Cutting insert and tool for machining a workpiece

A tool for machining a workpiece, in particular for tangential milling, having a tool holder which has at least one cutting-insert receptacle in which a cutting insert is releasably fastened, the cutting insert comprising:

• two identical parts, wherein each part has a base surface, two identical mutually opposite main sides and two identical mutually opposite secondary sides, and wherein the base surface of the one of the two parts is opposite and parallel to the base surface of the other one of the two parts;
• four rectilinear main cutting edges, wherein each of the two parts comprises two of the four rectilinear main cutting edges;
• four first segmental cutting edges, wherein each of the two parts comprises two of the four first segmental cutting edges;
• four second segmental cutting edges, wherein each of the two parts comprises two of the four second segmental cutting edges;
• a through-bore having a bore axis which extends perpendicularly and centrally through the two base surfaces
• wherein the cutting insert has a 180° rotational symmetry about the bore axis, wherein the two identical parts are connected to each other along a center plane which extends orthogonally to the bore axis and has the same distance from each of the two base surfaces,
• wherein the four main cutting edges extend parallel to the center plane, wherein each main side comprises one of the four main cutting edges, wherein the two main cutting edges of each part extend parallel to one another and transversely to the two main cutting edges of the respective other part, and wherein each main cutting edge transitions at its respective first end into one of the four first segmental cutting edges and at its respective second end, opposite the first end, into one of the four second segmental cutting edges, wherein each secondary side comprises (i) a planar bearing surface which extends orthogonally to the center plane, (ii) a first protrusion and (iii) a second protrusion, wherein the first and the second protrusions each project with respect to the bearing surface arranged on the respective same secondary side, wherein each of the first segmental cutting edges is arranged on one of the first protrusions and each of the second segmental cutting edges is arranged on one of the second protrusions, and wherein the bearing surfaces of each part extend parallel to the main cutting edges of the respective other part.

A cutting insert for a tool for machining a workpiece, wherein the cutting insert has a 180° rotational symmetry about a bore axis extending perpendicularly and centrally through two opposing, identical base surfaces of the cutting insert, and has two identical parts which are connected along a center plane, wherein said center plane extends orthogonally to the bore axis and has the same distance from each of the two base surfaces, wherein each part has two identical mutually opposite main sides and two identical mutually opposite secondary sides, wherein each main side has a rectilinear main cutting edge extending parallel to the center plane, and each secondary side has a planar bearing surface extending orthogonally to the center plane, wherein the two main cutting edges of each part extend parallel to one another and transversely to the two main cutting edges of the respective other part, and wherein the two main cutting edges of each part extend parallel to the two bearing surfaces of the respective other part, wherein each main cutting edge transitions at its respective first end into a first segmental cutting edge which is arranged on a first protrusion provided on an adjacent secondary side of the respective part, and wherein each main cutting edge transitions into a second segmental cutting edge at its respective second end, opposite the first end, which is arranged on a second protrusion provided on the respective other adjacent secondary side of the respective part, wherein the first and the second protrusions each project with respect to the bearing surface arranged on the respective same secondary side.