Manufacturing Technology complete course

Manufacturing
Technology
15ME202
Unit I-Casting
Dr. ManidiptoMukherjee
Research Asst. Professor
Room ME-C 206
Mechanical Engg. Dept.
SRM University
Email. [email protected]/
[email protected]
Mob: 9831349152
Dr. S. Murali
Assistant Professor
Room ME-C 205
Mechanical Engg. Dept.
SRM University
Email. [email protected] /
[email protected]

Unit-I
2
Text books:
MikellP. Groover, “Fundamentals of Modern Manufacturing Materials,
Processes, and Systems”,4
th
Edition, John Wiley & Sons, Inc., 2010
SeropeKalpakjian, Steven R. Schmid“Manufacturing Engineering and
Technology” Pearson India, 6
th
Edition, 2009

3
Introduction -Manufacturing
Manufacturing
Latin: manus(hand) + factus(make)
Manufacturingis the process of converting raw materials into
useful/valuable products.
What is Manufacturing?
Two ways to define manufacturing: (a) as a technical process, and (b) as an economic process.

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Manufacturing Includes
i) Design of the product
ii) Selection of raw materials and
iii) The sequence of processes through which the product will be
manufactured.
Any Product in the engineering industry will be manufactured in the below
methods
1. By totally deforming the metal to the required shape. (Casting /Forming)
2. By joining two metals. (Welding)
3. By removing the excess material from the raw stock.(Machining)
Introduction -Manufacturing

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ProductLifeCycle

Classification of the four engineering materials
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Classification of manufacturing processes.
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Engineering stress–strain plot
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Classification of solidification processes.
9

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Castingis amanufacturingprocess by which a liquid material is
usually poured into amould, which contains a hollow cavity of the
desired shape, and then allowed to solidify.
What is Casting?

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Introduction -Casting
Castingprocess is one of the earliest metal shaping techniques
known to human being.
The casting process was discovered probably around 3500 BCin
Mesopotamia.
Castingis amanufacturingprocess by which a liquid material is
usually poured into amould, 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 mould to complete the process.

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Introduction -Casting

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Casting terms?
Flask or mould box (cope & drag)
Pattern
Parting line
Bottom board
Facing sand
Moulding sand
Parting sand
Pouring basin
Gate
Riser

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Introduction -Casting

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Introduction -Pattern
Incasting, apatternis a replica of the
object to be cast, used to prepare the cavity
into which molten material will be poured
during the casting process.
The quality of the casting produced depends
upon the material of the pattern, its design,
and construction.

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What is Pattern?
Incasting, apatternis a replica of the object to be cast, used to
prepare the cavity into which molten material will be poured during
the casting process.

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Introduction –Pattern Material
Patterns may be constructed from the following materials:
wood, metals and alloys, plastic, plaster of Paris, plastic and
rubbers, wax, and resins.
Each material has its own advantages, limitations, and field of
application.

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Introduction –Pattern Material
Wood
Easily available, Low weight, Low cost
It absorbs moisture and hence dimensions will change
Lower life
Suitable for small quantity production and very large size castings
Metal
Used for mass production
For maintaining closer dimensional tolerances on casting
More life when compared to wooden patterns
Few of the material used include CI, Al, Fe, Brass etc.
Al is widely used

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Introduction –Pattern Material
Polystyrene
Used for prototype (single piece) castings
Also known as Disposable patterns
Plastic
Low weight
Easier formability
Do not absorb moisture
Good corrosion resistance

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Introduction –Pattern Material
The pattern material should be
Easily worked, shaped and joined
Light in weight
Strong, hard and durable
Resistant to wear and abrasion
Resistant to corrosion, and to chemical reactions
Dimensionally stable and unaffected by variations in temperature and
humidity
Available at low cost

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Single piece pattern
Split piece pattern
Loose piece pattern
Match plate pattern
Sweep pattern
Gated pattern
Skeleton pattern
Cope and Drag pattern
Introduction –Types of Pattern

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Introduction –Types of Pattern
Single piece pattern
Split piece pattern

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Loose piece pattern
Match plate pattern
Introduction –Types of Pattern

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Sweep pattern
Gated pattern
Introduction –Types of Pattern

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Skeleton pattern
Cope and Drag pattern
Introduction –Types of Pattern

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Pattern Allowance
Why are allowances necessary?
Final dimensions of casting are different from pattern because of
various reasons….
Types of allowances
Shrinkage Allowance
Machining Allowance
Draft (or) Taper Allowance
Distortion Allowance
Rapping (or) Shake Allowance

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Types of Pattern Allowance
Shrinkage Allowance
Liquid shrinkage refers to reduction in volume when metal changes
from liquid to solid state. Riser are used to compensate this.
Solid shrinkage refers to reduction in volume when metal loses
temperature in solid state. To compensate this shrinkage allowance is
used.
Pattern is made slightly bigger. This difference in size of the pattern is
called shrinkage allowance.
Amount of allowance depends upon type of material, its composition,
pouring temperature etc.

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Types of Pattern Allowance
Shrinkage Allowance

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Types of Pattern Allowance
Machining Allowance
It’s given to get better surface finish.
Provided to compensate for machining on casting.
Pattern is made slightly bigger is size.
Amount of allowance depends upon size and shape of casting, type of
material, machining process to be used, degree of accuracy and surface
finish required etc.
A layer of 1.5–2.5 mm thick material has to be provided all round the
casting

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Types of Pattern Allowance
Machining Allowance (example)
Geometric Dimensioning and Tolerancing (GD&T) is a system for defining and
communicating engineering tolerances. It uses a symbolic language on engineering
drawings and computer-generated three-dimensional solid models that explicitly
describes nominal geometry and its allowable variation.

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Types of Pattern Allowance
Machining Allowance

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Types of Pattern Allowance
Draft (or) Taper Allowance
Provided to facilitate easy withdrawal of the pattern.
Typically it ranges from 1 degree to 3 degree for wooden patterns.

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Types of Pattern Allowance
Draft (or) Taper Allowance

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Types of Pattern Allowance
Distortion Allowance
A U-shaped casting will be distorted during cooling with the legs
diverging, instead of parallel.
To compensate, the pattern is made with legs converged but, as the
casting cools, the legs straighten and remain parallel.

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Types of Pattern Allowance
Rapped (or) Shake Allowance
To remove the pattern out of mould cavity, it is slightly rapped or
shakedto detach it from the mould cavity.
To compensate, negativeallowance –subtracted from pattern
dimension.

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Moulding
A mould is a hollowed-out block that is filled with a liquid like metal,
plastic, …. A mould is the counterpart to a Cast.
Types of moulding
According to the method used
1.Floor moulding
2.Bench moulding
3.Pit moulding
4.Machine moulding
According to the mould materials
1.Green sand moulding
2.Dry sand moulding
3.Loam sand moulding
4.Core sand moulding
Other moulding processes
1.Shell moulding
2.Permanent mould casting
3.Carbon dioxide moulding

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Types of Moulding -According to the method used (1/4)
1.Floor moulding
Used for preparing the mould of heavy and large size of jobs
Floor itself acts as a drag
It is preferred for such rough type of casting where the upper surface
finish has no importance.

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2. Bench moulding
It is done on a work bench of a height convenient to the moulder.
Best suited to the mould of small and light items which are to be
casted by non-ferrous metals.
Types of Moulding -According to the method used (2/4)

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3. Pit moulding
Large sizes of jobs which cannot be accommodated in moulding boxes
are frequently moulded in pits.
Here, the pit acts as a drag. Generally, one box, i.e. cope is sufficient to
complete the mould.
Types of Moulding -According to the method used (3/4)

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4. Machine moulding
It is preferred for mass production of identical casting as most of the
moulding operations such as ramming of sand, rolling over the
mould, and gate cutting etc. are performed by moulding machine.
Therefore, this method of moulding is more efficient and economical in
comparison to hand moulding.
Types of Moulding -According to the method used (4/4)

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Types of Moulding -According to the mould materials
Types of moulding
According to the mould materials
1.Green sand moulding
2.Dry sand moulding
3.Loam sand moulding
4.Core sand moulding

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Types of Moulding -According to the mould materials (1/4)
1.Green sand moulding
Suitable proportions of silica sand (85 -92 %), bentonite binder (6-12
%), water(3-5 %) and additives are mixed together to prepare the
green sand mixture.

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Types of Moulding -According to the mould materials (1/4)
1.Green sand moulding
Advantages
Green sand moulding is adaptable to machine moulding.
No mould baking or drying is required.
There is less mould distortion than in dry sand moulding.
Time and cost associated with mould baking or drying is eliminated.
Green sand moulding provides good dimensional accuracy across
the parting line.
Disadvantages
Green sand moulds possess lower strengths.
They are less permeable.
There are more chances of defects (like blow holes etc.) occurring in
castings made by green sand moulding.
Surface finish deteriorates as the weight of the casting increases.
Dimensional accuracy of the castings decreases as their weight
increases.

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Types of Moulding -According to the mould materials (2/4)
2. Dry sand moulding
Here, in the preparation of the mixture for dry sand moulding, special
binding material such as resin, molasses, flour, or clay are mixed to
give strong bond to the sand.
All parts of mould are completely dried before casting.
Dry sand moulding is widely used for large size of work such as parts
of engine, large size of fly wheel and rolls for rolling mill.
This process is costlierthan green sand moulding but much superior
in quality.

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Types of Moulding -According to the mould materials (3/4)
3. Loam sand moulding
Loam sand moulding are prepared with coarse grained silica sand,
clay, coke, horse manure and water.
Sand containing up to 50% clay is used.
Used for very heavy casting.

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Types of Moulding -According to the mould materials (4/4)
4. Core sand moulding
For core sand moulding, mixture is prepared with silica sand, olivine,
carbon and chamottesands.
Sand that contains more than 5% clay may not be used as core sand.

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Types of Moulding –Other moulding process (1/3)
1. Shell moulding
It is an efficient and economical method for producing steel castings.
The process was developed by Herr Croning in Germany during World War-II and is
sometimes referred to as the Croning shell process
Fine silica sand that is covered in a thin (3–6%) thermosetting phenolic resin and
liquid catalystis dumped, blown, or shot onto a hot pattern.
The pattern is usually made from cast iron and is heated to 230 to 315 °C (450 to 600 °F).

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Types of Moulding –Other moulding process (2/3)
2. Permanent mould casting
Steps in permanent mold casting: (1) mold is preheated and coated

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Types of Moulding –Other moulding process (2/3)
2. Permanent mould casting
(2) cores (if used) are inserted and mold is closed,
(3) molten metal is poured into the mold, where it solidifies.

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Types of Moulding –Other moulding process (3/3)
3. Carbon dioxide moulding
Carbon dioxide moulding also known as sodium silicate process is one
of the widely used process for preparing moulds and cores.
In this process, sodium silicate is used as the binder. But sodium
silicate activates or tend to bind the sand particles only in the
presence of carbon dioxide gas. For this reason, the process is
commonly known as CO
2process.

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Moulding Sand
It is used to prepare mould cavities
Moulding sands may be of two types namely natural or synthetic
The common sources of moulding sands available in India are as
follows:
1.Batalasand ( Punjab)
2.Ganges sand (Uttar Pradesh)
3.Oyariasand (Bihar)
4.Damodarand Barakarsands (Bengal-Bihar Border)
5.Londhasand (Bombay)
6.Gigatamannusand (Andhra Pradesh) and
7.Avadiand Veeriyambakamsand (Madras)

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Properties of Moulding Sand (1/2)
Refractoriness-It is the ability of the moulding material to resist the
temperature of the liquid metal to be poured so that it does not get fused
with the metal. Therefractorinessof the silica sand is highest.
Permeability -The grain size, shape and distribution of the foundry sand,
the type and quantity of bonding materials, the density to which the sand is
rammed, and the percentage of moisture used for tempering the sand are
important factors in regulating the degree ofpermeability

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Properties of Moulding Sand (2/2)
Cohesiveness is defined as the ability to retain a given shape. Thus due to
cohesiveness, rammed moulding sand particles are bonded together once
the pattern is withdrawn from mould.
Green strength -Green means containing water while strength refers to
the compressive strength of moulding sand. Therefore, the property of the
green sand to retain the shape of the mould.
Dry strength -Ability of the dry sand to retain the shape of mould cavity
Adhesiveness –property of the moulding sand by which it is capable to
adhere to the surface of the moulding flask.
Flowabilityor plasticity and Collapsibility

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Types of Moulding Sand

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Types of Moulding Sand
Green sand
Silica sand + Clay 18 –30 % + Moisture 6 to 8 %
Moulds prepared by this sand are not requiring backing
Employed for production of ferrous and non-ferrous castings.
Dry sand
Green sad that has been baked in suitable oven after the making mould
and cores
Suitable for larger casting

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Types of Moulding Sand
Facing sand
It is sprinkled on the inner surface of the moulding cavity to give better
castings
Backing sand
Used to back up the facing sad and is used to fill the whole volume of
the moulding flask or box
Parting Sand
This is clean-clay free silica sand
Between cope and drag box

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Gate and Riser

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Core
A core is a device used in casting process to produce internal cavities and
re-entrantangles.
Most commonly used in sand casting.
Cores are made of sand.

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Core
A core consists of two portions:
The body of the core and
One or more extensions called prints
Prints

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Core prints
The core prints are necessary to support the core in the mould.
The core print is an added projection on the pattern and it forms a seat in
the mould on which the sand core rests during pouring of the mould.
The core print must of the adequate shape and the size so that it can
support the weight of the core during the casting operation.

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Core, Core Print & Core Box
Core
Core print
Core box: the mould or die
used to produce casting cores

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Characteristics of Core
Green strength –sufficient strength to hold up its shape till it is backed
Dry strength –sufficient strength to resist bending forces due to
hydrostatic pressure from the liquid (molten metal), when core is placed
inside the mould
Refractoriness–core is surrounded on all sides by molten metal and
should have high refractoriness.
Permeability–gases evolved may pass through the core to escape and
should posses sufficient permeability.

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Characteristics of Core
Collapsibility –should shrink as molten metal shrinks during solidification
Friability –should get dismantled easily once the casting is completely
cooled.
Smoothness–surface of core should be smooth to have better surface
finish.
Low gas emission –emission of gases from core should be as low as
possible to avoid voids formed inside core

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Chaplets
Cores are usually supported by two core prints in the mould.
Cantileveredcore??
Small metal support that bridge the gap between the mould surface and
the core.
Chaplets are used to give support for cantilevered core.
The caplets must be of the same or similar material as the metal being
cast.

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Core sand
Core sand must be stronger than moulding sand
Core sand = Sand grains + Binders + Additives
Sand grains containing more than 5% clay is not used to make core
Excessive clay reduces the permeability and collapsibility of the core
Binders
Organic binders tend to burn away under the heat of molten metal and
hence increases the collapsibility of the core.
Binders: linseed oil, dextrin, molasses, resins, etc

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Types of Cores
The selection of the correct type of core depends on production quantity,
production rate, required precision, required surface finish, and the type of
metal being used.
Types
Based on material used for making cores
Sand cores
Metal cores
Based on nature of use
Dispensable (in sand casting)
Permanent (in die casting)
Based on shapes and positions of the cores in prepared moulds
Horizontal cores
Vertical cores
Balanced cores
Hanging cores
Cover cores
Wing cores
Kiss cores

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Types of Cores
Horizontal cores
This core is usually in cylindrically form
Held horizontally along the parting line of the mould
Ends of core rests in the seats provided by the core prints in the
pattern

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Types of Cores
Vertical cores
Similar to a horizontal core except that it is fitted in the mould with its
vertical axis
Two ends of the mould sits on the cope and drag portion of the mould.
Amount of taper on the top is more than the taper at the bottom of
the core.

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Types of Cores
Balanced cores
It is suitable when the casting has an opening only on one side and
only one core print is available on the pattern.

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Types of Cores
Cover core
It is used when the entire pattern is rammed in the drag and the core is
required to be suspended from the top of the mould.

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Types of Cores
Wing core
It is used when hole or recess is to be obtained in casting.

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Types of Cores
Hanging core
If the core hangs from the cope and does not have any support at the
bottom in the drag, it is referred to as a hanging core.
In this case, it may be necessary to fasten the core with a wire or rod,
which extends through the cope to a fastening on the top side of the
cope.

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Types of Cores
Kiss cores
When the pattern is not provided with core prints and no seat is
available for resting the core, the core is held in position between the
cope and drag simply by the pressure of the cope.
They are useful when a number of holes are required in casting
Dimensional accuracy with regard to the relative location of the holes is
not important

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Core making
Cores for sand casting are manufactured by packing specially prepared sand
in core boxes.
Core making: sand preparation core shooting coating/treatment 
placement in mould.
The cavity in a core box is a negative replica of the corresponding part
feature.

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Core boxes
Core boxes are used for making cores.
Made up of wood or metal
Types
Half core box
Spilt core box
Dump core box
Loose piece core box
Strickletype core box

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Shell Casting
It is a process in which the sand mixed with a thermosetting resin is
allowed to come into contact with a heated metallic-pattern plate, so that a
thin and strong shell of mould is formed around the pattern.
The strong shell of mould act as a mould cavity.

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Shell Casting
Pattern made of a ferrous metal or aluminum
Heated to a range of 175 to 370 degree Celsius
Coated with a parting agent (silicone)
Clamped to a box or chamber
Dump boxfine sand, 2.5 to 4 % thermosetting resin binder (phenol-
formaldehyde)
Shell usually 5 to 10 mm

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Shell Casting
Advantage
Very suitable for thin sections like petrol engine cylinder
Excellent surface finish
Good dimensional accuracy of order of 0.002 to 0.003 mm
Mass production.
Disadvantage
Initial cost is high.
Specialized equipment is required.
Resin binder is an expensive material.
Limited for small size.

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Shell Casting
Application
Suitable for production of Al, Cu and ferrous metals
Cylinder heads for air cooled IC engines
Automobile transmission parts
Chain seat bracket
Refrigerator valve plate etc.

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Shell Casting <Video>

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Investment Casting
Investment casting uses a piece of ceramic mould. The mould is prepared
by surrounding the ceramic material over the wax or plastic pattern. Once
the ceramic material solidifies, the wax replica is melted and drained out
from the mould and the metal is poured into the mould cavity.

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Investment Casting

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Investment Casting <Video>

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Investment Casting
Advantages
Complex shapes can be produced
Very thin sections can be produced
Because of using fine grain sand products with good surface finish can be
produced
Little or no machining is required
Controlled mechanical properties
Disadvantages
Limited to size and mass of casting
More expensive
Application
Jewellery, surgical instruments, vanes and blades of a gas turbine
Fire arms, Steel valve bodies and impellers for turbo chargers, etc.

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Die Casting
It is a moulding process in which the molten metal is injected under high
pressure and velocity into a split mould die.
It is also called pressure die casting.
The pressure is generally created by compressed air or hydraulic
The pressure varies from 70 to 5000 kg/cm
2
and is maintained while the
casting solidifies.
Types: hot and cold chamber
Any narrow sections, complex shapes can be easily produced.

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Die Casting <Video>

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Die Casting (Hot Chamber)
Metals like Zinc, tin and lead alloys are casted in hot chamber die casting having
melting point below 390°C

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Die Casting (Cold Chamber)
Aluminium alloys are casted in cold chamber die casting machine.
Aluminium dissolves ferrous parts in the die chamber and hence preferred
to be used in cold chamber die casting.
Continuous contact of molten metal is avoided by using a ladle for
introducing molten metal directly to the machine.

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Advantages
High production rate.
High accuracy in part dimensions.
Smooth surface finish for minimum mechanical finishing.
Ability to make many intricate parts such as hole opening slot trademark number
etc.
Much thinner wall sections can be produced which can’t be produced by other
casting methods.
Varieties of alloys can be used as per design requirements. For example zinc can
be used for intricate forms and plasticity, aluminumfor higher structural strength,
rigidity and light weight.
Ability to cast inserts such as pins studs shafts, fasteners etc.
Die Casting

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Die Casting
Disadvantages
Micro porosity in the die casting products is a common problem because of
faster solidification, trapped air and vaporized die lubricants.
Undercuts cannot be found in simple two piece dies.
Hollow shapes are not readily casted because of the high metal pressure.
Limited sizes of the products can be produced based on the availability of the
equipment.
High melting temperature alloys are practically not die casted.

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Die Casting
Applications
Die casting process is preferred for nonferrous metal parts of intricate shapes.
Examples are automobiles appliances, hand tools, computer peripherals, toys,
optical and photographic equipment etc

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Centrifugal Casting
Producing casting by pouring the molten metal into a rapidly rotating
mould.
The metal is thrown out towards the mould face by the centrifugal force
under considerable pressure.
The results in better mould filling and a casting with dencergrain structure,
which is virtually free of porosity
The mould is rotated at high speed (300 to 3000 rpm) so centrifugal force
distributes molten metal to outer regions of die cavity.

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Centrifugal Casting

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Centrifugal Casting

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Centrifugal Casting

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Centrifugal Casting <Video>

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Centrifugal Casting
Types of centrifugal casting
True centrifugal casting
Semi-centrifugal casting
Centrifuging

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Centrifugal Casting
True centrifugal casting
Molten metal is poured into rotating mold to produce a tubular part
In some operations, mould rotation commences after pouring
rather than before.
Parts: pipes, tubes, bushings, and rings
Outside shape of casting can be round, octagonal hexagonal, etc.
but inside shape is perfectly round, due to radially symmetric forces.

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Centrifugal Casting
True centrifugal casting

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Centrifugal Casting
Semicentrifugal casting
Centrifugal force is used to produce solid castings rather than tubular
parts.
Moulds use risers at center to supply feed metal
Density of metal in final casting is greater in outer sections than at
center of rotation
Often used on parts in which center of casting is machined away,
thus eliminating the portion where quality is lowest
oExamples: wheels and pulleys

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Centrifugal Casting
Semicentrifugal casting

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Centrifugal Casting
Centrifuged casting
Mold is designed with part cavities located away from axis of rotation,
so molten metal poured into mold is distributed to these cavities by
centrifugal force
Used for smaller parts
Radial symmetry of part is not required as in other centrifugal
casting methods.

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Centrifugal Casting
Centrifuged casting

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Defects in Castings
Types of defects
Inspection methods
Moulding related defects
Filling related defects
Solidification related defects
Defects analysis

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Types of Defects
Based on location
External
Internal
Based on Type
Geometric
Integrity
Based on size/severity
Small/Minor
Large/Major
Based on Process
Moulding-related
Filling-related
Solidification-related
Based on Cause
Raw materials
Product design
Tooling design
Process parameters
Process control
Based on Stage
Casting
Rough machining
Finish machining
Service
Based on Reparability
Repairable
Irreparable

106
Inspection Methods (Defects)
Destructive
Sectioning, Machining
Mechanical testing
Chemical testing
Non-Destructive
Visual: large external defects
Dimensional: size defects
Pressure testing: leakage
Radiography: internal holes
Ultrasound: internal discontinuities
Eddy current: hardness, structure
Magnetic particle: sub-surface discontinuities
Dye Penetrant: defects with opening to surface.

Misruns
Causes
Low pouring temperature
Low fluidity
Slow pouring
Cross section of the mold cavity is too thin
Very high moisture content
Remedies
Provide hotter metal at cupola spout, reduce heat losses in ladles by using
flux coverings
Increase carbon and phosphorous
Reduce moisture content
Keep runner bush full of metal during pouring
107
Defects in Casting, Causes and Remedies

Cold shut
Two portions of metal flow together but there is a lack of fusion due to
premature freezing
Causes and Remedies are similar like misruns
108
Defects in Casting, Causes and Remedies

Cold shot
Metal splatters during pouring and solid globules form and become entrapped
Causes
Wrong pouring procedures
Improper gating system designs
Remedies
Proper gating system design
109
Defects in Casting, Causes and Remedies

Blowholes
Causes
Low vent on moulding or core sands
Hard ramming
High moisture content
Very hard cores
Insufficient venting in cores
Remedies
Increase vent by use of vent wire
Avoid excess ramming
Reduce moisture to minimum
Reduce oil in sand
Ensure vents are clear
110
Defects in Casting, Causes and Remedies

Micro porosity
It is generally present in fine grain alloy castings when the solidification is too
rapidfor the micro voids to segregate to the liquid pool.
The porosity is in the form of small, irregular voids.
Causes
Rapid solidification if the mold or casting temperature is too low.
111
Defects in Casting, Causes and Remedies

Shrinkage cavity
Depression in surface or internal void caused by solidification shrinkage that
restricts amount of molten metal available in last region to freeze
Causes
Lack of molten metal
Missing riser / Improper riser design
Improper design of pattern
Remedies
Proper design of riser
Proper design of pattern
112
Defects in Casting, Causes and Remedies

113
Defects in Casting, Causes and Remedies
Pin holes
Formation of many small gas cavities at or slightly below surface of casting.
Caused by release of gas during pouring of molten metal.
To avoid improve permeability & venting in mould.

114
Moulding-related Defects
Improper Closure
Across parting plane: flash
Along parting line: mismatch

115
Filling-related Defects
Incomplete filling: cold shut, misrun
Gaseous entrapments: blow hole, gas porosity
Solid inclusions: sand inclusion, slag inclusion

116
Solidification related defects
Solidification shrinkage: Cavity, porosity
Hindered cooling contraction: hot tear, crack

117
Defects analysis
Individual Defect
Defect identification
Cause identification
Remedy specification
Defects over a batch/period
Quality control charts
Defect frequency (histogram)
Defect spectrum (pattern over time)
Expert Systems for Defects Analysis
Knowledge base (IF-THEN rules with confidence)
Inference Engine

118
Furnaces for Casting Process
Cupolas
Crucible furnaces
Electric-arc furnaces
Induction furnaces

119
Engineering Analysis of Pouring
Bernoulli’s theorem:
The sum of the energies (head, pressure, kinetic, and friction) at any two
points in a flowing liquid are equal. This can be written in the following
form:
Where,
h=head or height, cm (in),
p=pressure on the liquid, N/cm
2
(lb/in
2
);
ρ= density; g/cm
3
(lbm/in
3
);
v =flow velocity; cm/s (in/sec);
g = gravitational acceleration constant, 981 cm/s
2
(386 in/sec
2
; and
F= head losses due to friction, cm (in).
Subscripts 1 and 2 indicate any two locations in the liquid flow.

120
Engineering Analysis of Pouring
If we ignore friction losses (to be sure, friction will affect the liquid flow
through a sand mold), and assume that the system remains at atmospheric
pressure throughout, then the equation can be reduced to
Let us define point 1 at the top of the sprueand point 2 at its base. If point 2 is
used as the reference plane, then the head at that point is zero (h
2= 0) and h
1
is the height (length) of the sprue. When the metal is poured into the pouring
cup and overflows down the sprue, its initial velocity at the top is zero (v
1= 0).
Hence, the Equation further simplifies to
Or

121
Engineering Analysis of Pouring
Mass Continuity law:
The volume rate of flow remains constant throughout the liquid. The
volume flow rate is equal to the velocity multiplied by the cross-sectional
area of the flowing liquid.
Where, Q = volumetric flow rate, cm
3
/s (in
3
/sec); v = velocity as before; A =
cross-sectional area of the liquid, cm
2
(in
2
); and the subscripts refer to any
two points in the flow system.
Using the previous equation of flow velocity, the continuity law can be written as2211 22 ghAghAQ 

122
Engineering Analysis of Pouring
Mold filling time, T
MF
Considering horizontal runner
where, T
MF= mold filling time, s (sec); V=volume of mold cavity, cm
3
(in
3
);
and Q= volume flow rate.
Mold filling time can be different for different gating system:tg
MF
ghA
V
T
2

For top gating system 
mtt
g
m
MF hhh
gA
A
T 
2
2
For bottom gating system

123
Gating Systems

124
Gating Ratios
Gating ratio: Spruearea : Runner area : Gate area
Non-pressurized:
has choke at the bottom of the spruebase, has total runner area and gate areas higher
than the spruearea. No pressure is present in the system and hence no turbulence. But
chances of air aspiration is possible. Suitable for Al and Mg alloys.
In this, Gating ratio = 1 : 4 : 4
Pressurized:
Here gate area is smallest, thus maintaining the back pressure throughout the gating
system. This backpressure generates turbulence and thereby minimizes the air aspiration
even when straight sprueis used. Not good for light alloys, but good for ferrous castings.
In this, Gating ratio = 2 : 2 : 1 or 1 : 2 : 1

125
Pouring Time
Purpose of Gating System
To fill the mould in the smallest time into the cavity
The time for complete filling of a mould referred as Pouring Time.
Too long pouring time requires a higher pouring temperature.
Too less a pouring time means turbulent flow in the mould, which makes
the casting defect-prone.
There is an optimum pouring time for any given casting.
Pouring time depends on casting materials, complexity of the casting,
section thickness, and casting size.

126
Problem of Pouring
A mold sprueis 20 cm long, and the cross-sectional area at
its base is 2.5 cm
2
. The spruefeeds a horizontal runner
leading into a mold cavity whose volume is 1560 cm
3
.
Determine: (a) velocity of the molten metal at the base of
the sprue, (b) volume rate of flow, and (c) time to fill the
mold.
Ans: 198.1 cm/s; 495 cm
2
/s; 3.2s

127
Solidification
Pure metal
Alloy

128
Solidification Time
The total solidification time is the time required for the casting to solidify
after pouring. This time is dependent on the size and shape of the casting
by an empirical relationship known as Chvorinov’srule.n
c
c
s
SA
V
kT









Where, T
S=total solidification time, min; V
C= volume of the casting, cm
3
(in
3
); SA
C=surface area of the casting, cm
2
(in
2
); n is an exponent usually
taken to have a value = 2; and k is the mold constant.

129

130
Three metal pieces being cast have the same volume, but
different shapes: One is a sphere, one a cube, and the other
a cylinder with its height equal to its diameter. Which piece
will solidify the fastest, and which one the slowest? Assume
that n = 2.
Problem of Solidification Time

131
Caine’s Method
The shrinkage occurs in three stages,
1.When temperature of liquid metal drops from Pouring to Freezing
temperature
2.When the metal changes from liquid to solid state
3.When the temperature of solid phase drops from freezing to room
temperature
The shrinkage for stage 3 is compensated by providing shrinkage
allowance on pattern, while the shrinkage during stages 1 and 2 are
compensated by providing risers.

132
Caine’s Method
Caine’s equation
Freezing ratio, &#3627408459;=
????????????
????????????&#3627408480;&#3627408481;????????????????????????
????????????&#3627408480;&#3627408481;??????????????????
????????????
&#3627408479;??????&#3627408480;??????&#3627408479;??????
&#3627408479;??????&#3627408480;??????&#3627408479;
The freezing ratio of the mould is defined as the ratio of cooling
characteristics of casting to the riser.
In order to feed the casting the riser should solidify last and hence freezing
ratio should be greater than unity.

133
Caine’s Method
Caine’s equation
&#3627408459;=
&#3627408462;
&#3627408460;−&#3627408463;
−&#3627408464;
Where, X = Freezing ratio
Y = Riser volume / Casting volume
a, b, c = Constant

•www.google.co.in
•www.researchgate.net
•www.youtube.com
•MikellP. Groover“Fundamentals of Modern Manufacturing Materials, Proc
esses, and Systems”,4
th
Edition,JOHNWILEY & SONS, INC.2010
•E.PaulDeGarmo, Black J.T and Ronald A. Kosher “Materials and Process
es, in Manufacturing”,EightEdition, Prentice –Hall of India, 1997
•James S Campbell “Principles of manufacturing materials and processes”
New Delhi : Tata McGraw-Hill ,1983
•SeropeKalpakjian,Steven R Schmid“Manufacturing Engineering and Tec
hnology” Pearson India, 4th Edition
134
Bibliography

135

Manufacturing
Technology
15ME202
Unit II-Mechanical
Working of Metals
Dr. ManidiptoMukherjee
Research Asst. Professor
Room ME-C 206
Mechanical Engg. Dept.
SRM University
Email. [email protected]/
[email protected]
Mob: 9831349152
Dr. S. Murali
Assistant Professor
Room ME-C 205
Mechanical Engg. Dept.
SRM University
Email. [email protected] /
[email protected]

2

3
Mechanical Working
Mechanical Working Objectives of metal working processes are to
provide the desired shape and size, under the action of externally applied
forces in metals.
Non-cutting or non machining shaping processes are referred to as
mechanical working processes.
material removal material removal ????

4
Types of Metal Working
Hot working
Mechanical processes which are done above recrystalisation
temperatureof the metal.
Cold working
Mechanical processes which are done below recrystalisation
temperatureof the metal.

5
Metal Working
Temperature at which recrystalisation phenomenon starts known as
recrystalisation temperature
Recrystalisation It can be defined as the nucleation and growth of stress-
free grains.

6
Metal Working
When a metal is heated and deformed under mechanical force, an energy
level will be reduced when the old grain structure starts disintegrating.
Simultaneously, an entirely new grain structure with reduced grain size
starts forming. It is called Recrystalisation.

7
Hot Working
Hot working: T>0.5T
m
Mechanical working of a metal above the recrystallization temperature
but below the melting point.
The recrystallization temperature of metal will be about 30 to 40% of its
melting temperature.
Types (example)
Forging, Rolling, Extrusion, Drawing

8
Hot Working
Advantages
Force requirement is less
Refined grain structure
No stress formation (no residual stresses)
Quick and economical
Suitable for all metals
Disadvantages
Poor surface finish
Less accuracy
Very high tooling and handling cost

9
Cold Working
Cold working: T<0.3T
m
Mechanical working of a metal below the recrystallization temperature
(room temperature)
Reduces the amount of plastic deformation that a material can undergo
in subsequent processing and requires more power for further working.
Types (example)
Drawing, Squeezing, Bending

10
Cold Working
Advantages
Better surface finish
High dimensional accuracy
Sheets and wires can be produced
Increased mechanical properties (ultimate tensile strength, yield strength,
hardness, fatigue strength, residual stresses)
Suitable for mass production.
Disadvantages
Stress formation in metal very high
No refined grain structure

11
Mechanical properties

12
Hot vs. Cold Working
Comparison
Hot working Cold working
Working aboverecrystallization te
mperature
Working below recrystallization te
mperature
Formation of new crystals No crystal formation
Surface finish not good Good surface finish (no oxidation)
No stress formation Internal stress formation
No size limit Limited size
Decreased mechanical propertiesIncreased mechanical properties
Increased ductility Decreased ductility

13
A heavily cold-worked structure has elongated grains and a large amount of residual stress (left). A moderate amount
of annealing causes the elongated grains to recover and new grains to form (center). Extended annealing is
associated with grain growth (right).

14
Rolling
One of the primary process to convert raw material into finished product.
Ingot’s are rolled into Slabs, Blooms, Billets by feeding material through
successive pairs of rolls.

15
Rolling
Some of the steel products made in a rolling mill

16
Rolling

17
Rolling
The draft: the work is squeezed between two rolls so that its
thickness is reduced by an amount.
The true strain and the average
flow stress The roll force
T=0.5FL
The torque
The power required per roll

18
Rolling Problem
A 300-mm-wide strip 25-mm thick is fed through a rolling mill with two
powered rolls each of radius = 250 mm. The work thickness is to be
reduced to 22 mm in one pass at a roll speed of 50 rev/min. The work
material has a flow curve defined by K = 275 MPaand n = 0.15, and the
coefficient of friction between the rolls and the work is assumed to be
0.12. Determine if the friction is sufficient to permit the rolling operation
to be accomplished. If so, calculate the roll force, torque, and
horsepower. Also determine the no. of passes required to make 12mm
thick plate.

19
Types of Rolling
Based on work piece geometry
Flat rolling –used to reduce thickness of a rectangular cross section
Shape rolling –square cross section is formed into a shape such as an
I-beam
Thread and gear rolling, Tube rolling, Ring rolling, Skew rolling
Based on work temperature
Hot rolling
Cold rolling

20
Hot Rolling
It is the most rapid method of forming metal into desired shapes by plastic
deformationthrough compressive stress by two or more than two rolls.
Ingots into smaller sections
Coarsestructure of cast ingot is converted into a finegrained structure

21
Hot Rolling

22
Hot Rolling
The crystals in parts are elongated in the direction of rolling, and they start
to reformafter leaving the zone of stress.
Hot rolling process is being widely used in the production of large number
of useful products such as rails, sheet metals, etc.

23
Hot Rolling
Function of roll
Pull the work into the gap
between them by friction
between work part and
rolls.
Simultaneously squeeze the
work to reduce its cross
section.

24
Hot Rolling

25
Cold Rolling
It is the most rapid method of forming metal into desired shape by plastic
deformationthrough compressive stresses using two or more than two rolls
with or without spraying water.

26
Cold Rolling
Below recrystalisation temperature (room temperature)
Increased mechanical strength
Greater surface finish compared to hot rolling
Cold rolling cannot be reducing the work piece thickness as much as hot
rolling in single process.

27
Cold Rolling (Residual stress during rolling)

28
Rolling Mills
Rolling mills massive and expensive
Configurations
Two-high
Three-high
Four-high
Cluster mill
Tandem rolling mill

29
Rolling Mills
Two-high two opposing rolls

30
Rolling Mills
Three-high work passes through rolls in both directions

31
Rolling Mills
Four-high backing rolls support smaller work rolls

32
Rolling Mills
Cluster mill multiple backing rolls on smaller rolls

33
Rolling Mills
Tandem rolling mill sequence of two-high mills
A series of rolling stands in sequence

34
Universal Mill

35
Rolling Defects
Rolling Defects
a)Waviness
b)Zipper cracks
c)Edge cracks
d)Alligatoring

36
Forging
Forging is the working of metal into a useful shape by hammering or
pressing.
Forging machines are now capable of making parts ranging in size of a bolt
to a turbine rotor.
Most forging operations are carried out hot. (cold and hot forging)
Up to 1150°C for Steel
360 to 520 °C for Al-Alloys
700 to 800°C for Cu-Alloys

37
Hot Forging
During hot forging, the temperature reaches above the recrystallization
point of the metal.
This kind of extreme heat is necessary in avoiding strain hardening of the
metal during deformation.
Isothermal forging is used to prevent the oxidation of certain metals, like
super alloys.
Up to 1150°C for Steel
360 to 520 °C for Al-Alloys
700 to 800°C for Cu-Alloys

38
Hot Forging
Advantages
Forged parts possess high ductility and offers great resistance to impact
and fatigue loads.
Forging refines the structure of the metal.
It results in considerable saving in time, labor and material as compared
to the production of similar item by cutting from a solid stock and then
shaping it.
Forging distortsthe previously created unidirectional fiberas created by
rolling and increases the strength by setting the direction of grains.

39
Hot Forging
Disadvantages
Rapid oxidation in forging of metal surface at high temperature results
in scaling which wears the dies.
The close tolerances in forging operations are difficultto maintain.
Forging is limited to simple shapes and has limitation for parts having
undercuts
Some materials are not readily worked by forging.
The initial cost of forging dies and the cost of their maintenance is high.

40
Cold Forging
Cold forging deforms metal while it is below its recrystallization point.
Cold forging is generally preferred when the metal is already a soft metal,
like aluminium.
This process is usually less expensive than hot forging and the end product
requires little, if any, finishing work.

41
Cold Forging
Advantages
Produces net shape or near-net shape parts
Cold forging is also less susceptible to contamination problems
Final component features a better overall surface finish.
Minimizes the cost
Easier to impart directional properties
Disadvantages
The metal surfaces must be clean and free of scale before forging occurs
The metal is less ductile
Residual stress may occur
Heavier and more powerful equipment is needed
Stronger tooling is required

42
Application of Forging
Forging is generally carried out on carbon alloy steels, wrought iron,
copper-base alloys, aluminium alloys, and magnesium alloys.
Stainless steels, nickel based super-alloys, and titanium are forged especially
for aerospace.
Forged automobile components include connecting rods, crankshafts, wheel
spindles, axle beams, pistons, gears, and steering arms.

43
Upsetting (Forging)
Upsetting of metals is a formation process in which a (usually round) billet
is compressed between two dies in a press or a hammer.
This operation reduces the height of a part while increasing its diameter.

44

45
Wire Drawing
Wire drawing involves reducing the diameter of a rod or wire by passing
through a series of drawing dies or plates.
The subsequent drawing die must have smaller bore diameter than the
previous drawing die.
Wires produced by cold drawing through dies.

46
Wire Drawing
Drawing operations involve pulling metal through a die by means of a
tensile force applied to the exit sideof the die
The plastic flow is caused by compression force, arising from the reaction of
the metal with the die
Material should have high ductility and good tensile strength
Bar, wire and tube drawing are usually carried out at room temperature,
except for large deformation, which leads to considerable rise in
temperature during drawing.

47
Wire Drawing
Advantages
Close dimensional control
Good surface finish
Improved strength and hardness
Adaptability to mass production

48
<Video>

49
Extrusion
A compression process in which the materialis forced to
flow throughan opening to produce a shape with a specific
cross-section
Example squeezing of tooth paste out

50
Extrusion
Hot Extrusion
Involves pre-heating the material above the recrystallization
temperature to increase ductility
Cold Extrusion
Does not pre-heat material; used to produce parts in finished or
near-finished form

Metals
Non-Metals
51
Extrusion

52
Metal Extrusion
Direct Extrusion A ram compresses the material, forcing it
through the die
Indirect Extrusion The die is mounted on the ram; the
material is forced outin the opposite direction of the ram
movement
Direct Indirect
Indirect

53
Direct Extrusion

54
Indirect Extrusion
To produce solid cross section
To produce hollow cross section

55
Friction in Extrusion Process
Direct Extrusion Friction with the chamber opposes
forward motion of the billet.
Indirect Extrusion There is no friction, since there is no
relative motion.

56
Friction in Extrusion Process

57
Lead200-250°C
Aluminumanditsalloys375-475°C
Copperanditsalloys650-975°C
Steels875-1300°C
Refractoryalloys975-2200°C
Extrusion Temperature Ranges
Extrusion

58
Sheet Metal Forming
Sheet metal forming is a grouping of many complementary
processes that are used to form sheet metal parts.

59
Shearing operations
Sheet metal cutting operationalong a straight line between
two cutting edges
Typically used to cut large sheets
Front View Side View

60
Shearing operations
Shearing –mechanical cutting of material without the
formation of chipsor the use of burning or melting
Curved blades may be used to produce different shapes
Blanking
Piercing
Notching
Trimming

61
Shearing operations
Shearing –mechanical cutting of material without the
formation of chips
The workpiece is stressed beyondits ultimate strength.
The stresses caused in the metal by the applied forces will
be shearing stresses.

62
Shearing operations
Shearing operation includes
Piercing
Blanking
Notching
Slitting
Parting
Shaving
Trimming

63
Shearing Operations
Punching
It is a cutting operation by which various shaped holes are made in
sheet metal.
Hole is desired product.
Blanking
It is the operation of cutting a flat shape sheet metal.
The article punched out is called the blank.

64
Punching
Punching
1/3of material is cut and 2/3of material fractures

65
Blanking
For thicker and softer materials generally higher angular clearance is
given. In most cases, 2°of angular clearance is sufficient.
Blanking

66
Clearance
To small less than optimal fracture and excessive forces
To large oversized burr
Shearing Operations

67
Trimming
When parts are produced by die casting or drop forging, a small
amount of extra metal gets spread out at the parting plane.
This extra metal, called flash, is cut off before the part is used, by
an operation called trimming.

68
Stretch Forming
Tensile force is applied on the metal which is placed over the die
Large deformation for ductile metal can be achieved only by this process
Sheet is first wrapped around the block and the tensile load is increased
through jaws until sheet is plastically deformed to final shape

69
Itisaoperationbywhichstraightlengthisconvertedto
curvedlikedrums,channels.(Strainingofthemetalarounda
straightaxis)
Bending
(a) Bending of sheet metal; (b) both compression and tensile elongation of the metal occur in bending.

70
Duringthebending:themetalontheinsideoftheneutral
planeiscompressed,whilethemetalontheoutsideis
stretched.
Themetalisplasticallydeformedsothatthebendtakesa
permanentsetuponremovalofthestressesthatcausedit.
Bendingproduceslittleornochangeinthethicknessofthe
sheetmetal.
Bending

71
Bending
Bendingoperationsareperformedusingpunchanddie
tooling.
Types:
V-bending,performedwithaV-die
Edge-bending,performedwithawipingdie
Bending methods: (a) V-bending and (b) edge-bending; (1) before and (2) after bending. v= motion,
F= applied bending force, F
h= blank.

72
Bending force
BendingForceForcerequiredtoperformbendingoperation
Factors
Geometryofthepunchanddie
Strength,thickness,andlengthofthesheetmetalD
wtTSK
F
bf
2
)(

where F= bending force, N
(TS) = tensile strength of the sheet metal, MPa
w= width of part in the direction of the bend axis, mm
t= stock thickness, mm
D= die opening dimension, mm
(a) V-die, (b) wiping die.
V-bending, K
bf= 1.33;
Edge bending, K
bf= 0.33.

73
Springback Bending

74
Springback Bending
SpringbackeffectInbending,afterplasticdeformationthere
isanelasticrecoverythisrecoveryiscalledspringback.
Lowcarbonsteelsspringbackis1–2°,whileformedium
carbonsteelitis3–4°
Compensationforspringback
Overbendingofpart
Bottomingandironing
Allowancesindieandpunch

75
Tube Forming or Bending
Tubeformingrequirespecialtoolingtoavoidbucklingand
folding.
Theoldestmethodofbendingatubeorpipeistopackthe
insidewithlooseparticles,commonlyusedsandandbendthe
partinasuitablefixture.
Thistechniquepreventsthetubefrombuckling.Afterthetube
hasbeenbent,thesandisshakenout.Tubescanalsobe
pluggedwithvariousflexibleinternalmandrels.
<Buckling>

76
Tube Forming or Bending

77
Bend allowance or Bend length
It is the length of the neutral axis in the bend

78
Bend allowance or Bend length (Example)
A 20 mm wide and 4 mm thick C 20 steel sheet is required to be bent at 60
0
at
bend radius 10 mm. Determine the bend allowance.
R = 10 mm;
bend = 60
0
= 60 * (π/180) radians
t = 4 mm;
2t = 8 mm;
Therefore, k = ½
L
b= 60 * (π/180) * (10+0.5*4) = 12.56 mm

79
Bending force
BendingForce
where F= bending force, N
(TS) = tensile strength of the sheet metal, MPa
L= bend allowance or bend length, mm
t= stock thickness, mm
D= die opening dimension, mm
(a) V-die, (b) wiping die.
V-bending, K
bf= 1.3;
Edge bending, K
bf= 0.3.
V-die bending, die opening dimension = D, mm
Wiping die, die opening dimension = D = R + t + R, mmD
LtTSK
F
bf
2
)(


80
Bending force (Example 1)
A400mmlongand2.5mmthickpieceofcarbonsteelsheetisrequiredto
bebentat90
0
usingaV–die.Youmayassumetheyieldstressofthe
materialas500MPaandthedieopeningas10timesthematerial
thickness.Estimatetheforcerequiredfortheoperation.D
LtTSK
F
bf
2
)(

where F= bending force, N
(TS) = tensile strength of the sheet metal, Mpa= 500 MPa
L = bend allowance or bend length, mm = 400 mm
t = stock thickness, mm = 2.5 mm
D= die opening dimension, mm = 10 * 2.5 = 25 mm
V-bending, K
bf= 1.3;
Bending force = F = (1.3 * 500 * 400 * (2.5)
2
)/ 25 = 65 KN

81
Bending force (Example 2)
A400mmlongand2.5mmthickpieceofcarbonsteelsheetisrequiredto
bebentat90
0
usingaV–die.Youmayassumetheyieldstressofthe
materialas500MPaandthedieopeningas10timesthematerial
thickness.Estimatetheforcerequiredfortheoperation.Ifthematerialas
mentionedintheaboveexampleistobebentat90
0
usingwipingdiewith
radius=3.75mm,whatistheforcerequirement?D
LtTSK
F
bf
2
)(

where F= bending force, N
(TS) = tensile strength of the sheet metal, Mpa= 500 MPa
L = bend allowance or bend length, mm = 400 mm
t = stock thickness, mm = 2.5 mm
D= die opening dimension, mm = R + R + t = 3.75 + 3.75 + 2.5 = 10 mm
Edge bending, K
bf= 0.3;
Bending force = F = (0.3 * 500 * 400 * (2.5)
2
)/ 10 = 37.5 KN

82
Asheet-metalpart3mmthickand20mmlongisbenttoanincluded
angleof60
0
andabendradiusof7.5mminaV-die.Thedieopeningis15
mm.themetalhastensilestrengthof340MPa.Computetherequired
forcetobendthepart.
Bending force (Example 3)D
LtTSK
F
bf
2
)(

where F= bending force, N
(TS) = tensile strength of the sheet metal, Mpa= 340 MPa
L = bend allowance or bend length, mm = 20 mm
t = stock thickness, mm = 3 mm
D= die opening dimension, mm = 15
V-bending, K
bf= 1.3;
Bending force = F = (1.3 * 340 * 20 * (3)
2
)/ 15 = 5304 N

83
Example
Acertainsheetmetal(tensilestrength=300MPa),havingathicknessof3
mmandwidth40mmissubjectedtobendinginav-diewithopeningof
22mm.Theotherdimensionsareasshowninfigure.Whataretheblank
sizeandbendingforcerequired?Ignorespringback.

84
Example
Bendangle=60degree
Thelengthoftheblankcanbedeterminedas:L=40+30+Bendallowance
Bendallowance=L
b=6.8mm
Therefore,L=76.8mm
Bendingforce=12535.85ND
LtTSK
F
bf
2
)(


85
Coining
Coiningisacloseddieforgingprocess,inwhichpressureis
appliedonthesurfaceoftheforginginordertoobtaincloser
tolerances,smoothersurfacesandeliminatedraft.
Closeddieforgingisaprocessinwhichforgingisdoneby
placingtheworkpiecebetweentwoshapeddies.
The pressure involved in coining process is about 1600Mpa.

86
Embossing
EmbossingSimilarlikecoining,however,embossingdies
possessmatchingcavitycontours.
Thepunchcontainingthepositivecontour
Thediescontainingthenegativecontour
Whereascoiningdiesmayhavequitedifferentcavitiesinthetwodie
halves
Theoperationisalsosometimesusedformakingdecorationitemslike
numberplatesornameplates,jewelry,etc.

87
<Coining> <Embossing>

88
Formingofsheetintoconvexorconcaveshapes
Sheetmetalblankispositionedoverdiecavityandthanpunch
pushedmetalintoopening.
Theprocessisconsidered"deep"drawingwhenthedepthof
thedrawnpartexceedsitsdiameter.
Exampleproducts:beveragecans,automobilebodyparts,
kitchenutensils
Deep Drawing

89
Deep Drawing

90
Deep Drawing

91
Drawing (Blank size and force calculation)
Drawing

92
Deep Drawing
Drawing Clearance
In drawing sides of punch and die separated by a clearance ‘C’
C = 1.1 T
where, T = stock thickness
Drawing ratio
Ratio between diameter of blank to diameter of punch
D
R= (D
b/D
p) ≤ 2
Drawing reduction ratio
R = ((D
b –D
p)/D
p)≤ 0.5

93
Deep Drawing
Drawing thickness to diameter ratio
D
T/D= T/D
b≥ 1%
Drawing force
The force required for the drawing operation
D
F= πD
p(TS) T (D
R–0.7)
Holding force
F
h= 0.015 S
yπ[ D
p
2
–(D
p+ 2.2t + 2 r
p)
2
]

94
Drawing -Blank size calculation
ThesizeorDiameteroftheblankisgivenby
Blankvolume=Finalproductvolume
D=(d
1
2
+4d
2h)
0.5
Example:122mm
d
1
d
2
h

95
Drawing force calculation

96

97
Types of Die
Progressive die
Compound die
Combination die

98
Progressive die
Progressive die performs two or more operation
simultaneously in a single stroke of punch press.
Multiple station
<washer>
Piercing and blanking at different station

99
Progressive die <Video>

100
Compound die
All the operations are carried out at a single station in single
stroke of ram.
Piercing and blanking at same station
<Video>

101
Combination die
In these types of dies cutting operation is combined with a
non-cutting operation.
The cutting operations may include blanking, piercing,
trimming, etc. and are combined with non-cutting operations
like bending, extruding, forming etc.

•www.google.co.in
•www.researchgate.net
•www.youtube.com
•MikellP. Groover“Fundamentals of Modern Manufacturing Materials, Proc
esses, and Systems”,4
th
Edition,JOHNWILEY & SONS, INC.2010
•E.PaulDeGarmo, Black J.T and Ronald A. Kosher “Materials and Process
es, in Manufacturing”,EightEdition, Prentice –Hall of India, 1997
•James S Campbell “Principles of manufacturing materials and processes”
New Delhi : Tata McGraw-Hill ,1983
•SeropeKalpakjian,Steven R Schmid“Manufacturing Engineering and Tec
hnology” Pearson India, 4th Edition
102
Bibliography

103

Manufacturing
Technology
15ME202
Unit III-Theory of
Metal Cutting
Dr. ManidiptoMukherjee
Research Asst. Professor
Room ME-C 206
Mechanical Engg. Dept.
SRM University
Email. [email protected]/
[email protected]
Mob: 9831349152
Dr. S. Murali
Assistant Professor
Room ME-C 205
Mechanical Engg. Dept.
SRM University
Email. [email protected] /
[email protected]

2

3
Metal Cutting
What is unique in this process?

4
Mechanics of Metal Cutting
A cutting tool exerts compressive force on the workpiece which
stresses the work material beyond the yield point and therefore
metal deform plastically and shears off.

5
Mechanics of Metal Cutting
Plastic flow takes place in a localized region called the shear
plane.
Sheared material begins to flow along the cutting tool face in
the form of chips.
Applied compressive force is cutting force

6
Metal Cutting
What is required for machining?
Depth of cut pre-set interference between tool and work
piece
Feed motion to bring in additional material for machining
Speed what generates the basic wedge and cuts

7
Metal Cutting
Turning

8
Metal Cutting
Drilling

9
Metal Cutting
Milling

10
Metal Cutting
Machining requirements
Theblankandthecuttingtoolareproperlymounted(infixtures)andmovedina
powerfuldevicecalledmachinetoolenablinggradualremovaloflayerofmaterialfrom
theworksurfaceresultinginitsdesireddimensionsandsurfacefinish.Additionally
someenvironmentcalledcuttingfluidisgenerallyusedtoeasemachiningbycooling
andlubrication.

11
Machine Tools
Machine tool It is a power operated device or system of
devices in which energy is expended to produce jobs of desired
size, shape and surface finish by removing excess material from
the preformed blanksin the form of chipswith the help of
cutting tools moved past the work surface's.

12
Machine Tools
Physical function of a machine tool
Firmly holding the blank and the tool
Transmit motions to the tool and the blank
Provide power to the tool-work pair for the machining action
Control of the machining parameters (speed, feed and depth
of cut).

13
Theory of Metal Cutting
Metal cutting is the process of producing a work piece by
removing unwanted material from a block of metal, in the form
of chips.

14
Rake Angle

15

16

17

18
Orthogonal and Oblique Cutting (Cutting Edge)
Orthogonal cutting the cutting edge of the tool is straight
and perpendicularto the direction of motion.
Oblique cutting The cutting edge of the tools is set at an
angleto the direction of motion.

19
Orthogonal and Oblique Cutting (Chip flow)
Orthogonal cutting The directionof the chip flow velocity is
normal to the cutting edge of the tool
Oblique cutting The direction of the chip flow velocity is at an
angle with the normal to the cutting edge of the tool. The angle
is called as chip flow angle.

20
Orthogonal and Oblique Cutting (dimension)
Orthogonal cutting Cutting force and thrust force are acting.
It can be considered as two dimensional cutting.
Oblique cutting Cutting force, radial force and thrust force or
feed force are acting. So the metal cutting may be considered as
a three dimensional cutting.

21
Fc Cutting Force; Ft Thrust Force

22
Orthogonal and Oblique Cutting (heat flow)
Orthogonal cutting During metal cutting process, the heat
developed due to friction per unit area is more.
Oblique cutting The heat developed due to friction per unit
area is less.

23
Orthogonal and Oblique Cutting (tool life)
Orthogonal cutting Smaller when compared to Oblique
cutting for same cutting condition.
Oblique cutting Tool have longer life compared to orthogonal
cutting.

24
Orthogonal and Oblique Cutting (shear force)
Orthogonal cutting Shear force act on a small area.
Oblique cutting Shear force act on a larger area.

25
Cutting tools classification
Cutting Tools classification
Single point cutting edge tool
Multiple point cutting edge tool

26
Single point cutting edge tool
Single point cutting edge tool
One dominant cutting edge
Point is usually rounded to form a nose radius
Turning uses single point tools

27
Single point cutting edge tool
Single point cutting edge tool
These tools may be left-handed or right-handed
Example: Right handed / Left handed

28
Single point cutting edge tool
Single point cutting edge tool
These tools may be left-handed or right-handed
It depends on the cutting edge position

29
Single point cutting edge tool
Single point cutting edge tool
Solid type and the tipped tool

30
Multiple point cutting edge tool
Multiple point cutting edge tool
More than one cutting edge
Motion relative to work achieved by rotating
Drilling and milling use rotating multiple cutting edge tools

31

32
Tool signature for single point cutting tool
Flank

33
Tool signature for single point cutting tool
Shank
It is the main body of the tool
Flank
The surface of the tool adjacent to the cutting edge
Face
The surface on which the chip slides
Nose
It is the point where the side cutting edge and end cutting edge intersect

34
Tool signature for single point cutting tool
Nose radius
Strengthens finishing point of tool
Cutting edge
It is the edge on the face of the tool which removes the material from the
work piece

35
Tool signature for single point cutting tool
Side cutting edge angle
Angle between side cutting edge and the side of the tool shank
End cutting edge angle
Angle between end cutting edge and the line normal to the tool shank

36
Tool signature for single point cutting tool
Side relief angle
Angle between the portion of the side flank immediately below the side
cutting edge and a line perpendicular to the base of the tool, measured
at right angle to the side flank

37
Tool signature for single point cutting tool
End relief angle
Angle between the portion of the end flank immediately
below the end cutting edge and a line perpendicular to the
base of the tool, measured at right angle to the end flank

38
Tool signature for single point cutting tool
Side rake angle
Angle between the tool face and a line parallel to the base of
the tool and measured in a plane perpendicular to the base
and the side cutting edge
Back rake angle
Angle between the tool face and a line parallel to the base of
the tool and measured in a plane perpendicular to the side
cutting edge

39
Single point cutting tool

40
Machine Reference System or ASA

41
Orthogonal Rake system (ORS)

42
Auxiliary Orthogonal Clearance Angle

43
Tool signature for single point cutting tool
Convenient way to specify tool angles by use of a standardized
abbreviated system is known as tool signature or tool
nomenclature.
Tool signature (7 elements)
1. Back rake angle (0°)
2. Side rake angle (7°)
3. End relief angle (6°)
4. Side relief angle (8°)
5. End cutting edge angle (15°)
6. Side cutting edge angle (16°)
7. Nose radius (0.8 mm)

44

45
Cutting Tool Materials
Materials
Carbon steels, High-speed steels
Cast carbides, Cemented carbides, Coated carbides
Cermets, Ceramic tools
Polycrystalline cubic boron nitride
Polycrystalline diamond

46
Cutting Tool Materials
Properties
Red hardness or hot hardness It is the ability of a material
to retain its hardness at high temperature
Wear resistance It enables the cutting tool to retain its
shape and cutting efficiency
Toughness It relates to the ability of a material to resist
shock or impact loads associated with interrupted cuts.
High thermal shock resistance
Low adhesion to work piece material
Low diffusivity to work piece material

47
Types of Chips
Discontinuous chips
Continuous chips
Continuous chips with built-up edge
Serrated chip or Non-homogenous chip

48
Types of Chips
Discontinuous chips
When brittle materials like cast iron are cut, the deformed
material gets fractured very easily and thus the chip
produced is in the form of discontinuous segments
Reasons
Brittle work materials
Low cutting speeds
Large feed and depth of cut
High tool-chip friction

49
Types of Chips
Continuous chips
Continuous chips are normally produced when machining
steel or ductile materials at high cutting speeds. The
continuous chip which is like a ribbon flow along the rake
face.
Reasons
Ductile work materials
High cutting speeds
Small feeds and depths
Sharp cutting edge
Low tool-chip friction

50
Types of Chips
Continuous chips with build-up edge (BUE)
Whenthefrictionbetweentoolandchipishighwhilemachiningductile
materials,someparticlesofchipadheretothetoolrakefacenearthe
tooltip.Whensuchsizeablematerialpilesupontherakeface,itactsasa
cuttingedgeinplaceoftheactualcuttingedgeistermedasbuiltup
edge(BUE).Byvirtueofworkhardening,BUEisharderthantheparent
workmaterial
Reasons
Tools-chipsfrictioncausesportionsofchiptoadhereto
rakeface
BUEforms,thenbreaksoff,cyclically
Low-to-mediumcuttingspeeds
Ductilematerials

51
Types of Chips
Serrated chips or Non-homogenous chip
Semicontinuous(sawtoothappearance)chips
Associatedwithdifficult-to-machinemetalsathighcuttingspeeds
Reasons
Ductilematerials
Low-to-mediumcuttingspeeds
Tool-chipfrictioncausesportionsofchiptoadheretorakeface
BUEforms,thenbreaksoff,cyclically

52
Chip breakers
Long continuous chip are undesirable (safety issue)
Chip breaker is a piece of metals clamped to the rake surface of
the tool which bends the chip and breaks it
Chips can also be broken by changing the tool geometry,
thereby controlling the chip flow

53
Machinability
Machinability is a system property that indicates how easy a
material can be machined at low cost.
Good machinability cutting with minimum energy, minimum
tool wear, good surface finish.

54
Machinability
Quantitative measures of machinability
Machinability index
Tool life
Surface finish

55
Machinability
Good machinablematerials should have
Low ductility
Low shear strength
Low hardness
High thermal conductivity
Weak metallurgical bond (adhesion)

56
Machinability
Machinable materials
Ferrous materials
Carbon steels : annealed, heat-treated, cold worked
Alloy steels: hard
Stainless steels
Cast iron
Non-ferrous materials
Zinc, magnesium, aluminium alloys, beryllium, titanium

57
Cutting fluids
Cutting fluids used to reduce friction and tool wear
Function of cutting fluids
Lubrication
Cooling
Chip removal
Types
Straight oil (petroleum based oils), Soluble oil (water
based oils), animal fats, plant oils
Characteristics
Good cooling and lubricating qualities, rust resistance,
nontoxic, transparent, non-flammable

58
Cutting fluids
Economic advantages of using cutting fluids
Reduction of tool costs
Reduce tool wear, tools last longer
Increased speed of production
Reduce heat and friction so higher cutting speeds
Reduced of labor costs
Tools last longer and require less regrinding, less
downtime, reducing cost per part
Reduction of power costs
Friction reduced so less power required by machining

59
Mechanism of Cutting
Cutting action involves shear deformation of work material to
form a chip. As chip is removed, new surface is exposed.

60
Mechanism of Cutting
Mechanism of Orthogonal Cutting
Orthogonal cutting assumes that the cutting edgeof the tool
is set in a position that is perpendicularto the direction of
relative work or tool motion.

61
Mechanism of Cutting

62
In turning, w = depth of cut and t
1= feed
Mechanism of Cutting

63
Mechanism of Cutting (Cutting ratio)

64
Mechanism of Cutting (Shear Plane Angle)

65
Mechanism of Cutting (Shear Plane Angle)
Shear Plane Angle Derivation

66
Mechanism of Cutting (Shear Strain)

67
Mechanism of Cutting (Shear Strain)

68
Mechanism of Cutting (Shear Strain)

69
Mechanism of Cutting (Cutting Forces)
Cutting force in conventional turning operation

70
Mechanism of Cutting (Cutting Forces)

71
Mechanism of Cutting (Cutting Forces)
ThelargestmagnitudeistheverticalforceF
cwhichinturningis
largerthanfeedforceF
f,andF
fislargerthanradialforceF
r.
FororthogonalcuttingsystemF
rismadezerobyplacingthe
faceofcuttingtoolat90°tothelineofactionofthetool.

72
Tool Failure
Processofcuttingtoolfailure
Types
Byplasticdeformation
Bychippingduetomechanicalbreakage
Burningofthetool
Bygradualwear

73
Tool Failure

74
Tool Wear

75
Tool Wear
Toolsgetwornoutduetolongtermusageorgradualfailureofcutting
toolsduetoregularoperation.
Types
Flankwear
Itoccursontherelieffaceofthetoolandthesidereliefangle.
Craterwear
Itoccursontherakefaceofthetool.
Notchwearorchipping
Breakingawayofasmallpiecefromthecuttingedgeofthetool

76
Tool Wear

77
Tool Wear

78
Tool Wear
cuttingconditions(cuttingspeedV,feedf,depthofcutd)
cuttingtoolgeometry(toolorthogonalrakeangle)
propertiesofworkmaterial
VB Flank wear land
VBktool life

79
Tool Wear

80
Tool Life Expectancy Equation
V –Cutting speed
T –Tool life
C –Machining Constant
??????
????????????
??????
&#3627408439;
&#3627408485;
??????
&#3627408486;
=&#3627408438;
Taylor’s Equation

81
Tool Life Expectancy Equation
1.While machining carbon steel by a tungsten based steel tool, tool life of 50
minutes was observed when machined with a cutting speed of 100 m/min.
Determine(a) General Taylor’s tool life equation and (b) tool life for a cutting
speed of 80 m/min. Assume n = 0.09.

82
2. A carbide-cutting tool when machined with mild steel workpiece material at a cutting
speed of 50m/min lasted for 100 minutes. Determine the life of the tool when the
cutting speed is increased by 25%. At what speed the tool is to be used to get a tool
life of 180 minute. Assume n = 0.26 in the Taylor’s expression.
Tool Life Expectancy Equation

83
Forces acting on chip

84
Forces acting on chip

85
Resultant forces

86
Shear Stress

87
Shear angle and its significance

88
Force calculations

89
Force calculations

90
Force calculations

91
Velocity calculations

92
Merchant Circle Diagram https://www.youtube.com/watch?v=YCLZMx_nhsM#

93
Merchant Circle Diagram
Merchantcirclediagramisusedtoanalyzetheforcesactinginmetalcutting
Theanalysisofthreeforcessystem,whichbalanceeachotherforcuttingto
occur.Eachsystemisatriangleofforces.
Thethreetrianglesofforcesinmerchant’scirclediagramare
1.Atriangleofforcesforthecuttingforces,
2.Atriangleofforcesfortheshearforces,
3.Atriangleofforcesforthefrictionalforces.
Three angles: rake, shear and friction

94
Merchant Circle Diagram

95
Merchant Circle Diagram
AssumptionsmadeindrawingMerchant’scircle:
Shearsurfaceisaplaneextendingupwardsfromthecuttingedge.
Thetoolisperfectlysharpandthereisnocontactalongtheclearanceforce.
Thecuttingedgeisastraightlineextendingperpendiculartothedirectionof
motionandgeneratesaplanesurfaceastheworkmovespastit.
Thechipdoesn’tflowtoeitherside,thatischipwidthisconstant.
Thedepthofcutremainsconstant.
Widthofthetoo,isgreaterthanthatofthework.
Workmoveswithuniformvelocityrelativetooltip.
Nobuiltupedgeisformed.

•www.google.co.in
•www.researchgate.net
•www.youtube.com
•https://onlinecourses.nptel.ac.in/
•MikellP. Groover“Fundamentals of Modern Manufacturing Materials, Proc
esses, and Systems”,4
th
Edition,JOHNWILEY & SONS, INC.2010
•E.PaulDeGarmo, Black J.T and Ronald A. Kosher “Materials and Process
es, in Manufacturing”,EightEdition, Prentice –Hall of India, 1997
•James S Campbell “Principles of manufacturing materials and processes”
New Delhi : Tata McGraw-Hill ,1983
•SeropeKalpakjian,Steven R Schmid“Manufacturing Engineering and Tec
hnology” Pearson India, 4th Edition
96
Bibliography

97

Manufacturing
Technology
15ME202
Unit IV-Gear
Manufacturing and
Surface Finishing
Dr. ManidiptoMukherjee
Research Asst. Professor
Room ME-C 206
Mechanical Engg. Dept.
SRM University
Email. [email protected]/
[email protected]
Mob: 9831349152
Dr. S. Murali
Assistant Professor
Room ME-C 205
Mechanical Engg. Dept.
SRM University
Email. [email protected] /
[email protected]

2

3
Gear
A gear is rotating machine part having cut teeth, which mesh
with another toothed part in order to transmit torque.
Two or more gears working in tandem are called a transmission.
Geared devices can change the speed, magnitude, and direction
of a power source.

4
Gear
The most common situation is for a gear to mesh with another
gear; howevera gear can also mesh a non-rotating toothed part,
called arack, thereby producing translation instead of rotation.

5
Gear
Gears are used extensively for transmission of power.
Application automobiles, gear boxes, oil engines, machine
tools, etc.

6
Gear Materials
Gear Materials wide variety of cast irons, non ferrous materials
Selection of gear materials
Purpose (type of service), peripheral speed, degree of
accuracy, method of manufacture, allowable stress, shock
resistance, wear resistance

7
Gear Manufacturing Process
Gear manufacturing divided into forming and machining

8
Sintering Process

9
Sintering Process

10
Sintering Process

11
Sintering
Sinteringis a heat treatment applied to a powder compact in
order to impart strength and integrity.
The temperature used forsinteringis below the melting point of
the major constituent of the Powder Metallurgy material.

12
Sintering

13
Sintering

14
Sintering
Sintered gear characteristics
Accuracy similar to die cast gears
Material properties can be tailor made
Typically suited for small size gears
Economical for large lot size only
Secondary machining is not required

15
Extrusion
Material is drawn through a die, giving the material a new cross-
sectional shape that is usually constant throughout the lengths of
the material.

16
Extrusion
Extrusion process is used to form teeth on long rods, which are
then cut into usable lengths and machined for bores and keyways
etc.
Nonferrous materials Copper and aluminium alloys are
commonly extruded rather than steels.
Suitable for mass production, also small sized gear.
Example: watches, clocks, type writers, etc.,

17
Stamping
Sheet metal can be stamped with tooth shapes to form low
precision gears at low cost in high quantities.
Surface finish and accuracy are poor.
Example toy gears, clock gears, watch gears, etc.,

18
Stamping
After stamping, the gears are shaved, they give best finish and
accuracy.
The materials which can be stamped are : low, medium, and high
carbon steels, stainless steel.
Mass production possible.

19
Gear Machining or Generating Process
Roughing processes include milling the tooth shape with formed
cutters or generating the shape with a rack cutter, shaping cutter
or a hob cutter.
The roughing processes actually produce a smooth and accurate
gear tooth. If high precision and quiet running demands, the
secondary finishing operation is justified at added cost.

20
Gear Shaping
It uses a cutting tool in the shape of a gear which is reciprocated axially across the gear
blank to cut the teeth while the blank rotates around the shaper tool.
It is true shape generation process in that the gear shaped tool cuts itself into mesh
with the gear blank.

21
Gear Shaping
Gear shaping by disc cutter
The disc cutter shape confirms the gear tooth shape. Each gear needs
separate cutter. However, with 8 to 10 std. cutters, gears from 121 to 120
teeth can be cut with fair accuracy. Tooth is cut one by one by plunging
the rotating cutter in to the blank.

22
Gear Shaping
Gear shaping by End Mill Cutter
The End mill cutter shape confirms the gear tooth shape. Each tooth is cut
at time and then indexed for next Tooth space for cutting. A set of 10
cutters will do for 12 to 120 teeth gears. Suited for small volume
production of low precision gears.

23
Gear Shaping
Gear shaping by Rack –type cutter
generating cutter has the form of a basic rack.
The cutter reciprocates rapidly & removes metal only during the cutting
stroke.
The blank is rotated slowly but uniformly about its axis and between each
cutting stroke of the cutter, the cutter advances along its length at a speed
equal to the rolling speed of the matching pitch lines.

24
Gear Shaping
Spur Gear Generation by Rack –type cutter

25
Gear Shaping

26
Gear Shaping
Gear shaping by Pinion type cutter
The pinion cutter generating process is fundamentally the same as the rack
cutter generating process, and instead of using a rack cutter, it uses a
pinion to generate the tooth profile.

27
Gear Hobbing
Hobbing is the process of generating gear teeth by means of a
rotating cutter called a hob.
It is a continues indexing process in which both the cutting tool &
work piece rotate in a constant relationship while the hob is being
fed into work.

28
Gear Hobbing
The teeth of hob cut into the work piece in successive order &
each in a slightly different position.
Each hob tooth cuts its own profile depending on the shape of
cutter.
One rotation of the work completes the cutting up to certain
depth.

29
Gear Hobbing
It is the most accurate machining process since no repositioning
of tool or blank is required and each tooth is cut by multiple hop
teeth averaging out any tool errors.

30
Gear Hobbing Types
Axial Hobbing ( Axis of Hobberand blank are parallel)

31
Gear Hobbing Types
Radial Hobbing ( Axis of Hobberand blank are Perpendicular)

32
Gear Hobbing Types
Tangential Hobbing ( Axis of Hobberand blank are Tangential)

33
Grinding Process (Surface Finishing Process)
Grinding is the abrasive machining process.
Cutting mode gritor grains of abrasive material
These grits are characterized by sharp cutting points, high hot hardness, chemical
stability and wear resistance.
Bonding material used to held together the grits.

34
Applications
Surface finishing
Slitting
De-scaling , De-burring
Grinding of tools and cutters and re-sharpening of the same.
Grinding Process (Surface Finishing Process)

35
Grinding Machines machine tools.
Machine tool It is a power operated device or system of devices in which energy
is expended to produce jobs of desired size, shape and surface finish by removing
excess material from the preformed blanksin the form of chipswith the help of
cutting tools moved past the work surface's.
Grinding Machine

36
Grinding Machines machine tools.
Feature of grinding machines rotating abrasive tool.
Grinding machine is employed to obtain high accuracy along with very high class
of surface finishon the work piece.
Conventional grinding machines can be broadly classified as:
Surface grinding machine
Cylindrical grinding machine
Center less grinding
Grinding Machine

37
In surface grinding, the spindle position is either horizontal or vertical, and the
relative motion of the work piece is achieved either by reciprocating the work piece
past the wheel or by rotatingit. The possible combinations of spindle orientations
and work piece motionsyield four types of surface grinding processes illustrated in
the figure.
Surface grinding machine

38
Surface grinding machine

39
Surface grinding machine
<Horizontal Grinding Machine> <Vertical Grinding Machine>
A: rotation of grinding wheel
B: reciprocation of worktable
C: transverse feed
D: down feed

40
External or internal cylindrical grinding
External cylindrical grinding (center-type grinding) the work piece rotates and reciprocates along
its axis, although for large and long work parts the grinding wheel reciprocates.
Internal cylindrical grinding, a small wheel grinds the inside diameter of the part. The work
piece is held in a rotating chuck in the headstock and the wheel rotates at very high rotational
speed. In this operation, the work piece rotates and the grinding wheel reciprocates.
Cylindrical grinding

41
Cylindrical grinding machine (External)
A: rotation of grinding wheel
B: work table rotation
C: reciprocation of worktable
D: infeed
The surface may be straight, tapered, grooved or profiled.

42
Cylindrical grinding machine (Internal)
The surface may be straight, tapered, grooved or profiled.

43
Centre less grinding

44
Centre less grinding
Center less grinding is a process for continuously grinding cylindrical surfaces in
which the work piece is supported not by centersor chucks but by a rest blade.
The work piece is ground between two wheels.
The larger grinding wheel does grinding, while the smaller regulating wheel, which
is tilted at an angle i, regulates the velocity Vfof the axial movement of the work
piece.
Center less grinding can also be external or internal, traverse feed or plunge
grinding. The most common type of center less grinding is the external traverse
feed grinding.

45
Grinding Wheel
Grinding wheel consists of hard abrasive grains called grits, which perform
the cutting or material removal, held in the weak bonding matrix.
A grinding wheel commonly identified by the type of the abrasive material
used.
The conventional wheels include aluminium oxide and silicon carbide
wheels while diamond and CBN (cubic boron nitride) wheels fall in the
category of super abrasivewheel.

46
Grinding Wheel
Specification of grinding wheel
Geometrical specification
This is decided by the type of grinding machine and the grinding
operation to be performed in the workpiece.
This specification mainly includes wheel diameter, width and depth of rim
and the bore diameter.
Compositional specification

47
Grinding Wheel
Specification of grinding wheel
Compositional specification
type of gritmaterial
grit size
bond strength of the wheel, commonly known as wheel hardness
The structure of the wheel denoting the porosity i.e. the amount of
inter grit spacing
type of bond material

48
Grinding Wheel
Conventional abrasive grinding wheels

49
Grinding Wheel
Super abrasive grinding wheels
The bonding materials for the super abrasives are (a), (d), and (e) resinoid, metal, or vitrified, (b) metal,
(c) vitrified, and (f) resinoid.

50
Grinding Wheel
Examples of Bonded Abrasives
Conventional abrasives
Al
2O
3for High-tensile strength materials
SiCfor low-tensile strength materials
Super abrasives
Cubic boron nitride (CBN)
Diamond

51
Grinding Wheel
Bonding materials

52
Grinding Wheel

53
Grinding Wheel

54
Grinding Wheel

55
General rules for grinding

56
General rules for grinding

57
General rules for grinding

58
Material to be ground and its hardness.
Amount of stock removal and finish required.
Whether the grinding is done wet or dry.
Wheel speed.
Area of grinding contact.
Severity of the grinding operation.
Selection of Cutting speed and Working speed is based on

59
Grinding Wheel

60
Truing is the process of making grinding wheel round and concentric with its
spindle axis and producing required form of shape on wheel
Involves grinding of a portion of the abrasive section of grinding wheel
Act of regenerating the required geometry on the grinding wheel, whether
the geometry is a special form or flat profile.
This process produces the macro-geometryof the grinding wheel.
A new conventional wheel also requires truing to ensure concentricity
In practice the effective macro-geometry of a grinding wheel is of vital
importance and accuracy of the finished work piece is directly related to
effective wheel geometry.
Truing of Grinding Wheel

61
Truing of Grinding Wheel

62
Dressing of Grinding Wheel
Dressing is the conditioning of the wheel surface which ensures that grit
cutting edges are exposed from the bond and thus able to penetrate into
the work piece material.
Operation of removing dull grains.
Dressing or micro geometry

63
Dressing of Grinding Wheel
Reasons for dressing wheel
Reduce heat generated between work and wheel
Reduce strain on grinding wheel and machine
Improve surface finish and accuracy of work
Increase rate of metal removal

64
Dressing of Grinding Wheel
Truing and dressing are commonly combined into one operation for
conventional abrasive grinding wheels, but are usually two distinctly separate
operation for super abrasive wheel.

65
Finishing operation
The surface finish has a vital role in influencing functional characteristics like
wear resistance, fatigue strength, corrosion resistance and power loss due to
friction.
The finishing operations are assigned as the last operations in the single part
production cycle usually after the conventional or abrasive machining
operations, but also after net shape processes such as powder metallurgy,
cold flash less forging, etc.

66
Finishing operation
Lapping
Buffing
Honing
Super finishing
Wire brushing
Polishing
Electro polishing
Magnetic-field-assisted polishing

67
Lapping
It is a machining operation, in which two surfaces are rubbed together with
an abrasive between them, by hand movements or by a way of a machine.

68
Lapping

69
Lapping

70
Lapping

71
Lapping
Abrasives of lapping
Al
2O
3and SiC, grain size 5~100μm
Cr
2O
3, grain size 1~2 μm
B
4C
3, grain size 5-60 μm
Diamond, grain size 0.5~5 V
Lubricating materials of lapping
Machine oil
Rape oil
grease
Technical parameters affecting lapping processes are
unit pressure
the grain size of abrasive
concentration of abrasive in the vehicle
lapping speed

72
Polishing
Polishing
It is a finishing operation to improve the surface finish by means of a polishing
wheel made of fabrics or leather and rotating at high speed.
The abrasive grains are glued to the outside periphery of the polishing wheel.

73
Buffing
Buffing
It is a finishing operation similar to polishing, in which abrasive grains are not
glued to the wheel but are contained in a buffing compound that is pressed into
the outside surface of the buffing wheel while it rotates. As in polishing, the
abrasive particles must be periodically replenished.
Buffing wheels are made of discs of linen, cotton, broad cloth and canvas

74
Finishing processes that utilize abrasive belts are referred to as polishing, and
processes that use cloth wheels with compound applied is buffing.
Buffing vs polishing

75
Honing is a finishing process performed by a honing tool, which contains a set of
three to a dozen and more bonded abrasive sticks. The sticks are equally spaced
about the peripheryof the honing tool. They are held against the work surface with
controlled light pressure, usually exercised by small springs.
The honing tool is given a complex rotational and oscillatory axial motion, which
combine to produce a crosshatched lay pattern of very low surface roughness
Honing
Honing tool

76
Honing

77
Stone
Al
2O
3or SiCbonded abrasives
The critical process parameters are:
Rotation speed
Oscillation speed
Length and position of the stroke
Honing stick pressure
Parameters that affect material removal rate (MRR) and surface roughness (R) are:
Unit pressure, p
Peripheral honing speed, Vc
Honing time, T
Honing

78
Honing

79
Honing

80
Honing

81
Super Finishing
Super finishing is a micro finishing process that produces a controlled surface
condition on parts which is not obtainable by any other method. The operation
which is also called ‘micro stoning’ consist of scrubbing a stone against a surface to
produce a fine quality metal finish.
The process consists of removing chatter marks and fragmented or smear metal
from the surface of dimensionally finished parts. As much as 0.03 to 0.05 mm of
stock can be efficiently removed with some production applications, the process
becomes most economical if the metal removal is limited to 0.005 mm

82
Super Finishing
Figure Schematic illustrations of the super finishingprocess for a cylindrical part. (a)
Cylindrical mircohoning, (b) Centerless microhoning.

•www.google.co.in
•www.researchgate.net
•www.youtube.com
•https://onlinecourses.nptel.ac.in/
•MikellP. Groover“Fundamentals of Modern Manufacturing Materials, Proc
esses, and Systems”,4
th
Edition,JOHNWILEY & SONS, INC.2010
•E.PaulDeGarmo, Black J.T and Ronald A. Kosher “Materials and Process
es, in Manufacturing”,EightEdition, Prentice –Hall of India, 1997
•James S Campbell “Principles of manufacturing materials and processes”
New Delhi : Tata McGraw-Hill ,1983
•SeropeKalpakjian,Steven R Schmid“Manufacturing Engineering and Tec
hnology” Pearson India, 4th Edition
83
Bibliography

84

Manufacturing
Technology
15ME202
Unit V-Machine
Tools
Dr. ManidiptoMukherjee
Research Asst. Professor
Room ME-C 206
Mechanical Engg. Dept.
SRM University
Email. [email protected]/
[email protected]
Mob: 9831349152
Dr. S. Murali
Assistant Professor
Room ME-C 205
Mechanical Engg. Dept.
SRM University
Email. [email protected] /
[email protected]

2

3
Machine Tools
Machine tool It is a power operated device or system of
devices in which energy is expended to produce jobs of desired
size, shape and surface finish by removing excess material from
the preformed blanksin the form of chipswith the help of
cutting tools moved past the work surface's.

4
Machine Tools
Physical function of a machine tool
Firmly holding the blank and the tool
Transmit motions to the tool and the blank
Provide power to the tool-work pair for the machining action
Control of the machining parameters (speed, feed and depth
of cut).

5
Milling
Milling is the process of machining flat, curved, or irregular surfaces by
feeding the work piece against a rotating cutter containing a number of
cutting edges(i.e., multi point cutting edge tool).
Multi-tooth cutting tool is called a milling cutter and the cutting edges are
called teeth.

6
Milling
Milling is an interrupted cutting operation in which the teeth of the milling
cutter enter and exit the work during each revolution.
This interrupted cutting action subjects the teeth to a cycle of impact force
and thermal shock on every rotation.
The tool material and cutter geometry must be designed to withstand these
conditions.
Cutting fluids are essential for mostmilling operations.

7
Milling Machine
The axis of rotation of the cutting tool is perpendicular to the direction of
feed, either parallel or perpendicular to the machined surface.
Milling machine Machine tool
Basic components
motor driven spindle mounts and revolves the milling cutter
Reciprocating adjustable worktable mounts and feeds the work
piece.
Electric drive motors, coolant systems, variable spindle speed, power-
operated table feeds.

8
Milling Machine Classification
The conventional milling machines provide a primary rotating motion for
the cutterheld in the spindle, and a linear feed motion for the work piece,
which is fastened onto the worktable.
Milling machines for machining of complex shapes usually provide both a
rotating primary motion and a curvilinear feed motion for the cutter in the
spindle with a stationary work piece.

9
Milling Machine Classification
According to nature of purposes of use
General Purpose Milling Machine
Conventional milling machines, e.gUp and down milling machines
Single Purpose Milling Machine
Thread, cam milling machines and slitting machine
Special Purpose Milling Machine
Mass production machines, e.g., duplicating mills, thread milling etc.

10
Milling Machine Classification
According to configuration and motion of the work-holding table / bed
Knee type
Bed type
According to the orientation of the spindle
Horizontal
Vertical
Universal

11
Milling Machine Classification
Column-and-knee milling machine
a column that supports the spindle, and a knee that supports the work
table.
Two types: horizontal and vertical

12
Milling Machine Classification
Bed type milling machine
the worktable is mounted directly on the bed that replaces the knee
greater rigidity, thus permitting heavier cutting conditions and higher
productivity. This machines are designed for mass production

13
Milling Machine Classification
Horizontal Milling Machine Vertical Milling Machine

14
Milling Machine Classification

15
Horizontal Milling Machine
BaseCarries the entire load, should have high
compressive strength (made with cast iron). Act as a
reservoir of cutting fluid.
ColumnAnother foundation. Supports knee,
table, etc. It work as a housing for the all the other
driving member. Contains driving gears and
sometimes motor for the spindle and the table.
Knee first moving part of the milling machine. It
moves along the slide ways, up and down, distance
between the tool and workpiece. Mechanical or
hydraulically driven.
TableMade by cast iron. T-slot cut. Clamping
blots.
Overhanging armSupports arbor
ArborIt is used as extension part of the spindle
in horizontal milling m/c. It holds tool
SaddleBetween table and knee. Can move
transversally to the column face. The main
function to provide motion in horizontal
direction to work piece.
Spindle Main part of the machine. Holds
tool at right place in vertical milling m/c, and
hold arborin horizontal milling m/c.

16
Horizontal Milling Machine

17
Vertical Milling Machine

18
Machining Center
Amachiningcenterisahighlyautomatedmachinetoolcapableofperfo
rmingmultiplemachiningoperationsunderCNCcontrol.
Thefeaturesthatmakeamachiningcenteruniqueincludethefollowing
Toolstorageunitcalledtoolmagazinethatcanholdupto120differentcuttingtools.
Automatictoolchanger,whichisusedtoexchangecuttingtoolsbetweenthetoolmagazine
andmachiningcenterspindlewhenrequired.ThetoolchangeriscontrolledbytheCNCpro
gram.
Automaticworkpartpositioning.Manyofmachiningcentersareequippedwitharotarywo
rktable,whichpreciselypositionthepartatsomeanglerelativetothespindle.Itpermitsthe
cuttertoperformmachiningonfoursidesofthepart.

19
Machining Center

20
Milling Methods
Types of milling methods
Down (climb) milling, when the cutter rotation is in the same direction
as the motion of the work piece being fed.
Up (conventional) milling, in which the work piece is moving towards
the cutter, opposing the cutter direction of rotation

21
Down milling
Down (climb) millingthe cutting force is directed into the work table,
which allows thinner work parts to be machined.
Better surface finish is obtained but the stress load on the teeth is
abrupt(unexpected/sudden), which may damage the cutter.

22
Up milling
Up (conventional) milling the cutting force tends to lift the work piece.
The work conditions for the cutter are more favorable.
The surface has a natural waviness.

23
Up milling
Up (conventional) milling the cutting force tends to lift the work piece.
The work conditions for the cutter are more favorable.
The surface has a natural waviness.

24
Types of milling
Peripheral and face milling
In peripheral milling, also called plain milling, the axis of the cutter is parallel
to the surface being machined, and the operation is performed by cutting
edges on the outside periphery of the cutter.
In face milling, cutter is perpendicular to the machined surface.

25
Peripheral milling
Slitting
Slab milling the cutter width extends beyond the work piece on both sides
Slottingslot milling, width of the cutter usually called slotter, is less than the work
piece width
The slotterhas teeth on the periphery and over the both end faces.
If one-side face teeth are engaged, then operations is known as side milling.
Straddle milling Same as side milling where cutting takes place on both side of the
work (two slotters)
If the slotteris very thin, the operation is called slitting (teeth only on the periphery)

26
Face milling
Cutter is perpendicular to the machined surface.
Machining is performed by teeth on both the end and periphery of the face-
milling cutter.
Face milling is usually applied for rough machining of large surfaces.
Surface finish is worse than in peripheral milling, and feed marks are inevitable.
One advantage of the face milling is the high production rate because the
cutter diameter is large and as a result the material removal rate is high.
Face milling with large diameter cutters requires significant machine power.

27
End milling
Kind of face milling.
End mill has helical cutting edges
To produce pockets, closed or end key slots

28
Milling of complex surfaces
Complex surfaces can be machined either by means of the cutter path (profile milling
and surface contouring), or the cutter shape (form milling)
<Form milling>
<Profile milling>
<surface milling>

29
Milling Cutters
Classification of milling cutter according to their design
HSS cutters: Many cutters like end mills, slitting cutters, slab cutters, angular cutt
ers, form cutters, etc., are made from high-speed steel (HSS).
Brazed cutters: Very limited number of cutters (mainly face mills) are made with
brazed carbide inserts. This design is largely replaced by mechanically attached c
utters.
Mechanically attached cutters: The vast majority of cutters are in this category. C
arbide inserts are either clamped or pin locked to the body of the milling cutter.

30
Milling Cutters
Classification of milling cutter based on milling operation
Surfaces are not related with the tool shape
Slab or plain milling cutter : straight or helical fluted
Side milling cutters –single side or both sided type
Slotting cutter
Slitting or parting tools
End milling cutters –with straight or taper shank
Face milling cutters
Where the job profile becomes the replica of the tool-form
Form cutters, Gear (teeth) milling cutters, Spline shaft cutters, Tool form cutters, T-slot
cutters, Thread milling cutter

31
Milling Cutters
<Machining flat surface by slab milling Cutter>

32
Milling Cutters
<Side milling cutters>

33
Milling Cutters
<Face milling cutters>

34
Milling Cutters
<Gear Milling Cutters>
<T-Slot Milling Cutters>

35
Milling Cutters
<Thread Milling Cutters>

36
Simple Operations Performed in Milling
Reference: Introduction to Basic
Manufacturing Processes and
Workshop Technology, by Rajender
Singh.
Please refer Page: 455-458 for clear
picture and more understanding

37
Shaping Machine
A shaping machine is used to machine surfaces. It can cut curves, angles and many
other shapes.
The major components of a shaper are the ram, which has the tool post with cutting
tool mounted on its face, and a worktable, which holds the part and accomplishes the
feed motion.

38
Shaping Machine (Tool post)
Thetoolposthasbeenturnedatan
anglesothatsideofthematerialcan
bemachined
Thetoolpostisnotangledsothatthe
toolcanbeusedtolevelasurface.
Tool post (clapper box)

39
Shaping Machine (Clapper box)

40
Shaping Machine (Quick Return Mechanism)

41
Shaping Machine (Quick Return Mechanism)

42
Shaping Machine (Quick Return Mechanism)

43
WhatisIndexing?
Indexingistheprocessofevenlydividingthecircumferenceofacircularworkpiece
intoequallyspaceddivisions,suchasincuttinggearteeth,cuttingsplines,millinggroov
esinreamersandtaps,andspacingholesonacircle.
Theindexheadoftheindexingfixtureisusedforthispurpose.
Indexing
<Indexing Head>

44
IndexingHead
Theindexheadoftheindexingfixturecontainsanindexingmechanismwhichisusedto
controltherotationoftheindexheadspindletospaceordivideaworkpieceaccurately.
Asimpleindexingmechanismconsistsofa40-toothwormwheelfastenedtotheindex
headspindle,asingle-cutworm,acrankforturningthewormshaft,andanindexplatea
ndsector.
Sincethereare40teethinthewormwheel,oneturnoftheindexcrankcausestheworm
,andconsequently,theindexheadspindletomake1/40ofaturn;so40turnsofthe
indexcrankrevolvethespindleonefullturn.
Indexing

45
IndexPlateTypes
BrownandSharpetypeconsistsof3platesof6circleseachdrilledasfollows:
PlateI-15,16,17,18,19,20holes
Plate2-21,23,27,29,31,33holes
Plate3-37,39,41,43,47,49holes
Cincinnatitypeconsistsofoneplatedrilledonbothsideswithcirclesdividedasfoll
ow
Firstside-24,25,28,30,34,37,38,39,41,42,43holes
Secondside-46,47,49,51,53,54,57,58,59,62,66holes
Indexing

46
Indexing Methods
SimpleIndexingorPlainIndexing
Theindexplateisfittedonthewormshaftandlockedthroughalockingpin’
Toindextheworkthroughanyrequiredangle,theindexcrankpiniswithdrawnfromtheholeoftheindex
platethantheworkisindexedthroughtherequiredanglebyturningtheindexcrankthroughacalculated
numberofwholerevolutionsandholesononeoftheholecircles,afterwhichtheindexpinisrelocatedint
herequiredhole
Ifthenumberofturnsthatthecrankmustberotatedforeachindexingcanbefoundfromtheformula
N=40/Z
Where
Z-Noofdivisionsorindexingsneededonthework
40–Noofteethonthewormwheelattachedtotheindexingplate,since40turnsoftheindexcran
kwillturnthespindletoonefullturn

47
Supposeitisdesiredtomillagearwitheightequallyspacedteeth.l/8thof40or5turns
(Since40turnsoftheindexcrankwillturnthespindleonefullturn)ofthecrankafter
eachcut,willspacethegearfor8teeth.Ifitisdesiredtospaceequallyfor10teeth,
1/10of40or4turnswouldproducethecorrectspacing.
Thesameprincipleapplieswhetherornotthedivisionsrequireddivideequallyinto40.
Forexample,ifitisdesiredtoindexfor16divisions,16dividedinto40equals
28/16turns.i.eforeachindexingweneedtwocompleterotationsofthecrankplus
8moreholesonthe16holecircleofplate1(PlateI-15,16,17,18,19,20holes)
Indexing Methods

48
Differential Indexing Methods

49
Indexing Methods

50
Indexing Methods

51
Indexing Problems
Refer P.C. Sharma –Vol-II, Page No 157 to 162
Indexing

52
Planner Machine
Planning and shaping are similar operations, which differ in the kinematics of the
process.
Planning is a machining operation in which the primary cutting motion is performed by
the work piece and feed motion is imparted to the cutting tool. In shaping, the primary
motion is performed by the tool, and feed by the work piece

53
Planner Machine

54
Theopen side planer, also known as a single-column planer has a single column
supporting the cross rail on which a tool head is mounted. The configuration of the
open side planer permits very wide work parts to be machined.
A double-column planer has two columns, one on either side of the bed and
worktable. The columns support the cross rail on which one or more tool heads are
mounted. The two columns provide a more rigid structure for the operation but limit
the width of the work that can be handled.
Planner Machine

55
Slotting Machine
Slotting machines can simply be considered as vertical
shaping machine
Vertical shaping machine where the single point tool
reciprocates vertically
Cutting on the downward stroke and upward stroke being
idle
Work table specified for transverse, longitudinal or rotary
movement
Longer stroke length
Wide range of operations for internal surfaces as splines,
keyways and teeth

56
Slotting Machine

57
Slotting Machine

58
Slotting Machine
Vertical slide reciprocated by crank-
connecting rod mechanism
Quick return absent
Intermittent rotation provided by four bar
linkage
The work table rotated by feed rod
connected to worm-worm wheel drive
Working speed(number of strokes per
minute) can be changed by belt pulley
ratio/gear box

59
Work and Tool Holding Devices
Work Holding Devices
Drill Press Vice
Used to hold round, square or odd-shaped rectangular pieces
Clamp vise to table for stability

60
Work and Tool Holding Devices
Work Holding Devices
Angle Vice
Angular adjustment on base to allow operator to drill holes at an angle
without tilting table

61
Work and Tool Holding Devices
Work Holding Devices
V-Blocks
Made of cast iron or hardened steel
Used in pairs to support round work for drilling

62
Work and Tool Holding Devices
Work Holding Devices
Step blocks
Used to provide support for outer end of strap clamps

63
Work and Tool Holding Devices
Work Holding Devices
Angle plate
L-shaped piece of cast iron or hardened steel machined to accurate 90º may
be bolted or clamped to table

64
Work and Tool Holding Devices
Work Holding Devices
Drill Jigs
Used in production for drilling holes in large number of identical parts
Eliminate need for laying out a hole location

65
Work Holding Devices

66
Boring
Inmachining,boringistheprocessofenlargingaholethathasalreadybeen
drilled(orcast)bymeansofasingle-pointcuttingtool(orofaboringhead
containingseveralsuchtools),suchasinboringagunbarreloranengine
cylinder.
Boringisusedtoachievegreateraccuracyofthediameterofahole,andcan
beusedtocutataperedhole.Boringcanbeviewedastheinternal-diameter
counterparttoturning,whichcutsexternaldiameters.

67
Boring Machine
HorizontalBoringMachine
Theworkissupportedonatablewhichisstationaryandtoolrevolvesina
horizontalaxisviaalsopossible.
Workpiecewhichareheavierandasymmetricalcanbeeasilyheldand
machined.

68
Boring Machine
HorizontalBoringMachine
Theboringbarinthissetupmustbeverystifftoavoiddeflectionandvibrationduringcutting.To
achievehighstiffness,boringbarsareoftenmadeofcementedcarbide,whosemodulusofelasticity
approaches620x10
3
MPa
Carbide boring bar

HorizontalBoringMachine
Ahorizontalboringmachinecanperformboring,reaming,turning,threadin
g,facing,milling,groovingandmanyotheroperationswithsuitabletools.
Differenttypesofhorizontalboringmachineshavebeendesignedtosuit
differentpurposes.
69
Boring Machine

70
Boring Machine
HorizontalBoringmachinemechanism
Atabletypemachinehasmovementsmentionedbelow:
Theheadstockandtheendsupportingblockmaybemovedupanddown.
Thespindlemayberotatedwiththedifferentspeeds.
Thespindlemaybemovedinoroutbyhandorpowerforfeeding.
Thesaddleortablemaybemovedbyhandorpower.
Thecolumnsmaybemovedbyhandorpower.

71
Boring Machine
HorizontalBoringmachinemechanism

72
Boring Machine
VerticalBoringmachinemechanism

73
VerticalBoringMachine:
Theworkrotatesonahorizontaltableaboutaverticalaxisand
thetoolisstationaryexceptforfeed.
Machinemaylooklikeaverticallathe.
Largerdiameterandheavyworkpieces,canbesetupmore
quicklythaninlathe.
Multipletoolingmaybeadaptedwithitsturrettypetoolpost,in
creasingtherateofproduction.
Boring Machine

74

75
Boring Machine
VerticalBoringmachinemechanism
Itisusedforlarge,heavyworkpartswithlargediameters;usuallythe
workpartsdiameterisgreaterthanitslength.

76
VerticalBoringOperation
Boring Machine

77
JigBoringMachine
Itusesasinglepointcuttingtoolstomachinesurfacesrapidlyandaccurately.
Cementedcarbideanddiamondtippedtoolsareoperatedataveryhighcuttings
peedtoproduceaccuratelysizedholeswithfinesurface.
Jigboringmachineisaprecisionboringmachine,resemblestoverticalmillingm
achineinconstruction.
AccuratepositioningofholesisachievedbyLeadscrewmethodorMechanical/E
lectricalGaugingmethodorOpticalmeasuringmethod.
Boring Machine

78
JigBoringMachine
Boring Machine

79

80
Itisamachiningprocessforremovalofalayerofmaterialofdesiredwidtha
nddepthusuallyinonestrokebyaslenderrodorbartypecutterhavingas
eriesofcuttingedgeswithgraduallyincreasedprotrusion.
Inshaping,attainingfulldepthrequiresanumberofstrokestoremovethem
aterialinthinlayersstep–by–stepbygraduallyin-feedingthesinglepoint
tool.
Whereas,broachingenablesremovethewholematerialinonestrokeonlyby
thegraduallyrisingteethofthecuttercalledbroach.
Broaching

81
Broaching

82
Broaching
<Finishing hole by broaching>

83
Broaching
<Continuous broaching>

84
Bothpullandpushtypebroachesaremadeintheformofslenderrodsorbarsofvarying
sectionhavingalongitslengthoneormorerowsofcuttingteethwithincreasingheight
(andwidthoccasionally).
Pushtypebroachesaresubjectedtocompressiveloadandhencearemadeshorterinlengthto
avoidbuckling.
Thegeneralconfigurationofpulltypebroaches,whicharewidelyusedforenlargingand
finishingpreformedholes.
Nomenclature of Broach
<Pull type>

85
Nomenclature of Broach

86
Pullendforengagingthebroachinthemachine
Neckofshorterdiameterandlength,wherethebroachisallowedtofail,ifatall,underoverloading
Frontpilotforinitiallocatingthebroachinthehole
Roughingandfinishingteethformetalremoval
Finishingandburnishingteethforfinefinishing
Rearpilotandfollowerrestorretriever
Nomenclature of Broach
<Pull type>

87
Types of Broaching Machine
According to purpose of use
–general purpose
–single purpose
–special purpose
According to nature of work
–internal broaching
–external (surface) broaching
According to configuration
–horizontal
–vertical
According to number of slides or stations
–single station type
–multiple station type
–indexing type
According to tool / work motion
–intermittent (one job at a time) type
–continuous type

88
Major advantages
Very high production rate (much higher than milling, planing, boring et
c.)
High dimensional and form accuracy and surface finish of the product
Roughing and finishing in single stroke of the same cutter
Needs only one motion (cutting), so design, construction, operation an
d control are simpler
Extremely suitable and economic for mass production
Broaching Machine

89
Limitations
Only through holes and surfaces can be machined
Usable only for light cuts, i.e. low chip load and unhardmaterials
Cutting speed cannot be high
Defects or damages in the broach (cutting edges) severely affect product quality
Design, manufacture and restoration of the broaches are difficult and expensive
Separate broach has to be procured and used whenever size, shape and geomet
ry of the job changes
Economic only when the production volume is large.
Broaching Machine

•www.google.co.in
•www.researchgate.net
•www.youtube.com
•https://onlinecourses.nptel.ac.in/
•MikellP. Groover“Fundamentals of Modern Manufacturing Materials, Proc
esses, and Systems”,4
th
Edition,JOHNWILEY & SONS, INC.2010
•E.PaulDeGarmo, Black J.T and Ronald A. Kosher “Materials and Process
es, in Manufacturing”,EightEdition, Prentice –Hall of India, 1997
•James S Campbell “Principles of manufacturing materials and processes”
New Delhi : Tata McGraw-Hill ,1983
•SeropeKalpakjian,Steven R Schmid“Manufacturing Engineering and Tec
hnology” Pearson India, 4th Edition
90
Bibliography

91

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