Internal grinders are used to finish tapered (or) straight formed holes to the correct size, shape and finish.
⦁ The depth of cut depends upon the diameter of the hole
⦁ In the roughing process may vary from 0.02 to 0.05 mm
⦁ For finishing operations vary from 0.002 to 0.01 mm
Mostly internal grinders are horizontal and also few vertical ones in use.
The internal grinders are three types they are.
- Chucking grinders
- Planetary grinders
- Centreless grinders
In The chucking grinder’s process the work piece is chucked and rotated about its own axis to bring all parts of the bore and other curved surface to be ground in contact with the grinding wheel. The chucking types of grinders are classified into two types
⦁ Plain internal grinders
⦁ Universal grinders
Generally there are three types works are performed by the Chucking grinders are.
⦁ In the first process the wheel is rotated but has no longitudinal movement while the work is slowly rotated and traversed back and forth.
⦁ In the second process the wheel is rotated and at the same time reciprocated back and forth through the length of the hole. The work is slowly rotated but has no lateral and cross movement.
⦁ In the third process known as the internal and face grinders. This grinder has two wheels side by side mounted on a horizontal overhead bar.
In a planetary grinding method the work piece is mounted on the reciprocating table and is not revolved. The planetary grinding is limited to large.
The grinding wheel is providing rotary and planetary motions to grind cylindrical holes.
In the centreless grinding process, the work is supported by three rolls they are.
⦁ Regulating roll
⦁ Supporting roll
⦁ Pressure roll
The pressure roll is to hold the work firmly against the support and regulating rolls.