PURPOSE: To provide local grinding of a work with high accuracy by furnishing a part where magnetic flux concentrates in a barrel to form a dense magnetic brush, and by allowing that portion of work which required precision grinding, to rotate either in regular or reverse direction within said dense magnetic brush in a specified angle range and at a certain angle speed.
CONSTITUTION: The boss We of a work W to be processed into an outer shell for a sewing machine etc. is held at the tip of a work retaining shaft 51. The work W is set in a barrel 30 and located between a bottom magnetic pole 41 and a top magnetic pole 43. When magnetic field is formed, the distribution of the flux in the barrel is dense in the range α in the attached illustration and coarse in the range β, so that magnetic brush by magnetic grinding material 61 has high density in α and low in β. In grinding operation, the barrel 30 is rotated either continuously, intermittently or in the reverse direction. At the same time, the work retaining shaft 51 is rotated in the regular or reverse direction at rotational angle according to the location and dispersion of the parts of work to be ground with high density and at an angle speed of specified pattern. Thereby the part Wa and its neighborhood are highly ground.
SUGAWARA SHUICHI
KAJI HISATSUGU
| JPS6034264A | 1985-02-21 | |||
| JPS58103890A | 1983-06-21 |