| 摘要 |
PROBLEM TO BE SOLVED: To provide an end mill capable of securing a large feeding amount in an axial direction and cutting with high efficiency.SOLUTION: An end mill comprises in an order from a tip end side: a cutting blade part 4; a neck part 3 having diameter which is smaller than outer diameter of the cutting blade part 4; and a shank part 2. An outer periphery of the cutting blade part 4 comprises: a chip discharge groove 5 which is twisted spirally with respect to an axial line O of the cutting blade part 4; and an outer peripheral cutting blade 6 formed on a side ridge part on the outer peripheral side of the chip discharge groove 5. When outer diameter of the outer peripheral cutting blade 6 is D, outer diameter of the neck part 3 is d, and when a cutting amount in a radial direction to the workpiece during processing is (D-d)/2, for processing, blade length L of the cutting blade part 4 in the axial direction is longer than length when a next forefront part starts cutting at a time point when a last end part of the outer peripheral cutting blade 6 in a spiral state finishes cutting, and is shorter than length when the next forefront part also finishes the cutting at a time point when the last end part of the outer peripheral cutting blade 6 finishes the cutting.SELECTED DRAWING: Figure 1 |
