Diamond-coated rotary cutting tool

Patent metadata

Field	Value
Publication number	US-11878353-B2
Application number	US-201816651488-A
Country	US
Kind code	B2
Filing date	Sep 28, 2018
Priority date	Sep 29, 2017
Publication date	Jan 23, 2024
Grant date	Jan 23, 2024

Abstract

A diamond coating includes a first diamond layer made of minute diamond particles and a second diamond layer made of coarse diamond particles: in a flank-face side diamond coating, a mean coat thickness d2 is not less than 3 μm and not more than 25 μm, a first diamond layer is formed on a surface side and a second diamond layer is formed on a tool base side: a rake-face side diamond coating is in a smaller range of 50 μm or 1/10 of a tool diameter from a tip of a base cutting-edge part; in the rake-face side diamond coating, a mean coat thickness d1 is a smaller one in a range not less than 0 μm and not more than 5.0 μm or a range less than d2: and a boundary part between the first diamond layer and the second diamond layer.

First claim

The invention claimed is:

1. A diamond-coated rotary cutting tool comprising a tool base made of hard metal and a diamond coating covering the surface thereof, wherein
the tool base is provided with a base rake-face, a base flank-face, and a base cutting-edge part provided on a ridge in which the base rake-face and the base flank-face cross,
the diamond coating forms: a flank-face side diamond coating, comprising a first diamond layer made of nanodiamond particles and a second diamond layer made of diamond particles which are larger than the diamond particles of the first diamond layer, wherein the flank-face side diamond coating covers a surface of the base flank-face and has a mean coat thickness d2 not less than 3 μm and not more than 25 μm; and a rake-face side diamond coating covering at least a prescribed region of the base rake-face, wherein a mean coat thickness d1 is a thickness of a smaller range of one of a range not less than 0 μm and not more than 5.0 μm or a range less than the mean coat thickness d2,
the flank-face side diamond coating is provided with the first diamond layer forming a surface thereof and the second diamond layer adjacent to the first diamond layer at a tool-base side,
the rake-face side diamond coating is provided on the prescribed region that is at least smaller one of a region 50 μm or 1/10 of a tool diameter from the base cutting-edge part of the base rake-face,
the diamond-coated rotary cutting tool is provided with a tool rake-face formed by a surface of the rake-face side diamond coating or a surface of the base rake-face and a following end surface of the flank-face side diamond coating; a tool flank-face formed by the surface of the flank-face side diamond coating; and a tool cutting-edge part formed at a ridge where the tool rake-face and the tool flank-face crosses, and
in a perpendicular cross section of the base cutting-edge part, where a straight line connecting a tool-rotation axis and the base cutting-edge part is a base line, a boundary part between the first diamond layer and the second diamond layer at the end surface of the flank-face side diamond coating is exposed at a side nearer to the base flank-face than an extended line of the base line,
wherein
on a perpendicular line to the base line at a position of 1 μm in a parallel direction to the base line from the boundary part to the tool base side, a ratio (L2/L1) of a length L1 of the second diamond layer and a length L2 of the first diamond layer satisfies 2≤(L2/L1)≤6.

2. The diamond-coated rotary cutting tool according to claim 1 , wherein
a mean particle size of diamond particles of the first diamond layer is less than 0.15 μm; and
a mean particle size of diamond particles of the second diamond layer is not less than 0.15 μm.

3. The diamond-coated rotary cutting tool according to claim 1 , wherein
a length ratio (a/b) is a rate of lengths (a) and (b) of the respective diamond particles observed on a cross section perpendicular to the surface of the tool base, where: the length (a) is along a perpendicular direction to the surface of the tool base, and the length (b) is along a parallel direction to the surface of the tool base,
the length ratio (a/b) of the diamond particles of the first diamond layer is less than 1.5, and
the length ratio (a/b) of the diamond particles of the second diamond layer is not less than 1.5.

4. The diamond-coated rotary cutting tool according to claim 1 , wherein
in a wave-form separation of Raman spectrum on a cross section of the diamond coating perpendicular to the surface of the tool base, an intensity (d) is a peak (d band) coming from a sp 3 hybrid orbital of diamond existing around 1332 cm −1 , and an intensity (G) is a peak (G band) coming from a sp3 hybrid orbital of graphite existing around 1580 cm −1 , and wherein
an intensity ratio (d/G) of the first diamond layer satisfies 0.1≤(d/G)≤0.8, and
the intensity ratio (d/G) of the second diamond layer satisfies 0.8≤(d/G).

Assignees

• Mitsubishi Materials Corp

Inventors

• Kubo Takuya
• Murata Kazuhisa
• TOMINAGA Akimitsu

Classifications

• B23B27/20 Primary

  with diamond bits {or cutting inserts} · CPC title

• B23B51/00

  Tools for drilling machines · CPC title

• B23C5/10

  Shank-type cutters, i.e. with an integral shaft · CPC title

• B23C5/1009

  Ball nose end mills · CPC title

• C23C16/271

  using hot filaments · CPC title