Stock removal rate and workpiece strength in multi-pass grinding of ceramics

Stock removal rate and workpiece strength are evaluated in terms of machine stiffness and grinding wheel parameters in multi-pass grinding of silicon nitride ceramics. This paper presents theoretical analyses on normal grinding force, actual depth of cut (ADOC) of a grinding wheel, stock removal rate and residual strength of ground workpieces, as well as experimental results to verify the analyses. In the grinding experiments, silicon nitride workpieces are subjected to multi-pass grinding with four diamond wheels of three grit sizes and two bond types, as well as a precision grinder of adjustable stiffness. The electrolytic in-process dressing (ELID) technique is adopted to evaluate how wheel dressing can affect the workpiece strength and stock removal rate in multi-pass grinding. A discussion addresses the issues of strength gain and strength loss for ground workpieces and a recommendation is provided to obtain higher residual strength of ground workpiece.