Determination of the Chip–Tool Contact Length in Orthogonal Cutting

This work presents an experimental–numerical approach aimed at determining the chip–tool contact length during orthogonal cutting of annealed AISI 4340 steel (223 HV) with TiN-coated tungsten carbide inserts. Initially, pin-on-disc tests were performed, followed by orthogonal cutting tests. The components of the cutting force were used to calculate the coefficient of friction in orthogonal cutting, and its value was compared with those obtained under sliding. Moreover, the cutting force components obtained experimentally were used to assess the reliability of the finite element model and estimate the temperature in the cutting zone. The contact length between chip and rake face was calculated based on the experimental feed force and shear strength of the work material and was compared with the results provided by an analytical model. The experimental–numerical approach can be considered more accurate due to the fact that it considers the effect of the tool–chip interface temperature on the shear strength of the work material. However, the analytical model is quite straightforward, since it only requires the values of chip thickness and undeformed chip thickness to estimate the tool–chip contact length.