A SIMPLIFIED APPROACH TO EVALUATING THE THERMAL-BEHAVIOR OF SURFACE ENGINEERED CUTTING TOOLS

It is commonly accepted that both the wear and failure mechanisms whic h develop in cutting tools are predominantly influenced by temperature . In order to predict the wear and failure characteristics of a tool i t is necessary to quantify the temperatures which develop during the c utting operation. In recent years, numerical calculating methods have been widely developed in most areas of engineering and have been used to determine the thermal behaviour of cutting tools. In general, the a pplication of finite element and finite difference techniques has been successful, yet: still relies heavily oil tile accuracy of experiment ally determined boundary conditions. If, however, for a given applicat ion, an approximate solution were all that was required to give an ind ication of the thermal behaviour, then a simplified approach could be applied which would realise savings of rime, money and would broaden t he potential user base. The development of such a technique to determi ne the thermal behaviour of cutting tools is described, with particula r reference to assessing the thermal behaviour of single- and multi-po int cutting tools before and after the application of advanced surface engineered treatments. An extensive programme of empirical and analyt ical work has been undertaken at Sheffield Hallam University to study the performance, life and design characteristics of various standard a nd surface engineered single- and multi-point cutting tools. Data acqu ired from research programmes have been used to predict the temperatur es generated along the tool/chip interface using standard analytical m ethods. A simplified application of finite element techniques has been used to simulate the mode of dissipation of this heat source. The cur rent paper describes the approach with reference lu TiN-coated and sta ndard production indexable inserts (single-point tool) and bandsaw tee th (multi-point cutting tool).