| 摘要: | 螺旋研拋加工法是一種利用高速螺旋迴轉傳遞磨料進行拋光的技術，當螺桿高速旋轉時，磨料將順著螺桿的螺旋溝槽朝上移動，被傳動之磨料直接高速研磨接觸被加工件，運動行程較傳統磨粒流拋光方式行程長而達到表面均勻拋光作用，因本加工法之磨料具有循環作動功能，磨料成本低且消耗量少，可獲得『低成本』、『快速』且『有效率』去除毛邊、變質層等功能，達到被加工件『快速精拋』的加工效果。
本研究將磁力研磨拋光與螺旋研拋法相結合，利用磁力研磨拋光的磁力加強螺旋研拋加工時的加工力，改善游離磨料加工時加工力較弱的缺點，增進研磨拋光加工時的效果。磨粒在螺旋研拋加工法扮演舉足輕重的地位，本研究自行開發新型磁性磨粒，在磨粒表面披覆一層磁性粒子，使之具有磁性磨粒的功能，再者利用磨粒中高分子粒子的彈性，減低磨粒撞擊工件表面時所產生的撞擊能，有效吸收過大的衝擊力，減少過度加工的作用。將之應用在不鏽鋼內圓孔之表面研拋，由實驗可得在磁通量密度90mT、碳化矽粒徑4μm、矽油黏度2000mm2/s、磁性磨粒濃度60%、加工間隙0.6mm及主軸轉速4000rpm之加工參數，可於20分鐘內將表面粗糙度Ra由0.9μm大幅下降到0.0541μm ，改善率達到94%，可明顯縮短拋光時間並得到極佳的表面加工效果。
;Spiral polishing mechanism is the technology of employing a high-speed turning screw rod to drive the abrasive to achieve the purpose of polishing the workpiece surface. The fast-turning screw rod drives the abrasive to move upward along the groove of the rod to keep polishing the workpiece in a recycling movement. Compared with traditional polishing methods, the long moving path of the abrasive helps achieve better polishing quality. Besides, the recycling movement of the abrasive not only effectively reduces the cost and the quantity of abrasive, but also removes the burrs in a fast, efficient, and economical way. Therefore, it is a superior method to reach good machining effect.
In this study, the magneto-assisted polishing was combined with spiral polishing mechanism. With the magnetism employed in the magneto-assisted polishing, the polishing force of the abrasive in spiral polishing was enforced and thus the polishing effect was improved. Actually, the abrasive played a crucial role in spiral polishing mechanism. In the present study, a new kind of magnetic abrasive was developed by coating each particle with a layer of magnetic particles. Moreover, the elasticity of the abrasive eased the kinetic energy generated from the polishing process on the workpiece surface, with the function of reducing the great impact during the polishing and preventing the effect of over-polishing. When this technology was applied to the polishing of the inner wall of the bore, the results of the experiment showed that with the parameter variables of magnetic flux density of 90mT, Sic size of 4μm, Silicone oil viscosity of 2000mm2/s, magneto-elastic abrasive concentration of 60%, machining gap of 0.6 mm , and the spindle revolution speed at 4000 rpm, the surface roughness (Ra) was lowered from 0.90 μm. to 0.0541 μm. in 20 minutes, at the improvement rate of 94%. The polishing time was significantly shortened and the optimal polishing effect was obtained. |
