ETRANSIENT, THREE-DIMENSIONAL HEAT TRANSFER MODEL FOR THE LASER ASSISTED MACHINING OF SILICON NITRIDE: II.ASSESSMENT OF PARAMETRIC EFFECTS

摘要

In a companion paper (J.C.Rozzi,F.E.Pfeferkorn,F.P.Incropera,Y.C.Shin,Transient,three-dimen sional heat transfer model for the laser assisted machining of silicon nitride:I. Comparison of predictions with measured surface temperature histories, International Journal of Heat and Mass Transfer 43 (2000) 1409-1424),experimental validation was provided for a transient, three-dimensional heat transfer model of the LAM of a silicon nitride workpiece. In this paper, the model is used to elucidate the influence of operating parameters on thermal conditions within the workpiece. Calculations reveal that thermal energy generation in the primary shear zone has a significant influence on the workpiece temperature distribution, while the effects of heat transfer at the tool flank interface may be neglected. Although temperatures at the material removal plane were only moderately influenced by an increase in the workpiece rotational speed, a reduction in total laser energy deposition due to increase laser/tool translational velocity or decreased laser power may preclude the attainment of a minimum material removal temperature corresponding to the softening temperature range of he YSiAlON gassy phase.