MANUFACTURING PROCESS
PAPER MAKING PROCESS
Fundamental of Manufacturing Process
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Basic Manufacturing Process
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Introduction to
Basic Manufacturing
Processes and
Workshop Technology
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1.1 INTRODUCTION
Manufacturing is the backbone of any industrialized nation. Manufacturing and technical staff
in industry must know the various manufacturing processes, materials being processed, tools
and equipments for manufacturing different components or products with optimal process
plan using proper precautions and specified safety rules to avoid accidents. Beside above, all
kinds of the future engineers must know the basic requirements of workshop activities in
term of man, machine, material, methods, money and other infrastructure facilities needed
to be positioned properly for optimal shop layouts or plant layout and other support services
effectively adjusted or located in the industry or plant within a well planned manufacturing
organization.
The complete understanding of basic manufacturing processes and workshop technology
is highly difficult for any one to claim expertise over it. The study deals with several aspects
of workshops practices also for imparting the basic working knowledge of the different
engineering materials, tools, equipments, manufacturing processes, basic concepts of electromechanical controls of machine tools, production criteria’s, characteristics and uses of various testing instruments and measuring or inspecting devices for checking components or products manufactured in various manufacturing shops in an industrial environment.
It also describes and demonstrates the use of different hand tools (measuring, marking, holding and supporting tools, cutting etc.), equipments, machinery and various methods of manufacturing that facilitate shaping or forming the different existing raw materials into suitable usable forms. It deals with the study of industrial environment which involves the practical knowledge in the area
of ferrous and non ferrous materials, their properties and uses. It should provide the knowledge
of basic workshop processes namely bench work and fitting, sheet metal, carpentry, pattern
making, mould making, foundry, smithy, forging, metal working and heat treatment, welding,
fastening, machine shop, surface finishing and coatings, assembling inspection and quality
control. It emphasizes on basic knowledge regarding composition, properties and uses of
different raw materials, various production processes, replacement of or improvement over
a large number of old processes, new and compact designs, better accuracy in dimensions,
quicker methods of production, better surface finishes, more alternatives to the existing
materials and tooling systems, automatic and numerical control systems, higher mechanization
and greater output.
1.2 SCOPE OF STUDY
Today’s competitive manufacturing era of high industrial development and research, is being
called the age of mechanization, automation and computer integrated manufacturing. Due to
new researches in the manufacturing field, the advancement has come to this extent that
every different aspect of this technology has become a full-fledged fundamental and advanced
study in itself. This has led to introduction of optimized design and manufacturing of new
products. New developments in manufacturing areas are deciding to transfer more skill to the
machines for considerably reduction of manual labor. The scope of the subject of workshop
technology and manufacturing practices is a extremely wide as it specifies the need of greater
care for man, machine, material and other equipments involving higher initial investment by
using proper safety rule and precautions. The through and deep knowledge in the course of
study of this important subject is therefore becoming essential for all kinds of engineers to
have sound foundation in their profession. Therefore the course of study of this subject
provides a good theoretical background and a sound practical knowledge to the engineering
students and workshop staff. One should also be aware of the following terms for better
understanding of the scope of the study
1.3 MANUFACTURING ENGINEERING
Manufacturing is derived from the Latin word manufactus, means made by hand. In modern
context it involves making products from raw material by using various processes, by making
use of hand tools, machinery or even computers. It is therefore a study of the processes
required to make parts and to assemble them in machines. Process Engineering, in its
application to engineering industries, shows how the different problems related to development
of various machines may be solved by a study of physical, chemical and other laws governing
the manufacturing process. The study of manufacturing reveals those parameters which can
be most efficiently being influenced to increase production and raise its accuracy. Advance
manufacturing engineering involves the following concepts—
1. Process planning.
2. Process sheets.
3. Route sheets.
4. Tooling.
5. Cutting tools, machine tools (traditional, numerical control (NC), and computerized
numerical control (CNC).
6. Jigs and Fixtures.
7. Dies and Moulds.
8. Manufacturing Information Generation.
9. CNC part programs.
10. Robot programmers.
11. Flexible Manufacturing Systems (FMS), Group Technology (GT) and Computer
integrated manufacturing (CIM).
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1.4 PRODUCTION PROCESS
It is the process followed in a plant for converting semi- finished products or raw materials
into finished products or raw materials into finished products. The art of converting raw
Introduction 3
material into finished goods with application of different types of tools, equipments, machine
tools, manufacturing set ups and manufacturing processes, is known as production. Generally
there are three basic types of production system that are given as under.
1. Job production
2. Batch production
3. Mass production
Job production comprises of an operator or group of operators to work upon a single job
and complete it before proceeding to the next similar or different job. The production
requirement in the job production system is extremely low. It requires fixed type of layout
for developing same products.
Manufacturing of products (less in number say 200 to 800) with variety of similar parts
with very little variation in size and shape is called batch production. Whenever the production
of batch is over, the same manufacturing facility is used for production of other batch product
or items. The batch may be for once or of periodical type or of repeated kinds after some
irregular interval. Such manufacturing concepts are leading to GT and FMS technology.
Manufacturing of products in this case requires process or functional layout.
Where as mass production involves production of large number of identical products (say
more than 50000) that needs line layout type of plant layout which is highly rigid type and
involves automation and huge amount of investment in special purpose machines to increase
the production.
1.5 PROCESS PLANNING
Process planning consists of selection of means of production (machine-tools, cutting tools,
presses, jigs, fixtures, measuring tools etc.), establishing the efficient sequence of operation,
determination of changes in form, dimension or finish of the machine tools in addition to the
specification of the actions of the operator. It includes the calculation of the machining time,
as well as the required skill of the operator. It also establishes an efficient sequence of
manufacturing steps for minimizing material handling which ensures that the work will be
done at the minimum cost and at maximum productivity. The basic concepts of process
planning are generally concerned with the machining only. Although these concepts may also
be extended to other processes such as casting, forging, sheet metal forming, assembling and
heat treatment as well.
1.6 MANUFACTURING PROCESS
Manufacturing process is that part of the production process which is directly concerned
with the change of form or dimensions of the part being produced. It does not include the
transportation, handling or storage of parts, as they are not directly concerned with the
changes into the form or dimensions of the part produced.
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1.7 CLASSIFICATION OF MANUFACTURING PROCESSES
For producing of products materials are needed. It is therefore important to know the
characteristics of the available engineering materials. Raw materials used manufacturing of
products, tools, machines and equipments in factories or industries are extracted from ores.
The ores are suitably converted the metal into a molten form by reducing or refining processes
4 Introduction to Basic Manufacturing Processes and Workshop Technology
in foundries. This molten metal is poured into moulds for providing commercial castings,
called ingots. Such ingots are then processed in rolling mills to obtain market form of
material supply in form of bloom, billets, slabs and rods. These forms of material supply are
further subjected to various manufacturing processes for getting usable metal products of
different shapes and sizes in various manufacturing shops. All these processes used in
manufacturing concern for changing the ingots into usable products may be classified into six
major groups as primary shaping processes, secondary machining processes, metal forming
processes, joining processes, surface finishing processes and processes effecting change in
properties. These are discussed as under.
1.7.1 Primary Shaping Processes
Primary shaping processes are manufacturing of a product from an amorphous material.
Some processes produces finish products or articles into its usual form whereas others do not,
and require further working to finish component to the desired shape and size. Castings need
re-melting of scrap and defective ingots in cupola or in some other melting furnace and then
pouring of the molten metal into sand or metallic moulds to obtain the castings. Thus the
intricate shapes can be manufactured. Typical examples of the products that are produced by
casting process are machine beds, automobile engines, carburetors, flywheels etc. The parts
produced through these processes may or may not require to under go further operations.
Some of the important primary shaping processes is:
(1) Casting, (2) Powder metallurgy, (3) Plastic technology, (4) Gas cutting, (5) Bending and
(6) Forging.
1.7.2. Secondary or Machining Processes
As large number of components require further processing after the primary processes. These
components are subjected to one or more number of machining operations in machine shops,
to obtain the desired shape and dimensional accuracy on flat and cylindrical jobs. Thus, the
jobs undergoing these operations are the roughly finished products received through primary
shaping processes. The process of removing the undesired or unwanted material from the
workpiece or job or component to produce a required shape using a cutting tool is known as
machining. This can be done by a manual process or by using a machine called machine tool
(traditional machines namely lathe, milling machine, drilling, shaper, planner, slotter). In
many cases these operations are performed on rods, bars and flat surfaces in machine shops.
These secondary processes are mainly required for achieving dimensional accuracy and a very
high degree of surface finish. The secondary processes require the use of one or more
machine tools, various single or multi-point cutting tools (cutters), job holding devices, marking
and measuring instruments, testing devices and gauges etc. for getting desired dimensional
control and required degree of surface finish on the workpieces. The example of parts produced
by machining processes includes hand tools machine tools instruments, automobile parts,
nuts, bolts and gears etc. Lot of material is wasted as scrap in the secondary or machining
process. Some of the common secondary or machining processes are—
(1) Turning, (2) Threading, (3) Knurling, (4) Milling, (5) Drilling, (6) Boring, (7) Planning,
(8) Shaping, (9) Slotting, (10) Sawing, (11) Broaching, (12) Hobbing, (13) Grinding, (14) Gear
cutting, (15) Thread cutting and (16) Unconventional machining processes namely machining
with Numerical Control (NC) machines tools or Computer Numerical Control (CNC) machines
tools using ECM, LBM, AJM, USM setups etc.
Introduction 5
1.7.3 Metal Forming Processes
Forming processes encompasses a wide variety of techniques, which make use of suitable
force, pressure or stresses, like compression, tension and shear or their combination to cause
a permanent deformation of the raw material to impart required shape. These processes are
also known as mechanical working processes and are mainly classified into two major categories
i.e., hot working processes and cold working processes. In these processes, no material is
removed; however it is deformed and displaced using suitable stresses like compression,
tension, and shear or combined stresses to cause plastic deformation of the materials to
produce required shapes. Such processes lead to production of directly usable articles which
include kitchen utensils, rods, wires, rails, cold drink bottle caps, collapsible tubes etc. Some
of the important metal forming processes are:
Hot working Processes
(1) Forging, (2) Rolling, (3) Hot spinning, (4) Extrusion, (5) Hot drawing and (6) Hot spinning.
Cold working processes
(1) Cold forging, (2) Cold rolling, (3) Cold heading, (4) Cold drawing, (5) Wire drawing,
(6) Stretch forming, (7) Sheet metal working processes such as piercing, punching, lancing,
notching, coining, squeezing, deep drawing, bending etc.
1.7.4 Joining Processes
Many products observed in day-to-day life, are commonly made by putting many parts together
may be in subassembly. For example, the ball pen consists of a body, refill, barrel, cap, and
refill operating mechanism. All these parts are put together to form the product as a pen.
More than 800 parts are put together to make various subassemblies and final assembly of
car or aero-plane. A complete machine tool may also require to assemble more than 100 parts
in various sub assemble or final assembly. The process of putting the parts together to form
the product, which performs the desired function, is called assembly. An assemblage of parts
may require some parts to be joined together using various joining processes. But assembly
should not be confused with the joining process. Most of the products cannot be manufactured
as single unit they are manufactured as different components using one or more of the above
manufacturing processes, and these components are assembled to get the desired product.
Joining processes are widely used in fabrication and assembly work. In these process two or
more pieces of metal parts are joined together to produce desired shape and size of the
product. The joining processes are carried out by fusing, pressing, rubbing, riveting, screwing
or any other means of assembling. These processes are used for assembling metal parts and
in general fabrication work. Such requirements usually occur when several pieces are to be
joined together to fabricate a desired structure of products. These processes are used developing
steam or water-tight joints. Temporary, semi-permanent or permanent type of fastening to
make a good joint is generally created by these processes. Temporary joining of components
can be achieved by use of nuts, screws and bolts. Adhesives are also used to make temporary
joints.
Some of the important and common joining processes are:
(1) Welding (plastic or fusion), (2) Brazing, (3) Soldering, (4) Riveting, (5) Screwing,
(6) Press fitting, (7) Sintering, (8) Adhesive bonding, (9) Shrink fitting, (10) Explosive welding,
(11) Diffusion welding, (12) Keys and cotters joints, (13) Coupling and (14) Nut and bolt joints.
1.7.5 Surface Finishing Processes
Surface finishing processes are utilized for imparting intended surface finish on the surface
of a job. By imparting a surface finishing process, dimension of part is not changed functionally;
6 Introduction to
Basic Manufacturing Processes and Workshop Technology
either a very negligible amount of material is removed from the certain material is added to
the surface of the job. These processes should not be misunderstood as metal removing
processes in any case as they are primarily intended to provide a good surface finish or a
decorative or protective coating on to the metal surface. Surface cleaning process also called
as a surface finishing process. Some of the commonly used surface finishing processes are:
(1) Honing, (2) Lapping, (3) Super finishing, (4) Belt grinding, (5) Polishing, (6) Tumbling,
(7) Organic finishes, (8) Sanding, (9) deburring, (10) Electroplating, (11) Buffing, (12) Metal
spraying, (13) Painting, (14) Inorganic coating, (15) Anodizing, (16) Sheradising, (17) Parkerizing,
(18) Galvanizing, (19) Plastic coating, (20) Metallic coating, (21) Anodizing and (22) Sand blasting.
1.7.6 Processes Effecting Change in Properties
Processes effecting change in properties are generally employed to provide certain specific
properties to the metal work pieces for making them suitable for particular operations or use.
Some important material properties like hardening, softening and grain refinement are needed
to jobs and hence are imparted by heat treatment. Heat treatments affect the physical
properties and also make a marked change in the internal structure of the metal. Similarly
the metal forming processes effect on the physical properties of work pieces Similarly shot
peening process, imparts fatigue resistance to work pieces. A few such commonly used processes
are given as under:
(1) Annealing, (2) Normalising, (3) Hardening, (4) Case hardening, (5) Flame hardening,
(6) Tempering, (7) Shot peeing, (8) Grain refining and (9) Age hardening.
In addition, some allied manufacturing activities are also required to produce the finished
product such as measurement and assembly.
1.8. PRODUCT SIMPLIFICATION AND STANDARDISATION
The technique of simplification and standardization of product is closely inter-related that
leads to higher efficiency in production, better quality and reduced production cost. Simplification
is a process of determining limited number of grades, types and sizes of a components or
products or parts in order to achieve better quality control, minimize waste, simplify production
and, thus, reduce cost of production. By eliminating unnecessary varieties, sizes and designs,
simplification leads to manufacture identical components or products for interchangeability
and maintenance purposes of assembly of parts. Standardization is the important step towards
interchangeable manufacture, increased output and higher economy. The technique of
standardization comprises of determining optimal manufacturing processes, identifying the
best possible engineering material, and allied techniques for the manufacture of a product and
adhering to them very strictly so long as the better standards for all these are not identified.
Thus definite standards are set up for a specified product with respect to its quality, required
equipment, machinery, labor, material, process of manufacture and the cost of production.
The identified standard with time for a specified product should never be taken as final for
ever because improvement is always possible. It must accommodate the outcome of all the
new researches in the manufacturing areas in order to keep pace with increasing global
competition. Improvements over the existing standards in all respects should always be
welcomed. The different standards prevailing in different industries may be of the types of
managerial, design, manufacturing and technical needs. Managerial standards are applicable
to administrative functions within industry. These include the company policy, accounting
procedures, personnel policies, performance evaluation, control of expenditures, safety aspects,
security procedures and regulations, etc. where as design, manufacturing and technical standards
are needed for manufacturing concepts of the industry. These include design and manufacturing
techniques, practices, materials and parts, supplies, methods of testing, drafting method,
abbreviations and symbols, specifications and nomenclature, etc.
1.9 INSPECTION AND QUALITY CONTROL
A product is manufactured to perform desired functions. It must have a specified dimension
such as length, width, height, diameter and surface smoothness to perform or accomplish its
intended function. It means that each product requires a defined size, shape and other
characteristics as per the design specifications. For manufacturing the product to the specified
size, the dimensions should be measured and checked during and after the manufacturing
process. It involves measuring the size, smoothness and other features, in addition to their
checking. These activities are called measurement and inspection respectively.
In the era of globalization, every industry must pay sufficient attention towards maintaining
quality because it is another important requirement or function of a production unit. If a
manufacturing concern wants to survive for longer time and to maintain its reputation among
the users, it should under all condition apply enough efforts not only to keep up the standard
of quality of its products once established but to improve upon the same from time to time.
For this, every manufacturing concern must maintain a full-fledged inspection and quality
control department which inspects the product at different stages of its production. Vigilant
inspection of raw materials and products depends upon the entire process of standardization.
The production unit of manufacturing concern must produce identical products. However a
minor variation may be allowed to a predetermined amount in their finished dimensions of
the products. The two extremities of dimensions of the product are called limits. All the parts
of which the finished dimensions lie within these limits are acceptable parts. This facilitates
easy and quicker production, easy inspection, requires less skill on the part of worker and
accommodates a slight inaccuracy in the machine as well, resulting in an over all reduction
in the production cost of the part.
1.10 MECHANIZATION AND AUTOMATION
Mechanization means something is done or operated by machinery and not by hand.
Mechanization of the manufacturing means is milestone oriented trend towards minimizing
the human efforts to the extent of its possibility, by adopting mechanical and electrical means
or methods for automating the different manufacturing processes. Such a trend may be in the
area of automating and mechanizing the processes of material handling, loading and unloading
of components, actual operations performed on the job or transportation, etc. But, no feedback
is provided by the process, operation or machinery. Extension of mechanization of the production
process is termed as automation and it is controlled by a closed loop system in which feedback
is provided by the sensors. It controls the operations of different machines automatically. The
automatic control may be applied for some operations or for all the operations of a machine
or group of machines. Accordingly the machine will be known as semi-automatic or fully
automatic. The term was identified shortly after the World War II at the Ford Motor Company
to describe the automatic handling of materials and parts between the process operations.
The word ‘automation’ is derived from the Greek word automatos meaning self-acting.
Automation can also be defined as the process of following a predetermined sequence of
operations with little or no human intervention, using specialized equipment and devices that
perform and control the manufacturing process. Automation is a word that has many meanings
in the industry today. Automatic machines of all kinds existed long before the term automation
was conceived. But, it should be noted that all automatic machines do not come under the
category of automation. Automation is a technology concerned with the application mechanical,
electronic, and computer based systems to operate and control production.
Every machine should involve some automation, may be to a lesser degree or to a higher
extent to which is mainly governed by economic considerations. Automation means a system
in which many or all of the processes in the production, movement, and inspection of parts
and material are performed under control by the self-operating devices called controllers. This
implies that the essential elements of automation comprise of mechanization, sensing, feedback,
and control devices. The reasons why one should go for automation are:
1. Increased productivity
2. Reduced cost of labor and dependence on labor shortages
3. Improved quality
4. Reduced in-process inventory
5. Reduced manufacturing time
6. Reduced dependence on operator skills
7. Increased safety or reduced risk of humans.
Automation can be classified into three categories, viz.
1. Fixed automation
2. Programmable automation
3. Flexible automation.
1.10.1 Fixed Automation
It is also known as hard automation which is utilized to produce a standardized product such
as gears, nuts and bolts, etc. Even though the operating conditions can be changed, fixed
automation is used for very large quantity production of one or few marginally different
components. Highly specialized tools, devices, equipment, special purpose machine tools, are
utilized to produce a product or a component of a product very efficiently and at high production
rates with as low unit costs as possible relative to other alternative methods of manufacturing.
Cement Manufacturing Process
1.10.2 Programmable Automation
In programmable automation, one can change the design of the product or even change the
product by changing the program. Such technique is highly useful for the low quantity
production of large number of different components. The equipments used for the manufacturing
are designed to be flexible or programmable. The production normally carried out in batches.
1.10.3 Flexible Automation
There is a third category possible between fixed automation and programmable automation
that is called flexible automation using Computer Aided Design (CAD) and Computer Aided
Manufacturing (CAD/CAM) activities. This is also called as flexible manufacturing system
(FMS). It allows producing different products on the same equipment in any order or mix. One
important example of programmable automation, in discrete manufacturing, is numerical
control. Robot is another example of programmable automation. Robot being integral part of
FMS and Computer Integrated Manufacturing (CIM) system can do a large number of
manufacturing tasks for replacing the human labor.
In the present globalized manufacturing scenario, the advancements of hardware and
software concepts using the mechatronics for fast mechanization and automation of
manufacturing processes have become essential to be incorporated in the manufacturing
areas.
1.11 COMPUTER AIDED MANUFACTURING (CAM)
The computer aided manufacturing implies manufacturing itself, aided or controlled by
computers. In a wider sense, it denotes all the activities in the manufacturing environment
like use of computers in inventory control, project management, material requirement planning,
data acquisition, testing and quality control. Improved reliability in view of the better
manufacturing methods and controls at the manufacturing stage, the products thus
manufactured as well as of the manufacturing system would be highly reliable. Since most
of the components of a CAM system would include integrated diagnostics and monitoring
facilities, they would require less maintenance compared to the conventional manufacturing
methods. Because of the Computer Numerical Control (CNC) machines used in production
and the part programs being made by the stored geometry from the design stage, the scrap
level would be reduced to the minimum possible and almost no rework would be necessary.
Since all the information and controlling functions are attempted with the help of the computer,
a better management control on the manufacturing activity is possible. All the above advantages
when properly translated, would mean a lower total cost and consequently, higher final
earnings. Therefore any manufacturing activity in a production unit (job shop production or
mass scale manufacture) can get the benefits of Computer Aided Manufacturing. However,
better results can be obtained when the design and manufacturing activities are properly
integrated. Also, when there is a large variety of products or minor changes required in the
existing production programme, CAM can easily manage the necessary changes or alterations.
Following are the main advantages of using CAM.
1. Greater design freedom
Any changes that are required in design can be incorporated at any design stage without
worrying about any delays, since there would hardly be any in an integrated CAM environment.
2. Increased productivity
In view of the fact that the total manufacturing activity is completely organized through
the computer, it would be possible to increase the productivity of the plant.
3. Greater operating flexibility
CAM enhances the flexibility in manufacturing methods and changing of product lines.
4. Shorter lead time
Lead times in manufacturing would be greatly reduced.
The integration of CAD and CAM systems is called Computer Integrated Manufacturing
(CIM) system. The role of computer in manufacturing may be in two major groups namely
computer monitoring and control of the manufacturing process and manufacturing support
applications, which deal essentially with the preparations for act of manufacturing and post
manufacture operations. Computers are used in controlling machine tools and other material
handling equipments.
10 Introduction to Basic Manufacturing Processes and Workshop Technology
1.12 KINDS OF PRODUCTION SYSTEMS
The choice of production type dictates the machine requirements, organizational system to
a large extent, layout planning and inventory subsystems. Three main types of production are
job, batch and flow or process production. The simplest way is to classify based on production
and processes by lot size, namely single unit production, small lot production, moderate lot
production, large lot production, and continuous production. The second classification comprises
three categories, namely small size production of a large variety of products, medium-scale
production of a limited range of products, and a large-scale production of a small variety of
products. Obviously, this method is related to the number of product types and production lot
sizes, and is an effective means of analyzing modern production management. The third
classification is related to the size of the production system expressed through the number
of employees or the amount of fixed assets involved, namely small production unit employing
less than 30 employees, medium-small having 30 to 300 employees, medium with 301 to 2,000
employees and large with 2001 to 15,000 employees, and a giant corporation employing more
than 15,000 employees
Job shop production deals the manufacture of very small lots, often of single jobs. This
may be required in special situations for the purpose of proving a design, making prototypes,
in tool making or for special purpose applications. In view of the very small lot, no special
purpose machines or tooling can be economically justified. Hence, the manufacturing has to
be carried on with the general purpose machines and tooling, which is a very lengthy and
often an error prone process.
SUGAR MANUFACTURING PROCESS
1.13 MANUFACTURING SYSTEM
Manufacturing basically implies making of goods or articles and providing services to meet
the needs of mankind. It creates value by useful application of physical and mental-labor in
the process. It is a chain of interrelated activities of production process and other support
services activities of an manufacturing environment such as order processing, product design,
design and manufacturing of tools, die, mould, jigs, fixtures and gauges, selection of material,
planning, managing and maintaining control of the processes, production, and reliable quality
of processed product in a systematic and sequential manner with proper coordination,
cooperation and integration of the whole manufacturing system that will lead to economical
production and effective marketing of proposed product in the minimum possible time. It is,
therefore, evident that manufacturing today is not a one man activity as it was in the initial
stages, wherein all the physical and mental inputs were applied by a single craftsman. These
days it has become totally a team work which consists of several components interacting
together in a dynamic manner. This entire domain of manufacturing is known as Manufacturing
System, which takes the required inputs and delivers the products for the customer. It is,
therefore, evident that manufacturing today is not a one man activity as it was in the
preliminary stages, wherein all the physical and mental inputs were provided by a single
workman. Today it is a team work which consists of several components interacting together
in a dynamic manner to provide the required physical and mental inputs at appropriate stages
to impart desired results. This entire domain of manufacturing is known as Manufacturing
System, which takes the required inputs and delivers the products for the customer.
Manufacturing system requires a large number of activities, few independent and rests
mostly interrelated. The manufacturing activities in a manufacturing system jointly contribute
towards economic and qualitatively acceptable production of desired articles in minimum
possible time. As per the need of the customer, the products are identified and their demands
are determined roughly for market forecast by considering present and future competition.
Products that may render the desired service over its expected life satisfactorily as per
requirement of customers are identified in terms of their demand, conceived and developed
for securing orders by the sales department. Once the product design activity is over and the
design finalized from all angles, functional, aesthetic, material selection, safety, economy, etc.,
it is followed by preparation of production drawings of the product assembly and its components
including a bill of materials. This is the stage where a make or buy decision has to be taken
in order to decide as to which components are to be bought from outside and which are to
be manufactured within the concern. It is followed by process planning i.e. selection of the
best process and an its parameters, design of jigs, fixtures and dies, selection of tooling,
programming of tool path as per need, for the components to be produced in-house. An
important activity in process planning within the organization is also to involve latest research
and development findings, through which the old processes are improved and new one’s are
developed in order to ensure better quality and economic production. The interaction of
different manufacturing activities in a manufacturing system can also be further enhanced by
the use of computer and hence leading CIM. The real manufacturing or production activity
is carried out on the shop. The layout of the shop floor has a significant influence on the tools
required to be coordinated in order to an economical and high quality production of various
components. It should be such that it ensures timely movement of raw materials, dies
moulds, jigs and fixtures and finished components, adequate safety to men, material and
machinery, enables timely inspection and quality control and minimizes handling time for
material and parts, etc. During actual manufacturing a lot of different activities are called
management function. Various engineers play an important role in the organizational function
of a manufacturing concern. They are required to ensure proper movement of the material,
tools and parts as per their specialized jobs in industry.
1.14 PRODUCT DEVELOPMENT
A product development has to go through the following concepts of product engineering which
are given as under.
Product functions
1. Product specifications
2. Conceptual design
3. Ergonomics and aesthetics
4. Standards
5. Detailed design
6. Prototype development
7. Testing
8. Simulation
9. Design for manufacture
10. Design for assembly
11. Drafting.
Now let us consider the manufacturing environment of a given product. How does the
product idea originate. Market forces determine the need for a product. Expertise on the part
12 Introduction to Basic Manufacturing Processes and Workshop Technology
of the company estimates the likely demand and probable profitability and decides on the best
mode of designing and manufacturing the desired product.
Traditionally, after the design of the product, the part prints are released for production.
The production engineering section first considers the feasibility of production of the product.
Having ascertained its feasibility, process planning is done so that the product can be
manufactured at the lowest possible cost. Any redesign that is needed for improving the
producibility of the product without compromising on its functionality would have to be done
at this stage. Having decided on the process plan for manufacture, the necessary actions are
undertaken for its implementation. These are making of the tooling required, acquiring of
new equipment or tools, procurement of the raw materials, releasing of the detailed operational
instructions to the shop floor, etc. The conventional methods of manufacturing are generally
inefficient and dependent on operator skills. These methods consume more time, have high
costs, and give poor accuracy.
Product design is an activity which needs to be well organized and take into account all
influences that are likely to be responsible for the success of the product under development.
A product here means a single component which is functional in itself like a wrench or an
assembly of a large number of components all of which will contribute to the functioning of
the part such as an automobile engine. The complexity of the design process certainly increases
with the number and diversity of components present in the final part. Since there are such
a large number of influencing factors, it is impossible to specify a design procedure for each
component. Here we are interested in developing some common guidelines and steps that are
needed to proceed for a successful product design and manufacture.
From the above discussion it can inferred that products can be manufactured by more
than one processes. Therefore several alternatives for manufacturing products are available.
The selection of a suitable process is depended upon the factors including volume of production,
properties of the components, technical viability of process, economy involved and desired
quality. Based upon the volume of product the manufacturing activity can be identified in
terms of job shop production, batch production and mass production
1.15 COMPUTERS IN MANUFACTURING INDUSTRIES
Factors governing increased productivity, more accuracy, greater flexibility of shapes, and
reduced manufacturing costs are forcing the manufacturing concerns to use computers in
design, manufacturing and other allied functions of industrial activities. With an increase in
the need for quality manufacturing along with the factors such as short lead time and short
product lives and increasing consumer awareness as regards the quality of the product, it is
becoming increasingly important for the manufacturers to initiate steps to achieve all these.
The developments in microelectronics in the recent past have made higher computational
ability available at a low cost. Therefore, it becomes imperative that manufacturing takes
advantage of the availability of low cost and also using yet more powerful computers. Computers
have been in use in manufacturing industries since 1960. Initially they were in use only in
supportive functions such as inventory control purchase accounting, etc. In to day’s time,
computer applications have progressed considerably in all areas of design and manufacturing
involving CAD and CAM. This however needs to be emphasized that all the benefits of CAD
and CAM can be achieved only if these two important functions are effectively interfaced. This
interfacing is known as CAD/CAM. It involves the flow of information in both the directions.
With the result the parts and assemblies are designed keeping in view the limitations and
capabilities of the processes and materials. Consequently, newer and superior products can be
produced more quickly and at lower costs.
Today, computers are not only used in manufacturing but they play also an important
role in all manufacturing related activities such as business or financial management, factory
level production management, CIM technologies, CAD, feature and solid modelling, and
CAM, manufacturing information, manufacturing system. The important sub-activities of
industrial environment have been identified to support with the use of computer in the
manufacturing industries.
These are given as under:
1. Business or Financial Management
1. Costing
2. Sales and Marketing
3. Purchase Order Control
4. Vendors
5. Subcontracting
6. Personnel.
2. Factory Level Production management
1. Planning
2. Production Management
3. Manufacturing production scheduling (MPS)
4. Material requirement planning (MRP)
5. Just in time (JIT)
6. Bill of Materials
7. Capacity Planning
8. Inventory Control.
3. CIM Technologies
1. Computer Networks
2. System Design and Analysis
3. Distributed Processing
4. Database Management Manufacturing
5. Modelling and Simulation
6. Expert Systems
7. Quality Engineering.
4. Computer Aided Design (CAD)
This area is also known Feature and Solid Modelling
1. Variational and Parametric
2. Modelling
3. Computer Graphics
4. Graphic Standards
14 Introduction to Basic Manufacturing Processes and Workshop Technology
5. Inter-graphics exchange specification (IGES)
6. Data exchange file (DXF)
7. Manufacturing Robot Programming
8. Design Analyses Tools
9. Programming
10. Finite element modelling (FEM)
11. Finite element analysis (FEA)
12. Simulation
13. Mechanisms
14. Test and Analysis
15. Design Tools Mechanical
16. Hydraulic, Electronics, etc.
5. Computer Aided Manufacturing (CAM)
This involves activities related to manufacturing information and manufacturing system
which are given as under—
Manufacturing Information
1. Generation
2. Process Planning
3. Production Planning
4. Computer numerical control (CNC) part Programming
5. Robot Programming
6. Coordinate measuring machine (CMM) Programming.
Manufacturing System
1. Production Activity
2. Machining
3. Assembly
4. Material Handling
5. Storage
6. Production Control
7. Loading
8. Scheduling
9. Balancing
10. Capacity Planning
11. Quality Control.
One of the most important components for getting various benefits associated with
computer applications in manufacturing is the common databases associated with all aspects
of manufacturing. In fact, all the modules in the CAM would actually be sharing the database
created in any module. Any module would be able to modify the data as required for that
particular application. This approach reduces the work involved in maintaining the product
database and at the same time includes the latest modifications for any aspect related to
manufacturing. In contrast to the common database approach, it is possible that sometimes
individual modules in the production aspects may be taken from different vendors. In this
case care need to be taken that information is properly transmitted between the modules and
the data updating in all the modules takes place properly and at the right time. Some of above
mentioned manufacturing activities are controlled by computers. These activities are commonly
identified using the following terms.
1. Computer Aided Design (CAD)
2. Computer Aided Engineering (CAE)
3. Computer Aided Design And Drafting (CADD)
4. Computer Aided Process Planning (CAPP)
5. Computer Aided Tool Design (CATD)
6. Computer Aided Manufacturing (CAM)
7. Computer Aided Numerical Control (NC) Part Programming
8. Computer Aided Scheduling
9. Computer Aided Material Requirement Planning, etc.
10. Flexible Manufacturing System (FMS)
11. Group Technology (GT)
12. Computer aided Testing (CAT).
1.16 QUESTIONS
1. How do you classify the manufacturing processes?
2. Distinguish between ‘primary’ and ‘secondary’ processes?
3. Discuss primary shaping processes. Give also a brief account of the primary shaping processes.
4. Explain the secondary or machining processes. Give also a brief account of these processes.
5. Describe and name the types of joining processes, surface finishing operations and the
processes employed for changing the properties of manufactured components.
6. Write a short note on assembly process.
7. Write short notes on:
(a) Simplification, (b) Standardization, (c) Inspection and quality control, (d) Interchangeability,
(e) Mechanization, (f) Automation, (g) Mechatronics.
8. What do you understand from the terms Manufacturing, Process plan, Maintenance?
9. Explain the term ‘Manufacturing System’. What all it encompasses and how an integrated
approach is made for making an economical and competitive product? Describe how the use
of computers helps in increasing manufacturing efficiency.
10. Explain the terms CAD, CAM, NC, CAD/CAM, MRP, FMS and CIM?
11. Write a short note on Group Technology?
12. Explain the influence exerted by the computers on the manufacturing scene?
13. Briefly explain the conventional process of the product cycle in the conventional manufacturing
environment.
16 Introduction to Basic Manufacturing Processes and Workshop Technology
14. What are the functions that get benefited by the use of computers in design and manufacturing
functions?
15. Briefly explain the various automation aspects used in manufacturing activities.
16. Write down the advantages which can be gained by the adoption of CAD?
17. Describe the advantages which can be gained by the adoption of CAM?
18. Write down the advantages which can be gained by the adoption of FMS?
19. Write down the advantages which can be gained by the adoption of manufacturing production
scheduling (MPS)?
20. Write down the advantages which can be gained by the adoption of Material Requirement
Planning (MRP)?
21. Explain the main advantages which can be gained by the adoption of CIM
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Basic Manufacturing Process
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