Development of Electroformed Ni-Co-based Magnetic Polishing Tools

Abstract

This study develops Ni-Co-based flaky magnetic polishing tools, which are made using an electroforming technique, to intensify the magnetic susceptibility of previously developed Ni-based flaky magnetic polishing tools. Vacuum heat treatment at 300 °C changes the mechanical properties of the Ni-Co-based flaky magnetic polishing tools. Although this resulted in an improvement over the former tools' performance, ferrous particles were required to assist in the internal finishing of SUS304 stainless steel tubes. Subsequently, Ni-Co-based flaky magnetic polishing tools containing WA abrasive (Ni-Co-WA magnetic polishing tools) were developed. Finishing experiments demonstrated that the subsequently developed tools achieved fine finishing without the assistance of ferrous particles and were superior to the only existing WA magnetic abrasive currently on the market. The lines of magnetic force flow normal to the target surface, and the Ni-Co-WA magnetic polishing tools are magnetized following the lines of magnetic force, thereby pushing the target surface with the edges of the polishing tools because of the magnetic anisotropy. Using vibratory motion parallel to the flat surface of the polishing tool, a single Ni-Co-WA flaky magnetic polishing tool showed feasibility to micro-groove finishing in addition to the internal finishing of the component.