Coated and cutting tools

Abstract

A coated tool according to the present disclosure comprises a substrate, and a coating layer positioned on the substrate. The coated tool includes: a first surface having a rake face; a second surface having a flank face; and a ridge portion positioned between the first surface and the second surface. A cutting edge is positioned in at least a part of the ridge portion. The cutting edge has a third surface in at least a part thereof. The coating layer includes at least a second coating layer positioned on the second surface, and a third coating layer positioned on the third surface. If adhesion strength between the second coating layer and the second surface is represented as second adhesion strength, and adhesion strength between the third coating layer and the third surface is represented as third adhesion strength, the third adhesion strength is smaller than the second adhesion strength.

Description

[Technical field]

[0001] The present disclosure relates to coated tools and cutting tools. [Background technology]

[0002] As a tool used in cutting processes such as turning and milling, there are known coated tools in which the surface of a base material such as cemented carbide, cermet, ceramics, etc. is coated with a coating layer to improve wear resistance, etc. (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-3284 A Summary of the Invention

[0004] A coated tool according to one embodiment of the present disclosure is a coated tool having a base and a coating layer located on the base. The coated tool has a first surface having a rake face, a second surface having a flank face, and a ridge portion located between the first surface and the second surface. A cutting edge is located at least in a part of the ridge portion. The cutting edge has at least a third surface. The coating layer has at least a second coating layer located on the second surface and a third coating layer located on the third surface. When the adhesion between the second coating layer and the second surface is defined as a second adhesion force and the adhesion between the third coating layer and the third surface is defined as a third adhesion force, the third adhesion force is smaller than the second adhesion force.

[0005] A cutting tool according to one aspect of the present disclosure includes a rod-shaped holder having a pocket at an end thereof and the coated tool described above positioned within the pocket. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view showing an example of a coated tool according to an embodiment. [Diagram 2]FIG. 2 is a side cross-sectional view showing an example of a coated tool according to an embodiment. [Diagram 3] FIG. 3 is a schematic enlarged view of part III shown in FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view showing another example of the configuration of the coating layer. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing another example of the configuration of the coating layer. [Figure 6] FIG. 6 is a schematic enlarged view of portion VI shown in FIG. [Figure 7] FIG. 7 is a schematic enlarged view of part VII shown in FIG. [Figure 8] FIG. 8 is a front view showing an example of a cutting tool according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, a detailed description will be given of a form for carrying out a coated tool and a cutting tool according to the present disclosure (hereinafter, referred to as an "embodiment") with reference to the drawings. Note that the coated tool and the cutting tool according to the present disclosure are not limited to the embodiment. Moreover, each embodiment can be appropriately combined as long as the processing contents are not contradictory. Moreover, the same parts in each of the following embodiments are given the same reference numerals, and duplicated explanations will be omitted.

[0008] In addition, in the embodiments described below, expressions such as "constant", "orthogonal", "vertical" and "parallel" may be used, but these expressions do not necessarily mean "constant", "orthogonal", "vertical" and "parallel" strictly. In other words, each of the above expressions allows for deviations due to, for example, manufacturing accuracy and installation accuracy.

[0009] There are known coated tools in which the surface of a substrate made of cemented carbide, cermet, ceramics, etc. is coated with a coating layer to improve wear resistance, etc. However, there is room for further improvement in this type of coated tool in terms of realizing a longer life.

[0010] <Coated tools> Fig. 1 is a perspective view showing an example of a coated tool according to an embodiment. As shown in Fig. 1, the coated tool 1 according to the embodiment may have a tip body 2 and a cutting edge portion 3. The coated tool 1 according to the embodiment has, for example, a hexahedral shape in which the upper and lower surfaces (surfaces intersecting with the Z-axis shown in Fig. 1) are parallelogram shapes.

[0011] The coated tool 1 has a first surface 6 (here, an upper surface), a second surface 7 (here, a side surface) connected to the first surface 6, and a ridge portion 8 located between the first surface 6 and the second surface 7. The first surface 6 has a scooping surface for scooping up chips generated by cutting. In addition, the second surface 7 has a flank surface.

[0012] The first surface 6 has a plurality of (four here) corners 61 in plan view. Here, the corners refer to areas including the corners of the first surface 6. A cutting edge 11 is located on a ridge line 8 of at least one of the plurality of corners 61. The coated tool 1 cuts a workpiece by bringing the cutting edge 11 into contact with the workpiece.

[0013] (Chip body 2) The tip body 2 is formed of, for example, a cemented carbide. The cemented carbide contains W (tungsten), specifically WC (tungsten carbide). The cemented carbide may also contain at least one of Ni (nickel) and Co (cobalt). The tip body 2 may also be formed of a cermet. The cermet contains, for example, Ti (titanium), specifically TiC (titanium carbide) or TiN (titanium nitride). The cermet may also contain Ni or Co.

[0014] A seat 4 for attaching the cutting edge portion 3 may be located in one of the locations of the tip body 2 that corresponds to the corner 61 of the coated tool 1. A through hole 5 that passes through the tip body 2 from top to bottom may be located in the center of the tip body 2. A screw 75 for attaching the coated tool 1 to a holder 70 described later is inserted into the through hole 5 (see FIG. 7).

[0015] (Cutting edge 3) The cutting edge portion 3 is attached to the seat surface 4 of the tip body 2, and is thereby integrated with the tip body 2. The cutting edge portion 3 constitutes one of a plurality of corner portions 61 of the coated tool 1. The cutting edge portion 3 also constitutes the first surface 6, the second surface 7, and a part of the ridge portion 8 described above. The cutting edge 11 is located on at least a part of the ridge portion 8 of the cutting edge portion 3.

[0016] The configuration of the cutting edge portion 3 will be described with reference to Fig. 2. Fig. 2 is a side cross-sectional view showing an example of a coated tool 1 according to an embodiment. As shown in Fig. 2, the cutting edge portion 3 has a base body 10 and a coating layer 20.

[0017] (Base 10) The substrate 10 may be a cemented carbide, a cermet, or a ceramic. It may also contain a plurality of boron nitride particles. In the embodiment, the substrate 10 is a cubic boron nitride (cBN) sintered body and may contain a plurality of cubic boron nitride particles. The substrate 10 may have a bonding phase containing TiN, Al, Al2O3, or the like between the plurality of boron nitride particles. The plurality of boron nitride particles are firmly bonded by such a bonding phase. The substrate 10 does not necessarily have to have a bonding phase. In the above embodiment, the substrate 10 is located at the cutting edge portion 3, but the substrate 10 may be the main body 2 and the cutting edge portion 3. In other words, for example, a rectangular substrate 10 may be used.

[0018] A third surface 9 continuous with the first surface 6 and the second surface 7 is located on at least a portion of the cutting edge 11. The third surface 9 is, for example, a C-surface (chamfered surface) obtained by cutting the corner between the first surface 6 and the second surface 7 obliquely and linearly. The third surface 9 may also be an R-surface (rounded surface) obtained by rounding the corner between the first surface 6 and the second surface 7.

[0019] A substrate 30 made of, for example, cemented carbide or cermet may be located on the lower surface of base 10. In this case, base 10 is joined to seating surface 4 of chip body 2 via substrate 30 and bonding material 40. Bonding material 40 is, for example, brazing material. In the portion of chip body 2 other than seating surface 4, base 10 may be joined to chip body 2 via bonding material 40.

[0020] (Coating layer 20) The coating layer 20 is applied to the base 10 for the purpose of improving the wear resistance, heat resistance, etc. of the cutting edge portion 3. In the example of Fig. 2, the coating layer 20 is located on both the tip body 2 and the base 10, but it is sufficient that the coating layer 20 is located at least on the base 10. When the coating layer 20 is located on the side surface of the base 10 corresponding to the second surface 7 of the cutting edge portion 3, the second surface 7 has high wear resistance and heat resistance.

[0021] The coating layer 20 has a first coating layer located on the first surface 6, a second coating layer located on the second surface 7, and a third coating layer located on the third surface 9. If the adhesion between the first coating layer and the first surface 6 is defined as the first adhesion force, the adhesion between the second coating layer and the second surface 7 is defined as the second adhesion force, and the adhesion between the third coating layer and the third surface 9 is defined as the third adhesion force, in the coated tool 1 according to the embodiment, the third adhesion force is smaller than the second adhesion force.

[0022] The inventors of the present application have found that the life of the coated tool 1 can be extended by relatively reducing the adhesion of the third coating layer located on the third surface 9. One of the reasons for this is that in the case of processing in which a thermal shock is applied to the coated tool 1, such as when the coated tool 1 performs intermittent cutting while in contact with a coolant, if the adhesion of the third coating layer is strong, the third coating layer will be damaged together with the substrate 10, which is the base material, when it is destroyed.

[0023] Therefore, in the coated tool 1 according to the embodiment, the third adhesion force is set to be smaller than the first adhesion force and the second adhesion force. The coated tool 1 having such a configuration can suppress damage to the substrate 10 at the third surface 9. Therefore, the coated tool 1 according to the embodiment can achieve a longer life.

[0024] In addition, since the third coating layer has a relatively small adhesive strength, it is removed from the third surface 9 when the coated tool 1 is first used (for example, when used for the first time) as the workpiece is cut. Therefore, according to the coated tool 1, it is easy to determine whether the tool is unused or used by checking the presence or absence of the third coating layer. It is preferable that the coating layer 20 has a color different from that of the base body 10. In this case, it is easy to visually determine whether the tool is unused or used.

[0025] The third adhesion force may be equal to or less than 40 N. According to this configuration, the adhesion force between the third coating layer and the third surface 9 can be appropriately reduced, and the life of the coated tool 1 can be appropriately extended.

[0026] Moreover, the second adhesion force may be equal to or greater than 80 N. With this configuration, the wear resistance and heat resistance of the second surface 7 can be appropriately increased.

[0027] The first to third adhesion strengths may be measured by, for example, a scratch test.

[0028] The thickness of the third coating layer may be thinner than the thicknesses of the first coating layer and the second coating layer. By reducing the thickness of the third coating layer, damage to the substrate 10 when the coating layer 20 is broken is suppressed. Therefore, the coated tool 1 having such a configuration can have a further longer life. For example, the thickness of the first coating layer and the second coating layer may be 0.5 μm or more and 5.0 μm or less. Also, the thickness of the third coating layer may be 0.01 μm or more and less than 5.0 μm.

[0029] (Configuration of Covering Layer 20) In the embodiment, the covering layer 20 has a high adhesion layer 20A and a low adhesion layer 20B. The high adhesion layer 20A is located on the substrate 10, and the low adhesion layer 20B entirely covers the substrate 10 and the high adhesion layer 20A. The low adhesion layer 20B may be located at least on the third surface 9.

[0030] The high adhesion layer 20A is a film formed by, for example, a PVD method (physical vapor deposition method). A specific configuration example of the high adhesion layer 20A will be described later.

[0031] The low adhesion layer 20B is a film having a smaller adhesion to the substrate 10 than the high adhesion layer 20A. For example, the low adhesion layer 20B may be a resin layer. For example, acrylic resin, ultraviolet curing resin, epoxy resin, etc. may be used as the low adhesion layer 20B.

[0032] The low adhesion layer 20B may be a paint such as poster color or acrylic gouache. The low adhesion layer 20B may be a film formed by a CVD method (chemical vapor deposition method). The low adhesion layer 20B may be a PVD film in which the bias conditions and the like are adjusted so that the adhesion is smaller than that of the high adhesion layer 20A. The low adhesion layer 20B may be a Ti-based PVD film. Ti has poor wettability with the base 10 according to the embodiment, and has low adhesion to the base 10. For this reason, by using Ti as the low adhesion layer 20B, it is possible to obtain a low adhesion layer 20B having a lower adhesion than the high adhesion layer 20A. In addition, when the low adhesion layer 20B is a compound such as a nitride, carbide, or carbonitride of Ti, the thermal expansion difference with the base 10 is large and the residual stress is large, so that the adhesion can be reduced.

[0033] Next, the configurations of the first to third coating layers in the coating layer 20 will be described with reference to Fig. 3. Fig. 3 is a schematic enlarged view of part III shown in Fig. 2.

[0034] As shown in FIG. 3, the coating layer 20 has a first coating layer 201 located on the first surface 6, a second coating layer 202 located on the second surface 7, and a third coating layer 203 located on the third surface 9.

[0035] The first coating layer 201 and the second coating layer 202 have a high adhesion layer 20A and a low adhesion layer 20B. That is, the first coating layer 201 has a high adhesion layer 20A located on the first surface 6, and a low adhesion layer 20B located on this high adhesion layer 20A. In addition, the second coating layer 202 has a high adhesion layer 20A located on the second surface 7, and a low adhesion layer 20B located on this high adhesion layer 20A.

[0036] On the other hand, the third coating layer 203 has only the low adhesion layer 20B out of the high adhesion layer 20A and the low adhesion layer 20B. That is, the low adhesion layer 20B in the third coating layer 203 is in contact with the third surface 9 and is exposed on the surface of the third coating layer 203.

[0037] In this way, the third coating layer 203 does not have the high adhesion layer 20A, and the low adhesion layer 20B contacts the third surface 9 without the high adhesion layer 20A. Therefore, the third coating layer 203 has a smaller adhesion to the substrate 10 than the first coating layer 201 and the second coating layer 202.

[0038] 4 and 5 are schematic cross-sectional views showing another example of the configuration of the coating layer 20. As shown in FIG. 4, the first coating layer 201 may have only the low adhesion layer 20B of the high adhesion layer 20A and the low adhesion layer 20B, similarly to the third coating layer 203. In this case, the adhesion (third adhesion) between the third coating layer 203 and the third surface 9 may be equal to the adhesion (first adhesion) between the first coating layer 201 and the first surface 6. In this way, the adhesion (third adhesion) between the third coating layer 203 and the third surface 9 only needs to be smaller than the adhesion (second adhesion) between the second coating layer 202 and the second surface 7.

[0039] 5, both the high adhesion layer 20A and the low adhesion layer 20B do not have to be located on the first surface 6. In other words, the base 10 may be exposed on the first surface 6.

[0040] The inventors of the present application have clarified that the durability of the coated tool 1 is improved when the coating layer 20 is not provided on the first surface 6, which corresponds to the rake face, compared to when the coating layer 20 is provided on the first surface 6, which corresponds to the rake face. Accordingly, the coated tool 1 in which the first surface 6, which corresponds to the rake face, is exposed has high durability.

[0041] Moreover, the thickness of the third coating layer 203 may be thinner in a region closer to the first surface 6 than in a region closer to the second surface 7. In other words, the thickness of the third coating layer 203 may gradually increase from the first surface 6 toward the second surface 7. The coated tool 1 having such a configuration has a good balance of fracture resistance, wear resistance, and heat resistance.

[0042] (Specific configuration of high adhesion layer 20A) Next, a specific configuration of the high adhesion layer 20A will be described with reference to Fig. 6. Fig. 6 is a schematic enlarged view of part VI shown in Fig. 3.

[0043] As shown in FIG. 6, the high adhesion layer 20A has at least a hard layer 21. The hard layer 21 may have one or more metal nitride layers. The hard layer 21 is a layer having superior wear resistance compared to the metal layer 22. The hard layer 21 may be a single layer. Alternatively, a plurality of metal nitride layers may be overlapped. Alternatively, the hard layer 21 may have a laminated portion 23 in which a plurality of metal nitride layers are laminated, and a third metal nitride layer 24 located on the laminated portion 23. The configuration of the hard layer 21 will be described later.

[0044] (metal layer 22) The high adhesion layer 20A may also have a metal layer 22. The metal layer 22 is located between the substrate 10 and the hard layer 21. Specifically, the metal layer 22 contacts the substrate 10 on one side and contacts the hard layer 21 on the other side.

[0045] The metal layer 22 has higher adhesion to the substrate 10 than the hard layer 21. Examples of metal elements having such properties include Zr, V, Cr, W, Al, Si, and Y. The metal layer 22 contains at least one of the above metal elements.

[0046] Note that simple elements of Ti, Zr, V, Cr, and Al are not used as the metal layer 22. These elements all have low melting points and low oxidation resistance, making them unsuitable for use in cutting tools. Also, simple elements of Hf, Nb, Ta, and Mo have low adhesion to the substrate 10. However, this does not apply to alloys containing Ti, Zr, V, Cr, Ta, Nb, Hf, and Al.

[0047] The metal layer 22 may be an Al-Cr alloy layer containing an Al-Cr alloy. Such a metal layer 22 has particularly high adhesion to the substrate 10, and is therefore highly effective in improving the adhesion between the substrate 10 and the high adhesion layer 20A.

[0048] When the metal layer 22 is an Al-Cr alloy layer, the Al content in the metal layer 22 may be greater than the Cr content in the metal layer 22. For example, the composition ratio (atomic %) of Al to Cr in the metal layer 22 may be 70:30. With such a composition ratio, the adhesion between the substrate 10 and the metal layer 22 is higher.

[0049] The metal layer 22 may contain components other than the above metal elements (Zr, V, Cr, W, Al, Si, Y). However, from the viewpoint of adhesion to the substrate 10, the metal layer 22 may contain at least 95 atomic % or more of the above metal elements in total. More preferably, the metal layer 22 may contain at least 98 atomic % or more of the above metal elements in total. For example, when the metal layer 22 is an Al-Cr alloy layer, the metal layer 22 may contain at least Al and Cr in total of 95 atomic % or more. Furthermore, the metal layer 22 may contain at least Al and Cr in total of 98 atomic % or more. The ratio of the metal components in the metal layer 22 can be identified by, for example, analysis using EDS (energy dispersive X-ray spectrometry).

[0050] Moreover, since Ti has poor wettability with the base 10 according to the embodiment, it is preferable that the metal layer 22 contains as little Ti as possible from the viewpoint of improving adhesion with the base 10. Specifically, the Ti content in the metal layer 22 may be 15 atomic % or less.

[0051] In this manner, in the coated tool 1 according to the embodiment, the metal layer 22, which has higher wettability with the substrate 10 than the hard layer 21, is provided between the substrate 10 and the hard layer 21, thereby improving the adhesion between the substrate 10 and the high adhesion layer 20A. Since the metal layer 22 also has high adhesion with the hard layer 21, the hard layer 21 is unlikely to peel off from the metal layer 22.

[0052] Moreover, cBN used as the substrate 10 is an insulator. As an insulator, cBN has room for improvement in adhesion with a film formed by a PVD (physical vapor deposition) method. In contrast, in the coated tool 1 according to the embodiment, by providing a conductive metal layer 22 on the surface of the substrate 10, adhesion between the hard layer 21 formed by PVD and the metal layer 22 is high.

[0053] (hard layer 21) Next, the configuration of the hard layer 21 will be described with reference to Fig. 7. Fig. 7 is a schematic enlarged view of part VII shown in Fig. 6.

[0054] As shown in FIG. 7, the hard layer 21 has a laminated portion 23 located on the metal layer 22, and a third metal nitride layer 24 located on the laminated portion 23.

[0055] The laminated portion 23 has a plurality of first metal nitride layers 23a and a plurality of second metal nitride layers 23b. The laminated portion 23 has a configuration in which the first metal nitride layers 23a and the second metal nitride layers 23b are alternately laminated.

[0056] The thickness of each of the first metal nitride layer 23a and the second metal nitride layer 23b may be 50 nm or less. In this way, by forming the first metal nitride layer 23a and the second metal nitride layer 23b thin, the residual stress of the first metal nitride layer 23a and the second metal nitride layer 23b is small. As a result, for example, peeling or cracking of the first metal nitride layer 23a and the second metal nitride layer 23b is less likely to occur, and the durability of the high adhesion layer 20A is high.

[0057] The first metal nitride layer 23a is a layer in contact with the metal layer 22, and the second metal nitride layer 23b is formed on the first metal nitride layer 23a.

[0058] The first metal nitride layer 23a and the second metal nitride layer 23b may contain the metal contained in the metal layer 22.

[0059] For example, suppose that metal layer 22 contains two types of metals (herein referred to as a "first metal" and a "second metal"). In this case, first metal nitride layer 23a contains nitrides of the first metal and a third metal. The third metal is a metal not contained in metal layer 22. In addition, second metal nitride layer 23b contains nitrides of the first metal and the second metal.

[0060] For example, in the embodiment, the metal layer 22 may contain Al and Cr. In this case, the first metal nitride layer 23a may contain Al. Specifically, the first metal nitride layer 23a may be an AlTiN layer containing AlTiN, which is a nitride of Al and Ti. Also, the second metal nitride layer 23b may be an AlCrN layer containing AlCrN, which is a nitride of Al and Cr.

[0061] In this manner, by positioning the first metal nitride layer 23a containing the metal contained in the metal layer 22 on the metal layer 22, the adhesion between the metal layer 22 and the hard layer 21 is high. This makes it difficult for the hard layer 21 to peel off from the metal layer 22, and therefore the durability of the high adhesion layer 20A is high.

[0062] The first metal nitride layer 23a, i.e., the AlTiN layer, has excellent adhesion to the metal layer 22, for example, in wear resistance. The second metal nitride layer 23b, i.e., the AlCrN layer, has excellent heat resistance and oxidation resistance, for example. In this way, the high adhesion layer 20A includes the first metal nitride layer 23a and the second metal nitride layer 23b having different compositions, and thus the characteristics of the hard layer 21, such as wear resistance and heat resistance, can be controlled. This can extend the tool life of the coated tool 1. For example, in the hard layer 21 according to the embodiment, mechanical properties such as adhesion to the metal layer 22 and wear resistance can be improved while maintaining the excellent heat resistance of AlCrN.

[0063] The laminated portion 23 may be formed by, for example, an arc ion plating method (AIP method). The AIP method is a method in which a target metal (here, an AlTi target and an AlCr target) is evaporated by using an arc discharge in a vacuum atmosphere, and then combined with N2 gas to form a metal nitride (here, AlTiN and AlCrN). The metal layer 22 may also be formed by the AIP method.

[0064] The third metal nitride layer 24 may be located on the laminated portion 23. Specifically, the third metal nitride layer 24 contacts the second metal nitride layer 23b of the laminated portion 23. The third metal nitride layer 24 is, for example, a metal nitride layer containing Ti and Al (AlTiN layer) like the first metal nitride layer 23a.

[0065] The thickness of the third metal nitride layer 24 may be thicker than the thicknesses of the first metal nitride layer 23a and the second metal nitride layer 23b. Specifically, when the thicknesses of the first metal nitride layer 23a and the second metal nitride layer 23b are 50 nm or less as described above, the thickness of the third metal nitride layer 24 may be 1 μm or more. For example, the thickness of the third metal nitride layer 24 may be 1.2 μm.

[0066] As a result, for example, when the friction coefficient of the third metal nitride layer 24 is low, the adhesion resistance of the coated tool 1 can be improved. Also, for example, when the hardness of the third metal nitride layer 24 is high, the wear resistance of the coated tool 1 can be improved. Also, for example, when the oxidation onset temperature of the third metal nitride layer 24 is high, the oxidation resistance of the coated tool 1 can be improved.

[0067] Furthermore, the thickness of third metal nitride layer 24 may be thicker than the thickness of laminated portion 23. Specifically, in the embodiment, when the thickness of laminated portion 23 is 0.5 μm or less, the thickness of third metal nitride layer 24 may be 1 μm or more. For example, when the thickness of laminated portion 23 is 0.3 μm, the thickness of third metal nitride layer 24 may be 1.2 μm. In this way, by making third metal nitride layer 24 thicker than laminated portion 23, the effect of improving the above-mentioned adhesion resistance, wear resistance, etc. is further enhanced.

[0068] The thickness of metal layer 22 may be, for example, not less than 0.1 μm and less than 0.6 μm. That is, metal layer 22 may be thicker than each of first metal nitride layer 23a and second metal nitride layer 23b, and thinner than stacked portion 23.

[0069] (Method of manufacturing coated tool 1) Next, an example of a manufacturing method of the coated tool 1 will be described. Here, an example of a manufacturing method in the case where the substrate 10 is made of cBN will be described. First, TiN raw material powder of 72 volume % to 82 volume %, Al raw material powder of 13 volume % to 23 volume %, and Al2O3 raw material powder of 1 volume % to 11 volume % are prepared. Then, an organic solvent is added to each of the prepared raw material powders. As the organic solvent, alcohols such as acetone and isopropyl alcohol (IPA) can be used. Then, the mixture is pulverized and mixed in a ball mill for 20 hours to 24 hours. After pulverization and mixing, the solvent is evaporated to obtain a first mixed powder.

[0070] Next, cBN powder having an average particle size of 2.5 μm to 4.5 μm and cBN powder having an average particle size of 0.5 μm to 1.5 μm are mixed in a volume ratio of 8 to 9:1 to 2.0. An organic solvent is then added. As the organic solvent, alcohols such as acetone and IPA can be used. The mixture is then pulverized and mixed in a ball mill for 20 to 24 hours. After pulverization and mixing, the solvent is evaporated to obtain a second mixed powder.

[0071] Next, the obtained first mixed powder and second mixed powder are mixed in a volume ratio of 68 to 78:22 to 32. An organic solvent and an organic binder are added to the mixed powder. As the organic solvent, alcohols such as acetone and IPA can be used. As the organic binder, paraffin, acrylic resin, etc. can be used. Then, the mixture is pulverized and mixed in a ball mill for 20 to 24 hours, and the organic solvent is evaporated to obtain a third mixed powder. In addition, a dispersant may be added in the process using the ball mill as necessary.

[0072] The third mixed powder is then molded into a desired shape to obtain a molded body. For molding, known methods such as uniaxial pressing and cold isostatic pressing (CIP) can be used. The molded body is heated to a desired temperature within a range of 300°C to 600°C to evaporate and remove the organic binder.

[0073] Next, the compact is placed in an ultra-high pressure heating device and heated at 1200°C to 1500°C for 15 minutes to 30 minutes under a pressure of 4 GPa to 6 GPa. This produces a cubic boron nitride sintered body according to the embodiment. The cubic boron nitride sintered body is then attached to the seat of a tip body made of cemented carbide via a bonding material. This produces a tip according to the embodiment.

[0074] Next, a high adhesion layer 20A is formed on the surface of the chip by physical vapor deposition (PVD), and then a low adhesion layer 20B is further formed on the surface of the chip. For example, when the low adhesion layer 20B is made of resin or paint, it can be formed by dip coating or the like. When the low adhesion layer 20B is a CVD film or a PVD film, it can be formed by using the CVD method or the PVD method, respectively. In this way, the coated tool 1 according to the embodiment is obtained.

[0075] <Cutting tools> Next, the configuration of a cutting tool including the above-mentioned coated tool 1 will be described with reference to Fig. 8. Fig. 8 is a front view showing an example of a cutting tool according to an embodiment.

[0076] As shown in FIG. 8, a cutting tool 100 according to the embodiment includes a coated tool 1 and a holder 70 for fixing the coated tool 1.

[0077] The holder 70 is a rod-shaped member extending from a first end (the upper end in FIG. 8) to a second end (the lower end in FIG. 8). The holder 70 is made of, for example, steel or cast iron. Of these materials, it is particularly preferable to use steel, which has high toughness.

[0078] The holder 70 has a pocket 73 at the end on the first end side. The pocket 73 is a portion where the coated tool 1 is attached, and has a seating surface that intersects with the rotation direction of the workpiece and a constraint side surface that is inclined relative to the seating surface. The seating surface is provided with a screw hole into which a screw 75, which will be described later, is screwed.

[0079] The coated tool 1 is positioned in a pocket 73 of the holder 70, and is attached to the holder 70 by a screw 75. That is, the screw 75 is inserted into the through hole 5 of the coated tool 1, and the tip of the screw 75 is inserted into a screw hole formed in the seating surface of the pocket 73 to screw the threaded portions together. In this way, the coated tool 1 is attached to the holder 70 such that the cutting edge portion 3 protrudes outward from the holder 70.

[0080] In the embodiment, a cutting tool used for so-called turning is exemplified. Examples of turning include inner diameter machining, outer diameter machining, and grooving. The cutting tool is not limited to the one used for turning. For example, the coated tool 1 may be used as a cutting tool used for turning.

[0081] For example, cutting of a workpiece includes (1) a step of rotating the workpiece, (2) a step of bringing the cutting edge 11 of the coated tool 1 into contact with the rotating workpiece to cut the workpiece, and (3) a step of removing the coated tool 1 from the workpiece. Representative examples of the material of the workpiece include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0082] <Other embodiments> In the above-described embodiment, a coated tool 1 has been described in which a substrate 10 made of boron nitride particles or the like is attached to a tip body 2 made of cemented carbide or the like, and these are coated with a coating layer 20. However, the coated tool according to the present disclosure may be, for example, a hexahedral substrate whose upper and lower surfaces are parallelogram-shaped, and the entire substrate is made of a cubic boron nitride sintered body, with a coating layer formed on such a substrate.

[0083] In the above embodiment, an example was shown in which the shapes of the upper and lower surfaces of the coated tool 1 are parallelograms, but the shapes of the upper and lower surfaces of the coated tool 1 may be rhombus, square, etc. Also, the shapes of the upper and lower surfaces of the coated tool 1 may be triangle, pentagon, hexagon, etc.

[0084] The shape of the coated tool 1 may be a positive type or a negative type. The positive type is a type in which the side surface is inclined with respect to a central axis passing through the center of the upper surface and the center of the lower surface of the coated tool 1, and the negative type is a type in which the side surface is parallel to the central axis.

[0085] In the above-described embodiment, an example in which the substrate 10 contains particles of cubic boron nitride (cBN) has been described. The substrate disclosed in the present application may contain particles of hexagonal boron nitride (hBN), rhombohedral boron nitride (rBN), wurtzite boron nitride (wBN), or the like. The substrate 10 is not limited to boron nitride, and may be, for example, a cemented carbide or a cermet. The cemented carbide contains W (tungsten), specifically WC (tungsten carbide). The cemented carbide may contain Ni (nickel) or Co (cobalt). The cermet contains, for example, Ti (titanium), specifically TiC (titanium carbide) or TiN (titanium nitride). The cermet may contain Ni or Co.

[0086] In the above embodiment, the coated tool 1 has been described as being used for cutting processing, but the coated tool according to the present application can also be applied to tools other than cutting tools, such as excavation tools and blades.

[0087] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0088] 1: Coated tools 3: Cutting edge 6: 1st page 7:Second side 8: Ridge 9:Third side 10: Base 11: Cutting edge 20: Covering layer 20A: High adhesion layer 20B: Low adhesion layer 21:Hard layer 22: Metal layer 23: Laminated section 23a: first metal nitride layer 23b: second metal nitride layer 24: Third metal nitride layer 30: Substrate 61: Corner 100:Cutting tools 201: 1st coating layer 202:Second coating layer 203:Third coating layer

Claims

1. A substrate; a coating layer overlying the substrate, The coated tool comprises: a first surface having a rake surface; a second surface having a flank surface; a ridge portion located between the first surface and the second surface; having A cutting edge is located on at least a portion of the ridge line portion, The cutting edge has at least a portion having a third surface, The coating layer is a second coating layer located on the second surface; a third coating layer located on the third surface; and having the second coating layer includes a high adhesion layer located on the second surface and a low adhesion layer located on the high adhesion layer, the third coating layer includes the low adhesion layer located on the third surface, The high adhesion layer contains Al and Cr, The high adhesion layer is A hard layer; a metal layer containing Al and Cr located between the substrate and the hard layer; The low adhesion layer is a nitride, carbide, or carbonitride of Ti, When the adhesion between the second coating layer and the second surface is defined as a second adhesion, and the adhesion between the third coating layer and the third surface is defined as a third adhesion, The coated tool, wherein the third adhesion strength is less than the second adhesion strength.

2. The coated tool according to claim 1 , wherein the third adhesion strength is 40 N or less.

3. The coated tool according to claim 1 or 2, wherein the second adhesion strength is 80 N or more.

4. The coating layer includes a first coating layer located on the first surface, When the adhesion between the first coating layer and the first surface is defined as a first adhesion, The coated tool according to claim 1 , wherein the third adhesion is smaller than the first adhesion.

5. The coated tool according to claim 1 , wherein a thickness of the third coating layer is thinner in a region close to the first surface than in a region close to the second surface.

6. The coated tool according to claim 5 , wherein a thickness of the third coating layer gradually increases from the first surface toward the second surface.

7. The coated tool according to any one of claims 1 to 6, wherein the substrate contains cubic boron nitride particles.

8. The coated tool according to any one of claims 1 to 7, wherein the metal layer is an Al-Cr alloy layer containing an Al-Cr alloy.

9. a rod-shaped holder having a pocket at one end; The coated tool according to any one of claims 1 to 8, which is located in the pocket. A cutting tool having

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