Patent ID: 6953310

Claim:
A cemented carbide ball end mill comprising: a cutting portion having a semi-spherical ball portion at a tip thereof, at least one cutting edge formed along an outer periphery of the end mill inclusive of the ball portion, and a chip evacuating flute adjacent to the cutting edge, wherein when an intersection line between a rake face of the cutting edge and a chip evacuating flute at the ball portion is projected on a plane which includes a central axis of the cemented carbide ball end mill and is parallel with the cutting edge at a central portion of a tip of the ball portion, the intersection line projected on the plane is a convex-curved line, an angle formed by a straight line connecting a vertex of the ball portion, where the intersection line passes through, and an other end of the intersection line with respect to the central axis is from 30° to 50°, in a plane perpendicular to the intersection line, an angle formed by the rake face and a straight line portion at bottom of the chip evacuating flute is in a range of 100° to 150°, and in the perpendicular plane, a width of the bottom straight line portion of the chip evacuating flute with respect to the perpendicular plane is 0.5 to 5 fives as large as a radius of the ball portion.