Study on the magnetorheological finishing method for the WEDMed pierced die cavity

Abstract

The pierced die cavity manufactured by wire electrical discharge machining (WEDM) is difficult to be entirely polished. The current research proposed a new magnetorheological finishing (MRF) method for polishing the WEDMed pierced die cavity. When the pierced die cavity is fabricated, a core with the shape which perfectly fits the pierced die cavity is obtained simultaneously. The core is usually treated as waste, but the current research used the core as the polishing tool in MRF process. The magnetic field was provided to the core through two permanent magnets. Thus, when the core made a reciprocating motion occurring along the pierced die cavity surface in the magnetorheological finishing fluid, the pierced die cavity can be polished. With this method, the fabrication of special polishing tools for different cavities would no longer be needed; so, the production cost was saved and the production efficiency was improved. The magnetic field distribution in the gap between polishing tool and pierced die cavity was analyzed through simulation calculation, and the polishing effect was verified through experiment. The experimental results showed that the polishing effect on the corner of the pierced die cavity was not as good as that on the plane. The attempt of increasing the arc radius of the corner was conducted, and the results showed that the polishing quality improved with the increase of the arc radius of the corner.