Patent ID: 7101122

Claim:
A ball nose end mill comprising: a tool body having a distal end; and a throwaway insert mountable at the distal end of the tool body, wherein the throwaway insert comprises: a bottom face as a mounting face; an upper face on an opposite side from the bottom face; a side face formed between the bottom face and the upper face; and a cutting edge formed along an intersecting ridge between the upper face and the side face in a substantially arc shape such that the rotational trace of the cutting edge when the throwaway insert is attached to the tool body in use substantially forms a partial spherical surface, wherein an undulating portion, which is formed by alternately arranged concave portions and convex portions, is provided on the upper face so as to intersect the cutting edge, and so as to provide a wavy shape to the cutting edge, and wherein the concave portions comprise a first deep-concave portion, a shallow-concave portion approximate the first deep-concave portion, and a second deep-concave portion approximate the shallow-concave portion and opposing the first deep-concave portion, wherein the first and second deep-concave portions are deeper than the shallow-concave portion.