超硬刀具高速切削钛合金时的切削力研究

Research on Cutting Force of Superhard Tool in High Speed Cutting of Titanium Alloy

基于锯齿切屑相关理论,以单位切削力、切削力静态分量和动态分量为指标,对PCD/PCBN两种超硬刀具高速切削TC4钛合金的切削力进行对比研究。研究发现:两种超硬刀具高速切削TC4钛合金时,单位切削力大小基本相同,且均随切削速度增大而整体呈略微增加趋势,均随进给量、背吃刀量的增大而减小;单位切削力大小取决于锯齿形切屑基块内材料应变及应变率强化作用和温度弱化作用。两种超硬刀具切削力静态分量大小基本相同,且均随切削速度的增大整体呈略微增大趋势,均随进给量和背吃刀量的增大而增大。两种超硬刀具的切削力动态分量均随切削速度的增大而减小,均随进给量和背吃刀量的增大而增大。PCD刀具的切削力动态分量大于PCBN刀具;切削力动态分量大小与靠近刀尖处发生热塑剪切失稳切削层材料的体积和温度有关。

Based on the theory of sawtooth chips,this paper compares the cutting force of PCD/PCBN superhard tools for high-speed cutting of titanium alloy TC4 with indicators of unit cutting force,static and dynamic components of cutting force.The study found that the unit cutting force of the two superhard tools is basically the same when cutting titanium alloy TC4 at high speed,and both have a slight increase trend as the cutting speed increases,both increase with the increase in the feed rate and the back-feeding amount;The unit cutting force depends on the material strain and strain rate strengthening effect and temperature weakening effect in the sawtooth chip base block.the static components of the cutting force of the two superhard tools are also basically the same,and both show a slight increase trend as the cutting speed increases,both increase with the increase of the feed rate and the back-feeding amount.The dynamic components of the cutting force of two superhard tools decrease with the increase of the cutting speed,and both increase with the increase of the feed rate and the back-feeding amount.The dynamic component of the cutting force of the PCD tool is greater than that of the PCBN tool dynamic component,and it is related to the volume and temperature of the cutting layer material near the cutting edge.