JP7634575B2 - Coated and cutting tools - Google Patents

Description

The present disclosure relates to coated tools and cutting tools.

Coated tools are known as tools used in cutting processes such as turning and milling, and have improved wear resistance, etc. by coating the surface of a base material such as cemented carbide, cermet, or ceramic with a coating layer (see Patent Document 1).

JP 2002-3284 A

A coated tool according to one aspect 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 on at least a portion 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 the second adhesion force and the adhesion between the third coating layer and the third surface is defined as the third adhesion force, the third adhesion force is smaller than the second adhesion force.

A cutting tool according to one aspect of the present disclosure has a rod-shaped holder having a pocket at an end and the above-mentioned coated tool positioned within the pocket.

FIG. 1 is a perspective view showing an example of a coated tool according to an embodiment. FIG. 2 is a side cross-sectional view showing an example of a coated tool according to an embodiment. FIG. 3 is a schematic enlarged view of part III shown in FIG. FIG. 4 is a schematic cross-sectional view showing another example of the configuration of the coating layer. FIG. 5 is a schematic cross-sectional view showing another example of the configuration of the coating layer. FIG. 6 is a schematic enlarged view of portion VI shown in FIG. FIG. 7 is a schematic enlarged view of portion VII shown in FIG. FIG. 8 is a front view illustrating an example of a cutting tool according to an embodiment.

Below, the form for implementing the coated tool and cutting tool according to the present disclosure (hereinafter, referred to as "embodiment") will be described in detail with reference to the drawings. Note that the coated tool and cutting tool according to the present disclosure are not limited to this embodiment. Furthermore, each embodiment can be appropriately combined to the extent that the processing content is not contradictory. Furthermore, the same parts in each of the following embodiments are given the same reference numerals, and duplicate explanations will be omitted.

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," or "parallel" in the strict sense. In other words, each of the above expressions allows for deviations due to, for example, manufacturing precision, installation precision, and the like.

There are known coated tools that have improved wear resistance and other properties by coating the surface of a substrate such as cemented carbide, cermet, or ceramic with a coating layer. However, there is room for further improvement in this type of coated tool in terms of achieving a longer life.

<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.

The coated tool 1 has a first surface 6 (here, the top surface), a second surface 7 (here, the 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 that scoops up chips generated by cutting. In addition, the second surface 7 has a relief surface.

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

(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.

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 portion 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).

(Cutting edge portion 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.

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.

(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, Al ₂ O ₃ , etc. 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.

At least a part of the cutting edge 11 is provided with a third surface 9 that is continuous with the first surface 6 and the second surface 7. The third surface 9 is, for example, a C surface (chamfered surface) in which the corner between the first surface 6 and the second surface 7 is cut obliquely and linearly. The third surface 9 may also be an R surface (rounded surface) in which the corner between the first surface 6 and the second surface 7 is rounded.

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

(Covering 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.

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. Here, if the adhesion between the first coating layer and the first surface 6 is the first adhesion force, the adhesion between the second coating layer and the second surface 7 is the second adhesion force, and the adhesion between the third coating layer and the third surface 9 is the third adhesion force, in the coated tool 1 according to the embodiment, the third adhesion force is smaller than the second adhesion force.

The inventors of the present application have discovered that by relatively reducing the adhesion of the third coating layer located on the third surface 9, it is possible to extend the life of the coated tool 1. One reason for this is thought to be 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 whole of the base material, the substrate 10, is damaged when the third coating layer is destroyed.

Therefore, in the coated tool 1 according to the embodiment, the third adhesion force is made smaller than the first adhesion force and the second adhesion force. The coated tool 1 having such a configuration can suppress damage to the base body 10 at the third surface 9. Therefore, the coated tool 1 according to the embodiment can achieve a longer life.

In addition, since the third coating layer has a relatively small adhesion, it is removed from the third surface 9 when the coated tool 1 is first used (for example, at the first use) 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 whether the third coating layer is present. 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.

The third adhesion force may be 40 N or less. With 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.

The second adhesion force may be 80 N or more. With this configuration, the wear resistance and heat resistance of the second surface 7 can be appropriately increased.

The first adhesion strength to the third adhesion strength may be measured, for example, by a scratch test.

The thickness of the third coating layer may be thinner than the thicknesses of the first coating layer and the second coating layer. By making the third coating layer thinner, damage to the entire base body 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.

(Configuration of Covering Layer 20)
In the embodiment, the coating 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. It is sufficient that the low adhesion layer 20B is located at least on the third surface 9.

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

The low adhesion layer 20B is a film that has a lower 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.

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 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 substrate 10 according to the embodiment and has low adhesion to the substrate 10. For this reason, by using Ti as the low adhesion layer 20B, a low adhesion layer 20B having a lower adhesion than the high adhesion layer 20A can be obtained. 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 substrate 10 is large and the residual stress is large, so that the adhesion can be reduced.

Next, the configuration of the first coating layer to the third coating layer in the coating layer 20 will be described with reference to Figure 3. Figure 3 is a schematic enlarged view of part III shown in Figure 2.

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.

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. 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.

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.

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.

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, similar to the third coating layer 203. In this case, the adhesion between the third coating layer 203 and the third surface 9 (third adhesion) may be equal to the adhesion between the first coating layer 201 and the first surface 6 (first adhesion). In this way, the adhesion between the third coating layer 203 and the third surface 9 (third adhesion) only needs to be smaller than the adhesion between the second coating layer 202 and the second surface 7 (second adhesion).

5, the first surface 6 does not necessarily have to have both the high adhesion layer 20A and the low adhesion layer 20B. In other words, the substrate 10 may be exposed on the first surface 6.

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, compared to when the coating layer 20 is provided on the first surface 6, which corresponds to the rake face. As a result, the coated tool 1 in which the first surface 6, which corresponds to the rake face, is exposed has high durability.

The thickness of the third coating layer 203 may be thinner in the region closer to the first surface 6 than in the 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. A coated tool 1 having such a configuration has a good balance of chipping resistance, wear resistance, and heat resistance.

(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.

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, multiple metal nitride layers may be overlapped. Alternatively, the hard layer 21 may have a laminated portion 23 in which multiple 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.

(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 surface and contacts the hard layer 21 on the other surface.

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.

Note that elemental Ti, elemental Zr, elemental V, elemental Cr, and elemental 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, elemental Hf, elemental Nb, elemental Ta, and elemental 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.

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 adhesion between the substrate 10 and the high adhesion layer 20A.

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.

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 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 95 atomic % or more of Al and Cr in total. Furthermore, the metal layer 22 may contain at least 98 atomic % or more of Al and Cr in total. The proportion of the metal components in the metal layer 22 can be determined, for example, by analysis using EDS (energy dispersive X-ray spectrometry).

In addition, since Ti has poor wettability with the substrate 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 substrate 10. Specifically, the Ti content in the metal layer 22 may be 15 atomic % or less.

In this way, 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. In addition, 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.

In addition, the cBN used as the substrate 10 is an insulator. As an insulator, there is room for improvement in the adhesion of cBN to a film formed by PVD (physical vapor deposition). 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, the adhesion between the hard layer 21 formed by PVD and the metal layer 22 is high.

(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.

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

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.

The thickness of the first metal nitride layer 23a and the second metal nitride layer 23b may each 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.

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.

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

For example, suppose that metal layer 22 contains two types of metals (here, "first metal" and "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. Furthermore, second metal nitride layer 23b contains nitrides of the first metal and a second metal.

For example, in an 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.

In this way, 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.

The first metal nitride layer 23a, i.e., the AlTiN layer, has excellent adhesion to the metal layer 22, as described above, and also has excellent 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 contains the first metal nitride layer 23a and the second metal nitride layer 23b of different compositions, and thus the wear resistance, heat resistance, and other properties of the hard layer 21 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.

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.

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 (AlTiN layer) containing Ti and Al, similar to the first metal nitride layer 23a.

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.

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.

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

The thickness of the metal layer 22 may be, for example, 0.1 μm or more and less than 0.6 μm. That is, the metal layer 22 may be thicker than each of the first metal nitride layer 23a and the second metal nitride layer 23b, and thinner than the laminate portion 23.

(Method of manufacturing the 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 base body 10 is made of cBN will be described. First, TiN raw material powder of 72 vol% to 82 vol%, Al raw material powder _of 13 vol% to 23 vol%, and _Al2O3 raw material powder of 1 vol% to 11 vol% 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.

Next, cBN powder with an average particle size of 2.5 μm to 4.5 μm and cBN powder with 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.

Next, the first mixed powder and the 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. After that, the mixture is pulverized and mixed in a ball mill for 20 to 24 hours, and then the organic solvent is evaporated to obtain a third mixed powder. In addition, a dispersant may be added as necessary in the process using the ball mill.

Then, the third mixed powder is molded into a predetermined shape to obtain a molded body. Known methods such as uniaxial pressing and cold isostatic pressing (CIP) can be used for molding. The molded body is heated to a predetermined temperature in the range of 300°C to 600°C to evaporate and remove the organic binder.

Next, the molded body 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 resulting 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 the tip according to the embodiment.

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, if the low adhesion layer 20B is made of resin or paint, it can be formed by dip coating or the like. Also, if the low adhesion layer 20B is a CVD film or a PVD film, it can be formed using the CVD method or the PVD method, respectively. This results in a coated tool 1 according to the embodiment.

<Cutting tools>
Next, a 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.

As shown in FIG. 8, the cutting tool 100 of the embodiment has a coated tool 1 and a holder 70 for fixing the coated tool 1.

The holder 70 is a rod-shaped member extending from a first end (upper end in FIG. 8) to a second end (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.

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

The coated tool 1 is located in the 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. As a result, the coated tool 1 is attached to the holder 70 so that the cutting edge portion 3 protrudes outward from the holder 70.

In the embodiment, a cutting tool used for so-called turning is exemplified. Examples of turning include internal diameter machining, external diameter machining, and grooving. Note that cutting tools are not limited to those used for turning. For example, the coated tool 1 may be used as a cutting tool used for milling.

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.

<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 one in which, for example, a hexahedral substrate whose upper and lower surfaces are parallelogram-shaped is entirely made of a cubic boron nitride sintered body, and a coating layer is formed on such a substrate.

In the above embodiment, an example is shown in which the shape of the upper and lower surfaces of the coated tool 1 is a parallelogram, but the shape of the upper and lower surfaces of the coated tool 1 may be a rhombus, a square, etc. Also, the shape of the upper and lower surfaces of the coated tool 1 may be a triangle, a pentagon, a hexagon, etc.

The shape of the coated tool 1 may be either 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.

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), etc., without being limited thereto. 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.

In the above-described embodiment, the coated tool 1 is described as being used for cutting processing, but the coated tool according to the present application can also be used for tools other than cutting tools, such as drilling tools and blades.

Further advantages and modifications may readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Thus, 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.

1 : Covered tool 3 : Cutting blade part 6 : First surface 7 : Second surface 8 : Ridge part 9 : Third surface 10 : Base body 11 : Cutting blade 20 : Covering layer 20A : High adhesion layer 20B : Low adhesion layer 21 : Hard layer 22 : Metal layer 23 : Laminated part 23a : First metal nitride layer 23b : Second metal nitride layer 24 : Third metal nitride layer 30 : Substrate 61 : Corner 100 : Cutting tool 201 : First coating layer 202 : Second coating layer 203 : Third coating layer

Claims (9)

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,
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;
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. The coated tool according to claim 1, wherein the third adhesion force is 40 N or less. The coated tool according to claim 1 or 2, wherein the second adhesion force is 80 N or more. 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. The coated tool according to any one of claims 1 to 4, wherein the thickness of the third coating layer is thinner in the region close to the first surface than in the region close to the second surface. The coated tool according to claim 5, wherein the thickness of the third coating layer gradually increases from the first surface to the second surface. The coated tool according to any one of claims 1 to 6, wherein the substrate contains cubic boron nitride particles. 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. a rod-shaped holder having a pocket at one end;
A cutting tool comprising: the coated tool according to any one of claims 1 to 8 located in the pocket.

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