Study On Machining Methods And Characteristics Of Multi-electrode EDM Using Capacitive Coupling Method

As we all know,low material removal rate and slow processing speed are one of the bottleneck problems restricting EDM,which greatly limits the development and further application of EDM.The reason is that electric discharge machining is discontinuous in time,because electric discharge machining must use pulse power supply intermittent discharge,and usually only discharge once per pulse cycle.Increasing the processing speed by reducing the discontinuous time,such as reducing the discontinuous time,has certain limitations,because a certain pulse interval must be ensured to ensure sufficient deionization between the poles.And by increasing the number of discharge points in each pulse cycle in space,that is,the multi-circuit EDM method has become one of the effective ways to solve the slow speed of EDM.To this end,this subject has conducted in-depth research on the multi-electrode EDM method based on capacitive coupling and its characteristics.In order to solve the problem that the discharge of one branch will cause the voltage of other discharge branches to decrease and reduce the probability of discharge during the processing of the existing capacitively coupled multi-electrode discharge circuit,this topic proposes a basis on the basis of analyzing its causes Capacitively coupled new discharge machining circuit.In this project,a simulation model of the charging/discharging process of multi-electrode discharge circuit processing was established.Multisim was used to simulate and compare the charging and discharging process and characteristics of the circuit structure under different discharge states before and after improvement,and the feasibility of improving the discharge circuit was verified.The effects of isolation feed capacitance,inter-electrode distance,processing area and compensation capacitance on the processing characteristics of the improved capacitively coupled multi-electrode discharge circuit were studied,which provided theoretical support for the next multi-electrode discharge process.Due to the single pulse discharge energy determination mechanism of the capacitive coupling power feeding method,theoretically,by increasing the pulse frequency,the EDM speed can be greatly improved.Therefore,this paper analyzes the implementation of the high-frequency square wave pulse power supply and completes the design plan,including MOSFET selection,drive circuit design,drive resistance selection,and protection buffer circuit design.In order to simultaneously detect the discharge state of the gap between the electrodes of the divided electrodes and realize the independent servo control of each electrode,an experimental platform for multi-electrode EDM machining was built.Finally,an experimental study on the characteristics of multi-electrode EDM based on capacitive coupling was conducted.The effects of pulse frequency,open-circuit voltage amplitude and servo reference voltage on the material removal rate and electrode loss of multi-electrode EDM were analyzed,and applied research was carried out.