Osg Corporation

Btt Corporation

Yasuo Hamatake

Jiro Osawa

Wataru Aoki

Tasuku Itoh

Katsutoshi Watanabe

Tamotsu Nagai

Hirotsugu Takahama

Masakazu Nakamura

In a semi-finishing cutter, rectangular tips and square tips are disposed in a staggered pattern in an axial direction in second to fourth step portions, so a single cutting edge is formed by a pair of one of the rectangular tips and one of the square tips. It is therefore possible to effectively reduce a frequency of contact with a blade root. A cutting speed of the semi-finishing cutter may be increased and a cutting feed may be made faster, so work in a semi-finishing process may be performed efficiently. The rectangular tips and the square tips have simple shapes, so known commercially available throwaway tips may be used. Accordingly, it is possible to provide the semi-finishing cutter in an easy-to-use form without increasing the cost.

Throwaway rotary cutting tool

In a rough cutting cutter, square tips and rectangular tips are disposed in a staggered pattern in an axial direction in second to fourth step portions, so a cutting edge is formed by a pair of one of the square tips and one of the rectangular tips. It is therefore possible to effectively reduce a frequency of contact with a blade root. Furthermore, in the second to a fifth step portions, ARs (rake angles in the axial direction) and RRs (rake angles in a radial direction) of the square tips and the rectangular tips gradually increase in order from a tip end to a back end of a tool body. It is therefore possible to suppress chatter vibration during machining and is possible to reduce roughness of a cut surface of a work material.

A neck portion grinding apparatus and method is designed to reduce working man-hours and to improve processing accuracy with respect to a processing of a workpiece. The neck portion grinding apparatus includes a grinding device having a disc-like grinding wheel and a wheel rotating device for rotating the grinding wheel, and a machine tool having a main shaft for rotatably supporting a rotating tool and a table mounting the grinding device thereon, and relatively moving the main shaft and the table by numeral control. A shape of a neck portion of the rotating tool can be changed by relatively moving the main shaft and the table while mutually rotating the rotating tool and the grinding wheel, and grinding the rotating tool by the grinding wheel.

Neck portion grinding apparatus and grinding device employed in the neck portion grinding apparatus

A ball endmill having (a) a cylindrical tool body and (b) ball-nosed end cutting edges each of which includes (b-1) a first portion, (b-2) a second portion and (b-3) a third portion. The first portion is defined by a circular arc which is convex in a direction of rotation of the tool body and which has a first radius of curvature as measured in a distal end view perpendicular to the axis. The second portion is defined by a straight line or a circular arc which is convex in the rotation direction and which has a second radius of curvature as measured in the distal end view. The third portion is defined by a circular arc which is convex in the rotation direction and which has a third radius of curvature as measured in the distal end view. The second radius of curvature is larger than the first radius of curvature. The third radius of curvature is smaller than the second radius of curvature.

Ball endmill

A ball endmill having a cylindrical tool body and ball-nosed end cutting edges each of which includes a first portion and a second portion continuous to the first portion. The first and second portions are located at a radially inner portion of each ball-nosed end cutting edge in a distal end view. The first portion is convex in a direction of rotation of the tool body and has a first radius of curvature seen in a distal end view. A ratio of the first radius of curvature to an outside diameter of the cylindrical body is between 0.025 and 0.10. The second portion is convex in the direction of the rotation of the tool body and has a second radius of curvature as measured in the distal end view. The second radius of curvature is larger than the first radius of curvature.

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Toyokawa, Japan

Yasuo Hamatake