| 摘要 |
PROBLEM TO BE SOLVED: To secure strength of a cutter body, rigidity and a back metal in a portion where a cutting edge forms a projection to maintain treatment accuracy, and prevent damage of the cutter body and the cutting edge, in particular, on a rear end side of a portion where the outer diameter is enlarged while the cutting edge is projected/recessed in a christmas tree-formed milling cutter. SOLUTION: A cutting edge part 3 provided with the cutting edge 4 projected/recessed at a plurality of stages in the radial direction with respect to an axial line O and having an outer diameter increased toward the rear end side in the axial line O direction is provided in an outer peripheral side edge part on a wall surface facing a cutter rotating direction T of a chip discharge groove 5 formed on the outer periphery of a tip part of the cutter body 1 rotated around the axial line O. In the cutting edge part 3, a core diameter tapered part 6 in which the diameter of a core diameter circle is gradually increased toward the rear end side in the axial line O direction is formed, and intervals H in the radial direction between the core diameter circle in the core diameter tapered part 6 and recessed bottom parts 7 at a plurality of stages recessed to the radial direction inner peripheral side of the cutting edge 4 are made approximately constant. COPYRIGHT: (C)2010,JPO&INPIT
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