本篇論文之研究目的是建立一套能對於加工過後的模具在不破壞表面形貌的情況下再次進行表面粗糙度修整的精密拋光儀器,透過實驗與觀察了解新型磁流體拋光的拋光特性與表面品質的改善情況,並建立各參數對於表面粗糙度改善之關係。 根據實驗觀察,使用不同粒徑的四氧化三鐵、加工距離與轉速對於表面粗糙度的影響,對於新型磁流體拋光方式四氧化三鐵粒徑與加工距離影響最大,在各材料表面粗糙度的改善,以不破壞表面形貌的情況下,使用1µm氧化鋁作為磨料能將黃銅試片Ra降至18nm,無氧銅試片Ra降至27nm,無電解鎳試片Ra降至16nm,使用#8000 碳化矽做為磨料能將H13模具鋼試片Ra降至29nm,達到表面改善之目的,而新型磁流體拋光機台的架構簡單、加工方式簡單且成本低廉。
This research aims to build a preliminary magnetic abrasive polishing machine to polish various mold materials such as stainless steel, electroless nickel and OFCu. Ferromagnetic particles (Fe3O4) are homogeneously mixed with fine abrasive particles (Al2O3 or SiC) in this study to work as magnetic abrasive. The main polishing action is done by those abrasive particles trapped inside the ferromagnetic particles brush shaped by rotating electromagnet pole (magnetic field). Effort has been made to investigate the effect of abrasive particle size, ferromagnetic particles size, and gap between the workpiece and electromagnet pole on the achievable surface roughness. The results show that gap distance has very profound effect on the attainable surface roughness. Surface roughness (Ra) of 18 nm, 27 nm,16 nm and 29 nm are achieved on copper, OFCu, electroless nickel and stainless steel(H13) specimens respectively.