Compound machining of silicon carbide ceramics by high speed end electrical discharge milling and mechanical grinding  

作　　者：JI RenJie LIU YongHong ZHANG YanZhen WANG Fei CAI BaoPing LI Hang 

机构地区：[1]College of Electromechanical Engineering,China University of Petroleum,Dongying 257061,China

出　　处：《Chinese Science Bulletin》2012年第4期421-434,共14页

基　　金：supported by the National Natural Science Foundation of China(50675225);the Scientific Research Personnel Service Project from the Ministry of Science and Technology of China(2009GJC60047);the Independent Innovation Research Project from China University of Petroleum(11CX04031A)

摘　　要：A compound process that integrates end electrical discharge (ED) milling and mechanical grinding to machine silicon carbide (SiC) ceramics is developed in this paper. The process employs a turntable with several uniformly-distributed cylindrical copper electrodes and abrasive sticks as the tool, and uses a water-based emulsion as the machining fluid. End electrical discharge milling and mechanical grinding happen alternately and are mutually beneficial, so the process is able to effectively machine a large surface area on SiC ceramic with a good surface quality. The machining principle and characteristics of the technique are introduced. The effects of polarity, pulse duration, pulse interval, open-circuit voltage, discharge current, diamond grit size, emulsion concentration, emulsion flux, milling depth and tool stick number on performance parameters such as the material removal rate, tool wear ratio, and surface roughness have been investigated. In addition, the microstructure of the machined surface under different machining conditions is examined with a scanning electron microscope and an energy dispersive spectrometer. The SiC ceramic was mainly removed by end ED milling during the initial rough machining mode, whereas it is mainly removed by mechanical grinding during the later finer machining mode; moreover, the tool material can transfer to the workpiece surface during the compound process.A compound process that integrates end electrical discharge （ED） milling and mechanical grinding to machine silicon carbide （SIC） ceramics is developed in this paper. The process employs a turntable with several uniformly-distributed cylindrical copper electrodes and abrasive sticks as the tool, and uses a water-based emulsion as the machining fluid. End electrical discharge milling and mechanical grinding happen alternately and are mutually beneficial, so the process is able to effectively machine a large surface area on SiC ceramic with a good surface quality. The machining principle and characteristics of the technique are introduced. The effects of polarity, pulse duration, pulse interval, open-circuit voltage, discharge current, diamond grit size, emulsion concen- tration, emulsion flux, milling depth and tool stick number wear ratio, and surface roughness have been investigated. In on performance parameters such as the material removal rate, tool addition, the microstructure of the machined surface under different machining conditions is examined with a scanning electron microscope and an energy dispersive spectrometer. The SiC ceramic was mainly removed by end ED milling during the initial rough machining mode, whereas it is mainly removed by mechanical grinding during the later finer machining mode; moreover, the tool material can transfer to the workpiece surface during the compound process.

关 键 词：碳化硅陶瓷 电火花铣削 机械研磨 复合加工 扫描电子显微镜 复合过程 水基乳液 放电电流 

分 类 号：TG661[金属学及工艺—金属切削加工及机床] TQ174.758[化学工程—陶瓷工业]