Study on a New Internal Finishing Process by the Application of Magnetic Abrasive Machining. Discussion of the Roundness

A mating part must have a smooth surface and an accurate form at the fitting area. When a new internal finishing process is utilized by the application of magnetic abrasive machining to internal finishing of hole of mating parts, it is necessary to clarify the effects of this finishing process on the form accuracy, such as the cylindricity and roundness. The effects on the cylindricity have been already reported, so that this paper discusses the effects on the roundness. Theoretical equations describing the roundness curve on the process are presented and experimentally proved. According to the equations, the roundness will be worsened with the finishing process. The rates of changes in the roundness curve before and after finishing are calculated less than 0.1% under the conditions used in the experiments. On the other hand, the changes in the roundness curve are observed in the finishing experiments of neither the clean pipes nor the workpieces with high form accuracy. These result in that the effects on the roundness are considered negligible under the conventional finishing conditions. Consequently, it is clarified that this finishing process has a characteristic to make the surface smooth with hardly changing the initial roundness curve.