| 摘要 |
[Object] Providing a ball endmill that is capable of restraining its vibration thereby permitting a cutting operation to be performed at an increased feed rate with an increased depth of cut and leading to an improvement in efficiency of the cutting operation. [Measures for achieving the object] A ball endmill 1 is constructed such that each ball-nosed end cutting edge 6a-6c includes first, second and third portions 6a1-6c1, 6a2-6c2, 6a3-6c3 having respective first, second and third radii R1, R2, R3 of curvature which are different in value from each other. This construction causes a cutting resistance (cutting torque) exerted by the workpiece 20 to radially act in a direction that is different in the first, second and third portions 6a1-6c1, 6a2-6c2, 6a3-6c3 of each ball-nosed end cutting edge 6a-6c. Consequently, a feed rate and a depth of cut can be increased whereby the cutting efficiency can be improved. |
