On-Line Prediction of Impulse Spark and Arc Discharge Removals of Metal Bond in Dry Electrical Discharge Dressing of Diamond Grinding Wheel

The electrical discharge is able to realize efficient dressing for metal-bonded diamond wheel, but the monitoring and prediction of dressing status have been technical bottleneck in industrialization. Hence, the metal bond removal model of impulse spark and arc discharges is proposed to realize on-line monitoring and prediction for micro grain protrusion on diamond grinding wheel surface. The relationship between microremovals of metal bond and impulse spark and arc discharge parameters was investigated for controllable dressing. First, the static and dynamic impulse discharge experiments were carried out to reveal metal bond removal mechanisms of impulse spark and arc discharges; then the relationship between characterized impulse discharge parameters and removal of metal bond was quantitatively analyzed; finally, the dry electro-contact discharge (ECD) dressed coarse diamond wheels were applied to perform smooth surface and mirror grinding of optical glass and mold steels against mechanical dressed wheels. It is found that the critical transition value of arc discharge to spark discharge under static discharge and dynamic discharge conditions were 0.059 and 0.038, respectively. In comparison with mechanical dressing, the dry ECD can obtain higher grain protrusion height to improve ground surface quality, leading to a microscopic smooth surface of BAK3 optical glass and macroscopic mirror-like surface of model steels. It is confirmed that the established relationship model can be effectively used to on-line predict the removal of metal bond with the average prediction error of 10.1% and microscopic grain protrusion by characterized impulse discharge parameters.