A cutting insert based on a non-limiting aspect has a first member and a second member joined to the first member. The second member has an upper surface and a side surface adjacent to the upper surface. The upper surface includes a first side, a second side and a corner. The upper surface has a first convex portion extending toward the corner, and a second convex portion extending from the first convex portion toward the first side. The second convex portion has a first end portion and a second end portion located closer to the corner than the first end portion. A first length from the first end to the first side is less than a second length from the second end portion to the first side in a top view.

The present invention relates to a cutting insert applicable to machining tools and the tool bearing it. The insert (1) has a cutting edge (12) which can be completely sharp or can have a rounding between R=0.030 mm and 0.050 mm, with an angle of impact (123) between 68 and 90 in both cases, and a rounded chip breaker (13), both arranged in a layer of polycrystalline diamond (PCD) (11) at least 1 mm thick covering the entire cutting surface of the insert (1).

The tool includes a body (2) formed by a core (22) coupleable to the machining center, said core externally bearing a perimetral sleeve (21) housing the cutting inserts (1), with the layer of PCD (11) thereof being in direct contact with the sleeve (21).

The invention may include a hydraulic system (23) between the sleeve (21) and the core (22).

To provide a cutting insert that readily fragmentizes chips, and that has excellent durability.

At least a cutting part of a cutting insert is formed of a sintered compact. The sintered compact includes a chip breaker that is a recessed portion in which a partial region of a cutting part upper surface is depressed downward. The chip breaker includes a downward inclined surface, an upward inclined surface, a jutting portion that juts out along a first axial line that passes through a distant end of a cutting edge, and a stepped surface that adjoins the jutting portion in a Y axis direction orthogonal to the first axial line. An upper end of the jutting portion is formed at a height of an upper stage. The stepped surface is formed at a height of an intermediate stage at a part closest to the first axial line.

A cutting insert may include a first surface, a second surface, a third surface and a cutting edge. The first surface may include a corner, a first side, a first inclined surface located along the corner, a second inclined surface located further inside than the first inclined surface, a third inclined surface located along the first side, a fourth inclined surface located further inside the first surface than the third inclined surface, and a protruded part located further inside than the second inclined surface and the fourth inclined surface. An inclination angle of the protruded part may be smaller than an inclination angle of the second inclined surface in a cross section along a bisector of the corner. The inclination angle of the protruded part may be larger than a third inclination angle in a cross section orthogonal to the first side.

There is provided a cutting insert having a low possibility that chips roughen a machined surface of a workpiece in back turning. The cutting insert includes a rake surface, a peripheral side surface, a front cutting edge which is provided on a ridge of the rake surface and the peripheral side surface, and a main cutting edge which is provided on the ridge so as to be continuous with the front cutting edge and has an extension direction which forms an obtuse angle with an extension direction of the front cutting edge, the main cutting edge is curved into a U shape over an entire length of an effective edge range which functions as a cutting blade, and the deepest point of the U shape is positioned in a range closer to a side of a corner than a position which divides a straight line connecting both ends of the main cutting edge at a ratio of 2:1 from the side of the corner positioned adjacent to the front cutting edge.

The present disclosure relates to a cutting insert. The cutting insert according to the exemplary embodiment of the present disclosure has a dot formed between a main cutting edge and a chip breaker, and the dot has a bridge formed between the main cutting edges. Therefore, a chip, which is produced during a cutting process, may come into contact with three points on a main cutting edge land portion, the bridge, and the dot. The chip may discharge heat generated from the cutting insert while the chip comes into contact with the three points.

A cutting tool having a cutting edge member which forms at least one corner part, wherein a material for the cutting edge member is selected from either diamond, an ultrahigh-pressure sintered body containing cubic boron nitride or a PVD or CVD coating applied to a surface of the ultrahigh-pressure sintered body. At least part of an intersecting edge between an end surface of the cutting edge member and a peripheral side surface thereof is provided with a cutting edge. A chip breaker comprising a breaker wall surface is formed in the end surface of the cutting edge member. The breaker wall surface has at least one projected surface part which bulges outwardly from the cutting tool. As viewed from the end surface, the recessed surface part is arranged so as to be apart from a virtual plane A which is defined so as to divide the corner part into halves.

In a cutting insert according to an embodiment of the present invention, an upper cutting edge includes, sequentially from a first corner to a second corner, a corner cutting edge, a minor cutting edge inclined as separating from the corner cutting edge at a first inclination angle on a basis of a vertical plane perpendicular to a central axis extending between upper and lower surfaces, and a major cutting edge inclined as separating from the minor cutting edge at a second inclination angle on the basis of the vertical plane so as to become more closer to the lower surface than the minor cutting edge. A cross section of a rake surface obtained by cutting an inwardly located end portion thereof along a direction of the central axis has a straight line shape or concave shape in a region crossing over at least a minor rake surface and a major rake surface. A cutting tool with the cutting insert, and a method of manufacturing a machined product by using the cutting tool are also provided.

According to the present disclosure, a cutting insert includes an upper surface having a polygonal shape and includes a corner, a side surface adjacent to the upper surface, a cutting edge and a protrusion. The cutting edge is located at a ridge part in which the upper surface intersects with the side surface and includes a corner part located at the corner. The protrusion is located on the upper surface. The protrusion includes a first protrusion on a bisector of the corner in a top view. The protrusion further includes a second protrusion adjacent to the first protrusion in a direction orthogonal to the bisector. The second protrusion is closer to the corner than the first protrusion in the top view.

A drill includes drill body and peripheral insert having a radial cutting edge extending generally in a direction of a radius of the drill body, and a central insert. The peripheral insert includes a rake face including a plurality of chipbreaker protrusions. A first angle measured between a line tangent to forward ends of the plurality of chipbreaker protrusions and the central axis of the drill body extending toward the shank end is an acute angle. Also a peripheral insert is disclosed.