Research On Machining Mechanism And Parameter Optimization Of Wedm Based On Ultrasonic Vibration

EDM wire-cut machining(WEDM)is a special machining method for material removal by pulsed spark discharge using continuously moving wire as electrode after machining.Because it can process the complex structure,with special requirements of the workpiece,so it is widely used in aerospace,military,electronics and other industrial fields.But with the continuous development of science and technology,the requirement of machining efficiency and machining quality of WEDM is getting higher and higher.Ultrasonic vibration assisted WEDM machining(UVWEDM)has positive effects on improving machining efficiency and surface quality,so it has attracted the attention of many scholars at home and abroad.At present,the research on ultrasonic vibration WEDM composite machining is mostly in the process of tool electrode,but the research on workpiece ultrasonic vibration is relatively lacking.And how to improve machining efficiency and surface quality is always the key research direction of composite machining.In this paper,the optimal machining parameter group to improve machining efficiency and surface quality in ultrasonic vibration EDM composite machining of workpiece is studied as follows:(1)Study on discharge mechanism of composite machining.The influence of ultrasonic vibration on WEDM machining is analyzed from four aspects: the discharge process,energy conversion,discharge of corrosion products and deionization.The impact of ultrasonic vibration on the removal volume of the pit was analyzed,and the theoretical model for machining speed and surface roughness is established.(2)Simulation of temperature field in composite machining.,Physicall and mathematical model are constructed base on composite machining,and an improved simulation model for the temperature field is developed.A heat flux model,based on a moving Gaussian heat source with ultrasonic vibration,is established.The influence of machining parameters on surface roughness is determined through finite element temperature field simulation results from ANSYS WORKBENCH,combined with the theoretical model formula for surface roughness.(3)Research on the optimization of conventional EDM machining process parameters.An experimental studies are carried out on a conventional EDM machine tool.By means of range analysis and variance analysis of orthogonal test,the optimal combination of machining parameters of machining speed and surface roughness and the influence of machining parameters on machining speed and surface roughness are obtained.(4)Study on the influence of ultrasonic parameters on process parameters in composite machining.A composite machining test platform was established and verified.The influence of ultrasonic parameters on machining speed and surface roughness and the enhancement rate of additional ultrasonic vibration on machining speed and surface roughness are studied.(5)Study on optimization of process parameters of composite machining.Based on orthogonal experiment,the optimization scheme of single objective process parameters is studied.The optimal combination of machining parameters and surface roughness in composite machining are obtained,as well as the main and secondary sequence and significance of the influence of machining parameters on machining speed and surface roughness.Based on the response surface method,the optimization scheme of multiobjective process parameters is studied,and the response surface model of optimization objectives and optimization parameters is established.The effectiveness and reliability of the response surface the majorization model of ultrasonic vibration WEDM process parameters are verified,and the final optimization results are determined.In this dissertation,the machining mechanism and process parameter optimization of wire-cut machining based on ultrasonic vibration are studied.Through the analysis of machining mechanism,the theoretical foundation is laid for the subsequent research of wirecut machining based on ultrasonic vibration.The optimization results of machining speed and surface roughness provide useful reference for parameter selection of improving machining efficiency and surface quality in practical machining.