The invention relates to an apparatus for processing cylinder walls of internal combustion engines (1), including a cutting element (4). The cutting element (4) is arranged on a rotary cutting ring (3). The cutting element (4) has a slit contour (5) with a plurality of cutting edges (6) arranged next to each other in a direction of an axis of rotation of the rotary cutting ring. And, the individual cutting edges (6) face in a direction of rotation of the rotary cutting ring.

The technical objective of the present invention is to provide a cutting insert that has an improved fastening property with a cutting tool, thereby preventing reduction of the service life. To this end, the cutting insert according to the present invention has three corners along the circumference thereof; an upper main cutting edge, which is formed on the edge between the upper surface and the first side surface, and an upper sub cutting edge, which is formed on the edge between the upper surface and the second side surface, are continuously disposed between respective corners; the lower surface has the same shape as that of the upper surface; and the angle defined between the upper main cutting edge and the upper sub cutting edge, which are placed on both sides with reference to each corner, is larger than or equal to 85? and is smaller than 90?.

A cutting insert according to an embodiment of the present invention has an upper surface, a lower surface, a side surface connected to each of the upper surface and the lower surface, and a cutting edge located along an intersection of the upper surface and the side surface. The upper surface has a land surface disposed along the cutting edge, a rake surface which is located further inside than the land surface and is inclined so as to have a smaller height as departing from the land surface, and a bottom surface located further inside than the rake surface. The rake surface has a projection-shaped first region and a concave-shaped second region which are alternately disposed along the bottom surface. The first region has a first recess that reaches the second region adjacent to the first region.

A double-sided tangential cutting insert includes two identical opposing end surfaces and a peripheral side surface extending between the end surfaces. The peripheral side surface has two opposing identical major side surfaces, two opposing identical minor side surfaces and four corner surfaces. Each of the end surfaces include two spaced major cutting edges formed at an intersection between the end surface and one of the major side surfaces, two spaced minor cutting edges formed at an intersection between the end surface and one of the minor side surfaces, two diagonally opposite raised corners, each with a corner cutting edge, two diagonally opposite lowered corners, each having a corner non-cutting edge, major rake surfaces adjacent the major cutting edges, minor rake surfaces adjacent the minor cutting edges, cutting corner rake surfaces adjacent the corner cutting edges, and non-cutting corner rake surfaces adjacent the non-cutting edges.

The purpose of the present invention is to provide a cutting insert which can minimize friction with a chip and maximize heat-radiating performance. To this end, the present invention provides a cutting insert comprising: an upper surface; a lower surface; a plurality of lateral surfaces for connecting the upper surface with the lower surface; a main cutting edge formed between the lateral surface and the upper surface; and a main cutting edge land and a main cutting edge incline formed in series between the main cutting edge and the upper surface, wherein the main cutting edge incline has a first wavy shape in which two or more incline convex parts and two or more incline concave parts are repeated from the main cutting edge land toward the upper surface.

A milling insert, including an upperside, an underside, and a reference plane parallel to the upperside and the underside. A plurality of indexable cutting edges are formed along a peripheral borderline in transitions between at least the upperside and a number of clearance surfaces. Each cutting edge includes a chip-removing main edge and a surface-wiping secondary edge, the secondary edge forming an obtuse angle with the main edge as viewed in planar view from the upperside. The main edge, from a first end of the main edge adjacent to the secondary edge, first declines toward the underside of the milling insert and then, from a lowest part, rises toward an opposite second end of the main edge. The secondary edge is inclined at an angle () in relation to the reference plane as viewed perpendicularly to the clearance surface of the secondary edge, such that a first end of the secondary edge connected to the main edge is situated on a lower level than the opposite, second end of the secondary edge.

A milling insert, including an upperside, an underside, and a reference plane parallel thereto. A plurality of indexable cutting edges are formed along a peripheral borderline in transitions between at least the upperside and a number of clearance surfaces. Each cutting edge includes a chip-removing main edge and a surface-wiping secondary edge. The main edge, from a first end of the main edge adjacent to the secondary edge, declines toward the underside of the milling insert and then, from a lowest part, rises toward an opposite second end of the main edge. The secondary edge is inclined at an angle () in relation to the reference plane as viewed perpendicularly to the clearance surface of the secondary edge, such that a first end of the secondary edge connected to the main edge is situated on a lower level than the opposite, second end of the secondary edge.