controlled efficiency of drilling with a high intensity beam

• Main Authors: Tzu-Chun Chao, 趙子鈞
• Other Authors: Peng-Sheng Wei
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/57dde8

碩士 === 國立中山大學 === 機械與機電工程學系研究所 === 101 === Drilling with a high intensity energy beam can beincapable if the keyhole induced is collapsed. In this work, we identify the conditions for the keyhole collapse during high power density beam drilling from fundamental principles of thermal physics. The approach adapted is to probe the supersonic flow behavior of the two-phase vapor-liquid dispersion in a vertical keyhole of varying cross-section, paying particular attention to the transition between the slug and annular flows. It shows that the keyhole collapse occur from entrainment around the keyhole wall resulting in a severely deformed wavy shape of the inner liquid surface of the keyhole. This work provides a critical investigation to reveal incapability of drilling encountered in materials processing, packaging and manufacturing technologies.