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管电极电解加工监控系统的设计及试验研究

Design of Monitoring and Control System and Experimental Research on Shape Tube Electrochemical Machining

【作者】 谢文清

【导师】 朱荻;

【作者基本信息】 南京航空航天大学 , 机械制造及其自动化, 2009, 硕士

【摘要】 电解加工具有加工效率高、加工表面质量好、工具无损耗等优点,在航空、航天、兵器等国防工业生产中得到广泛的应用,但是它还存在一些问题,如火花短路、杂散腐蚀等。本文研究小孔管电极电解加工工艺,完成的主要工作如下:(1)在电解加工机床的基础上,构建出管电极电解加工的试验系统,它包括供液系统、运动控制、数据采集及处理、电路通断控制等部分。(2)研制了单孔和群孔管电极电解加工的监控系统。通过对加工电流信号的实时监测,设计了常规恒速进给、短路暂停进给、短路回退等三种响应方案。试验结果表明短路回退方案最有利于提高加工稳定性。另外,通过分析整个加工过程的电流信号规律和孔出口处的杂散腐蚀现象,设计了加工电流作为反馈信号的方案,从而有效降低了孔出口处的杂散腐蚀。(3)研究了进给速度、电解液压力、绝缘层厚度等参数对加工稳定性的影响,以及加工电压、进给速度、电解液浓度等参数对群孔侧面加工间隙的影响,试验结果表明优化加工参数不仅可以提高小孔加工的稳定性,还有利于减小侧面加工间隙,提高加工的定域蚀除能力。

【Abstract】 Electrochemical machining (ECM) is widely used in manufacturing of aviation and weapons because of its advantages such as high productivity, high superficial quality, and no spoilage on the machining tool. But it also has some disadvantages, such as spark short circuit, stray corrosion, etc.In this paper, shape tube electrochemical machining (STEM) is investigated to process small hole. The following work has been done:(1) Based on the machine tool, a experimental system has been developed which consists of electrolyte, motion control, detection and analysis of experimental date, circuit control.(2) The monitoring and control systems of processing single hole and group holes are developed. Based on monitoring current signal, three different response methods, which include feeding at constant speed, short circuit pause, and short circuit back feeding, are designed to control inter-electrode gap. The experimental results indicate the last method is best to improve the processing stability. In addition, after the current signal on the whole processing hole and the exit stray corrosion are analyzed, a response method is designed to decrease the stray corrosion.(3) The influence of process parameters, such as feed speed, electrolyte pressure, and insulation thickness of electrode on stability of processing small hole are investigated. And the influence of process parameters, such as machining voltage, feed speed, concentration of electrolyte on the radial overcut of group holes are also investigated. The experimental results indicate that optimized processing parameters can not only improve the processing stability, but also reduce the radial overcut.

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