Module 4

ENGINEERING MATERIALS

Ferrous and Non-Ferrous Metals

Category Type Composition Properties Applications

Iron, Carbon (0.05%– High tensile strength, Construction,
Ferrous Carbon
2%), Manganese, Silicon, ductile (low carbon), pipelines, automotive
Metals Steel
Sulfur brittle (high carbon) bodies
 Category Type Composition Properties Applications
Iron, Chromium (10.5%– Corrosion-resistant, Kitchenware, medical
Stainless
30%), Nickel, durable, high tensile instruments, aerospace
Steel
Molybdenum, Carbon strength components
Iron, Carbon (2%–4%), Wear-resistant, brittle, Engine blocks, pipes,
Cast Iron
Silicon (1%–3%) good machinability machinery bases
High hardness,
Iron, Carbon, Tungsten,
resistance to Cutting tools, dies,
Tool Steel Molybdenum,
deformation under molds
Chromium, Vanadium
stress
Wrought Nearly pure iron, very Malleable, corrosion- Decorative gates,
Iron low carbon resistant, easy to weld railings, chains
Pure aluminum or alloys Lightweight, corrosion- Aircraft bodies,
Aluminum with copper, manganese, resistant, good packaging, automotive
silicon conductivity parts
Pure copper or alloys Excellent electrical and Electrical wiring,
Copper like bronze (copper-tin), thermal conductivity, plumbing, heat
brass (copper-zinc) ductile exchangers
Corrosion-resistant, Galvanizing steel,
Zinc Pure zinc or zinc alloys
malleable batteries, die-casting
Lead with minor
Heavy, soft, corrosion- Batteries, radiation
Lead antimony or other
resistant shielding, roofing
elements
Non- Coating for steel,
Ferrous Pure tin or alloys like Corrosion-resistant,
Tin soldering, food
Metals solder (tin-lead) soft, malleable
preservation
Coinage, batteries,
Pure nickel or nickel Hard, corrosion-
Nickel superalloys for
alloys resistant, magnetic
turbines
Aerospace
High strength-to-weight
Titanium with components, medical
Titanium ratio, corrosion-
aluminum, vanadium implants, sports
resistant
equipment
Magnesium with Automotive parts,
Lightweight, strong,
Magnesium aluminum, zinc, lightweight structural
machinable
manganese materials

POLYMERS:

Polymers are large molecules composed of repeating structural units called monomers, which are
bonded together through chemical processes. They can be natural or synthetic, with a wide range of
properties and applications.

Types of Polymers
1. Natural Polymers: Found in nature and include materials like proteins, cellulose, and rubber.
2. Synthetic Polymers: Man-made polymers created through chemical processes, such as
plastics, nylon, and silicone.

Properties of Polymers
1. Lightweight
2. Durability
3. Flexibility
Applications
1. Construction: Pipes, insulation materials.
2. Electronics: Insulators, circuit boards.
3. Medical: Sutures, implants, drug delivery systems.
4. Automotive: Tires, dashboards, lightweight body panels.
5. Consumer Goods: Packaging, textiles, toys.

CERAMICS:

Ceramics are non-metallic, inorganic materials formed by heating and then cooling natural or
synthetic raw materials. They are characterized by their hardness, brittleness, and resistance to heat
and corrosion. Ceramics are essential in various industries due to their unique properties.

Properties of Ceramics
1. Resistant to wear and abrasion.
2. Excellent thermal stability.
3. Low electrical conductivity
4. High Brittleness
5. Often lightweight compared to metals.
Applications of Ceramics
1. Bricks, tiles, and sanitary ware in the Construction field.
2. Household Items like Pottery, tableware, and decorative items.
3. Insulators, capacitors, and piezoelectric components in the Electronics field
4. Medical field: Dental implants, bone grafts, and prosthetics.
5. Energy: Fuel cells, solar panels, and batteries.

GRAPHITE:

Graphite is a naturally occurring form of crystalline carbon with a layered structure.

Types:
1. Natural Graphite: Found in flake, amorphous, or vein forms.
2. Synthetic Graphite: Manufactured through high-temperature processes.

Properties:
a. Excellent thermal and electrical conductor.
b. High melting point and thermal stability.
c. Resistant to acids and alkalis.
d. Brittle in nature, Fractures under stress.
Applications:
1. In Industries like Lubricants, refractories, and electrodes.
2. Anode material in lithium-ion batteries, fuel cells in the Electronics field
3. Neutron moderator in the Nuclear Reactors
4. Pencils
DIAMOND:

Diamond is the hardest naturally occurring material known because of its covalent bond structure.
Over 70 percent of diamonds are used for industrial applications and demand for the material is
continuously growing.
Natural diamond is carbon crystals that forms under high temperature and pressure conditions that
exist only about 100 miles beneath the earth’s surface.
It is typically about 99.95 percent carbon. The other 0.05 percent can include one or more trace
elements, which are atoms that aren’t part of the diamond’s essential chemistry.

Properties:
1. Hardness
2. Low coefficient of friction
3. High thermal conductivity
4. High electrical resistivity

Applications:
1. Wear components
2. Cutting tools
3. Thermal management (in e.g. substrates, heat spreaders and heat sinks)
4. Semiconductor devices
5. Optical components
6.

SHAPE MEMORY ALLOYS (SMAs):

Shape Memory Alloys are special metallic materials that can return to a predefined shape or size when
subjected to the appropriate thermal procedure. This property is known as the shape memory effect.
Deformation is normally carried out at relatively low temperature, whereas, shape memory effect
happens due to heating.
Common SMAs:
Nickel-Titanium (NiTi): Most widely used for its excellent performance.
Copper-Based Alloys: Copper-Zinc-Aluminum and Copper-Aluminum-Nickel.
Iron-Based Alloys: Iron-Manganese-Silicon.
Applications:

1. Medical Field: Surgical tools, Stents for cardiovascular issues.

2. Aerospace
3. Automotive: Actuators for climate control systems, Vibration dampers.
4. Robotics: Flexible robotic arms.
5. Construction: Earthquake-resistant buildings, Smart structural systems.
6. Consumer Products: Eyeglass frames, Temperature-sensitive safety valves.

JOINING PROCESSES
INTRODUCTION

Certain products cannot be manufactured as a single piece. The desired shape and size of such
products can be obtained by joining two parts of same or different materials.
There are basically 2 ways in which the various materials can be joined. They are:-

Temporary joining processes

This is the kind of joining process in which the joint between the 2 materials is Temporary; which
means that the joint can be removed as and when required. The best examples include screws, bolts
and nuts etc.

Permanent joining processes

These are the joints which are permanent in nature. Once joined, these joints can be removed only by
breaking the joint portion which leads to the physical distortion of the parent materials. E.g.:-
Soldering, Brazing and Welding.

SOLDERING
Soldering is a group of joining process used for joining similar or dissimilar metals by means of a
filler metal whose melting temperature is below 450°C. The filler metal usually called solder is an
alloy of tin and lead in various proportions.

BRAZING
Brazing is a method of joining similar or dissimilar metals by means of a filler metal whose melting
temperature is above 450°C, but below the melting point of the base metal (work piece).
The filler metal called spelter is a non-ferrous metal or alloy. Copper and copper alloys, silver and
silver alloys, and aluminum alloys are the most commonly used filler metals for brazing.
The flow of molten filler material into the gap between the two work pieces is driven by the capillary
force. The filler material cools down and solidifies forming a strong metallurgical joint.
WELDING
It is a process of joining 2 pieces of metal by heating them to a temperature high enough to cause
melting, with or without the application of pressure and with or without the use of filler metal.

Classification of welding processes:

Plastic welding: In plastic welding, the metal parts to be joined are heated to the plastic state, or
slightly above, and then fused together by applying external pressure. No filler metal is used in this
process. Example: Forge welding, Friction welding, resistance welding, etc. Plastic welding is also
called pressure welding process.

Fusion welding: In fusion welding, the parts to be joined are heated above their melting temperatures
and then allowed to solidify by cooling. A filler metal may or may not be used during the welding
process. Example Arc welding, gas welding, Laser welding, etc.

ARC WELDING
Arc welding process is a fusion method of welding that utilizes the high intensity of the arc
generated by the flow of current to melt the work pieces. A solid continuous joint is formed upon
cooling.

Figure shows the arc welding process. In this process, the electrode holder holding the electrode
firmly forms one pole of the electric circuit, while the work piece to be welded forms the other
pole. The electrode serves both to carry the arc and also acts as a filler rod to deposit the molten
metal into the joint.
The electrode used in arc welding process is a metallic wire, which is made of the same material
or nearly the same chemical composition as that of the work piece material. The metallic wire is
coated with a suitable flux material like rutile (titania), calcium fluoride, cellulose, iron oxide,
etc., which gives off gases as it decomposes there by preventing oxidation of the molten metal
during welding process. .
In operation, an arc is struck by touching the tip of the electrode on the work piece (similar to
striking a match stick), and instantaneously the electrode is separated by a small distance of 2-4
mm such that the arc still remains between the electrode and the work piece.
The temperature of the arc ranges from 5000 - 6000°C. The high heat at the tip of the arc melts
the work piece metal forming a small molten metal pool.

At the same time, the tip of the electrode also melts. The molten metal of the electrode is
transferred into the molten metal of the work piece in the form of globules of molten metal.
The deposited metal fills the joint and bonds the joint to form a single piece of metal. The
electrode is moved along the surface to be welded to complete the joint.

GAS WELDING
Gas welding is a fusion welding process in which the work pieces are joined by the heat of a strong
flame generated by the combustion of a fuel gas and oxygen. The fuel gas may be acetylene,
hydrogen, propane, or butane.

OXY-ACETYLENE WELDING:
When oxygen and acetylene are mixed in suitable proportions in a welding torch and ignited, the
flame resulting at the tip of the torch has a temperature ranging from 3200°C- 3500°C, which is
sufficient enough to melt and fuse the work piece metals. Filler metal may or may not be used during the
process. Figure shows the arrangement of the oxy-acetylene welding process

Two large cylinders; one containing oxygen at high pressure, and the other containing acetylene
gas.

Two pressure regulators fitted on the respective cylinders to regulate or control the pressure of the
gas flowing from the cylinders to the welding torch as per the requirements.

Welding torch is used to mix both oxygen and acetylene gas in proper proportions and burn the
mixture at its tip. A match stick or a spark lighter may be used to ignite the mixture at the torch tip.
The resulting flame at the torch tip has a temperature ranging from 3200-3500°C and this heat is
sufficient enough to melt the work piece metal. Since a slight gap usually exists between the two
work pieces, a filler metal may be used to supply the additional material to fill the gap. The molten
metal of the filler metal combines with the molten metal of the work piece, and upon solidification
form a single piece of metal.
Advantages
 Process is simple and inexpensive.
 Eliminates skilled operator.
Disadvantages
 Acetylene gas is slightly costlier.
 Not suitable for thick and high melting point metals.
 Refractory metals like tungsten, molybdenum etc., and reactive metals like
zirconium, titanium, etc., cannot be gas welded.

TYPES OF FLAMES PRODUCED IN OXY-ACETYLENE PROCESS

Three different types of flames can be produced at the torch tip by regulating the ratio of
oxygen to acetylene.
They are:
 Neutral flame - oxygen and acetylene are mixed in equal proportions.
 Oxidizing flame - excess of oxygen
 Reducing flame - excess of acetylene.

Neutral flame:
A neutral flame is produced when approximately equal volumes of oxygen and acetylene are burnt
at the torch tip. All the carbon supplied by acetylene is being consumed and the combustion is
complete. The flame has a nicely defined inner whitish cone surrounded by a sharp blue flame. The
temperature of the neutral flame is around 3260 °C (5900 °F).
Oxidizing flame:
If, after the neutral flame has been established, the supply of oxygen is further increased, the result
will be an oxidizing flame. In other words, it is a flame in which there is more oxygen than is required
for complete combustion. The oxidizing flame appears similar to the neutral flame but with a shorter
inner white cone, and the outer envelope being narrow and brighter in color.
Reducing flame:
If the volume of oxygen supplied to the neutral flame is reduced, the resulting flame will be a
carburizing or reducing flame i.e., rich in acetylene. Combustion is incomplete with unconsumed
carbon being present in the flame.

Distinguish between soldering, brazing and welding:

Welding Brazing Soldering

High temperature process Medium temperature process Low temperature process
Filler metal is optional Filler metal is essential & called Filler metal is required &
spelter
called solder
Poor surface finish Good surface finish Poor surface finish
Welding defects affects No defects Less defects than welding
welding
Flux used is rutile (titania) Flux used is Borox Flux used is zinc chloride
Base metals melts Base metal does not melt Base metal does not melt
Joints are stronger as Joints are stronger than soldering but Joints weaker compared to
compared to soldering and weaker than welding brazing and welding
brazing
Welding using the filler metal In brazing filler metal is having the Soldering using the filler
having the melting point nearly melting point greater than metal having the melting
equal to the base metal 450ºC point less than 450ºC

No capillary action is Joints takes place due to capillary Capillary action is also present
present. Joint takes place action between the base metal and in soldering between the base
due to fusion the filler metal metal and filler metal.
MODULE 5

INTRODUCTION TO MECHATRONICS

The term mechatronics is used for this integration of microprocessor control systems, electrical
systems and mechanical systems.
A mechatronic system is not just a combination of electrical and mechanical systems and is more
than just a control system; it is a complete integration of all of them.

CONTROL SYSTEM
The function of the Control System is to execute the program of instructions and make the
process to carry out a manufacturing operation.
There are basically two types of Control systems:
1. Open Loop Control System
2. Closed Loop Control System

1. Open Loop Control System

An open-loop control system is a type of control mechanism that functions without feedback. The
control action is based solely on the input, and there is no correction or adjustment based on the
output.

Components of an Open-Loop System:

Input: The desired control signal or set point.
Controller: Processes the input signal and generates the command.
Actuator: Converts the command into physical action.
Process: The operation or system being controlled.
Output: The result of the system's operation, not compared to the input.

Examples:

1. Electric Kettle:
2. Automatic Washing Machine:
3. Traffic Lights
4. Conveyor Belts
5. Irrigation Systems:
Advantages:

1. Simplicity in design and implementation.

2. Cost-effective due to fewer components.
3. High-speed operation due to lack of feedback processing.

Disadvantages:

1. Cannot compensate for disturbances or errors.

2. Inaccurate if system parameters vary over time.
3. Unsuitable for systems requiring precise control

2. Closed loop system

A closed-loop control system is a control mechanism that utilizes feedback to compare the actual
output with the desired output. Based on this comparison, the system adjusts its actions to minimize
the error and achieve the desired performance.

Components of a Closed-Loop System:

1. Input (Set Point): The desired output or reference signal.
2. Controller: Processes the input and feedback to generate a corrective command.
3. Actuator: Converts the command signal into a physical action.
4. Process/System: The operation being controlled.
5. Sensor: Measures the actual output.
6. Feedback Path: Returns the actual output measurement to the controller for comparison.

Examples:

1. Thermostat-Based Heating System:

2. Air Conditioning System:
3. CNC Machines:
4. Servo Motors in Robotics:
5. Automatic Cruise Control in Vehicles:
6. Autonomous Drones:
Advantages:
1. High precision and accuracy.
2. Can compensate for external disturbances and system variability.
3. Reliable performance in dynamic conditions.
Disadvantages:
1. More complex design and implementation.
2. Costlier due to additional components like sensors and feedback mechanisms.
3. Slower response time compared to open-loop systems due to feedback processing.

Comparison with Open-Loop System:

Feature Open-Loop System Closed-Loop System

Feedback No Yes
Accuracy Lower Higher
Complexity Simple Complex
Cost Low High
Response Time Fast Slower
Error Correction Not possible Self-correcting

INTRODUCTION TO ROBOTICS

Definition of Robotics

Robotics is the branch of science and engineering that deals with the design, construction, operation,
and application of robots. It involves the integration of mechanical systems, electrical systems, and
computer algorithms to create machines that can perform tasks autonomously or with minimal human
intervention.

Applications of Robotics:

1. Manufacturing: Automation of production lines for efficiency and precision.

2. Healthcare: Surgical assistance, rehabilitation devices, and patient monitoring.
3. Military: Surveillance, bomb disposal, and unmanned combat.
4. Space Exploration: Deployment of robots for planetary exploration and satellite
maintenance.
5. Agriculture: Precision farming, planting, and harvesting robots.
6. Entertainment: Animatronics in movies and theme parks.
7. Transportation: Autonomous vehicles and drones for logistics.
CLASSIFICATION BASED ON ROBOT CONFIGURATION

1. Polar or Spherical configuration.

2. Cylindrical configuration.
3. Cartesian coordinate robot.
4. Jointed – arm robot.

1. Polar or Spherical configuration.

Spherical Configuration is a type of robot configuration in which the robot arm operates within a
spherical workspace. This configuration is based on a combination of rotational and linear motions to
position and orient the end effector.

Advantages:
1. Large working volume compared to its size.
2. Efficient for tasks requiring a wide range of motion.
3. Simplified motion control for spherical spaces.
Disadvantages:
1. Complex mechanical design.
2. Reduced precision compared to Cartesian configurations.
3. Limited load-carrying capacity for some designs.
Applications of Spherical Robots:
1. Pick-and-Place Operations
2. Inspection Tasks
3. Medical Applications
4. Aerospace:
 2. Cylindrical configuration.

Cylindrical Configuration refers to a robot design where the working area is shaped like a cylinder.
This configuration combines rotary and linear motions, enabling the robot to perform tasks in a
cylindrical workspace.

Advantages:
1. Simplified Design.
2. Large Reach.
3. Space Efficiency.

Disadvantages:
1. Limited ability to handle complex tasks requiring multiple axes of movement.
2. Restricted workspace compared to articulated configurations.
3. Reduced flexibility for certain applications.

Applications of Cylindrical Configuration:

1. Material Handling.
2. Assembly Lines.
3. Welding.
4. Painting.
5. Inspection Tasks.
 3. Cartesian coordinate robot.

Cartesian Configuration refers to a robotic system where the robot operates within a rectangular,
three-dimensional coordinate system (X, Y, Z axes). This configuration uses linear actuators along
the Cartesian coordinates to achieve motion.

Advantages:
1. High Accuracy.
2. Simple Programming.
3. Rigid Structure.
4. Customizable Workspace: Modular design allows scalability in the X, Y, and Z directions.

Disadvantages:
1. Limited range of motion outside its rectangular workspace.
2. Requires a large footprint for operation.
3. Limited flexibility in tasks requiring complex or angular movements.

Applications of Cartesian Configuration:

1. 3D Printing.
2. CNC Machines.
3. Pick-and-Place Operations.
4. Assembly Lines.
5. Inspection and Testing.
 4. Jointed – arm robot or Articulated configuration.

Jointed – arm robot Articulated Configuration refers to a robot design characterized by its rotary
joints, which provide multiple degrees of freedom (DOF). This configuration closely resembles the
movement of a human arm, making it highly flexible and suitable for complex tasks.
Advantages:
1. High Flexibility.
2. Compact Design.
3. Versatile Applications.

Disadvantages:
1. Complex Programming:
2. Higher Cost.
3. Increased Maintenance.

Applications of Articulated Configuration:

1. Industrial Automation.
2. Medical Field.
3. Pick-and-Place Operations.
4. Painting and Coating.
5. Aerospace and Automotive.
AUTOMATION
Automation is a technology concerned with the application of mechanical, electronic, and
computer-based systems to operate and control production activities with little or no human’s
intervention.

Types of automation

Automated manufacturing system can be classified into three basic types:

1) Fixed automation (Hard automation)
2) Programmable automation (Soft automation)
3) Flexible automation

1. Fixed automation (Hard automation)

Fixed Automation, also known as Hard Automation, refers to a type of manufacturing system where
the equipment is specifically designed to perform a fixed sequence of operations for high-volume
production. The system is not easily reconfigured, making it most effective for tasks that require
consistent and repetitive operations.
Advantages
1. High Efficiency
2. Low Per-Unit Cost
3. Consistency and Accuracy

Disadvantages
1. Inflexibility
2. High Initial Cost
3. Maintenance Challenges
 2. Programmable automation (Soft automation)

Programmable Automation, often referred to as Soft Automation, is a type of automation system

designed to handle a variety of tasks by reprogramming the equipment. It is more flexible than fixed
automation and is suitable for batch production or tasks where product configurations vary over
time.

Advantages

1. Flexibility
2. Cost-Effective for Varied Production
3. Efficient Changeover
4. Reduced Downtime

Disadvantages

1. Higher Initial Cost

2. Programming Complexity
3. Slower Production Rate

3. Flexible automation

Flexible Automation is an advanced type of automation system that combines the adaptability of
programmable automation with the efficiency of fixed automation. It is designed to handle multiple
product variations without significant downtime for reprogramming or reconfiguration.

Advantages:
1. High Flexibility
2. Efficient Use of Resources
3. Rapid Changeover
4. Long-Term Cost Effectiveness
Disadvantages:
1. High Initial Cost
2. Complexity in Setup
3. Not Suitable for Small Batches