In situ imaging based thermo-mechanical analysis of built-up edge in cutting process

Abstract

The built-up edge (BUE) usually occurs near the cutting edge with a negative rake angle at a low cutting speed. It serves as the cutting edge and imposes a great influence on the cutting process. However, the studies of BUE remain a challenge due to the difficulties in the BUE quantification, i.e., the experimental kinematics analysis as well as the numerical simulation of its thermo-mechanical characteristics. In this study, we propose an in situ imaging based thermo-mechanical analysis of the influences of BUE on the metal cutting process. The morphologies of the BUE and chip are identified through high-speed filming. With the captured images, the digital imaging correlation technique is implemented to derive the kinematic field during the cutting process. An incremental cutting process with a small cutting length is numerically simulated with the identified BUE and chip morphologies as inputs, in which the predicted cutting forces are validated successfully against the experimental measurements. With the experimental determination of the BUE and kinematic field, the formation of the BUE and its influences on the cutting process can be analyzed. It is experimentally observed that a cutting speed of 120 m/min leads to a minimum influence on the cutting process, for instance, smallest BUE with least occurrence rate as well as the least changes to the uncut chip thickness. In addition, the cutting temperature and stress fields in deformation zones exhibit remarkable BUE sharpening effects for different cutting speeds.