Abstract: What is presented is a cutting insert including a polygonal plate-shaped insert main body that includes: two polygonal surfaces; a side surface; and a cutting edge, the insert main body has a mounting hole that is centered on an insert center line passing through centers of the two polygonal surfaces, the cutting edge includes a major cutting edge extending from a first end of a corner edge located at a corner of the polygonal surface, and, in the opening of the mounting hole, a plurality of protrusions protruding with respect to a boss surface around an opening of the mounting hole are formed at intervals in a peripheral direction in an inner periphery side region of the major cutting edge.

Abstract: A cutting insert includes a polygonal plate-shaped insert main body having two polygonal surfaces, a side surface having a flank, and a cutting edge to be formed in an intersection ridgeline portion between a rake face and the flank. The insert main body has a rotationally symmetrical shape with respect to an insert center line, and has a front-rear reversely symmetrical shape with respect to the polygonal surface. The cutting edge includes a corner cutting edge, a major cutting edge extending from an one end of the corner cutting edge, and a wiper cutting edge extending from an one end of the major cutting edge in a direction intersecting the major cutting edge at an obtuse angle. A first region is disposed where a clearance angle of the flank gradually decreases to a negative angle after continuously passing through 0° from a positive angle.

Abstract: A cutting insert includes a main surface formed in a substantially parallelogram shape and having a pair of acute angle corner portions and a pair of obtuse angle corner portions, a seating surface that faces a side opposite to the main surface, a side surface that connects the main surface and the seating surface to each other, a corner cutting edge disposed in the acute angle corner portion, and a main cutting edge and a subsidiary cutting edge which are respectively disposed in a pair of side ridge portions of the main surface located each other across the acute angle corner portion. A mounting hole into which the fixing member is inserted penetrates the main surface and the seating surface. The main cutting edge is inclined at an inclination angle equal to or larger than 8° with reference to a plane perpendicular to an axial direction of the mounting hole.

Abstract: A cutting insert includes a cutting edge portion, and the cutting edge portion includes a bottom cutting edge forming an arc shape that protrudes toward a front end side in a central axis direction, an outer peripheral cutting edge forming an arc shape that protrudes toward an outside in a radial direction, and a cutting edge of corner that connects an outer end of the bottom cutting edge in the radial direction and a front end of the outer peripheral cutting edge in the central axis direction and forms an arc shape that protrudes toward a front end outer circumferential side. The bottom cutting edge and the outer peripheral cutting edge are formed so as to form a linearly symmetric shape together with respect to an imaginary straight line that passes through an arc central point of the cutting edge of corner and intersects the central axis.

Abstract: What is presented is a cutting insert including a polygonal plate-shaped insert main body that includes: two polygonal surfaces; a side surface; and a cutting edge, the insert main body has a mounting hole that is centered on an insert center line passing through centers of the two polygonal surfaces, the cutting edge includes a major cutting edge extending from a first end of a corner edge located at a corner of the polygonal surface, and, in the opening of the mounting hole, a plurality of protrusions protruding with respect to a boss surface around an opening of the mounting hole are formed at intervals in a peripheral direction in an inner periphery side region of the major cutting edge.

Abstract: A cutting insert includes a polygonal plate-shaped insert main body having two polygonal surfaces, a side surface having a flank, and a cutting edge to be formed in an intersection ridgeline portion between a rake face and the flank. The insert main body has a rotationally symmetrical shape with respect to an insert center line, and has a front-rear reversely symmetrical shape with respect to the polygonal surface. The cutting edge includes a corner cutting edge, a major cutting edge extending from an one end of the corner cutting edge, and a wiper cutting edge extending from an one end of the major cutting edge in a direction intersecting the major cutting edge at an obtuse angle. A first region is disposed where a clearance angle of the flank gradually decreases to a negative angle after continuously passing through 0° from a positive angle.

Abstract: A cutting insert includes a main surface formed in a substantially parallelogram shape and having a pair of acute angle corner portions and a pair of obtuse angle corner portions, a seating surface that faces a side opposite to the main surface, a side surface that connects the main surface and the seating surface to each other, a corner cutting edge disposed in the acute angle corner portion, and a main cutting edge and a subsidiary cutting edge which are respectively disposed in a pair of side ridge portions of the main surface located each other across the acute angle corner portion. A mounting hole into which the fixing member is inserted penetrates the main surface and the seating surface. The main cutting edge is inclined at an inclination angle equal to or larger than 8° with reference to a plane perpendicular to an axial direction of the mounting hole.

Abstract: A cutting insert includes a cutting edge portion, and the cutting edge portion includes a bottom cutting edge forming an arc shape that protrudes toward a front end side in a central axis direction, an outer peripheral cutting edge forming an arc shape that protrudes toward an outside in a radial direction, and a cutting edge of corner that connects an outer end of the bottom cutting edge in the radial direction and a front end of the outer peripheral cutting edge in the central axis direction and forms an arc shape that protrudes toward a front end outer circumferential side. The bottom cutting edge and the outer peripheral cutting edge are formed so as to form a linearly symmetric shape together with respect to an imaginary straight line that passes through an arc central point of the cutting edge of corner and intersects the central axis.

Abstract: 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 ?1, ?2, ?3 between the rake faces and flanks of the first to third straight cutting edges meeting the relation of ?1>?2>?3.

Abstract: 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 ?1, ?2, ?3 between the rake faces and flanks of the first to third straight cutting edges meeting the relation of ?1>?2>?3.