Diamond-coated cutting tools

Abstract

The present invention provides a cutting tool coated with a diamond film having a uniform thickness and high adhesion, a so-called diamond film coated cutting tool. [Solution] A diamond-coated cutting tool 1 is provided, in which at least the flank 3 and the rake face 4 are coated with a diamond film C, and the diamond-coated cutting tool 1 has a step d4 on the rake face 4 side with a width of 100 μm and a thickness of 10 μm or more and 13 μm or less in the thickness direction, starting from the ridge line 5 where the flank 3 and the rake face 4 intersect. Furthermore, the flank 3 side may have a step d3 with a width of 200 μm and a thickness of 3 μm or less in the thickness direction, with a surface roughness of 200 μm or less.

Description

Technical Field

[0001] The present invention relates to a cutting tool having a diamond film coated on its surface.

Background Art

[0002] Conventionally, a technique for coating a diamond film on the surface of a cutting tool has been widely known and is mainly used for the purpose of imparting high hardness and wear resistance. For example, Patent Document 1 discloses a method for manufacturing a tool using a diamond film. In this method, it is disclosed that the life of the tool can be significantly extended by forming a diamond film on the surface of a substrate using chemical vapor deposition (CVD) technology.

[0003] Also, Patent Document 2 discloses a pretreatment technique for improving the adhesion of a diamond film. Further, Patent Document 3 discloses a technique for further improving the cutting performance of a tool by optimizing the thickness and crystal structure of a diamond film.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the conventional diamond film coating technology has problems related to film peeling and adhesion to the substrate. Also, it has been pointed out that the cutting performance becomes unstable because the film thickness is not uniform. [[ID=4�]]

[0006] Therefore, the object of the present invention is to provide a cutting tool coated with a diamond film having a uniform thickness and high adhesion, a so-called diamond film coated cutting tool, in order to solve these problems. [Means for solving the problem]

[0007] The diamond-coated cutting tool of the present invention has a diamond film coated on the flank and rake surfaces, and has a step on the rake surface side with a width of 100 μm and a thickness of 10 μm to 13 μm, starting from the ridge where the flank and rake surfaces intersect.

[0008] Furthermore, a step may be provided on the relief surface side with a width of 200 μm starting from the ridge, such that the surface roughness is 200 μm or less within a width of 3 μm or less in the thickness direction. [Effects of the Invention]

[0009] The diamond-coated cutting tool of the present invention has a uniform thickness and high adhesion, which helps to maintain the sharpness of the cutting edge while suppressing the peeling of the diamond film on the rake face and flank face, thereby improving tool life. Furthermore, the flank face maintains wear resistance while reducing cutting resistance. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view of the cutting edge 2 of the diamond-coated cutting tool 1 before the diamond film is removed. [Figure 2] This is a schematic cross-sectional view of the cutting edge 2 of the diamond-coated cutting tool 1 after the diamond film C on the rake face 4 side has been removed. [Figure 3] This is a schematic cross-sectional view of the cutting edge 2 of the diamond-coated cutting tool 1 after the diamond film C on the relief surface 3 side has been removed. [Modes for carrying out the invention]

[0011] An embodiment of the diamond-coated cutting tool of the present invention is described below. The diamond-coated cutting tool according to the present invention has a diamond film coated on the flank and rake face. As the base material of the cutting tool, a material suitable for cutting, such as a hard alloy or high-speed tool steel, is used, which has high adhesion to the diamond film. The diamond film is uniformly coated on these base materials using chemical vapor deposition (CVD).

[0012] The diamond film formed by this CVD method imparts high hardness and wear resistance to the surface of the cutting tool, improving cutting performance. The diamond film only needs to cover the flank and rake face; it can also cover other areas such as the cutting edge, groove, margin, and outer corner.

[0013] A key feature of this invention is the control of the diamond film thickness and step height. On the rake face side, a step height of 10 μm to 13 μm is present in the thickness direction, extending over a width of 100 μm starting from the ridge. This step height setting reduces the cutting resistance at the cutting edge of the cutting tool, suppressing the peeling of the diamond film while maintaining the sharpness of the cutting edge. On the flank face side, a step height of 3 μm or less is present in the thickness direction, extending over a width of 200 μm starting from the ridge, so that the surface roughness is 200 μm or less. This reduces the load during cutting while maintaining the wear resistance of the tool.

[0014] A diamond-coated cutting tool, which is one embodiment of the present invention, will be described with reference to the drawings. Figure 1 shows a schematic cross-sectional view of the cutting edge 2 of the diamond-coated cutting tool 1 before the diamond film C according to the present invention is removed, Figure 2 shows a schematic cross-sectional view of the cutting edge 2 of the diamond-coated cutting tool 1 after the diamond film C on the relief surface 3 side has been removed, and Figure 3 shows a schematic cross-sectional view of the cutting edge 2 of the diamond-coated cutting tool 1 after the diamond film C on the rake surface 4 side has been removed.

[0015] Referring to Figures 1 to 3, the removal of the diamond film and any steps at the cutting edge 2 of the diamond-coated cutting tool 1 will be explained. Figure 1 is a schematic cross-sectional view of the cutting edge 2 of the diamond-coated cutting tool 1 before the diamond film C is removed, and the ridge line 5 where the flank 3 and rake face 4 intersect is depicted. In this state, the diamond film C is uniformly coated on both sides of the diamond-coated cutting tool (flank 3 and rake face 4).

[0016] Figure 2 shows the state after a portion of the diamond film C on the rake face 4 side has been removed, starting from the ridge line 5. This removal creates a step d4 in the film over a width W4 on the rake face 4 side. The step d4 is controlled to be within a range of 10 μm to 13 μm in the thickness direction. This setting reduces cutting resistance and maintains the sharpness of the cutting edge 2.

[0017] Figure 3 shows the state after the diamond film C on the flank surface 3 side has been removed, starting from the ridge line 5. On the flank surface 3 side, a step d3 of the film is formed over a width W3 such that the surface roughness is 200 μm or less within that range, and the thickness is controlled to be within a range of 3 μm or less in the thickness direction. This step d3 ensures the wear resistance of the tool and reduces the load during cutting. Thus, the structure shown in Figures 1 to 3 provides the diamond film coated cutting tool 1 with the effect of improving cutting performance and extending tool life.

[0018] Furthermore, setting the surface roughness of the relief face adjacent to the step d3 shown in Figure 3 to 0.2 μm or less is preferable in that it improves the wear resistance of the diamond film-coated cutting tool of the present invention while reducing cutting resistance.

[0019] In other words, the diamond-coated cutting tool of the present invention, with this configuration, significantly improves cutting performance and durability compared to conventional technology. In particular, since peeling of the diamond film at the cutting edge is suppressed, the tool life is extended and stable performance is achieved during cutting operations. Furthermore, the setting of steps on the flank and rake faces reduces cutting resistance, enabling efficient cutting.

[0020] In order to improve the adhesion of the diamond film in the cutting tool of the present invention, pretreatment of the substrate is indispensable. Specifically, the surface of the cutting tool is appropriately cleaned and subjected to physical or chemical surface modification treatment to enhance the adhesion between the diamond film and the substrate. For this pretreatment, for example, sandblasting treatment or etching treatment is often applied, whereby the diamond film can adhere firmly to the substrate and prevent the film from peeling off.

[0021] Furthermore, it is important to adjust the film-forming conditions for optimizing the crystal structure and film thickness uniformity of the diamond film. Specifically, by finely controlling parameters such as the type and flow rate of the reaction gas, film-forming temperature, and pressure in the CVD method, a uniform diamond film can be formed on the surface of the cutting tool, and the cutting performance of the tool can be improved.

Explanation of Reference Signs

[0022] 1 ··· Diamond film-coated cutting tool 2 ··· Cutting edge 3 ··· Relief face 4 ··· rake face 5 ··· Ridge line where the relief face and the rake face intersect C ··· Diamond film t3 ··· Removal thickness of the diamond film on the relief face side t4 ··· Removal thickness of the diamond film on the rake face side w3 ··· Removal width of the diamond film on the relief face side w4 ··· Removal width of the diamond film on the rake face side d3 ··· Step on the relief face side d4 ··· Step on the rake face side

Claims

1. A diamond-coated cutting tool having a diamond film coating on its flank and rake face, characterized in that, starting from the ridge where the flank and rake face intersect, the rake face side has a step with a width of 100 μm and a thickness of 10 μm or more and a thickness of 13 μm or less.

2. Furthermore, the diamond film coated cutting tool according to claim 1 is characterized in that, starting from the ridge line, the relief surface side has a step with a width of 200 μm, within a range of a width of 3 μm or less in the thickness direction, in which the surface roughness is 200 μm or less.

Images