Page 52 - CITS - Fitter - Trade Theory

FITTER - CITS

Introduction on common defects of grinding wheel

Definition
Grinding wheel is a cutting tool which has many small cutting edges. The abrasive grains in wheel act as grinding
tools, removing material from work piece.

Defects of grinding wheel
Grinding wheels become inefficient due to two main causes known as loading and glazing.
1 Loading
When soft materials such as aluminium, copper, lead etc. are ground, the metal particles get clogged in the pores
of the wheel. This condition is called loading.
2 Glazing
When a surface of the wheel develops a smooth and shining appearance, it is said to be glazed. This indicates
that the wheel is blunt, i.e. the abrasive grains are not sharp.
Effects of loading and glazing
When such grinding wheels are used, there is a tendency to exert extra pressure in order to make the wheels cut
Excessive pressure on the grinding wheel will lead to the fracture of the wheel, excessive heating of the wheel,
weakening of bonding of the wheel and bursting of the wheel.

Safety & precautions While grinding
1 Gloves, safety glasses, hear protection and apron should be worn.
2 Ensure you do not run the grinding wheel above specified RPM
3 Use proper wheel guards on machine before grinding.
4 Remove work piece from grinding wheel before turning machine off.

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CITS : CG & M - Fitter - Lesson 6 CITS : CG & M - Fitter - Lesson 6