Mitsubishi Hitachi Tool Engineering, Ltd.

Hitachi Tool Engineering, Ltd.

Yuuki Hayashi

Yoshiyuki Kobayashi

Yasuhiro Kiuchi

Fumihiko Inagaki

Takao Nakamigawa

Yoshimitsu Nagashima

In an indexable rotary cutting tool of the present invention, a cutting edge portion of an insert includes a peripheral cutting edge, a bottom cutting edge, a cutting edge of a corner R, and a chamfered surface, a radial rake angle (&#x3b4;) of the cutting edge of the corner R has a negative value in an entire edge length region of the cutting edge of the corner R, and the radial rake angle (&#x3b4;) becomes a minimum value at an intermediate portion located between a pair of boundary points (P, Q) in the cutting edge of the corner R.

Indexable rotary cutting tool and insert

An indexable rotary cutting tool and insert is capable of performing a high-accuracy cutting process with high efficiency. A twist angle of an outer peripheral cutting edge of the tool has a positive value, an axial rake angle of the cutting edge of a corner R of the tool at a boundary point between the cutting edge of the corner R and the outer peripheral cutting edge has a positive value, the axial rake angle of the cutting edge of the corner R at a reference point has a negative value, and the radial rake angle at least between the boundary point and the reference point in an entire edge length region of the cutting edge of the corner R has a negative value. The radial rake angle at the reference point is smaller than the radial rake angle at the boundary point.

A ball-end mill includes arcuate cutting edges each extending from a tip end to a peripherally outermost point along a S shape curve when viewed from the front side, spirally-shaped, peripheral cutting edges each smoothly connected to each arcuate cutting edge, and a convex rake face of each arcuate cutting edge protruding forward in a rotation direction. Each arcuate cutting edge has a radial rake angle satisfying &#x3b2;&#x3c;&#x3b1;&#x2266;&#x3b3;, where &#x3b1; is a radial rake angle at a radial angle of 5&#xb0;, &#x3b2; is a radial rake angle at a radial angle of 90&#xb0;, and &#x3b3; is a radial rake angle at a rotationally most projecting point of the arcuate cutting edge. The radial rake angle has the maximum value at a radial angle in a range of 12-40&#xb0; and continuously decreases in a range from the rotationally most projecting point to the peripherally outermost point.

Growing community of inventors

Narita, Japan

Yuuki Hayashi