Grinding process for the finest surface finish with super-soft grade resinoid bond wheel

The polyvinyl alcohol (PVA) bond wheel is a typical elastic wheel using in precision finishing of a cylinder, a roll, a magnetic head and so on, but it can't allow using grinding fluid because of its too poor water resistance. So the super-soft grade resinoid wheel, of which the bonding material is prepared by the interaction of PVA and thermosetting plastics, is developed. The surface roughness decreases down to the minimum just after the start of plunge grinding. In this paper, the grinding method with the resinoid bond wheel is proposed to achieve the finest surface finish of workpiece, based on such minimizing phenomenon of surface roughness. Main conclusions obtained in this paper are as follows: (1) The finest surface finish can be obtained by spark-out grinding operation just at the right moment when the surface roughness of workpiece decreases down to the minimum. (2) The surface finish by this grinding operation decreases with decreasing the initial surface roughness, but the shrinkage in surface roughness during the spark-out grinding process increases with increasing initial surface roughness. (3) The repetition of this grinding operation without dressing makes the surface finish smaller than that by a general grinding operation with larger depth of cut before spark-out grinding.