A substantially parallelogramatic insert having a downward inclined main cutting edge and an auxiliary cutting edge in part of a long-side ridgeline and a short-side ridgeline adjacent to a pair of corner cutting edges of an upper surface; the main cutting edge being constituted by first to third straight cutting edges; the first to third straight cutting edges being connected in a bent-line shape with inward obtuse crossing angles when viewed from above, such that the second straight cutting edge is positioned outermost; and cutting edge angles .sub.1, .sub.2, .sub.3 between the rake faces and flanks of the first to third straight cutting edges meeting the relation of .sub.1>.sub.2>.sub.3.

A cutting insert for a rotary cutting tool has a second surface that includes a second seating surface having a shape of a flat surface. The first cutting edge has a first main cutting edge portion and a first sub cutting edge portion. The second cutting edge has a second main cutting edge portion and a second sub cutting edge portion. When viewed in a direction from the first surface toward the second surface, at least a portion of the second sub cutting edge portion is located outside the first main cutting edge portion, and at least a portion of the first sub cutting edge portion is located outside the second main cutting edge portion. When viewed in the direction from the first surface toward the second surface, each of the first sub cutting edge portion and the second sub cutting edge portion has a shape of a curved line.

In the cutting insert of the present invention, the cutting edge portion includes: a first corner edge; a major cutting edge continuous with a first end portion (S1) of the first corner edge near the short-side-direction side surface and formed into a straight line; a first minor cutting edge continuous with a second end portion (S2) of the major cutting edge and formed into a circular arc; and a second minor cutting edge continuous with a third end portion (S3) of the first minor cutting edge and 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.

The technical objective of the present invention is to provide a double-sided cutting insert having a high feed rate, which can increase the edge strength and reduce the cutting load, and thus can be suitable for high feed rate processing. To this end, a double-sided cutting insert having a high feed rate according to the present invention comprises: two main surfaces that face in opposite directions; two shorter side surfaces, which connect between the two main surfaces, and which face in opposite directions; two longer side surfaces, which connect between the two main surfaces and between the two shorter side surfaces, which face in opposite directions, and the width of which is larger than that of the shorter side surfaces; and a fastening hole that extends through the two longer side surfaces such that a cutting tool fastening bolt is inserted therein, wherein the double-sided cutting insert having a high feed rate comprises a shorter cutting edge provided on a boundary portion between each of the main surfaces and each of the shorter side surfaces, a longer cutting edge provided on a boundary portion between each of the main surfaces and each of the longer side surfaces, and a corner cutting edge that connects between the shorter cutting edge and the longer cutting edge, and the shorter cutting edge has a curved shape that is outwardly convex, when the same is viewed from a direction of the main surfaces.

A double-sided, indexable, non-positive ramping insert has a 180-degree rotational symmetry about each of the first, second and third axes of a three-dimensional Euclidean space. The ramping insert includes two first surfaces and an insert peripheral surface which extends therebetween. The ramping insert includes four cutting portions, each includes a major cutting edge, a wiper edge connected transversely thereto via a corner cutting edge and a ramping edge which extends transversely from the wiper edge in a view parallel to the first axis. Each peripheral surface includes four non-positive ramping relief surfaces, each of which extends from a respective ramping edge towards, and not beyond, a first median plane which is defined by the second and third axes.

A double-sided, indexable, non-positive ramping insert has a 180-degree rotational symmetry about each of the first, second and third axes of a three-dimensional Euclidean space. The ramping insert includes two first surfaces and an insert peripheral surface which extends therebetween. The ramping insert includes four cutting portions, each includes a major cutting edge, a wiper edge connected transversely thereto via a corner cutting edge and a ramping edge which extends transversely from the wiper edge in a view parallel to the first axis. Each peripheral surface includes four non-positive ramping relief surfaces, each of which extends from a respective ramping edge towards, and not beyond, a first median plane which is defined by the second and third axes.

A technical object is to provide an insert capable of preventing escaping of the insert from an assembly of the insert and a tool holder. To this purpose, the insert includes an insert body, and a holder fastening portion provided in the insert body to be fastened to the tool holder, in which the holder fastening portion includes one or more fastening holes formed through the insert body from an upper surface to a lower surface, and one or more locking recesses formed by being recessed in a lower surface periphery of the insert body.

A cutting insert and a cutting tool having same are provided. The cutting insert includes an upper surface, a lower surface having a flat surface, side surfaces connecting to each of the upper surface and the lower surface, and cutting edges being formed by the upper surface and the side surfaces. A first cutting edge among the cutting edges is inclined downward. A major side surface among the side surfaces comprises a first major side surface connected to the upper surface so as to constitute the first cutting edge, and a second major side surface connected to the first major side surface and the lower surface. The first major side surface has a reversely positive surface, and the second major side surface has a reversely positive surface or a negative surface, and a minor side surface among the side surfaces has a positive surface or a negative surface.

A double-sided, indexable cutting insert for a milling cutter includes a first surface, a second surface, and side surfaces. Cutting edges are defined at an intersection between the first and second surfaces and side surfaces. Each cutting edge includes a first cutting-edge portion, a second cutting-edge portion and a third cutting-edge portion. The first and second surfaces include diagonally opposite recessed regions. The cutting insert is mounted in a milling cutter defining a radial rake angle, A, and a ramping angle, B, with respect to a central, rotational axis of the milling cutter that provide superior performance for both milling and ramping cutting operations.

A cutting insert and a gear milling cutter is disclosed. A first major side portion of an insert body of the cutting insert is provided with a first recess having a first bottom surface (24a) and a second major side portion is provided with a second recess having a second bottom surface. The first and second bottom surfaces extend substantially in parallel with a longitudinal axis of the insert body. A first minor side portion is provided with a third recess having a third bottom surface and a second minor side portion is provided with a fourth recess having a fourth bottom surface, the third and fourth bottom surfaces extending across the longitudinal axis. Thus, the cutting insert may be supported in a relevant gear milling cutter against one of the first and second bottom surfaces and against one of the third or fourth bottom surfaces.