| 摘要 |
PROBLEM TO BE SOLVED: To provide a rotating tool in which self excited oscillation (resonance) during cutting work is suppressed, whereby occurrence of chatter vibration can be remarkably suppressed.SOLUTION: At least four or more strips of chip discharge grooves 3 are formed on an outer periphery of a tool body 2, which is rotated around an axis O, with a clearance therebetween in a circumferential direction. In a cross-sectional view perpendicular to the axis O, a central angle, which is formed between a pair of virtual straight lines connecting each cutting edge 6 of cutting inserts 5, which are located in a pair of chip discharge grooves 3 adjacent to each other in the circumferential direction, and the axis O, is made to be an angle θ. In a cross-sectional view, in which among plural cutting inserts 5 arranged along the chip discharge groove 3, at least a first step cutting insert 5 positioned on an innermost side in the axis O direction appears, and in a cross-sectional view in which a second step cutting insert 5 appears, plural angles θ respectively formed around the axis O include one largest angle θmax, one smallest angle θmin, and two or more angles θ other than the largest angle θmax and the smallest angle θmin, respectively.SELECTED DRAWING: Figure 3 |
