A softened affected layer generated in electrolytic grinding at higher electrolytic voltage could not be removed by a spark-out grinding without electrolysis in the previous report. In this report, the electrolysis controlled spark-out grinding is developed in order to remove completely an affected electrolytic ground layer at any electrolytic voltage. Effects of the electrolysis controlled spark-out grinding on finished surface characteristics are experimentally proved by investigating ultra micro hardness on machined surface, surface finish and so on. Main conclusions obtained in this report are as follows: (1) The electrolysis controlled spark-out grinding can prevent the finished surface hardness from decreasing at higher electrolytic voltage in which affected layer is remained after spark-out grinding without electrolysis. (2) A surface finish and an effective spark-out grinding time decrease by the spark-out grinding with an optimum electrolyze-out time. (3) An optimum electrolyze-out time decreases with increasing electrolytic voltage and becomes negative at electrolytic voltage over 7V.
