Sintered object, insert, cutting tool, and method for manufacturing cut workpiece

Abstract

In the present invention, a sintered objected comprises a sintered object body having an outer region and an inner region surrounded by the outer region. The inner region includes a plurality of first layers and a plurality of second layers alternately laminated with the plurality of first layers. Each of the plurality of first layers includes a plurality of first hard members arranged side by side in a first direction and containing a first inorganic material. Each of the plurality of second layers includes a plurality of second hard members arranged side by side in a second direction intersecting the first direction and containing a second inorganic material.

Description

Methods for manufacturing sintered bodies, inserts, cutting tools, and machined products

[0001] The disclosed embodiments relate to methods of manufacturing sintered bodies, inserts, cutting tools, and machined products.

[0002] Known methods for producing sintered bodies using inorganic materials such as ceramic powder or metal powder include, for example, a process for producing a metal or ceramic product, which process includes the steps of mixing the ceramic powder or metal powder into a binder to form a compound, sequentially injecting the compound from a nozzle while moving relative to a reference surface, depositing and solidifying the compound to form a three-dimensional object, degreasing the three-dimensional object, and sintering the degreasing three-dimensional object (see, for example, JP 2000-144205 A).

[0003] A sintered body according to one aspect of the embodiment comprises a sintered body body having an outer region and an inner region surrounded by the outer region, the inner region including a plurality of first layers and a plurality of second layers alternately stacked with the plurality of first layers, each of the plurality of first layers including a plurality of first hard members arranged in a first direction and containing a first inorganic material, and each of the plurality of second layers including a plurality of second hard members arranged in a second direction intersecting the first direction and containing a second inorganic material.

[0004] FIG. 1 is a plan view showing an example of a sintered body according to an embodiment. FIG. 2A is a cross-sectional view showing an example of a cross section of a sintered body taken along line A-A' shown in FIG. 1. FIG. 2B is a cross-sectional view showing an example of a cross section of a sintered body taken along line B-B' shown in FIG. 1. FIG. 3A is an enlarged view showing an example of a region R1 shown in FIG. 2B. FIG. 3B is an enlarged view showing an example of a region R2 shown in FIG. 2A. FIG. 4A is a front view showing an example of an outer region of a sintered body according to an embodiment in the Y direction shown in FIG. 1. FIG. 4B is a front view showing an example of an outer region of a sintered body according to an embodiment in the X direction shown in FIG. 1. FIG. 5A is a schematic diagram illustrating an example of a method for manufacturing a sintered body according to an embodiment. FIG. 5B is a schematic diagram illustrating an example of a method for manufacturing a sintered body according to an embodiment. FIG. 5C is a schematic diagram illustrating an example of a method for manufacturing a sintered body according to an embodiment. FIG. 5D is a schematic diagram illustrating an example of a method for manufacturing a sintered body according to an embodiment. FIG. 6 is a three-view diagram showing an example of an insert according to an embodiment. FIG. 7 is a front view showing an example of a cutting tool according to an embodiment. FIG. 8A is a schematic diagram showing one step of a method for manufacturing a machined product according to an embodiment. 8B and 8C are schematic diagrams illustrating steps of a method for manufacturing a machined product according to an embodiment.

[0005] Hereinafter, modes for carrying out the methods for manufacturing a sintered body, an insert, a cutting tool, and a machined product according to the present disclosure (hereinafter referred to as "embodiments") will be described in detail with reference to the drawings. The methods for manufacturing a sintered body, an insert, a cutting tool, and a machined product according to the present disclosure are not limited to these embodiments. The embodiments can be appropriately combined within the scope of not causing contradictions in content. In the following embodiments, the same parts are assigned the same reference numerals, and duplicate explanations will be omitted.

[0006] In the following embodiments, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "perpendicular," or "parallel" in a strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision or installation precision.

[0007] For ease of understanding, the drawings may show an orthogonal coordinate system in which mutually perpendicular X-axis, Y-axis, and Z-axis directions are defined, with the positive Z-axis direction being the vertically upward direction.

[0008] Conventional methods for producing three-dimensional objects require the mixing of a large amount of binder into ceramic or metal powder, compared to the mold-molding method commonly used for producing sintered bodies. Conventional methods for producing three-dimensional objects involve densely and tightly injecting a compound from a nozzle, which can easily result in the formation of non-uniform voids in the metal or ceramic product due to the large amount of binder when the three-dimensional object is sintered. Such non-uniform voids can affect the durability of the metal or ceramic product. For example, when a metal or ceramic product is manufactured as an insert for a cutting tool that is subjected to a large load during use, the non-uniform voids can significantly affect the durability of the metal or ceramic product.

[0009] As described above, the conventional techniques have room for further improvement in terms of improving the durability of the sintered body.

[0010] Therefore, there is a need for a technology that can overcome the above-mentioned problems and improve durability.

[0011] <Sintered body> First, an example of a sintered body according to the embodiment will be described. FIG. 1 is a plan view showing an example of a sintered body according to the embodiment. FIG. 2A is a cross-sectional view showing an example of a cross section of a sintered body taken along line A-A' shown in FIG. 1. FIG. 2B is a cross-sectional view showing an example of a cross section of a sintered body taken along line B-B' shown in FIG. 1. The colored portions in FIGS. 1, 2A, and 2B indicate spaces. The sintered body 1 according to the embodiment is a structure obtained by sintering inorganic raw materials.

[0012] As shown in Fig. 1 , the sintered body 1 includes a sintered body main body 10. The sintered body main body 10 has an outer region 20 and an inner region 30 surrounded by the outer region 20. The outer region 20 may surround the entire inner region 30, or may surround a portion of the inner region 30. For example, as shown in Figs. 1 , 2A, and 2B , the outer region 20 may surround the sides (X direction and Y direction) and bottom (negative Z direction) of the inner region 30 without surrounding the top (positive Z direction) of the inner region 30.

[0013] 2A and 2B, the inner region 30 includes a plurality of first layers 40 and a plurality of second layers 50. The plurality of second layers 50 are stacked alternately with the plurality of first layers 40. The outer region 20 does not include a plurality of first layers 40 or a plurality of second layers 50.

[0014] 1, 2A, and 2B, each of the plurality of first layers 40 includes a plurality of first hard members 60 arranged side by side in a first direction (e.g., X direction). Each of the plurality of second layers 50 includes a plurality of second hard members 70 arranged side by side in a second direction (e.g., Y direction) intersecting the first direction (e.g., X direction).

[0015] Each of the multiple first hard members 60 is a member extending in a second direction (e.g., the Y direction). Each of the multiple second hard members 70 is a member extending in a first direction (e.g., the X direction). That is, multiple first hard members 60 extending in the second direction (e.g., the Y direction) and multiple second hard members 70 extending in the first direction (e.g., the X direction) are alternately stacked. As a result, the inner region 30 of the sintered body 10 has a lattice-like structure formed by the multiple first hard members 60 and the multiple second hard members 70.

[0016] 1, 2A, and 2B, a space is provided between adjacent first hard members 60 in the plurality of first hard members 60. A space is provided between adjacent second hard members 70 in the plurality of second hard members 70. The space provided between adjacent first hard members 60 and the space provided between adjacent second hard members 70 are connected.

[0017] The plurality of first hard members 60 contain a first inorganic material. For example, the plurality of first hard members 60 are formed of a first inorganic material. The plurality of second hard members 70 contain a second inorganic material. For example, the plurality of second hard members 70 are formed of a second inorganic material. The first inorganic material and the second inorganic material may be the same inorganic material or different inorganic materials. Examples of inorganic materials include cemented carbide, cermet, boron nitride sintered body, ceramics, polycrystalline diamond (PCD), and metal.

[0018] The cemented carbide contains at least W (tungsten). The cemented carbide containing W contains, for example, a hard phase containing WC (tungsten carbide). The cemented carbide may contain a binder phase containing at least one iron group element such as Ni (nickel) and Co (cobalt). As an example, the inorganic material is a WC-based cemented carbide whose hard phase components are hard particles made of WC and whose binder phase is mainly composed of Co. When the inorganic material is a cemented carbide, the plurality of first hard members 60 and / or the plurality of second hard members 70 have superior heat resistance properties.

[0019] The cermet contains, for example, Ti (titanium). The cermet containing Ti contains, for example, TiC (titanium carbide) or TiN (titanium nitride). The cermet may contain at least one iron group element such as Ni and Co.

[0020] The ceramics are, for example, Al ２ O ３ Contains aluminum oxide. ２ O ３ is, for example, κ-Al ２ O ３ and α-Al ２ O ３ The ceramic may contain other elements in addition to aluminum oxide. For example, the ceramic may contain, in addition to aluminum oxide, at least one of magnesium (Mg), calcium (Ca), strontium (Sr), silicon (Si), and a Group 3 element of the periodic table.

[0021] Metals include, for example, stainless steel, Inconel 718, 64 titanium, aluminum alloys, tungsten alloys, and the like.

[0022] The sintered body 1 may be composed of one member or multiple members. For example, as shown in the example of Fig. 6, the sintered body 1 (insert body 10A) may have one base body 10a and multiple cutting portions 10b. The base body 10a may be made of the above-mentioned cemented carbide, cermet, or ceramics. The cutting portions 10b may be made of the above-mentioned boron nitride sintered body or polycrystalline diamond.

[0023] The boron nitride sintered body may be a cubic boron nitride sintered body containing cubic boron nitride (cBN) particles. The boron nitride sintered body is not limited to cubic boron nitride (cBN) particles, but may also contain particles of hexagonal boron nitride (hBN), rhombohedral boron nitride (rBN), wurtzite boron nitride (wBN), or the like.

[0024] The sintered body 1 may be configured such that multiple components are joined together at the pre-sintered compact stage and then fired simultaneously, or such that multiple components are fired individually and then joined together.

[0025] As described above, the inner region 30 of the sintered body 10 includes spaces provided between the plurality of first hard members 60 and spaces provided between the plurality of second hard members 70. Therefore, it is possible to increase the specific surface area of ​​the sintered body 10 in the inner region 30 of the sintered body 10.

[0026] Therefore, even in a method for manufacturing a three-dimensional object using an inorganic material and a large amount of binder, debinding to remove the binder from the three-dimensional object to be manufactured is promoted. This makes it possible to improve the uniformity of pores formed in the three-dimensional object due to the large amount of binder. In this way, it is possible to reduce the non-uniformity of pores that affect the durability of the sintered body main body 10, thereby improving the durability of the sintered body 1.

[0027] When the sintered body 1 is used, the load applied to the sintered body 1 can be reduced by the spaces provided between the plurality of first hard members 60 and the spaces provided between the plurality of second hard members 70. As a result, the durability of the sintered body 1 can be improved.

[0028] This reduces the time required for the degreasing process of the three-dimensional object to be produced, thereby reducing the cost of degreasing the three-dimensional object, and also reduces the amount of inorganic raw material required to produce the three-dimensional object.

[0029] As described above, in the inner region 30 of the sintered body 10, a plurality of first hard members 60 extending in the second direction (e.g., Y direction) and a plurality of second hard members 70 extending in the first direction (e.g., X direction) are alternately stacked. This makes it easier to ensure the structural strength required for the sintered body 10, thereby improving the durability of the sintered body 1.

[0030] The inner region 30 of the sintered body 10 includes spaces between the plurality of first hard members 60 and spaces between the plurality of second hard members 70. When a refrigerant is supplied to the sintered body 10, the refrigerant can be dispersed in these spaces. Examples of refrigerants for cooling the sintered body 10 include liquids such as water. In other words, the specific surface area of ​​the sintered body 10 can be increased in the inner region 30 of the sintered body 10, thereby improving the cooling effect of the refrigerant on the sintered body 10. As a result, the durability of the sintered body 10 can be further improved. In other words, the life of the sintered body 10 can be extended.

[0031] The second direction may be orthogonal to the first direction. That is, the second direction in which the plurality of second hard members 70 are arranged side by side may be orthogonal to the first direction in which the plurality of first hard members 60 are arranged side by side. Here, "the second direction may be orthogonal to the first direction" includes the second direction being strictly orthogonal to the first direction and the second direction being substantially orthogonal to the first direction. The second direction being substantially orthogonal to the first direction means that the angle of the second direction with respect to the first direction is between 85 degrees and 90 degrees.

[0032] In this case, it is possible to increase the volume of the space provided between the plurality of first hard members 60 and the space provided between the plurality of second hard members 70. Therefore, it is possible to further increase the specific surface area of ​​the sintered body body 10 in the inner region 30 of the sintered body body 10. It is possible to increase the total contact area of ​​the plurality of first hard members 60 and the plurality of second hard members 70. As a result, it is possible to further improve the durability of the sintered body 1. It is possible to further reduce the cost of manufacturing a three-dimensionally shaped body. It is possible to further improve the cooling effect of the sintered body body 10 by the refrigerant.

[0033] The composition of the second inorganic material may be the same as the composition of the first inorganic material. That is, the composition of the second inorganic material contained in the plurality of second hard members 70 may be the same as the composition of the first inorganic material contained in the plurality of first hard members 60. For example, the plurality of first hard members 60 and the plurality of second hard members 70 are formed of the same inorganic material.

[0034] In this case, it is possible to reduce deformation of the sintered body 1 obtained by sintering the three-dimensionally shaped body to be manufactured. Even when the temperature of the sintered body 1 rises, it is possible to reduce stress at the boundary between the plurality of first hard members 60 and the plurality of second hard members 70 due to the difference in thermal expansion coefficient between the first hard members 60 and the second hard members 70. As a result, it is possible to further improve the durability of the sintered body 1. In other words, it is possible to extend the life of the sintered body 1.

[0035] 2A , the average value of the thickness t1 of the multiple first hard members 60 in the direction in which the multiple first layers 40 and the multiple second layers 50 are stacked (e.g., the Z direction) may be smaller than the average value of the width w1 of the multiple first hard members 60 in the first direction (e.g., the X direction). As shown in FIG. 2B , the average value of the thickness t2 of the multiple second hard members 70 in the direction in which the multiple first layers 40 and the multiple second layers 50 are stacked (e.g., the Z direction) may be smaller than the average value of the width w2 of the multiple second hard members 70 in the second direction (e.g., the Y direction).

[0036] In this case, it is possible to increase the contact area between the plurality of first hard members 60 and the plurality of second hard members 70. As a result, it is possible to more easily ensure the structural strength required for the sintered body 10, and therefore the durability of the sintered body 1 can be further improved.

[0037] 2A, the average value of the width w1 of the plurality of first hard members 60 in the first direction (e.g., X direction) may be larger than the average value of the spacing d1 between adjacent first hard members 60 among the plurality of first hard members 60 in the first direction (e.g., X direction). As shown in Fig. 2B, the average value of the width w2 of the plurality of second hard members 70 in the second direction (e.g., Y direction) may be larger than the average value of the spacing d2 between adjacent second hard members 70 among the plurality of second hard members 70 in the second direction (e.g., Y direction).

[0038] In this case, it is possible to increase the contact area between the plurality of first hard members 60 and the plurality of second hard members 70. As a result, it is possible to more easily ensure the structural strength required for the sintered body 10, and therefore the durability of the sintered body 1 can be further improved.

[0039] Fig. 3A is an enlarged view showing an example of a region R1 shown in Fig. 2B, and Fig. 3B is an enlarged view showing an example of a region R2 shown in Fig. 2A.

[0040] 3A, at least one of the plurality of first hard members 60 may have a first protrusion 65 that protrudes in the direction (e.g., Z direction) in which the plurality of first layers 40 and the plurality of second layers 50 are stacked. As shown in Fig. 3B, at least one of the plurality of second hard members 70 may have a second protrusion 75 that protrudes in the direction (e.g., Z direction) in which the plurality of first layers 40 and the plurality of second layers 50 are stacked.

[0041] In this case, at least one of the plurality of first hard members 60 has the first protrusion 65, which makes it possible to improve the structural strength of at least one of the plurality of first hard members 60. At least one of the plurality of second hard members 70 has the second protrusion 75, which makes it possible to improve the structural strength of at least one of the plurality of second hard members 70. Therefore, it becomes possible to further improve the durability of the sintered body 1.

[0042] Fig. 4A is a front view showing an example of the outer region 20 of the sintered body 1 according to the embodiment in the Y direction shown in Fig. 1. Fig. 4B is a front view showing an example of the outer region 20 of the sintered body 1 according to the embodiment in the X direction shown in Fig. 1.

[0043] As shown in Figures 2A, 2B, 4A, and 4B, the outer region 20 has through holes 80 that connect to at least one of the spaces between adjacent first hard members 60 among the plurality of first hard members 60 and the spaces between adjacent second hard members 70 among the plurality of second hard members 70.

[0044] In this case, during firing of the three-dimensionally shaped body, the debinding process of removing the binder is accelerated through the spaces between adjacent first hard members 60 among the plurality of first hard members 60, the spaces between adjacent second hard members 70 among the plurality of second hard members 70, and the through-holes 80. As a result, it is possible to further improve the uniformity of the pores formed in the three-dimensionally shaped body due to the large amount of binder. Therefore, it is possible to further improve the durability of the sintered body 1.

[0045] When a refrigerant is supplied to the sintered body 10 through the spaces between adjacent first hard members 60 and the spaces between adjacent second hard members 70, the refrigerant can be discharged to the outside of the sintered body 10 through the through-holes 80. The spaces between adjacent first hard members 60, the spaces between adjacent second hard members 70, and the through-holes 80 make it easier to form a refrigerant flow path, thereby improving the cooling effect of the sintered body 10 by the refrigerant. As a result, the durability of the sintered body 1 can be further improved. In other words, the life of the sintered body 1 can be extended.

[0046] Next, an example of a method for manufacturing a sintered body according to the embodiment will be described. Figures 5A, 5B, 5C, and 5D are schematic diagrams illustrating an example of a method for manufacturing a sintered body according to the embodiment. Hatched areas in Figures 5A, 5B, 5C, and 5D indicate spaces.

[0047] First, inorganic pellets are prepared as raw materials for forming the outer region 20 on the lower surface side (e.g., in the negative Z-axis direction) of the sintered body 10 of the sintered body 1. A suitable fluidizing agent or the like is added to the prepared inorganic pellets to obtain a mixture of the inorganic pellets, the fluidizing agent, and the like. The fluidizing agent may be a binder used in sintering the inorganic material.

[0048] The resulting mixture is then fed into the nozzle of a fused deposition modeling (FDM) 3D printer. The inorganic pellets in the mixture are heated and melted within the nozzle. In this way, a fluid containing the melted inorganic pellets and a superplasticizer is produced.

[0049] Next, the nozzle is moved and fluid is extruded from the nozzle in a predetermined pattern to form an outer region 20 on the underside (e.g., in the negative Z-axis direction) of the sintered body 10. In this way, a molded object of the outer region 20 on the underside (e.g., in the negative Z-axis direction) of the sintered body 10 is obtained.

[0050] For example, as shown in FIG. 5A, the nozzle is moved as indicated by the arrow from one corner of the outer region 20 on the lower surface side of the sintered body 10 (for example, in the negative Z-axis direction) and fluid is extruded from the nozzle.

[0051] Specifically, a line of fluid extending in the second direction (e.g., the Y direction) is formed by moving the nozzle in the second direction (e.g., the Y direction) and forcing fluid out of the nozzle. Next, the nozzle is moved in a first direction (e.g., the X direction) perpendicular to the second direction (e.g., the Y direction) by a distance equal to the width of the line of fluid. Next, the nozzle is moved in the opposite direction in the second direction (e.g., the Y direction) and forcing fluid out of the nozzle, thereby forming a line of fluid adjacent to the previously formed line of fluid.

[0052] By repeating the formation of fluid lines in this manner, a layer corresponding to the outer region 20 on the lower surface side (e.g., in the negative Z-axis direction) of the sintered body body 10 is formed. However, if it is not necessary to form the outer region 20 on the lower surface side (e.g., in the negative Z-axis direction) of the sintered body body 10, the step of forming the outer region 20 on the lower surface side (e.g., in the negative Z-axis direction) of the sintered body body 10 is omitted.

[0053] Next, pellets of a second inorganic material are prepared as a raw material for forming the second layer 50 in the inner region 30 of the sintered body 10 of the sintered body 1. A suitable second fluidizing agent, etc. is added to the prepared pellets of the second inorganic material to obtain a second mixture of pellets of the second inorganic material, the second fluidizing agent, etc. The second fluidizing agent may be a binder used in sintering the second inorganic material.

[0054] The resulting second mixture is then fed into the nozzle of a fused deposition modeling (FDM) 3D printer. The pellets of the second inorganic material in the second mixture are heated and melted within the nozzle. In this way, a second fluid containing the melted pellets of the second inorganic material and the second fluidizing agent is produced.

[0055] Next, the nozzle is moved in accordance with a predetermined pattern for forming the second layer 50 in the inner region 30 of the sintered body 10, and the second fluid is extruded from the nozzle onto the shaped object in the outer region 20 on the underside of the sintered body 10 (e.g., in the negative Z-axis direction), thereby forming a layer of the second fluid in accordance with the predetermined pattern. The predetermined pattern includes a pattern corresponding to a plurality of second hard members 70 arranged in a second direction (e.g., the Y direction). In this manner, a shaped object of the second layer 50 in the inner region 30 of the sintered body 10 is obtained.

[0056] For example, as shown in Figure 5B, the nozzle is moved as indicated by the arrow from one corner of the second layer 50 in the inner region 30 of the sintered body body 10, and the second fluid is extruded from the nozzle onto the shaped object in the outer region 20 on the underside of the sintered body body 10 (e.g., in the negative Z-axis direction).

[0057] Specifically, a line of the second fluid extending in the first direction (e.g., the X direction) is formed by moving the nozzle in a first direction (e.g., the X direction) and extruding the second fluid from the nozzle. The line of the second fluid corresponds to the second hard member 70. The width of the line of the second fluid in the second direction (e.g., the Y direction) corresponds to the width w2 of the second hard member 70 in the second direction (e.g., the Y direction).

[0058] The thickness of the line of the second fluid in a direction (e.g., Z direction) perpendicular to the first direction (e.g., X direction) and the second direction (e.g., Y direction) corresponds to the thickness t2 of the second hard member 70 in a direction (e.g., Z direction) perpendicular to the first direction (e.g., X direction) and the second direction (e.g., Y direction).

[0059] Next, the nozzle is moved in a second direction (e.g., Y direction) intersecting the first direction (e.g., X direction) by a distance corresponding to the interval d2 between adjacent second hard members 70. Next, the nozzle is moved in the opposite direction in the first direction (e.g., X direction) and the second fluid is extruded from the nozzle onto the shaped object in the outer region 20 on the underside of the sintered body 10 (e.g., the negative direction of the Z axis), thereby forming lines of the second fluid spaced apart by the distance corresponding to the interval d2 between adjacent second hard members 70.

[0060] By repeating the formation of the lines of the second fluid in this manner, a layer corresponding to the second layer 50 including a plurality of second hard members 70 in the inner region 30 of the sintered body 10 is formed.

[0061] Next, pellets of a first inorganic material are prepared as raw material for forming the first layer 40 in the inner region 30 of the sintered body 10 of the sintered body 1. A suitable first fluidizing agent, etc. is added to the prepared pellets of the first inorganic material to obtain a first mixture of pellets of the first inorganic material, the first fluidizing agent, etc. The first fluidizing agent may be a binder used for sintering the first inorganic material.

[0062] The resulting first mixture is then fed into the nozzle of a fused deposition modeling (FDM) 3D printer. The pellets of the first inorganic material in the first mixture are heated and melted within the nozzle. In this way, a first fluid containing the melted pellets of the first inorganic material, a first fluidizer, and the like is produced.

[0063] Next, the nozzle is moved in accordance with a predetermined pattern for forming the first layer 40 in the inner region 30 of the sintered body 10, and the first fluid is extruded from the nozzle onto the shaped object of the second layer 50 in the inner region 30 of the sintered body 10, thereby forming a layer of the first fluid in accordance with the predetermined pattern. The predetermined pattern includes a pattern corresponding to a plurality of first hard members 60 arranged in a first direction (e.g., the X direction). In this manner, a shaped object of the first layer 40 in the inner region 30 of the sintered body 10 is obtained.

[0064] For example, as shown in Figure 5C, the nozzle is moved as indicated by the arrow from one corner of the first layer 40 in the inner region 30 of the sintered body body 10, and the first fluid is extruded from the nozzle onto the shaped object of the second layer 50 in the inner region 30 of the sintered body body 10.

[0065] Specifically, by moving the nozzle in the second direction (e.g., the Y direction) and extruding the first fluid from the nozzle, a line of the first fluid extending in the second direction (e.g., the Y direction) is formed. The line of the first fluid corresponds to the first hard member 60. The width of the line of the first fluid in the first direction (e.g., the X direction) corresponds to the width w1 of the first hard member 60 in the first direction (e.g., the X direction).

[0066] The thickness of the line of the first fluid in a direction (e.g., Z direction) perpendicular to the first direction (e.g., X direction) and the second direction (e.g., Y direction) corresponds to the thickness t1 of the first hard member 60 in a direction (e.g., Z direction) perpendicular to the first direction (e.g., X direction) and the second direction (e.g., Y direction).

[0067] Next, the nozzle is moved in a first direction (e.g., X direction) intersecting with a second direction (e.g., Y direction) by a distance corresponding to the interval d1 between adjacent first hard members 60. Next, the nozzle is moved in the opposite direction in the second direction (e.g., Y direction) and the first fluid is extruded from the nozzle onto the shaped object of the second layer 50 in the inner region 30 of the sintered body body 10, thereby forming lines of the first fluid spaced apart by the distance corresponding to the interval d1 between adjacent first hard members 60.

[0068] By repeating the formation of the lines of the first fluid in this manner, a layer corresponding to the first layer 40 including a plurality of first hard members 60 in the inner region 30 of the sintered body 10 is formed.

[0069] Next, the step of obtaining a shaped product of the second layer 50 in the inner region 30 of the sintered body 10 and the step of obtaining a shaped product of the first layer 40 in the inner region 30 of the sintered body 10 are alternately repeated to form a stack of the shaped product of the second layer 50 and the shaped portion of the first layer 40. In this manner, a shaped product of the inner region 30 of the sintered body 10 is obtained.

[0070] Next, inorganic material pellets are prepared as raw materials for forming the outer region 20 on the upper surface side (e.g., in the positive Z-axis direction) of the sintered body 10 of the sintered body 1. A suitable fluidizer or the like is added to the prepared inorganic material pellets to obtain a mixture of the inorganic material pellets, the fluidizer, and the like. The fluidizer may be a binder used for sintering inorganic materials. The inorganic material pellets and the fluidizer for forming the outer region 20 on the upper surface side (e.g., in the positive Z-axis direction) of the sintered body 10 of the sintered body 1 are the same as the inorganic material pellets and the fluidizer for forming the outer region 20 on the lower surface side (e.g., in the negative Z-axis direction) of the sintered body 10 of the sintered body 1.

[0071] The resulting mixture is then fed into the nozzle of a fused deposition modeling (FDM) 3D printer. The inorganic pellets in the mixture are heated and melted within the nozzle. In this way, a fluid containing the melted inorganic pellets and a superplasticizer is produced.

[0072] Next, the nozzle is moved in a predetermined pattern to form the outer region 20 on the upper surface side (e.g., in the positive Z-axis direction) of the sintered body 10, and the fluid is extruded from the nozzle onto the shaped object in the inner region 30 of the sintered body 10, thereby forming a layer of the fluid in the predetermined pattern. In this way, a shaped object in the outer region 20 on the upper surface side (e.g., in the positive Z-axis direction) of the sintered body 10 is obtained.

[0073] 5D , the nozzle is moved as indicated by the arrow from one corner of the outer region 20 on the upper surface side of the sintered body 10 (e.g., in the positive direction of the Z axis) and the fluid is extruded from the nozzle. Specifically, the nozzle is moved sequentially in the second direction (e.g., the Y direction), the first direction (e.g., the X direction), the reverse direction in the second direction (e.g., the Y direction), and the reverse direction in the first direction (e.g., the X direction) and the fluid is extruded from the nozzle onto the shaped object in the inner region 30 of the sintered body 10, thereby forming a line of fluid surrounding the inner region 30. In this way, a layer corresponding to the outer region 20 on the upper surface side of the sintered body 10 (e.g., in the positive direction of the Z axis) is formed.

[0074] Next, inorganic material pellets are prepared as raw materials for forming the outer region 20 on the side surface of the sintered body main body 10 of the sintered body 1. A suitable fluidizing agent or the like is added to the prepared inorganic material pellets to obtain a mixture of the inorganic material pellets, the fluidizing agent, etc. The fluidizing agent may be a binder used in sintering the inorganic material.

[0075] The inorganic material pellets and fluidizing agent for forming the outer region 20 on the side of the sintered body 10 of the sintered body 1 are the same as the inorganic material pellets and fluidizing agent for forming the outer region 20 on the bottom side (e.g., in the negative Z-axis direction) and top side (e.g., in the positive Z-axis direction) of the sintered body 10 of the sintered body 1, respectively.

[0076] The resulting mixture is then fed into the nozzle of a fused deposition modeling (FDM) 3D printer. The inorganic pellets in the mixture are heated and melted within the nozzle. In this way, a fluid containing the melted inorganic pellets and a superplasticizer is produced.

[0077] Next, the nozzle is moved in a predetermined pattern to form the outer region 20 on the side surface of the sintered body 10, and fluid is extruded from the nozzle onto the side surface of the shaped product of the inner region 30 of the sintered body 10, thereby forming a layer of fluid in the predetermined pattern. In this way, a shaped product of the outer region 20 on the side surface of the sintered body 10 is obtained.

[0078] Next, the shaped product of the sintered body 10 obtained as described above is fired in a vacuum or a non-oxidizing atmosphere to obtain a sintered body 1 including the sintered body 10 having the outer region 20 and the inner region 30. The surface of the sintered body 10 of the obtained sintered body 1 may be polished or honed. For example, a polishing machine may be used to polish the side surface of the sintered body 10 of the sintered body 1. For example, a drill may be used to form a through hole 80 in the side surface of the sintered body 10 of the sintered body 1. For example, a honing machine may be used to hone the inner surface of the through hole 80 in the sintered body 10 of the sintered body 1.

[0079] Thereafter, a coating film may be formed on the surface of the sintered body 10 of the sintered body 1 by chemical vapor deposition (CVD) or physical vapor deposition (PVD).

[0080] In this manner, the sintered body 1 including the sintered body main body 10 having the outer region 20 and the inner region 30 can be manufactured.

[0081] The second direction may be perpendicular to the first direction. The composition of the second inorganic material may be the same as the composition of the first inorganic material. When the composition of the second inorganic material is the same as the composition of the first inorganic material, the composition of the second fluidizing agent may be the same as the composition of the first fluidizing agent. When the compositions of the second inorganic material and the second fluidizing agent are the same as the compositions of the first inorganic material and the first fluidizing agent, respectively, it becomes possible to integrate the process of obtaining the second mixture and the process of obtaining the first mixture. In other words, it becomes possible to more easily manufacture the sintered body 1.

[0082] The composition of the inorganic material may be the same as the composition of the second inorganic material and / or the composition of the first inorganic material. In this case, the composition of the fluidizer may be the same as the composition of the second fluidizer and / or the composition of the fluidizer of the first inorganic material. When the composition of the inorganic material and the composition of the fluidizer are the same as the composition of the first inorganic material and the composition of the first fluidizer, respectively, it becomes possible to integrate the steps of obtaining a mixture and obtaining a second mixture and / or obtaining a first mixture. In other words, it becomes possible to more easily manufacture the sintered body 1.

[0083] To provide at least one of the multiple first hard members 60 with a first protrusion 65 protruding in a direction (e.g., Z direction) perpendicular to the first direction (e.g., X direction) and the second direction (e.g., Y direction), for example, the amount of first fluidizer added to the pellets of the first inorganic material when obtaining the first mixture is increased. In this case, it is possible to increase the fluidity of the first fluid containing the molten pellets of the first inorganic material and the first fluidizer. By using a first fluid with such increased fluidity, it is possible to form a structure corresponding to the first protrusion 65 by the weight of the first fluid.

[0084] To provide at least one of the multiple second hard members 70 with a second protrusion 75 protruding in a direction (e.g., Z direction) perpendicular to the first direction (e.g., X direction) and the second direction (e.g., Y direction), for example, the amount of second fluidizer added to the pellets of the second inorganic material when obtaining the second mixture is increased. In this case, it is possible to increase the fluidity of the second fluid containing the molten pellets of the second inorganic material and the second fluidizer. By using a second fluid with such increased fluidity, it is possible to form a structure corresponding to the second protrusion 75 by the weight of the second fluid.

[0085] The process for obtaining a molded object of the outer region 20 on the upper surface side of the sintered body 10 (e.g., in the positive direction of the Z axis) may be similar to the process for obtaining a molded object of the outer region 20 on the lower surface side of the sintered body 10 (e.g., in the negative direction of the Z axis).

[0086] For example, the sintered body 1 can be applied to an insert used in cutting a work material.

[0087] <Insert> Fig. 6 is a three-view diagram showing an example of an insert according to an embodiment. As shown in Fig. 6, an insert 1A according to an embodiment includes an insert body 10A. The insert 1A is used for cutting a workpiece.

[0088] The insert body 10A is, for example, a hexahedron having an upper surface 11, a lower surface 12, and four side surfaces 13. The upper surface 11 is an example of a first surface. The lower surface 12 is an example of a second surface. The lower surface 12 is located on the opposite side of the upper surface 11. The four side surfaces 13 are located between the upper surface 11 and the lower surface 12. The shapes of the upper surface 11 and the lower surface 12 are, for example, parallelograms (squares in FIG. 6 ). The shapes of each side surface 13 are, for example, rectangular.

[0089] The insert body 10A has a through-hole 15 at the center thereof that passes through the insert body 10A in the up-down direction (e.g., Z direction). The through-hole 15 has openings on the upper surface 11 and the lower surface 12. A screw 95 is inserted into the through-hole 15 to attach the insert 1A to a holder 90 (described later) (see FIG. 7).

[0090] The insert body 10A has a cutting edge 14 at one or two corners of the insert body 10A. The cutting edge 14 is provided at least part of the area where the upper surface 11 or the lower surface 12 and the side surface 13 intersect.

[0091] 6, when the cutting edge 14 is provided at least in a portion where the top surface 11 and the side surface 13 intersect, the top surface 11 functions as a so-called rake face, and the side surface 13 functions as a so-called flank face. The insert 1A cuts the workpiece by bringing the cutting edge 14 into contact with the workpiece.

[0092] As shown in Fig. 6, the insert body 10A includes the sintered body 1 (see Fig. 1). Accordingly, the insert body 10A includes a sintered body body 10 (see Fig. 1) included in the sintered body 1. The sintered body body 10 has an outer region 20A and an inner region 30A surrounded by the outer region 20A. The inner region 30A includes a plurality of first layers 40A and a plurality of second layers 50A stacked alternately with the plurality of first layers 40A.

[0093] The direction (e.g., Z direction) in which the plurality of first layers 40A and the plurality of second layers 50A included in the inner region 30A are stacked may be a direction perpendicular to the upper surface 11 or the lower surface 12. Each of the plurality of first layers 40A includes a plurality of first hard members 60A arranged side by side in a first direction (e.g., X direction). Each of the plurality of second layers 50A includes a plurality of second hard members 70A arranged side by side in a second direction (e.g., Y direction) intersecting the first direction (e.g., X direction).

[0094] The upper surface 11, the lower surface 12, and the side surface 13 of the insert body 10A correspond to the upper surface, the lower surface, and the side surface of the outer region 20A included in the sintered body body 10 of the sintered body 1, respectively.

[0095] In the insert body 10A, the outer region 20A and the inner region 30A are provided with through holes 15. Accordingly, the plurality of first hard members 60A and the plurality of second hard members 70A have shapes that form the through holes 15. In the insert body 10A, the inner region 30A is covered by the outer region 20A except for the through holes 15.

[0096] 6 is merely an example and does not limit the shape of the insert 1A according to the present disclosure. For example, the upper surface 11 and the lower surface 12 of the insert body 10A may be rhombic. For example, the cutting edge 14 may be provided on at least a portion of the intersection between the upper surface 11 and the side surface 13 and at least a portion of the intersection between the lower surface 12 and the side surface 13.

[0097] The insert 1A may include a coating layer (not shown). The coating layer covers at least a part of the surface of the insert body 10A. In this case, it is possible to improve the wear resistance, heat resistance, etc. of the insert body 10A.

[0098] The coating layer is, for example, Al ａ Ti ｂ M ｃand at least one nonmetal selected from carbon, nitrogen, and oxygen. M is at least one metal selected from Groups 4, 5, and 6 of the periodic table of elements (excluding chromium (Cr)) and silicon (Si). a, b, and c are 0≦a≦65 and 0≦b≦100, and a+b+c=100. As an example, the composition of the coating layer may be AlTiWNbSiN. The notation AlTiWNbSiN indicates the types of constituent elements and does not indicate that the atomic ratio of the constituent elements is equal. The coating layer does not necessarily contain M. In this case, the composition of the coating layer may be AlTiN, for example. The notation AlTiN indicates the types of constituent elements and does not indicate that the atomic ratio of the constituent elements is equal. The coating layer has high hardness at high temperatures (e.g., 1100°C) and high oxidation resistance.

[0099] The thickness of the coating layer may be 1 μm or more and 7 μm or less. In particular, when the thickness of the coating layer is 1.5 μm or more, it is possible to more easily improve the wear resistance of the insert 1A. When the thickness of the coating layer is 3 μm or less, it is possible to more easily improve the fracture resistance of the coating layer.

[0100] Because the insert 1A includes the sintered body 1, the durability of the insert 1A including the sintered body 1 can be improved. More specifically, when the insert 1A including the insert body 10A is used, the spaces provided between the plurality of first hard members 60A and the spaces provided between the plurality of second hard members 70A can reduce the cutting load applied to the insert body 10A. As a result, the durability of the insert 1A including the insert body 10A can be improved. Accordingly, the service life of the insert 1A including the insert body 10A can be increased.

[0101] When an insert 1A including the insert body 10A is used to cut a workpiece, the temperature of the insert body 10A rises to several hundred degrees Celsius. The insert body 10A may have a plurality of through holes 80 (see FIGS. 1, 2A, and 2B) on the side surface 13 of the insert body 10A. In this case, a refrigerant can be circulated through the flow passages formed by the plurality of through holes 80, the spaces between the plurality of first hard members 60A, and the spaces between the plurality of second hard members 70A. In this way, the insert body 10A including the sintered body 1 can be cooled by the refrigerant. As a result, the service life of the insert 1A including the insert body 10A can be increased.

[0102] For example, the insert 1A including the insert body 10A can be manufactured by a method similar to the method for manufacturing the sintered body 1 including the sintered body body 10. However, when manufacturing the shaped object of the second layer 50A in the inner region 30A of the sintered body body 10 and the shaped object of the first layer 40A in the inner region 30A of the sintered body body 10, a layer corresponding to the second layer 50A including a plurality of second hard members 70 and a layer corresponding to the first layer 40A including a plurality of first hard members 60 are formed so as to form the through-holes 15. In other words, for the portion corresponding to the through-holes 15, the nozzle is moved without extruding the fluid for forming the layer corresponding to the second layer 50A and the layer corresponding to the first layer 40A from the nozzle.

[0103] <Cutting Tool> Next, a cutting tool including the insert 1A described above will be described with reference to Fig. 7. Fig. 7 is a front view showing an example of a cutting tool according to this embodiment.

[0104] As shown in FIG. 7, a cutting tool 100 according to this embodiment includes an insert 1A and a holder 90 for fixing the insert 1A.

[0105] The holder 90 is a rod-shaped member extending from its front end (upper end in FIG. 7 ) to its rear end (lower end in FIG. 7 ). The holder 90 is made of, for example, steel or cast iron. Of these materials, steel may be used, as it has high toughness.

[0106] The holder 90 has a pocket 93 located at the end on the tip side. The pocket 93 is the portion where the insert 1A 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 95, which will be described later, is threaded.

[0107] The insert 1A is positioned in a pocket 93 of the holder 90 and is attached to the holder 90 by a screw 95. That is, the screw 95 is inserted into the through hole 15 of the insert 1A, and the tip of the screw 95 is inserted into a threaded hole formed in the seating surface of the pocket 93 to screw the threaded portions together. In this way, the insert 1A is attached to the holder 90 so that the cutting edge 14 protrudes outward from the holder 90.

[0108] Examples of cutting processes using cutting tools include turning and milling. Examples of turning processes include internal diameter machining, external diameter machining, grooving, and cut-off. Examples of milling processes include milling processes such as face milling, flat milling, side milling, and groove milling, and end milling processes such as single-blade end milling, multi-blade end milling, tapered-blade end milling, and ball end milling.

[0109] In this embodiment, the cutting tool 100 used for so-called turning is illustrated as an example, but the cutting tool is not limited to that used for turning. For example, the insert 1A may be used in a cutting tool used for milling. Examples of cutting tools used for milling include milling cutters such as flat milling cutters, face milling cutters, side milling cutters, and groove milling cutters, and end mills such as single-blade end mills, multi-blade end mills, tapered-blade end mills, and ball end mills.

[0110] Turning is performed using a lathe. Turning includes the steps of rotating a workpiece, bringing a fixed cutting tool 100 into contact with the rotating workpiece to remove the surface of the rotating workpiece, and removing the cutting tool 100 from the workpiece. By machining the workpiece into a desired rotationally symmetric shape in this manner, it is possible to manufacture a rotationally symmetric machined product. Turning is performed using a milling machine. Turning includes the steps of rotating the cutting tool 100, bringing the rotating cutting tool 100 into contact with the fixed workpiece to remove the fixed workpiece, and removing the cutting tool 100 from the workpiece. By machining the workpiece into a desired shape in this manner, it is possible to manufacture a machined product.

[0111] In this embodiment, an example is shown in which the shapes of the upper and lower surfaces of the cutting tool 100 are parallelograms. The shapes of the upper and lower surfaces of the cutting tool 100 may be rhombic, square, etc. The shapes of the upper and lower surfaces of the cutting tool 100 may be triangular, pentagonal, hexagonal, etc. The shape of the cutting tool 100 may be a positive type or a negative type. A positive type is a type in which the side surfaces are inclined with respect to a central axis passing through the centers of the upper and lower surfaces of the cutting tool 100, and a negative type is a type in which the side surfaces are parallel to the central axis.

[0112] <Method of manufacturing machined product> Next, a method of manufacturing a machined product according to an embodiment will be described with reference to Figures 8A, 8B, and 8C. Figures 8A, 8B, and 8C are schematic views showing a step of the method of manufacturing a machined product according to an embodiment.

[0113] The machined product 200 is produced by cutting a workpiece 201. 8A, 8B, and 8C illustrate turning using a lathe as an example of cutting. The manufacturing method of the machined product 200 in this embodiment includes: a step (step A) of rotating the workpiece 201; a step (step B) of bringing the workpiece 201 into contact with the cutting tool 100; and a step (step C) of moving the cutting tool 100 relatively away from the workpiece 201.

[0114] More specifically, first, as shown in Fig. 8A, the workpiece 201 is rotated around the axis O1, and the cutting tool 100 is brought relatively close to the workpiece 201. Next, as shown in Fig. 8B, the cutting edge of the insert 1A is brought into contact with the workpiece 201 to cut the workpiece 201. Next, as shown in Fig. 8C, the cutting tool 100 is moved relatively away from the workpiece 201.

[0115] In Fig. 8A, the axis O1 is fixed and the workpiece 201 is rotated while the cutting tool 100 is moved in the Y1 direction to approach the workpiece 201. In Fig. 8B, the cutting edge of the insert 1A is brought into contact with the rotating workpiece 201 to cut the workpiece 201. In Fig. 8C, the cutting tool 100 is moved in the Y2 direction while the workpiece 201 is rotated to move away from the workpiece 201.

[0116] In the cutting process in the manufacturing method of the machined product according to the embodiment, the cutting tool 100 is moved in each step to bring the cutting tool 100 into contact with the workpiece 201 or to move the cutting tool 100 away from the workpiece 201. However, the manufacturing method of the machined product is not limited to this mode, as a matter of course.

[0117] For example, in step A, the workpiece 201 may be brought closer to the cutting tool 100. Similarly, in step C, the workpiece 201 may be moved away from the cutting tool 100. To continue the cutting process, the workpiece 201 may be kept rotating, and the step of bringing the cutting edge of the cutting tool 100 into contact with different locations on the workpiece 201 may be repeated.

[0118] When performing milling instead of turning, the cutting tool may be rotated around a rotation axis in step A. Furthermore, in step B, the workpiece 201 may be cut by bringing the cutting edge of the rotating insert 1A into contact with the workpiece 201. Furthermore, in step C, the cutting tool may be moved away from the workpiece 201. The milling may be performed using a milling machine.

[0119] Typical examples of the material of the workpiece 201 include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0120] Examples of the present disclosure will be specifically described below, but the present disclosure is not limited to the examples shown below.

[0121] First, ultra-hard raw material pellets having a size of 2 to 4 mm were prepared as raw materials for forming the sintered body of the sintered body according to the example. Stearic acid was added as a fluidizing agent to the prepared ultra-hard raw material pellets to obtain a mixture of the ultra-hard raw material pellets and stearic acid.

[0122] The resulting mixture was then poured into the nozzle of a fused deposition modeling (FDM) 3D printer to produce a fluid containing pellets of the superhard material and stearic acid, which were melted at a temperature of approximately 170°C.

[0123] Next, a shaped object of an outer region corresponding to the underside of the sintered body was obtained by extruding fluid from the nozzle according to the pattern shown in Fig. 5A. Next, a shaped object of a second layer corresponding to the inner region of the sintered body was obtained by extruding fluid according to the pattern shown in Fig. 5B. Next, a shaped object of a first layer corresponding to the inner region of the sintered body was obtained by extruding fluid according to the pattern shown in Fig. 5C.

[0124] By repeating the steps of obtaining a second-layer object and obtaining a first-layer object, a stack of second-layer objects and first-layer objects can be formed. In this manner, the inner region of the object was formed. Next, fluid was extruded from the nozzle in the pattern shown in FIG. 5D to obtain an outer region of the object corresponding to the top surface of the sintered body. Next, fluid was extruded onto the side of the obtained object to obtain an outer region of the object corresponding to the side of the sintered body. In this manner, a pre-sintered object was obtained.

[0125] Next, the obtained shaped body was heated in a so-called binder removal process to remove the binder components, and then fired, for example, in a vacuum or in an argon (Ar) atmosphere at 1350°C to 1600°C to obtain a sintered body having an outer region and an inner region surrounded by the outer region.

[0126] The inner region included a plurality of first layers and a plurality of second layers stacked alternately with the plurality of first layers, each of the plurality of first layers including a plurality of first hard members arranged side by side in a first direction, and each of the plurality of second layers including a plurality of second hard members arranged side by side in a second direction perpendicular to the first direction.

[0127] The average thickness of the plurality of first hard members in the direction in which the plurality of first layers and the plurality of second layers are stacked was smaller than the average width of the plurality of first hard members in the first direction. The average thickness of the plurality of second hard members in the direction in which the plurality of first layers and the plurality of second layers are stacked was smaller than the average width of the plurality of second hard members in the second direction.

[0128] The average width of the plurality of first hard members in the first direction was greater than the average spacing between adjacent first hard members in the first direction, and the average width of the plurality of second hard members in the second direction was greater than the average spacing between adjacent second hard members in the second direction.

[0129] The plurality of first hard members had first convex portions protruding in a direction in which the plurality of first layers and the plurality of second layers were stacked, and the plurality of second hard members had second convex portions protruding in a direction in which the plurality of first layers and the plurality of second layers were stacked.

[0130] The present technology can be configured as follows. (1) A sintered body comprising: a sintered body body having an outer region and an inner region surrounded by the outer region, wherein the inner region includes a plurality of first layers and a plurality of second layers alternately stacked with the plurality of first layers, each of the plurality of first layers including a plurality of first hard members arranged side by side in a first direction and containing a first inorganic material, and each of the plurality of second layers including a plurality of second hard members arranged side by side in a second direction intersecting the first direction and containing a second inorganic material. (2) The sintered body according to (1), wherein the second direction is orthogonal to the first direction. (3) The sintered body according to (1) or (2), wherein the composition of the second inorganic material is the same as the composition of the first inorganic material. (4) The sintered body according to any one of (1) to (3), wherein an average value of thicknesses of the plurality of first hard members in a direction in which the plurality of first layers and the plurality of second layers are stacked is smaller than an average value of widths of the plurality of first hard members in the first direction, and an average value of thicknesses of the plurality of second hard members in a direction in which the plurality of first layers and the plurality of second layers are stacked is smaller than an average value of widths of the plurality of second hard members in the second direction. (5) The sintered body according to any one of (1) to (4), wherein an average value of widths of the plurality of first hard members in the first direction is larger than an average value of intervals between adjacent first hard members among the plurality of first hard members in the first direction, and an average value of widths of the plurality of second hard members in the second direction. (6) The sintered body according to any one of (1) to (5), wherein at least one of the plurality of first hard members has a first convex portion that protrudes in a direction in which the plurality of first layers and the plurality of second layers are stacked, and at least one of the plurality of second hard members has a second convex portion that protrudes in a direction in which the plurality of first layers and the plurality of second layers are stacked.(7) The sintered body according to any one of (1) to (6), wherein the outer region has a through hole connecting to at least one of spaces between adjacent first hard members among the plurality of first hard members and spaces between adjacent second hard members among the plurality of second hard members. (8) An insert comprising an insert body, wherein the insert body includes the sintered body according to any one of (1) to (7). (9) The insert according to (8), wherein the insert body has a first surface and a second surface opposite to the first surface, and the direction in which the plurality of first layers and the plurality of second layers included in the inner region of the sintered body are stacked is perpendicular to the first surface. (10) A cutting tool comprising: a holder extending from a front end to a rear end and having a pocket located on the front end side; and the insert according to (8) or (9), located in the pocket. (11) A method for manufacturing a machined product, comprising: a step of rotating a workpiece or the cutting tool described in (10); a step of bringing the workpiece and the cutting tool into contact; and a step of moving the cutting tool relatively away from the workpiece.

[0131] Further advantages and / or 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. 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 their equivalents.

[0132] 1 Sintered body 1A Insert 10 Sintered body body 10A Insert body 10a Base body 10b Cutting portion 11 Upper surface 12 Lower surface 13 Side surface 14 Cutting edge 15 Through hole 20, 20A Outer region 30, 30A Inner region 40, 40A First layer 50, 50A Second layer 60, 60A First hard member 65 First convex portion 70, 70A Second hard member 75 Second convex portion 80 Through hole 90 Holder 93 Pocket 95 Screw 100 Cutting tool R1, R2 Region t1, t2 Thickness w1, w2 Width d1, d2 Spacing

Claims

1. A sintered body comprising: a sintered body body having an outer region and an inner region surrounded by the outer region; the inner region including a plurality of first layers and a plurality of second layers stacked alternately with the plurality of first layers; each of the plurality of first layers including a plurality of first hard members arranged side by side in a first direction and containing a first inorganic material; and each of the plurality of second layers including a plurality of second hard members arranged side by side in a second direction intersecting the first direction and containing a second inorganic material.

2. The sintered body according to claim 1, wherein the second direction is perpendicular to the first direction.

3. The sintered body according to claim 1 or 2, wherein the composition of the second inorganic material is the same as the composition of the first inorganic material.

4. A sintered body as described in any one of claims 1 to 3, wherein the average thickness of the plurality of first hard members in the direction in which the plurality of first layers and the plurality of second layers are stacked is smaller than the average width of the plurality of first hard members in the first direction, and the average thickness of the plurality of second hard members in the direction in which the plurality of first layers and the plurality of second layers are stacked is smaller than the average width of the plurality of second hard members in the second direction.

5. A sintered body according to any one of claims 1 to 4, wherein the average width of the plurality of first hard members in the first direction is greater than the average spacing between adjacent first hard members among the plurality of first hard members in the first direction, and the average width of the plurality of second hard members in the second direction is greater than the average spacing between adjacent second hard members among the plurality of second hard members in the second direction.

6. A sintered body according to any one of claims 1 to 5, wherein at least one of the plurality of first hard members has a first convex portion that protrudes in the direction in which the plurality of first layers and the plurality of second layers are stacked, and at least one of the plurality of second hard members has a second convex portion that protrudes in the direction in which the plurality of first layers and the plurality of second layers are stacked.

7. A sintered body according to any one of claims 1 to 6, wherein the outer region has through holes connecting to at least one of the spaces between adjacent first hard members among the plurality of first hard members and the spaces between adjacent second hard members among the plurality of second hard members.

8. An insert comprising an insert body, the insert body including the sintered body according to any one of claims 1 to 7.

9. The insert according to claim 8, wherein the insert body has a first surface and a second surface opposite to the first surface, and the direction in which the plurality of first layers and the plurality of second layers included in the inner region of the sintered body are stacked is perpendicular to the first surface.

10. A cutting tool comprising: a holder extending from a front end to a rear end and having a pocket located on the front end side; and an insert according to claim 8 or 9 located in the pocket.

11. A method for manufacturing a machined product, comprising the steps of: rotating a workpiece or the cutting tool described in claim 10; bringing the workpiece and the cutting tool into contact; and moving the cutting tool relatively away from the workpiece.

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