Abstract: A cutting insert in a non-limiting aspect of the present disclosure may include an upper surface, a lower surface, a lateral surface and a cutting edge. The upper surface may include a first corner and a first side. The upper surface may further include a first protrusion and a second protrusion. The first protrusion may be extended toward the first corner. The second protrusion may be located between the first corner and the first protrusion. The first protrusion may include an inclined surface. The inclined surface may be located along the first side. The inclined surface may include a first surface and a second surface. The second surface may be located further away from the first corner than the first surface. The first surface and the second surface may be individually inclined upward as going away from the first side, and having a concave shape as a whole.

Abstract: A cutting insert according to one non-limiting example has a quadrangular prism shape extending from a front end toward a rear end along a central axis, and comprises a cutting portion, and a main body portion. The main body portion includes an upper surface including a first flute having a V-shape extending along the central axis, and a lower surface including a second flute having a V-shape extending along the central axis. A first flute has a first region positioned on the rear end side and a second region positioned on the front end side with respect to the first region. An opening angle of the first flute in the first region is smaller than an opening angle of the first flute in the second region. An opening angle of the second flute is constant in a direction along the central axis.

Abstract: A cutting insert according to one non-limiting example has a quadrangular prism shape extending from a front end toward a rear end along a central axis, and comprises a cutting portion, and a main body portion. The main body portion has an upper surface having a V-shaped flute extending along the central axis. An opening portion and a bottom portion of the flute each have a convex shape protruding upward in a direction along the central axis. A first flute has a first region positioned on the rear end side and a second region positioned on the front end side with respect to the first region. An opening angle of the first flute in the first region is smaller than an opening angle of the first flute in the second region.

Abstract: A cutting insert in a non-limiting aspect of the present disclosure may include an upper surface, a lower surface, a lateral surface and a cutting edge. The upper surface may include a first corner and a first side. The upper surface may further include a rake surface, a bottom surface and a raised surface. The bottom surface may include a first bottom surface and a second bottom surface. The first bottom surface may be located on a bisector of the first corner. The second bottom surface may be located inwardly of the first side. The first bottom surface may be an inclined surface located closer to the lower surface as going away from the first corner. The second bottom surface may be an inclined surface located further away from the lower surface as going away from the first side.

Abstract: A cutting insert in a non-limiting aspect of the present disclosure may include an upper surface, a lower surface, a lateral surface and a cutting edge. The upper surface may include a first corner and a first side. The upper surface may further include a first protrusion and a second protrusion. The first protrusion may be extended toward the first corner. The second protrusion may be located between the first corner and the first protrusion. The first protrusion may include an inclined surface. The inclined surface may be located along the first side. The inclined surface may include a first surface and a second surface. The second surface may be located further away from the first corner than the first surface. The first surface and the second surface may be individually inclined upward as going away from the first side, and having a concave shape as a whole.