This PPT is useful for First Year of Engineering Students and faculties as well as Mechanical Engineering Students.

2. CONTENTS
• CASTING
• FORGING
• SHEET METAL WORKING
• METAL JOINING PROCESS

4. Introduction to manufacturing
process
• It is process of converting the raw material
into finished product using machines.
Raw materials
Manufacturing
process
Finished
product

5. Classification of Manufacturing
process
MANUFACTURING
PROCESS
CASTI
NG
METAL
FORMI
NG OR
DEFOR
MING
MACHI
NING
SURFA
CE
FINISH
ING
POWD
ER
METAL
LURGY
SHEET
METAL
WORKI
NG
METAL
JOININ
G PROCESS
EFFECTING
CHANGE
OF
PROPERTIE
S

6. Casting
Process in which molten metal flows by gravity
or other force into a mold where it solidifies
in the shape of the mold cavity
• The term casting also applies to the part
made in the process
• Steps in casting seem simple:
1. Melt the metal
2. Pour it into a mold
3. Let it freeze

7. Advantages of Casting
• It can create complex part geometries which is
difficult to produce by other Manufacturing
process
• It can create both external and internal shapes
• It can produce very large parts, there is no
restriction on the size of the component
• Some casting methods are suited to mass
production
• Cost of the component is very low
• No restriction on type of metal or alloy used

8. Disadvantages of Casting
• The component less than 6mm thickness can’t be
produce by this process
• It is high energy consuming process
• Large space is required (working area, furnace, raw
material etc.)
• Limitations on mechanical properties because blow
hole, gas cavities and non metalic incursion reduces
the strength
• Poor dimensional accuracy and surface finish for some
processes; e.g., sand casting
• Safety hazards to workers due to hot molten metals
• Environmental problems

9. APPLICATIONS OF CASTING PROCESS
• Typical applications of sand casting are:
• Cylinder Liners
• Pistons
• Machine tool beds
• Piston Rings
• Water supply pipes
• Bells
• Mill rolls etc.

10. Casted Products

11. Terminology in Casting Process
Two forms of mold: (a) open mold, simply a container in the shape of
the desired part; and (b) closed mold, in which the mold geometry is
more complex and requires a gating system (passageway) leading
into the cavity

12. Flask
The box containing the mold
Cope
The top half of any part of a 2-part mold
Drag
The bottom half of any part of a 2-part mold
Core
A shape inserted into the mold to form
internal cavities
Core Print
A region used to support the core

13. Mold Cavity
The hollow mold area in which metal solidifies
into the part
Riser
An extra cavity to store additional metal to
prevent shrinkage
Gating System
Channels used to deliver metal into the mold
cavity
Pouring Cup
The part of the gating system that receives
poured metal
Sprue
Vertical channel
Runners
Horizontal channels

14. Parting Line / Parting Surface
Interface that separates the cope and drag of a 2-
part mold
Draft
Taper on a pattern or casting that allows removal
from the mold
Core Box
Mold or die used to produce cores
Casting
The process and product of solidifying metal in a
mold

15. Casting
processes
Special
casting
process
Plaster(cera
mic) mould
casting
process
Permanent
mould
casting
process
Die casting
process
Shell mould
casting
process
Centrifugal
casting
process
Continuous
casting
process
Sand casting
process
Types of casting process

16. Sand casting process
Steps in Sand casting process:
1. Pattern making
2. Mould making
3. Core making
4. Melting and pouring of metal
5. Cooling and solidification of casting
6. Cleaning and inspection of casting

17. Advantages of sand casting Process
• Highly Economical
• Does not require high initial investment
• Suitable for small quantity job production as
well as mass production

18. Disadvantages of sand casting Process
• Poor dimensional accuracy as well as poor
surface finish hence not suitable for making
precision casting
• Not suitable for producing highly intricate
shapes
• Can’t produce extremely thin section
• It requires large working space
• This process requires large man power
because each casting requires one mould

19. Core
Full-scale model of interior surfaces of part
• It is inserted into the mold cavity prior to
pouring
• The molten metal flows and solidifies between
the mold cavity and the core to form the
casting's external and internal surfaces
• May require supports to hold it in position in
the mold cavity during pouring, called
chaplets

20. Figure 11.4 - Core held in place in the mold
cavity by chaplets
(b) possible chaplet design
(c) casting with internal cavity

22. Desirable Mold Properties and
Characteristics
• Strength - to maintain shape and resist erosion
• Permeability - to allow hot air and gases to pass
through voids in sand
• Thermal stability - to resist cracking on contact
with molten metal
• Collapsibility - ability to give way and allow
casting to shrink without cracking the casting
• Reusability - sand from broken mold can be
reused to make other molds

23. Foundry Sands
Silica (SiO2) or silica mixed with other
minerals
• Good refractory properties - capacity to
endure high temperatures
• Small grain size yields better surface
finish on the cast part
• Large grain size is more permeable, to
allow escape of gases during pouring
• Irregular grain shapes tend to strengthen
molds due to interlocking, compared to
round grains
– Disadvantage: interlocking tends to reduce
permeability

24. Binders Used with Foundry Sands
• Sand is held together by a mixture of water and
bonding clay
– Typical mix: 90% sand, 3% water, and 7% clay
• Other bonding agents also used in sand molds:
– Organic resins (e g , phenolic resins)
– Inorganic binders (e g , sodium silicate and phosphate)
• Additives are sometimes combined with the
mixture to enhance strength and/or permeability

25. Types of Sand Mold
• Green-sand molds - mixture of sand, clay, and
water;
– “Green" means mold contains moisture at time of
pouring
• Dry-sand mold - organic binders rather than
clay and mold is baked to improve strength
• Skin-dried mold - drying mold cavity surface of
a green-sand mold to a depth of 10 to 25 mm,
using torches or heating lamps

26. Casting Defects
A. Metallic Projections
B. Cavities
C. Discontinuities
D. Defective surface
E. Incomplete Casting
F. Incorrect dimensions or shape
G. Inclusions (different composition)

27. Blow holes
axial shrinkage
shrinkage

29. Casting Defects
Porosity may be caused by shrinkage and/or gases
Thin sections solidify faster than thick sections;
therefore the molten metal cannot be supplied to
thick regions that are solidifying
Gases become less soluble in a metal as it cools and
solidifies, causing it to be expelled and sometimes
form or expand porosity

31. It is the process in which the component of
desired shape and size is obtained through the plastic
deformation of the metal or alloy under the action of
externally applied force.
It can be carried out on the metal in either hot or cold
condition.
The various metal forming processes are:
The external force on the metal during the metal forming may
be tensile force, compressive force, shear force or a
combination of these forces.
Forging
Rolling Wire Drawing Bending
Deep drawingExtrusion

32. Forging is a metal forming process in which the metal or alloy
is first heated and then plastically deformed to the desired size
and shape by the application of compressive force using a hand
hammer, a power hammer, or a press.
The material is heated to a temperature at which its elastic
properties completely disappear. This temperature is known
as forging temperature and it varies from material to material.
At forging temperature, the material becomes soft and obeys
the law of plastic flow. It thus deforms plastically in the
direction of least resistance without fracture.
Early applications include: swords, knives, arrows, protective
armour, helmets, etc.

33. The material is deformed into the desired
shape between two parts called dies. The
shape of the die matches with the shape
of desired component.
The forging press consist of lower die
fixed to the frame while upper die is
connected to ram.
The hot material is kept on the lower die.
During the downward stroke of the ram,
the upper die exerts the sudden
compressive force on the hot material and
is converted into desired shape.
The press operates at about 30 - 60 strokes/min.

34. The material used for forging should be ductile as ductility
enables the material to deform plastically without fracture.
Common examples are: Low & medium carbon steel, alloy steel,
stainless steels, copper alloys, aluminium alloys, etc.
High dimensional accuracy & surface finish. Hence it reduces
the material removal during the machining & finishing
operations.
Forging reduces grain size which results in improving strength
and toughness.
Forged products have high strength to weight ratio.

35. Brittle materials like cast iron cannot be forged.
Cannot produce complex intricate shape like casting process.
Cost of forged components is more than casted components.
Cost of forging dies is high.
IC engine parts like crankshaft, connecting rods, rocker arm, etc.
Small tools like spanners, etc.
Levers,
Automobile and aircraft components.
It produces component without shrinkage cavities, blow holes
and machining scratches, which increases the endurance
strength.

36. APPLICATIONS OF FORGING

37. APPLICATIONS OF FORGING

39. Definition: It is deformation of material into predetermined shape is carried
out at temperature greater than its recrestallization temperature.
The hot forging manufacturing process is performed at extreme high
temperature (up to 1150 °C for steel, 360 to 520 °C for al-alloys, 700 to 800 °C
for cu-alloys). Stamping is the most widespread hot forging manufacturing
process, where the material is squeezed in a press, between a tool and a die
surface.
Hot Forging Manufacturing Process
Advantages of Hot Forging
• Hot forged components possess increased ductility. Also, as a technique hot
forging is more flexible than cold forging,
• The excellent surface quality allows a wide range of finishing work as polishing,
coating or painting.
• Yield strength of the material is less at high temperature, hence it requires less
force and energy.

40. Disadvantages of Hot Forging
• The properties of hot forged metals are obtained by subsequent
heat treatment. This requires additional cost, which can be avoided
if using cold forging.
• Less precise dimensional tolerance.
• The cooling process should be also performed under special
conditions; otherwise there is a risk of warping.
• The grain structure of forged metals may vary and there is always a
possibility of reactions between the atmosphere and the work
piece.

41. The cold forging manufacturing process is performed at room
temperature. The workpiece is squeezed between two dies until it has
assumed their shape. Cold forging extrusion is one of the most common
manufacturing techniques, widely used in the production
of automotive components. It is prefer for soft material like Aluminium.
The Cold Forging Manufacturing Process
Advantages of Cold Forging
• cold forged parts require very little or no finishing work.
• Cold forged parts offer a good level of attainable dimensional accuracy and
excellent surface quality.
• There is no warping(bending) of component.
• There is no reaction between atmosphere and metal, so there is no
formation scales on the surface.

42. Disadvantages of Cold Forging
• cold forged metals are less ductile.
• cold forging extrusion requires also a heat treatment to
eliminate possible cracks
• It requires heavy and powerful machines, high energy
and high die force.

43. Comparison Between Hot Forging and Cold Forging
Sr
no.
Parameter Hot Forging Cold Forging
1. Definition Above
recrystallization
temperature
Below
recrystallization
temperature
2. Force & energy
requirement
low high
3. Machine requirement light heavy
4. Dimensional accuracy poor Good
5. Ductility of component increases decreases
6. Reaction with Atm. Occur Do not occur
7. Warping of metal Takes place Do not Takes place
8. Residual stresses absent Present
9. Material used for
component
Need not to be soft soft

44. Classification based on Types of Die
The material or work piece is
deformed between two flat
dies or dies of very simple
shape.
OPEN DIE FORGING

45. Classification based on Types of Die
The material or work
piece is deformed
between two dies which
have impression of
desired shape.
CLOSED DIE FORGING

46. Classification based on Mode of Application of Compressive Force
Hand forging is the
process of
deforming the hot
workpiece into
desired shape by
applying repeated
blows of hand held
hammer.
HAND FORGING PROCESS

47. The initial cost of hand forging setup is low.
The cost of components produced by hand forging is low.
The quality of forging is dependent on the skill of the operator.
Used for making small components of simple shape.
Since the rate of production is low it is not suitable for mass
production.
HAND FORGING PROCESS

48. The workpiece is deformed into
desired shape by raising the die
and allowing it to fall so as to
impart the blow or impact on
the material.
The impact force is proportional
to the combined weight of the
ram and upper die and the
stroke of the ram.
DROP FORGING PROCESS

49. The quality of forging is consistent and good.
Medium sized components can be forged.
Suitable for mass production because rate of production is high.
The initial cost of drop forging process is high.
The process generates lot of noise.
DROP FORGING PROCESS

50. The workpiece is deformed into desired
shape by slow squeezing action.
The gradual motion of the upper die
transfers the compressive force uniformly
and gradually to the hot material so as to
deform it to the desired shape.
The compressive force is proportional to
the cross-sectional area of the cylinder
and the pressure of the hydraulic fluid.
PRESS FORGING PROCESS

51. It is faster as only one squeeze is needed per component.
As the force is transferred uniformly & gradually to the hot
material it results in uniform material properties.
Large sized components (upto 125 kg & 3 m long) can be forged.
The operation is quieter than drop forging process.
The initial cost of setup is high.
The running cost of press forging process is high.
PRESS FORGING PROCESS

52. The cross-section of workpiece is increased locally with a
corresponding reduction in its length by slow squeezing action.
Apart from the direction of operation (i.e. horizontal direction),
the process is similar to press forging.
MACHINE FORGING PROCESS

54. Sheet Metal Working is the
process of manufacturing the
components or parts from the
sheet-metal of thickness ranging
from 0.1 mm to about 6 to 8 mm.
The sheet metal working is
generally carried out with machine
tools called as press. Therefore, it is
also known as press working.

55. Components produced are light in weight.
Components are cheap.
Rate of production is high.
Components have high dimensional accuracy & surface finish.
Sheet metal working does not require skilled labour.

56. There is limitation on the thickness of metal used.
Sheet metal components have relatively low strength.
Automobile body parts.
Aircraft body parts.
Steel furnitures.
Utensils
Electronic appliances

57. SHEETMETALWORKING

58. Piercing

59. Punching

60. Blanking

61. Perforating

62. PERFORATED SHEETS

63. Slitting

65. Lancing

67. Notching

68. Drawing and Deep Drawing
Bending
Forming
Coining
Embossing

69. Drawing and Deep Drawing

70. Bending is a metal forming process by which a straight length
metal is transformed into a curved length.
It is common forming process for changing the metal sheet into
angles or channels.
Commonly used bending methods are:
V-Bending
U-Bending
Edge Bending
Angle Bending
Curling
Bending

71. V-Bending

72. U-Bending

73. Edge Bending

74. Angle Bending

75. Curling

76. Forming is a process of shaping a flat metal sheet into a
surface of desirable profile.
Examples: Automobile and aircraft body parts, steel furnitures,
toys, etc.
Forming

77. Coining is a process of cold squeezing of metal in which all the
surfaces are confined within a set of dies.
The pressure applied is about 6 times the strength of the metal
blank and the metal flows in cold state & fills up the cavity.
Examples are: Coins, medals, badges, etc.
Coining

78. Embossing is the process of producing the depressed or
raised impression of letters, figures & designs on metal sheets.
Does not require high pressure as required by coining process.
Examples are: Nameplates, identification tags, aesthetic designs.
Embossing

80. Introduction
• Manufactured individual product joined to form
the product.
• E.g. Bridges, Automobile. In railway rail joints,
steel furniture, boilers, ship bodies etc.
• Types:
1. Welding
2.Brazing
3.Soldering
4.Mechanical fastners (rivets, screw, nut bolts)
5.Adhesive bonding

81. Welding
• It is process of joining of two metallic parts
together by heating them to a plastic or semi
molten state, with or without the application of a
pressure and with or without filler material.
• Inputs:
1. Heat: obtained from electric energy, combustion
of gases, chemical reaction
2. Application of pressure
3. Filler material (welding rod)

82. Advantages of welding
• these are processes that can be performed manually,
semi-automatically, or completely automatically;
• continuous welds provide fluid tightness (so welding is
the process of choice for fabricating pressure vessels);
• welding (better than most other joining processes) can
be performed remotely in hazardous environments
(e.g., underwater, in areas of radiation, in outer space)
using robots;
• low costs.
• Welds can be effectively used for producing
complicated structure.
• Joints can be produce at much faster rate

83. Limitations of Welding
• It is permanent joint , not possible to
disassemble the two parts
• Joints weak against vibration
• Quality and strength depends on skill of
operator
• It produces residual stresses and distortion of
workpiece
• Gives harmful radiation like light, fumes,
spatters

84. Applications

85. Classification
Welding process
Pressure(plastic)
welding
Non pressure
(fusion) welding
Electric arc
welding
Gas welding
Non pressure
thermit welding

86. • Pressure welding: The two metal parts to be
jointed are heated to a plastic state and forged
together by an external pressure to make the
joint.
• Non-Pressure welding: The two metal parts to
be jointed are heated to a semi molten state and
allowed to solidify to make the joint without
application of external pressure.
• Types of Non-Pressure welding:
1.Electric Arc Welding
2.Gas Welding
3. Non-pressure Thermit Welding

87. Electric Arc Welding

89. Advantages of Electric Arc Welding
• Highly versatile process can be used for thin as
well as thick sections
• Used for any complicated shapes
• Produce good quality weld of high strength
• Setup is simple and portable and least
expensive
• Does not require external pressure

90. Limitations of Electric Arc Welding
• Requires filler material
• Downtime is more because electrode is consumable
• Skill operator is required
Applications of Electric Arc Welding
• Manufacturing of bridges, transmission towers,
electric towers, site erection, pressure vessel, boilers,
storage tank, pipelines, nuclear reactors, window
grills etc.

92. Shielded metal arc welding
• High temperature produces 2400 to 4000 deg. C
• flux coating produces protective gas shield over
molten metal and cover the weld also protects it
from oxidation

93. Power Source in Arc Welding
• Direct current (DC) vs. Alternating current (AC)
– AC machines less expensive to purchase and
operate, but generally restricted to ferrous metals
– DC equipment can be used on all metals and is
generally noted for better arc control

94. Arc Shielding
• At high temperatures in AW, metals are
chemically reactive to oxygen, nitrogen, and
hydrogen in air
– Mechanical properties of joint can be degraded by
these reactions
– To protect operation, arc must be shielded from
surrounding air in AW processes
• Arc shielding is accomplished by:
– Shielding gases, e.g., argon, helium, CO2
– Flux

95. Flux
A substance that prevents formation of oxides
and other contaminants in welding, or
dissolves them and facilitates removal
• Provides protective atmosphere for welding
• Stabilizes arc
• Reduces spattering
• fluxes-carbonate of
soda, potash, charcoal, coke etc

96. SMAW Applications and Products
• Steel fabrication of structural shapes (e.g.,
I-beams)
• Seams for large diameter pipes, tanks, and
pressure vessels
• Welded components for heavy machinery
• Most steels (except high C steel)
• Not good for nonferrous metals

97. Tungsten Inert gas arc welding
• Inert gases: helium, argon, carbon dioxide
• Inert gas flowing through the nozzle serves the
following purposes: 1.removes contamination
2.protects molten metal 3.cools the electrode
• High temperature produces 2400 to 4000 deg. C

98. • It produces high quality and clean welds on
almost any material
• It is suitable for thinner metal sheets with
thickness less than 6mm
• Widely used in fabrication of stainless steel
and other non-ferrous process equipment,
used in pharmaceutical and food processing
• Wide range of material used like carbon steels,
stainless steel, CI,Al,Cu,Ti,Ni,Mg etc

99. Metal Inert Gas Arc Welding
• Consumable metal electrode i.e. filler material
(having same composition as the workpiece)

100. Brazing
• Brazing is the process of
joining two work pieces,
made of similar or
dissimilar materials, by
heating them to a
specified temp. above
450 deg. C But below
the melting temp. of
work piece and using
non-ferrous filler
material. (alloys of
copper, silver, nickel)

101. Advantages of brazing
• Can join large variety of dissimilar metals
• Different thickness of work pieces can join (thin
sheets and pipes can’t join by welding)
• Non metals can be joined
• Good for mass production
• Produces pressure tight and corrosion resistance
joints
• it require little or no finishing other than flux
removal

102. Limitations of brazing
• Strength is lower than weld joint
• Requires tightly mating parts to obtain the desired fit
• Cost of filler material and machinery is high
Applications of brazing
• (a) Brazing is used for fastening of pipe fittings, tanks,
carbide tips on tools, radiators, heat exchangers,
electrical parts, axles, etc.
• (b) It can join cast metals to wrought metals,
dissimilar metals and also porous metal components.
• (c) It is used to join band saws, parts of bicycle such
as frame and rims.

103. Soldering
• Soldering is the
process of joining two
work pieces, made of
similar or dissimilar
materials, by heating
them to a specified
temp. below 450 deg.
C using filler material.
(tin lead alloy, alloy of
antimony, zinc and
aluminum)

104. Advantages of Soldering
• Can join variety of dissimilar materials
• Temp. is below melting temp. of material hence no change in
mechanical properties
• Join work pieces of different thickness
• Simple & cheaper
• It requires no finishing
• Easy realignment. Parts can be easily realigned by reheating the joint,
re-positioning the parts and allowing the filler metal to solidify.
• Joints can be made be permanently or temporarily
Limitationsof Soldering
Strength of joint lower than braze joint
Large surface can’t be soldered easily because heating is not uniform
Lead is toxic

105. Applications of Soldering
• Soldering is used in plumbing, electronics, and
metalwork from flashing to jewelry.
• machine tools and some refrigeration and plumbing
components are often assembled and repaired by
the higher temperature silver soldering process
• Electronic soldering connects electrical
wiring and electronic components to printed circuit
boards

106. Comparison of welding, brazing and Soldering
Sr. no Comparison
parameter
welding brazing soldering
1 Definition It is process of
joining of two
metallic parts
together by
heating them
to a plastic or
semi molten
state, with or
without the
application of a
pressure and
with or without
filler material.
Brazing is the
process of
joining two
work pieces,
made of similar
or dissimilar
materials, by
heating them
to a specified
temp. above
450 deg. C But
below the
melting temp.
of workpiece
and using non-
ferrous filler
material.
Soldering is the
process of
joining two
work pieces,
made of similar
or dissimilar
materials, by
heating them
to a specified
temp. below
450 deg. C
using filler
material.

107. Sr. no Comparison
parameter
welding brazing soldering
2 Heating of
work pieces
Electric energy,
gas flame,
chemical
reaction
Gas flame,
furnace
Flame, electric
soldering iron
3 Strength of
joint
high Lower than
welding but
relatively good
Very low
4 Surface finish Not good good Not good
5 Thickness of
sheet to be
joined
Can’t join thin Thin sheets can
join
Thin sheets can
join
6 Cost costly costly cheap