3-flute ball end mill and 4-flute ball end mill

摘要

PROBLEM TO BE SOLVED: To provide a three-blade ball end mill capable of performing highly efficient machining to a hard-to-cut material and increasing its life.;SOLUTION: This three-blade ball end mill is provided with three spiral chip discharging grooves 2 directed to a base end side from a tool front end formed on the periphery of a tool body 1 and ball blades 5 respectively provided in the cross ridge line sections between the rake faces of these grooves 2 and the front end flank reliefs 4 of the tool body 1. The angle γ1 formed by a straight line passing the cross-point a1 of the ball blade 5 provided in the cross ridge line section between one front end flank relief 4 and the rake face of the groove 2 and a circle c1 with the 5% radius of the outer diameter of the tool around a tool rotational center O, and the tool rotational center O, and a straight line passing the cross-point b1 of the ridge line section 6 of the front end flank relief 4 on the rear side in the tool rotational direction positioned on the front side in the tool rotational direction of the ball blade 5 with the set cross-point a1 and the circle c1, and the tool rotational center O is set at 80°-115°.;COPYRIGHT: (C)2009,JPO&INPIT