Mitsubishi Hitachi Tool Engineering, Ltd.

Hitachi Tool Engineering, Ltd.

Tomohiro Murata

Hisanori Mura

Tadahiro Hibata

Fumihiko Inagaki

Masashi Noshita

A detachable cutting insert for an indexable rotary cutting tool, has a cutting edge portion that includes a major cutting edge continuous with a first end of a first corner edge near a short-side-direction side surface, which is formed into a straight line. The cutting insert has a first minor cutting edge that is continuous with a second end of the major cutting edge, which is formed into a circular arc. The cutting insert has a second minor cutting edge that is continuous with a third end of the first minor cutting edge, which is formed into a straight line. In a cross-sectional view of a rake face of the second minor cutting edge, perpendicular to the second minor cutting edge, a cross-sectional ridgeline of the rake face of the second minor cutting edge is formed into a convex shape protruding above a cross-sectional ridgeline of a reference plane.

Cutting insert and indexable rotary cutting tool

An insert detachably attached to an indexable rotary cutting tool, having an upper surface having cutting edges along the ridgeline, a lower surface, side surfaces, and a center hole for a fastening screw; each cutting edge having a corner cutting edge formed in each acute corner portion, and a bottom cutting edge and a peripheral cutting edge formed along the ridgelines on both sides of the corner cutting edge; the bottom cutting edge and the peripheral cutting edge having different clearance angles; a flank of the corner cutting edge having an angle-changing surface portion having a clearance angle continuously changing in a region from the bottom cutting edge to the peripheral cutting edge; and the length of the peripheral cutting edge being restricted by a receding portion adjacent to an upper end of the peripheral cutting edge.

Indexable rotary cutting tool and insert used therein

A negative cutting insert having a cutting edge comprising four long-side cutting edge portions for rough cutting and four short-side cutting edge portions for finish cutting, which are connected alternately, thereby being able to conduct rough cutting when attached to a rough-cutting tool body, and finish cutting when attached to a finish-cutting tool body. When such cutting inserts are used for rough or finish cutting and then reattached to a finish-cutting tool body or a rough-cutting tool body, finish or rough cutting can be conducted, thereby using all cutting edges thoroughly.

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Narita, Japan

Tomohiro Murata