In-process evaluation of grit protrusion feature for fine diamond grinding wheel by means of electro-contact discharge dressing

This paper introduces a new in-process evaluation method for grit protrusion feature on wheel surface by monitoring discharge current trace during electro-contact discharge (ECD) dressing of metal-bonded fine diamond grinding wheel. First an impulse discharge machining experiment was carried out to investigate the correlation between metal bond removal and discharge parameters, namely discharge current Ie and discharge pulse duration τe. Then ECD dressing experiment for #600 diamond grinding wheel was conduced to analyses the quantitative effect of the discharge parameters (Ie and τe), derived from discharge current trace between wheel and dresser (electrode), on grit protrusion feature of wheel surface. The result shows that the grit protrusion feature is sensitive to the discharge parameters (Ie and τe) with reference to mean diamond grit size dgm. Further, the discharge parameters (Ie and τe) in ECD dressing should conform to the discharge variables’ requirement of 5.41×Ie0.77×τe0.19<(dgm)/(2), by which the grit protrusion feature may be evaluated and the dressing process variables may be determined. Finally, the in-process evaluation method was successfully applied to ECD dressing of #1500 diamond grinding wheel for valid grinding of hard-brittle materials.