Electrolytic grinding process for minimizing affected layer (1st report) - Characteristics of affected layer and its reduction process by spark-out grinding without electrolysis

The purpose of this study is to minimize affected layer generated by electrolytic grinding which results in deterioration of gloss or decrease of hardness on machined surface. In this paper, a reduction process of affected electrolytic ground layer by a spark-out grinding process without electrolysis, in which electrolytic effect stops just in the moment of stopping infeed of grinding wheel, is experimentally investigated by analyzing characteristics of electrolytic ground surface with a glossiness meter or an ultra micro hardness tester. Main conclusions obtained in this paper are as follows: (1) The depth of affected layer decreasing hardness is nearly 2.5 times as large as that deteriorating gloss, and both depths of affected layer increase with increasing electrolytic voltage. (2) In the case of higher electrolytic voltage, the stock removal in spark-out grinding process without electrolysis is less than the depth of affected layer decreasing hardness generated in steady electrolytic grinding process. So after finish of spark-out grinding, an affected layer decreasing hardness is remained on finished surface on which glossiness is recovered up to that of mechanical ground surface.