放电热与交变切削力耦合的金刚石磨粒修整研究  

Diamond Grain Truncating Technology Coupled with Discharge Thermal and Alternating Cutting Force

作　　者：黄家骏 何铨鹏 谢晋[1] 杨浩[1] HUANG Jiajun;HE Quanpeng;XIE Jin;YANG Hao(School of Mechanical&Automotive Engineering,South China University of Technology,Guangzhou 510640)

机构地区：[1]华南理工大学机械与汽车工程学院,广州510640

出　　处：《机械工程学报》2022年第15期144-151,共8页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51975219);广东省自然科学基金(2020A1515010807);广东省科技计划(2020A0505100003);中央高校基本科研业务费专项资金资助项目。

摘　　要：超硬金刚石是加工硬质零部件的工具材料,但精密加工需控制其切削刃形貌。基于金刚石热化学石墨化去除机理,提出放电热与交变切削力耦合的金刚石磨粒修整修平方法,旨在磨削中确保离散分布的磨粒切削刃一致性。在修整中将砂轮与电极间的放电热传递至磨粒切削界面后与摩擦热融合,且利用交变切削力增强其表面热化学石墨化去除。进而,探究石墨化温度和切削刃温升率探究热力间的作用机制,分析交变切削力对磨粒修平面积、修整效率和磨削质量的影响等。结果表明,铁原子相对铜原子更容易扩散到金刚石原子结构中,将石墨化温度从850℃下降到750℃。在铁原子催化下,交变力与放电热耦合可增加切削刃温升率,提高金刚石修整效率约20倍,使磨粒修平面积增大约3倍。最后,采用#46粗金刚石砂轮对硬质模具钢进行干磨削,可减少应力集中和避免热损伤,Ra达到290 nm,实现环保、高效的精密加工。Superhard diamond is a tool material for machining hard parts,but precision machining needs to control its cutting edge morphology.Based on the diamond removal mechanism by thermochemical graphitization,a diamond grain truncating technology coupling discharge thermal and alternating cutting force is proposed to ensure the consistency of discrete grain cutting edges in a grinding.In the truncating,the discharge thermal between the grinding wheel and electrode is transmitted to the grain cutting interface through the chip,and then fused with the friction thermal.The alternating cutting force is used to enhance the thermochemical graphitization removal on the cutting interface.Furthermore,the thermomechanical couple mechanism is explored for the graphitization temperature and temperature rate of cutting edge.The effect of alternating cutting force on grain truncation area,truncating efficiency and grinding quality is analyzed.It is showed that iron atom is easier to diffuse with diamond atoms than copper atoms,the graphitization temperature of diamond can be reduced from 850℃by copper atom to 750℃by iron atom.Under the catalysis of iron atom,the coupling of alternating force and discharge thermal can improve the temperature rate of cutting edge,increase the diamond truncating efficiency by ca.20 times and the grain truncation area by ca.3 times.Finally,dry grinding of hard die steel with#46 rough diamond grains truncated can reduce stress concentration and avoid thermal damage.The roughness can be reduced to 290 nm,so as to realize environmental protection and efficient precision machining.

关 键 词：金刚石磨粒 热化学去除 放电加工 精密磨削 

分 类 号：TG580[金属学及工艺—金属切削加工及机床] TG661