| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent chipping, etc., while maintaining size precision. SOLUTION: In a 1st grinding process for a 1st groove, the groove is ground by moving a rotary grinder 21 in a 1st direction 1 wherein it faces up at 45 deg. while rotated. In a 2nd grinding process for a 2nd groove, the groove is ground by moving the rotary grinder 21 in a 2nd direction 2 wherein it faces up at 45 while rotated. In a 3rd grinding process for a projection part formed at the intersection part between the 1st and 2nd grooves, the projection part is ground by moving a rotary grinder 22 which have finder grading than the rotary grinder 21 in a 3rd direction 3 wherein it faces horizontally while rotated.</p> |
