Development of magnetic polishing method with 5-axis machining center for aspherical shape

摘要

In the fabrication of an aspherical mold, the workpiece is typically fabricated into the desired shape with a machining center, and the workpiece is polished using a polishing machine to obtain a smoother surface. Additionally, the mold fabrication process is "high-mix low-volume production," thereby significantly increasing the requirement for process integration. This paper proposes a magnetic polishing method that uses a small ball end-mill type tool on the machining center. In the polishing process of a mold, the form accuracy of the mold must be maintained. However, using the traditional loose-abrasive method results in the deterioration of form accuracy, because it is difficult to control the loose abrasives. In the proposed magnetic polishing method, the abrasives in a magnetic paste are controlled by a permanent-magnet tool, thereby making it feasible to maintain the form accuracy. Consequently, this study proposes a novel four-axis controlled magnetic polishing method to polish an aspherical mold, which uses a five-axis machining center. In this method, the contact position of the magnetic polishing tool is constantly maintained at all polishing points on the workpiece. Therefore, in order to obtain the effectiveness of the polishing force, this report proposes a novel polishing method that avoids the use of a tool center. The stainless steel (X30Cr13) was polished with the novel method and a general contour method. The novel method was able to polish the mold uniformly.