Continuous generating grinding — Material engagement in gear tooth root machining

•The material engagement during gear tooth root machining is presented.•The normal feed rate vfn correlates to the tool wear and the gear subsurface load.•A method for calculation of the maximal normal feed rate vfn.max is proposed.

The load carrying capacity of the tooth root mainly depends on its fillet geometry and subsurface integrity, which are affected by the hard finish processes. This paper analyzes the contact conditions in continuous generating grinding and aims to fill the knowledge gap concerning the elementary effects during penetration of tool tip and gear tooth root fillet. In order to obtain fundamental understanding of this process, the three-dimensional removal simulation software CutS® was used. The gained results show that the simulated data correlate to experimental results concerning tool wear and thermal load on gear subsurface. Thereby, the reasonable use of vitrified bond corundum-tools is severely restricted by grinding burn and macro-geometrical wear, which can be described by the tool surface normal feed rate vfn.max. An analytical approach to the calculation of vfn.max is presented, which can be applied on a practical scale.