线切割加工中钼丝振动主动控制的试验研究

Experimental Research on Active Vibration Control of Molybdenum Wire in WEDM Machining

分析快走丝电火花线切割机床加工过程中电极丝振动的产生机理，指出钼丝振动所反映的主要模态是原运动弦系统二阶以上的固有模态以及各种强迫振动模态。由试验所得的频谱图上看到，在线切割加工中钼丝振动的固有频率（高频）与走丝系统的其他振动频率（低频）是完全分离的，且低频振幅较大。由此得出控制丝振的关键在于抑制相丝的低频振动。提出丝振主动控制策略，机理性试验证明：施加主动控制后，丝振振幅为常规被动控制的十几分之一，同时也提高了其动态稳定性；进行了丝振控制多次切割试验，得到了振动频谱图，对控制前后的丝振频谱作了比较。

The mechanism of wire vibration in processing for high speed wire-cut electrical discharge machine(HS-WEDM)has been analysed.It is found from both analysis and experiments that the vibration of molybdenum wire in cutting process consists of mainly over the 2nd order natural modes of the moving wire and modes of various forced vibrations.The natural vibrations of the molybdenum wire are of high frequencies,the forced vibrations are of low frequencied with higher amplitudes.Therefore,low frequencies or forced vibrations dominate the dynamic stability of the molybdenum wire and the processing accuracy of the WEDM.For control of the wire vibration and improving the processing accuracy of HS-WEDM,active control is adapted,a control law and a control system are designed.Experiments have shown that by means of active control the vibration amplitude of the wire is less than one-tenth of that obtained by other passive control methods,and meanwhile the dynamic stability of the wire and the processing accuracy of WEDM are improved.In addition,the tests of multicutting with and without active control are performed and the frequency spectrum is obtained.