Research On Key Technology Of Multi-station And Multi-axis NC-EDM For Closed Integral Impeller

“Electrical Discharge Machining (EDM)” is an importance technology innontraditional precision machining. Due to EDM can process complex anddifficult-to-cut parts and without cutting forces in machining, no glitches and ripplemarks and other defects. it is extensive used in processing of hard and fragility material,complex mold cavity, deep pores, and other measuring and manufacturing tools etc,especially in the field of highly complex, high-precision, low stiffness processing.Closed integral impeller is a typical example, especially titanium closed integralimpeller, which is difficult to shape and processing. According to analysis presented,we proposed a new method for processing of closed integral impeller, EDM. Then aspecial machine tool which is a multi-station multi-axis CNC EDM closed integralimpeller was designed.In this article, the main works are made as following:Firstly, the exiting processing craft and technical difficulties of closed (open)impeller were analyzed.Secondly, the analysis and research of firstly focus on CNC EDM machine closedintegral impeller, five-axis linkage machine tools, structure of shaping machine tool andthe problems of practical engineering. Though the analysis, the main problems of closedintegral impeller was given: low efficiency and high cost. Considering the features ofclosed integral impeller, multi-station, strong dedicated EDM machining tool wasdesigned, the efficiency is4~6times than the former. The simplified method ofcomplex surfaces for processing of multi-electrode linkage analog closed integralimpeller is also given.Thirdly, processing craft and electrode design method were improved. Methods ofrough machining of milling, craft of EDM finishing machining and electrode partitionand fitting program were proposed to solve problem of shape, thermal conductivity,narrow space of electrode movement and greatly reduce the number of electrodes.Fourthly, Pro/ENGINEER and CAD/CAM were used to3D solid modeling, motionsimulation. Then HyperMILL software was used to processing programming. Powerfulmulti-axis programming module of HyperMILL can optimize cutting feed and reducethe number of electrodes.This work is a project of innovative processing technology and innovativeequipment design. Aimed at resolving the problems of low efficiency and poor quality.Titanium alloy closed integral impeller machining was regard as the research object,analysis of closed integral impeller material characteristics and complex surface structure was presented. In order to resolve low efficiency of electric spark machiningand technical difficulties of electrode design, the special equipment was designed andprogramming simulation was given to conduct practical engineering and an ideal resultwas obtained which has a reference value in the closed integral impeller machining.