Study on High-Aspect Ratio Microdrilling of a Thin Engineering Ceramic Sheet

• Main Authors: WU,MENG-CONG, 吳孟璁
• Other Authors: Chang,Dar-Yuan
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/fwak3a

碩士 === 中國文化大學 === 機械工程學系數位機電碩士班 === 105 === Engineering ceramic has excellent mechanical properties, such as high strength and stiffness in high-temperature, high strength-weight ratio, and capital resistances in corrosion and oxidation, which conforms to the requirements in semiconductor, electronic, aviation, and automobile industries. Its applications are growing in widespread; however, the machining of ceramic is difficult due to the hard-brittle feature. A hole with a diameter below 1mm made by mechanical machining is called Microdrilling. Semiconductor industry has the de has the demand of microhole pattern constructing by the holes under ∅100μm. This study conducts microdrilling experiments of a thin ceramic plate to explore the influences of drilling parameters on microhole quality characteristics machined. The fabrication of a microhole with high aspect ratio must perform by segmented machining. A center pilot hole is first made, and then uses a two-step drilling process to finish the hole. The drilling parameters analyzed include the depth of the pilot hole, length ratio of the segments, and the spindle speed, feed rate of the microdrill, depth of pecking drilling in the two-step drilling, to investigate the influences of these parameters on the quality characteristics of the microhole. Because the hole diameter of the top face and position errors of the top and bottom faces affect the functionality of the microhole pattern directly, this is a multipurpose problem by the three issues above mentioned. This study proposes a decision making method based on the factor level effects calculated to derive the optimal parametric level combination. Confirmation experiments have been done to verify the analytical results. In addition, this study also uses the SEM to inspect the flank wear of the drills for inspecting the effects of the number of drilling. This study has finished two series of Taguchi’s microdrilling experiments. The ratios of depth-diameter are 15.36 and 11.42, respectively. Experimental results show that after 600 holes process the deviation of diameter are controlled within 0.51~0.63μm, and that of the position error of the top and bottom faces are 0.29~0.98μm and 1.03~1.83μm, respectively. The drilling parametric set derived for thin engineering ceramic plate in this study has an excellent performance and the drills have also brought into a high efficiency.