滚珠丝杠硬旋铣加工未变形切屑建模及切削力研究

Research on Modeling of Undeformed Chips and Cutting Force in Hard Whirling of Ball Screw

滚珠丝杠硬旋铣加工过程中切削力具有复杂时变特性,目前尚未获得切削力的精确模型,给硬旋铣工艺参数优化及刀具结构精准设计带来了困难。基于旋风铣加工的运动规律,利用数字化建模方法,建立了未变形切屑的精确三维模型。通过切片处理获取未变形切屑各瞬时截面,研究了未变形切屑瞬时厚度、未变形切屑横截面积及刀-屑接触长度的变化规律。选取8个未变形切屑截面建立数值仿真模型,利用Advantedge软件分析得到对应的切削力,并拟合出硬旋铣加工单刃全周期的切削力的时变曲线。最后通过硬旋铣加工试验,验证数值仿真。研究表明,硬旋铣加工过程中,切削力曲线呈先增大后减小,在刀-屑接触长度最长时切削力数值达到最大。

The cutting force has complex time-varying characteristics during the hard whirling of ball screw,so the precise model of the cutting force has not been obtained,which brings difficulties to the optimization of the technological parameters of hard whirling and the precise design of the tool structure.In this paper,based on the motion law of hard whirling,an accurate 3D model of undeformed chip is established by using digital modeling method.The instantaneous sections of the undeformed chips were obtained by slicing,and the variation rules of the instantaneous thickness of the undeformed chips,the cross-sectional area of the undeformed chips and the length of the cutter-chip contact were studied.Eight undeformed chip sections were selected to establish the numerical simulation model,and the corresponding cutting force was obtained by using Advantedge software analysis,and the time-varying curve of the cutting force for single-edge full cycle machining by hard whirling was fitted.Finally,the numerical simulation is verified by the hard whirling experiment.The research shows that in the process of hard whirling,the cutting force curve increases first and then decreases,and the cutting force value reaches the maximum when the cutter-chip contact length is the longest.