Mitsubishi Materials Corporation

Hisashi Daiguji

Yoshihiko Kimura

A tool main cutting edge extends rearward in a rotating direction as it approaches a rear end at the outer periphery. The main cutting edge is a convexly curved line protruding toward the outside of a rake face viewed from the top and another convexly curved line extending toward the seat face, convexly curving from one end of the main cutting edge to the other, viewed from the side. When mounted, an inclination angle defined by the rake face gradually decreases from one end toward the other, and a projection line of a rotation about a rotation axis of the tool forms a convex arc smoothly coming, at a middle portion of the main cutting edge, into contact with a cylindrical surface about the axis and gradually retreats inward from the cylindrical surface as it approaches both ends of the main cutting edge.

Throwaway insert and throwaway-type rotary cutting tool

A throwaway insert and a cutting tool enable a high speed cutting operation for a metallic material having great ductility such as aluminum and obtaining a vertical wall with a high quality machined surface while improving chip control. The throwaway insert comprises a major cutting edge including a tapered cutting edge connected to a cutting edge of a nose portion, and a curved cutting edge connected to an end of the tapered cutting edge at a connection point. The curved cutting edge is formed so as to extend along an imaginary cylindrical surface whose center axis coincides with the axis of rotation of a tool main body, and tapered cutting edge is formed so as to gradually curve from the imaginary cylindrical surface toward the inside of the imaginary cylindrical surface as the distance from the curved cutting edge increases, and the distance from the nose portion decreases. The throwaway insert is attached to the tool main body in which the surface of the distal end thereof is machined so that surface roughness thereof is less than 3.2 &#x3bc;m when indicated by the Ry roughness.

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Ibaraki, Japan

Hisashi Daiguji