Parametric Research on Flattening Process of Pure Copper Powders with Roller Equipment

• Main Authors: Bo-HengYo, 尤柏鑅
• Other Authors: Muh-Rong Wang
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/xb35n9

碩士 === 國立成功大學 === 航空太空工程學系 === 107 === Due to the quick development of human society, it causes the earth’s natural resources such as oil and minerals are almost been consumed. If we can obtain the useful substance by recycling waste, then the natural resource consumption rate can be reduced. Nowadays, natural resources in Taiwan are not enough to produce copper mines for refining. In the past, products made of copper are classified into following two categories: electric wires and copper alloy products. It is estimated that two-thirds of the refined copper was used to produce electric wires. This study will follow the concept of circular economy, the wasted electric cable is melted by gas atomization to produce spherical copper powder, then which is rolled into flattened morphology by the self-developed flattening device. Finally, the flattened powder applied to the multilayer ceramic capacitor. In this study, we use pure copper (purity 99.99%) as the experimental material to study the parameters of the roll flattening device, the effects of parameters such as powder feed rate, roller speed, roller line pressure on the characteristics of flake copper powder are discussed. The optimization parameter is based on the microstructure of flake copper powder and flattening ratio. Results show that the flattening ratio is 53.23%.,as the powder feeding rate is 48.8 g/min, roller speed is 10 rpm and the roller line pressure is 70 N/mm after four times rolling without adding any coolant like Ethanol. To prevent the copper powder from being cold welded to the roller surface during the rolling process, we conducted the experiment by adding ethyl alcohol on the roller at the same time when the roller line pressure is 130 N/mm, the flattening ratio is decreased to 23%.Althought the flattening performance is not better than the method without adding the coolant, the micrograph of the flake copper powder by the scanning electron microscopy shows the fine microstructure in the surface morphology, which is useful to produce the multilayer ceramic capacitor. Consequently, the rolling process can be used to reduce time and cost compared to the conventional ball milling.