Manufacturing Processes
Chapter 1:
Introduction
Dr. Yazan Al-Zain
Department of Industrial Engineering
University of Jordan, Amman-Jordan
What is Manufacturing??
• The word manufacturing is centuries old and
derived from two Latin words manus (hand) and
factus (make); the combination means by hand.
Hence manufacturing literally means made by
hand.
• Although modern manufacturing is
accomplished by automated and computer-
controlled machinery the word manufacturing is
still in use.
Manufacturing Defined
• Manufacturing can be defined in two ways; technologically and
economically.
• In technology, manufacturing is the application of physical and
chemical processes to alter the geometry, properties, and/or
appearance of a starting material to make products. Manufacturing
also includes assembly of multiple parts to make products.
• In economy, manufacturing is the transformation of materials into
items of greater value by means of one or more processing and/or
assembly operations.
• The key point is that manufacturing adds value to the material
either by changing its shape or properties or by combining it with
other materials that have been similarly altered.
Manufacturing Defined
Figure 1.1 (a) Manufacturing
as a technical process
Figure 1.1 (b) Manufacturing
as an economic process
Manufacturing Industries and
Products
• Manufacturing is important to our lives. Yet, we do not manufacture
stuff just for the sake of manufacturing. We manufacture because
we want to make money!
• Industries in manufacturing is divided into three major categories;
Primary, Secondary and Tertiary Industries.
1. Primary industries are those that cultivate and exploit natural
resources, such as agriculture and mining.
2. Secondary industries are those that take the outputs of the primary
industries and convert them into consumer and capital goods. (This
type is of our concern because it is engaged directly in
manufacturing).
3. Tertiary industries constitute the service sector of the economy..
Manufacturing Industries and
Products
• Manufactured products: Final products by industries
such as Aerospace, Automotive, Basic Metals,
Computers, Electronics, Glass, Ceramics can be
divided into two major classes:
1. Consumer goods: Products purchased directly by
consumers, such as cars, PCs, TVs, etc.
2. Capital goods: Products purchased by other
companies to produce goods and supply services,
such as aircrafts, mainframe computers, railroad
equipment, machine tools, construction equipment,
etc.
Manufacturing Industries and
Products
• Production Quantity (Q) and Product Variety (V).
1. The quantity of products made by a factory has a great influence on the
way its people, facilities and procedures are organized. Annual
production can be classified into 3 ranges:
- Low production: quantities in the range 1 to 100 units/year.
- Medium production: from 100 to 10,000 units/year.
- High production: 10,000 to millions of units/year. However and
depending on the kinds of products, these ranges may shift by an order
of magnitude or so.
2. The product variety: since some factories specialize in high production of
only one product type while other factories produce a variety of products
each type being made in low or medium quantities, it is instructive to
identify product variety as a parameter distinct from production quality. It
is logical to consider factories with a high number of product types to
have high product variety.
Manufacturing Industries and
Products
• There is an inverse correlation between production quantity and
product variety. The higher the production quantity the lower the
product variety and vise versa.
• Manufacturing plants tend to specialize in a combination of Q and V
that lies somewhere inside the diagonal band in the figure.
Figure 1.2 Relationship
between Q and V.
Manufacturing Industries and
Products
• Although V is a quantitative parameter, it is much less
exact than Q because details on how much the
designs differ is not captured simply by the number of
different designs.
1. Soft product variety: small differences between
products, e.g., between car models made on the same
production line, with many common parts among
models.
2. Hard product variety: products differ substantially, e.g.,
between a small car and a large truck, with few
common parts.
Manufacturing Capability
• A manufacturing plant consists of processes and systems (and
people, of course) designed to transform a certain limited range of
materials into products of increased value.
• Modern manufacturing consists of three main blocks; materials,
processes, and systems.
• Manufacturing capability can be defined as the technical and
physical limitations of a manufacturing firm and each of its plants.
• Dimensions of capability are: Technological Processing Capability,
Physical Product Limitations and Production Capacity.
Manufacturing Capability
• Technological Processing Capability (TPC): a plant’s TPC is its
available set of manufacturing processes. The type of
manufacturing processes defines the type of the plant, e.g. A
machine shop can build cars while a rolling mill can roll steel but not
the other way around!
- Certain manufacturing processes are suited to certain materials,
while other processes are suited to other materials.
- TPC includes not only the physical processes but also the expertise
possessed by the plant personnel in these processing technologies.
- Companies must concentrate on the design and manufacture of
products that are compatible with their TPC.
Manufacturing Capability
• Physical Product Limitations: A plant with a given set of process is
restricted to certain weight and size limitations. e.g. Large and
heavy items are difficult to move, to move them the plant must be
equipped with cranes, while small items made in large quantities
can be moved by conveyor.
- The limitations on product size and weight extends to the physical
capacity of the manufacturing equipment as well. Production
machines come in different sizes. e.g. large machines must be
used to produce large items.
- The set of production equipment, material handling, storage
capability and plant size must be planned for products that lie within
a certain size and weight range.
Manufacturing Capability
• Production Capacity (PC): A third limitation on plant’s
manufacturing capability is the production quantity that
can be produced in a given time period. This quantity
limitation is commonly called Plant Capacity, or
Production Capacity.
- PC is the maximum rate of production that the plant can
achieve under assumed operating conditions (no. of
shifts per week, hours per shift, etc).
- PC is measured in terms of output units, such as annual
tons of steel produced by a steel mill.
Materials in Manufacturing
• Most engineering materials can be classified into one
of the three basic categories: (1) Metals, (2) Ceramics
and (3) Polymers.
• They have different chemistries and their mechanical
and physical properties are dissimilar.
• These differences affect the manufacturing processes
that can be used to produce products from them.
• In addition, there are (4) Composites:
nonhomogenious mixtures of the other three basic
types rather than a unique category.
Materials in Manufacturing
• The relationship of the four groups is
pictured in the following figure.
Figure 1.3 Venn diagram of three
basic material types plus composites.
Materials in Manufacturing
[1] Metals: metals used in manufacturing are usually in the form of
alloys (two ore more elements, at least one of which is metallic).
Metals are divided into two basic groups; ferrous and nonferrous.
a. Ferrous metals: based on Iron (Fe) as the major alloying element.
This group includes steel and cast iron.
- More than 75% of the metal tonnage throughout the world.
- Fe has limited commercial use, but when alloyed with carbon (C),
Fe has more use and greater commercial value than any other
metal.
- Fe when alloyed with C forms Steel or Cast Iron.
Materials in Manufacturing
• Steel: Is an Iron-Carbon alloy containing 0.02 to 2.11 wt.
% C.
• Most important category within the ferrous metals group,
due to low cost and good mechanical and physical
properties.
• Its composition contains other metals such as Mg, Cr, Ni,
Mo, etc, to enhance the properties of the alloy.
• Used widely in construction, transportation and
consumer products.
Materials in Manufacturing
• Cast iron: Iron-Carbon alloy containing ~2 to ~4 wt.% C.
• Used primarily in sand casting.
• Other elements such as Si (0.5 to 3 wt.%) is present in
the alloy. Other elements are often added as well.
• Gray cast iron is the most common type of cast iron; its
applications include blocks and heads for internal
combustion engines, manholes covers, etc.
Materials in Manufacturing
b. Nonferrous metals: These include other metallic elements and their
alloys.
• In almost all cases, the alloys are more important commercially
than the pure metals.
• Some examples are Gold alloys, Titanium alloys, Copper alloys, etc.
Materials in Manufacturing
[2] Ceramics: A compound containing metallic (or semimetallic) and
nonmetallic (O, N and C) elements.
• Traditional ceramics: Been used for thousands of years. They include: clay
(consists of fine particles of hydrous aluminum silicate and other minerals
used in making brick, tile and pottery); silica (the basis of nearly all glass
products); and alumina and silicon carbide (abrasive materials used in
grinding).
• Modern ceramics: Consists of alumina of enhanced properties. Newer
ceramics include carbides, metal carbides such as tungsten and titanium
carbides (used as cutting tool materials); and nitrides (e.g. titanium nitride
and boron nitride, used as cutting tools and grinding abrasives).
• For processing purposes, ceramics can be divided into (1) crystalline
ceramics and (2) amorphous ceramics (glasses). The former are formed in
various ways from powders and then sintered, while the later can be
melted and cast and then formed (e.g. glass blowing).
Materials in Manufacturing
[3] Polymers: A compound formed of repeating structural units
called mers, whose atoms share electrons to form very large
molecules. They consist of carbon plus one or more other elements
such as hydrogen, oxygen, nitrogen and chlorine. They are divided
into three categories:
• Thermoplastic polymers: can be subjected to multiple heating and
cooling cycles without altering molecular structure; e.g.
polyethylene, polystyrene, polyvinylchloride and nylon.
• Thermosetting polymers: molecules chemically transform (cure) into
a rigid structure upon cooling from a heated plastic condition; e.g.
epoxies and amino resins.
• Elastomers: they exhibit significant elastic behavior; e.g. silicon and
rubber.
Materials in Manufacturing
[4] Composites: A mixtures of the other three basic types. A composite is a
material consisting of two or more phases that are processed separately and then
bonded together to achieve properties superior to its constituents.
• Phase: Homogeneous mass of material, such as grains of identical unit cell structure
in a solid metal.
• The usual structure of a composite material consists of particles or fibers of one
phase mixed in a second phase, called the matrix.
• Composites are found in nature (wood) and they can be produced synthetically (fiber-
reinforced plastic).
• Properties depend on its components, physical shapes of components, and the way
they are combined to form the final material. Some composites combine high
strength and light weight and are used as aircraft components, car bodies, etc. Other
composites are strong and hard, and capable of maintaining these properties at high
temperatures; e.g. cemented carbide cutting tools.
Manufacturing Processes
• Manufacturing processes can be divided into two
basic types:
1. Processing operations: transforms a work material
from one state of completion to a more advanced
state closer to the final desired product. It adds value
by changing geometry, properties or appearance of
the starting material.
2. Assembly operations: joins two or more components
in order to create a new entity called an assembly,
subassembly, etc.
Manufacturing Processes
Figure 1.4
Classification of
manufacturing
processes
Manufacturing Processes
• Processing operations: use energy to alter a workpart’s shape,
physical properties or appearance in order to add value to the
material. There are three categories of processing operations:
1. Shaping operations: alter the geometry of the work material by
methods including casting, forging and machining.
2. Property-enhancing operations: add value to the material by
improving its physical properties without changing its shape; e.g.
Heat treatment.
3. Surface processing operations: performed to clean, treat, coat or
deposit material onto the exterior surface of the work. Examples
for coating are plating and painting.
Manufacturing Processes
• Shaping processes: change the geometry of a work material by
application of heat or mechanical force or a combination of both.
It can be classified into four categories:
1. Solidification processes: the starting material is a heated liquid or
semifluid that cools or solidifies to form the part geometry.
2. Particulate processing: the starting material is a powder, and the
powders are formed and heated into the desired geometry.
3. Deformation processes: the starting material is a ductile solid that
is deformed to shape the part.
4. Material removal processes: the starting material is a solid, from
which material is removed so that the resulting part has the
desired geometry.
Manufacturing Processes
• Solidification process: starting material is
heated sufficiently to transform it to the liquid
state. With the material (metals, plastics and
ceramic glasses) in the liquid state, it can be
poured into a mold cavity and allowed to solidify
, thus taking a solid shape that is the same as
the cavity.
Figure 1.5 Casting
(metals) and molding
(plastics) processes.
Manufacturing Processes
• Particulate processing: Starting materials are
powders of metals or ceramics. The powders
are then pressed and sintered. The powders are
first squeezed into a die cavity under a high
pressure and then heated to bond the individual
particles together.
Figure 1.6 Particulate processing.
(1) Starting material (2) Pressing
and (3) Sintering.
Manufacturing Processes
• Deformation processes: the starting workpart is
shaped by application of forces that exceed the
yield strength of the material (material must be
ductile enough (accomplished by means of
heating)), this process includes extrusion and
forging.
Figure 1.7 Deformation processes (a) forging (b) extrusion
Manufacturing Processes
• Material removal processes: operations that remove
excess material from the starting workpart to get the
desired geometry. Most common processes in this
category include machining and grinding. The former
includes turning, drilling and milling. Other special
processes are known as nontraditional processes as
they use lasers, electron beams, electric discharge, etc.
Figure 1.8 Material removal processes. (a) turning (b) drilling and (c) milling.
Manufacturing Processes
• Waste: it is desirable to minimize the waste and scrap in
converting a starting workpart into a desired geometry.
- Material removal processes tend to be wasteful of
material, simply by the way they work.
- Solidification processes convert close to 100% of the
starting material into final product, such processes are
called net shape processes, while other processes that
require minimum machining to produce the final shape
are called near net shape processes.
Manufacturing Processes
• Property enhancing processes:
performed to improve mechanical or
physical properties of the work material
(no shape altering). The most important
processes involve heat treatments,
which includes various annealing and
strengthening processes for metals and
ceramics.
Manufacturing Processes
• Surface processing: this process includes:
1. Cleaning: includes both chemical and mechanical processes to
remove dirt, oil and other contaminants from the surface.
2. Surface treatments: includes mechanical working such as sand
blasting and physical processes such as diffusion and ion
implantation.
3. Coating and thin film deposition: apply a coating of material to the
exterior surface of the workpart, examples are painting (organic
coating) and electroplating. Thin film deposition in the other hand
include physical and chemical vapor deposition to form extremely
thin coatings of various substances.
Manufacturing Processes
• Assembly operations: second basic type of
manufacturing operations, in which two parts or more
are joined permanently or semipermanently to form a
new entity.
- Permanent joining includes welding, soldering, adhesive
bonding, etc.
- Mechanical assembly fastens parts in a joint that can be
conveniently disassembled (using threaded fasteners
such as bolts, rivets, nuts, etc).
Manufacturing Processes
• Production machines and tooling: manufacturing
operations are accomplished using machinery and
tooling (and people of course).
- Machine tools: power-driven machines used to operate
cutting tools previously operated by hand. Used not only
to make parts for consumer products, but also
components for other production machines. The
machine tool is the mother of all machinery.
- Other production machines include presses for
stamping operations, forge hammers for forging, rolling
mills for rolling sheet steel, welding machines for
welding, etc.
Manufacturing Processes
• Production equipment can be divided into two
categories:
- General purpose equipment: more flexible and
adaptable for a variety of jobs.
- Special purpose equipment: designed to produce a
specific part in large quantities.
* Production machinery usually requires tooling, which
customizes the equipment for the particular part or
product. Hence, the type of tooling depends on
manufacturing process (see table).
Manufacturing Processes
Process Equipment Special Tooling (Function)
Casting Various setups and equipment Mold (cavity for molten metal)
Molding Molding machines Mold (cavity for molten polymer)
Rolling Rolling mill Roll (reduce work thickness)
Forging Forge hammer/press Die (squeeze work shape)
Extrusion Press Extrusion die (reduce cross section)
Stamping Press Die (shearing, forming sheet metal)
Machining Machine tool Cutting tool (metal removal)
Fixture (hold work part)
Jig (hold part and guide tool)
Grinding Grinding machine Grinding wheel (material removal)
Welding Welding machine Electrode (fusion of work metal)
Fixture (hold parts during welding)
Table: Special tooling used in various operations.
Production Systems
• Production systems: systems that manufacturing firms must have in order
to accomplish its type of production effectively. These systems consist of
people, equipment and procedures designed for the combination of
materials and processes that constitute a firm’s manufacturing operation.
• Production systems can be divided into two categories:
1. Production facilities: the physical equipment and its arrangement in the
factory.
2. Manufacturing support systems: procedures used by the company to
manage production and solve the technical and logistics problems
encountered in ordering materials, moving work through the factory and
ensuring that products meet quality standards.
● Both categories include people, people make these system work.
Production Systems
• Production facilities: consist of the factory, production equipment
and material handling equipment.
• The equipment comes in direct contact with the part being made.
• The facilities “touch” the product and include the way the equipment
is arranged in the factory (the plant layout).
• The equipment is usually organized into logical groupings
(manufacturing systems); e.g. automated production line, or a
machine cell consisting of an industrial robot and two machine tools.
• Production facilities have come to be recognized as the most
appropriate way to organize for a given type of manufacturing (the
combination of product variety and production quantity). Hence,
different facilities are required for each of the three quantity ranges.
Production Systems
(1) Low-Quantity Production: This type is described as job shop
(range 1 to 100 units/year). Produces specialized and customized.
The equipment is job shop is general purpose and the labor force is
highly skilled.
• Products are usually complex; e.g. space capsules, prototype
aircrafts and special machinery. If product is large and heavy (say
an aircraft), it remains in its place and the workers and equipment
are brought to the product “fixed position layout”.
• The individual components of these large products (say aircraft
components) are often made in factories in which the equipment is
arranged according to function or type “process layout”.
• Due to hard product variety, a job shop must be designed for
maximum flexibility.
Production Systems
(2) Medium-Quantity Production: (range 100 to 10,000 units/year). Two
approaches depending on the product variety:
- Batch production:
* in case of hard product variety.
* a batch of one product is made.
* when the batch is produced, the manufacturing system is changed over to
produce a batch of the next product. (disadvantage: time wasting as setup time is
required).
* commonly used for make-to-stock situations, in which items are manufactured to
replenish inventory (compensate for products) that has been gradually depleted by
demand.
* The equipment is usually arranged in a process layout.
Production Systems
- Cellular manufacturing:
* in case of soft product variety.
* excessive changeovers are not necessary (less time wasted
compared to batch production).
* called cellular since the processing or assembly of different parts
is accomplished in cells consisting of several work stations or
machines.
* the cellular manufacturing uses cellular layout (group technology
layout).
Production Systems
(3) High Production: referred to as Mass Production (range
10,000 to millions of units/year). Two categories of mass production can be
categorized:
- Quantity production:
* involves the mass production of single parts on single pieces of
equipment.
* it involves standard machines (such as stamping presses) equipped with
special tooling (e.g. dies and material handling devices).
* hence, dedicating the equipment to the production of one part type.
* Typical layouts used in quantity production are the process layout and
cellular layout.
Production Systems
- Flow line production:
* involves multiple pieces of equipment or workstations arranged in
sequence, and the work units are physically moved through the sequence
to complete the product.
* the layout is called product layout, and the workstations are arranged
into one long line, or into a series of connected line segments.
* e.g. the assembly line associated with products such as cars and
household appliances.
* flow line productions can be classed into a single-model production
line and a mixed-model production line. The former is the most familiar
example of flow line production, where in the pure case of flow line
production there is no variation in the products, while in the later, there is
soft variety in the products made on the line
Production Systems
• Manufacturing Support Systems (MSS): A company must organize itself to
design the processes and equipment, plan and control production, and
satisfy product quality requirements.
• These functions are accomplished by MSS, people and procedures by
which a company manages its production operations.
• MSS are carried out by people organized into departments such as the
following:
1. Manufacturing engineering: responsible for (a) planning the
manufacturing processes and (b) designing and ordering the machine tools.
2. Production planning and control: responsible for solving the logistics
problems in manufacturing.
3. Quality control: making sure that products are of high quality.
