Research On Performance Of Porous-electrode Electrical Discharge Machining

EDM with porous electrode was studied to overcome the conventional EDM tool electrode long preparation cycle, high cost and relatively low processing efficiency. Porous electrode by millimeter metal particle at high temperature sintering and porous electrode with the corresponding three-dimensional shape or profile of the bottom can be easily and quickly prepared by changing the shape of the mold block or end. Porous electrode with its distributed porous iner-flowing structure be able to achieve a higher efficiency of EDM as a result of the evacuation effect of flushing on debris.Rapid sintering process of the porous electrodes were studied by determining the materials, sintering mold and sintering method for the preparation of the electrodes in the sintering temperature, holding time and other parameters were studied experimentally, the preparation has been able to achieve stability EDM porous electrode useful. By scrapped after sintered porous electrode remanufacturing, recycling materials can be reached and the purpose of reducing manufacturing costs.The basic rules and processes of a porous electrode EDM machining mechanism were studied to explore the porous electrode EDM performance in a plane, deep, complex surface conditions.It was found that by compared with solid electrodes, the MRR by using porous electrode is lower when processing a shallow cavity. In deep cavity EDM processing, by using porous electrode and inner-flushing, tool lifting is not necessary. The machining efficiency can be improved, which is not influenced by machining depth. In order to investigate the mechanism of distributed flushing in porous-electrode Electrical Discharge Machining, Using the finite element method modeling and simulation of the gap flow field was carried out.The simulation results show that the velocity of the flow between electrodes has a distributed feature because of the distributed outlet, and the periphery velocity is larger than that around center. Internal flow channel of the porous electrode structure has carried on the simulation and optimization, and using the optimized porous electrodes were studied experimentally punch liquid parameters and processing performance relationship, the results showed that a tiny pulse interval can be applied and a high MRR is able to be achieved due to the high duty cycle. Experimental results also show that as the flushing flux increases, the MRR curve demonstrates a two peak-value characteristic, as a result of the dual roles of flushing on both debris evacuation and plasma channel disturbance.Experimental study was carried out on the difficult to machine materials, TC4 alloy and nickel base superalloy GH4169 porous electrode for EDM results show that Sincethe heat and debris generated by discharges was efficiently dispelled, so that it is not only available when processing TC4 high processing efficiency, tool electrode wear rate is also smaller, with smaller red liquid flow and currents in the processing of nickel-basedsuperalloy GH4169, can result in more high processing speed.Through a lot of the porous electrode sintering experiments and EDM experiment, a more comprehensive study of the preparation and performance of EDM machining mechanism and the porous electrode to achieve a rapid, low-cost preparation of large quantities of forming the electrodes confirmed porous electrode with high efficiency in the harsh environment of the material removal process capability, initially revealed the mechanism of the porous electrode EDM, but also proved that the porous electrode has broad application prospects in the field of difficult to machine materials.