Cutting insert, rotary tool, and method for manufacturing machined product
An insert includes a cutting portion and a shaft portion. The cutting portion includes: a cutting edge that is located on a side of a first end; an end surface that is located on a side of the side of a second end; and a first through hole extending from the end surface toward the first end. The first through hole includes: a first opening that is located on the side of the first end; and a second opening located on the side of the second end. The first opening is positioned in the rear of the second opening in a rotational direction of the rotational axis.
1 . A cutting insert, comprising:
a cutting portion that is located on a side of a first end of the cutting insert; and
a shaft portion that is located on a side of a second end of the cutting insert, wherein
the cutting insert extends from the first end to the second end along a rotational axis, and
the cutting portion comprises
a cutting edge that is located on the side of the first end,
an end surface located on a side of the shaft portion, and
a first through hole extending from the end surface toward the first end,
the shaft portion extends from the end surface to the second end,
the first through hole comprises
a first opening that is located on the side of the first end, and
a second opening that is located on the side of the shaft portion, and
the first opening is positioned in a rear of the second opening in a rotational direction of the rotational axis.
2 . The cutting insert according to claim 1 , wherein the shaft portion comprises a first groove extending from the first through hole toward the second end.
3 . The cutting insert according to claim 1 , wherein
the cutting edge comprises
a chisel edge extending from the rotational axis toward an outer circumference,
a thinning edge extending from the chisel edge toward the outer circumference, and
a main cutting edge extending from the thinning edge toward the outer circumference,
the cutting portion further comprises a thinning surface extending from the thinning edge toward the second end, and
the first opening is positioned on the thinning surface.
4 . The cutting insert according to claim 3 , wherein
the cutting portion further comprises a flute extending from the main cutting edge toward the second end, and
the second opening is positioned away from the flute.
5 . The cutting insert according to claim 1 , wherein the first opening is positioned farther from the rotational axis than the second opening is in a front view from the side of the first end.
6 . The cutting insert according to claim 1 , wherein the rotational direction of the rotational axis is a counterclockwise direction in a front view of the cutting insert from the side of the first end.
7 . The cutting insert according to claim 6 , wherein
the cutting insert comprises a further first through hole,
the first through hole and the further first through hole are rotationally symmetrical with respect to the rotational axis,
the further first through hole has a further first opening located on the side of the first end and a further second opening located on the side of the shaft portion, and
the first opening of the first through hole at least partially overlaps the further second opening of the further first through hole in the front view of the cutting insert from the side of the first end.
8 . A rotary tool, comprising:
a cutting insert; and
a holder, wherein
the cutting insert includes:
a cutting portion that is located on a side of a first end of the cutting insert; and
a shaft portion that is located on a side of a second end of the cutting insert,
the cutting insert extends from the first end to the second end along a rotational axis,
the cutting portion includes:
a cutting edge that is located on the side of the first end,
an end surface located on a side of the shaft portion, and
a first through hole extending from the end surface toward the first end,
the shaft portion extends from the end surface to the second end,
the first through hole includes:
a first opening that is located on the side of the first end, and
a second opening that is located on the side of the shaft portion,
the first opening is positioned in a rear of the second opening in a rotational direction of the rotational axis,
the holder includes:
a shank having a rod shape extending along the rotational axis, and
a body extending along the rotational axis,
the body includes a pocket that opens at a leading end of the body, and
the cutting insert is configured to be attached to the pocket.
9 . The rotary tool according to claim 8 , wherein
the holder comprises
a second through hole extending along the rotational axis in the shank and the body, and
a second groove recessed from an inner circumference surface of the pocket in a direction away from the rotational axis, the second groove being connected to the first through hole of the cutting insert and the second through hole of the holder.
10 . The rotary tool according to claim 9 , wherein
the shaft portion comprises a first groove extending from the first through hole toward the second end, and
the second groove faces the first groove.
11 . A method of manufacturing a machined product, the method comprising:
rotating the rotary tool according to claim 10 ;
bringing the rotary tool into contact with a workpiece; and
separating the rotary tool from the workpiece.
12 . The rotary tool according to claim 9 , wherein
the shaft portion of the cutting insert includes a flow path surface extending in a direction toward the second end from the second opening.
13 . The rotary tool according to claim 12 , wherein
the flow path surface of the cutting insert and the second groove of the holder are configured to form a gap flow path between the pocket and the shaft portion.
14 . A rotary tool, comprising:
a holder; and
a cutting insert extending from a first end to a second end along a rotational axis, wherein
the holder comprises
a shank having a rod shape extending along the rotational axis, and
a body extending along the rotational axis,
the body comprises a first end surface at a leading end of the body, wherein a pocket is opening on the first end surface,
the cutting insert is configured to be attached to the pocket,
the cutting insert comprises
a cutting portion that is located on a side of the first end of the cutting insert, and
a shaft portion that is located on a side of the second end of the cutting insert,
the cutting portion comprises
a cutting edge that is located on the side of the first end,
a second end surface configured to be in contact with the first end surface of the body, and
a first through hole extending from the second end surface toward the first end,
the shaft portion extends from the first end surface to the second end,
the first through hole comprises
a first opening that is located on the side of the first end, and
a second opening that is located on the side of the shaft portion, and
the first opening is positioned in a rear of the second opening in a rotational direction of the rotational axis.