MAINTAINING GRINDING WHEEL

 Maintaining grinding wheels

.differentiate between loading and glazing

. effects of loading and glazing

. differentiate between dressing and turning

Grinding wheels become inefficient due to two main causes known as loading and glazing

Loading

When soft  materials such as aluminum, copper, lead etc. Are ground, the metal particles get clogged in the pores of the wheel. This condition is called loading

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.

When such grinding wheels are used, there is a tendency to exert extra pressure in order to make the wheel 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

Dressing

The purpose of dressing is to restore the correct cutting action of the wheel. Dressing removes the clogs on the surface of the wheel and the blunt grains of the abrasive,, exposing the new sharp abrasive grains of the wheel which can be cut and brought to shape efficiently.

Truing

Truing refers to the shaping of the wheel to make it run concentric with the axis. When a new grinding wheel is mounted, it must be trued before use. The cutting surface of a new wheel may run out slightly due to the clearance between the bore and the machine spindle. Grinding wheels, which are in use, also can run out of true, due to uneven loading while grinding.

Dressing and truing done at the same time.