each other.
3. Circular belt or rope. Circular belt or rope, as shown in Fig.1 (c), is mostly used in the
factories, where a great amount of power is to be transmitted, from one pulley to another, when
the two pulleys are more than 8meters apart.

V Belt

The rope drives use the following two types of ropes:

1. Fiber Ropes
2. Wire Ropes.
• The Fiber ropes operate successfully when the pulleys are about 60 meters apart,
• The Wire ropes are used when the pulleys are up to 150 meters apart.
1. Fiber Ropes
The ropes for transmitting power are usually made from fibrous materials such as hemp, manila and
cotton. Since the hemp and manila fibres are rough, therefore the ropes made from these fibres are not very
flexible and possesses poor mechanical properties. The hemp ropes have less strength as compared to
manila ropes. When the hemp and manila ropes are bent over the pulley, there is some sliding of fibres,
causing the rope to wear and chafe internally. In order to minimize this defect, the rope fibres are lubricated
with a tar or graphite. The lubrication also makes the rope moisture proof. Hemp ropes are suitable only for
hand operated hoisting machinery and as tie ropes for lifting tackle, hooks etc.
Advantages of Fiber Rope Drives
i. They give smooth, steady and quiet service.
ii. They are little affected by outdoor conditions.
iii. The shafts may be out of strict alignment.
iv. They give high mechanical efficiency
2. Wire Ropes:
When a large amount of power is to be transmitted over long distances from one pulley to another (i.e., when
the pulleys are up to 150 meters apart), then wire ropes are used. Wire ropes are widely used in elevators,
mine hoists, cranes, conveyors, hauling devices and suspension bridges. The wire ropes run on grooved
pulleys, but they rest on the bottom of the grooves and are not wedged between the sides of the grooves.

2. Compare belt, chain & Gear drive for transmission of power.

Feature Belt Drive Chain Drive Gear Drive
Main Element Flexible belt, Pulleys Roller chain, sprockets Interlocking gears
Slip Moderate Low (positive drive) Negligible(positive sdive)
Suitability Light to moderate loads, Moderate to heavy loads, for Heavy loads, for short center
for large center distance moderate center distance distance
Space Requires moderate space Requires moderate space Requires minimal space
Requirement
Design Flexible, adaptable Rigid, fixed Rigid, fixed
Manufacturing Low Moderate High
Complexity
Failure Belt wear, stretching Chain stretch, link wear Gear tooth wear, misalignment
Life Moderate, affected by Long, with proper Long, with proper maintenance
belt wear maintenance
Lubrication Usually not required Regular lubrication needed Generally not required
Installation Cost Low Moderate High
Use Light-duty, low velocity Medium to heavy-duty, Heavy-duty, high velocity
applications moderate velocity application applications

3. What is open and crossed belt drive ? Compare them.

Types of Belts based on Arrangement:
1. Open Belt Drive
2. Crossed Belt Drive
1. Open belt drive:
• In open belt drive arrangement, belt proceeds from top of one pulley to the top of other
pulley without crossing. So, the driver shaft and driven shaft rotate in the same direction.
The open belt drive, as shown in Fig.2, is used with shafts arranged parallel and rotating in
the same direction. In this case, the driver A pulls the belt from one side (i.e., lower side
RQ) and delivers it to the other side (i.e., upper side LM). Thus, the tension in the lower
 side belt will be more than that in the upper side belt. The lower side belt (because of more
tension) is known as tight side whereas the upper side belt (because of less tension) is
known as slack side, as shown in Fig.

2. Crossed Belt Drive:

• In crossed belt drive, belt proceeds from the top of one pulley to the bottom of other pulley
and thus crosses itself in between two pulleys. Here the driving shaft and driven shaft
rotate in opposite directions. It offers higher contact angles, so power or torque
transmission capacity also increases. However, due to crossing, the belt continuously rubs
itself, which leads to a reduction in the life of belt.
Differences between Open belt drive and Crosse belt drive
Open Belt Drive Crossed Belt Drive
In open belt drive, belt proceeds from top of one In crossed belt drive, belt proceeds from top of one
pulley to the top of other pulley without crossing. pulley to the bottom of another pulley and thus
crosses itself.
In open belt drive, driving shaft and driven shaft In cross belt drive, driving shaft and driven shaft
rotate in same direction. rotate in opposite direction.

Contact angle (or wrap angle) between the belt and Contact angle between the belt and pulley is
pulley is comparatively small (always below 180º). comparatively large (always above 180º).

Length of the open belt is smaller as compared to For the same pulley diameter and same center
cross belt. distance between driver and driven shaft, longer belt
is required in cross belt drive.
Here the belt does not rub by itself. So, belt life Here belt rubs with itself and thus life of the belt
increases. reduces.
Open belt drive is suitable when driving and driven Cross belt drive can be advantageously applied for
shafts are in horizontal or little bit inclined. horizontal, inclined and vertical positions of driving
and driven shafts.
Power transmission capacity is small due to smaller It can transmit more power as wrap angle is more.
wrap angle.

4. Discuss in detail chain drive types. State advantages and disadvantages.

CHAIN DRIVE:
• The chain drive consists of three elements – driving sprocket, driven sprocket, and endless chain
wrapped around the sprocket as shown in fig. Pin joint contains, pin, bush, and roller to minimize
the friction and such chains are known as roller bush chains.
• The chain drive is a positive drive where there is no slip & a constant velocity ratio can be
maintained. Chain drive used in bicycle, motorbike, printing machine, textile machine, etc.
• An endless chain running over toothed wheels mounted on the driver and driven shafts. The smaller
wheel is called pinion and the other is called wheel.
• The chain consists of plates, pins and bushes made of high-grade steel. There are hoisting chains
and pulling chains apart from the power transmitting chains. Roller chains and silent/inverted chains
are the different types of power transmitting chains.
Classification of Chains
The chains, on the basis of their use, are classified into the following three groups:
1. Hoisting and hauling (or crane) Chains,
2. Conveyor (or tractive) Chains, and
3. Power transmitting (or driving) Chains.
1. Hoisting and Hauling (or crane) Chains
• These chains are used for hoisting (lifting) and hauling (moving) purposes. The hoisting and
hauling chains are of the following two types:
a. Chain with oval links
b. Chain with square links

a. Chain with oval links: The links of this type of chain are of oval shape, as shown in Fig. (a).
The joint of each link is welded. Such type of chains is used only at low speeds such as in chain
hoists and in anchors for marine works.
b. Chain with square links: Links of this type of chain are of square shape, as shown in Fig. (b).
Such type of chains is used in hoists, cranes, dredges. The manufacturing cost of this typeof chain is
less than that of chain with oval links
2. Conveyor (or tractive) Chains
• These chains are used for elevating and conveying the materials Continuously. The conveyor
chains are of the following two types:
a. Detachable or hook joint type chain
b. Closed joint type chain.

• The conveyor chains are usually made of malleable cast iron. These chains do not have
smooth running qualities. The conveyor chains run at slow speeds of about 3 to 12 km.p.h.
3. Power Transmitting (or driving) Chains.
• Power transmitting (or driving) chains are mechanisms used to transfer mechanical power from one
 component to another within a machine or system. They consist of a series of interconnected links
that transmit motion and force between input and output components.

Advantages of Chain drive.

➢ Positive drive as there is no slip, hence a constant velocity ratio.
➢ Occupies less space compared to belt drive.
➢ Life is more compared to the belt drive.
➢ Used for large center distance.
➢ Transmission efficiency is larger than the belt drive.
Disadvantages of Chain Drive:
o Noisy compared to belt drive.
o Initial cost is higher compared to belt drive.
o Initial cost is higher compared to belt drive.
o Adjustment in the center distance is necessary.
o Maintenance cost is higher & complex compared to belt drive

5. What are the various types of gears used and give their applications. .
Ans:
GEAR DRIVE:
A gear is a rotating machine part having cut teeth, which mesh with another toothed part in order to
transmit torque and power. In order to transmit a definite power from one shaft to another shaft to the
projection on one disc and recesses on another disc can be made which can mesh with each other. In the
early days, friction discs were used for transmitting the power from one shaft to another shaft. In such a
case, the power transmission capacity depends on the friction between surfaces of two discs. Therefore,
this method is not suitable for transmitting higher power as a slip occurs between the discs.
 Types of Gear Drives:
i. Spur gear,
ii. Helical gear,
iii. Rack and Pinion,
iv. Bevel gear,
v. Worm and worm wheel.

i. Spur Gears:
• Spur gears have teeth that are parallel to the axis of rotation. They are the most common
type of gear and are often used for speed reduction or increase.
• They can produce noise and vibration due to the sudden engagement of teeth.
• Applications: Gearboxes, Industrial Machinery, and Automotive Transmissions, Electric
screwdrivers, hand-cranked mechanisms, simple gearboxes in toys.

ii. Helical Gears:

• Helical gears have teeth that are inclined at an angle to the axis of rotation. This helix
angle causes smoother and quieter operation compared to spur gears.
 • Helical gears transmit motion and power more smoothly due to the gradual engagement of
teeth. They can handle higher loads and speeds than spur gears.
• Applications: Helical gears are commonly found in automotive transmissions, machine
tools, and gear pumps, Power drills, printing presses, conveyor systems in manufacturing.

iii. Bevel Gears:

• Bevel gears have cone-shaped teeth and are used to transmit motion between intersecting
shafts. They can have straight, spiral, or hypoid tooth designs.
• Bevel gears are used to change the direction of motion (usually 90º) between shafts.
• Applications: Bevel gears are used in differential mechanisms, marine propulsion systems,
and power tools, Hand drills, hand-cranked winches, bicycle gear systems.

iv. Worm Gears:

• Worm gears consist of a worm (a screw-like gear) and a mating gear called a worm wheel.
They transmit motion at right angles and are used for large speed reductions.
• Worm gears provide high gear ratios and are self-locking, meaning they can hold position
without a brake. However, they can have lower efficiency due to friction.
• Applications: Worm gears are commonly used in conveyor systems, lifting mechanisms,
and automotive steering systems, Hand-operated winches, rolling gates, hobbyist robotics.
 v. Rack and Pinion:
• A rack and pinion consist of a linear gear (rack) and a cylindrical gear (pinion). They
convert rotational motion into linear motion or vice versa.
• Rack and pinion systems are commonly used for linear motion applications such as steering
mechanisms, CNC machines, and elevators. Offer precise control and high efficiency.
• Applications: Rack and pinion gears are found in automotive steering systems, machine
tools, and industrial automation, Electric screw jacks, toy cars with multiple speeds, hand-
operated egg beaters.

Advantages of Gear Drive:

• Positive drive and has more efficiency than belt and rope drive.
• The operation of the drive is simple and effective.
• Life is more compared to other drives.
• With one input speed, no. of output speeds can be obtained by using a suitable gear drive.
• Constant velocity ration is obtained.
Disadvantages of Gear Drive:
• If the tooth geometry of the gear is not properly maintained, the drive may get locked.
• Not preferred when very high-speed transmission is required.
• If the lubrication arrangement is not provided, it may produce noise.

UNIT-VI, Part-C
Introduction to Robotics - Joints & links, configurations, and applications of robotics Short
answer questions
1) What is Robotics ?
Ans: "Robotics" is defined as the science of designing and building Robots which are suitable for real life application in
automated manufacturing and other non-manufacturing environments. It has the following objectives,
2) Explain the laws of Robotics.
Ans: Asimov's laws of robotics
The Three Laws of Robotics or Asimov's Laws are a set of rules devised by the science fiction author IsaacAsimov
• First Law - A robot may not injure a human being or, through inaction, allow a human being to come to harm.
• Second Law - A robot must obey the orders given to it by human beings except where such orders would
conflictwith the First Law.
• Third Law - A robot must protect its own existence as long as such protection does not conflict with the First or
 Second Laws.
3) What are the future applications of Robot?
Ans: Intelligence, Sensor capabilities, Telepresence, Mechanical design,
Mobility and navigation (walking machines), Universal gripper,Systems and integration and
networking, Flexible Manufacturing Systems (FMS), Hazardous and inaccessible non-
manufacturing environments, Underground coal mining, Firefighting operations.
4) How do you classify robots by coordinate system?
Ans: Polar configuration, Cylindrical configuration, Cartesian coordinate configuration and
Jointed-arm configurations.
5) Define a robot and give its applications.
Ans: A robot is an autonomous machine capable of sensing its environment, carrying out computations to
make decisions, and performing actions in the real world. Robot is a machine resembling a human being
and able to replicate certain human movements and functions automatically.
Applications of Robots :
• Material transfer applications : Machine loading and unloading.
• Processing operations : Spot welding, Continuous arc welding, Spray coating
• Machining operations : Drilling, Grinding, Polishing, and cutting etc.,
• Assembly tasks : Assembly cell designs, parts mating, Inspection, automation.
6) What are the basic components of a robotic system?
Ans: Sensors, end effector, controller, robotic arm
7) What are the various types of joints used in robots?
– Ans: Prismatic Joints - Used for Linear Motions
Revolute Joints - Used for Rotational Motions
8) List the various degrees of freedom in robot configuration.
Ans: Total 6 Degrees of freedom. 3 Linear/ Translation motions and 3 Rotational motions.
9) Write a note on movement of Robots.
Ans: There are three primary types of moves that a robot system uses to navigate around the
physical world: linear, joint, and circular moves. While the goal of all those moves is the same—
moving from point A to point B—the path that the robot takes along the way is the major determining
factor for each move type.
10) Briefly explain the need for robots in industries.
Ans: Typical applications of robots include welding, painting, assembly, disassembly, pick and place for
printed circuit boards, packaging and labeling, palletizing, product inspection, and testing; all
accomplished with high endurance, speed, and precision. They can assist in material handling.
Descriptive questions
1) Name and discuss the four basic arm configurations that are used in robotic manipulators.
OR
2 List the types of robot configurations? Explain any one with neat sketch.
Ans:

Classification by Configuration & Co-ordinate System

• Industrial robots are available in a wide variety of sizes, shapes, and physical configurations. The
vast majorityof today’s commercially available robots possess one of the basic configurations:
i. Cartesian Coordinate Configuration [3P]
ii. Cylindrical Configuration [2P1R]
iii. Polar Configuration: Spherical Coordinate [1P2R]
iv. Articulate Configuration: Jointed-Arm Configuration [1P3R]

i. Cartesian Coordinate Configuration: [3P]

• Made with 3 Prismatic Joints

• The cartesian coordinate robot, illustrated in Fig, uses three perpendicular slides to construct the x, y,
and z axes. Other names are sometimes applied with this configuration, including xyz robot and
rectilinear robot, by moving the three slides relative to one another, the robot is capable of
 operating within a rectangular work envelope.
ii. Cylindrical Configuration: [2P1R]

• Made with 2 Prismatic Joint & 1 Revolving Joints

• The cylindrical configurable, as shown in fig, uses a vertical column and a slide that can be moved
up or down along the column. The robot arm is attached to the slide so that it can be moved radially
with respect to the column. By routing the column, the robot is capable of achieving a workspace that
approximates a cylinder.
iii. Polar Configuration: Spherical Coordinate: [1P2R]

• Made with 1Prismatic & 2 Revolving Joints

• The polar configuration is pictured in Fig. It uses a telescoping arm that can be raised or lowered
about a horizontal pivot The pivot is mounted on a base These various joints provide the robot with
the capability to move its arm within a spherical space, and hence the name “spherical coordinate”
robot is sometimes applied to this type. A number of commercial robots possess polar configuration.
iv. Articulate Configuration: Jointed-Arm Configuration: [1P3R]

• Made with 1 Prismatic & 3 Revolving Joints

 • The joint-arm robot is pictured in Fig. Its configuration is similar to that of the human arm. It
consists of two straight components. Corresponding to the human forearm and upper arm, mounted
on a vertical pedestal. These components are connected by two rotary joints corresponding to the
shoulder and elbow.
Scope and Limitations of Robots:
The advanced version of machines are robots which are used to do advanced tasks and are programmed to
make decisions on their own. When a robot is designed the most important thing to be kept in mind is what
the function is to be performed and what are the limitations of the robot. Each robot has a basic level of
complexity and each of the levels has the scope which limits the functions that are to be performed. For
general basic robots, their complexity is decided by the number of limbs, actuators and the sensors that are
used while for advanced robots the complexity is decided by the number of microprocessors and
microcontroller used. As any component in the robot, it is increasing the scope of the robot and with every
joint added, the degree of the robot is enhanced.
Advantages:
• They can get information that a human can’t get.
• They can perform tasks without any mistakes and very efficiently and fast.
• Maximum robots are automatic, so they can perform different tasks without needing human
interaction.
• Robots are used in different factories to produce items like plane, car parts etc.
• They can be used for mining purposes and explosive zones.
Disadvantages:
• They need the power supply to keep going. People working in factories may lose their jobs
as robots can replace them.
• They need high maintenance to keep them working all day long. And the cost of maintaining
the robots can be expensive.
• They can store huge amount of data, but they are not as efficient as our human brains.
• As we know that robots work on the program that has been installed in them. So other than
the program installed, robots can’t do anything different.
• The most important disadvantage is that if the program of robots comes in wrong hands,
they can cause the huge amount of destruction.
Applications of Robots: -
• Material transfer applications
• Machine loading and unloading.
• Processing operations like, Spot welding, Continuous arc welding, Spray coating,
Drilling, machining operations, Grinding, polishing, Laser drilling and cutting etc.
• Assembly tasks, assembly cell designs, parts mating.
 • Inspection, automation.
3.Enlist the applications and characteristics of future robots.
Ans: Future Applications of Robots
The profile of the future robot based on the research activities will include the following,
1. Intelligence, Sensor capabilities, Telepresence, Mechanical design,
2. Mobility and navigation (walking machines)
3. Universal gripper
4. Systems and integration and networking
5. Flexible Manufacturing Systems (FMS)
6. Hazardous and inaccessible non-manufacturing environments
7. Underground coal mining
8. Firefighting operations
9. Robots in space
10. Security guards
11. Garbage collection and waste disposal operations
12. Household robots
13. Medical care and hospital duties etc.
 4.Sketch a robot and name its parts.

5. Explain the use of robots in medical applications.

• Advancements in robotics could enable robots to perform..
▪ Lab tests without human intervention,
▪ Remove plaque from arteries, take tissue biopsies, and attack cancerous tumors.
▪ Deliver targeted medication, provide patient care for minor issues, and speak to
patients about their symptoms.
• Surgical Robotics:
▪ Minimally Invasive Surgery (MIS): Surgical robots, such as the da
Vinci Surgical System, enable surgeons to perform complex procedures
through small incisions with enhanced dexterity and visualization.
 ▪ Orthopedic Surgery: Robots assist in tasks like bone cutting, joint
replacement surgeries, and spinal procedures, improving accuracy
▪ Neurosurgery: Robotic systems aid in delicate procedures, such as
tumor removal and deep brain stimulation, by precise navigation within
brain.
▪ Robot-Assisted Catheterization: Robots assist cardiologists and
vascular surgeons in navigating catheters through blood vessels.
• Rehabilitation Robotics:
▪ Exoskeletons: These robotic devices help patients regain mobility and
strength after stroke, spinal cord injury, or other neurological
conditions.
▪ Robotic Prosthetics: Advanced prosthetic limbs with robotic
components mimic natural movements more closely.
• Telemedicine and Remote Surgery:
▪ Perform procedures remotely, reaching patients in remote or
underserved areas & providing expert care with no physical presence.
▪ Telepresence robots equipped with cameras and screens allow physicians
to conduct virtual consultations and examinations.
• Drug Delivery and Therapy:
▪ Robotic Pill Deliver: Swallowable robotic capsules can deliver
medications to specific locations within the gastrointestinal tract,
enabling targeted drug delivery and reducing side effects.
• Robotic-Assisted Therapy: Physical & occupational therapy by guiding patients
through exercises, providing feedback
• Diagnostic and Imaging:
▪ Robot-Assisted Imagin: Positioning patients in imaging procedures
such as MRI, CT scans & ultrasound, giving accurate and consistent
image.
• Laboratory Automation:
▪ Tasks in laboratories, such as sample preparation, pipetting, and
specimen handling, increasing efficiency, reducing human error, and
accelerating the pace of research and diagnostics.
 6) Justify the statement: Actuators are the muscles of robots.
Ans: An actuator is a part of a device or machine that helps it to achieve physical movements by converting
energy, often electrical, air, or hydraulic, into mechanical force. Simply put, it is the component in any
machine that enables movement. Like muscles in a body that enable energy to be converted to some form
of motion like the movement of arms or legs, actuators work in a machine to perform a mechanical action.
Common examples of actuators include electric motors, stepper motors, jackscrews, electric muscular
stimulators in robots, etc.
• They are the components that enable robots to interact with their environment by converting energy
into motion. This conversion process is what allows robots to perform tasks ranging from simple to
complex. Actuators are the driving force behind a robot's ability to move.
Some types of Actuators:
1. Electrical Actuators
2. Pneumatic actuators
3. Hydraulic Actuators
4. Piezoelectric Actuators
1. Electric motors: Electric motors are the most common type of actuator used in robotics. They work
by converting electrical energy into mechanical energy, which is used to rotate a shaft or other
component. There are several types of electric motors that can be used in robotics, including brushed
DC motors, brushless DC motors, and stepper motors.
2. Pneumatic Actuators: Pneumatic actuators use compressed air to generate motion. They consist of
a cylinder with a piston inside, which is moved by the pressure of the compressed air. Pneumatic
actuators are commonly used in robotics because they are relatively simple and inexpensive, and they
can generate a large amount of force.
3. Hydraulic Actuators: Hydraulic actuators use pressurized fluid to generate motion. They consist of
a cylinder with a piston inside, which is moved by the pressure of the fluid. Hydraulic actuators are
commonly used in robotics because they can generate a very large amount of force, but they can be
more complex and expensive than other types of actuators.
4. Piezoelectric Actuators: Piezoelectric actuators use the piezoelectric effect to generate motion.
They consist of a crystal that expands or contracts when an electrical voltage is applied to it.
Piezoelectric actuators are commonly used in robotics because they are small, lightweight, and can
generate very precise movements.