JP2020192611A5 - - Google Patents

Claims (9)

A plurality of outer peripheral blades formed spirally on the outer peripheral surface on the tip side of the tool body that can rotate around the central axis at predetermined intervals, a chip discharge groove formed on the front side in the rotation direction of the outer peripheral blade, and the above. A cutting tool having a plurality of bottom blades formed on the tip surface of the tool body and continuous with the outer peripheral blade.
The chip discharge groove having the outer peripheral rake face of the outer peripheral blade is
A first flute groove extending from the front end surface to the rear end side,
A second flute groove formed by cutting off a region on the distal end side of the first flute groove, having a length shorter than that of the first flute groove, and having a trailing end connected to the first flute groove.
A cutting tool characterized in that the second flute groove is formed in the circumferential direction from the outer peripheral rake face side of the first flute groove to the outer peripheral relief surface. The radius length connecting the central axis and the outer peripheral blade in a cross-sectional view orthogonal to the central axis of the tool body is set to D / 2.
At an angle of 20 ° toward the outer peripheral flank surface of the outer peripheral blade having the second flute groove, the outer peripheral surface has a wall thickness of 88% to 97% of the radius length D / 2 in length from the central axis. Have,
Claim that the outer peripheral surface has a wall thickness of 78% to 93% of the radius length D / 2 in a length from the central axis at an angle of 30 ° toward the outer peripheral flank surface of the outer peripheral blade. The cutting tool described in 1. In a cross section orthogonal to the central axis in the vicinity of the tip surface of the tool body, an intersecting protrusion is formed on the outer peripheral rake face of the outer peripheral blade so as to project at the boundary between the first flute groove and the second flute groove. The cutting tool according to claim 1 or 2. The intersecting protrusion protrudes by 5 ° or less with respect to the virtual line connecting the central axis and the outer peripheral blade, and is formed at a position of 65% or more of the radius length D / 2 from the central axis to the outer peripheral blade. The cutting tool according to claim 3. The radius length connecting the central axis and the outer peripheral blade is set to D / 2.
The first core thickness in the region of the second flute groove is set in the range of 0.55D to 0.70D.
Claim 1 that the second core thickness in the region of the first flute groove behind the second flute groove is set in the range of 0.60D to 0.80D and is 0.05D or more larger than the first core thickness. The cutting tool according to any one of 4 to 4. The cutting tool according to any one of claims 1 to 5, wherein the length of the second flute groove is set in the range of 0.5D to 1.5D from the tip surface. The cutting tool according to any one of claims 1 to 6, wherein the width of the outer peripheral flank surface on the tip side in the circumferential direction is set in the range of 0.05D to 0.25D. The cutting tool according to any one of claims 1 to 7, wherein the plurality of bottom blades are unequally divided and the plurality of outer peripheral blades are set to unequal leads. The cutting tool according to any one of claims 1 to 8, wherein the rake angle of the outer peripheral blade exceeds 0 °.