Research On Detection Technology Of The WEDM Process Discharge Status

Wire cut electrical discharge machining(WEDM)technology as a kind of special machining method has been widely used in processing the difficult-to-machine material,parts required complex contours,special tools and mould manufacturing etc.,and which has played an important role in many areas of industrial production.In WEDM,precisely and real-time detecting the discharge status of electrical discharge machining can provide a reliable basis for control of servo feed and optimization of processing parameters.So as to maintain a good status of gap discharge,to achieve efficient and stable processing.Therefore,the discharge status of WEDM can be used as another important indicator to optimize machining parameters.There is a great significance for improving the machining accuracy and cutting speed to research on the high performance detection stability system of WEDM.In this paper,on the base of consulting a large of literatures,from the traditional threshold methods to artificial intelligence-based detection methods to detect the state of discharge were comprehensively analyzed.The current average voltage detection method ignores the details of a single pulse,this paper proposes the discharge status of real-time detection technology based on wavelet change to identify WEDM discharge status.In the analysis of WEDM discharge status,the partial open status and partial short status are proposed.A longer period of partial open pulses or partial short pulses may cause that the following pulses become open or short pulses,which will affect the processing.So detecting the partial open and partial short discharge status in WEDM will help to achievethe best control of electrical discharge machining.Clearly based on the wavelet transform theory,using of Hall sensors and high-frequency data acquisition card to complete the WEDM gap signal acquisition has been studied;digital signal logic processing has been built in Lab VIEW virtual platform and combined with selected hardware to build the stability detection system,which can effectively detect five kinds of discharge condition:open,partial open,normal spark,partial short and short.In WEDM,gap discharge coefficient Cgs can be an important parameter to measuring process stability.This paper have done the experiment about the effects of electrical parameters on the wavelet transform local maximum,and specific study of the pulse width,pulse interval ratio,short-circuit peak current impact of the wavelet local maximum.The waveform using oscilloscope synchronous sampling will be contrasted signal of detection system to verify detection system reliability.Finally,the application of the detection system in fluid roughing and liquid finishing,gas finishing and water mist finishing,it has been obtained the stability features of different media and spark rate distribution.