Coated cutting tool and cutting tool having the same

Abstract

The coated tool of the present disclosure has a substrate and a diamond coating film on the substrate. The coated tool has a cutting edge. A region up to 300 μm from the cutting edge in a direction separating from the cutting edge is set as a first region, and a region of a distance of 300 μm or more and within 800 μm from the cutting edge is set as a second region. A plurality of dome-shaped protrusions exist on the surface of the diamond coating film. A protrusion having a circular equivalent diameter of 6 μm or more in the first region when viewed from directly above the first region is set as a first protrusion, and the number of the first protrusions per 1 mm 2 of the cutting edge is set as a first protrusion number. A protrusion having a circular equivalent diameter of 6 μm or more in the second region when viewed from directly above the second region is set as a second protrusion, and the number of the second protrusions per 1 mm 2 of the cutting edge is set as a second protrusion number. The first protrusion number is 30 or less, and the second protrusion number is more than the first protrusion number.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to Japanese Patent Application No. 2020-093451 filed May 28, 2020, the disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates to a coated tool used in cutting processing and a cutting tool provided with the coated tool. BACKGROUND

[0004] In Japanese Patent Application Publication No. H3-190605 (Patent Literature 1), it is described that a diamond coated cutting tool is smoothed using an abrasive brush. In addition, in Japanese Patent Application Publication No. 2010-70405 (Patent Literature 2), it is described that the number of abnormal growth diamond protrusion portions of the surface of a diamond film is set to 100 or less per 1 cm 2 of the diamond film formed on a substrate after a seed treatment of diamond powder. SUMMARY

[0005] The coated tool of the present disclosure has a substrate and a diamond coating film on the substrate. The coated tool has a first face, a second face, a land between the first face and the second face, and a cutting edge at at least a portion of the land. A region of the first face up to 300 pm from the cutting edge in a direction away from the cutting edge is set as a first region. A region of a distance of 300 pm or more and within 800 pm from the cutting edge away from the cutting edge is set as a second region. The diamond coating film is at least in the first region and the second region. There are a plurality of dome-shaped protrusions on the surface of the diamond coating film. A protrusion having an equivalent circle diameter of 6 pm or more in the first region when viewed from directly above the first region is set as a first protrusion, and the number of the first protrusions per 1 mm 2 of the first region is set as a first protrusion number. A protrusion having an equivalent circle diameter of 6 pm or more in the second region when viewed from directly above the second region is set as a second protrusion, and the number of the second protrusions per 1 mm 2 of the second region is set as a second protrusion number. The first protrusion number is 30 or less, and the second protrusion number is more than the first protrusion number. The cutting tool of the present disclosure has a tool holder having a length from a first end to a second end and having a tool pocket on the first end side, and the above-described coated tool in the tool pocket. BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 is a perspective view showing an example of the coated tool of the present disclosure.

[0007] Figure 2 is a drawing showing an example of the coated cutting tool of the present disclosure, and is a sectional view.

[0008] Figure 3 is a plan view showing an example of the cutting tool of the present disclosure.

[0009] Figure 4 is a plan view showing an example of the cutting tool of the present disclosure.

[0010] Figure 5 is a drawing showing an example of the cutting tool of the present disclosure, and is a perspective view of the front end enlarged. DETAILED DESCRIPTION

[0011] <Coated cutting tool>

[0012] Hereinafter, the coated cutting tool of the present disclosure will be described in detail using the drawings. However, in each drawing referred to below, only the main members required in the aspect of explaining the embodiments are simply shown for the convenience of explanation. Therefore, the coated cutting tool of the present disclosure can have any constituting members not shown in each drawing referred to. In addition, the dimensions of the members in each drawing do not accurately represent the dimensions of the actual constituting members and the dimension ratio of each member, and the like. These points are also the same in the cutting tool described later.

[0013] As shown in Figure 1 , the shape of the coated cutting tool 1 of the present disclosure can be, for example, a quadrilateral plate shape. Figure 1 The upper surface, that is, the first surface 5 in the

[0014] The coated cutting tool 1 has a lower surface, that is, a third surface (not shown) located at the opposite position of the first surface 5. The second surface 7 is connected to the first surface 5 and the third surface, respectively.

[0015] The coated cutting tool 1 of the present disclosure can also have a through-hole 9 that passes through the base 15 from the first surface 5 to the third surface.

[0016] The coated cutting tool 1 of the present disclosure has a cutting edge 13 located at at least a part of the edge line 11 (edge line portion) where the first surface 5 and the second surface 7 intersect. In other words, the cutting edge 13 is located at at least a part of the edge line 11 where the rake surface and the flank surface intersect.

[0017] In the coated cutting tool 1, the entire outer periphery of the first surface 5 can be the cutting edge 13, but the coated cutting tool 1 is not limited to this structure, and can be, for example, only one side of the quadrilateral rake surface or partially have the cutting edge 13. In addition, the coated cutting tool 1 of the present disclosure can be a drill shape.

[0018] The following will be explained taking a rectangular coated tool 1 shown in Figure 1 FIG. 1 as an example. In Figure 2 FIG. 2, a schematic view of a cross section of the coated tool 1 of the present disclosure is shown. Figure 2 The cross section is a cross section perpendicular to the surface of the substrate 15 of the coated tool 1 of the present disclosure. The diamond coating film 17 (diamond layer) is disposed on the substrate 15. The substrate 15 can be, for example, cemented carbide.

[0019] In the coated tool 1 of the present disclosure, a region in the first face 5 up to 300 pm from the cutting edge 13 toward a direction separating from the cutting edge 13 is set as a first region 19. In addition, a region separating from the cutting edge 13 by a distance of 300 pm or more and within 800 pm from the cutting edge 13 is set as a second region 21. Note that, in the definition of the above first region 19, "up to 300 pm" means that 300 pm is not included.

[0020] The diamond coating film 17 is disposed at least in the first region 19 and the second region 21. On the surface of the diamond coating film 17, a plurality of dome-shaped protrusions 23 are present. Note that, the dome-shaped protrusions 23 do not need to be circular in shape when the protrusions are viewed from above, and a polygonal shape is not excluded. In addition, the diameter of the protrusions 23 can be larger than the height of the protrusions 23 when the protrusions 23 are viewed in cross section as shown in Figure 2 FIG. 3. In addition, the protrusions 23 can have a shape similar to the upper half of a horizontally long ellipse when the protrusions 23 are viewed in cross section. If the protrusions 23 have such a shape, the chips move smoothly on the diamond coating film 17, and thus the cutting resistance is small. Therefore, the frictional heat generated when the chips contact the protrusions 23 is small.

[0021] In the present specification, the protrusions 23 in the first region 19 and having a circle-equivalent diameter of 6 pm or more when viewed from directly above the first region 19 are set as first protrusions 23a. In addition, the protrusions 23 in the second region 21 and having a circle-equivalent diameter of 6 pm or more when viewed from directly above the second region 21 are set as second protrusions 23b.

[0022] Note that, in Figure 2 FIG. 1, the protrusions 23 are present only in the first face 5, but the protrusions 23 can also be present in the second face 7.

[0023] The number of the first protrusions 23a per 1 mm 2 of the first face 5 is set as the first protrusion number 23an. In addition, the number of the second protrusions 23b per 1 mm 2The number of the second protrusions 23bn is set to be five times or more than the number of the first protrusions 23an. The coating tool 1 of the present disclosure has the number of the first protrusions 23an of 30 or less. The coating tool 1 of the present disclosure has the number of the second protrusions 23bn more than the number of the first protrusions 23an.

[0024] If the coating tool 1 has such a structure, the number of the first protrusions 23an per unit area is relatively small in the first region 19 located in the vicinity of the cutting edge 13, and the machined surface of the workpiece machined by the coating tool 1 is smooth. Also, the number of the second protrusions 23bn is relatively large in the second region 21 separated from the cutting edge 13, and thus the frictional heat generated when the cutting chips come into contact with the protrusions 23 is small, and in addition, the cooling property of the coating tool 1 is excellent, and the wear resistance is improved. By having both the first region 19 and the second region 21 having such a structure, the coating tool 1 of the present disclosure can smoothly machine the machined surface of the workpiece, and the machinability is excellent. In addition, the peeling resistance of the film (diamond film 17) is excellent, and the tool life is long.

[0025] The smaller the number of the first protrusions 23an, the smoother the machined surface of the workpiece can be. The coating tool 1 of the present disclosure can have the number of the first protrusions 23an of 20 or less. Also, the number of the first protrusions 23an can be 10 or less. The number of the first protrusions 23an can also be 0.

[0026] In addition, the number of the second protrusions 23bn of the coating tool 1 of the present disclosure can be five times or more than the number of the first protrusions 23an. The coating tool 1 having such a structure has smooth machinability and excellent tool life. Note that the number of the second protrusions 23bn can be eight times or less than the number of the first protrusions 23an.

[0027] The equivalent circle diameter of the protrusions 23 is preferably measured using a Keyence laser microscope (VK-X1000). The measurement is preferably performed by enlarging the surface of the diamond film 17 to 20 to 500 times. In the measurement of the number of the first protrusions 23an and the number of the second protrusions 23bn, 0.1 mm 2 The area is preferably as above.

[0028] <Method for manufacturing a coating tool>

[0029] A method for manufacturing a coating tool of the present disclosure will be described below. First, a substrate is prepared. The substrate uses cemented carbide, cermet, or the like.

[0030] Next, the substrate is subjected to etching treatment in the order of acid treatment and alkali treatment. Then, the substrate subjected to the etching treatment is immersed in a dispersion liquid of diamond particles, and subjected to ultrasonic treatment. If this process is performed, the density of the diamond particles obtained by film formation on the substrate can be improved. Thus, a diamond film having good adhesion can be obtained.

[0031] In addition, if the ultrasonic treatment is performed for a relatively long time, the main crystal phase of the hard material exposed on the surface of the base can be provided with unevenness, the anchoring effect can be easily exhibited, and the adhesion can be further improved.

[0032] The diamond powder added to the ultrasonic treatment solution can have an average particle diameter of 0.005 μm (5 nm) to 15 μm as measured by a laser scattering method. If the average particle diameter of the diamond powder is 0.1 μm or less, the number of projections of the entire coating is reduced. The diamond powder having an average particle diameter of 0.1 μm (100 nm) or more and 15 μm or less is inexpensive and has low manufacturing cost.

[0033] At this time, 2 to 12 g of diamond powder can be added to 1 (liter) of an organic or aqueous solution. By adjusting the average particle diameter and the amount of the diamond powder contained in the solution, the number of the first projections present in the first region and the second projections present in the second region can be adjusted.

[0034] For example, if the amount of the diamond powder is 8 g / l or less, the number of the first projections is relatively small. If the amount of the diamond powder exceeds 12 g / l, the number of the first projections is relatively large. If the amount of the diamond powder is less than 2 g / l, the second projections cannot be sufficiently formed.

[0035] In addition, the time for applying the ultrasonic wave can be set to 15 minutes to 4 hours. If the time for applying the ultrasonic wave is 2 hours or more, the adhesion of the coating is particularly excellent.

[0036] In addition, the number of the first projections present in the first region and the second projections present in the second region can be adjusted by controlling the film formation conditions described later in addition to the amount of the diamond powder.

[0037] As the film formation method of the diamond coating, for example, a CVD method of a hot filament method or a plasma method can be used. In order to obtain substantially hemispherical projections, the film formation time can be set to 10 hours or more.

[0038] In the CVD method, the base is disposed in a chamber, heated to a temperature of 850°C to 930°C, and a film formation gas is circulated in the chamber. The film formation gas contains, for example, hydrogen and methane gas.

[0039] The time during which the base is heated to 850°C to 930°C and the film formation gas is circulated is referred to as the film formation time. The longer the film formation time, the larger the projections of the diamond coating, and thus the coating tool having the first projections and the second projections can be easily obtained.

[0040] Furthermore, the larger the average particle size of the diamond powder, the greater the protrusion can be formed in a shorter film-forming time. For example, when the average particle size of the diamond powder is 0.005 μm (5 nm) to 10 μm, if the film-forming time is set to 10 to 20 hours, the coated tool of this disclosure is obtained.

[0041] <Cutting Tools>

[0042] The cutting tools of this disclosure will now be described using the accompanying drawings. Figure 3 As shown, the cutting tool 101 of this disclosure is, for example, from the first end ( Figure 3 The upper end of the middle) faces the second end ( Figure 3 A rod-shaped body extending from the lower end of the middle. For example... Figure 3 As shown, the cutting tool 101 includes a tool holder 105 having a tool groove 103 on the first end side (front end side) and the aforementioned coated tool 1 located in the tool groove 103.

[0043] A clamping member 107 is inserted into the through hole 9 of the coated tool 1. The cutting tool 101 is equipped with the coated tool 1 of this disclosure, and therefore can perform long-term stable cutting operations.

[0044] The tool groove 103 is a portion for mounting the coated tool 1, and has a sitting surface parallel to the lower surface of the tool holder 105 and a restraining side inclined relative to the sitting surface. In addition, the tool groove 103 has an opening at the first end side of the tool holder 105.

[0045] A coated cutter 1 is disposed in the cutter groove 103. At this time, the lower surface of the coated cutter 1 can directly contact the cutter groove 103, or a sheet (not shown) can be sandwiched between the coated cutter 1 and the cutter groove 103.

[0046] The coated tool 1 is mounted on the tool holder 105 such that at least a portion of the part used as the cutting edge 13 at the intersection of the rake face and the flank face protrudes outward from the tool holder 105. The coated tool 1 can be mounted on the tool holder 105 by a fixing screw instead of the clamping member 107. That is, the coated tool 1 can be mounted on the tool holder 105 by inserting the fixing screw into the through hole 9 of the coated tool 1, inserting the tip of the fixing screw into the threaded hole (not shown) formed in the tool groove 103, and screwing the threads together.

[0047] For the tool holder 105, steel, cast iron, and other materials can be used. High-toughness steel can also be used for these components.

[0048] exist Figure 3In the present embodiment, a cutting tool 101 used in so-called turning processing is exemplified. As the turning processing, for example, internal diameter processing, external diameter processing, grooving processing, face processing, and the like can be exemplified. Note that, as the cutting tool 101, it is not limited to the cutting tool used in the turning processing. For example, the coated cutting tool 1 of the above-described embodiment can also be used in the cutting tool 101 used in rotary cutting processing.

[0049] The cutting tool of the present disclosure is described based on a preferred example thereof, i.e., an example of a non-reusable drill bit. Figure 4 is a schematic side view showing a cutting tool 201, i.e., a non-reusable drill bit 201. As shown in Figure 4 , the non-reusable drill bit 201 has the coated cutting tool 1 installed at the front end of a tool body 202 (a tool holder) that becomes a rotation axis O at the center.

[0050] Here, the tool holder 202 is in a substantially cylindrical shape, has the rotation axis O shown by a broken line in Figure 4 , and has a shank portion 208 for fixing itself to a machine tool at the rear end side, and has a chip discharge groove 209 that spirally formed at a position on the front end side of the shank portion 208 to discharge chips from the front end to the rear end of the tool holder 202. In addition, a tool 210 is provided at the front end portion of the tool holder 202, and the coated cutting tool 1 is installed at the tool 210.

[0051] Then, the non-reusable drill bit 201 is rotated to process a workpiece (not shown).

[0052] In Figure 5 , a cutting tool 301 for milling processing is shown. The coated cutting tool 1 is installed at a tool 310 provided at a tool holder 302. In this example, three coated cutting tools 1 are installed at the front end of the tool holder 302.

[0053] Embodiment

[0054] Hereinafter, the coated cutting tool of the present disclosure is described. The substrate was produced as follows. A tungsten carbide (WC) powder having an average particle diameter of 0.5 μm was mixed with a cobalt (Co) powder added at a rate of 10 mass%, a titanium carbide (TiC) powder added at a rate of 0.2 mass%, and a chromium carbide (Cr3C2) powder added at a rate of 0.8 mass%, and was molded into a rectangular shape and fired.

[0055] After that, the sintered body was cleaned with distilled water / organic solution. Next, the substrate was subjected to etching treatment in the order of acid treatment and alkali treatment, and the Co metal of the surface layer was removed.

[0056] Next, the substrate was immersed in an organic solution to which diamond powder having an average particle diameter shown in Table 1 was added at a ratio shown in Table 1, and ultrasonic waves were applied for 3 hours. Thereafter, the organic solution on the surface of the substrate was removed and dried.

[0057] The substrate subjected to these processes was subjected to film formation for a film formation time shown in Table 1. Note that a mixed gas of hydrogen gas and methane gas was used as the film formation gas. The entire mixed gas was mixed with methane gas at 0.5 to 2.0 vol%.

[0058] After the film formation, in Sample No. 8 shown in Table 1, surface polishing treatment was performed using brush polishing treatment.

[0059] The first region and the second region of the coated tool thus obtained were enlarged to 500 times, and the projections present in each region were observed. The number of first projections and the number of second projections are shown in Table 1.

[0060] The coated tool thus obtained was set in and fixed to the tool pocket of a tool holder, and a cutting test based on milling was performed under the following conditions. In addition, the machined surface roughness of the workpiece was evaluated after the test.

[0061] [Cutting Test]

[0062] Cutting method: shoulder cutting (milling)

[0063] Workpiece: ADC12

[0064] Cutting speed: 800 m / min

[0065] Feed: 0.08 mm / tooth

[0066] Longitudinal cut: 1.5 mm

[0067] Transverse cut: 15 mm

[0068] Cutting state: wet

[0069] Evaluation method: Whether or not the diamond coating film of the cutting edge of the coated tool was peeled off, and the machined surface roughness of the workpiece were measured at the time when 100 m of cutting was performed.

[0070] [Table 1]

[0071]

[0072] The samples No. 1, 6, 8, 9, 10, 11, 12, 13 having no structure of the coated tool of the present disclosure generated large film peeling, chipping, damage, and the like in the milling process, the machined surface of the workpiece was white turbid, and the surface roughness was rough. The coated tools of the present disclosure of the samples No. 2, 3, 4, 5, 7 suppressed abnormal damage such as chipping and the like, and the surface roughness of the machined surface was also good. In the samples No. 2, 4, 7, although there was peeling, it was confirmed that the peeling was in a very narrow region. Also, with respect to the samples No. 3, 5, there was no film peeling, the surface roughness was Ra = 0.5 μm or less, and the cutting performance was excellent.

[0073] The coated tool of the present disclosure and the cutting tool having the same described above are one example, and can have a different structure without departing from the gist of the present application.

[0074] Explanation of Reference Numerals

[0075] 1 Coated tool

[0076] 5 First surface

[0077] 7 Second surface

[0078] 9 Through hole

[0079] 11 Ridges

[0080] 13 Cutting edge

[0081] 15 Base

[0082] 17 Diamond coating film (diamond layer)

[0083] 19 First region

[0084] 21 Second region

[0085] 23 Protrusion

[0086] 23a First protrusion

[0087] 23an Number of first protrusions

[0088] 23b Second protrusion

[0089] 23bn Number of second protrusions

[0090] 101, 201, 301 Cutting tool

[0091] 103, 210, 310 Tool pocket

[0092] 105, 202, 302 Tool holder

[0093] 107 Clamping member

Claims

1. A coated cutting tool having a substrate and a diamond coating disposed on the substrate, wherein, This coated cutting tool has the following characteristics: First impression; Second side; The ridge portion is located between the first surface and the second surface; as well as A cutting edge, located at least a portion of the ridge portion. In the case where the region on the first surface extending 300 μm from the cutting edge toward the direction separating from the cutting edge is designated as the first region, and the region extending 300 μm or more but less than 800 μm from the cutting edge as the starting point is designated as the second region,... The diamond coating is located at least in the first region and the second region. Multiple dome-shaped protrusions exist on the surface of the diamond coating. When viewed from directly above the first region, a protrusion with an equivalent circle diameter of 6 μm or more in the first region is designated as a first protrusion, and the number of such first protrusions per 1 mm² is designated as a first protrusion number. Similarly, when viewed from directly above the second region, a protrusion with an equivalent circle diameter of 6 μm or more in the second region is designated as a second protrusion, and the number of such second protrusions per 1 mm² is designated as a second protrusion number. The number of the first protrusion is 30 or less. The second number of protrusions is greater than the first number of protrusions. The protrusion has a convex curved shape in a cross section orthogonal to the first surface.

2. The coated cutting tool according to claim 1, wherein, The number of the first protrusion is 20 or less.

3. The coated cutting tool according to claim 1 or 2, wherein, The number of the second protrusion is more than five times the number of the first protrusion.

4. The coated cutting tool according to claim 1 or 2, wherein, The number of the first protrusion is 5 or more. The number of the second protrusion is more than five times the number of the first protrusion.

5. The coated cutting tool according to claim 1 or 2, wherein, In a cross section orthogonal to the first surface, the diameter of the protrusion, as indicated by a direction parallel to the first surface, is greater than the height of the protrusion, as indicated by a direction orthogonal to the first surface.

6. The coated cutting tool according to claim 5, wherein, In a cross section orthogonal to the first surface, the protrusion is a transversely elongated semi-ellipsoidal shape.

7. The coated cutting tool according to claim 1 or 2, wherein, The protrusion is located on the first surface and not on the second surface.

8. A cutting tool, wherein, The cutting tool has: A tool holder having a length from a first end to a second end, and having a tool groove located on the side of the first end; and The coated cutting tool according to any one of claims 1 to 7, which is located in the cutting groove.

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