Internal finishing of capillary tubes by magnetic abrasive finishing using a multiple pole-tip system

Due to difficulties in controlling magnetic abrasive in the finishing area during internal magnetic abrasive finishing (MAF) of capillary tubes, the finished length is limited in practice to just a few times the pole-tip width. The accumulation of multiple short finishing passes is necessary for long-tube finishing, which results in excessive finishing times. The use of a multiple pole-tip system with a tool, a solid rod consisting of alternating magnetic and nonmagnetic regions, was proposed to overcome this issue. The tool enables multiple finishing regions to be engaged simultaneously. This paper clarifies the finishing characteristics and mechanism and shows the effects of the tool's magnetic properties (including the intervals between magnetic and non-magnetic regions) on the tool and abrasive motion and the interior finishing characteristics of capillary tubes. This paper also proposes a simple method to determine the pole-tip feed length, which allows the MAF process to achieve a uniformly finished surface in half the time of the existing single pole-tip system.

► Propose a multiple pole-tip system using a metastable austenitic stainless steel tool by magnetic abrasive finishing.
► Explain processing principles.
► Clarify the finishing characteristics and mechanism of multiple pole-tip system.
► Demonstrate pole-tip feed length and surface roughness uniformity.