THERMAL ASPECTS OF MACHINING - A BEM APPROACH

Elevated temperatures generated in machining operations significantly influence the chip formation mechanics, the process efficiency and the surface quality of the machined part. A BEM approach is used here to analyse the thermal aspects of machining processes. Particular attenti on is given to modeling of the tool-chip, chip-workpiece, and tool-wor kpiece interfaces. An exact expression for matching the boundary condi tions across these interfaces is developed to avoid any iterations. A direct differentiation approach (DDA) is used to determine the sensiti vities of temperature and flux distributions with respect to various d esign parameters. The numerical results obtained by the BEM are first verified against existing analytical and FEM results. The temperature and flux fields for various machining conditions, along with their sen sitivities, are presented next. The situations of progressive flank an d crater wear of the tool with continued machining are also considered , and their effects on thermal fields are investigated. The BEM is fou nd to be very robust and efficient for this class of steady-state cond uction-convection problems. The application of DDA with BEM allows eff icient determination of design sensitivities and avoids strongly singu lar kernels. This approach also provides a new avenue toward efficient optimization of the thermal aspects of machining processes.