Study on a New Internal Finishing Process by the Application of Magnetic Abrasive Machining : 2nd Report, Effects of Magnetic Field Distribution on Magnetic Force Acting on Magnetic Abrasives

Abstract

This investigation examines the requirements for realizing high-efficiency finishing in a new internal finishing process by the application of magnetic abrasive machining. In this process, a magnetic force is generated between magnetic abrasives which is supplied to the inside of the tube and to the magnetic poles located around the outside of the tube ; this controls the finishing characteristics. Two factors may increase the magnetic force : (1) volume and magnetic susceptibility of the magnetic abrasive and (2) magnetic field distribution. We discussed factor (1) in our first report. The present report is concerned with factor (2). With regard to (2), the magnetic force can be increased by the enhancement of the magnetic field strength and its gradient over the finishing area. It was found that by increasing the excitation current, tapering the magnetic pole tip, and minimizing the clearance, the magnetic field strength and its gradient can be increased ; this leads to the increase in the magnetic force. It was also verified that the high magnetic force leads to high-efficiency finishing.