Method for manufacturing three-dimensional object and three-dimensional object

Abstract

To provide a three-dimensional manufactured object having elevated toughness and high hardness at the same time, and a method of manufacturing a three-dimensional manufactured object allowing for manufacturing such a three-dimensional manufactured object without spoiling the advantages possessed by the additive manufacturing method.SOLUTION: A method of manufacturing a three-dimensional manufactured object includes: a powder layer forming step of forming a powder layer by leveling an Fe-based metal powder; a binder providing step of providing a binder solution to a forming area of the powder layer corresponding to an additive manufactured body to be formed; an ink providing step of providing an ink containing carbon particles to the forming area such that the amount of a carbon particles to be supplied to the forming area is partially different; a repetition step of obtaining an additive manufactured body in which a plurality of unit layers is stacked provided that the forming area to which the binder solution and the ink are provided is considered as a unit layer; a sintering step of obtaining a metal sintered body by performing sintering processing on the additive manufactured body; and a hardening step of obtaining a three-dimensional manufactured object by performing hardening processing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a three-dimensional object and a three-dimensional object. [Background technology]

[0002] In recent years, additive manufacturing using metal powder has become increasingly popular as a technique for creating three-dimensional objects. This technology involves the steps of calculating the cross-sectional shape of the three-dimensional object when it is thinly sliced ​​along a plane perpendicular to the stacking direction, smoothing the metal powder into layers to form powder layers, and solidifying a portion of the powder layer based on the calculated shape. The three-dimensional object is created by repeating the steps of forming the powder layer and solidifying the portion.

[0003] For example, Patent Document 1 discloses a method for manufacturing a three-dimensional object, in which a layer formation step of forming a layer of granulated powder and a binder application step of applying a binder to this layer to form a shape are repeated to obtain a green body, and then the obtained green body is sintered to obtain a sintered body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-066139 Summary of the Invention [Problem to be solved by the invention]

[0005] The method described in Patent Document 1 has the following problems. For example, when a metal powder with a high carbon content is used, the toughness of the three-dimensionally shaped object decreases. As a result, the durability of the three-dimensionally shaped object tends to decrease.

[0006] Another known method involves producing a three-dimensional object using a metal powder with a low carbon content, and then subjecting the surface of the three-dimensional object to a carburizing treatment. This method allows for surface hardening while maintaining a low carbon content inside the three-dimensional object. However, this method requires an additional carburizing treatment after the production of the three-dimensional object, which compromises the advantages of additive manufacturing, such as simplicity and low cost.

[0007] Therefore, the challenge is to realize a method for manufacturing a three-dimensional object that combines high toughness and high surface hardness without losing the advantages of additive manufacturing. [Means for solving the problem]

[0008] A method for manufacturing a three-dimensional object according to an application example of the present invention includes: a powder layer forming step of leveling the Fe-based metal powder on a table to form a powder layer; a binder application step of applying a binder solution containing a binder to a formation region of the powder layer corresponding to a layered object to be formed; an ink applying step of applying ink containing the carbon particles to the formation region so that the amount of carbon particles supplied to the formation region varies partially; a repeating step of repeating the powder layer forming step, the binder applying step, and the ink applying step one or more times, where the formation region to which the binder solution and the ink have been applied is defined as a unit layer, to obtain the layered object in which a plurality of the unit layers are stacked; a sintering step of sintering the layered manufactured body to obtain a metal sintered body; a quenching step of quenching the metal sintered body to obtain a three-dimensional object; The present invention is characterized by having the following.

[0009] A method for manufacturing a three-dimensional object according to an application example of the present invention includes: a powder layer forming step of leveling the Fe-based metal powder on a table to form a powder layer; an ink impregnation step of impregnating a formation region of the powder layer corresponding to a metal sintered body to be formed with ink containing the carbon particles so that the amount of carbon particles supplied varies locally to obtain an ink-impregnated layer; an energy beam irradiation step of irradiating the formation region including at least the ink-impregnated layer with an energy beam to obtain a sintered layer; a repeating step of repeating the powder layer forming step, the ink impregnation step, and the energy ray irradiation step one or more times to obtain the metal sintered body in which a plurality of the sintered layers are stacked; a quenching step of quenching the metal sintered body to obtain a three-dimensional object; The present invention is characterized by having the following. [Brief explanation of the drawings]

[0011] [Figure 1] 2A to 2C are process diagrams illustrating the method for manufacturing a three-dimensional object according to the first embodiment. [Figure 2] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 3] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 4] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 5] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 6] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 7] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 8] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 9] FIG. 2 is a plan view for explaining a method for manufacturing the three-dimensional structure shown in FIG. [Figure 10] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 11]2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 12] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 13] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 14] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 15] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 16] 2A to 2C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. [Figure 17] 10A to 10C are process diagrams illustrating a method for manufacturing a three-dimensional object according to a second embodiment. [Figure 18] 18A to 18C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. 17. [Figure 19] 18A to 18C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. 17. [Figure 20] 18A to 18C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. 17. [Figure 21] 18A to 18C are cross-sectional views illustrating a method for manufacturing the three-dimensional structure shown in FIG. 17. [Figure 22] FIG. 10 is a cross-sectional view schematically showing the distribution of carbon concentration in a three-dimensionally shaped object according to a third embodiment. [Figure 23] FIG. 10 is a top view schematically showing the distribution of carbon concentration in a three-dimensionally shaped object according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the method for producing a three-dimensional structure and the three-dimensional structure according to the present invention will now be described in detail with reference to the accompanying drawings.

[0013] 1. First embodiment First, a method for manufacturing a three-dimensional object according to the first embodiment will be described.

[0014] FIG. 1 is a process diagram illustrating a method for manufacturing a three-dimensional object according to the first embodiment. FIGS. 2 to 8 are cross-sectional views illustrating a method for manufacturing the three-dimensional object shown in FIG. 1. FIG. 9 is a plan view illustrating a method for manufacturing the three-dimensional object shown in FIG. 1. FIGS. 10 to 16 are cross-sectional views illustrating a method for manufacturing the three-dimensional object shown in FIG. 1. In each drawing of the present application, an X-axis, a Y-axis, and a Z-axis are defined as three mutually orthogonal axes. Each axis is represented by an arrow, with the tip end side being the "plus side" and the base end side being the "minus side." In the following description, the plus side of the Z-axis will be referred to as "up" and the minus side of the Z-axis will be referred to as "down." Furthermore, both directions parallel to the X-axis will be referred to as X-axis directions, both directions parallel to the Y-axis will be referred to as Y-axis directions, and both directions parallel to the Z-axis will be referred to as Z-axis directions.

[0015] The method for manufacturing a three-dimensional object according to the first embodiment is a method called a binder jet method, and as shown in FIG. 1, includes a powder layer forming step S102, a binder applying step S104, an ink applying step S106, a repeating step S108, a sintering step S110, and a hardening step S112.

[0016] In the powder layer forming step S102, the Fe-based metal powder 1 is leveled on the building stage 23 (on the table) to form a powder layer 31. In the binder applying step S104, a binder solution 4 is applied to a formation region 60 of the powder layer 31 that corresponds to the layered object 6 to be built. In the ink applying step S106, an ink 5 containing carbon particles is applied to the formation region 60 of the powder layer 31. In the repeating step S108, the powder layer forming step S102, the binder applying step S104, and the ink applying step S106 are repeated one or more times. As a result, when the formation region 60 to which the binder solution 4 and the ink 5 are applied is defined as an ink-applied layer 51 (unit layer), multiple ink-applied layers 51 are stacked to obtain a layered object 6. In the sintering step S110, the layered object 6 is sintered to obtain a metal sintered body. In the quenching step S112, the metal sintered body is quenched to obtain a three-dimensional structure 10. Each step will be described below in order.

[0017] 1.1. Additive manufacturing equipment First, an additive manufacturing apparatus 2 will be described as an example of an apparatus used in the method for manufacturing a three-dimensional object according to the first embodiment.

[0018] The additive manufacturing device 2 comprises an apparatus main body 21 having a powder storage section 211 and a manufacturing section 212, a powder supply elevator 22 provided in the powder storage section 211, a manufacturing stage 23 provided in the manufacturing section 212, and a coater 24, a roller 25 and a liquid supply section 26 movably provided on the apparatus main body 21.

[0019] The powder storage section 211 is a recessed section that is provided in the device main body 21 and is open at the top. The Fe-based metal powder 1 is stored in the powder storage section 211. An appropriate amount of the Fe-based metal powder 1 stored in the powder storage section 211 is supplied to the modeling section 212 by the coater 24.

[0020] A powder feed elevator 22 is disposed at the bottom of the powder storage section 211. The powder feed elevator 22 is movable in the Z-axis direction with the Fe-based metal powder 1 loaded thereon. By moving the powder feed elevator 22 upward, the Fe-based metal powder 1 loaded on the powder feed elevator 22 is pushed up and caused to overflow from the powder storage section 211. As a result, the overflowing Fe-based metal powder 1 can be moved by the coater 24 toward the modeling section 212.

[0021] The shaping unit 212 is provided in the apparatus main body 21 and is a recessed portion that is open at the top. A shaping stage 23 is arranged inside the shaping unit 212. The Fe-based metal powder 1 is leveled and laid out in a layer on the shaping stage 23 by a coater 24. The shaping stage 23 is movable in the Z-axis direction with the Fe-based metal powder 1 laid out. The amount of the Fe-based metal powder 1 laid out on the shaping stage 23 can be adjusted by appropriately setting the height of the shaping stage 23.

[0022] The coater 24 and roller 25 are movable in the X-axis direction from the powder storage section 211 to the modeling section 212. The coater 24 drags the Fe-based metal powder 1, thereby leveling the Fe-based metal powder 1 and spreading it in a layer. The roller 25 compresses the leveled Fe-based metal powder 1 from above.

[0023] The liquid supply unit 26 is composed of, for example, an inkjet head or a dispenser, and is movable in the X-axis and Y-axis directions in the modeling unit 212. The liquid supply unit 26 can supply a desired amount of binder solution 4 or ink 5 to a desired position. Note that the liquid supply unit 26 may be provided with multiple ejection nozzles in one head. The binder solution 4 may be ejected from one protruding nozzle, and the ink 5 may be ejected from another ejection nozzle. The head that supplies the binder solution 4 and the head that supplies the ink 5 may be separate.

[0024] 1.2. Powder layer formation process In the powder layer forming step S102, the Fe-based metal powder 1 is spread on the building stage 23 to form a powder layer 31. Specifically, as shown in FIGS. 2 and 3, a coater 24 is used to drag the Fe-based metal powder 1 stored in the powder storage section 211 onto the building stage 23 and smooth it to a uniform thickness. This results in the powder layer 31 shown in FIG. 4. At this time, the upper surface of the building stage 23 is lowered below the upper end of the building section 212, and the thickness of the powder layer 31 can be adjusted by adjusting the amount of lowering.

[0025] Next, the roller 25 compresses the powder layer 31 in the thickness direction while moving the roller 25 in the X-axis direction. This increases the packing rate of the Fe-based metal powder 1 in the powder layer 31. Compression by the roller 25 may be performed as needed and may be omitted. Alternatively, the powder layer 31 may be compressed by a means other than the roller 25, such as a pressure plate.

[0026] The constituent material of the Fe-based metal powder 1 is not particularly limited as long as it is a metal material containing Fe as a main component, but examples thereof include Fe-based metal materials that can be expected to have improved hardness by adding carbon particles and performing a quenching treatment. The Fe-based metal material is not particularly limited, and examples thereof include stainless steel, steel for machine construction, tool steel, high-speed steel, die steel, bearing steel, and alloy steel.

[0027] Furthermore, the surface of the Fe-based metal powder 1 may be subjected to any surface treatment, such as treatment with a silane coupling agent, if necessary.

[0028] The method for producing the Fe-based metal powder 1 is not particularly limited, and examples include various atomization methods such as water atomization and gas atomization, and pulverization. Powders produced by water atomization often have an oxide film on the particle surface. This oxide film reacts with carbon particles and is reduced during a sintering process, which will be described later. Therefore, when using an Fe-based metal powder 1 with an oxide film, the amount of carbon particles contained in the ink 5, which will be described later, or the amount of ink 5 supplied to the formation region 60 may be adjusted in consideration of the consumption of carbon particles due to this reduction.

[0029] 1.3. Binder application process In the binder application step S104, as shown in FIG. 5, the liquid supply unit 26 supplies the binder solution 4 to a formation region 60 of the powder layer 31 that corresponds to the layered object 6 to be formed. The binder solution 4 is a liquid containing a binder and a solvent or dispersion medium. In the formation region 60 to which the binder solution 4 is supplied, the particles of the Fe-based metal powder 1 are bound together, resulting in a bonded layer 41 as shown in FIG. 6. In the bonded layer 41, the particles of the Fe-based metal powder 1 are bound together by the binder, and the bonded layer 41 has enough shape retention to prevent it from breaking under its own weight.

[0030] The binder layer 41 may be heated simultaneously with or after the supply of the binder solution 4. This promotes evaporation of the solvent or dispersion medium contained in the binder solution 4 and promotes the bonding of particles together due to solidification or hardening of the binder. When the binder contains a photocurable resin or an ultraviolet-curable resin, light irradiation or ultraviolet irradiation may be performed instead of or in addition to heating.

[0031] The heating temperature is not particularly limited, but is preferably 50° C. or higher and 250° C. or lower, and more preferably 70° C. or higher and 200° C. or lower. This makes it possible to prevent the Fe-based metal powder 1 from being degraded by heating when the Fe-based metal powder 1 that has not been bound by the binder solution 4 is reused.

[0032] The binder solution 4 is not particularly limited as long as it is a liquid containing components capable of binding together particles of the Fe-based metal powder 1. Examples of solvents or dispersion media contained in the binder solution 4 include water, alcohols, ketones, and carboxylic acid esters, and the binder solution 4 may be a mixture containing at least one of these. Examples of binders contained in the binder solution 4 include fatty acids, paraffin wax, microcrystalline wax, polyethylene, polypropylene, polystyrene, acrylic resins, polyamide resins, polyesters, stearic acid, polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), and polyethylene glycol (PEG).

[0033] 1.4.Ink application process In the ink application step S106, ink 5 is supplied to the formation region 60 of the powder layer 31. The ink 5 is a liquid containing carbon particles and a dispersion medium. In this embodiment, ink 5 is supplied to the binder layer 41 shown in FIG. 7, which corresponds to the formation region 60. This allows the binder layer 41 to be impregnated with the ink 5. As a result, carbon particles are applied to the binder layer 41, resulting in an ink-application layer 51 (unit layer) shown in FIG. 8. At this time, the amount of carbon particles supplied to the binder layer 41 is varied in different parts. The amount of carbon particles affects the hardness of the quenched structure in the quenching process described below. A quenched structure resulting from martensitic transformation exhibits high hardness and exhibits properties such as wear resistance. On the other hand, a quenched structure may result in a decrease in toughness. Therefore, by creating a quenched structure with locally adjusted hardness only in necessary areas, a three-dimensional object 10 that ultimately achieves both high toughness and high hardness can be obtained.

[0034] In this embodiment, as shown in FIG. 8 , a gradient is formed in which the amount of carbon particles decreases from the outer edge of the ink layer 51 toward the interior (portions other than the outer edge). FIG. 8 is a partial enlarged view of the ink layer 51 shown in FIG. 7 . In FIG. 8 , the gradient of the amount of carbon particles, in other words, the gradient of the carbon particle concentration, is represented by the slope of the arrow C1. In the example of FIG. 8 , the arrow C1 is sloped so that the amount is lower at the interior of the ink layer 51 than at the outer edge. By providing such a concentration gradient, a three-dimensionally shaped object 10 having high surface hardness and high internal toughness is ultimately obtained. Note that the concentration gradient may be smooth (a gradient with a continuously changing slope) or step-like (a gradient with a discontinuously changing slope). It is sufficient that there is a gradient macroscopically overall, and in consideration of decarbonization during sintering, there may be some areas near the surface where the concentration is high. Furthermore, in this process, the pattern of the supplied carbon particles is not particularly limited, as long as the amount of carbon particles varies locally. For example, part of the formation region 60 may include a region where no ink 5 is supplied (a region where the amount of carbon particles supplied is zero).

[0035] FIG. 9 is a plan view of the ink layer 51 shown in FIG. 8. In FIG. 9, the gradient of the carbon particle concentration is represented by the density of dots. In the example of FIG. 9, the outer edge of the ink layer 51 is circular, and the concentration of carbon particles increases radially from the center toward the outer edge. The concentration gradient pattern is not limited to the pattern shown. For example, the concentration gradient may be steeper or gentler in a portion of the outer edge compared to other portions. Furthermore, the binder application step S104 and the ink application step S106 may be performed in reverse order. That is, after the ink 5 is applied to the formation region 60, the binder solution 4 may be applied, and this may form the ink layer 5 (unit layer).

[0036] Carbon particles are particles composed of a material containing elemental carbon as the main component, and examples thereof include graphite particles, carbon black, carbon fiber, and carbon nanotubes. The term "main component" refers to a component that accounts for 50.0% by mass or more. Preferably, the carbon particles are particles composed of 90.0% by mass or more of elemental carbon.

[0037] The carbon particles are preferably carbon black. Carbon black is an industrially produced carbon powder with uniform surface properties, such as the presence of various functional groups on the particle surface. Therefore, ink 5 containing carbon black as the carbon powder has excellent stability and allows the carbon particles to be supplied so as to be uniformly distributed.

[0038] The average particle size of the carbon particles is preferably 1 / 100,000 to 1 / 100 of the average particle size of the Fe-based metal powder 1, more preferably 1 / 50,000 to 1 / 500, and even more preferably 1 / 10,000 to 1 / 1000. This allows the carbon particles to easily penetrate into the gaps between the particles of the Fe-based metal powder 1, and therefore when the ink 5 is supplied to the formation region 60, the carbon particles can be easily distributed along the surfaces of the particles of the Fe-based metal powder 1. As a result, the quenching process described below can be performed more uniformly.

[0039] The average particle size of the carbon particles is preferably 10 nm or more and 10 μm or less, and more preferably 10 nm or more and 5 μm or less. The average particle size of the carbon particles refers to the particle size at which the cumulative mass based on volume is 50% as measured using a laser diffraction particle size distribution analyzer. In addition, carbon particles may aggregate together in the ink 5 to form secondary particles. In this case, the particle size of the secondary particles is taken as the particle size of the carbon particles.

[0040] Examples of the dispersion medium include water, organic solvents, mixtures of water and organic solvents, etc. Among these, examples of water include ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, pure water, ultrapure water, etc. Examples of the organic solvent include water-soluble solvents and water-insoluble solvents.

[0041] The carbon particle content of the ink 5 is appropriately set depending on the ink supply method, but is preferably 0.1% by mass or more and 50.0% by mass or less, more preferably 1.0% by mass or more and 30.0% by mass or less, even more preferably 2.0% by mass or more and 20.0% by mass or less, and particularly preferably 5.0% by mass or more and 20.0% by mass or less. By setting the carbon particle content of the ink 5 within the above range, it is possible to achieve both ease of handling of the ink 5 and efficient supply of the carbon particles. If the carbon particle content of the ink 5 is below the lower limit, supply efficiency decreases, making it necessary to supply a large amount of ink 5 to the formation region 60, which may reduce the mechanical strength of the ink-giving layer 5. If the carbon particle content of the ink 5 exceeds the upper limit, the viscosity of the ink 5 becomes too high, which may reduce the handleability of the ink 5 depending on the supply method.

[0042] Additives other than the above components may be added to the ink 5. Examples of additives include dispersants, surfactants, wetting agents (anti-drying agents), antioxidants, UV absorbers, penetration enhancers, preservatives, anti-fungal agents, pH adjusters, viscosity adjusters, and chelating agents.

[0043] 1.5.Repetitive process In the repeating step S108, when the formation region 60 to which the binder solution 4 and the ink 5 are applied is designated as an ink-application layer 51 (unit layer), the powder layer forming step S102, the binder application step S104, and the ink application step S106 are repeated one or more times until a laminate formed by stacking a plurality of these ink-application layers 51 assumes a predetermined shape. In other words, these steps are performed a total of two or more times. This results in a three-dimensional layered object 6 shown in FIG. 15.

[0044] Specifically, first, as shown in Fig. 10, a new powder layer 31 is formed on the ink application layer 51 shown in Fig. 8. Next, as shown in Fig. 11, a binder solution 4 is supplied to a formation region 60 of the powder layer 31. This results in a binder layer 41 shown in Fig. 12.

[0045] Next, ink 5 is supplied to the formation region 60 of the powder layer 31. In this embodiment, ink 5 is supplied to the binder layer 41 shown in FIG. 12. This results in the ink application layer 51 shown in FIG. 13. FIG. 14 is a partial enlarged view of the ink application layer 51 shown in FIG. 13. In FIG. 14, the gradient of the concentration of carbon particles is represented by the inclination of the arrow C2. In the example of FIG. 14, the arrow C2 is also inclined so that the concentration is lower at the inside of the ink application layer 51 than at the outer edge.

[0046] The inclination of the arrow C2 shown in Fig. 14 may be the same as the inclination of the arrow C1 shown in Fig. 8, but it is preferable that they are different from each other. This makes it possible to optimize the concentration gradient of the carbon particles depending on the shape of the three-dimensionally shaped object 10.

[0047] As described above, the layered object 6 shown in FIG. 15 is a laminate of a plurality of ink-applied layers 51 (unit layers). Of the powder layers 31, the Fe-based metal powder 1 that does not constitute the ink-applied layer 51 is collected and reused as necessary. When repeating step S108 two or more times, the application of ink 5 may be omitted in some of the repeating steps S108. Furthermore, when repeating step S108 two or more times, the amount of carbon particles supplied to the formation region 60 may not be partially different in some of the repeating steps S108.

[0048] 1.6.Sintering process In the sintering step S110, a sintering process is performed on the layered manufactured body 6. In the sintering process, the layered manufactured body 6 is heated to cause a sintering reaction, thereby obtaining a metal sintered body.

[0049] The sintering temperature varies depending on the type and particle size of the Fe-based metal powder 1, but is preferably 980° C. to 1330° C., and more preferably 1050° C. to 1260° C. The sintering time is preferably 0.2 hours to 7 hours, and more preferably 1 hour to 6 hours.

[0050] The atmosphere for the sintering treatment may be, for example, a reducing atmosphere such as hydrogen, an inert atmosphere such as nitrogen or argon, or a reduced pressure atmosphere obtained by reducing the pressure of these atmospheres. The pressure of the reduced pressure atmosphere is not particularly limited as long as it is less than normal pressure (100 kPa), but is preferably 10 kPa or less, and more preferably 1 kPa or less.

[0051] 1.7.Quenching process In the quenching step S112, the metal sintered body is quenched. The quenching process involves heating the metal sintered body and then rapidly cooling it. As a result, in areas where the carbon concentration has been increased to a predetermined concentration, the metal structure transforms from austenite to martensite, resulting in a quenched structure derived from martensite, which provides high hardness. This process of changing to a quenched structure is called "quenching." On the other hand, in areas where the carbon concentration is not increased, no quenched structure is formed, and therefore no increase in hardness occurs. This quenching process results in a three-dimensional structure 10 shown in FIG. 16.

[0052] The quenching temperature is, for example, 950° C. to 1200° C. The quenching time is, for example, 0.2 hours to 3 hours. For the rapid cooling, water cooling, oil cooling, or the like is used.

[0053] After the quenching treatment, a tempering treatment may be performed as necessary. The tempering treatment is a treatment in which the quenched metal sintered body is heated again at a lower temperature than that used in the quenching treatment. This treatment can slightly reduce the hardness of the metal sintered body while imparting toughness.

[0054] The tempering temperature is, for example, 100° C. or more and 250° C. or less, and the tempering time is, for example, 0.3 hours or more and 5 hours or less.

[0055] 1.8. Advantages of the First Embodiment As described above, the method for manufacturing a three-dimensionally shaped object according to the first embodiment includes the powder layer forming step S102, the binder applying step S104, the ink applying step S106, the repeating step S108, the sintering step S110, and the quenching step S112. In the powder layer forming step S102, the Fe-based metal powder 1 is leveled on the building stage 23 (on the table) to form the powder layer 31. In the binder applying step S104, a binder solution 4 containing a binder is applied to a formation region 60 of the powder layer 31 that corresponds to the layered object 6 to be formed. In the ink applying step S106, an ink 5 containing carbon particles is applied to the formation region 60 so that the amount of carbon particles supplied to the formation region 60 varies from region to region. In the repeating step S108, when the formation region 60 to which the binder solution 4 and the ink 5 are applied is designated as an ink-application layer 51 (unit layer), the powder layer forming step S102, the binder application step S104, and the ink application step S106 are repeated one or more times to obtain a layered object 6 in which multiple ink-application layers 51 are stacked. In the sintering step S110, the layered object 6 is sintered to obtain a metal sintered body. In the quenching step S112, the metal sintered body is quenched to obtain a three-dimensionally shaped object 10.

[0056] According to this configuration, by partially varying the amount of carbon particles supplied to the formation region 60, the degree of hardening in the finally obtained three-dimensional structure 10, i.e., the hardness of the hardened structure, can be partially varied. As a result, for example, the degree of hardening can be increased near the surface of the three-dimensional structure 10, thereby increasing hardness, while the degree of hardening can be decreased in the interior of the three-dimensional structure 10, thereby suppressing an increase in hardness. As a result, a three-dimensional structure 10 having high surface hardness and high internal toughness can be realized. Such a three-dimensional structure 10 has both high toughness and high hardness, and therefore, for example, both wear resistance and durability can be achieved.

[0057] Furthermore, the above method allows the advantages of the binder jet method, which is an additive manufacturing method, to be enjoyed without compromising them. For example, it is possible to set an area having an internal cavity as the formation area 60. This makes it easy to form a hollow structure, which allows the formation area 60 to be lightweight, ultimately resulting in a three-dimensional object 10 with high surface hardness and a lightweight structure.

[0058] Furthermore, in the method for manufacturing a three-dimensional object according to the first embodiment, ink 5 is applied so that the amount of carbon particles supplied to the outer edge of the formation region 60 is greater than the amount of carbon particles supplied to areas other than the outer edge of the formation region 60.

[0059] The formation area 60 obtained in this manner is used to form the layered object 6, and finally a three-dimensional object 10 is obtained, thereby efficiently producing a three-dimensional object 10 with high surface hardness and high internal toughness.

[0060] Furthermore, by providing a gradient in which the concentration of carbon particles changes continuously, it is possible to prevent cracks and the like from occurring due to the difference in thermal expansion between the hardened structure layer near the surface and the internal metal structure in the three-dimensional object 10. This improves the reliability of the three-dimensional object 10.

[0061] Furthermore, when the ink application layers 51 (unit layers) are laminated together in the repeating step S108, the amount of carbon particles may be made different between the ink application layers 51. For example, in Fig. 14, the slope of the arrow C1 representing the gradient of the concentration of carbon particles in the first ink application layer 51 is different from the slope of the arrow C2 representing the gradient of the concentration of carbon particles in the second ink application layer 51. This corresponds to making the amount of carbon particles different between the ink application layers 51.

[0062] With this configuration, the amount of carbon particles to be supplied can be optimized depending on the shape of the three-dimensionally molded object 10. This allows the thickness of the highly hardened layer to be optimized depending on the shape of the three-dimensionally molded object 10, thereby optimizing the balance between high hardness and high toughness of the three-dimensionally molded object 10.

[0063] When applying the ink 5, the amount of carbon particles supplied is adjusted so that the carbon concentration in the three-dimensional structure 10 is preferably 0.2% by mass or more, and more preferably 0.3% by mass or more and 2.2% by mass or less.

[0064] This configuration allows for more reliable hardening through the hardening process. Note that the carbon concentration immediately after supplying the ink 5 may decrease during subsequent processes. Therefore, it is preferable to set the amount of carbon particles supplied by the ink 5 taking this decrease in concentration into consideration.

[0065] In addition, the ink application step S106 preferably includes an operation of partially varying the amount of carbon particles by changing the density of the droplets ejected per unit area when the ink 5 is ejected as droplets from a plurality of aligned nozzles, as shown in Figures 7 and 12.

[0066] When the ink 5 is ejected from the multiple nozzles of the liquid supply unit 26, it is easy and accurate to select the nozzle that ejects the ink 5. Therefore, the above operation makes it possible to easily and accurately control the amount of carbon particles supplied per unit area. As a result, it is possible to easily manufacture a three-dimensional object 10 that has a desired carbon concentration at a desired position.

[0067] In the binder application step S104 and the ink application step S106, the application of the binder solution 4 and the application of the ink 5 may be carried out almost simultaneously. In other words, the binder solution 4 and the ink 5 may be ejected almost simultaneously from the same head or different heads. This can increase the throughput of the binder application step S104 and the ink application step S106. "Almost simultaneously" means that the time difference between them is one second or less.

[0068] On the other hand, in consideration of the fact that the ejected binder solution 4 and ink 5 are mixed together, it is preferable to provide a time difference between the application of the binder solution 4 and the application of the ink 5.

[0069] Alternatively, the binder solution 4 and the ink 5 may be mixed to form a liquid mixture, which may then be ejected. That is, the binder application step S104 and the ink application step S106 may be performed simultaneously by applying a liquid containing both the binder and carbon particles to the formation region 60. This allows the throughput of the binder application step S104 and the ink application step S106 to be increased.

[0070] The sintering process and the quenching process may be performed in different processing devices, or may be performed in a single processing device. In other words, after the sintering process is completed, the layered product 6 may be left in the processing device, so that the sintering process and the quenching process can be performed consecutively without lowering the temperature of the layered product 6 to room temperature (25°C).

[0071] According to this configuration, the sintering step S110 and the quenching step S112 can be carried out consecutively, thereby increasing the throughput of these steps.

[0072] The powder layer forming step S102 may also include compressing the powder layer 31 in the thickness direction. This operation can increase the packing rate of the Fe-based metal powder 1 in the powder layer 31. This can ultimately increase the density of the three-dimensionally shaped object 10, even when an Fe-based metal powder 1 with a high bulk density is used.

[0073] 2. Second embodiment Next, a method for manufacturing a three-dimensional object according to the second embodiment will be described.

[0074] Fig. 17 is a process diagram illustrating a method for manufacturing a three-dimensional object according to the second embodiment. Fig. 18 to Fig. 21 are cross-sectional views illustrating the method for manufacturing the three-dimensional object shown in Fig. 17.

[0075] The second embodiment will be described below, focusing on the differences from the first embodiment and omitting the description of the similarities. In each drawing, the same reference numerals are used to designate the same components as those in the first embodiment.

[0076] The method for manufacturing a three-dimensional object according to the second embodiment is a method called selective laser sintering (SLS) method, and as shown in FIG. 17, includes a powder layer forming step S202, an ink impregnation step S204, an energy beam irradiation step S206, a repeating step S208, and a hardening step S210.

[0077] 2.1. Additive manufacturing equipment First, a layered manufacturing apparatus 2A will be described as an example of an apparatus used in a method for manufacturing a three-dimensional object according to the second embodiment.

[0078] The layered manufacturing apparatus 2A is similar to the layered manufacturing apparatus 2 described above, except that an energy beam irradiation unit 27 is added.

[0079] 19, the energy beam irradiation unit 27 is capable of irradiating an energy beam E to any position on the modeling stage 23. Examples of the energy beam E include a laser beam and an electron beam. The irradiation of the energy beam E causes a sintering reaction between particles of the Fe-based metal powder 1.

[0080] 2.2. Powder layer formation process In the powder layer forming step S202, similarly to the powder layer forming step S102 in the first embodiment, the Fe-based metal powder 1 is leveled on the manufacturing stage 23 (on the table) to form the powder layer 31.

[0081] 2.3.Ink impregnation process In the ink impregnation step S204, ink 5 is supplied to a formation region 60 of the powder layer 31 that corresponds to the metal sintered body 7 to be formed. This allows the formation region 60 to be impregnated with ink 5. As a result, the ink-impregnated layer 52 shown in FIG. 19 is obtained. At this time, the amount of carbon particles supplied to the formation region 60 is made to vary depending on the region. Specifically, similar to the concentration gradient indicated by arrow C1 in FIG. 8, a gradient of carbon particle concentration is set so that the concentration is lower at the inside of the ink-impregnated layer 52 than at the outer edge. This ultimately results in a three-dimensional object 10 with high surface hardness and high internal toughness. Note that there may be regions in the formation region 60 where no ink 5 is supplied (regions where no amount of carbon particles is supplied).

[0082] The average particle size of the carbon particles is preferably 1 / 100,000 to 1 / 100 of the average particle size of the Fe-based metal powder 1, more preferably 1 / 50,000 to 1 / 500, and even more preferably 1 / 10,000 to 1 / 1000. This allows the carbon particles to easily penetrate into the gaps between the particles of the Fe-based metal powder 1, and therefore when the ink 5 is supplied to the formation region 60, the carbon particles can be easily distributed along the surfaces of the particles of the Fe-based metal powder 1. As a result, the quenching process described below can be performed more uniformly.

[0083] 2.4. Energy ray irradiation process In the energy beam irradiation step S206, as shown in Fig. 19, the energy beam irradiation unit 27 irradiates the formation region 60 including at least the ink-impregnated layer 52 with energy beams E. In the ink-impregnated layer 52 irradiated with the energy beams E, the particles of the Fe-based metal powder 1 are sintered together, resulting in a sintered layer 71 shown in Fig. 20. In the sintered layer 71, the particles of the Fe-based metal powder 1 are sintered together to form a metal sintered body.

[0084] 2.5.Repetitive process In the repeating step S208, the powder layer forming step S202, the ink impregnation step S204, and the energy ray irradiation step S206 are repeated one or more times until a laminate formed by stacking a plurality of sintered layers 71 has a predetermined shape, thereby obtaining a three-dimensional metal sintered body 7 shown in FIG.

[0085] 2.6.Quenching process In the quenching step S210, the metal sintered compact 7 is quenched, similarly to the quenching step S112 in the first embodiment. As a result, the three-dimensional structure 10 shown in FIG. 16 is obtained. In the second embodiment, since the energy supplied by the energy beam E is high, the quenching may be completed at the same time as the energy beam irradiation step S206 is completed. In this case, this step may be omitted, or this step may be performed and then a re-quenching treatment may be performed. Furthermore, similarly to the first embodiment, a tempering treatment may be performed after the quenching treatment.

[0086] 2.7. Advantages of the Second Embodiment As described above, the method for manufacturing a three-dimensionally shaped object according to the second embodiment includes the powder layer forming step S202, the ink impregnation step S204, the energy beam irradiation step S206, the repeating step S208, and the quenching step S210. In the powder layer forming step S202, the Fe-based metal powder 1 is leveled on the building stage 23 (on the table) to form the powder layer 31. In the ink impregnation step S204, the powder layer 31 is impregnated with ink 5 containing carbon particles so that the amount of carbon particles supplied varies from part to part in the formation region 60 corresponding to the metal sintered body 7 to be formed, thereby obtaining an ink-impregnated layer 52. In the energy beam irradiation step S206, the formation region 60 including at least the ink-impregnated layer 52 is irradiated with energy beams E to obtain a sintered layer 71. In the repeating step S208, the powder layer forming step S202, the ink impregnation step S204, and the energy ray irradiation step S206 are repeated one or more times to obtain a metal sintered body 7 having a plurality of stacked sintered layers 71. In the quenching step S210, the metal sintered body 7 is quenched to obtain a three-dimensionally shaped object 10.

[0087] According to this configuration, by partially varying the amount of carbon particles supplied to the formation region 60, the degree of hardening in the finally obtained three-dimensional structure 10, i.e., the hardness of the hardened structure, can be partially varied. As a result, for example, the degree of hardening can be increased near the surface of the three-dimensional structure 10, thereby increasing hardness, while the degree of hardening can be decreased in the interior of the three-dimensional structure 10, thereby suppressing an increase in hardness. As a result, a three-dimensional structure 10 having high surface hardness and high internal toughness can be realized. Such a three-dimensional structure 10 has both high toughness and high hardness, and therefore, for example, both wear resistance and durability can be achieved.

[0088] Furthermore, the above method allows the advantages of powder sintering additive manufacturing, which is an additive manufacturing method, to be enjoyed without compromising them. For this reason, for example, it is possible to set an area having an internal cavity as the formation area 60. This allows the formation area 60 to be made lighter, ultimately resulting in a lightweight three-dimensional object 10 with high surface hardness.

[0089] Furthermore, in the method for manufacturing a three-dimensional object according to the second embodiment, ink 5 is applied so that the amount of carbon particles supplied to the outer edge of the formation region 60 is greater than the amount of carbon particles supplied to areas other than the outer edge of the formation region 60.

[0090] The formation area 60 obtained in this manner is used to form a metal sintered body 7, and finally a three-dimensional object 10 is obtained, thereby making it possible to efficiently manufacture a three-dimensional object 10 having high surface hardness and high internal toughness.

[0091] Furthermore, by providing a gradient in which the concentration of carbon particles changes continuously, it is possible to prevent cracks and the like from occurring due to the difference in thermal expansion between the hardened structure layer near the surface and the internal metal structure in the three-dimensional object 10. This improves the reliability of the three-dimensional object 10.

[0092] 3. Third embodiment Next, a three-dimensional object according to a third embodiment will be described.

[0093] FIG. 22 is a cross-sectional view schematically showing the distribution of carbon concentration in the three-dimensional structure 10 according to the third embodiment.

[0094] The third embodiment will be described below, but the following description will focus on the differences from the first embodiment, and a description of similar points will be omitted.

[0095] In the three-dimensional structure 10 shown in FIG. 22, the carbon concentration is represented by the density of dots. The three-dimensional structure 10 is made of a sintered material of an Fe-based metal powder 1. The three-dimensional structure 10 has regions 19 in which the carbon concentration decreases from the outer surface 11 toward the interior 12. In this embodiment, the entire three-dimensional structure 10 is made of the regions 19, but it is also possible that only a portion of the three-dimensional structure 10 is made of the regions 19, with the remaining regions being made of a different structure. An example of such a different structure is a structure with a constant carbon concentration.

[0096] As described above, the three-dimensional shaped object 10, 10A according to this embodiment is made of a sintered material of the Fe-based metal powder 1, and has a region 19 in which the carbon concentration decreases from the outer surface 11 toward the interior 12.

[0097] With this configuration, it is possible to achieve both high hardness in the outer surface 11 and high toughness in the inner portion 12 .

[0098] Furthermore, as described above, it is preferable that the gradient of the carbon concentration decrease in the region 19 varies in intensity from region to region.

[0099] According to this configuration, when the region 19 has, for example, a locally tapered portion and an even thicker portion, it is possible to achieve both high hardness in the outer surface 11 and high toughness in the interior 12 in both portions. In other words, if the carbon concentration gradient is gentle in the tapered portion, the area of ​​the outer surface 11 becomes too thick, and the volume of the interior 12 becomes relatively small, making it difficult to achieve both high hardness and high toughness. Therefore, by making the carbon concentration gradient stronger in such a portion, it becomes easier to achieve both high hardness and high toughness.

[0100] The carbon concentration in the outer surface 11 is preferably 0.2 mass% or more, and more preferably 0.3 mass% or more and 2.2 mass% or less. If the carbon concentration is within this range, the metal structure of the outer surface 11 can be well hardened and structured. This makes it possible to more reliably harden the outer surface 11.

[0101] The carbon concentration on the outer surface 11 is measured by, for example, an electron probe microanalyzer (EPMA) method.

[0102] FIG. 23 is a top view schematically showing the distribution of carbon concentration in a three-dimensional structure 10A according to a modified example.

[0103] The three-dimensionally shaped object 10A shown in FIG. 23 is a spur gear having a plurality of external teeth 13 and a shaft hole 14. Each external tooth 13 has a tooth surface 15. The external teeth 13 mesh with the external teeth of another gear (not shown) to transmit rotation. Therefore, the tooth surface 15 rubs against the tooth surface of the other gear, causing wear. For this reason, the three-dimensionally shaped object 10A is configured so that the carbon concentration decreases from the tooth surface 15 toward its interior. In FIG. 23, the gradient of the carbon concentration on the tooth surface 15 is represented by the inclination of arrow C3.

[0104] The shaft hole 14 is configured so that the carbon concentration decreases from the inner surface 16 toward the interior. The gradient of the carbon concentration on the inner surface 16 of the shaft hole 14 is represented by the inclination of arrow C4. A shaft (not shown) is inserted into the shaft hole 14. For this reason, there is little friction between the surface of the shaft and the shaft.

[0105] Therefore, it is preferable that the inclination of arrow C3 is steeper than the inclination of arrow C4. This allows the tooth flank 15 to have a higher hardness than the inner surface 16. On the other hand, the inner surface 16 can have a higher toughness than the tooth flank 15. Therefore, with the three-dimensionally shaped object 10A according to this modification, it is possible to realize a gear that has excellent wear resistance of the tooth flank 15 and durability of the shaft hole 14, and that achieves a long life.

[0106] When producing the above-described three-dimensional structure 10A, the ink 5 may be applied so that the gradient in the amount of carbon particles decreasing from the outer edge toward the inside of the formation region 60 shown in FIG. 8 varies in intensity. That is, the gradient of arrow C3 representing the gradient of the carbon concentration on the tooth surface 15 may be made different from the gradient of arrow C4 representing the gradient of the carbon concentration on the inner surface 16. As shown in FIG. 23, arrow C3 represents the gradient of the carbon concentration in a cross section that intersects the tooth surface 15 and connects points D1 and D2. Arrow C4 represents the gradient of the carbon concentration in a cross section that intersects the inner surface 16 and connects points D3 and D4.

[0107] With this configuration, when the three-dimensionally shaped object 10A thus produced is applied to a gear, it is possible to increase the hardness of the tooth surface 15 while simultaneously increasing the toughness of the inner surface 16 of the shaft hole 14. As a result, it is possible to easily realize a gear that has a long life.

[0108] The above-described three-dimensional objects 10 and 10A can be used as, for example, all or part of transportation equipment parts such as automobile parts, bicycle parts, railway vehicle parts, ship parts, aircraft parts, and space transport parts; electronic equipment parts such as personal computer parts, mobile phone parts, tablet terminal parts, and wearable terminal parts; electrical equipment parts such as refrigerators, washing machines, and air conditioners; machine parts such as machine tools and semiconductor manufacturing equipment; plant parts such as nuclear power plants, thermal power plants, hydroelectric power plants, refineries, and chemical complexes; watch parts; and decorative items such as metal tableware, jewelry, and eyeglass frames.

[0109] The method for manufacturing a three-dimensional object and the three-dimensional object according to the present invention have been described above based on the illustrated embodiment. However, the present invention is not limited to this. For example, the three-dimensional object according to the present invention may be one in which any component is added to the above embodiment.

[0110] Furthermore, the method for producing a three-dimensional structure of the present invention may be configured by adding any step for any purpose to the above-described embodiment. [Explanation of symbols]

[0111] 1...Fe-based metal powder, 2...Layered manufacturing device, 2A...Layered manufacturing device, 4...Binder solution, 5...Ink, 6...Layered manufactured body, 7...Metal sintered body, 10...Three-dimensional manufactured object, 10A...Three-dimensional manufactured object, 11...Outer surface, 12...Interior, 13...External teeth, 14...Axial hole, 15...Tooth surface, 16...Interior, 19...Part, 21...Device body, 22...Powder supply elevator, 23...Modeling stage, 24...Coater, 25...Roller, 26...Liquid supply unit, 27...Energy beam irradiation unit, 31...Powder layer, 41...Binder layer, 51...Ink application layer, 52...Ink impregnation Layer, 60...forming region, 71...sintered layer, 211...powder storage section, 212...molding section, C1...arrow, C2...arrow, C3...arrow, C4...arrow, D1...point, D2...point, D3...point, D4...point, E...energy beam, S102...powder layer forming process, S104...binder application process, S106...ink application process, S108...repeating process, S110...sintering process, S112...quenching process, S202...powder layer forming process, S204...ink impregnation process, S206...energy beam irradiation process, S208...repeating process, S210...quenching process

Claims

1. a powder layer forming step of leveling the Fe-based metal powder on a table to form a powder layer; In the powder layer, a binder is applied to a formation region corresponding to a layered object to be formed. a binder application step of applying a binder solution containing The carbon particles are supplied to the forming region in such a manner that the amount of the carbon particles is partially different. an ink application step of applying ink to the formation region; When the formation area to which the binder solution and the ink are applied is defined as a unit layer, The powder layer forming step, the binder applying step, and the ink applying step are repeated one or more times. A repeating process for obtaining the layered object in which a plurality of the unit layers are stacked. The degree, a sintering step of sintering the layered manufactured body to obtain a metal sintered body; a quenching step of quenching the metal sintered body to obtain a three-dimensional object; A method for manufacturing a three-dimensional object, comprising:

2. The amount of the carbon particles supplied to the outer edge of the formation region is 2. The method of claim 1, wherein the ink is applied in an amount greater than the amount of the carbon particles supplied to the outside.

1. A method for producing a three-dimensional object according to claim 1.

3. The strength of the gradient in which the amount of carbon particles decreases from the outer edge toward the inside varies in part. The method for manufacturing a three-dimensional object according to claim 2 , wherein the ink is applied so as to form a three-dimensional object.

4. In the repeating step, when the unit layers are stacked, the formation regions are 4. The method for producing a three-dimensional structure according to claim 1, wherein the amount of carbon particles is varied. method.

5. The ink is applied so that the carbon concentration in the three-dimensional object is 0.2 mass % or more.

5. The amount of carbon particles supplied according to claim 1, wherein the amount of carbon particles supplied is adjusted by adding 2. A method for producing a three-dimensional object according to claim 1.

6. The average particle size of the carbon particles is 1 / 100,000 or more of the average particle size of the Fe-based metal powder. The method for manufacturing a three-dimensional object according to claim 1 , wherein the ratio of the surface roughness to the surface roughness is 1 / 100 or less.

7. The ink application step ejects the ink as droplets from a plurality of aligned nozzles. By changing the density of the droplets discharged per unit area, the amount of the carbon particles can be controlled.

7. The method for producing the three-dimensional object according to claim 1, further comprising the step of varying the surface roughness of the three-dimensional object. method.

8. applying a liquid containing both the binder and the carbon particles to the forming region; 10. The method of claim 1, wherein the binder application step and the ink application step are carried out simultaneously.

8. A method for producing a three-dimensional object according to any one of claims 7 to 7.

9. The sintering and quenching processes are performed without lowering the temperature of the layered manufactured body to room temperature. By performing the treatment continuously, the sintering step and the quenching step are performed continuously. The method for manufacturing a three-dimensional object according to any one of claims 1 to 8.

10. a powder layer forming step of leveling the Fe-based metal powder on a table to form a powder layer; The powder layer is supplied to a forming region corresponding to a metal sintered body to be formed. The ink containing the carbon particles is impregnated so that the amount of the carbon particles varies in parts. an ink impregnation step for obtaining an ink impregnated layer; The formation region including at least the ink impregnated layer is irradiated with energy rays to obtain a sintered layer. an energy ray irradiation step; The powder layer forming step, the ink impregnation step, and the energy ray irradiation step are repeated one or more times. a repeating step of repeating the above to obtain the metal sintered body in which a plurality of the sintered layers are stacked; a quenching step of quenching the metal sintered body to obtain a three-dimensional object; A method for manufacturing a three-dimensional object, comprising:

11. The amount of the carbon particles supplied to the outer edge of the formation region is 2. The method of claim 1, wherein the ink is applied in an amount greater than the amount of the carbon particles supplied to the outside.

10. The method for producing a three-dimensional object according to claim 0.

12. The average particle size of the carbon particles is 1 / 100,000 or more of the average particle size of the Fe-based metal powder. The method for producing a three-dimensional object according to claim 10 or 11, wherein the ratio of the surface roughness to the surface roughness is 1 / 100 or less.

13. 13. The method according to claim 1, further comprising compressing the powder layer in the thickness direction. A method for manufacturing three-dimensional objects.

Images