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

Abstract

This invention provides a method for manufacturing a three-dimensional object that achieves both high toughness and high hardness without compromising the advantages of the stacking molding method, as well as the three-dimensional object itself. The method comprises: a powder layer forming step, in which Fe-based metal powder is planarized to form a powder layer; a binder application step, in which a binder solution is applied to a forming region in the powder layer corresponding to the desired stacked shape; an ink application step, in which ink containing carbon particles is applied to the forming region in a manner that locally varies the amount of carbon particles supplied to the forming region; a repetition step, in which a stacked shape is obtained by stacking multiple unit layers, with the forming region to which the binder solution and ink are applied serving as a unit layer; a sintering step, in which the stacked shape is sintered to obtain a sintered metal body; and a quenching step, in which the stacked shape is quenched to obtain the three-dimensional object.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a three-dimensional object and the three-dimensional object itself. Background Technology

[0002] In recent years, the layering method using metal powder has become increasingly popular as a technique for shaping three-dimensional objects. This technique involves a process of calculating the cross-sectional shape of the object when it is sliced ​​into thin sheets using planes orthogonal to the layering direction; a process of flattening metal powder into layers to form powder layers; a process of curing a portion of the powder layer based on the calculated shape; and a technique of shaping the three-dimensional object by repeatedly performing the powder layer formation and curing processes.

[0003] For example, Patent Document 1 discloses a method for manufacturing a three-dimensional object, wherein the method involves repeatedly performing a layer forming process to form a layer of granulated powder and an adhesive application process to apply an adhesive to the layer to form a shape to obtain a live body, and then sintering the obtained live body to obtain a sintered body.

[0004] The method described in Patent Document 1 has the following drawback: For example, when using metal powder with a high carbon content, the toughness of the three-dimensional model decreases. Consequently, the durability of the three-dimensional model tends to decline.

[0005] Furthermore, a method for carburizing the surface of a three-dimensional model obtained using metal powder with a low carbon content is known. This method allows for surface hardening while maintaining a low carbon content within the three-dimensional model. However, because this method requires additional carburizing after the manufacture of the three-dimensional model, it compromises the advantages of the lamination method, such as simplicity and low cost.

[0006] Therefore, a method for manufacturing three-dimensional objects that combine high toughness and high surface hardness without compromising the advantages of the layered modeling method has become a research topic.

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-066139 Summary of the Invention

[0008] The method for manufacturing a three-dimensional model according to an application example of the present invention is characterized by comprising: a powder layer forming step, wherein Fe-based metal powder is flattened on a worktable to form a powder layer; a binder application step, wherein a binder solution containing binder is applied to a forming region in the powder layer corresponding to the desired layered model; an ink application step, wherein ink containing carbon particles is applied to the forming region in such a way that the amount of carbon particles supplied to the forming region is locally different; a repetition step, wherein when the forming region to which the binder solution and the ink are applied is set as a unit layer, the powder layer forming step, the binder application step, and the ink application step are repeated more than once to obtain a layered model formed by stacking multiple unit layers; a sintering step, wherein the layered model is sintered to obtain a sintered metal body; and a quenching step, wherein the sintered metal body is quenched to obtain a three-dimensional model.

[0009] The method for manufacturing a three-dimensional object according to an application example of the present invention is characterized by comprising: a powder layer forming step, wherein Fe-based metal powder is flattened on a worktable to form a powder layer; an ink impregnation step, wherein an ink containing carbon particles is impregnated in a forming region of the powder layer corresponding to the desired metal sintered body in such a way that the amount of carbon particles supplied is locally different to obtain an ink impregnation layer; an energy line irradiation step, wherein an energy line is irradiated into the forming region, including at least the ink impregnation layer, to obtain a sintered layer; a repetition step, wherein the powder layer forming step, the ink impregnation step, and the energy line irradiation step are repeated once or more to obtain a metal sintered body formed by stacking multiple sintered layers; and a quenching step, wherein the metal sintered body is quenched to obtain a three-dimensional object.

[0010] The three-dimensional model involved in the application example of the present invention is characterized in that it is made of a sintered material of Fe-based metal powder and has a portion in which the carbon concentration decreases from the outer surface toward the interior. Attached Figure Description

[0011] Figure 1 This is a process diagram used to explain the manufacturing method of the three-dimensional model according to the first embodiment.

[0012] Figure 2 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0013] Figure 3 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0014] Figure 4 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0015] Figure 5 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0016] Figure 6 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0017] Figure 7 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0018] Figure 8 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0019] Figure 9 For use in Figure 1 A plan view illustrating the manufacturing method of the three-dimensional object shown.

[0020] Figure 10 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0021] Figure 11 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0022] Figure 12 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0023] Figure 13 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0024] Figure 14 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0025] Figure 15 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0026] Figure 16 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0027] Figure 17 This is a process diagram illustrating the manufacturing method of a three-dimensional model according to the second embodiment.

[0028] Figure 18 For use in Figure 17 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0029] Figure 19 For use in Figure 17 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0030] Figure 20 For use in Figure 17 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0031] Figure 21 For use in Figure 17 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0032] Figure 22 This is a cross-sectional view schematically showing the distribution of carbon concentration in a three-dimensional object according to the third embodiment.

[0033] Figure 23 This is a top view schematically representing the distribution of concentration in the three-dimensional model involved in the variation example. Detailed Implementation

[0034] Hereinafter, the manufacturing method of the three-dimensional model of the present invention and the preferred embodiments of the three-dimensional model will be described in detail based on the accompanying drawings.

[0035] 1. First Implementation Method

[0036] First, the method for manufacturing a three-dimensional model according to the first embodiment will be described.

[0037] Figure 1 This is a process diagram used to explain the manufacturing method of the three-dimensional model according to the first embodiment. Figures 2 to 8 For use in Figure 1 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown. Figure 9 For use in Figure 1 A plan view illustrating the manufacturing method of the three-dimensional object shown. Figures 10 to 16 For use in Figure 1The diagram shows a cross-sectional view illustrating the manufacturing method of the three-dimensional model. Furthermore, in the various figures of this application, the X-axis, Y-axis, and Z-axis are defined as three mutually orthogonal axes. Each axis is indicated by an arrow, with the top side designated as the "positive side" and the base side as the "negative side." In the following description, the positive side of the Z-axis is specifically designated as "up," and the negative side as "down." Additionally, the two directions parallel to the X-axis are referred to as the X-axis directions, the two directions parallel to the Y-axis as the Y-axis directions, and the two directions parallel to the Z-axis as the Z-axis directions.

[0038] The method for manufacturing three-dimensional objects according to the first embodiment is a method known as adhesive spraying, such as... Figure 1 As shown, it has a powder layer forming process S102, an adhesive application process S104, an ink application process S106, a repeating process S108, a sintering process S110, and a quenching process S112.

[0039] In the powder layer forming process S102, Fe-based metal powder 1 is flattened on the molding table 23 (workbench) to form a powder layer 31. In the binder application process S104, binder solution 4 is applied to the forming region 60 in the powder layer 31 corresponding to the desired layered model 6. In the ink application process S106, ink 5 containing carbon particles is applied to the forming region 60 in the powder layer 31. In the repeat process S108, the powder layer forming process S102, the binder application process S104, and the ink application process S106 are repeated at least once. Thus, the forming region 60 to which binder solution 4 and ink 5 are applied can be designated as an ink application layer 51 (unit layer), and multiple ink application layers 51 can be stacked to obtain a layered model 6. In the sintering process S110, the layered model 6 is sintered to obtain a sintered metal body. In the quenching process S112, the sintered metal body is quenched to obtain a three-dimensional model 10. The following is a description of each step in sequence.

[0040] 1.1. Layered Modeling Device

[0041] First, as an example of the apparatus used in the method for manufacturing a three-dimensional model according to the first embodiment, the layered modeling apparatus 2 will be described.

[0042] The layered molding apparatus 2 includes an apparatus body 21 having a powder storage section 211 and a molding section 212, a powder supply elevator 22 disposed in the powder storage section 211, a molding table 23 disposed in the molding section 212, a coating machine 24, a roller 25 and a liquid supply section 26 disposed on the apparatus body 21 in a movable manner.

[0043] The powder storage section 211 is a recessed portion provided in the main body 21 of the device and open at the top. Fe-based metal powder 1 is stored in the powder storage section 211. Furthermore, an appropriate amount of Fe-based metal powder 1 stored in the powder storage section 211 is supplied to the molding section 212 by the coating machine 24.

[0044] A powder supply lift 22 is disposed at the bottom of the powder storage section 211. The powder supply lift 22 is movable in the Z-axis direction while carrying Fe-based metal powder 1. By moving the powder supply lift 22 upward, the Fe-based metal powder 1 placed on the powder supply lift 22 is lifted and overflowed from the powder storage section 211. As a result, the overflowed amount of Fe-based metal powder 1 can be moved towards the molding section 212 by the coating machine 24.

[0045] The molding section 212 is a recessed portion with an opening at the top, located within the main body 21 of the device. A molding table 23 is disposed inside the molding section 212. On the molding table 23, the Fe-based metal powder 1 is leveled and layered by a coating machine 24. Furthermore, the molding table 23 can move in the Z-axis direction while covered with the Fe-based metal powder 1. By appropriately setting the height of the molding table 23, the amount of Fe-based metal powder 1 layered on the molding table 23 can be adjusted.

[0046] The coating machine 24 and the roller 25 can move from the powder storage section 211 to the molding section 212 in the X-axis direction. The coating machine 24 flattens the Fe-based metal powder 1 by dragging it, thereby enabling it to be laid in layers. The roller 25 compresses the flattened Fe-based metal powder 1 from above.

[0047] The liquid supply unit 26 is configured with, for example, an inkjet head or a distributor, and is movable in the molding unit 212 in both the X-axis and Y-axis directions. Furthermore, the liquid supply unit 26 can supply a target amount of adhesive solution 4 and ink 5 to a target location. Additionally, the liquid supply unit 26 may have multiple ejection nozzles in a single head. Moreover, the adhesive solution 4 can be ejected from one ejection nozzle, while the ink 5 can be ejected from another. Furthermore, the head for supplying the adhesive solution 4 and the head for supplying the ink 5 may be separate units.

[0048] 1.2. Powder layer formation process

[0049] In the powder layer forming process S102, Fe-based metal powder 1 is laid on the molding stage 23 to form a powder layer 31. Specifically, as follows... Figure 2 as well as Figure 3As shown, the Fe-based metal powder 1 stored in the powder storage section 211 is dragged onto the molding table 23 using the coating machine 24 and flattened to a uniform thickness. Thus, a product is obtained. Figure 4 The powder layer 31 is shown. At this time, by lowering the upper surface of the molding stage 23 compared to the upper end of the molding section 212, and by adjusting the amount of lowering, the thickness of the powder layer 31 can be adjusted.

[0050] Next, while compressing the powder layer 31 in the thickness direction using the roller, the roller 25 is moved in the X-axis direction. This increases the filling rate of the Fe-based metal powder 1 in the powder layer 31. Furthermore, the compression performed by the roller 25 can be performed only as needed and may be omitted. Alternatively, the powder layer 31 can be compressed using a different means than the roller 25, such as a pressure plate.

[0051] While the constituent materials of Fe-based metal powder 1 are not specifically limited to any metallic material with Fe as the main component, examples of Fe-based metal materials whose hardness can be expected to be increased by adding carbon particles and performing quenching treatment can be included. Fe-based metal materials are not specifically limited, and examples include stainless steel, mechanical structural steel, tool steel, high-speed steel, mold steel, bearing steel, alloy steel, etc.

[0052] Furthermore, any surface treatment, such as silane coupling agent treatment, can be applied to the surface of the Fe-based metal powder 1 as needed.

[0053] Furthermore, while the manufacturing method of Fe-based metal powder 1 is not particularly limited, various atomization methods such as water atomization and gas atomization, as well as pulverization methods, can be listed. Among these, powders manufactured using water atomization often have an oxide film on the particle surface. This oxide film reacts with carbon particles and is reduced during the sintering process described later. Therefore, when using Fe-based metal powder 1 with an accompanying oxide film, the amount of carbon particles contained in the ink 5, or the amount of ink 5 supplied to the forming region 60, can be adjusted by considering the consumption of carbon particles caused by this reduction.

[0054] 1.3. Adhesive application process

[0055] In the adhesive application process S104, such as Figure 5 As shown, a binder solution 4 is supplied to the forming region 60 of the powder layer 31 corresponding to the desired laminated body 6 via the liquid supply unit 26. The binder solution 4 is a liquid containing a binder, solvent, or dispersant. In the forming region 60 where the binder solution 4 is supplied, the particles of the Fe-based metal powder 1 bond together to obtain... Figure 6 The adhesive layer 41 is shown. In the adhesive layer 41, the particles of the Fe-based metal powder 1 are bonded together by an adhesive, thereby having a degree of shape retention that prevents them from breaking due to their own weight.

[0056] Alternatively, the adhesive layer 41 can be heated simultaneously with or after the supply of the adhesive solution 4. This promotes the evaporation of the solvent or dispersant contained in the adhesive solution 4 and promotes the adhesion between particles caused by the curing or hardening of the adhesive. Furthermore, if the adhesive contains a photocurable resin or a UV-curable resin, light irradiation or UV irradiation can be performed instead of heating, or together with heating.

[0057] While the heating temperature is not particularly limited, it is preferably 50°C or higher and 250°C or lower, more preferably 70°C or higher and 200°C or lower. Therefore, when reusing Fe-based metal powder 1 that failed to bond together using the binder solution 4, it is possible to suppress deterioration of the Fe-based metal powder 1 due to heating.

[0058] The adhesive solution 4 is not particularly limited to any liquid containing components capable of binding the Fe-based metal powder 1 particles together. As an example, solvents or dispersants included in the adhesive solution 4 may include water, ethanol, ketones, carboxylates, etc., or a mixture containing at least one of these components. Furthermore, adhesives included in the adhesive solution 4 may include, for example, fatty acids, paraffin wax, microcrystalline wax, polyethylene, polypropylene, polystyrene, acrylic resins, polyamide resins, polyesters, stearic acid, polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene glycol (PEG), etc.

[0059] 1.4. Ink application process

[0060] In the ink application process S106, ink 5 is supplied to the forming region 60 in the powder layer 31. Ink 5 is a liquid containing carbon particles and a dispersant. In this embodiment, ink 5 is supplied to the region corresponding to the forming region 60. Figure 7 The adhesive layer 41 shown is supplied with ink 5. This allows the ink 5 to be impregnated within the adhesive layer 41. As a result, carbon particles are incorporated into the adhesive layer 41, thereby obtaining... Figure 8The ink-applied layer 51 (unit layer) is shown. At this time, the amount of carbon particles supplied to the adhesive layer 41 varies locally. The amount of carbon particles determines the hardness of the quenched structure during the quenching process described later. The quenched structure obtained from martensitic transformation exhibits high hardness and properties such as wear resistance. On the other hand, the quenched structure may lead to a decrease in toughness. Therefore, by setting the quenched structure with hardness locally adjusted only for necessary areas, a three-dimensional object 10 that balances high toughness and high hardness can ultimately be obtained.

[0061] In this embodiment, such as Figure 8 As shown, the amount of carbon particles formed decreases from the outer edge of the ink-applied layer 51 toward the interior (the portion outside the outer edge). Figure 8 for Figure 7 The image shown is a partial enlarged view of the ink applied to layer 51. Figure 8 In this context, the gradient of the amount of carbon particles, or in other words, the gradient of the carbon particle concentration, is represented by the inclination of the arrow marked C1. Figure 8 In the example, arrow C1 is tilted in a manner that the inner side is lower than the outer edge of the ink-applied layer 51. By setting this concentration gradient, a three-dimensional model 10 with high surface hardness and high internal toughness can be obtained. Furthermore, the concentration gradient can be either a smooth gradient (a gradient where the tilt changes continuously) or a stepped gradient (a gradient where the tilt changes discontinuously). As long as there is a gradient on a macroscopic scale, a portion with higher concentration near the surface can exist, taking into account decarburization during sintering. Moreover, in this process, since the amount of carbon particles supplied only needs to vary locally, the pattern is not particularly limited. For example, a region within the forming region 60 where no ink 5 is supplied (a region where the amount of supplied carbon particles is zero) may exist.

[0062] Figure 9 for Figure 8 The diagram shows a plan view of the ink applied to layer 51. Figure 9 In this context, the density of points represents the gradient of carbon particle concentration. Figure 9 In the example, the outer edge of the ink-applying layer 51 is circular, and the concentration of carbon particles increases radially from the center towards the outer edge. Furthermore, the pattern of the concentration gradient is not limited to the pattern illustrated. For example, in a portion of the outer edge, the concentration gradient may be locally steeper or locally gentler compared to other portions. Moreover, the order of the adhesive application step S104 and the ink application step S106 can be reversed. That is, the adhesive solution 4 can be applied after the ink 5 is applied to the forming region 60, and this can be designated as the ink-applying layer 5 (unit layer).

[0063] Carbon particles are particles composed of materials containing carbon monomers as their main component, such as graphite particles, carbon particles, carbon black, carbon fiber, and carbon nanotubes. Furthermore, "main component" refers to a component comprising 50.0% or more by mass. Preferably, the carbon particles are composed of 90.0% or more by mass of carbon monomers.

[0064] Carbon particles are preferably carbon black. Carbon black is an industrially manufactured carbon powder, and its surface properties are homogenized by the presence of various functional groups on the particle surface. Therefore, the ink 5 containing carbon black as carbon powder has excellent stability, allowing the carbon particles to be supplied in a manner that ensures uniform distribution.

[0065] The average particle size of the carbon particles is preferably 1 / 100,000 or more and 1 / 100 or less of the average particle size of the Fe-based metal powder 1, more preferably 1 / 50,000 or more and 1 / 500 or less, and even more preferably 1 / 10,000 or more and 1 / 1000 or less. Therefore, since the carbon particles easily penetrate into the gaps between the particles of the Fe-based metal powder 1, when the ink 5 is supplied to the forming region 60, the carbon particles are easily distributed along the surface of the particles of the Fe-based metal powder 1. As a result, the quenching process described later can be performed more uniformly.

[0066] The average particle size of the carbon particles is preferably 10 nm or more and 10 μm or less, more preferably 10 nm or more and 5 μm or less. Furthermore, the average particle size of the carbon particles refers to the particle size obtained using a laser diffraction particle size distribution measurement device based on a volume reference, when the cumulative mass is 50%. Additionally, in ink 5, carbon particles can be agglomerated to form secondary particles. In this case, the particle size of the secondary particles is set to the particle size of the carbon particles.

[0067] Examples of dispersants include water, organic solvents, and mixtures of water and organic solvents. Examples of water include ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, pure water, and ultrapure water. Examples of organic solvents include water-soluble solvents and non-water-soluble solvents.

[0068] Although the carbon particle content in ink 5 is appropriately set by the ink 5 supply method, it 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, further 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 in ink 5 within the above range, both the processability of ink 5 and the supply efficiency of carbon particles can be balanced. When the carbon particle content in ink 5 is below the lower limit, the supply efficiency will decrease, requiring a large amount of ink 5 to be supplied to the forming region 60, which may reduce the mechanical strength of the ink-applied layer 5. When the carbon particle content in ink 5 is above the upper limit, the viscosity of ink 5 will become too high, which may reduce the processability of ink 5 by the supply method.

[0069] In ink 5, additives other than those mentioned above may also be added. Examples of additives include dispersants, surfactants, wetting agents (anti-drying agents), antioxidants, ultraviolet absorbers, penetration promoters, preservatives, mildew inhibitors, pH adjusters, viscosity adjusters, chelating agents, etc.

[0070] 1.5. Repeated processes

[0071] In the repeating process S108, when the forming region 60, to which the adhesive solution 4 and ink 5 are applied, is designated as the ink application layer 51 (unit layer), the powder layer forming process S102, the adhesive application process S104, and the ink application process S106 are repeated at least once, until the laminate formed by stacking multiple layers of the ink application layer 51 reaches the predetermined shape. In other words, these processes are performed a total of at least twice. Thus, the desired result is obtained. Figure 15 The three-dimensional, layered shape shown is 6.

[0072] Specifically, firstly, in Figure 8 The ink shown is applied to layer 51, as... Figure 10 A new powder layer 31 is formed as shown. Next, as... Figure 11 As shown, adhesive solution 4 is supplied to the forming region 60 in the powder layer 31. Thus, a product is obtained. Figure 12 The adhesive layer 41 shown.

[0073] Next, ink 5 is supplied to the forming region 60 in the powder layer 31. In this embodiment, ink 5 is supplied to... Figure 12 The adhesive layer 41 shown is supplied with ink 5. Thus, ink 5 is obtained. Figure 13 The ink is applied to layer 51 as shown. Figure 14 for Figure 13 The image shown is a partial enlarged view of the ink applied to layer 51. Figure 14In the diagram, the slope of the arrow marking C2 represents the concentration gradient of carbon particles. Figure 14 In the example, the arrow marker C2 is tilted in a way that the inner side is lower than the outer edge of the ink-applied layer 51.

[0074] Although Figure 14 The tilt of the arrow marked C2 shown can also be compared with... Figure 8 The arrows marked C1 shown have the same angle of inclination, but preferably different. This allows the concentration gradient of carbon particles to be optimized according to the shape of the three-dimensional object 10.

[0075] As mentioned above, Figure 15 The stacked structure 6 shown is a stack of multiple ink-applying layers 51 (unit layers). Furthermore, the Fe-based metal powder 1 in the powder layer 31 that does not constitute an ink-applying layer 51 will be recycled and provided for reuse as needed. Additionally, when the repeating process S108 is performed more than twice, the application of ink 5 may be omitted in a portion of the repeating process S108. Furthermore, when the repeating process S108 is performed more than twice, the amount of carbon particles supplied to the forming region 60 may be locally different in a portion of the repeating process S108.

[0076] 1.6. Sintering process

[0077] In sintering process S110, the laminated molded body 6 is subjected to sintering treatment. During the sintering treatment, the laminated molded body 6 is heated to cause a sintering reaction. As a result, a sintered metal body is obtained.

[0078] Although the sintering temperature varies depending on the type or particle size of the Fe-based metal powder 1, as an example, it is preferably 980°C or higher and 1330°C or lower, more preferably 1050°C or higher and 1260°C or lower. Furthermore, the sintering time is preferably 0.2 hours or higher and 7 hours or lower, more preferably 1 hour or higher and 6 hours or lower.

[0079] Examples of atmospheres suitable for sintering include reducing atmospheres such as oxygen, inert atmospheres such as nitrogen and argon, or reduced-pressure atmospheres 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 atmospheric pressure (100 kPa), but it is preferably 10 kPa or less, and more preferably 1 kPa or less.

[0080] 1.7. Quenching process

[0081] In the quenching process S112, the sintered metal body undergoes a quenching treatment. The quenching treatment involves rapidly cooling the sintered metal body after heating it. As a result, in regions where the carbon concentration increases to a predetermined level, the metal microstructure undergoes a martensitic transformation from austenite, thus forming a martensitic-derived quenched microstructure, thereby achieving high hardness. This process that alters the quenched microstructure is called "quenching." On the other hand, in regions where the carbon concentration does not increase, no quenching occurs, and therefore no increase in hardness occurs. Through this quenching treatment, a high hardness is achieved. Figure 16 The three-dimensional model 10 shown.

[0082] The quenching temperature is, for example, above 950℃ and below 1200℃. Furthermore, the quenching time is, for example, above 0.2 hours and below 3 hours. Water cooling, oil cooling, etc., are used for rapid cooling.

[0083] After quenching, tempering can also be performed as needed. Tempering involves reheating the quenched metal sintered body at a lower temperature than the quenching temperature. This allows for a slight reduction in the hardness of the metal sintered body while imparting toughness.

[0084] The tempering temperature is, for example, above 100°C and below 250°C. Furthermore, the tempering time is, for example, above 0.3 hours and below 5 hours.

[0085] 1.8. Effects achieved by the first implementation method

[0086] As described above, the method for manufacturing a three-dimensional model according to the first embodiment includes a powder layer forming step S10, a binder application step S104, an ink application step S106, a repeating step S108, a sintering step S110, and a quenching step S112. In the powder layer forming step S102, Fe-based metal powder 1 is flattened on the molding table 23 (worktable) to form a powder layer 31. In the binder application step S104, a binder solution 4 containing binder is applied to the forming region 60 corresponding to the layered model 6 to be formed in the powder layer 31. In the ink application step S106, ink 5 containing carbon particles is applied to the forming region 60 in such a way that the amount of carbon particles supplied to the forming region 60 is locally different. In the repeating step S108, when the forming region 60, to which the binder solution 4 and 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 more than once to obtain a stacked model body 6 formed by stacking multiple ink application layers 51. In the sintering step S110, the stacked model body 6 is sintered to obtain a sintered metal body. In the quenching step S112, the sintered metal body is quenched to obtain a three-dimensional model 10.

[0087] According to this structure, by locally varying the amount of carbon particles supplied to the forming region 60, the degree of hardening, i.e., the hardness of the hardened structure, in the final three-dimensional model 10 can be locally varied. Thus, for example, the degree of hardening can be increased near the surface of the three-dimensional model 10 to improve hardness, while the degree of hardening can be reduced inside the three-dimensional model 10 to suppress the increase in hardness. As a result, a three-dimensional model 10 with high surface hardness and high internal toughness can be achieved. Since such a three-dimensional model 10 possesses both high toughness and high hardness, for example, wear resistance and durability are simultaneously achieved.

[0088] Furthermore, according to the method described above, the aforementioned effects can be achieved without compromising the advantages of the adhesive spraying method as a layering molding method. Therefore, for example, a region with voids can be formed internally as the forming region 60. This allows for the easy formation of a hollow structure, thereby achieving a lightweight forming region 60 and ultimately obtaining a lightweight three-dimensional model 10 with high surface hardness.

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

[0090] By using the forming region 60 obtained in this way to shape the stacked model body 6 and finally obtain the three-dimensional model 10, it is possible to efficiently manufacture a three-dimensional model 10 with high surface hardness and high internal toughness.

[0091] Furthermore, by setting a gradient in which the concentration of carbon particles changes continuously, it is possible to suppress cracking and other issues arising between the quenched structure layer near the surface and the internal metal structure of the three-dimensional model 10 due to differences in thermal expansion. This improves the reliability of the three-dimensional model 10.

[0092] Alternatively, the amount of carbon particles can be varied between ink-giving layers 51 during repeated step S108, when the ink-giving layers 51 are stacked together (unit layers). For example, in... Figure 14 In the first ink-giving layer 51, the inclination of the arrow marker C1, which represents the gradient of carbon particle concentration, differs from the inclination of the arrow marker C2, which represents the gradient of carbon particle concentration, in the second ink-giving layer 51. This is equivalent to making the amount of carbon particles different between the ink-giving layers 51.

[0093] Based on this structure, the amount of carbon particles supplied can be optimized according to the shape of the three-dimensional object 10. Therefore, the thickness of the layer after high hardness can be optimized according to the shape of the three-dimensional object, and the balance between high hardness and high toughness of the three-dimensional object 10 can be optimized.

[0094] Furthermore, when applying ink 5, it is preferable to adjust the amount of supplied carbon particles in such a way that the carbon concentration in the three-dimensional model 10 is 0.2% by mass or more, and more preferably to adjust the amount of supplied carbon particles in such a way that the carbon concentration in the three-dimensional model 10 is 0.3% by mass or more and 2.2% by mass or less.

[0095] Based on this structure, quenching can be performed more reliably through the quenching process. Furthermore, the carbon concentration immediately after being supplied through ink 5 may sometimes decrease due to subsequent processes. Therefore, it is preferable that the amount of carbon particles supplied through ink 5 is set taking into account this decrease in concentration.

[0096] Furthermore, preferably, the ink application process S106 includes the following operations: Figure 7 as well as Figure 12 As shown, when ink 5 is ejected as droplets from multiple neatly arranged nozzles, the amount of carbon particles varies locally by changing the density of the ejected droplets per unit area.

[0097] When ink 5 is ejected from the multiple nozzles provided in the liquid supply unit 26, the selection and control of the nozzles ejecting ink 5 are easy and accurate. Therefore, based on the above operation, the amount of carbon particles supplied per unit area can be easily and accurately controlled. As a result, it is ultimately possible to easily manufacture a three-dimensional model 10 with a target carbon concentration at a target location.

[0098] Furthermore, in the adhesive application step S104 and the ink application step S106, the application of adhesive solution 4 and ink 5 can be performed almost simultaneously. That is, the adhesive solution 4 and ink 5 can be ejected almost simultaneously from the same or different nozzles. This improves the throughput of the adhesive application step S104 and the ink application step S106. "Almost simultaneously" refers to a time difference of less than 1 second.

[0099] On the other hand, if the case of mixing the sprayed adhesive solution 4 with the ink 5 is taken into consideration, it is preferable to set a time difference between the application of the adhesive solution 4 and the application of the ink 5.

[0100] Alternatively, the adhesive solution 4 and ink 5 can be mixed to form a mixture, which is then sprayed out. In other words, the adhesive application step S104 and the ink application step S106 can be performed simultaneously by applying a liquid containing both the adhesive and carbon particles to the forming region 60. This increases the throughput of both the adhesive application step S104 and the ink application step S106.

[0101] Furthermore, although sintering and quenching can be performed using different processing devices, they can also be performed using a single processing device. That is, it is also possible to perform sintering and quenching continuously without lowering the temperature of the laminated body 6 to room temperature (25°C) by leaving the laminated body 6 in the processing device after the sintering process is completed.

[0102] With this structure, the throughput of these processes can be increased because the sintering process S110 and the quenching process S112 can be carried out continuously.

[0103] Furthermore, the powder layer forming process S102 may also include an operation of compressing the powder layer 31 in the thickness direction. This operation increases the filling rate of the Fe-based metal powder 1 in the powder layer 31. Therefore, even when using Fe-based metal powder 1 with a high bulk density, the density of the three-dimensional object 10 can ultimately be increased.

[0104] 2. Second Implementation Method

[0105] Next, the method for manufacturing a three-dimensional model according to the second embodiment will be described.

[0106] Figure 17 This is a process diagram used to explain the manufacturing method of the three-dimensional model according to the second embodiment. Figures 18 to 21 For use in Figure 17 A cross-sectional view illustrating the manufacturing method of the three-dimensional model shown.

[0107] The second embodiment will now be described, but the description will focus on the differences from the first embodiment, and identical items will be omitted. Furthermore, in the accompanying drawings, the same symbols are used to denote structures identical to those in the first embodiment.

[0108] The manufacturing method for the three-dimensional model involved in the second embodiment is a method called Selective Laser Sintering (SLS), such as... Figure 17 As shown, it has a powder layer forming process S202, an ink impregnation process S204, an energy line irradiation process S206, a repeating process S208, and a quenching process S210.

[0109] 2.1. Layered Modeling Device

[0110] First, the layering modeling apparatus 2A will be described as an example of the apparatus used in the method for manufacturing a three-dimensional model according to the second embodiment.

[0111] Except for the addition of the energy line irradiation unit 27, the layered modeling device 2A is the same as the layered modeling device 2 described above.

[0112] like Figure 19 As shown, the energy line irradiation unit 27 can irradiate the energy line E at any position on the molding table 23. Examples of energy lines E include lasers and electron beams. By irradiating the energy line E, the particles of the Fe-based metal powder 1 can undergo a sintering reaction.

[0113] 2.2 Powder Layer Forming Process

[0114] In the powder layer forming process S202, similar to the powder layer forming process S102 of the first embodiment, the Fe-based metal powder 1 is flattened on the molding table 23 (worktable) to form the powder layer 31.

[0115] 2.3. Ink Impregnation Process

[0116] In the ink impregnation process S204, ink 5 is supplied to the forming region 60 in the powder layer 31 corresponding to the metal sintered body 7 to be formed. This allows the forming region 60 to be impregnated with ink 5. As a result, a [missing information - likely a specific product or process] is obtained. Figure 19 The ink impregnation layer 52 is shown. At this time, the amount of carbon particles supplied to the forming region 60 is locally different. Specifically, compared with... Figure 8 Similarly, the concentration gradient indicated by arrow C1 is set in such a way that the concentration of carbon particles is lower on one side compared to the outer edge of the ink impregnation layer 52. This results in a three-dimensional model 10 with high surface hardness and high internal toughness. Alternatively, a portion of the forming region 60 may contain areas where no ink 5 is supplied (regions where the amount of supplied carbon particles is zero).

[0117] The average particle size of the carbon particles is preferably 1 / 100,000 or more and 1 / 100 or less of the average particle size of the Fe-based metal powder 1, more preferably 1 / 50,000 or more and 1 / 500 or less, and even more preferably 1 / 10,000 or more and 1 / 1000 or less. Therefore, since the carbon particles easily penetrate into the gaps between the particles of the Fe-based metal powder 1, when the ink 5 is supplied to the forming region 60, the carbon particles are easily distributed along the surface of the particles of the Fe-based metal powder 1. As a result, the quenching process described later can be performed more uniformly.

[0118] 2.4. Energy beam irradiation process

[0119] In the energy beam irradiation process S206, such as Figure 19 As shown, energy lines E are irradiated onto the formation region 60, including at least the ink impregnation layer 52, via the energy line irradiation section 27. In the ink impregnation layer 52 irradiated by the energy lines E, the particles of the Fe-based metal powder 1 are sintered together to obtain… Figure 20 The sintered layer 71 is shown. In the sintered layer 71, the particles of Fe-based metal powder 1 are sintered together to form a metal sintered body.

[0120] 2.5. Repeated processes

[0121] In the repeating process S208, the powder layer formation process S202, the ink impregnation process S204, and the energy line irradiation process S206 are repeated at least once until the laminate formed by stacking multiple sintered layers 71 reaches a predetermined shape. Thus, a desired result is obtained. Figure 21 The three-dimensional sintered metal body 7 is shown.

[0122] 2.6. Quenching process

[0123] In the quenching process S210, similar to the quenching process S112 in the first embodiment, the quenched metal body 7 is subjected to quenching treatment. Thus, a product is obtained. Figure 16 The three-dimensional model 10 is shown. Furthermore, in the second embodiment, since the energy supplied through the energy line E is higher, the quenching process is sometimes completed simultaneously with the end of the energy line irradiation step S206. In this case, this step can be omitted, or it can be performed along with a re-quenching process. Alternatively, as in the first embodiment, a tempering process can be performed after the quenching process.

[0124] 2.7. Effects achieved by the second implementation method

[0125] As described above, the method for manufacturing a three-dimensional object according to the second embodiment includes a powder layer forming step S202, an ink impregnation step S204, an energy line irradiation step S206, a repeating step S208, and a quenching step S210. In the powder layer forming step S202, Fe-based metal powder 1 is flattened on a molding table 23 (worktable) to form a powder layer 31. In the ink impregnation step S204, for the forming region 60 in the powder layer 31 corresponding to the metal sintered body 7 to be formed, ink 5 containing carbon particles is impregnated in a manner that locally varies the amount of carbon particles supplied, thereby obtaining an ink impregnation layer 52. In the energy line irradiation step S206, an energy line E is irradiated onto the forming region 60, including at least the ink impregnation layer 52, to obtain a sintered layer 71. In the repeating process S208, the powder layer forming process S202, the ink impregnation process S204, and the energy line irradiation process S206 are repeated more than once to obtain a metal sintered body 7 formed by stacking multiple sintered layers 71. In the quenching process S210, the metal sintered body 7 is quenched to obtain a three-dimensional object 10.

[0126] Based on this structure, by locally varying the amount of carbon particles supplied to the forming region 60, the degree of hardening, i.e., the hardness of the hardened structure, in the final three-dimensional model 10 can be locally varied. Thus, for example, the degree of hardening can be increased near the surface of the three-dimensional model 10 to improve hardness, while the degree of hardening can be reduced inside the three-dimensional model 10 to suppress the increase in hardness. As a result, a three-dimensional model 10 with high surface hardness and high internal toughness can be achieved. Since such a three-dimensional model 10 possesses both high toughness and high hardness, for example, wear resistance and durability are simultaneously achieved.

[0127] Furthermore, according to the method described above, the aforementioned effects can be achieved without compromising the advantages of powder sintering lamination molding as a lamination molding method. Therefore, for example, a region with voids can be set inside the forming region 60. This allows for the lightweighting of the forming region 60, ultimately resulting in a lightweight three-dimensional object 10 with high surface hardness.

[0128] Furthermore, in the method for manufacturing a three-dimensional object according to the second embodiment, ink 5 is applied in such a way that the amount of carbon particles supplied to the outer edge of the forming region 60 is greater than the amount of carbon particles supplied to the portion other than the outer edge of the forming region 60.

[0129] By using the forming region 60 obtained in this way to shape the metal sintered body 7 and finally obtain the three-dimensional object 10, it is possible to efficiently manufacture a three-dimensional object 10 with high surface hardness and high internal toughness.

[0130] Furthermore, by setting a gradient in which the concentration of carbon particles changes continuously, it is possible to suppress cracking and other issues arising between the quenched structure layer near the surface and the internal metal structure of the three-dimensional model 10 due to differences in thermal expansion. This improves the reliability of the three-dimensional model 10.

[0131] 3. Third Implementation Method

[0132] Next, the three-dimensional model involved in the third embodiment will be described.

[0133] Figure 22 This is a cross-sectional view schematically showing the distribution of carbon concentration in the three-dimensional model 10 according to the third embodiment.

[0134] The third embodiment will be described below, but the description will focus on the differences from the first embodiment, and the same items will be omitted.

[0135] exist Figure 22 In the three-dimensional object 10 shown, the density of dots represents the carbon concentration. The three-dimensional object 10 is constructed from a sintered material of Fe-based metal powder 1. Furthermore, the three-dimensional object 10 has a portion 19 where the carbon concentration decreases from the outer surface 11 toward the interior 12. Although in this embodiment the entire three-dimensional object 10 is constructed from portion 19, it is also possible to construct only a portion of the three-dimensional object 10 from portion 19, and to construct the other portions from another structure. Examples of such another structure include structures with a fixed carbon concentration.

[0136] As described above, the three-dimensional objects 10 and 10A involved in this embodiment are made of sintered material of Fe-based metal powder 1 and have a portion 19 where the carbon concentration decreases from the outer surface 11 toward the interior 12.

[0137] This structure allows for a balance between the high hardness of the outer surface 11 and the high toughness of the interior 12.

[0138] Furthermore, preferably, in part 19, the intensity of the gradient that reduces the carbon concentration varies locally, as described above.

[0139] With this structure, when part 19 has, for example, a locally tapered portion and a relatively thickened portion, it is possible to balance high hardness of the outer surface 11 and high toughness of the interior 12 in both portions. In other words, in the tapered portion, if the carbon concentration gradient is gentle, the outer surface 11 becomes too thick, making the volume of the interior 12 relatively small, thus making it difficult to balance high hardness and high toughness. Therefore, by strengthening the carbon concentration gradient in such a portion, it is easier to achieve a balance between high hardness and high toughness.

[0140] The carbon concentration in the outer surface 11 is preferably 0.2% by mass or more, more preferably 0.3% by mass or more and 2.2% by mass or less. If the carbon concentration is within the range described above, the metal structure of the outer surface 11 can be well hardened. As a result, the outer surface 11 can be made to have a high hardness more reliably.

[0141] In addition, the carbon concentration in the outer surface 11 can be measured, for example, by electron probe microanalysis (EPMA).

[0142] Figure 23 This is a top view schematically showing the distribution of carbon concentration in the three-dimensional model 10A involved in the modified example.

[0143] Figure 23 The three-dimensional model 10A shown is a spur gear with multiple external teeth 13 and shaft holes 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 surfaces 15 rub against each other, resulting in wear. Therefore, in the three-dimensional model 10A, the carbon concentration is configured to decrease from the tooth surface 15 towards its interior. Figure 23 In the diagram, the inclination of the arrow marking C3 represents the gradient of carbon concentration in tooth surface 15.

[0144] The carbon concentration decreases from the inner surface 16 of the shaft bore 14 toward the interior. The gradient of carbon concentration on the inner surface 16 of the shaft bore 14 is indicated by the inclination of the arrow marked C4. A crankshaft (not shown) is inserted into the shaft bore 14. Therefore, there is less friction between the surface of the shaft bore 14 and the crankshaft.

[0145] Therefore, it is preferable that the inclination of arrow mark C3 is steeper than that of arrow mark C4. This allows for a higher hardness on the tooth surface 15 compared to the inner surface 16. Conversely, it allows for higher toughness on the inner surface 16 compared to the tooth surface 15. Therefore, according to the modified example of the three-dimensional shape 10A, a gear with superior wear resistance of the tooth surface 15 and durability of the shaft hole 14, and a long service life, can be achieved.

[0146] In manufacturing a three-dimensional object 10A as described above, the following method can also be used, namely, to reduce the amount of carbon particles from... Figure 8 The ink 5 is applied in a manner where the intensity of the gradient, which decreases locally as it moves inward from the outer edge of the forming region 60 shown, is locally different. That is, the inclination of the arrow marker C3, representing the gradient of carbon concentration in the tooth surface 15, can also be different from the inclination of the arrow marker C4, representing the gradient of carbon concentration in the inner surface 16. For example... Figure 23 As shown, arrow C3 indicates the gradient of carbon concentration on the cross section connecting points D1 and D2, which traverses the tooth surface 15. Arrow C4 indicates the gradient of carbon concentration on the cross section connecting points D3 and D4, which traverses the inner surface 16.

[0147] Based on this structure, when the manufactured three-dimensional model 10A is applied to a gear, high hardness of the tooth surface 15 can be achieved, while high toughness of the inner surface 16 of the shaft hole 14 can be achieved simultaneously. As a result, a gear with a long service life can be easily produced.

[0148] The three-dimensional shapes 10 and 10A described above can be used as components for various types of vehicles, such as automobiles, bicycles, railcars, ships, aircraft, space transport machines, personal computers, portable telephone terminals, tablet computers, wearable devices, electrical equipment like refrigerators, washing machines, air conditioning and heating equipment, machinery like machine tools and semiconductor manufacturing equipment, complete sets of equipment like nuclear power plants, thermal power plants, hydroelectric power plants, oil refineries, and petrochemical complexes, as well as watch parts, metal tableware, jewelry, and eyeglass frames, either as a whole or as part of a decorative item.

[0149] The manufacturing method and the three-dimensional model of the present invention have been described above based on the illustrated embodiments, but the present invention is not limited thereto. For example, the three-dimensional model of the present invention may also be a three-dimensional model with any additional components added in the embodiments described above.

[0150] Furthermore, the method for manufacturing three-dimensional objects according to the present invention can also be a method for manufacturing three-dimensional objects by adding processes for any purpose in the described embodiment.

[0151] Symbol Explanation

[0152] 1…Fe-based metal powder; 2…Laminated molding device; 2A…Laminated molding device; 4…Binder solution; 5…Ink; 6…Laminated molded body; 7…Sintered metal body; 10…Three-dimensional molded object; 10A…Three-dimensional molded object; 11…Outer surface; 12…Inner surface; 13…Outer teeth; 14…Shaft hole; 15…Tooth surface; 16…Inner surface; 19…Part; 21…Main body of the device; 22…Powder supply elevator; 23…Molding table; 24…Coating machine; 25…Roller; 26…Liquid supply section; 27…Energy beam irradiation section; 31…Powder layer; 41…Binder layer; 51…Ink application layer; 52…Ink impregnation layer; 60… Forming area; 71…Sintered layer; 211…Powder storage section; 212…Shaping section; C1…Arrow mark; C2…Arrow mark; C3…Arrow mark; C4…Arrow mark; D1…Point; D2…Point; D3…Point; D4…Point; E…Energy line; S102…Powder layer forming process; S104…Binder application process; S106…Ink application process; S108…Repeated process; S110…Sintering process; S112…Quenching process; S202…Powder layer forming process; S204…Ink impregnation process; S206…Energy line irradiation process; S208…Repeated process; S210…Quenching process.

Claims

1. A method of manufacturing a three-dimensional shaped object, characterized by, have: In the powder layer formation process, the Fe-based metal powder is flattened on the worktable to form a powder layer. In the adhesive application process, an adhesive solution containing adhesive is applied to the forming region in the powder layer corresponding to the layered shape to be formed; The ink application process involves applying ink containing the carbon particles to the forming region in a manner that locally varies the amount of carbon particles supplied to the forming region. By repeating the process of setting the forming area to which the adhesive solution and the ink are applied as a unit layer, the powder layer forming process, the adhesive application process, and the ink application process are performed more than once to obtain the stacked shape formed by stacking multiple unit layers. The sintering process involves sintering the layered molded body to obtain a sintered metal body. The quenching process involves quenching the sintered metal body and transforming the metal microstructure of the carbon-treated regions of the sintered metal body into martensite to obtain a three-dimensional object.

2. The method for manufacturing a three-dimensional object as described in claim 1, wherein, The ink is supplied in such a manner that the amount of carbon particles supplied to the outer edge of the forming region is greater than the amount of carbon particles supplied to the portion of the forming region other than the outer edge.

3. The method for manufacturing a three-dimensional object as described in claim 2, wherein, The ink is applied in such a way that the intensity of the gradient of the amount of carbon particles decreases locally from the outer edge toward the interior.

4. The method for manufacturing a three-dimensional model as described in any one of claims 1 to 3, wherein, In the repeated process, when the unit layers are stacked on top of each other, the amount of carbon particles is made to vary between the forming regions.

5. The method for manufacturing a three-dimensional object as described in claim 1, wherein, The amount of carbon particles supplied by the ink is adjusted such that the carbon concentration in the three-dimensional model is 0.2% by mass or more.

6. The method for manufacturing a three-dimensional object as described in claim 1, wherein, The average particle size of the carbon particles is greater than 1 / 100,000 and less than 1 / 100 of the average particle size of the Fe-based metal powder.

7. The method for manufacturing a three-dimensional object as described in claim 1, wherein, The ink application process includes the following operation: when the ink is ejected as droplets from a plurality of neatly arranged nozzles, the amount of carbon particles is locally varied by changing the density of the droplets ejected per unit area.

8. The method for manufacturing a three-dimensional object as described in claim 1, wherein, The adhesive application process and the ink application process are performed simultaneously by applying a liquid containing both the adhesive and the carbon particles to the forming area.

9. The method for manufacturing a three-dimensional object as described in claim 1, wherein, The sintering process and the quenching process are carried out continuously by performing the sintering process and the quenching process continuously without lowering the temperature of the laminated body to room temperature.

10. The method for manufacturing a three-dimensional object as described in claim 1, wherein, This includes the operation of compressing the powder layer in the thickness direction.

11. A method of manufacturing a three-dimensional shaped object, characterized by, have: In the powder layer formation process, the Fe-based metal powder is flattened on the worktable to form a powder layer. In the ink impregnation process, an ink impregnation layer is obtained by impregnating the carbon particles with ink in a manner that locally varies the amount of carbon particles supplied to the forming region in the powder layer corresponding to the metal sintered body to be formed. An energy line irradiation process involves irradiating the formation region, including at least the ink impregnation layer, with energy lines to obtain a sintered layer. The powder layer formation process, the ink impregnation process, and the energy line irradiation process are repeated more than once to obtain the metal sintered body formed by stacking multiple sintered layers; The quenching process involves quenching the sintered metal body and transforming the metal microstructure of the carbon-treated regions of the sintered metal body into martensite to obtain a three-dimensional object.

12. The method for manufacturing a three-dimensional object as described in claim 11, wherein, The ink is supplied in such a manner that the amount of carbon particles supplied to the outer edge of the forming region is greater than the amount of carbon particles supplied to the portion of the forming region other than the outer edge.

13. The method for manufacturing a three-dimensional object as described in claim 11 or 12, wherein, The average particle size of the carbon particles is greater than 1 / 100,000 and less than 1 / 100 of the average particle size of the Fe-based metal powder.

14. The method for manufacturing a three-dimensional object as described in claim 11, wherein, This includes the operation of compressing the powder layer in the thickness direction.

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