The base study of laser machining compoind electrical discharges using coaxial method

• Main Authors: Pei-lun Huang, 黃培倫
• Other Authors: Chia-Lung Kuo
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/58981742686132645975

碩士 === 雲林科技大學 === 機械工程系碩士班 === 96 === Taiwan has played an important role in manufacturing mold around the world. General mold manufacture is processed through high-speed milling. However, due to the fact that some mold steel with high hardness easily wears the mill, and some small-diameter mills can not easily portray the micro features of the mold. Therefore, the technique of EDM is needed to assist the mold though the speed of EDM is slow, meanwhile the technique increases the processing cost. The research was made by applying hollow electrode in 1090nm Nd-YAG laser to proceeding laser plus EDM, and the aim was to increase the speed of EDM by using Nd-YAG. The research was conducted by using Hollow Pure Copper Electrode and Hollow Copper Tungsten Electrode as electrode materials, and stainless steel (SUS304) as basic materials. The research could be divided into three directions: Laser-Milling, EDM, and compound electrical discharges milling. In Laser-Milling, we discussed the effects of laser power, pulse wide, frequency, coaxial eject air and coaxial eject oxygen on laser-milling cutting width. In EDM, the effects of current, electrode materials, coaxial eject air, coaxial eject oxygen on EDM working efficiency. Through empirical experiment, we have found oxygen-assisted laser-milling or EDM can both highly increase the working efficiency and decrease the working burr. In the experiment of laser compound electrical discharges milling, we mainly discussed the feasibilities of Hollow Pure Copper Electrode and Hollow Copper Tungsten Electrode. After the experiment with the same working parameters, we have found as laser and EDM were processed synchronally would produce a melt pond temperature and the temperature was determined by the number of the working items. Take SuS304 as the example, the melt pond temperature was beyond 1500℃, which was far higher than the melt point of hollow pure copper electrode so as to wear the electrode fast. Therefore, it is more suitable to apply Hollow Copper Tungsten Electrode with high melt point in laser compound electrical discharges milling. Also, when hollow laser Copper Tungsten Electrode with coaxial eject oxygen was used to help process laser compound electrical discharges milling, the working efficiency was found to increase 30 times as much as that in traditional EDM in oil. Furthermore, the dimensional precision was better controlled than pure laser-milling.