Too Sharp for its Own Good – Tool Edge Deformation Mechanisms in the Initial Stages of Metal Cutting

Abstract

Metal cutting simulations have become an important part of cutting tool design and the research in the field in general. One of the most important aspects of modeling is the accuracy of the tool geometry. 3D microscopy is used for measuring the tool edge radius with good accuracy. However, especially with sharp tools, i.e. small tool edge radii, the measurements, no matter how accurate, are not much of a use, since the initial wear, or deformation is so fast in the first 1-30seconds into the cutting, that the tool geometry is significantly different than the one measured from the new tool. The average tool life is often set to 15minutes. Therefore, the cutting simulations that only predict the tool behavior in the first seconds of its lifetime are not very useful in predicting the process variables throughout the tool life. Simulations with creep and elastic-plastic material model however, can predict the initial deformation of the tool. This tool shape can be then used in rigid tool model to predict the process variables in the steady wear region of the tool life. This paper presents simulation model for predicting the initial tool edge deformation for WC-10%Co tool while machining AISI 304 stainless steel. The novelty in this approach is the simultaneous coupled calculation of contact surface temperature and stress and change of the tool shape.