往复走丝电火花线切割变厚度高效无烧伤切割研究

Research on Surface Burning of Reciprocating Traveling WEDM with Variable Thickness

针对往复走丝电火花线切割机床在变厚度高效切割时出现的切割状况不稳定、表面产生烧伤的问题,提出了一种基于放电状态检测的双重反馈调节控制方法。在第一重反馈时基于空载率等于短路率的原则调节伺服进给速度,保障切割稳定性;在第二重反馈时保障维持一定比例具有击穿延时的火花放电,以避免加工表面烧伤。结果表明:在本试验条件下,对于变厚度高效切割而言,双重反馈调节控制系统相较于峰值电压检测伺服跟踪方法,在无烧伤情况下的平均切割电流由5 A提高至7 A,切割速度提高24%,从而提高了往复走丝电火花线切割机床变厚度高效切割速度、表面质量和自动化水平。

Aiming at the problem of unstable cutting condition and surface burning in high efficient cutting of variable thickness by reciprocating traveling wire electrical-discharge machines,a dual feedback control method based on discharge state detection is proposed from the original servo feed system based on fixed threshold average voltage detection method. The first feedback is used to adjust the servo feed speed to ensure the stability of cutting,which was based on the principle of empty load rate equal to short circuit rate. The second feedback ensures that there is always a certain proportion of spark discharge with breakdown delay between anode and cathode to reduce surface burning. The experimental results show that,under the conditions of this experiment,the average cutting current can be increased from 5 A to 7 A and the cutting speed can be increased by 24% compared with the original method of fixed threshold average voltage detection for efficient cutting with variable thickness. The control system improves the cutting speed and automation level of reciprocating traveling wire electrical-discharge machines.