High aspect ratio circular micro-hole by micro-EDM

• Main Authors: Shih-Chieh Chou, 周士傑
• Other Authors: Yunn-Shiuan Liao
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/43877716250633039505

碩士 === 國立臺灣大學 === 機械工程學研究所 === 100 === Micro-EDM is a simple way of machining which is commonly used in conductive metal materials and widely employed in micro-hole drilling. However, when drilling to a certain depth, some difficulties pertaining to dielectric fluid entering the discharge gap and the remove of debris will arouse. Therefore the depth of micro holes is limited. In order to solve the difficulties confronted when dielectric fluid entering the discharge gap and the remove of debris, this study proposed a method of micro-hole drilling process based on micro electro-discharge machines with dielectric jet position and helix angle. A deeper micro hole can be achieved when above dielectric jet posi-tion drilling process and smaller helix angle electrode can achieve deeper and more circular hole. While machining micro holes with inclined-feeding and vibra-tion-assisted components in 10-degree-downward, vertical-feeding is almost tenth of inclined-feeding, causing the machined holes with ovality 50% on almost all three-axis platform. In order to solve the problem, this study proposed a method of a feeding-angle modified imputation Strategy. The ovality of a 10-degree-downward inclined feeding can be reduced to 8% and aspect ratio of 16 with cylinder electrode, and the ovality can be reduced to 0.2% and aspect ratio of 20.5 with 17-degree helix angle electrode.