Study On The Effects Of Powders On Powder Mixed EDM

Powder Mixed Electrical Discharge Machining (PMEDM) is a relatively novel machining method which could enhance the surface quality of the workpiece and the efficiency of the finishing machining through the facilitation of the discharging stability, depending on adding powder particles who have the property of the electric conduction, such as the silicon and aluminum powder, into the working fluid (such as kerosene). It may effectively relief the confliction between the electric area and the surface quality during the machining process, and also could improve the properties of the workpiece surface, thus PMEDM has a great potential in the polishing machining, especially the large area polishing machining of the mold cavity. Therefore, PMEDM raises more and more concerning in the industries of aerospace, automobile and precise mechanical manufacturing.The mechanism concerning about the EDM machining process is very complicated, the size and characteristics of suspended powder particles change the dielectric properties of the working fluid, thus it affects the machining mechanism of EDM. In order to study the mechanism how the addition of powder particles affect the discharging breakdown, the work of this thesis focuses on the studying of the mixed powder-working fluid system, analyzes the mechanism of the electrode erosion and the appropriate solution in reducing the erosion. This may promote the application of PMEDM and its practice. In the mean time, it may also benefit the study of PMEDM in broad, decrease the machining cost of this kind of machining process.This thesis mainly focuses on studying the following perspectives of PMEDM:1 .In order to satisfy the versatile demand of the powder particle materials, the principle how various kinds of powder particles affect the surface quality of the workpiece machined by the MPEDM is studies in the thesis; And then the thesis also presents how the density of powder particles affect the processing characteristics through changing the density of aluminum powder particles in the working fluid, and mentions that it will be a great help to improve the surface roughness of the workpiece and enhance the removal rate when the density of powder particles is kept in an appropriate range.2. When it comes to different materials of the workpiece, the micro-profile of the surface of the workpiece machined by PMEDM is analyzed. The thesis also presents a relatively novel construction of powder particles, and through the analysis of mechanism about the aggregation of powder particles, and mentions some measures for avoiding the aggregation. It offers the theoretical support in the perspective of initiative development of novel powder particles which is more committed to the demand of PMEDM on some degree.