The document discusses various manufacturing processes and considerations for component design based on the selected process. It describes primary, secondary and tertiary manufacturing processes and provides details on casting, forging and sheet metal processes. Key factors for casting include part complexity, material properties and economics of production quantities. For forging, important considerations include parting lines, draft angles, fillets and corners to enable uniform metal flow. Sheet metal design must account for material thickness and formability limitations.

1. SUBMITTED BY:-
VARUN (162220)
CHANDANMATTU(152205)

2.  The goal of this seminar is to illustrate how the
manufacturing processes influence the design of
components, with emphasis on the following:-
 Types of available manufacturing process and their
selection.
 Design considerations for cast components.
 Design considerations for forged components
 Design considerations for sheet metal components

3. Many processes form a natural sequence for shape
generation. For example, casting and forging are
normally followed by machining then surface finishing
if needed, Processes can be grouped as follows:
a)Primary processes:- Casting, bulk forming (forging,
rolling, extrusion), etc.
b)Secondary processes:-Joining and welding, sheet-metal
work, heat treatment, metal cutting, etc.
c)Tertiary processes or finishing processes:-Surface
treatment, grinding, coating, etc.

4. PRIMARY PROCESSES
SECONDARY PROCESSES
TERTIARY PROCESSES

6.  Not all processes are suitable for all materials.
 For example cast iron cannot be forged.
 Powder metallurgy is uneconomical for a limited
production run.

7.  Casting is a manufacturing process in which a liquid
material is usually poured into a mold which contains a
hollow cavity of the desired shape, and then allowed to
solidify. The solidified part is also known as a casting,
which is ejected or broken out of the mold to complete
the process.
 Casting is most often used for making complex shapes
that would be otherwise difficult or uneconomical to
make by other methods

8. In such cases, the following factors should be considered:
1. Casting is particularly suited for parts which contains
internal cavities that are inaccessible, too complex, or too
large to be easily produced by machining.
2. It is advantageous to cast complex parts when required in
large numbers, especially if they are to be made of
aluminum or zinc alloys.
3. Casting techniques can be used to produce a part which is
one of a kind in a variety of materials, especially when it is
not feasible to make it by machining.
4. Precious metals are usually shaped by casting, since there
is little or no loss of material.
5. Parts produced by casting are isotropic, which could be an
important requirement in some applications

9. 6. Casting is not competitive when the parts can be
produced by punching from sheet or by deep
drawing.
7. Casting is not usually a viable solution when the
material is not easily melted, as in the case of metals
with very high melting point such as tungsten.

10. It is important for designer to observe some general rules which
are related to :
1.Solidification of metal 4.Allowances given
2.Gating system 5.Riser design
3. Material of casting

11.  A general rule of solidification is that the shape of the casting
should allow the solidification front to moves uniformly from
one end toward the feeding end, i.e. directional solidification.
 This can most easily be achieved when the casting has
virtually uniform thickness in all sections.
 When section thickness must change, such changes should be
gradual, in order to avoid feeding and shrinkage problems.
 Sudden changes in section thickness give rise to stress
concentration and possible hot tears in the castings.
 Another problem which arises in solidification is caused by
sharp corners, as these also give rise to stress concentration
and should be replaced by larger radii.

13.  When two sections cross or join, the solidification process is
interrupted and a hot spot results.
 Hot spots retard solidification and usually cause porosity and
shrinkage cavities.
 Cavities at hot spots can be eliminated by using small cores. It is
important to maintain (as much as possible) uniform cross sections
and wall thicknesses throughout the casting to avoid or minimize
shrinkage cavities.
 Metal chills in the mold can eliminate or minimize hot spots.
 Large unsupported flat areas should also be avoided as they tend to
warp during cooling.

16.  Shrinkage allowance
 Machining allowance
 Draft allowance
 Distortion allowance
 Shake allowance

17. 1. Shrinkage allowances : This type of allowances is provided on
the pattern. During solidification molten metal gets shrink. To
compensate it shrinkage allowance is provided over the pattern.
2. Machining allowances : A cast surface is too rough to used as
final product, so we required some machining on it to get finish
product with good surface. For which machining allowances are
provided.
3. Draft allowances: It is provided for easy removal of pattern
from the mould .
4. Distortion allowances: Casted part some time gets distorted
after solidification , this is happens in thin sections , I-sections,
U-sections. To minimize it distortion allowances given.
5. Shake allowances : when the pattern is to be remove from his
place to make cavity , some shaking action has to be done. To
compensate that changes in dimensions we provide shake
allowances.

19.  Gating system refers to all those parts which comes in path of
flow of molten metal from ladle to mould cavity.
 Good gating design ensures distribution of the metal in the mould
cavity at a proper rate without excessive temperature loss,
turbulence and entrapping gases and slag's.
 If the liquid metal is poured very slowly, then the time taken to
fill up the mould is rather long and the solidification may start
even before the mould has been completely filled up.
 This can be avoided by increasing the superheat of molten
metal.
 On the other hand if the liquid metal impinges on the mould
cavity with too high velocity, the mould surface may be eroded.
 So, a compromise has to be made in arriving at an optimum
velocity.

21.  Parting Plane
 A parting plane is the plane at which the two die halves of the
forging meet. It could be a simple plane or irregularly bent,
depending on the shape of the forging.
 The parting plane should be the largest cross sectional area of
the forging, since it is easier to spread the metal than to
force into deep pockets.
 It may be required to put more metal into the top die half since
metal would flow more easily in top half.

22. It is the taper put on all the forging sides arranged
parallel to the travel of the press slide or hammer ram.
This makes it easier for the metal to fill up the working
volume of the die impressions and facilitates the
removal of the forging.
Recommendation:-
Draft
7 degree exterior draft angle and 10 degree interior draft
angle

23.  Since forging involves flow of metal in orderly
manner, therefore it is necessary to provide a
streamlined path for the flow of metal so that defects
free forging is produced.
 When two or more surfaces meet, a corner is formed
which restricts the flow of metal. These corners are
rounded off to improve the flow of metal.
 Fillets are for rounding off the internal angles,
whereas corner is that of the external angle.

25.  Let us consider the flow of metal over a corner as shown in the
figure a. Because of large corner radius provided, metal is
allowed to flow smoothly into the pocket.
 But when corner radius is small or not provided as in figure b,
the metal flow is first hindered and when it finally enters the
cavity, the metal would fold back against itself forming a
defect called lap or cold shut

26.  Shrinkage allowances: The forgings are generally made
at a high temperature of 1150 to 1300o C. At this
temperature, the material gets expanded and when it is
cooled to the atmospheric temperature, its dimensions
would be reduced. Hence a shrinkage allowance is
added on all the linear dimensions.
 Die wear allowances
 Machining allowances

27.  It is obvious that the die is one of the most critical
components of the forging operations, and therefore
the process depends considerably on the design of die.
 To ease the flow of metal around the corners, a proper
fillet radius should always be provided. This is helps
in preventing excessive die wear and fracture of
metals near the corners.
 A space around die edges should be provided to
accommodate the excess material, known as flash .
 To receive this flash, it is recommended that a flash
gutter be provided.

28.  Generally, sheet metal parts are produced by shearing ,
bending and/or drawing .
 Quality of sheet metal play an important role
determining the quality if the finished product .
 Another factor important in sheet metal design is
formability of sheet.

29. 1. Diameters of punched holes should be more than sheet
thickness with minimum of about 0.6mm.
2. Small holes result in extensive punch breakage and should
be drilled.
3. The distance between holes, or between a hole and sheet
edge, should be at least equal to sheet thickness.
4. The width of any slot should be at least 1.5 times the sheet
thickness with a minimum of 3mm.
5. It may be less expensive to design the component from
several simple parts than to make an intricate blanked part.
6. Blanks with sharp corners are more expensive to produce.

30. 7 Most important factor which should be considered when
designing parts that are to be made by bending is bend
ability.
8 Another factor which should be considered when designing
for bending is spring back which is caused by the elastic
recovery of the material when the bending forces are
removed.
9. One way of compensating for spring back is to over bend
the sheet.

31. 1.Farag Mohmoud M., “Selection of Materials and
Manufacturing Processes for Engineering Design”, Prentice
Hall, New York, 1st Edition, 1989.
2.Dieter George E., “Engineering Design: A Material and
Processing Approach”, McGraw Hill, 2000.
3.“Introduction to Manufacturing Processes” by Schey J
4.“Materials and Processes in Manufacturing” by DeGarmo E.
P., Black J. T. and Kohser R. A
5. “Manufacturing Process for Engineering Materials” by
Kalpakjain