| 摘要 |
PURPOSE:To improve a chip crushing characteristic, by changing the width of a cutting edge, divided by a nick, at random in the longitudinal direction further providing a positive clearance angle in the side of a major cutting edge of the cutting edge, in the case of an end mill which provides nicks (notches) in a plurality of the twisted cutting edges. CONSTITUTION:An end mill 1, respectively having four sheets of cutting edges 2 twisted at a predetermined angle, forms a twisted groove 5 between the neighboring cutting edges 2. Each cutting edge 2 provides over its whole surface with a predetermined space nicks 3 being cut so as to transversely divide the cutting edge 2. Here a width Y of the nick 3 is formed to a fixed value, while a width X of the cutting edge 2 divided by the nick 3 is changed under a fixed relation or at random over the end mill 1 from the point end of a tool to its root end. Further a flank 7 at an angle alpha is formed in at least the side of a major cutting edge of the cutting edge 4 divided by the nick 3. |
