End mill having a symmetric index angle arrangement for machining titanium

摘要

An end mill for machining titanium includes a cutting portion having blunt cutting edges alternated with flutes. Each flute includes, in order from the cutting edge, a rake surface, a concavely shaped bending portion, a convexly shaped ejecting portion and a tooth relief edge. The convexly shaped ejecting portion has an ejection height E, which is measurable between an apex of the ejecting portion to an imaginary straight line extending from a nadir of the adjacent bending portion of the flute to the adjacent tooth relief edge. In a plane perpendicular to a rotation axis of the end mill, the ejection height E and a cutting portion diameter DE, fulfill the condition 0.010DE

主权项

1. An end mill for machining titanium, having a longitudinally extending rotation axis AR and comprising:
a shank portion, and a cutting portion extending from the shank portion to a cutting end face and being integrally formed with at least four cutting teeth alternated with helically shaped flutes and having a cutting portion diameter DE; each tooth comprising a rake surface, a relief surface, a cutting edge formed at an intersection of the rake and relief surfaces, and a relief edge spaced apart from the cutting edge and formed at an intersection of the relief surface and an adjacent surface of the flute succeeding the tooth; each rake surface comprising a rake recessed sub-surface, a rake cutting sub-surface positioned further than the rake recessed sub-surface from the rotation axis and raised above the rake recessed sub-surface, relative to an imaginary radial line passing through the cutting edge, and a rake discontinuity formed at an intersection of the rake recessed and rake cutting sub-surfaces; wherein each tooth comprises an actual internal cutting angle formed at an intersection of the rake cutting sub-surface and the relief surface, the actual internal cutting angle having a greater value than an imaginary internal cutting angle formed at an intersection of imaginary extension lines of the rake recessed sub-surface and the relief surface; wherein, in a plane perpendicular to the rotation axis AR, each flute comprises a convexly shaped ejecting portion and a concavely shaped bending portion connecting the ejecting portion and the rake recessed sub-surface; wherein the ejecting portion has an ejection height E which is measurable between an apex of the ejecting portion to an imaginary straight line extending from a nadir of the adjacent bending portion to the adjacent relief edge, the ejection height E having a magnitude fulfilling the condition 0.010DE