Study of the EDM machining for micro-structure by combining RP technique with investment casting

• Main Authors: Ching-Se Hsu, 許靜色
• Other Authors: Chien-Chih Chen
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/34844705795717765321

碩士 === 龍華科技大學 === 工程技術研究所 === 100 === Electrical discharge machining (EDM) is one of the most extensively used non-conventional material removal processes. However, some electrodes are difficult to fabricate because of the complexity. Applying rapid prototyping (RP) technology to fabricate an EDM electrode prototype with investment casting, the cost and cycle-time can greatly be reduced. Investment casting is a method of producing high quality and complex metal shapes casting. The process has the advantages of reproducing complex shapes at relatively low cost, scalability from single items to large numbers of identical items, and low wastage of raw materials. The complex shapes electrode manufacturing process made by phosphor bronze alloy includes pattern assembly, slurry coating, stucco coating, pattern melt out, sintering, pouring, and shakeout, etc. This method was shown to finish the development of die-sinking EDM electrodes, shorten the electrode manufacturing process, decreased the manufacturing duration as well as the cost of electrodes. During EDM with distilled water, resolidification is very rapid at high temperatures and changes the microstructure of the machined surface layer. This layer is called the heat-affected zone. For comparison purposes, after EDM the hardness values of workpieces increases from HRC 8 to HRC 13. Additionally, the workpieces were etched by O2 plasma, it is apparent that the surface roughness could be decreased.