| 摘要 |
PURPOSE:To enable a wave-shaped pitch groove to be correctly further promptly cut, by cutting the pitch groove while rotating a rolling roll synchronously with a movement of the swiveling center of an end mill in a predetermined locus with respect to the center of a caliber. CONSTITUTION:An end mill 34, forming in its edge point a chamfering part, is swiveled about the center P of a caliber 9 serving as the swiveling center by a swivel bed 29, and the end mill 34, while a rolling roll 11 is rotated synchronously with the movement in a predetermined locus with respect to the caliber center, cuts a wave-shaped pitch groove 33C in the whole unit of the caliber 9 in the first cutting process. Next, the end mill 34, while moving its swiveling center in a predetermined locus with respect to the caliber center, cuts a folded part of the pitch groove 33C, left as not cut, to be removed, and the end mill, being swiveled at a predetermined angle about the caliber center serving as the swiveling center to be quickly fed in the pitch groove 33C and repeating the action with a process rotating the rolling roll 11, cuts a folded part of the pitch groove to be removed as the second cutting process. In this way, the wave-shaped pitch groove can be correctly cut. |
