Grinding wheel

Grinding

1. G.M.C PolyteChniC,
Shahada
1
PSGVP Mandal’s

2. Grinding Wheel.
Presentation by :-
Nathani Sumeet Samad.
Nerkar Ganesh Chunilal.
Girase Devang Dipak.
Under the Guidance of:
Prof. S.S.Patil
(HOD Mech Dept.)

3. Grinding :-
A Grinding wheel is a multi-tooth cutter made up
of hard particles known as Abrasive which have
been crushed to leave sharp edges for machining.
The wheel may consist of one piece or segments
of abrasive blocks built up into a solid wheel.
Every grinding wheel has two constituents:-
a) Bond that holds the abrasives grains.
b) Abrasives used for cutting.
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4. Grinding wheels:
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5. Basic functions of grinding wheel:-
Removal of stock.
Generation of cylindrical, flat and curved
surfaces.
Production of highly finished surface.
Cutting off operations.
Production of sharp edges and points.
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6. Abrasives:-
An abrasive is an hard and tough substance. It
has many sharp edges. An abrasive cuts or
wears away materials that are softer than
itself.
An abrasive is a substance that is used for
grinding and polishing operations. It is used for
cutting materials.
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7. Examples of Abrasives:-
Sand stone.
Emery / Corundum.
Diamond.
Garnet.
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Types Abrasives Structure

8. Construction of grinding wheel:-
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9. Shapes of Grinding wheel:-
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10. Specifications of Grinding wheel
(Designation) :-
Eg :- 51 A 36 L 5 V 40
51 – Manufacturers symbol (optional)
A – Abrasive (Aluminium oxide)
36 – Grain size (Medium)
L – Grade (Medium)
5 – Structure (Dense)
V – Bond (Vitrified)
40 – Manufacturer symbol (optional)
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11. Dressing of Grinding wheel :-
Dressing is the operation of removal of the dull
and worn-out grains, metal particles from the
cutting surface of a grinding wheel, to restore
its cutting ability for grinding.
The frequency of dressing will depend upon the
type of wheel, application, material to be
grounded, etc.
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12. Dressing Tools:-
Diamond tool.
Wheel dresser: a)
Star dresser. b)
Locked dresser. c)
Corrugated-disc type dresser. d)
Cylinder dresser.
Disc dresser.
Abrasive sticks.
Abrasive wheel dresser.
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13. Truing of Grinding wheel:-
Truing is the process of removal of abrasive
materials from the cutting face of the wheel
and the sides of the wheel so that the wheel
runs true with respect to the axis of rotation.
Truing is carried out with a diamond which has a
shearing action on the abrasive grains and the
bond and so removes irregular group of grains.
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14. Truing & Dressing of Grinding
wheel:-
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Fig : 1 Shows wheel
surface after
Truing.
Fig : 2 Shows wheel
surface after
Dressing.

15. Selection criteria for Grinding wheel:-
Constant factors:
a) Material to be grounded.
b) Amt. of stock removal & finish
required. c) Area of contact.
d) Type of
grinding machine.
Variable factors:
a) Wheel speed.
b) Work speed.
c) Machine
operation.
d) Personal factor.
Other factors:
a) Severity of grinding
operation. b) Type of
bond to be used.
c) Grain size, grade, structure.
d) Wet / Dry grinding.
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16. Balancing of Grinding wheel:-
When a new grinding wheel is used, it should be
first checked for proper balance. Most
manufacturers balance their wheels before
selling them.
A wheel is said to be unbalanced when some
portion of it is heavier, whereas the other is
lighter. An unbalanced wheel will greatly affect
the surface finish and accuracy of the work.
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17. Effect of unbalanced wheel:-
At high rotational speeds, slight unbalance will
produce vibrations and will cause waviness in
the work surface.
Unbalance may cause the wheel to break, with
chances of damage to the machine and serious
injury to the operator.
Excessive vibration will damage the spindle
bearings.
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18. Methods of balancing Grinding
wheel:-
Static balancing :-
In this method wheel is removed from machine
for balancing.
Dynamic balancing :-
In this method wheel is not removed from the
machine for balancing. Balancing is done on the
machine itself.
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19. Safety precautions:-
Use of the right wheel.
Test the wheel before use.
Use mounting blotters.
Enough tightening of flange bolts.
Do not exceed maximum speed.
Use safety glasses.
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20. Types Grinding machines:-
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Stationary Grinder Portable Grinder