基于液相电极的微细电火花加工方法研究
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摘要
提出了一种利用液态金属作为加工电极的新型微细电火花放电加工方法,用于解决传统电火花加工中电极损耗引起的相关问题。该方法将导电的液态金属——镓铟锡合金注入毛细管工具电极中,通过控制管内压力使其悬挂在工具电极末端,脉冲电源施加在液体金属、工件之间,并控制它们之间的间隙来进行火花放电,从而达到蚀除工件的目的。放电过程中,尖端的液态金属会损耗,但在静电力以及虹吸作用下,工具电极中的液态金属会连续供应以补偿损耗。试验结果表明,镓铟锡合金能够作为电极进行电火花放电,任意图案扫描刻蚀结果表明镓铟锡合金电极进行电火花放电加工的方案是切实可行的,并且Parylene C镀层能够有效的保护工具电极。
Liquid electrode for Micro-electro-discharge machining is proposed and developed to address a variety of problems associated with electrode wear. An electrically conductive liquid metal alloy, Galinstan, is supplied through a metallic capillary nozzle such that the surface of the liquid is projected over the flat bottom of the nozzle. A discharge pulse generator is connected between the liquid(through the nozzle) and the workpiece. When the nozzle tip(covered by the liquid electrode) approaches the workpiece surface,it initiates discharge pulses when the gap meets the breakdown condition so that the generated pulses can thermally remove the material. During the machining process, a liquid electrode is continuously supplied to a metallic micro capillary nozzle to eliminate the impact of liquid consumption on the removal process. Experiments show that Galinstan, can be used as the electrode material to create discharge pulses and perform microscale removal on the samples. Controlled discharge generation and scanning-mode arbitrary etching are experimentally demonstrated using the Galinstan electrodes. It is also shown that a Parylene C coating is effective for protecting the nozzle from discharging.
Liquid electrode for Micro-electro-discharge machining is proposed and developed to address a variety of problems associated with electrode wear. An electrically conductive liquid metal alloy, Galinstan, is supplied through a metallic capillary nozzle such that the surface of the liquid is projected over the flat bottom of the nozzle. A discharge pulse generator is connected between the liquid(through the nozzle) and the workpiece. When the nozzle tip(covered by the liquid electrode) approaches the workpiece surface,it initiates discharge pulses when the gap meets the breakdown condition so that the generated pulses can thermally remove the material. During the machining process, a liquid electrode is continuously supplied to a metallic micro capillary nozzle to eliminate the impact of liquid consumption on the removal process. Experiments show that Galinstan, can be used as the electrode material to create discharge pulses and perform microscale removal on the samples. Controlled discharge generation and scanning-mode arbitrary etching are experimentally demonstrated using the Galinstan electrodes. It is also shown that a Parylene C coating is effective for protecting the nozzle from discharging.
引文
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[2]CHAVOSHI S Z,LUO X C.Hybrid micro-machining processes:A review[J].Precision Engineering,2015,41(7):1-23.
[3]SCHUBERT A,ZEIDLER H,KüHN R,et al.Microelectrical discharge machining:A suitable process for machining ceramics[J].Journal of Ceramics,2015,2015(1):1-9.
[4]OZGEDIK A,COGUN C.An experimental investigation of tool wear in electric discharge machining[J].The International Journal of Advanced Manufacturing Technology,2006,27(5):488-500.
[5]LIU Q,ZHANG Q,ZHANG M,et al.Review of size effects in micro electrical discharge machining[J].Precision Engineering,2016,44(4):29-40.
[6]ALIGIRI E,YEO S H,TAN P C.A new tool wear compensation method based on real-time estimation of material removal volume in micro-EDM[J].Journal of Materials Processing Technology,2010,210(15):2292-2303.
[7]YU H L,LUAN J J,LI J Z,et al.A new electrode wear compensation method for improving performance in 3Dmicro EDM milling[J].Journal of Micromechanics and Microengineering,2010,20(5):1-7.
[8]YU Z,MASUZAWA T,FUJINO M.Micro-EDM for three dimensional cavities-development of uniform wear method[J].CIRP Annals-Manufacture Technology,1998,47(1):169-172.
[9]NGUYEN V Q,DUONG T H,KIM H C.Precision micro EDM based on real-time monitoring and electrode wear compensation[J].International Journal of Advanced Manufacturing Technology,2015,79(9-12):1-10.
[10]YAN M T,HUANG K Y,LO C Y.A study on electrode wear sensing and compensation in Micro-EDM using machine vision system[J].International Journal of Advanced Manufacturing Technology,2009,42(11-12):1065-1073.
[11]ZHANG Y,KANG X,ZHAO W.The investigation of discharge restriction mechanism of the floating workpiece based electrostatic field-induced electrolyte jet(E-Jet)EDM[J].Journal of Materials Processing Technology,2017,247:134-142.
[12]ZHANG Y,HAN N,KANG X,et al.The tool electrode investigation of electrostatic field-induced electrolyte jet(E-jet)electrical discharge machining[J].International Journal of Advanced Manufacturing Technology,2016,82(5-8):1455-1461.
[13]HASSLER C,von METZEN R,STIEGLITZ T.Deposition parameters determining insulation resistance and crystallinity of parylene C in neural implant encapsulation[C]//4th European Conference of the International Federation for Medical and Biological Engineering(IFMBE),2009,2439-2442.
[14]YOON Y,KIM D,LEE J B.Hierarchical micro/nano structures for super-hydrophobic surfaces and super-lyophobic surface against liquid metal[J].Micro Nano System Letter,2014,2(1):3.