刀具前角对单晶硅超精密加工表面质量的影响

Effect of tool rake angle on surface quality of single-crystal silicon during ultra-precision machining

为了解决单晶硅加工表面质量各向异性的问题,应用分子动力学方法研究刀具前角对单晶硅加工表面质量的影响。建立4种调整前角的切削模型,分析单晶硅相变、应力、切削力和摩擦系数。切削单晶硅(111)[-211]晶向的结果表明,负前角并不是越大越好。刀具前角调整到-20°时,产生的具有5、6配位数的硅原子数最少,亚表面损伤程度最低,此时的静压峰值也是最小的。通过调整切削前角,刀具产生最适静应力,从而控制高压相变的发生,实现对加工表面各向异性的消减。

In order to solve the problem of surface quality anisotropy of processed single-crystal silicon,molecular dynamics method was applied to study the effect of the rake angle of the tool on the surface quality of single-crystal silicon. Four cutting models for adjusting the rake angle were established to analyze the phase transformation,stress,cutting force and friction coefficient of single crystal silicon.The result of cutting the crystal orientation of single-crystal silicon(111)[-211]showed that the biggest negative angle was not always greatest. When the tool rake angle was adjusted to-20°,the number of silicon atoms with5 and6 coordination numbers was the smallest,and the subsurface damage is the lowest,the hydrostatic pressure peak is also the smallest at the same time. By adjusting the rake angle,the tool generated the optimal static stress,so as to control the occurrence of high-pressure phrase transition and realize the reduction of the anisotropy of the machined surface quality.