Process Research On High-speed Small Hole Drilling By EDM Combined With Magnetic Field And Water Dispersant

The EDM makes use of the pulse spark discharge between the two-pole in the isolation medium to produce electrical corrosive effects to remove metal and change the material size and shape, small hole EDM drilling is one of the main ways of micro holes machining and applied very widely. But machining efficiency of the small hole drilling EDM is relatively low and work instability, especially when the depth of the hole beyond a certain value, particles can not be effectively removed and fresh dielectric fluid is unable to enter the gap, the shortcoming is more obvious because of chip-ejection difficulty, Secondary discharge caused by chip-ejection difficulty not only makes the material elimination rate drop, but also causes form and position err of processing hole and then affects product performance.In order to improve processing efficiency, to overcome the above-mentioned bottlenecks, The Theory of high-speed small hole drilling by EDM combined with magnetic field and water dispersant has been introducted on the basis of EDM for the first time. The corresponding experiments were conducted based on theoretical analysis.The main works in this dissertation are as follows:(1) EDM and electromagnetic technology are combined, the Theory of electromagnetic force, magnetization force and the property of magnetic field on the plasma oscillations helpful to chip removal was analyzed in detail(2)The performance of dispersing agent in high speed small hole drilling by EDM are analyzed in detail. Mechanism on dispersing agent helpful to chip removal are discussed deeply, this conculusion lays foundation for put the dispersant into the process of the small hole drilling by EDM.(3)The performance of the two types of dispersants(PAA,TH-3100) are analyzed by contrast.Ultimately choose TH-3100 through the result of the experiment,because of the better effect on EDM.(4) the common effect of dispersing agent and magnetic field on EDM were considered and the EDM combined with magnetic field and water dispersant is beneficial to the chip removal and increase the efficiency were confirmed(5) The characteristics of flow field are important factors affecting MRR and the machining stability.This dissertation attempts to simulate the liquid flow field in discharge gap for High-speed Small hole Drilling by EDM combined with magnetic field and water dispersant by the software FLUENT, which simulate the turbulence intensity, pressure distribution velocity distribution, temperature distribution of the gap flow distribution and the motion trail of the electrical erosion particles under the influence of these factors. Analysis on the factors which influence the processing quality of EDM by comparing with the small hole drilling by EDM combined without magnetic field and water dispersant,.(6) EDM combined with magnetic field and water dispersant based on the theoretical analysis were experimental researched by comparing with the small hole drilling by EDM combined without magnetic field and water dispersant, The experiments results show this method could greatly improve the material removal rate and the processing quality of the hole, significantly decrease the tool wear rate.(7) The research on adding different concentration of the dispersant in high-speed small hole EDM drilling assisted by magnetic field and adding dispersing agent were conducted based on theoretical analysis, which in order to find the best of the moisture powder concentration ratio.Above all, a lot of research on the EDM combined with magnetic field and water dispersant according to theory were conducted,And the influence of improving elimination of debris on the machining speed, workpiece surface quality and electrode relative-wear are researched,which has important academic and practical significance toward the development of EDM.