Method for manufacturing three-dimensional object, three-dimensional object, titanium-containing intermediate three-dimensional object, titanium-containing three-dimensional object

Abstract

To provide a producing method capable of molding a three-dimensional molded article using metal powder containing titanium.SOLUTION: A method for producing a three-dimensional molded article includes: a molding step of applying a binding fluid to a metal powder containing titanium to mold an intermediate molded article; and a sintering step of sintering the intermediate molded article to produce a three-dimensional molded article, and the molding step is performed under vacuum or in an inert gas atmosphere. The molding process is performed in the molding area, but if after the molding process and before the sintering process, a curing process is further provided to cure the bonding fluid in the intermediate molded article in a curing area different from the molding area, the curing process is performed under vacuum or in an inert gas atmosphere. A transfer path for transferring the intermediate molded article that has been subjected to the molding step from the molding area to the curing area is under vacuum or in an inert gas atmosphere.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, the binder jet method has been attracting attention as a method for forming three-dimensional objects. In the binder jet method, for example, powder is supplied to the entire planar area, and then the powder is leveled using a recoater to form a powder layer. Then, based on two-dimensional image data (slice data) of the desired three-dimensional object, a liquid (binder) is applied to a partial area of ​​the powder layer corresponding to the slice data to solidify the powder. Then, by repeating the above-described formation of a powder layer and partial solidification by applying a liquid, a three-dimensional object is formed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-196968 Summary of the Invention [Problem to be solved by the invention]

[0004] Currently, the production of three-dimensional objects by the binder jet method using titanium-containing metal powder is rarely practiced.

[0005] In view of the above circumstances, the present invention provides a manufacturing method that enables a three-dimensional object to be formed using a metal powder containing titanium, the three-dimensional object formed by the method, a titanium-containing intermediate three-dimensional object, and a titanium-containing three-dimensional object. [Means for solving the problem]

[0006] The present invention has been made to solve the above-mentioned problems, and the method for manufacturing a three-dimensional object of the present invention comprises a manufacturing step of applying a binding fluid to a metal powder containing titanium (hereinafter referred to as titanium-containing metal powder) to manufacture an intermediate object, and a sintering step of sintering the intermediate object to produce a three-dimensional object, wherein the manufacturing step is carried out in a vacuum or in an inert gas atmosphere.

[0007] In the method for manufacturing a three-dimensional object of the present invention, the modeling step is performed in a modeling area, and a hardening step is provided in which the bonding fluid contained in the intermediate object is hardened in a hardening area different from the modeling area after the modeling step and before the sintering step, and the hardening step is performed under vacuum or in an inert gas atmosphere.

[0008] In the method for manufacturing a three-dimensional object according to the present invention, the intermediate object that has undergone the modeling step may be moved from the modeling region to the curing region along a path that is under vacuum or an inert gas atmosphere.

[0009] The method for producing a three-dimensional object of the present invention further includes a metal powder removal step of removing the titanium-containing metal powder adhering to the periphery of the intermediate object after the hardening step and before the sintering step, and the metal powder removal step is carried out under vacuum or in an inert gas atmosphere.

[0010] In the method for manufacturing a three-dimensional object of the present invention, the metal powder removal step is performed in a powder removal area different from the hardening area, and a moving path along which the intermediate object that has undergone the hardening step is moved from the hardening area to the powder removal area is under vacuum or an inert gas atmosphere.

[0011] In the method for manufacturing a three-dimensional object of the present invention, the oxygen concentration in the atmosphere is measured in the modeling step.

[0012] In the method for producing a three-dimensional object of the present invention, the average particle diameter D of the titanium-containing metal powder 50is characterized by being 45 μm or less.

[0013] In the method for producing a three-dimensional object of the present invention, the average particle diameter D of the titanium-containing metal powder 50 is characterized by being 40 μm or less.

[0014] In the method for producing a three-dimensional object of the present invention, the average particle diameter D of the titanium-containing metal powder 50 is characterized by being 25 μm or more.

[0015] In the method for producing a three-dimensional object of the present invention, the average particle diameter D of the titanium-containing metal powder 50 is characterized by being 40 μm or more.

[0016] In the method for manufacturing a three-dimensional object of the present invention, the density of the intermediate object after the hardening step and before the sintering step is 2.0 g / cm 3 The present invention is characterized in that:

[0017] In the method for manufacturing a three-dimensional object of the present invention, the density of the intermediate object after the hardening step and before the sintering step is 2.2 g / cm 3 The present invention is characterized in that:

[0018] In the method for manufacturing a three-dimensional object of the present invention, the density of the intermediate object after the hardening step and before the sintering step is 2.5 g / cm 3 The present invention is characterized in that:

[0019] In the method for producing a three-dimensional object according to the present invention, the density of the three-dimensional object after the sintering step is 3.5 g / cm 3 The present invention is characterized in that:

[0020] In the method for producing a three-dimensional object of the present invention, the density of the three-dimensional object after the sintering step is 3.75 g / cm 3 The present invention is characterized in that:

[0021] In the method for producing a three-dimensional object according to the present invention, the density of the three-dimensional object after the sintering step is 4.0 g / cm 3 The present invention is characterized in that:

[0022] In the method for producing a three-dimensional object of the present invention, the average particle diameter D of the titanium-containing metal powder 50 is 40 μm or less, and the density of the intermediate shaped object after the hardening step and before the sintering step is 2.5 g / cm 3 The density of the three-dimensional object after the sintering step is 4.0 g / cm 3 The present invention is characterized in that:

[0023] In the method for producing a three-dimensional object of the present invention, the average particle diameter D of the titanium-containing metal powder 50 is 40 μm or more, and the density of the intermediate shaped object after the hardening step and before the sintering step is 2.5 g / cm 3 The density of the three-dimensional object after the sintering step is 4.0 g / cm 3 The present invention is characterized in that:

[0024] In the method for producing a three-dimensional object of the present invention, the three-dimensional object after the sintering step contains 0.06 wt % or less of carbon based on the weight of the three-dimensional object.

[0025] In the method for manufacturing a three-dimensional object of the present invention, the manufacturing process includes a metal powder layer forming process in which the titanium-containing metal powder is supplied to a region that will become planar to form a metal powder layer, and a bonding fluid applying process in which the three-dimensional object is divided into a plurality of layers (hereinafter referred to as three-dimensional printing-side layers) along a predetermined direction and the bonding fluid is applied to a partial region of the metal powder layer based on the planar shape of the three-dimensional printing-side layer to bond the titanium-containing metal powder in the partial region to form a layer in the intermediate object (hereinafter referred to as intermediate printing-side layer), wherein the metal powder layer forming process and the bonding fluid applying process are repeated in order, so that the intermediate printing-side layers are sequentially stacked to form the intermediate object.

[0026] In the method for manufacturing a three-dimensional object of the present invention, the inert gas contains at least one of nitrogen and a rare gas.

[0027] The three-dimensional object of the present invention is characterized by being produced by the above-described production method.

[0028] Furthermore, the three-dimensional object of the present invention is a three-dimensional object manufactured by the method for manufacturing a three-dimensional object described above, characterized in that a surface layer near region including the top three-dimensional modeling side layer of the three-dimensional object stacked in the modeling process has a higher porosity than an inner core region.

[0029] Furthermore, the three-dimensional object of the present invention is a three-dimensional object manufactured by the method for manufacturing a three-dimensional object described above, characterized in that the three-dimensional object has an inclined surface on its surface that is inclined with respect to the stacking direction of the plurality of three-dimensional modeling side layers, the inclined surface has steps between adjacent three-dimensional modeling side layers that are formed in a continuous staircase shape along the inclination direction, and the steps are stacking marks that represent the boundaries between adjacent three-dimensional modeling side layers.

[0030] The titanium-containing intermediate three-dimensional shaped object of the present invention is a titanium-containing intermediate three-dimensional shaped object that is obtained by applying a binding fluid to a metal powder containing titanium (hereinafter referred to as titanium-containing metal powder), which is three-dimensionally shaped and hardened, and is in a state before being sintered, and has a density of 2.0 g / cm. 3 The present invention is characterized in that:

[0031] The titanium-containing three-dimensionally shaped object of the present invention is a titanium-containing three-dimensionally shaped object obtained by applying a binding fluid to a metal powder containing titanium (hereinafter referred to as titanium-containing metal powder), three-dimensionally shaping the object, hardening the object, and sintering the object, and has a density of 3.5 g / cm. 3 The present invention is characterized in that:

[0032] The titanium-containing three-dimensionally shaped object of the present invention is a titanium-containing three-dimensionally shaped object obtained by adding a binding fluid to a metal powder containing titanium (hereinafter referred to as titanium-containing metal powder), three-dimensionally shaping the object, hardening the resulting object, and sintering the resulting object, and is characterized by containing 0.06 wt % or less of carbon based on the weight of the three-dimensionally shaped object.

[0033] The titanium-containing three-dimensionally shaped object of the present invention is a titanium-containing three-dimensionally shaped object obtained by applying a binding fluid to a metal powder containing titanium (hereinafter referred to as titanium-containing metal powder), three-dimensionally shaping the object, hardening the object, and then sintering the object, and is characterized in that the surface-near-surface region of the three-dimensionally shaped object has a higher porosity than the inner core region. [Effects of the Invention]

[0034] The method for manufacturing a three-dimensional object of the present invention has the excellent effect of being able to manufacture a three-dimensional object using a metal powder containing titanium. [Brief explanation of the drawings]

[0035] [Figure 1] 1 is a flowchart of a method for manufacturing a three-dimensional object according to the present invention. [Figure 2] 1A is a photograph of an intermediate object manufactured by the method for manufacturing a three-dimensional object of the present invention, and FIG. 1B is a photograph of a three-dimensional object manufactured by the method for manufacturing a three-dimensional object of the present invention. [Figure 3] 1A to 1D are schematic diagrams arranged in chronological order to explain an example of the method for producing a three-dimensional object of the present invention. [Figure 4] 1A to 1D are schematic diagrams arranged in chronological order to explain an example of the method for producing a three-dimensional object of the present invention. [Figure 5] 1A is a schematic plan view showing the layout of an apparatus for carrying out the method for producing a three-dimensional object of the present invention, and FIG. 1B is a schematic plan view showing a curing apparatus used in the curing step of the present invention. [Figure 6]6A is a perspective view of a three-dimensional object manufactured by the method for manufacturing a three-dimensional object of the present invention, and FIG. 6B is an enlarged schematic view of a dotted line region F in the cross section viewed from the arrow EE in FIG. [Figure 7] 7A is a perspective view of a three-dimensional object manufactured by the method for manufacturing a three-dimensional object of the present invention, and FIG. 7B is an enlarged schematic view of a dotted line region N in a cross section taken along arrow JJ in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0036] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Figures 1 to 7 show an example of an embodiment of the present invention, and in the figures, parts with the same reference numerals as in Figure 3 represent the same items.

[0037] <Configuration of the manufacturing method for a three-dimensional object> In the method for manufacturing a three-dimensional object according to the present embodiment, first, an intermediate object 100 (see FIG. 2(A)) is prepared using a metal powder containing titanium (hereinafter referred to as a titanium-containing metal powder), and then a final three-dimensional object 200 (see FIG. 2(B)) is prepared from the intermediate object 100. In this specification, the intermediate object 100 is an unfinished three-dimensional object containing titanium, and in this sense, may be referred to as a titanium-containing intermediate three-dimensional object 100 as appropriate. Furthermore, the three-dimensional object 200 may be referred to as a titanium-containing three-dimensional object 200 as appropriate, since it is a three-dimensional object containing titanium. The method for manufacturing a three-dimensional object according to the present embodiment will be described in detail below. As shown in FIG. 1, the method for manufacturing a three-dimensional object according to the present embodiment includes a manufacturing step (S100), a hardening step (S110), a metal powder removing step (S120), and a sintering step (S130).

[0038] <Modeling process> In the manufacturing process, an intermediate manufactured object 100 is manufactured in a manufacturing region using a titanium-containing metal powder. The titanium-containing metal powder may be a powder composed solely of pure titanium particles (pure titanium particles). Alternatively, it may be a powder composed of metal particles containing a metal other than titanium but mainly composed of titanium (main titanium-containing metal particles). Furthermore, it may be a metal powder composed of metal particles containing titanium but mainly composed of a metal other than titanium (secondary titanium-containing metal particles). The titanium-containing metal powder may also contain metal particles that do not contain titanium (non-titanium metal particles) in addition to the pure titanium particles, main titanium-containing metal particles, and secondary titanium-containing metal particles. Furthermore, it may contain particles other than metals (non-metal particles). When non-titanium metal particles are mixed, the non-titanium metal may be the main component of the powder as a whole. When non-metal particles are mixed, the non-metal component may be the main component of the powder as a whole.

[0039] Furthermore, the average particle size D of the titanium-containing metal powder 50 The average particle diameter D of the titanium-containing metal powder is preferably 60 μm or less, more preferably 45 μm or less, and even more preferably 40 μm or less. 50 From the above, the average particle size D of the titanium-containing metal powder is preferably 20 μm or more, more preferably 25 μm or more, and even more preferably 40 μm or more. 50 In this specification, the average particle size D is preferably in the range of 20 to 60 μm, more preferably in the range of 20 to 45 μm, and even more preferably in the range of 20 to 40 μm. 50 The average particle size D is the particle size at which the cumulative volume reaches 50% on the cumulative curve that represents the particle size distribution on a volume basis, with the total volume of the powder mass being measured taken as 100%, and is also called the median diameter. 50 Specifically, the average particle size D is measured using a measuring device that uses the laser diffraction and scattering method. 50 When titanium-containing metal powder having a small average particle diameter D is used for molding, the intermediate molded object 100 or the three-dimensional molded object described later can be produced with high density. 50However, as described below, since the manufacturing process is carried out under vacuum or in an inert gas atmosphere, the risk of dust explosions can be reduced at the same time. From the viewpoint of improving manufacturing efficiency, the average particle diameter D of the titanium-containing metal powder is 50 It is also preferable that the average particle size D is 40 μm or more, more preferably 50 μm or more, and further preferably 60 μm or more. 50 Since the thickness is large, it is possible to quickly penetrate the bonding fluid described below.

[0040] The intermediate object 100 shown in Fig. 2(A) is a three-dimensional object produced in the modeling process. On the other hand, the three-dimensional object 200 shown in Fig. 2(B) is a three-dimensional object obtained by sintering the intermediate object 100. As shown in Figs. 2(A) and 2(B), in this embodiment, the three-dimensional object 200 is a reduced version of the intermediate object 100.

[0041] Titanium-containing metal powder may ignite due to static electricity in the surrounding area, for example. If titanium-containing metal powder is scattered in the atmosphere during the manufacturing process and is present in an oxygen atmosphere, combustion of the ignited titanium-containing metal powder in the atmosphere may be accelerated, potentially leading to a dust explosion. On the other hand, if the atmosphere during the manufacturing process is filled with nitrogen gas, an inert gas, even if titanium-containing metal powder is scattered or suspended in the atmosphere, combustion is suppressed, and no dust explosion occurs. Therefore, in this embodiment, the manufacturing process is preferably performed in a nitrogen gas atmosphere. Specifically, the manufacturing area to which the titanium-containing metal powder is supplied is preferably surrounded by a cover to create a nitrogen gas atmosphere.

[0042] The inert gas filling the atmosphere in the modeling step may be a gas other than nitrogen. Examples of inert gases other than nitrogen include rare gases such as argon. The "atmosphere filled with an inert gas" means, for example, an atmosphere in which the oxygen concentration is preferably 1.0% or less, more preferably 0.5% or less, and even more preferably 0.1% or less. The oxygen concentration in the atmosphere is preferably measured continuously or at regular intervals by an oxygen concentration measuring unit (not shown) while the intermediate object 100 is being modeled in the modeling step (S100). The measurement of the oxygen concentration in the modeling step (S100) is preferably also performed in the curing step (S110) and the metal powder removal step (S120).

[0043] Next, the details of the manufacturing process will be described. Here, an example will be described in which the manufacturing process is performed using a binder jet method, but the present invention is not limited to this, and the manufacturing process may be performed using other manufacturing methods for three-dimensional objects. As shown in FIG. 1, the manufacturing process in this embodiment includes a metal powder layer forming step (S101), a bonding fluid applying step (S102), and a temporary curing step (S103). In this embodiment, the manufacturing process is performed using a manufacturing apparatus 1 shown in FIG. 3(A).

[0044] As shown in FIG. 3(A), the modeling apparatus 1 includes a modeling tank 10 having a recess 11 with its opening 111 facing upward, a storage unit 12 that stores metal powder and supplies the metal powder downward, a roller 13, a bonding fluid discharge unit 14 having a nozzle 140 that discharges a bonding fluid, a heating unit 15, a vibration unit 16, a relative movement unit (not shown), and an elevator unit (not shown). A stage 17 that forms the bottom of the recess 11 in the modeling tank 10 is raised and lowered in the depth direction of the recess 11 by the elevator. As a result, the height and depth of the stage 17 can be maintained while the depth of the recess 11 is changed, thereby expanding or reducing the space above the stage 17 within the recess 11 in the vertical direction. The space within the recess 11 forms a modeling region V in which an intermediate model 100 is provided. The modeling apparatus 1 includes a modeling region V, and further includes a modeling space K that surrounds the upper storage unit 12, the roller 13, and the combined fluid discharge unit .

[0045] In this embodiment, in order to eliminate the risk of dust explosion of the titanium-containing metal powder in the modeling apparatus 1, at least the modeling region V is filled with inert gas. Preferably, the modeling space K is filled with inert gas. It is preferable to provide a cover that covers the modeling region V or the modeling space K, thereby placing the modeling region V or the modeling space K under an inert gas atmosphere. This cover separates the modeling region V or the modeling space K from the external space.

[0046] The storage section 12 has a mesh section 120 on its lower side. In this embodiment, the mesh size of the mesh section 120 is preferably within a range of 100 to 200 μm, and more preferably within a range of 130 to 160 μm. The vibration section 16 applies vibrations to the mesh section 120 or the storage section 12. This allows the metal powder stored in the storage section 12 to pass through the mesh section 120 and fall to the lower side. The vibration section 16 is assumed to be configured, for example, by an ultrasonic oscillator that applies ultrasonic vibrations to the mesh section 120, but is not limited thereto and may be configured by other means. The storage section 12 may also be configured to have an opening (not shown) for supplying the metal powder to the outside and an on-off valve (not shown) for opening and closing the opening. The mesh section 120 may also be provided with an on-off valve (not shown).

[0047] The relative movement unit moves the storage unit 12, roller 13, combined fluid discharge unit 14, and heating unit 15 horizontally relative to the modeling tank 10. As shown in FIG. 3(A), in this embodiment, the storage unit 12, roller 13, and vibration unit 16 are connected to each other. In this specification, this assembly is referred to as a recoater, as appropriate. The heating unit 15 is also connected to the recoater. Therefore, the recoater (storage unit 12, roller 13, and vibration unit 16) and heating unit 15 are moved integrally by the relative movement unit. Here, the relative movement is illustrated in a single axial direction, i.e., the horizontal direction in FIGS. 3 and 4, i.e., the movement directions A and B, or a direction perpendicular to the movement directions A and B. However, the relative movement may also be performed in two axial directions constituting a plane. In FIGS. 3(B) to 3(D) and 4(A) to 3(D), only necessary parts of the modeling apparatus 1 are depicted, and the rest are omitted. It should be noted that the scope of the present invention also includes a configuration in which the recoater and the heating unit 15, or the storage unit 12, the roller 13, and the heating unit 15, move independently relative to each other.

[0048] <Metal powder layer formation process> In the metal powder layer forming step S101, titanium-containing metal powder is supplied to the building region V in the recess 11 of the building tank 10 of the building apparatus 1 to form a second metal powder layer 23 with a flat surface. In FIG. 3(A), a first layer 101 of the intermediate product 100 has already been formed in the first metal powder layer 21 in the recess 11 of the building tank 10 by the immediately preceding building step. Note that each layer of the intermediate product 100, including the first layer 101, may be referred to as an intermediate building-side layer. The stage 17 has been lowered so that the top surface of the first layer 101 is below the opening 111 of the recess 11 in the depth direction D of the recess 11. As a result, a storage region 112 capable of storing new titanium-containing metal powder is formed in the building region V of the recess 11 between the top surface of the first layer 101 and the opening 111 of the recess 11. The accommodation area 112 is a unit area of ​​one layer when the fabrication area V (recess 11) is divided into layers along the depth direction D of the fabrication area V. The thickness of the accommodation area 112 is, for example, in the range of approximately 30 to 200 μm. Therefore, the accommodation area 112 can be regarded as a flat area. The fabrication tank 10 and the stage 17 are portable and can also serve as a transport container for downstream processes.

[0049] Next, as shown in FIG. 3(B), the relative moving unit moves the recoater from one end of the recess 11 to the other end in the moving direction A while positioning the recoater above (directly above) the recess 11. At this time, the roller 13 is positioned behind the mesh unit 120 in the advancing direction (moving direction A) of the recoater and at a position where the lower end of the circumferential surface of the roller 13 is flush with the upper end (opening 111) of the recess 11 in the depth direction D of the printing region V (recess 11). The moving direction A is a direction perpendicular to the depth direction D of the recess 11, and refers to, for example, a direction parallel to a predetermined side of the recess 11 when the recess 11 is viewed from above (the left-right direction in FIG. 3(B)). Then, while the accommodation unit 12 is positioned above (directly above) the recess 11 and moving from one end of the recess 11 to the other end, the vibration unit 16 applies vibration to the mesh unit 120. As a result, as shown in Figure 3(B), the titanium-containing metal powder 20 passes through the mesh portion 120 and falls into the storage area 112 in a line (curtain shape) extending in the front-to-back direction in Figure 3(B) (the depth direction of the paper in Figure 3(B)), and the titanium-containing metal powder 20 accumulates in the storage area 112. At this time, the titanium-containing metal powder 20 accumulates to the extent that it exceeds the opening 111 and rises above the recess 11 (storage area 112). The area where the titanium-containing metal powder 20 is filled up to the opening 111 is referred to as the filled powder area 22A, and the area where the titanium-containing metal powder 20 exceeds the opening 111 and rises above the recess 11 (filled powder area) is referred to as the surplus powder area 22B.

[0050] When the mesh portion 120 passes the other end of the recess 11, the vibration by the vibrating portion 16 is stopped, and the titanium-containing metal powder 20 stops falling from the mesh portion 120. This completes the supply process of the titanium-containing metal powder 20 from the storage portion 12 to the storage area 112. After the supply process is completed, as shown in FIG. 3(C), the roller 13 is rotated clockwise by a roller drive unit (not shown) to level the excess powder area 22B, and moves together with the storage portion 12 along the movement direction A. As shown in FIG. 3(C), the excess powder area 22B that the roller 13 has passed through is leveled by the roller 13 and disappears, leaving only the filled powder area 22A. As shown in FIG. 3(D), the above leveling process is performed until the roller 13 reaches the other end of the recess 11, so that only the filled powder area 22A remains, and a second metal powder layer 23 is formed in the storage area 112. Note that when the roller 13 passes the other end of the recess 11, the rotation of the roller 13 stops. Thereafter, the recoater further advances in the movement direction A and waits on the left side of the modeling tank 10. Incidentally, in this embodiment, the leveling process is started after the supply process is completed, but this is not limited thereto, and the recoater and the control of the recoater may be configured so that the leveling process is started while the supply process is in progress and before it is completed.

[0051] <Coupling fluid application step> In the binding fluid application step S102, a binding fluid (binder) 24 that binds the titanium-containing metal powder 20 is applied (coated or filled) to a partial region (application region) of the second metal powder layer 23 formed in the metal powder layer formation step S101. The binding fluid 24 is applied to a corresponding region of the second metal powder layer 23 based on the planar shape of a desired layer when the desired three-dimensional object 200 is divided into multiple layers along a predetermined direction. Note that each of the multiple layers constituting the three-dimensional object 200 may be referred to as a three-dimensional printing-side layer to distinguish it from the intermediate printing-side layer of the intermediate object 100. More specifically, the application region of the binding fluid 24 is determined by two-dimensional image data (slice data) obtained by dividing three-dimensional data of a three-dimensional object (here, identical to the intermediate object 100) that has been enlarged in advance by the amount of reduction due to the sintering step described below into multiple layers in a predetermined direction (here, the depth direction D).

[0052] As shown in FIG. 4A , in this embodiment, the combined fluid discharge unit 14 discharges the combined fluid 24 from above downward onto the second metal powder layer 23 through the nozzle 140. The combined fluid discharge unit 14 is moved by the relative movement unit from its initial position to above (directly above) the second metal powder layer 23, and moves back and forth relative to the second metal powder layer 23 between one end and the other end of the recess 11 in an orthogonal direction C (the depth direction of the paper in FIG. 4A ) that is parallel to the surface of the second metal powder layer 23 and perpendicular to the movement direction A. During this movement, the combined fluid discharge unit 14 discharges the combined fluid 24 through the nozzle 140 onto the application area. The combined fluid discharge unit 14 may move back and forth relative to the second metal powder layer 23 once or multiple times. The direction of the relative reciprocation may be parallel to the movement direction A. When the combined fluid discharge unit 14 finishes discharging the combined fluid 24, the combined fluid discharge unit 14 returns to its initial position by the relative movement unit. The region to which the bonding fluid 24 is applied becomes the second layer 102 of the intermediate object 100. Thereafter, as shown in FIG. 4(B), the elevator unit lowers the stage 17 downward in the depth direction D of the recess 11, thereby providing a new accommodation region 112 in the recess 11.

[0053] <Temporary curing process> In the pre-curing step S103, the binding fluid 24 applied to the second metal powder layer 23 is pre-cured in situ. Pre-curing the applied binding fluid 24 bonds the titanium-containing metal powder 20 contained in the second layer 102. In this embodiment, the binding fluid 24 is a thermosetting binder whose curing is accelerated by heating. The heating temperature depends on the thermosetting characteristics of the binding fluid 24 (binder), and 50°C is an example. Taking advantage of this, in this embodiment, the second layer 102 is heated by the heating unit 15 to pre-cur the binding fluid 24 (binder). As described above, the heating unit 15 is in a standby state on the left side of the modeling tank 10, along with the recoater. 4(B) and 4(C), in the provisional curing step S103, the heating unit 15 in this state is moved by the relative moving unit together with the recoater in a direction B opposite to the direction A of movement above (directly above) the second metal powder layer 23, from the other end of the recess 11 toward one end, relative to the second metal powder layer 23, and then returned to its initial position. As a result, the second metal powder layer 23 is heated and the bonding fluid 24 is provisionally cured, thereby completing the second layer 102 of the intermediate shaped object 100 as shown in FIG. 4(D). Note that if the bonding fluid 24 has the property of being provisionally cured immediately without heating, or if natural drying is preferred, the provisional curing step by the heating unit 15 may be omitted.

[0054] When the second layer 102 of the intermediate product 100 is completed, the process proceeds to determination step S104, where it is determined whether all layers are completed. If a third layer is required, the process proceeds to NO, and the metal powder layer forming step S101 (see FIGS. 3(A) to 3(D)), the bonding fluid applying step S102 (see FIG. 4(A)), and the temporary curing step S103 (see FIGS. 4(B) and 4(C)) are performed again in this order to provide a third layer (not shown) that will be an upper layer adjacent to the second layer 102. Note that, as shown in FIG. 4(B), the case where the stage 17 is lowered by the elevator unit to the lower side of the recess 11 in the depth direction D before the temporary curing step S103 to provide the containing region 112 in the recess 11 has been exemplified. However, the stage 17 may be lowered after the temporary curing step S103.

[0055] By repeating the above steps, the layers of the intermediate model 100 are sequentially stacked, and if it is determined in the determination step S104 that all layers have been completed (YES), the process proceeds to the curing step S110.

[0056] <Curing process> In the curing step S110, the bonding fluid contained in the intermediate object 100 is completely hardened. The curing step is performed in a curing area W (curing space L) (see FIG. 5A) that is different from the printing area V (printing space K). The curing area W is an area that accommodates the intermediate object 100 and performs the curing process. The curing space L refers to the furnace space inside a curing oven (drying oven) that functions as the curing device 25, and includes the curing area W. In the curing process of this embodiment, the intermediate object 100 is heated at a predetermined temperature (e.g., 200°C) for a predetermined time. The predetermined temperature in the curing process is preferably 100°C or higher. As a result, the bonding fluid 24 contained in the intermediate object 100 dries and completely hardens. The curing process may be performed by other methods depending on the properties of the bonding fluid. Incidentally, the residual component of the bonding fluid contained in the intermediate object 100 after the hardening step S110 and before the sintering step S130 is preferably in the range of 1 to 6% by weight based on the intermediate object 100, and more preferably in the range of 1 to 4%.

[0057] 5(A) and 5(B), the transition from the modeling process S100 to the curing process S110 is achieved by moving the modeling tank 10 and stage 17 used in the modeling apparatus 1 together with the intermediate model 100 therein and the uncured titanium-containing metal powder 20 remaining around it from the modeling apparatus 1 to the curing apparatus 25. Note that, as shown in FIG. 5(A), in this embodiment, the modeling tank 10 has a recess 11 that accommodates the intermediate model 100 and the titanium-containing metal powder 20, and is configured to be portable.

[0058] 5(B), the curing device 25 has a temperature adjusting unit 27 that adjusts the temperature inside the furnace (the temperature of the curing space L) to a temperature at which the water-soluble bonding fluid contained in the intermediate object 100 can be dried and cured. The curing device 25 may be, for example, a thermostatic furnace, but is not limited to this and may be other devices.

[0059] Furthermore, in this embodiment, since uncured titanium-containing metal powder 20 is present even in the curing region W (curing space L), it is preferable to fill this curing region W (curing space L) with an inert gas to eliminate the risk of this titanium-containing metal powder 20 scattering and causing a dust explosion. Furthermore, during the transfer of the intermediate object 100 and titanium-containing metal powder 20 contained in the manufacturing tank 10 from the manufacturing apparatus 1 to the curing apparatus 25, the titanium-containing metal powder 20 is likely to scatter, which may result in ignition due to static electricity or the like, causing a dust explosion of the titanium-containing metal powder 20. Therefore, as shown in FIG. 5(A), it is preferable to create an inert gas atmosphere along a movement path 31 of the manufacturing tank 10 (the area surrounded by a dotted line in FIG. 5(A)) from the manufacturing apparatus 1 to the curing device 25 (curing region W) by providing a cover that covers the movement path 31 of the manufacturing tank 10. This cover separates the movement path 31 from the external space.

[0060] <Metal powder removal process> In the metal powder removal step S120, the uncured titanium-containing metal powder 20 remaining around the intermediate object 100 is removed. The metal powder removal step is performed in a powder removal area X, as shown in FIG. 5(A). The powder removal area X is an area that accommodates the intermediate object 100 and performs the metal powder removal process. The powder removal area X is an area separate from the fabrication area V and the hardening area W. The powder removal space M refers to the processing space inside the powder removal device 30 and includes the powder removal area X. The transition from the hardening step S110 to the metal powder removal step S120 is achieved by moving the fabrication tank 10 and stage 17 used in the hardening device 25 from the hardening device 25 to the powder removal device 30 together with the intermediate object 100 therein and the uncured titanium-containing metal powder 20 remaining around it, as shown in FIG. 5(A). In the powder removal region X, the intermediate product 100 is removed, and the unhardened titanium-containing metal powder 20 adhering to the intermediate product 100 is removed by spraying an inert gas onto the intermediate product 100 using a spray nozzle or by using a brush.

[0061] When removing the titanium-containing metal powder 20 from the intermediate object 100, there is a risk that the titanium-containing metal powder 20 may scatter and ignite due to static electricity or the like, resulting in a dust explosion. For this reason, the metal powder removal step S120 is preferably performed in an inert gas atmosphere. In this embodiment, it is particularly preferable that the powder removal region X where the powder removal process is performed is under an inert gas atmosphere. Desirably, the entire powder removal space M is under an inert gas atmosphere. The titanium-containing metal powder 20 removed in the metal powder removal step S120 is recovered and reused to form the three-dimensional object 200.

[0062] Furthermore, while the modeling tank 10 and the stage 17 are being moved from the curing device 25 (curing area W) to the powder removal area X where the metal powder removal process is performed, the titanium-containing metal powder 20 is likely to scatter, and there is a risk of the titanium-containing metal powder 20 igniting due to static electricity or the like, causing a dust explosion. For this reason, it is preferable to cover the movement path 32 of the modeling tank 10 and the like from the curing device 25 to the powder removal device 30 (the area surrounded by the dashed line in Figure 5(A)) to create an inert gas atmosphere by providing a cover that covers the movement path 32 of the modeling tank 10 and the like. This cover separates the movement path 32 from the external space.

[0063] As explained in each of the above steps, in order to eliminate the risk of dust explosion at all times while uncured titanium-containing metal powder 20 is present, it is preferable that each of the above steps (modeling step, curing step, metal powder removal step) and the movement paths 31, 32 between them be under an inert gas atmosphere as much as possible. Furthermore, the entire region 33 (see FIG. 5(A)) including the modeling apparatus 1, the curing apparatus 25, and the powder removal apparatus 30 may be collectively placed under an inert gas atmosphere. Furthermore, the inert gas used in each step may be the same type or different types.

[0064] Although the above example illustrates an inert gas atmosphere, all or part of the environment may be a vacuum environment (vacuum atmosphere). In the present invention, the vacuum environment (vacuum atmosphere) preferably has an oxygen concentration of 1.0% or less, more preferably 0.5% or less, and even more preferably 0.1% or less. To create a vacuum environment, a vacuum chamber is provided in each space (each region), and suction is performed using a vacuum pump.

[0065] <Sintering process> In the sintering step S130, the intermediate object 100 that has been subjected to the metal powder removing step S120 is sintered to produce a three-dimensional object 200. In this embodiment, for example, the intermediate object 100 is placed in a vacuum sintering furnace for sintering. The sintering temperature is preferably within a range of, for example, 1000°C to 1400°C, and more preferably 1200°C to 1400°C. Note that this sintering step includes a degreasing step for vaporizing and removing the binding fluid 24 (binder) that has hardened within the intermediate object 100.

[0066] When the intermediate object 100 is sintered, the particles that make up the intermediate object 100 bond together, causing the intermediate object 100 to shrink as a whole, resulting in a three-dimensional object 200. By increasing the sintering temperature, the density of the three-dimensional object 200 can be increased, so the sintering temperature is determined taking this into consideration.

[0067] <3D object> The three-dimensional object 200 will be described with reference to Figures 6 and 7. The three-dimensional object 200 in Figures 6 and 7 is formed along the stacking direction P. Figure 6(B) is an enlarged schematic diagram of the dotted line region F in the cross section of the three-dimensional object 200 taken along the stacking direction P and viewed from the arrow EE in Figure 6(A). The multiple minute regions in the schematic diagram depicted in Figure 6(B) are voids 210 formed inside the three-dimensional object 200.

[0068] As is clear from FIG. 6(B), the surface near-region H (see the outer shaded region in FIG. 6(A)) near the entire surface of the three-dimensional object 200, including the top layer G (the region above the dotted line) of the three-dimensional object 200 stacked in the modeling process S100, has a larger number of pores per unit volume than the core region I (see the inner shaded region in FIG. 6(A)) inside the three-dimensional object 200. The surface near-region H also has a higher porosity than the core region I. The porosity refers to the volume fraction of pores in a reference region (the surface near-region H or the core region I) included in the three-dimensional object 200, and can be expressed as (volume of pores / volume of the reference region (the surface near-region H or the core region I) included in the three-dimensional object 200). Therefore, the porosity in the surface near-region H can be expressed as (volume of pores in the surface near-region H / volume of the surface near-region H), and the porosity in the core region I can be expressed as (volume of pores in the core region I / volume of the core region I). During the sintering step S130, the bonding fluid 24 (binder) in each region of the intermediate object 100 moves to the outside through the surface of the three-dimensional object 200. Since the bonding fluid 24 (binder) in each region of the intermediate object 100 passes through the surface near-region H of the intermediate object 100, the density per unit volume of the bonding fluid 24 (binder) in the surface near-region H of the intermediate object 100 becomes higher during the sintering step than in other regions. As a result, in the surface near-region H of the intermediate object 100, many of the particles constituting the intermediate object 100 are bonded together with gaps between them. As a result, more pores 210 are formed in the surface near-region H of the three-dimensional object 200 than in other regions.

[0069] The surface near-region H of the three-dimensional object 200 includes not only the top layer of the intermediate object 100, which is stacked last in the modeling process S100 of this embodiment, but also regions near the surface of all other three-dimensional object 200. The depth (thickness) of the surface near-region H of the three-dimensional object 200 may be the same as or different from the depth (thickness) T of the top layer G of the three-dimensional object 200. Incidentally, in FIG. 6, the depth (thickness) of the surface near-region H of the three-dimensional object 200 is the same as the depth (thickness) T of the top layer G of the three-dimensional object 200.

[0070] Furthermore, stacking marks appear on the inclined surfaces 230 of the three-dimensional object 200 that has undergone the modeling process S100 of this embodiment, indicating the boundaries between adjacent layers. To illustrate this, FIG. 7B is a schematic enlarged view of the dotted-line region N including the inclined surfaces 230 in a cross section of the three-dimensional object 200 taken along the stacking direction P, as indicated by the arrow JJ in FIG. 7A. As shown in FIG. 7B, the inclined surfaces 230 of the three-dimensional object 200 are inclined with respect to the stacking direction P. Furthermore, the inclined surfaces 230 of the three-dimensional object 200 are not smoothly inclined. Instead, the layers 240 are stacked in the modeling process S100 of this embodiment, and the steps between adjacent layers 240 are formed in a continuous, stair-like manner along the inclination direction of the inclined surfaces 230. In other words, the layers 240 in the three-dimensional object 200 are formed such that the end faces 241 of adjacent layers 240 are offset from one another, resulting in steps between adjacent layers 240. This step becomes a layering mark on the three-dimensional object 200. [Example]

[0071] The inventors of the present application created three-dimensional objects from titanium-containing metal powder using a 3D printer device employing a binder jet method. In this case, a first three-dimensional object was created using pure titanium powder composed of titanium as the titanium-containing metal powder, and a second three-dimensional object was created using 64 titanium powder composed of Ti64 (Ti-6Al-4V) as the titanium-containing metal powder. The first three-dimensional object and the second three-dimensional object had the same shape and size. The pure titanium powder and the 64 titanium powder had a particle size range of 45 μm or less and an average particle size D 50The sintering temperature was 1200°C.

[0072] The inventors then measured the densities of the first and second three-dimensional objects that had undergone the sintering step, and the first intermediate object that had undergone the hardening step and the second intermediate object that had undergone the hardening step and corresponded to the first three-dimensional object. As a result, the density of the first intermediate object was found to be 2.55 g / cm. 3 The density of the second intermediate object is 2.55 g / cm 3 The density of the first 3D object is 4.24 g / cm 3 The density of the second 3D object is 4.16 g / cm 3 From the above results, the density of the intermediate object after the hardening process was 2.6 g / cm 3 The density of the three-dimensional object is 4.0 g / cm 3 As a result, the average particle size D 50 It was confirmed that high-density three-dimensional objects can be manufactured using pure titanium powder and 64 titanium powder with a particle size of 30 μm. Furthermore, the residual components of the binding fluid contained in the intermediate object after the hardening process and before the sintering process were approximately 3.5% by weight based on the intermediate object after the hardening process and before the sintering process.

[0073] Considering the above results, the density of the intermediate shaped object 100 after the hardening step and before the sintering step is 2.0 g / cm 3 It is preferable that the concentration is 2.2 g / cm or more. 3 More preferably, it is 2.5 g / cm or more. 3 It is more preferable that the density of the three-dimensional object 200 after the sintering step is 3.5 g / cm or more. 3 It is preferable that the concentration is 3.75 g / cm or more. 3 More preferably, it is 4.0 g / cm or more. 3 It is more preferable that the average particle diameter D of the titanium-containing metal powder, which is the material for the intermediate object 100 and the three-dimensional object 200, is equal to or larger than this. 50is preferably 40 μm or less.

[0074] The carbon concentration in the second three-dimensional object, based on the weight of the second three-dimensional object, was 0.0573 wt %. Considering this result, the carbon concentration in the three-dimensional object 200 is preferably 0.06 wt % or less.

[0075] The method for manufacturing a three-dimensional object of the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention. [Explanation of symbols]

[0076] 1 Modeling equipment 10 Modeling tank 11 Recess 12 Storage section 13 Roller 14 Combined fluid discharge part 15 Heating section 17 Stages 20 Titanium-containing metal powder 21 Metal powder layer (first metal powder layer) 22A Filled powder area 22B Excess powder area 23 Flat metal powder layer (second metal powder layer) 24 Bonding fluid (binder) 25 Curing equipment 30 Powder removal equipment 100 Intermediate object 101 First layer of intermediate model 102 Second layer of intermediate model 112 Containment Area 200 Three-dimensional sculpture

Claims

1. A manufacturing process in which a bonding fluid is applied to a metal powder containing titanium (hereinafter referred to as titanium-containing metal powder) in a manufacturing region to manufacture an intermediate object; a sintering step of sintering the intermediate object to produce a three-dimensional object; a hardening step of hardening the bonding fluid contained in the intermediate object in a hardening region different from the building region, after the building step and before the sintering step; Equipped with The manufacturing process is carried out under vacuum or an inert gas atmosphere, The curing step is carried out under vacuum or in an inert gas atmosphere. A method for manufacturing a three-dimensional object.

2. a moving path for moving the intermediate object that has undergone the modeling process from the modeling region to the hardening region is under a vacuum or an inert gas atmosphere; The method for manufacturing a three-dimensional object according to claim 1 .

3. a metal powder removing step of removing the titanium-containing metal powder adhering to a periphery of the intermediate shaped object after the hardening step and before the sintering step, The metal powder removal step is carried out under vacuum or in an inert gas atmosphere. The method for manufacturing a three-dimensional object according to claim 1 .

4. the metal powder removal step is carried out in a powder removal zone different from the hardening zone, a movement path along which the intermediate object that has undergone the hardening step is moved from the hardening region to the powder removal region is under a vacuum or an inert gas atmosphere. The method for manufacturing a three-dimensional object according to claim 3 .

5. In the manufacturing process, an oxygen concentration in the atmosphere is measured. The method for manufacturing a three-dimensional object according to claim 1 .

6. The average particle size D of the titanium-containing metal powder ５０ is 45 μm or less, The method for manufacturing a three-dimensional object according to claim 1 .

7. The average particle size D of the titanium-containing metal powder ５０ is 25 μm or more, The method for manufacturing a three-dimensional object according to claim 1 .

8. The density of the intermediate shaped object after the hardening step and before the sintering step is 2.0 g / cm ３ The above is characterized by the above. The method for manufacturing a three-dimensional object according to claim 1 .

9. The density of the intermediate shaped object after the hardening step and before the sintering step is 2.2 g / cm ３ The above is characterized by the above. The method for manufacturing a three-dimensional object according to claim 1 .

10. The density of the three-dimensional object after the sintering step is 3.5 g / cm ３ The above is characterized by the above. The method for manufacturing a three-dimensional object according to claim 1 .

11. The average particle size D of the titanium-containing metal powder ５０ is 40 μm or less, The density of the intermediate shaped object after the hardening step and before the sintering step is 2.5 g / cm ３ That's all, The density of the three-dimensional object after the sintering step is 4.0 g / cm ３ The above is characterized by the above. The method for manufacturing a three-dimensional object according to claim 1 .

12. the three-dimensional object after the sintering step contains 0.06 wt % or less of carbon based on the weight of the three-dimensional object. The method for manufacturing a three-dimensional object according to claim 1 .

13. The molding process includes: a metal powder layer forming step of supplying the titanium-containing metal powder to a region to be planar to form a metal powder layer; a bonding fluid application step of applying the bonding fluid to a partial region of the metal powder layer based on a planar shape of a plurality of layers (hereinafter referred to as "three-dimensional printing-side layers") obtained by dividing the three-dimensional object into the plurality of layers along a predetermined direction, thereby bonding the titanium-containing metal powder in the partial region to form a layer in the intermediate object (hereinafter referred to as "intermediate printing-side layer"); and the metal powder layer forming step and the bonding fluid applying step are repeatedly performed in order, whereby the intermediate modeling-side layers are sequentially stacked to provide the intermediate model. The method for manufacturing a three-dimensional object according to any one of claims 1 to 12.

14. a surface layer vicinity region including the uppermost three-dimensional modeling-side layer of the three-dimensional model stacked in the modeling step has a higher porosity than an inner core region; The method for manufacturing a three-dimensional object according to claim 13 .

15. the three-dimensional object has an inclined surface on its surface that is inclined with respect to a stacking direction of the plurality of three-dimensional object-forming side layers, the inclined surface is formed such that the steps between the adjacent three-dimensional modeling side layers are continuously formed in a step-like manner along the inclination direction, The step is a lamination mark representing a boundary between adjacent layers on the three-dimensional modeling side. The method for manufacturing a three-dimensional object according to claim 13 .

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