Milling insert and milling tip-replacement-type rotary cutting tool

摘要

A milling insert includes a polygonal tubular insert body which has: rake faces on one polygonal surface thereof, flanks composed of circumferential surfaces adjacent to the polygonal surface, and cutting edges defining a ridge line where the rake faces and flanks intersect each other as cutting edges. The rake faces have serrations where mount portions and valley portions are arrayed alternately to intersect the cutting edges. The ridge line has a waveform shape when the flanks are viewed from above. Bottom portions and top portions of the waveform are formed into concave circular arc portions and convex circular arc portions, respectively, and are alternately repeated. Both of the concave and convex circular arc portions are a ¼ circular arc or more to a ⅓ circular arc or less. Each of the concave circular arc portions is unevenly located between the convex circular arc portions adjacent thereto.

主权项

1. A milling insert, comprising:
an insert body having a polygonal tabular shape, the insert body comprising:
rake faces provided on one polygonal surface of the insert body;flanks composed of circumferential surfaces adjacent to the polygonal surface; andcutting edges defining a ridge line where the rake faces and the flanks intersect each other, wherein, the rake faces include serrations having pluralities of mount portions and valley portions that are arrayed alternately to intersect the cutting edges, wherein, when the flanks are viewed along an axis transverse to a longitudinal axis of the insert body, the ridge line has a waveform shape in which bottom portions and top portions are formed into concave circular arc portions and convex circular arc portions, respectively, and are alternately repeated, wherein, both of the concave circular arc portions and the convex circular arc portions are a ¼ circular arc or more to a ⅓ circular arc or less, wherein, each concave circular arc portion that is located between two adjacent convex circular arc portions is positioned so as to be closer to one of the two adjacent convex circular arc portions and farther from the other of the two adjacent convex circular arc portions, and wherein the ridge line is formed with a pitch that narrows as the ridge line extends in a direction corresponding with an arc sequence of: farther-spaced convex circular arc portion, concave circular arc portion, closer-spaced convex circular arc portion, and the pitch gradually narrows over at least three iterances of the arc portion sequence.