Coated tool, cutting tool and manufacturing process of a machined product

Abstract

A coated tool (1) comprising: a base element (3) having a first surface (7) and a coating layer (5) arranged on the first surface (7), wherein the coating layer (5) comprises a first layer (13) arranged on the first surface (7) and containing an aluminum oxide, and a second layer (15) arranged thereon in contact with the first layer (13) and containing a titanium compound, and in a cross-section orthogonal to the first surface (7), the first layer (13) has a first projection (17) projecting towards the second layer (15) and a first recess (19) arranged on the first projection (17), and the second layer (15) has a second recess (21) engaging with the first projection (17) and a second projection (23) engaging with the first recess (19), wherein the first layer (13) comprises a plurality of columnar crystals (13a) which extend individually from one side of the base element (3) towards the second layer (15), and wherein in cross-section orthogonal to the first surface (7) a front end (23a) of the second projection (23) is arranged at a boundary (13b) between the mutually adjacent columnar crystals (13a).

Description

TECHNICAL FIELD

[0001] The present embodiment relates to a coated tool for use in a cutting operation. BACKGROUND

[0002] As a coated tool for use in a cutting process such as a turning process and a milling process, a coated tool is known, which is described, for example, in JP 2009-166216 A. The tool described in JP 2009-166216 A has a configuration in which a coating layer is disposed on a surface of the base member formed of cemented carbide or the like. The coating layer includes a layer (multilayer coating) containing a compound of titanium (Ti) or the like, a layer (bonding layer) containing a compound of titanium, and a layer (α-type alumina layer) containing an α-type alumina (α-Al2O3).

[0003] In the coated tool described in JP 2009 - 166216 A, the surface of the bonding layer has a dendritic shape consisting of tree-like protrusions and branch-like protrusions. It is described that, since the bonding layer has a dendritic shape, the adhesion between the bonding layer and the α-type aluminum oxide layer is improved by an anchoring effect.

[0004] However, the coated tool described in JP 2009-166216 A has a configuration in which both the tree-like protrusion and the branch-like protrusion protrude from the bonding layer toward the α-type alumina layer. In cases where the coating layer has such a configuration, both the load due to the tree-like protrusion and the load due to the branch-like protrusion, which are caused by the anchoring effect, are input to the α-type alumina layer. Therefore, the durability of the coating layer may be reduced.

[0005] Furthermore, from DE 600 37 893 T2 a coated tool is known, comprising: a base element having a first surface, and a coating layer arranged on the first surface, wherein the coating layer comprises a first layer arranged on the first surface and containing an aluminum oxide, and a second layer arranged thereon in contact with the first layer and containing a titanium compound, wherein in a cross section orthogonal to the first surface a maximum roughness at an interface of the first layer and the second layer is large.

[0006] In addition, other coated tools are known from EP 2 497 590 B1 or DE 10 2004 007 653 A1.

[0007] It is an object of the present invention to provide a coated tool for a cutting tool and a manufacturing method of a machined product having increased durability. SUMMARY

[0008] The object is achieved by a coated tool having the features according to claim 1. The object is further achieved by a cutting tool having the features according to claim 7. The object is further achieved by a manufacturing method of a machined product having the features according to claim 8. Further embodiments of the coated tool are described in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing a coated tool in one embodiment. Fig. 2 is a sectional view along the line AA in the coated tool used in the Fig. 1 is shown. Fig. 3 is an enlarged view near a coating layer of the coated tool used in the Fig. 2 is shown. Fig. Figure 4 is an enlarged view of an area B1 shown in the Fig. 3 is shown. Fig. Figure 5 is an enlarged view of an area B2 shown in the Fig. 4 is shown. Fig. 6 is a plan view showing a cutting tool in the embodiment. Fig. Figure 7 is an enlarged view of an area B3 shown in the Fig. 6 is shown. Fig. 8 is a schematic diagram showing a step in a manufacturing process of a machined product in the embodiment. Fig. 9 is a schematic diagram showing a step in a manufacturing process of a machined product in the embodiment. Fig. 10 is a schematic diagram showing a step in a manufacturing process of a machined product in the embodiment. EMBODIMENTS

[0009] A coated tool 1 in the embodiment will be described in detail below with reference to the drawings. For descriptive purposes, the following referenced drawings show, in a simplified form, only major elements necessary for describing the following embodiment. Therefore, the coated tool 1 may include any structural elements not shown in the referenced drawings. Dimensions of these elements in each of the drawings are not those that faithfully represent the dimensions of actual structural elements and dimensional relationships of these elements. Coated tool

[0010] The coated tool 1 of the embodiment comprises a base member 3 and a coating layer 5 as shown in the Fig. 1 and Fig. 2. In the example shown in the Fig. 2, the base element 3 has a first surface 7 (in the Fig. 2 an upper surface), a second surface 9 adjacent to the first surface 7 (in the Fig. 2 a side surface) and a cutting edge 11 which is arranged on at least part of a ridge line at which the first surface 7 intersects the second surface 9.

[0011] In the example shown in the Fig. 1, the base member 3 has a quadrilateral plate shape. The number of second surfaces 9 is therefore four. In the coated tool 1 of the example, at least a part of the first surface 7 is a rake face region, and at least a part of the second surface 9 is a flank region. The shape of the base member 3 is not limited to the quadrilateral plate shape. For example, the first surface 7 may have a triangular, pentagonal, or hexagonal shape. Alternatively, the base member 3 may have a columnar shape in addition to the plate shape.

[0012] The coating layer 5 is arranged on at least the first surface 7 of the base member 3. In the base member 3, the coating layer 5 can be arranged only on the first surface 7 or on a surface other than the first surface 7. In the coated tool 1 of the example, the coating layer 5 is also arranged on the second surface 9 in addition to the first surface 7. The coating layer 5 is provided for the purpose of improving the characteristics of the coated tool 1 during a cutting process, such as wear resistance and chipping resistance.

[0013] In the example shown in the Fig. As shown in Figure 3, the coating layer 5 comprises a first layer 13 and a second layer 15. The first layer 13 is disposed on the first surface 7 and contains an aluminum oxide (Al2O3). The second layer 15 is disposed thereon in contact with the first layer 13 and comprises a titanium compound.

[0014] The first layer 13 may comprise aluminum oxide as a main component. The second layer 15 may comprise a titanium compound as a main component. The term "main component" refers to a component that has the highest value in weight percent among the other components.

[0015] The first layer 13 may contain a component other than aluminum oxide, and the second layer 15 may contain a component other than the titanium compound. For example, the bondability between the first layer 13 and the second layer 15 is improved when the first layer 13 contains the titanium compound. Furthermore, the bondability between the first layer 13 and the second layer 15 is also improved when the second layer 15 contains aluminum oxide.

[0016] Examples of the alumina in the first layer 13 include α-alumina (α-Al2O3), γ-alumina (γ-Al2O3), and κ-alumina (κ-Al2O3). When the first layer contains the largest amount of α-alumina among these, the heat resistance of the coated tool 1 is high. The first layer 13 may contain only one of the above compounds, or alternatively, it may contain a plurality of the above compounds.

[0017] Identification of the aluminum oxide contained among the above compounds in the first layer 13 can be evaluated, for example, by performing X-ray diffraction (XRD) analysis or by matching with the JCPDS database.

[0018] The α-alumina, the γ-alumina and the κ-alumina may be contained in the first layer 13 in any state, for example, they may be contained in the first layer 13 in a state of a plurality of columnar crystals 13a individually extending from one side of the base member 3 toward the second layer 15.

[0019] Examples of the titanium compound contained in the second layer 15 include titanium carbide, nitride, oxide, carbonitride, carbon oxide, and oxycarbonitride. The second layer 15 may be configured to contain only one of the above compounds, or may alternatively be configured to contain a plurality of the above compounds.

[0020] A boundary between the first layer 13 and the second layer 15 can be determined, for example, by observing a scanning electron microscope (SEM) image or a transmission electron microscope (TEM) image.

[0021] When the coating layer 5 is viewed in a cross-section orthogonal to the first surface 7, the first layer 13 has a first protrusion 17 and a first recess 19 at an interface on the side that will be connected to the second layer 15 (an interface on the upper side of the Fig. 4), at which the first projection 17 projects towards the second layer 15, and in the example shown in the Fig. 4, the first recess 19 is arranged on the first projection 17. The second layer 15 has a second recess 21 and a second projection 23 at an interface on the side which is connected to the first layer 13 (an interface on the lower side of the Fig. 4), at which the second recess 21 engages with the first projection 17 and the second projection 23 engages with the first recess 19.

[0022] In the coating layer 5 in the example shown in the Fig. 4 and Fig. As shown in Figure 5, the first protrusion 17 protrudes toward the second layer 15, and the second protrusion 23 protrudes toward the first layer 13. Therefore, due to the anchor effect, the first protrusion 17 has a strong connection capability with the second layer 15, and the second protrusion 23 has a strong connection capability with the first layer 13.

[0023] Since the first layer 13 has the first protrusion 17 and the second layer 15 has the second protrusion 23, the load caused by the anchoring effect is hardly unbalanced for only one of the first layer 13 and the second layer 15. Therefore, the coated tool 1 provided with the coating layer 5 has strong bonding ability due to the anchoring effect and high durability.

[0024] The sizes of the first protrusion 17 and the second protrusion 23 are not limited to specific numerical values. For example, in the cross-section orthogonal to the first surface 7, where Rz is a maximum height of the intersection of the first surface 7 located on the second surface 9 side, the height of the first protrusion 17 may be set to be equal to or more than Rz / 10, and the height of the second protrusion 23 may be set to be less than Rz / 10.

[0025] In the following description, when viewed in cross section, as shown in the Fig. 5, the length of a first virtual straight line connecting a pair of base ends of the protrusion is defined as a width W. The length of a second virtual straight line orthogonal to the first virtual straight line and passing through the first virtual straight line and the top of the protrusion is defined as a height H of the protrusion.

[0026] Since the second protrusion 23 engages with the first recess 19 and the first recess 19 is arranged on the first protrusion 17, the first protrusion 17 is larger than the second protrusion 23 in the coated tool 1 of the example. Specifically, a width W1 of the first protrusion 17 is larger than a width W2 of the second protrusion 23, and a height H1 of the first protrusion 17 is larger than a height H2 of the second protrusion 23. For this reason, the durability of the coated tool 1 is high.

[0027] Since the first protrusion 17 is larger than the second protrusion 23, the load due to the anchoring effect is applied more to the second recess 21 than to the first recess 19. At this time, the second layer 15 is arranged on the first layer 13 in contact with it. Therefore, even if a crack occurs in the second recess 21 in a direction away from the first layer 13 caused by a load due to the anchoring effect, this load can be released at the surface of the coating layer 5.

[0028] On the other hand, since the load caused by the anchoring effect acting on the first recess 19 is relatively small, the crack is less likely to occur in the first recess 19 in a direction away from the second layer 15, in other words, in a direction toward the inside of the coated tool 1. As described above, since the crack hardly advances in depth, the durability of the coated tool 1 is high.

[0029] The coating layer 5 is not limited to the configuration having only the first layer 13 and the second layer 15, and may have a layer in addition to the first layer 13 and the second layer 15. For example, as shown in Fig. 3, the coating layer 5 may comprise a third layer 25 disposed between the base member 3 and the first layer 13 in addition to the first layer 13 and the second layer 15.

[0030] The third layer 25 comprises a titanium compound in the example shown in the Fig. 3. Examples of the titanium compound contained in the third layer 25 include, as in the second layer 15, titanium carbide, nitride, oxide, carbonitride, carbon oxide, and oxycarbonitride.

[0031] The third layer 25 may be formed as a single layer or, alternatively, may have a configuration in which a plurality of layers are laminated one upon another. For example, the third layer 25 may have a configuration in which a layer 25b, which is disposed on one side of the base member 3 and contains titanium nitride (TiN), and a layer 25a, which is disposed on one side of the first layer 13 and contains titanium carbonitride (TiCN), are arranged in sequence.

[0032] In a case where the third layer 25 includes the layer 25b containing titanium nitride, the bonding ability of the base member 3 and the coating layer 5 is high. In a case where the third layer 25 includes the layer 25a containing titanium carbonitride, the bonding ability between the third layer 25 and the first layer 13 is high.

[0033] An analysis of the components contained in each of the first layer 13, the second layer 15, and the third layer 25 can be evaluated, for example, by SEM-EDX using an energy dispersive X-ray spectrometer (EDX) attached to a scanning electron microscope or by a method using an electron beam microanalysis apparatus (EPMA).

[0034] In the cross section orthogonal to the first surface 7, the number of first protrusions 17 and second protrusions 23 in the first layer 13 is not particularly limited, and each of them may be one or a plurality. In the cross section described above, when the first layer 13 has a plurality of first protrusions 17, the connection capability is high due to the anchor effect.

[0035] Moreover, in the cross section orthogonal to the first surface 7, when a plurality of first recesses 19 are arranged on a first projection 17, the connectability between the first layer 13 and the second layer 15 is further high and the durability of the first layer 13 and the second layer 15 is further high.

[0036] Since the first protrusion 17 is larger than the second protrusion 23, the anchoring effect by one of the first protrusion 17 is larger than the anchoring effect by one of the second protrusion 23. At this time, when the plurality of first recesses 19 are arranged on a first protrusion 17, the anchoring effect by one of the second protrusion 23 with respect to the first protrusion 17 is large. Therefore, the bondability between the first layer 13 and the second layer 15 is further high, and the durability of the first layer 13 and the second layer 15 is further high.

[0037] In the cross section orthogonal to the first surface 7, the direction in which the first projection 17 and the second projection 13 project is not limited to a specific direction. As shown in the example shown in the Fig. As shown in Figure 4, when the direction in which the second protrusion 23 protrudes is inclined relative to the direction in which the first protrusion 17 protrudes, the load due to the anchoring effect in the first protrusion 17 and the load due to the anchoring effect in the second protrusion 23 are easily distributed. Therefore, the durability of the coating layer 5 is high.

[0038] The direction in which the first protrusion 17 protrudes is a protrusion direction, which is defined as the direction in which the line connecting the midpoint of the straight line connecting the two base ends 17b and a front end 17a extends. Similarly, the direction in which the second protrusion 23 protrudes is a protrusion direction, which is defined as the direction in which the line connecting the midpoint of the straight line connecting the two base ends 23b and a front end 23a extends.

[0039] In cross section orthogonal to the first surface 7, when the plurality of first recesses 19 are arranged on one of the first projections 17, as in the example of Fig. 4, at least one of the plurality of first recesses 19 may be recessed in a direction away from the base member 3. In other words, at least one of the plurality of second protrusions 23 may protrude in the direction away from the base member 3. When the second protrusion 23 protrudes in the above direction, even if a crack occurs in the first recess 19 caused by a load due to the anchor effect, it is easy to prevent the crack from advancing toward the base member 3.

[0040] As in the example shown in the Fig. 4 and Fig. 5, the first layer 13 may comprise the plurality of columnar crystals 13a. In the cross section orthogonal to the first surface 7, the base end 17b of the first projection 17 may be arranged at a boundary 13b between the adjacent columnar crystals 13a, as shown in FIG. Fig. 5. A relatively large load is likely to be applied to the base end 17b of the first protrusion 17. However, if the base end 17b of the first protrusion 17 is positioned at the described location, the crack is less likely to propagate from the base end 17b of this first protrusion 17 toward the interior of the columnar crystal 13a. Therefore, the durability of the first layer 13 is high.

[0041] In the cross section orthogonal to the first surface 7, the front end 23a of at least one of the second protrusions 23 may be located at the boundary 13b between the adjacent columnar crystals 13a. A relatively large load is likely to be applied to the bottom of the first recesses 19, which engages with the front end 23a of the second protrusion 23. However, if the front end 23a of the second protrusion 23 is located at the above-described location, the crack is less likely to propagate from the bottom of the first recess 19 toward the interior of the columnar crystal 13a. Therefore, the durability of the first layer 13 is high.

[0042] As in the example shown in the Fig. 5, the direction in which the second projection 23 extends may be inclined relative to the direction in which the columnar crystal 13a extends (vertical direction in the Fig. 5). When the second protrusion 23 protrudes as described above, the direction in which the first recess 19 engaging with the second protrusion 23 is recessed is inclined relative to the direction in which the columnar crystal 13a extends. In such a case, since the direction in which the load applied from the second protrusion 23 to the first recess 19 is inclined relative to the direction in which the columnar crystal 13a extends, the crack is less likely to occur at the boundary 13b between the adjacent columnar crystals 13a.

[0043] Examples of the material of the base member 3 include inorganic materials such as cemented carbide, cermet, and ceramics. The material of the base member is not limited to these materials.

[0044] Examples of cemented carbide compositions include WC-(tungsten carbide)-Co, WC-TiC-(titanium carbide)-Co, and WC-TiC-TaC-(tantalum carbide)-Co. Specifically, WC, TiC, and TaC are hard particles, and Co is a binder phase. Cermet is a sintered composite material obtained by combining metal and a ceramic component. Specific examples of cermets include compounds composed primarily of TiCN, TiC, or TiN.

[0045] The base element 3 may have a through hole 27 which passes through the first surface 7 and a surface (the lower surface in the Fig. 1), which is arranged on an opposite side of the first surface 7. The through-hole 27 is usable for receiving a fixing element that fixes the coated tool 1 to the holder. Examples of the fixing element include a screw and a clamping element.

[0046] The size of the base member 3 is not particularly limited. For example, a length of one side of the first surface 7 may be set to approximately 3 to 20 mm. A height from the first surface 7 to the surface located on the opposite side of the first surface 7 may be set to approximately 5 to 20 mm. Manufacturing process

[0047] A method for manufacturing the coated tool 1 in the embodiment is described below.

[0048] First, a powder mixture is prepared by appropriately adding metal powder, carbon powder, or the like to an inorganic powder selected from carbide, nitride, carbonitride, and oxide or the like capable of forming a hard alloy by sintering, which forms the base member 3, and then mixing them together. Subsequently, a molded article is manufactured by molding the powder mixture into a predetermined die shape using a known molding method. Examples of the molding method include press molding, casting molding, extrusion molding, and cold isostatic pressing. The base member 3 is manufactured by sintering the molded article in a vacuum or a non-oxidizing atmosphere. A surface of the base member may then be subjected to polishing and honing, if necessary.

[0049] Subsequently, the coating layer 5 is deposited on the surface of the base element 3 by a chemical vapor deposition (CVD) process.

[0050] The first layer 13 can be formed by the following method. A first gas mixture is prepared by mixing 5 to 15 vol% of aluminum trichloride (AlCl3) gas, 0.5 to 2.5 vol% of hydrogen chloride (HCl) gas, 0.5 to 5.0 vol% of carbon dioxide (CO2) gas, and equal to or less than 1 vol% of hydrogen sulfide (H2S) gas in hydrogen (H2) gas. This first gas mixture is introduced into the chamber under conditions of a deposition temperature of 950 to 1100°C and a gas pressure of 5 to 20 kPa. In this way, the first layer 13 can be formed in the coating layer 5.

[0051] The second layer 15 can be formed by the following method. A second gas mixture is prepared by mixing 0.1 to 10 vol% titanium tetrachloride (TiCl4) gas and 10 to 60 vol% nitrogen (N2) gas in hydrogen gas. This second gas mixture is introduced into the chamber under conditions of a deposition temperature of 960 to 1100 °C and a gas pressure of 10 to 85 kPa. In this way, the second layer 15 can be formed in the coating layer 5.

[0052] At this time, instead of continuously forming the second layer 15 after forming the first layer 13, the base member 3 covered with the first layer 13 is removed from the chamber, and the surface of the first layer 13 is machined. Therefore, the first layer 13 having the first protrusion 17 and the first recess 19 can be formed. The surface processing described above is not limited to a specific processing, but includes shot blasting, laser processing, and etching.

[0053] Specifically, for example, when the first layer 13 is formed using the first gas mixture, the first protrusion 17 is formed, and blasting is performed by blasting particles having a particle diameter smaller than the height of the first protrusion 17 onto the surface of the first layer 13 having the first protrusion 17, whereby the first recess 19 can be formed.

[0054] When the coating layer 5 has the third layer 25 disposed between the base member 3 and the first layer 13, the third layer 25 can be formed using the following method.

[0055] First, a third gas mixture is prepared by mixing 0.5 to 10 vol% titanium tetrachloride gas and 10 to 60 vol% nitrogen gas in hydrogen gas. This third gas mixture is introduced into the chamber under conditions of a deposition temperature of 800 to 940 °C and a gas pressure of 8 to 50 kPa. In this way, the layer 25b containing titanium nitride can be formed in the third layer 25.

[0056] A fourth gas mixture is prepared by mixing 0.5 to 10 vol% titanium tetrachloride gas, 5 to 60 vol% nitrogen gas, and 0.1 to 3 vol% acetonitrile (CH3CN) gas in hydrogen gas. This fourth gas mixture is introduced into the chamber under conditions of a deposition temperature of 780 to 880 °C and a gas pressure of 5 to 25 kPa. In this way, the layer 25a containing titanium carbonitride can be formed in the third layer 25.

[0057] Subsequently, if necessary, a polishing process is performed on a portion of the surface of the deposited coating layer 5 where the cutting edge 11 is located. When the polishing process is performed, a workpiece is less likely to weld to the cutting edge 11, resulting in the coated tool 1 having excellent fracture resistance.

[0058] The above manufacturing method is an example of the method for manufacturing the coated tool 1 of the embodiment. Therefore, the coated tools 1 are not limited to those manufactured by the above manufacturing method. Cutting tool

[0059] A cutting tool 101 of the embodiment will be described below with reference to the drawings.

[0060] In the Fig. 6 and Fig. In the example shown in Figure 7, the cutting tool 101 has a rod-shaped main body which extends from a first end (an upper end in the Fig. 6) extends to a second end (a lower end in the Fig. 6). The cutting tool 101 has a holder 105 with a pocket 103 arranged on one side of the first end, and the coated tool 1 is arranged in the pocket 103. In the cutting tool 101 of the example shown in the Fig. 6 and Fig. 7, the coated tool 1 is fixed so that a part of a ridge line usable as a cutting edge protrudes from a front end of the holder 105.

[0061] The pocket 103 is a part that allows the coated tool 1 to be secured. The pocket 103 has a seating surface parallel to a lower surface of the holder 105 and a retaining side surface that is inclined relative to the seating surface. The pocket 103 is open in one side of the first end of the holder 105.

[0062] The coated tool 1 is arranged in the pocket 103. A surface on the opposite side of the first surface in the coated tool 1 can be in direct contact with the pocket 103. Alternatively, a plate can be held between the coated tool 1 and the pocket 103.

[0063] The coated tool 1 is mounted so that the part of the ridge line usable as the cutting edge protrudes outward from the holder 105. In the example shown in the Fig. 6 and Fig. 7, the coated tool 1 is fixed to the holder 105 by a screw 107. Specifically, the coated tool 1 is fixed to the holder 105 in such a manner that screw parts are engaged with each other by inserting the screw 107 into the through hole of the coated tool 1 and by inserting a front end of the screw 107 into a screw hole (not shown) formed in the pocket 103.

[0064] For example, steel and cast iron can be used as the holder 105. When steel is used among these members, the toughness of the holder is high.

[0065] The embodiment has described and illustrated cutting tools for use in a so-called turning process. Examples of the turning process include inner diameter machining, outer diameter machining, and grooving machining. The cutting tools are not limited to those used in the turning process. For example, the coated tools 1 of the above embodiments are applicable to cutting tools for use in the milling process. Manufacturing process of a machined product

[0066] A manufacturing method of a machined product in the embodiment will be described below with reference to the drawings.

[0067] The machined product can be manufactured by performing a cutting process of a workpiece 201. The method for manufacturing a machined product in the embodiment comprises the following steps: (1) Rotating the workpiece 201, (2) Bringing the cutting tool 101 represented by the above embodiment into contact with the workpiece 201 which is rotated, and (3) Moving the cutting tool 101 away from the workpiece 201.

[0068] In particular, the workpiece 201 is first rotated about an axis O2 and then the cutting tool 101 is brought relatively close to the workpiece 201, as shown in the Fig. 8. Then, the workpiece 201 is cut by bringing the cutting edge in the cutting tool 101 into contact with the workpiece 201, as shown in the Fig. 9. Thereafter, the cutting tool 101 is moved relatively away from the workpiece 201, as shown in the Fig. 10 is shown.

[0069] In the Fig. 8, the cutting tool 101 is brought close to the workpiece 201 by fixing the axis O2 and moving the cutting tool 101 in a Y1 direction in a state in which the workpiece 201 is rotated around the axis O2. In the example shown in Fig. 9, the workpiece 201 is cut by bringing the cutting edge in an insert 1 into contact with the workpiece 201, which is rotated. In the example shown in the Fig. 10, the cutting tool is moved away by moving in the Y2 direction in a state in which the workpiece 201 is rotated.

[0070] During the cutting process in the manufacturing method of the embodiment, the cutting tool 101 is brought into contact with the workpiece 201 or the cutting tool 101 is moved away from the workpiece 201 by moving the cutting tool 101 in each of the steps. However, it is not intended to be limited to the above embodiment.

[0071] For example, in step (1), the workpiece 201 may be brought close to the cutting tool 101. Similarly, in step (3), the workpiece 201 may be moved away from the cutting tool 101. As the cutting operation continues, it is necessary to repeat the step of bringing the cutting edge of the insert 1 into contact with various portions of the workpiece 201 while continuing to rotate the workpiece.

[0072] Representative examples of the material of the workpiece 201 include unalloyed steel, alloy steel, stainless steel, cast iron, and non-ferrous metals. LIST OF REFERENCE SYMBOLS 1 coated tool 3 Basic element 5 coating layer 7 first area 9 second area 11 Cutting edge 13 first layer 13a Columnar crystal 13b Boundary between adjacent columnar crystals 15 second layer 17 first lead 17a front end 17b Base end 19 first recess 21 second recess 23 second lead 23a front end 23b Base end 25 third layer 25a Layer on one side of the first layer 25b Layer on one side of the base element 27 through hole 101 Cutting tools 103 Bag 105 holders 107 Fixing screw 201 Workpiece H1 Height of the first projection H2 Height of the second projection W1 Width of the first projection W2 Width of the second projection Y1 Direction of movement of the cutting tool Y2 Direction of movement of the cutting tool O2 Rotation axis of the workpiece

Claims

[1] A coated tool (1) comprising: a base element (3) having a first surface (7) and a coating layer (5) arranged on the first surface (7), wherein the coating layer (5) comprises a first layer (13) arranged on the first surface (7) and containing an aluminum oxide, and a second layer (15) arranged thereon in contact with the first layer (13) and containing a titanium compound, and in a cross-section orthogonal to the first surface (7), the first layer (13) has a first projection (17) projecting towards the second layer (15) and a first recess (19) arranged on the first projection (17), and the second layer (15) has a second recess (21) engaging with the first projection (17) and a second projection (23) engaging with the first recess (19), wherein the first layer (13) comprises a plurality of columnar crystals (13a) which extend individually from one side of the base element (3) towards the second layer (15), and wherein in cross-section orthogonal to the first surface (7) a front end (23a) of the second projection (23) is arranged at a boundary (13b) between the mutually adjacent columnar crystals (13a). [2] The coated tool (1) according to claim 1, wherein a plurality of first recesses (19) are arranged on a first projection (17) in cross-section orthogonal to the first surface (7). [3] The coated tool (1) according to claim 1 or 2, wherein in the cross section orthogonal to the first surface (7), a direction in which the second projection (23) projects is inclined relative to a direction in which the first projection (17) projects. [4] The coated tool (1) according to claim 3, wherein in cross-section orthogonal to the first surface (7), a plurality of first recesses (19) are arranged on a first projection (17) and at least one of the plurality of first recesses (19) is recessed in a direction away from the base element (3). [5] The coated tool (1) according to any one of claims 1 to 4, wherein in cross section orthogonal to the first surface (7), a base element of the first projection (17) is arranged at the boundary (13b) between the mutually adjacent columnar crystals (13a). [6] The coated tool (1) according to claim 1, wherein a direction in which the second projection (23) whose front end (23a) is located at the boundary (13b) between the columnar crystals (13a) adjacent to each other is inclined relative to a direction in which the columnar crystals (13a) extend. [7] A cutting tool (101) comprising: a holder (105) having a pocket (103) arranged on one side of a front end of the holder (105), and the coated tool (1) according to any one of claims 1 to 6, which is arranged on the pocket (103). [8] A manufacturing method of a machined product, comprising: Rotating the cutting tool (101) according to claim 7, Bringing the cutting tool (101), which is rotated, into contact with a workpiece (201), and Moving the cutting tool (101) away from the workpiece (201).

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