Research On Liquid Metal Electrode EMD Based On Parallel Electric Field

With the development of technology and the application of industrialization,the demand for micro-small parts is increasing fleetly in the area of precision medical equipment,aerospace,optical and electronic communication and other fields.Micro-EDM technology has shown great advantages in the field of micro-small parts processing because of its non-contact processing,no obvious mechanical cutting force,wide applicability of processing materials,and low requirements for strength and hardness of tool electrodes.Therefore,micro-EDM has shown great potential in the field of micro-small parts processing and has attracted widespread attention.It has gradually become one of the key technical means for the precision manufacturing of micro-small parts,and has a large number of irreplaceable functions.When the finer parts processed by micro-EDM,the finer tool electrodes are required.However,the preparation of the fine electrode is very difficult,and the electrode wear is inevitable in the process of discharge machining,which affects the machining precision and limits the further development and application of the micro-EDM.Aim at the problem of electrode wear in micro EDM,a new type of EDM technology with liquid metal as electrode is used in this thesis.On the one hand,it reduces the need for preparation of fine electrodes.On the other hand,it solves the problem of electrode wear in micro-EDM through the fluidity of liquid metal.At present,the linear groove width of the workpiece processed by the metal electrode EDM can generally reach the level of three hundred to five hundred micrometers,but this is far from being able to meet the precision requirements.In order to improve the machining accuracy of liquid metal,a method of using parallel electric field to assist the liquid metal electrode EDM is proposed in this thesis.Through the auxiliary action of the electrostatic field,the terminal of the liquid metal electrode in the process is restrained and controlled to improve the precision of the liquid metal electrode EDM.In order to analyze the effect of parallel electric field on the machining accuracy of liquid metal electrode EDM,the electric field strength at the terminal of the liquid metal electrode was analyzed,and the COMSOL,a numerical simulation software,was used to model the terminal of liquid metal electrodes and to simulate the additional parallel electrostatic field.It was found that the additional parallel electric field has a certain constraint and control effect on the liquid metal terminal.To further verify the practical auxiliary effect of parallel electric field,the experimental platform of three-axis precise motor is built,and the movement control of the platform was realized through programming.And then the corresponding experimental research on liquid metal electrode EDM with electric field was carried out on the established machining experimental platform.The experiment used an RC pulse generator of approximately 100 V,a 0.1?F capacitor and a 500? resistor.The non-conducting coated needle with liquid metal was used as the tool electrode for electrical discharge machining experiments.The experimental results show that the liquid metal electrode EDM with additional parallel electric field can improve the machining accuracy within a certain range.It also proves that EDM of the solid electrode with additional parallel electric field can not improve the machining accuracy.