Transient, three-dimensional heat transfer model for the laser assisted machining of silicon nitride: II. Assessment of parametric effects

Citation
Jc. Rozzi et al., Transient, three-dimensional heat transfer model for the laser assisted machining of silicon nitride: II. Assessment of parametric effects, INT J HEAT, 43(8), 2000, pp. 1425-1437
Citations number
13
Categorie Soggetti
Mechanical Engineering
Journal title
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
ISSN journal
00179310 → ACNP
Volume
43
Issue
8
Year of publication
2000
Pages
1425 - 1437
Database
ISI
SICI code
0017-9310(200004)43:8<1425:TTHTMF>2.0.ZU;2-F
Abstract
In a companion paper (J.C. Rozzi, F.E. Pfefferkorn, F.P. Incropera, Y.C. Sh in, Transient, three-dimensional heat transfer model for the laser assisted machining of silicon nitride: I. Comparison of predictions with measured s urface temperature histories, International Journal of Heat and Mass Transf er 43 (2000) 1409-1424), experimental validation was provided for a transie nt, three-dimensional heat transfer model of the LAM of a silicon nitride w orkpiece. In this paper, the model is used to elucidate the influence of op erating parameters on thermal conditions within the workpiece. Calculations reveal that thermal energy generation in the primary shear zone has a sign ificant influence on the workpiece temperature distribution, while the effe cts 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 las er energy deposition due to increased laser/tool translational velocity or decreased laser power may preclude the attainment of a minimum material rem oval temperature corresponding to the softening temperature range of the YS iAlON glassy phase. Due to the comparatively small influence on radial temp erature gradients within the material removal plane, the minimum material r emoval temperature decreased only slightly with increasing depth of cut. Ho wever, the amount of laser energy deposition on the unmachined workpiece in creased significantly with increasing laser-tool lead distance, yielding an attendant increase in the material removal temperature. For a fixed laser- tool lead, energy deposition at the unmachined workpiece surface increased with decreasing laser beam diameter and increasing power. (C) 2000 Elsevier Science Ltd. All rights reserved.