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.

预期从连续切屑过渡到锯齿状切屑的临界切削条件是加工延性金属材料的一项基本任务。在这项研究中，动态屈服应力随切削速度的增加而变化，被用作预测锯齿切屑开始的临界切削条件的标准。为了准确方便地确定切削过程中工件材料的动态屈服强度值，提出了一种改进的威廉姆斯模型并结合二维正交槽铣试验。在此框架中，使用了两种典型的韧性金属硅黄铜和Ti6Al4V作为工件材料。此外，在圆柱车削试验中获得的切屑形态用于验证预测结果。对于测试的两种工件材料，可以观察到，预测结果与实验结果之间的误差始终低于12％。这项工作中提出的方法论在计算和预测效率方面显示出其优越性，这仍然是传统分析方法和有限元方法所面临的挑战。