Dry Generating Gear Grinding: Hierarchical Two-Step Finite Element Model for Process Optimization

Abstract

Recent developments in the automotive industry have led to more stringent requirements for transmission gear quality. This aspect, combined with a massive increase in the number of gears produced per year, has seen generating grinding become the finishing method of choice for mass production of gears. Due to the intrinsic nature of grinding, this process remains the only manufacturing phase that still requires the widespread use of lubricant. With the aim of improving the environmental sustainability of this process chain, recent attempts at performing dry grinding without lubricant have highlighted the critical aspect of thermal damage produced under these conditions. In the present work, a two-step finite element modeling approach is presented for predicting thermal damage during dry generating gear grinding. Grinding forces and thermal energy generated by the interaction of a single grain with the workpiece are first calculated based on real grain geometry acquired via computed tomography. Results of this single-grain model are then applied at a gear tooth level together with process kinematics to determine the temperature distribution during dry generating grinding. Single-grain and generating grinding tests are performed to verify the predicted onset of thermal damage and the ability to optimize process parameters using the proposed hierarchical modeling approach.