| Author Name | Affiliation | | Xin Mu | School of Mechanical and Electrial Engineering,Beijing Polytechnic University,Beijing 100176,China
School of Mechanical-Electronic and Automobile Engineering, Beijing University of Civil Engineering and Architecture, Beijing 102616,China | | Ming Zhou | School of Mechanical-Electronic and Automobile Engineering, Beijing University of Civil Engineering and Architecture, Beijing 102616,China | | Jun Zhang | School of Mechanical and Electronic Engineering, Beijing Institute of Graphic Communication, Beijing 102627, China |
|
| Abstract: |
| In electrical discharge machining of titanium alloys, the 1400-1600 ℃ melting points of titanium alloys require the input of sufficient discharge energy to melt and vaporize the titanium alloy. However, because of low thermo-conduction, the input energy can easily raise the temperature of the gap liquid to a high enough level. Usually, the elevated temperature of the gap liquid resulted in a reduction of the gap breakdown strength, so that the liquid dielectric deionization after pulse discharging tends to be incomplete and causes occurrences of large arcing pulses, burning the workpiece surface and causing electrode wear. This contradiction hinders the machining of titanium alloy by Electrical Discharge Machining (EDM). To solve this issue, this study thoroughly analyzed the factors influencing gap liquid breakdown strength during EDM and identified two key elements: gap distance and amount of chips left in gap. Based on this analysis, a solution was proposed, which involved the development of a multiple variable adaptive control system. This system adjusted the gap servo voltage in proportion to the gap distance to control the discharge types of pulses, regulated the electrode discharge time to the quantity of chips left in the gap in an electrode discharge time. By dynamically adjusting these two variables, the system maintained an optimal liquid breakdown strength, facilitating effective machining while preventing arcing in machining. Experimental validation confirmed that this multiple variable control system significantly enhanced the EDM process for titanium alloys, even under challenging conditions, demonstrating its practical utility. |
| Key words: electrical discharge machining adaptive control titanium alloy multiple variable control |
| DOI：10.11916/j.issn.1005-9113.25015 |
| Clc Number:v261.6 |
| Fund: |
|
| Descriptions in Chinese: |
| 多变量电火花自适应控制系统高效加工钛合金 穆鑫¹，²*，周明²，张军³ （1. 北京科技职业大学 机电工程学院，北京 100176； 2. 北京建筑大学 机电与车辆工程学院，北京 102616； 3. 北京印刷学院 机电工程学院，北京 102627） 摘要 在电火花加工钛合金过程中，由于钛合金的熔点为1400－1600℃，因此需要输入足够的放电能量以熔化钛合金。然而，由于钛合金的导热性低，输入的能量很容易使间隙介质的温度升高到足够高的水平。通常，间隙介质温度升高会导致间隙击穿强度降低，从而使脉冲放电后的介质消电离不充分，造成有害放电脉冲的产生，进而烧伤工件表面并引起电极损耗。这种矛盾阻碍了电火花加工（EDM）技术对钛合金的加工。为解决这个问题，本研究深入分析了在电火花加工过程中影响间隙介质击穿强度的因素，并确定了两个关键因素：间隙距离和间隙中残留的废屑量。基于这一分析，提出一种解决方案，即开发多变量自适应控制系统。该系统根据间隙距离调整间隙伺服电压，以控制脉冲类型，调节电极放电时间以适应间隙中残留废屑的数量。通过动态调整这两个变量，系统保持了最佳的介质击穿强度，从而实现高效加工并防止加工中的拉弧发生。实验验证表明，该多变量控制系统显著增强了电火花加工钛合金的稳定性，即使在具有挑战性加工环境的条件下，也展示了其实用价值。 关键词：电火花加工；自适应控制；钛合金；多变量控制 |
