研究了磷酸二氢钾(KDP)晶体飞切加工过程中温度场的分布, 探索了切削温度对KDP晶体切削过程的影响。首先, 采用热力耦合有限元分析对KDP晶体切削过程进行了仿真, 获得了不同切削深度下材料内部温度场的分布。分别使用飞切机床和纳米压痕仪在不同速度下切削KDP晶体, 发现不同切削速度下形成的切屑的微观形貌存在显著差异, 分析指出这可能是由于在不同切削速度下切削区域温度差异导致的。最后, 对低速加工过程中获得的切屑进行加热试验, 并观测了不同温升条件下切屑微观形貌的变化。飞切加工仿真实验显示: 当切深为200 nm时, 切削区域的温度达到110 ℃; 而实际实验结果表明: 当温度超过100 ℃时, 切屑的微观形貌会发生明显变化。综合仿真及实验结果可知: 在KDP晶体飞切加工过程中切削区域的温度将超过100 ℃, 因此在对KDP晶体切削机理进行研究时, 必须考虑温度对材料力学性能及其去除过程的影响。

This paper researches the thermal field distribution of a Potassium Dihydrogen Phosphate (KDP) crystal in fly-cutting process, and explores the influence of cutting temperature on the fly-cutting process of KDP crystal. Firstly, the thermal-mechanical coupled Finite Element Method(FEM) was conducted to simulate the fly-cutting process of KDP crystal and to obtain the temperature fields under different cutting depths. Then, a fly-cutting machine and a nanoindentation instrument were used to cut the KDP crystal at different speeds. It was found that the microscopic morphologies of the chip formed under different cutting speeds are greatly different, and this may result from the different temperature rises at different cutting speeds. Finally, the chip formed under lower cutting speed was heated at different temperatures and the morphology of the heated chip was observed. The simulation results demonstrate that the temperature in the cutting zone rises to as much as 110 ℃ when the cutting depth increases to 200 nm. Moreover, the experiment results indicate that the chip morphology will change at 100 ℃. It concludes by simulation and experiments that the maximum temperature exceeds 100 ℃ in fly-cutting of KDP crystal. So, it suggests that the effect of cutting temperature on the mechanical property and removal process in fly-cutting of KDP crystal should be considered.