| 摘要 |
<P>PROBLEM TO BE SOLVED: To sufficiently secure strength of a periphery of a labyrinth groove LG of a metal component P. <P>SOLUTION: A ring groove G having a certain groove width along a groove depth direction is formed while recesses are provided on both sides of a tip of a dual-purpose cutting tool 20, groove walls Ga, Gc of the ring groove G are shaped in such a manner that the groove width increases outward from the side of a groove bottom Gb, while a recess is provided on one side of the tip of the dual-purpose cutting tool 20, and the groove bottom Gb of the ring groove G is rounded while recesses are provided on both sides of the tip of a groove bottom cutting tool 30. <P>COPYRIGHT: (C)2013,JPO&INPIT |
