Cutting insert, cutting tool, and method of manufacturing machined product using them

摘要

In a cutting insert according to an embodiment of the present invention, an upper surface includes: a first concave groove which is continuous with a first cutting edge and extends along a longitudinal direction; a pair of second concave grooves which are respectively continuous with a pair of second cutting edges and extend along the longitudinal direction; and a pair of protruded parts respectively located between the first concave groove and the pair of second concave grooves. The pair of protruded parts are respectively continuous with an end surface cutting edge and are separated from each other by a larger distance therebetween as separating from the end surface cutting edge. A cutting tool with the cutting insert, and a method of manufacturing a machined product by using the cutting tool are also provided.

主权项

1. A cutting insert, comprising:
an upper surface that lies in a plane formed by an X axis and a Y axis, wherein the X axis and the Y axis are orthogonal and also orthogonal to a Z axis; a lower surface that lies in a plane formed by the X axis and the Y axis and is separated by a distance along the Z axis from the upper surface; a pair of side surfaces, a left side surface and a right side surface, that lie in a plane formed by the Z axis and the Y axis and are separated by a distance along the X axis and connect the upper and lower surfaces; a front end surface that lies in a plane formed by the X axis and the Z axis and connects the upper and lower surfaces; a rear end surface that lies in the plane formed by the X axis and the Z axis that is a distance along the Y axis from the front end surface and connects the upper and lower surfaces, wherein; the upper, lower, sides, front end, and rear end surfaces form a solid shape; a first cutting part is located along the front end surface at an intersection of the front end surface and the upper surface, wherein the cutting part is divided into a first cutting edge located in the middle of a pair of second cutting edges, wherein; the first cutting edge is concave towards a midpoint of the cutting part, wherein; the upper surface includes a first concave groove which is connected to the first cutting edge and extends towards the rear end surface along the Y axis, a pair of second concave grooves which are respectively connected to the pair of second cutting edges and extend towards the rear end surface along the Y axis, and a pair of protruded parts located between the first concave groove and the pair of second concave grooves respectively, a pair of second cutting parts located along the pair of side surfaces at the intersection of the pair of side surfaces and the upper surface, the pair of protruded parts are respectively continuous with the first cutting part and separated from each other by a larger distance therebetween as separating from the first cutting part, a top portion of each of the pair of protruded parts is inclined so as to slant downwards towards the lower surface as extending towards the rear end surface from the first cutting part in a side view; and each of the pair of second cutting parts is inclined so as to slant downwards towards the lower surface as extending towards the rear end surface from the first cutting part in a side view, and there is a relationship of α1<β1<γ1, where α1 is an angle formed by a top portion of at least one of the pair of protruded parts and a reference plane perpendicular to a central axis extending between the upper surface and the lower surface, β1 is an angle formed by at least one of the pair of second cutting parts and the reference plane, and γ1 is an angle formed by the first concave groove and the reference plane in a side view or a sectional view parallel to a longitudinal direction.