A new mechanistic friction model for the oblique cutting with tool wear effect

•Friction in oblique machining process is modeled and investigated.•The equivalent rake face and rake angle concept is presented.•Tool wear was measured and visualized.•Tool wear distinctly changes friction.•Friction coefficient for oblique and orthogonal cutting is compared.

This paper presents a new model of friction under three-dimensional process arrangement in which the simple Merchant's model is extended by the influence of the inclination angle and relevant variations of the rake angle caused by tool wear. In the first step, friction and normal forces were computed from the three components of the resultant cutting force. In the second step, the values of the rake angle recorded on the worn part of the tool were implemented into this model. As a result, the obtained values of the friction coefficient differ distinctly from those computed for classical orthogonal cutting. The new friction model was tested for the machining of spheroidal cast iron using CBN tools, although its universal character.