In a cutting tool rotatable about a tool axis, a reversible cutting insert is removably secured in a tool body. The cutting insert has opposing top and bottom end surfaces interconnected by a peripheral surface, and a median plane located therebetween. The peripheral surface includes four side surfaces alternating with four corner surfaces, the side and corner surfaces intersecting the top surface to form top major cutting edges and top corner cutting edges, respectively. Each side surface has a median surface and a top major relief surface. Each top major relief surface forms an acute internal top major relief angle with the median plane, and the median plane intersects the four median surfaces to define an imaginary median square. In a top end view of the cutting insert, the four top major cutting edges define an imaginary top major square rotationally offset from the imaginary median square.

A method for milling a workpiece by way of at least one substantially polygonal cutting insert, which is arranged in a tool holder. A spindle axis of the tool holder encloses an angle of more than 0° with a plane normal to a machined workpiece surface. An effective lead angle between a main cutting edge of the cutting insert and the machined workpiece surface lies between 0° and 20°.

A cutting insert of the present invention comprises: an upper surface and a lower surface; first and second lateral surfaces; first and second cutting edge parts; and corner cutting edges, wherein the first cutting edge part includes: a first main cutting edge for forming one end at a portion spaced farthest away from the corner cutting edge; a first sub-cutting edge connected to the corner cutting edge; and a first auxiliary cutting edge for connecting the first main cutting edge and the first sub-cutting edge so as to form a step between the same, and the first sub-cutting edge and the corner cutting edge form one straight line when viewed toward the first lateral surface, and are inclined upward in the direction opposite to the direction toward the lower surface while gradually going in the direction toward the second cutting edge part.

A reversible cutting insert for milling has first and second cutting edges formed at the transitions from the top and bottom surfaces to a lateral face. The cutting insert has a 4-fold rotational symmetry. A reference plane extends perpendicular to the axis of symmetry. The cutting edges have four cutting edge portions. One cutting edge portion is a main edge and a wiper edge that are connected by a rounded cutting corner. The first and second cutting edges are at the greatest distance from the reference plane in the region of the cutting corners. Main and wiper clearance faces directly adjoin an assigned main edge and wiper edge, respectively, in the circumferential lateral face. Exterior angles between the main clearance faces and the reference plane are greater than exterior angles between the wiper clearance faces and the reference plane.

A cutting insert includes an insert peripheral surface that includes at least one planar major insert side abutment surface and an insert lower surface that includes an anti-slip recess recessed therein. The anti-slip recess includes at least one elongated and straight anti-slip groove. Each major insert side abutment surface is oriented parallel to a groove longitudinal axis of a respective anti-slip groove. An insert holder includes a holder pocket. The holder pocket includes a pocket peripheral surface which includes planar major pocket side abutment surface and a pocket base surface having an elongated and straight anti-slip rib. When the cutting insert is releasably attached to the insert holder, to constitute a fastened position of a cutting tool, the anti-slip rib is located in the anti-slip groove that is oriented parallel to the major insert side abutment surface that abuts the major pocket side abutment surface.

In a cutting tool rotatable about a tool axis, a reversible cutting insert is removably secured in a tool body. The cutting insert has opposing top and bottom end surfaces interconnected by a peripheral surface, and a median plane located therebetween. The peripheral surface includes four side surfaces alternating with four corner surfaces, the side and corner surfaces intersecting the top surface to form top major cutting edges and top corner cutting edges, respectively. Each side surface has a median surface and a top major relief surface. Each top major relief surface forms an acute internal top major relief angle with the median plane, and the median plane intersects the four median surfaces to define an imaginary median square. In a top end view of the cutting insert, the four top major cutting edges define an imaginary top major square rotationally offset from the imaginary median square.

A cutting insert includes a substrate and a cutting-edge insert. The substrate has, in a thickness direction of the substrate, a bottom surface, and a top surface opposite to the bottom surface. The top surface has a polygonal shape composed of a plurality of sides in a plan view as seen along the thickness direction. The top surface is provided with a projection projecting to a side opposite to the bottom surface along the thickness direction. The projection has a through-hole passing through the substrate along the thickness direction. The projection has a side surface contiguous to the top surface. The side surface is composed of a curved line protruding to a side opposite to the through-hole in the plan view as seen along the thickness direction.

A polygonal cutting blade having a circular arc-shaped groove in a hole includes a blade body composed of an upper surface, a lower surface and a plurality of main side surfaces connecting the upper surface and the lower surface. The blade body has a central hole penetrating through the upper surface and the lower surface, and is centrally symmetrical about a central axis of the central hole. At least one set of positioning side surface comprised of adjacent two of the main side surfaces is provided. An inner surface of the central hole has at least one circular arc-shaped groove fitting with a fastening screw for fixing the cutting blade. The circular arc-shaped groove directly faces toward an intersection of the two main side surfaces of the set of positioning side surface. A groove central axis of the circular arc-shaped groove has an offset distance from the central axis.

A cutting insert for milling operations, such as, face milling, slot milling, plunge milling, and ramping operations. The cutting insert exhibits a combination of favorable cutting-edge strength, and unique cutting-edge geometry to allow milling operations at relatively high feed rates. The cutting insert includes at least four convex cutting edges. Certain embodiments of square cutting inserts will have four convex cutting edges connected by nose corner regions. Each convex cutting edge includes a first curved cutting-edge region having a radius greater than or equal to two times a radius of the largest circle that may be inscribed on the top surface. Each convex cutting edge also includes a second curved cutting-edge region adjacent the first curved cutting-edge region and having a radius less than or equal to the diameter of the inscribed circle. Each convex cutting edge may also include one or more straight cutting-edge regions.

A cutting insert has a substantially triangular or square basic shape with a top surface and a base surface that are connected together by lateral flanks. A cutting edge is formed at the transition between at least one flank and the top surface. The cutting edge extends between cutting corners, and the cutting edge has a portion that is convex in side view of a flank. The convex portion of the cutting edge is bounded on both sides by concavely curved portions.