Effects of Grain Size and Ultrasonic Vibration on Micro Coining Process of Copper
| Autor: | CHEN, YI-CHIEH, 陳怡潔 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 The demand for the product miniaturization in many fields leads to enormous increases in research and development of manufacturing micro components in academia and industries. Micro metal forming is one of important processes for fabricating microscale metal components. However, the size effects may increase the influence of the grain size of metal and could cause issues on the material flows during the metal forming process at micro scale. This study investigated the effect of grain size and ultrasonic vibration on the coining process of copper at micro scale. The study employed annealing to adjust the grain size of pure copper. The average grain sizes of the wires from different treatments, the as-received, annealed at 580ºC and annealed at 800ºC, were 12.9 um, 63.8 um, and 154.1 um, respectively. The copper wires were then precisely machined as billets with 1 mm diameter and 1 mm height for the use in the experiments of the micro coining process under two forming conditions, with and without ultrasonic vibration. Moreover, the study also employed commercial finite element software to predict the load, deformation and die filling of the process. The results showed that grain size is an important factor affecting the micro coining process of copper. There is an improvement in the coined patterns for the cases with smaller grain size. Moreover, the ultrasonic vibration greatly affects the material flow and leads to better die filling, and significantly reduce the forming load. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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