Prediction of critical cutting condition for onset of serrated chip in ductile metallic material using dynamic yield stress

Abstract

Abstract Anticipation of the critical cutting condition for the transition of continuous chip to serrated chip is a fundamental task in machining of ductile metallic material. In this study, the variation of the dynamic yield stress with the increase of cutting speed was utilized as the criterion to predict the critical cutting condition for onset of the serrated chip. In order to accurately and conveniently determine the value of dynamic yielding strength of the workpiece material during the cutting process, an improved Williams’ model in conjunction with a 2D orthogonal slot milling test is proposed. Two typical ductile metals of silicon brass and Ti6Al4V were used as the workpiece material in this framework. Also, the chip morphology obtained in cylindrical turning test was used to validate the predicted results. For the two workpiece materials tested, it is observed that the error between the predicted result and the experimental result is always lower than 12%. The proposed methodology in this work exhibits its superiority in terms of calculation and predicting efficiency, which is still a challenge for traditional analytical method and finite element method.