Mec 104

Manufacturing Sciences (Mec-
104)
TERM PAPER
Topic: - Mechanics of Grinding
Submitted By : -
Indranil Bhattacharya
Guided By : - Mr.
Rakesh Kumar
Section :- B5901
Roll No. : -
RB5901A65
Registration No. : -
10907260
Acknowledgment
The completion of any term paper requires coordination, dedication

and a combined effect of various sources. First of I Thank God for making me
capable of completing this term paper. Thereafter I thank Mr. Rakesh Kumar
our MEC 104 lecturer for sparing his valuable precious time in guiding me in
this term paper.
Table of Content
1) Introduction
2) Types of Grinding
 Surface Grinding.
 Cylindrical Grinding
 Centerless Grinding
 Creep-feed Grinding.
3) Grinding Wheels
 Abrasive material
 Grain size
 Bonding Material
 Wheel Grade
 Wheel Structure
4) Mechanics of Grinding
5) Application Guidelines
Introduction
Metal removal process by grinding occurs mainly by chip formation process, similar to that
of machining methods such as turnings or milling, but on a much finer scale. It can produce
very fine finishes and very accurate dimensions; yet in mass production contexts it can also
rough out large volumes of metal quite rapidly. It is usually better suited to the machining of
very hard materials than is "regular" machining (that is, cutting larger chips with cutting tools
such as tool bits or milling cutters), and until recent decades it was the only practical way to
machine such materials as hardened steels. Compared to "regular" machining, it is usually
better suited to taking very shallow cuts, such as reducing a shaft's diameter by half a
thousand of an inch.
In grinding, an abrasive material rubs against the metal part and removes tiny pieces of
material. The abrasive material is typically on the surface of a wheel or belt and abrades
material in a way similar to sanding.
Types of Grinding
Following are the types of grinding:-
1) Surface Grinding.
2) Cylindrical Grinding
3) Centerless Grinding
4) Creep-feed Grinding.
Surface Grinding
Surface grinding is used to produce a smooth finish on flat surfaces. It is a widely used
abrasive machining process in which a grinding wheel cuts chips of metallic or non metallic
substance from a workpiece, making a face of it flat or smooth.
Cylindrical Grinding
Centered grinding involves fixturing the part on a spindle axis as it is ground, as illustrated
below. This configuration can be compared to fixturing a part on a lathe with or without a tail
stock. The abrasive material is on a grinding wheel that rotates in a direction such that rolling
or sliding contact occurs where the wheel and work piece touch.
Centerless Grinding
It is a method of material removal through grinding, similar to centered grinding except for
the absence of the spindle. It has high through-put, i.e. large number of parts can be
manufactured in a short time.
Creep Feed Grinding

Depths of cut 1000 to 10,000 times greater than in conventional surface grinding. Material
removal rate and productivity are increased in creep feed grinding because the wheel is
continuously cutting
Grinding Wheel
Following are parts of Grinding Wheel
1. Abrasive material
2. Grain size
3. Bonding Material
4. Wheel Grade
5. Wheel Structure
Abrasive material
The materials are very hard and wear resistance. An abrasive is a material, often a mineral,
that is used to shape or finish a workpiece through rubbing which leads to part of the
workpiece being worn away. Abrasive materials are made of Aluminium oxide, Silicon
carbide, Cubic boron nitride, Diamond (synthetic).
Grain size
Particle size or grain size refers to the diameter of a grain of granular material, such as
sediment or the lithified particles in clastic rock. Granular material can range from very small
colloidal particles, through clay, silt, sand, and gravel, to boulders.
Bonding Material
It is used to hold the Abrasive material in the wheel.
Wheel Grade
Indicates bond strength in retaining abrasive grits during cutting Depends on amount of
bonding material in wheel structure.
Wheel Structure
It refers to the relative spacing of abrasive grains in wheel. In addition to abrasive grains and
bond material, grinding wheels contain air gaps or pores.
Mechanics of Grinding
Cutting tool is an individual abrasive grain. Differences between the actions of a single grain
from that of a single-point cutting tool are:
1) An individual grain has an irregular geometry
2) The average rake angle of the grains is highly negative
3) Grinding wheel have different radial positions
4) Cutting speeds of grinding wheels are very high.

5) Chip formation by an abrasive grain is shown.
6) Mechanics of grinding and the variables can best be analysed by a surface-grinding

operation.
Dd
7) For external (cylindrical) grinding, l=
1 + ( D Dw )
Dd
8) For internal grinding, l=
1 − ( D Dw )
9) Volume of chip with rectangular cross-sectional area and constant width is
wtl rt 2l
Vol chip = =
2 4
10) Undeformed chip thickness in surface grinding is
4v d
t=
VCr D
Application Guidelines
 To optimize surface finish, select
• Small grit size and dense wheel structure
• Use higher wheel speeds and lower work speeds
• Smaller depths of cut (d) and larger wheel diameters (D) will also help
 To maximize material removal rate, select
• Large grit size
• More open wheel structure
• Vitrified bond
 For steel and most cast irons, use
• Aluminum oxide as the abrasive
 For most nonferrous metals, use
• Silicon carbide as the abrasive
 For hardened tool steels and certain aerospace alloys, use
• Cubic boron nitride as the abrasive
 For hard abrasive materials (e.g., ceramics, cemented carbides, and glass) use
• Diamond as the abrasive

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Manufacturing Sciences (Mec-

The completion of any term paper requires coordination, dedication

Creep Feed Grinding

Following are parts of Grinding Wheel

It is used to hold the Abrasive material in the wheel.

1) An individual grain has an irregular geometry

2) The average rake angle of the grains is highly negative

3) Grinding wheel have different radial positions

4) Cutting speeds of grinding wheels are very high.

6) Mechanics of grinding and the variables can best be analysed by a surface-grinding

9) Volume of chip with rectangular cross-sectional area and constant width is

10) Undeformed chip thickness in surface grinding is

• Use higher wheel speeds and lower work speeds

 To maximize material removal rate, select

• Large grit size

• More open wheel structure

 For steel and most cast irons, use

• Aluminum oxide as the abrasive

 For most nonferrous metals, use

• Silicon carbide as the abrasive

 For hardened tool steels and certain aerospace alloys, use

• Cubic boron nitride as the abrasive

• Diamond as the abrasive

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