| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a spark plug capable of restraining eccentricity or axial shift at a hole part of a molded body generated at the time of grinding of the molded body into a shape of an insulator after molding the molded body with raw material powder. SOLUTION: In a manufacturing process of an insulator constituting the spark plug, a molded body 30 molded from raw material powder is put under a grinding process into a shape corresponding to the insulator. In the grinding process, the molded body 30 is made in contact with a rotating roller for grinding 35 under rotation or the like, and at the same time, is made in contact with a rotating roller for pressing 37 or the like, so that grinding is carried out by supporting the molded body 30 against frictional force received from the rotating roller for grinding 35 or the like. At this time, a position S1 where the rotating roller for pressing 37 or the like comes in contact with the molded body 30 is shifted from a position S2 where the rotating roller for grinding 35 or the like comes in contact with the molded body 30 by a given angle A larger than 180°and smaller than 270°in a rotation direction F1 of the molded body 30. COPYRIGHT: (C)2007,JPO&INPIT
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