Modeling of Workpiece Temperature and Thermal Expansion in Dry and MQL Drilling

Abstract

Two modeling methods based on the inverse heat transfer method (IHTM) are presented to predict temperature distribution and thermal distortion in the workpiece during deep-hole drilling. The first method is based on the linear invariant system. This method requires many temperature inputs along the depth but can precisely estimate the time-dependent heat generation and temperature distribution. The second method uses a polynomial function to approximate heat growth. It does not need many inputs but cannot capture abrupt heat changes. These two methods along with experimental validation and discussion on their limitations are introduced. A 3D thermal distortion model is presented to apply the heat generation obtained from IHTM to predict a global part distortion in the workpiece with sequential drilling of multiple deep holes.