V形微結構刀具之可行性探討

Abstract

本研究與直條形微結構車刀比較，探討v形微結構車刀用於切削性改善的可行性。將v形微結構應用在車刀上的概念來自液動潤滑，目的是增加切削時的潤滑性。v形微結構的設計首先由潤滑理論出發，再透過滑動平板實驗找出適合的溝槽角度，接著會進行切削實驗評估v形微結構車刀對於切削性改善的可行性。實驗結果顯示在切削長度達300公尺後摩擦力與摩擦係數比起傳統刀具下降11 %與7 %，與直條溝槽車刀相比下降4 %與3 %，刀面最大積屑高度減少26 %，副切削刃的犬牙磨耗長度下降20 %，表面粗糙度Ra值低於直條溝槽，最後由切屑形貌判斷v形微結構車刀之摩擦力與切削溫度低於直條微結構車刀，使得切屑外觀較捲、顏色較亮。因此v 形微結構車刀具有改善切削性的可行性。將來若能再改善其他因素，例如對溝槽尺寸進行最佳化設計，以及選用高黏度切削液，則v 形微結構車刀對切削性的改善會更加顯著。

This thesis illustrated the feasibility of machinability improved by a tool with v shape micro textures in comparing with a tool with stripe textures. The concept of adopting the v shape textures on cutting tool came from hydrodynamic lubrication. The purpose is to increase lubricity in cutting. The design of v shape textures started from lubrication theory, then a sliding plates test was conducted to determine the appropriate groove angle, and the cutting experiment was conducted later to evaluate the machinability improved by the tool with v shape textures. The results showed that after cutting for 300 m the friction force and coefficient of friction is 11 % and 7 % less than conventional tool, and 4 % and 3 % less than those of a tool with stripe textures. The maximum height of chip adhesion reduced 26 %.The length of notch wear on secondary flank reduced 20 %. The surface roughness (Ra) is lower than a tool with stripe textures. Finally the chip appearance produced by a tool with v shape textures is bright and curly, which showed the friction force and the cutting temperature were lower than that of a tool with stripe textures. Consequently, the machinability improved by a tool with v shape micro textures is better than that of conventional cutting tools. If more improvements were adopted in future research, such as the optimum design of groove dimensions and high viscosity lubricant, the machinability will be further improved.