超精密切削切屑形成过程的SPH方法模拟研究

SPH Method Simulation of Chip Formation in Ultra-precision Cutting Prorcesses

采用光滑粒子流体动力学方法对单点金刚石刀具超精密切削AISI-4340钢的切屑形成机理及影响因素进行了数值模拟。数值模拟结果显示:当切削厚度较大(0.9μm和0.6μm)时,超精密切削加工产生切屑的形成机制同普通切削一样属于剪切滑移破坏,切屑呈锯齿状,切削力呈波浪形振荡;当切削厚度较小(0.30μm和0.15μm)时,切屑形成机制由剪切破坏转换为挤压破坏,形成了带状连续切屑,切削力在进入稳定切削阶段后基本保持恒定。

In order to investigate the mechanism of chip formation and the influences of some cutting parameters,a SPH method was used to study the ultra-precision cutting AISI-4340 steel with diamond tool.The simulation results show that the chip formation mechanism in ultra-precision cutting process is the adiabatic shear band formation as the same to general cutting under the condition of the bigger cutting thicknesses（0.9μm and 0.6μm）,the chip morphology is like a saw-tooth,and the cutting force is characterized by oscillatory profiles.With the decreases of the cutting thickness up to 0.30μm and 0.15μm,respectively,the shear localized chip formation mechanism is transformed to the extruded-like chip formation behavior,the chip morphology is like a strap,and cutting force maintains approximately a constant value.