| 摘要 |
<p>In cutting processes of a tree-shaped groove, in a rough cutting process, by using a rough cutting tool (20), as well as cutting a tapered groove (2), cutting is performed in a first narrow portion (11), a second narrow portion (12), and a third narrow portion (13) of a planned groove shape 10 such that a specified cutting allowance is left. In the following semi-finishing process, by using a semi-finishing tool, cutting is performed for portions other than the three narrow portions (11 to 13) that have already been cut. Because a work material 1 does not come in contact with three reduced diameter portions, of the semi-finishing tool formed in an upside-down Christmas tree shape, corresponding to the three narrow portions (11 to 13), a load is not imposed on the three reduced diameter portions, which are weak against shock among all portions of the semi-finishing tool, and the cutting feed can therefore be faster. Further, by performing a finishing process, the tree-shaped groove can be efficiently cut.</p> |
