1. Wollo University
Institution of Technology
College Of Engineering
Department Of Mechanical Engineering
Course Title: Manufacturing process one(I)
Course Number: IEng2100
Ects’5: 2 Lectures. 3 Lab
Target group :- Industrial Engineering 2nd year
Instructor Name; Ahmed D. (MSc in Manufacturing Engineering)
2. Chapter one
Contents to be discussed
Introduction on Manufacturing process
Production Process Vs. Manufacturing Process
Classification of manufacturing process
Selection of manufacturing process
3. Introduction on Manufacturing Process
What is manufacturing?
Literal:- Manufacture = Manus (hand) + Factus (make)
Made by hand
Technological:-Application of physical and chemical processes to make parts
or products, including assembly of products.
CIRP definition:-Design + production + assembly
• (CIRP = International Academy for Production Eng.)
As per oxford English dictionary manufacture refers “to make or
produce goods in large quantities, using machinery”.
4. 1.2 Working definition of manufacturing
There are two types of working definitions available for manufacturing:
technical process and as an economic process.
Technologically: Manufacturing is the application of physical and
chemical processes to alter the geometry, properties and or appearance of
a given starting material to make parts or product as shown in Figure 1.1
Fig 1.1 Definition of manufacturing in terms
5. Economically: Manufacturing is the transformation of materials
into items of greater value by means of one or more process and or
assembly operation as shown in Figure 1.2
Fig 1.2 Definition of manufacturing in terms of economic value
6. 1.3 PRODUCTION PROCESS Vs. MANUFACTURING PROCESS
PRODUCTION PROCESS: The art of converting raw material into finished
goods with application of different types of tools, equipment's, machine
tools, manufacturing set ups and manufacturing processes, is known as
MANUFACTURING PROCESS:- part of the production process which is
directly concerned with the change of form or dimensions of the part being
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
7. 1.4 Classification of manufacturing processes
Manufacturing processes can be classified as
In processing operation the work material is transformed from one
state to other advanced state.
Through this operation value is added to the work material by
changing the geometry; shape properties, appearance etc. of the
starting work material.
Usually processing operations are performed on individual
component. But in some cases like aerospace industry, the
processing operations are performed on assembled items also.
8. In assembly operation two or more components are joined to
create a new entity.
The new entity is called assembly, subassembly based on its state in the
If the entity is an intermediate state of the product, it is called
subassembly. Some other terms are also referred based on the joining
The assembly created by welding operation is called weld met.
10. 1.5 Basic Manufacturing Processes
The basic manufacturing processes can be classified as:
Casting, foundry, or molding processes
Forming or metalworking processes
Machining (material removal) processes
Joining and assembly
Surface treatments (finishing)
11. Casting: the metal is heated sufficiently to make it into liquid and then
poured into moulds of desired shapes. They can be expendable mold and
Forming and Shaping: Large group of manufacturing processes in which
plastic deformation is used to change the shape of metal work pieces .
Some processes are rolling, forging, extrusion, drawing, sheet forming,
12. Machining: The process of removing the undesired or unwanted
material from the work piece or job or component to produce a required
shape using a cutting . Some machining operations are turning, boring,
drilling, milling, planning, shaping, broaching, grinding, ultrasonic
machining, chemical machining, electrical discharge machining (EDM),
electrochemical machining, high-energy beam machining e.t.c
Joining: widely used in fabrication and assembly work. For which two
or more pieces of metal parts are joined together to produce desired
shape and size of the product. Some of the important and common
joining processes are welding, brazing, soldering, diffusion bonding,
adhesive bonding, mechanical joining
13. Surface Finishing(surface treatment): 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; either a very negligible amount of material is removed from
the certain material is added to the surface of the job e.g honing,
lapping, polishing, burnishing, deburring, surface treating, coating,
Heat treating is can be carried out to enhance various properties , affect
the physical properties and also make a marked change in the internal
structure of the metal. e.g Annealing, Normalizing, Case-hardening
14. 1.6 Selection of manufacturing process
There are hundreds of manufacturing processes. You are likely to
already be familiar with the most common, e.g. casting, forming,
molding and machining.
For any given product, there will be multiple manufacturing
processes that you’ll need to select from.
The process you choose will depend on many factors called the
process selection drivers.
15. •These process selection drivers include the following:
•Quantity of the product
•Cost for tooling, manufacturing machines and equipment
•Time required for processing
•Level of skilled labor required
•Availability of material and cost of material
•Capabilities required to processes material
16. •Product dimensions and size
•Surface finish required
•Waste produced by the process
Figure 1.4 schematically outlines the steps to select a suitable
manufacturing process for a given part provided the material and
the shape of the part are finalized.
The manufacturing requirements are expressed as constraints on
material, shape, size, tolerance, roughness, and other process
17. The constraints are used to screen out processes that are
incapable of meeting them, using process selection diagrams.
The surviving processes are then ranked according to
economic measures and then the top ranked candidates are
explored for supporting information to be enabled as final
19. 1.6.1 Selection charts
Process-Material matrix:-indicating the general compatibility
between manufacturing process and engineering material.
The processes are also broadly classified as shaping, joining and
The dot indicates that the pair of the material and the process is
compatible. For example, sand casting or die casting process cannot
be used for processing of composite materials.
Thus, an initial screening of processes for a given material can be
easily performed based Figure 1.5
21. Process-Shape matrix:- Various manufacturing processes are
capable of making these shapes. For example, a typical turning
operation creates axisymmetric shapes while extrusion, drawing
and rolling make prismatic shapes – both circular and non-circular
23. Process-Mass bar-chart:- Large components can be built up by
joining smaller ones, It can be noted that sand casting
process, for example, is capable of producing large
component while die
casting or investment casting processes can make
relatively smaller sized parts.
24. Figure 1.7 Process–Mass bar chart indicating compatibility between t
requisite mass of a part and the corresponding manufacturing proces
25. Process-Section thickness bar-chart: The selection of a
manufacturing process also depends on the section thickness of the
part to be made.
Each process has its limit over the range of the section thickness,
which it can produce. For example, surface tension and the typical
nature of heat flow limit the minimum section and slenderness of
gravity-die cast shapes.
Bulk deformation processes cover a wider range of section
thickness. Limits on forging pressures also set a lower limit on the
section thickness and slenderness that can be forged.
Powder forming methods are more limited in the section
thicknesses they can create, but they can be used for ceramics and
very hard metals that cannot be shaped in other ways.
Special techniques such as electro-forming, plasma spraying allow
manufacturing of slender shapes.
26. Figure 1.8 Process–Section thickness bar chart indicating compatibility between
the manufacturing process and the range of section thickness that each process
can produce 
27. Process – Dimensional Tolerance bar-charts: Tolerance and
surface roughness that a specific manufacturing process can provide
is an important characteristic.
Manufacturing processes vary in the levels of tolerance and
roughness they can achieve economically. For example, die casting
process with the permanent metallic dies can give
better surface finish compared to the same achievable in sand
Machining is capable of delivering high dimensional accuracy and
surface finish when the process parameters are controlled properly.
Grinding can be adopted to achieve very high tolerance while such
precision and finishing operations are generally expensive.
28. Figure 1.9 Process – Tolerance Limit bar chart indicating compatibility between
the manufacturing process and tolerance limit 
29. Figure 1.91 Process – Surface roughness Limit bar chart indicating compatibility between
the manufacturing process and minimum surface roughness limit [2
30. Following are some generic steps which are often followed in
the selection of manufacturing process such as:
• keep things standard
• keep things simple
design the parts so that they are easy to assemble
• do not specify more performance than is needed
31. How to use the process selection charts?
The charts described above provide a quick overview and
comparison of the capabilities of various manufacturing processes.
However, these charts must be used sufficiently carefully for a
given shape, material, dimension, requisite tolerances and surface
roughness considering the both the capabilities and limitations of
Often, the major cost associated with a given part lies from the
wrong choice of manufacturing process(es).
32. Economic criteria for selection
The choice of the process also depends on the batch size that is
required to produce. Often manual processing is suitable when the
quantity to be produced is low. However, the cost to manufacture
increases with the increase in batch size e.g. the manual cost that
warrants automated manufacturing process for medium to large
Figure 3.8.9 typically represents the broad relation between various
manufacturing processes and the corresponding economic batch
33. Figure 1.92 Schematic Process vis-à-vis Economic Batch Size (in units) of various
manufacturing processes