How to choose proper grit for cbn grinding wheels?
It is clear from the fact that grit particle size is the restricting factor for infeed rate in reciprocating grinding and for crossfeed in creep feed grinding. In practice infeed rates with fine-grit wheels; Use Coarse-Grit Wheels for rough grinding.
Excessive infeed rates cause accelerated bond wear, rapidly incrasing grit projection. The results in weakening of bond retention forces causing retention forces causing grit to fail out of bond, resulting in poor wheel life.
Other things being eaual the coarser wheel will generally have longer life-without additional costs, since the grit size has on effect on the price of a wheel. General seletion principle: Not as fine as possible but as coarse as permissible.