Research On High Efficiency Of Multi-cutting In High-Speed Wire Electrical Discharge Machining

With the rapid development of manufacturing industry,higher requirements are put forward for WEDM,and improving the efficiency of HS-WEDM multiple cutting has become one of the most important research directions.The main way to improve the efficiency of HS-WEDM is to increase the discharge energy of the main cutting,but after increasing the main cutting energy,because of the abnormal state between the poles,the subsequent repair can not be carried out normally.In this paper,the basic theoretical analysis and Technological Test Research on the realization of HS-WEDM are carried out.The main work is as follows:(1)Aiming at the problem of burn on the surface of workpiece when the main cutting current increases,the causes and influencing factors of burn are analyzed.Starting from reducing burn,the limit burn current value of current working fluid is found by improving working fluid and adjusting electric parameters;(2)In view of the problem that increasing the main cutting current will attach a large number of erosion products on the surface of the workpiece,which makes the discharge of the repair cutter unstable,this paper analyzes the reasons why the erosion products affect the processing stability,and adopts the"cleaning"process.Firstly,this layer of erosion products adsorbed on the surface of the workpiece is removed,so that the discharge of the subsequent repair cutter can be carried out stably;(3)In view of the problem that the vibration of electrode wire increases in the process of tool repair after increasing the current of tool repair,the vibration model of electrode wire discharge area is established,and the influence of the increase of electrode wire vibration on the process of tool repair is analyzed.It is concluded that the reciprocating wire tension of heavy hammer tension mechanism is uneven,so it is not suitable for tool repair with high current.In the final experiment,the closed-loop constant tension mechanism is used instead of the heavy hammer tension mechanism to ensure the constant tension of the electrode wire and the high current high-efficiency repair of the knife;(4)According to the new requirement of high current and high efficiency repair cutter for power supply formation,that is,the main cutting can generate more current and repair cutter can form enough erosion amount under high-speed feed,through improving the whole power supply hardware signal transmission and power device,selecting high-speed power device and reducing the distribution time of pulse transmission circuit,the hardware part can have faster response speed and improve The pulse discharge frequency ensures that the cutting tool can be repaired at high speed and the comprehensive efficiency can be improved;(5)In order to ensure reliable power supply and avoid the problem of broken wire at the power supply point,the traditional contact power supply is replaced by the compact power supply,so that the electrode wire at the power supply point is not easy to shake and produce broken wire;(6)Finally,the comprehensive efficiency?133mm~2/min,surface roughness Ra=1.6?m,comprehensive efficiency?105mm~2/min,surface roughness Ra=1.4?m were obtained.Compared with the traditional method,the comprehensive efficiency is improved by 50%,and the surface roughness Ra of multiple cutting is improved by 20%.