大尺寸及异型锗窗高效电火花线切割技术

 研究了N型锗半导体电火花加工时所体现的单向导通性及特殊电特性，建立了电火花加工模型，分别用二极管、可变电阻、稳压管、电阻等器件表征了锗半导体与进电端材料的接触势垒、极间体电阻、介质放电维持电压及工作液电阻。设计了锗半导体电火花线切割专用夹具，采用锗半导体表面涂覆碳浆并用石墨块进电的方式以降低接触势垒、接触电阻，对进电接触点采用吹气方式减少电化学反应导致的不导电钝化膜的产生，保障加工的延续。最后对电阻率为22.3 Ω·cm，高度为170 mm的N型锗进行了电火花线切割，切割效率大于100 mm2/min，并采用数控的方法切割出异型锗窗。检测了放电波形，分析了锗半导体电火花线切割的特性。

Efficient Wire-cut Electrical Discharge Machine of Large-sized and Special-shaped Germanium Window

This article studies the unidirectional electric behavior and special electrical characteristics of germanium semiconductor cut in electrial discharge machine(EDM) processing. It establishes an EDM model and utilized respectively diodes, variable resistors, voltage regulator tubes, resistors and other devices to characterize the contact potential barrier, inter electrode bulk resistance, and discharge maintaining voltage of the dielectric and the resistance of the dielectric. In addition, it designes a special fixture for the wire-cut electrical disharge machine(WEDM) of germanium. By means of coating carbon plasma on the surface of germanium and meanwhile using a graphite block as an electrode, the contact potential barrier and contact resistance are reduced, and blowing at the electrical contact points reduced the production of non-conductive passive film to ensure the smooth performance of EDM. Finally, a WEDM experiment is carried out on an N-type germanium specimen with a resistivity of 22.3 Ω·cm and a height of 170 mm, with a cutting efficiency of more than 100 mm2/min, and a special shape germanium window is obtained by a numerical control machine. This article also testes the discharge waveform, analyzes the WEDM characteristics of germanium semiconductors.