Thermal modeling of the metal cutting process - Part II: temperature rise distribution due to frictional heat source at the tool-chip interface

Heat partition and the temperature rise distribution in the moving chip as well as in the stationary tool due to frictional heat source at the chip-tool interface alone in metal cutting were determined analytically using functional analysis. An analytical model was developed that incorporates two modifications to the classical solutions of Jaeger's moving band (for the chip) and stationary rectangular (for the tool) heat sources for application to metal cutting. It takes into account appropriate boundaries (besides the tool-chip contact interface) and considers non-uniform distribution of the heat partition fraction along the tool-chip interface for the purpose of matching the temperature distribution both on the chip side and the tool side. Using the functional analysis approach, originally proposed by Chao and Trigger (Transactions of ASME, 1951; 73:57-68), a pair of functional expressions for the non-uniform heat partition fraction along the tool-chip interface - one for the moving band heat source (for the chip side) and the other for the stationary rectangular heat source (for the tool side) were developed. Using this analysis, the temperature rise distribution in the chip and the tool were determined for two cases of machining, namely, conventional machining of steel with a carbide tool at high Peclet number (N-Pe approximate to 5-20) and ultraprecision machining of aluminum with a single-crystal diamond tool at low Peclet number (N-Pe-0.5). The calculated temperature rise distribution curves on the two sides of the tool-chip interface are found to be well matched for both cases. The analytical method developed was found to be much faster, easier to use, and more accurate than various numerical methods used earlier. Further, the model provides a better physical appreciation of the thermal aspects of the metal cutting process. (C) 2000 Elsevier Science Ltd. All rights reserved.