BALL END MILL WITH CYLINDRICALLY-FACED TWISTED CUTTING EDGE AND CONED TWISTED CUTTING EDGE OF LARGE TWISTING ANGLE AND LARGE RAKE ANGLE

摘要

PURPOSE:To completely prevent cutting edges from being damaged for almost all the required shapes by conveniently selecting a rake groove of a propor shape, in a ball end mill with cylindrically-faced twisted cutting edge and coned cutting edge of large twisting angle and large rake angle. CONSTITUTION:In the spherical cutting edge of a ball end mill with a cylindrically-faced twisted cutting edge 101 or a coned twisted cutting edge of large twisting angle and large rake surface, it the constant point 109 of this edge tip with the cylindrically-surfaced twisted cutting edge is made a reference, the angle of elevation, the angle of longitude or the direction angle and, the twisting angle of the twisted edge at the contact point are expressed as alpha, beta and gamma respectively, beta=tangamma, F(alpha), F'(0)=1, and F'(alphap)=0, or very small, being positive; similarly within the range of alphapalpha90, F'(alpha)=0 or very small, being positive, and the spherical cutting edge is so provided as able to be expressed with the function F(alpha), including tangamma, as parameter, which does not cause the edge to be damaged at the rearest end, in the rotational direction of a rake groove with a large rake angle of the cylindrically-faced twisted cutting edge 101.