The effect of uncut chip thickness on edge chipping and wheel performance in groove grinding of single crystal silicon

摘要

Achieving a long wheel service life and an acceptable level of edge chipping in the groove grinding of single crystal silicon, such as in the die-sawing process, often requires time-consuming trials for proper setting of important process parameters, including wheel selection, feed, speed, and cutting depth. To better understand the effect of various process parameters on edge chipping and wheel performance, this paper proposes a new process variable, the cutting depth ratio (CDR), to characterize the operating conditions of the groove grinding process. Combining the kinematic features of the grinding process and the material fracture criterion, the CDR, defined as the ratio of the maximum uncut chip thickness to the critical depth of cut of silicon, is employed to investigate the effect of uncut chip thickness on groove edge chipping and wheel performance. The magnitude of edge chipping is shown to steadily increase with increasing CDR, indicating increasing brittle behaviour of the material removal process as the uncut chip thickness increases. By using grinding ratio to correlate with wheel performance, it is shown that the grinding ratio first increases with increasing CDR, and reaches a peak value approximately at a CDR value of 1 before falling off at higher uncut chip thickness. The stochastic nature of the chip thickness is used to explain the finding that the best wheel performance occurs around unity CDR.