MOLDING PROCESS OF A LAMINATED BODY AND MOLDING DEVICE OF A LAMINATED BODY

Abstract

A molding process for a laminated body for molding a laminated body by blasting powder fed onto a support with a jet and melting and solidifying the powder or sintering the powder, wherein the molding process for the laminated body comprises: A movement distance adjustment step for setting a movement distance of the carrier to a length that represents a certain fraction of a particle diameter of the powder, wherein the movement distance is set based on the particle diameter of a particle; and a casting molding step for molding the laminated body by repeating a process of moving the carrier downwards by the movement distance, feeding the powder onto the carrier thus moved, and irradiating the fed powder with the jet to melt and solidify the powder or to sinter the powder.

Description

Field

[0001] The present invention relates to a method for molding a laminated body and a device for molding a laminated body. background

[0002] In recent years, a molding process for a laminated body has been put into practical application for casting a three-dimensional laminated body from a powdered raw material, such as metal powder. For example, patent literature 1 discloses a molding process for a laminated body using powder bed fusion technology, in which: a process of feeding metal powder into a powder feed chamber, irradiating a specific section of the metal powder with a laser beam to melt and solidify the specific section, and subsequently moving the powder feed chamber downwards; and the same process as this is repeated. Citation list for patent literature

[0003] Patent Literature 1: Japanese Patent Application Publication No. 2009-270130 Summary Technical Problem

[0004] When molding a laminated body using the powder bed fusion process, the mold conditions have a significant influence on the properties, such as the strength, of the laminated body. Therefore, it is necessary to adjust the mold conditions to prevent any impairment of the laminated body's properties.

[0005] The present invention was made to solve the problem described above, and an objective of the present invention is to provide a molding method for a laminated body and a molding device for a laminated body, each of which can prevent an impairment of the capabilities of a laminated body. Solution to the problem

[0006] To solve the problem described above and achieve the objective, a molding process for a laminated body according to the present disclosure serves to mold a laminated body by irradiating a powder fed onto a carrier with a jet and melting and solidifying or sintering the powder. The molding process for a laminated body includes: a movement distance setting step in which the movement distance of the carrier is set to a length corresponding to a certain fraction of the particle diameter of the powder; and a molding step for the laminated body by repeating a process in which the carrier is moved downwards by the movement distance, the powder is fed onto the moved carrier, and the fed powder is irradiated with the jet to melt and solidify or sinter the powder.

[0007] In this molding process for the laminated body, the movement distance is set based on the particle diameter of a particle, thus preventing any impairment of the laminated body's capabilities.

[0008] The molding process for the laminated body further includes a ratio acquisition step to acquire information about the ratio of the volume of a solidified body to the apparent volume of the powder fed onto the support, wherein the solidified body is formed as a result of irradiating the powder with the beam, and the movement distance can be adjusted based on the ratio in the movement distance setting step. This molding process for the laminated body prevents any impairment of the laminated body's capabilities.

[0009] In the movement distance setting step, the movement distance is preset to a length that is no less than 50% and no more than 100% of the maximum particle diameter of the powder. This molding process for the laminated body prevents any impairment of the laminated body's properties.

[0010] To solve the problem described above and achieve the objective, a molding process for a laminated body according to the present disclosure serves to mold a laminated body by irradiating powder fed to a carrier with a jet and melting and solidifying or sintering the powder. The molding process for a laminated body includes: a powder preparation step, in which the powder has a particle diameter that is a specific ratio to a movement distance of the carrier; and a molding step, in which the laminated body is molded by repeating a process of moving the carrier downwards by the movement distance, feeding the powder onto the moving carrier, and irradiating the fed powder with the jet to melt and solidify or sinter the powder.In this molding process of the laminated body, the laminated body is molded using powder that has a particle diameter in a specific ratio to the movement distance, thereby preventing impairment of the laminated body's capabilities.

[0011] The molding process for the laminated body preferably further includes a ratio acquisition step in which information about the ratio of the volume of a solidified body to the apparent volume of the powder fed onto the support is acquired, wherein the solidified body is formed as a result of irradiating the powder with the beam, the powder being prepared based on the ratio in the powder preparation step. This molding process for the laminated body prevents any impairment of the laminated body's properties.

[0012] The powder, which has a maximum particle diameter of no less than one and no more than two times the movement distance, is preferably prepared during the powder preparation step. This molding process for a laminated body prevents any impairment of the laminated body's properties.

[0013] To solve the problem described above and to achieve the objective, a molding device for a laminated body according to the present disclosure is configured to mold a laminated body by blasting powder fed onto a carrier with a jet and melting and solidifying or sintering the powder.The molding device for a laminated body comprises: a movement distance adjustment unit configured to set a carrier movement distance, based on the particle diameter of a particle, to a length that is a specific ratio to the particle diameter of the powder; and a molding unit configured to mold the laminated body by repeatedly moving the carrier downwards by the movement distance, feeding the powder onto the moving carrier, and blasting the fed powder with the jet to melt and solidify or sinter the powder. In this molding device for a laminated body, the movement distance is set based on the particle diameter of a particle, thus preventing any impairment of the laminated body's capabilities.

[0014] To solve the problem described above and achieve the objective, a molding device for a laminated body, as disclosed herein, is configured to mold a laminated body by irradiating powder fed to a carrier with a jet, melting and solidifying or sintering the powder. The molding device for a laminated body comprises: a powder preparation unit configured to prepare powder having a particle diameter in a specific ratio to a movement distance of the carrier; and a molding unit configured to mold the laminated body by repeatedly moving the carrier downwards by the movement distance, feeding the powder onto the moving carrier, and irradiating the fed powder with the jet to melt and solidify or sinter the powder.With this molding device for a laminated body, the laminated body is molded using powder that has a particle diameter in a specific ratio to the distance of travel, thereby preventing impairment of the capabilities of the laminated body. Advantageous effects of the invention

[0015] According to the present invention, impairment of the properties of the laminated body can be prevented. Brief description of the drawings Fig. Figure 1 is a schematic view of a molding device for a laminated body according to the present embodiment. Fig. Figure 2 is a schematic block diagram of a control system 20 according to the present embodiment. Fig. Figure 3 is a set of schematic views that illustrate a process for casting layers of solidified bodies sequentially. Fig. Figure 4 is a view to illustrate a condition in which powder has been stacked as a layer. Fig. Figure 5 is a schematic view showing the stacking of a layer according to a comparable example. Fig. Figure 6 is a schematic view showing the stacking of a layer according to the present embodiment. Fig. Figure 7 is a schematic view to illustrate the control procedure according to the present embodiment, which is carried out when the operation is stopped. Fig. Figure 8 is a flowchart that explains the process of molding a laminated body according to the present embodiment. Fig. Figure 9 is a flowchart to explain the process for molding a laminated body according to another example of the present embodiment. Fig. Figure 10 is a view showing images of the microstructure of a laminated body according to a comparable example. Fig. Figure 11 is a view showing images of the microstructure of a laminated body according to the present example. Description of the embodiments

[0016] A preferred embodiment of the present invention is described in detail below with reference to the accompanying drawings. This embodiment is not intended to limit the present invention. In a plurality of embodiments, the present invention includes an embodiment obtained by combining two or more of these embodiments.

[0017] Fig. Figure 1 is a schematic view of a molding device for a laminated body according to the present embodiment. The molding device 1 for a laminated body according to the present embodiment is a device capable of performing a molding process for a laminated body according to the present embodiment and is configured to mold a laminated body L, which is a three-dimensionally shaped object, from powder P using the so-called powder bed fusion technique. In the present embodiment, the powder P is a metal powder and can consist, for example, of a nickel-based alloy or a TiAl-based alloy. The present nickel-based alloy is an alloy containing Ni, Cr, Nb, and Mo, e.g., 50.0 to 55.0 wt.% Ni, 17.0 to 21.0 wt.% Cr, 4.75 to 5.50 wt.% Nb, and 2.8 to 3.3 wt.% Mo. This nickel-based alloy may contain unavoidable impurities.Inconel 718 (registered trademark) can be used as a nickel-based alloy. The present TiAl-based alloy is a compound (such as TiAl, Ti3Al, or Al3Ti) in which Ti and Al are bonded together, i.e., a TiAl-based intermetallic compound. For example, an alloy containing 40 to 50 atomic percent Al and 3 to 10 atomic percent Mn, with the remainder consisting of Ti and unavoidable impurities, can be used as the TiAl-based alloy. Alternatively, an alloy containing 40 to 50 atomic percent Al and at least one type of Cr and Nb selected for 3 to 10 atomic percent, with the remainder consisting of Ti and unavoidable impurities, can be used as the TiAl-based alloy.Each of the TiAl-based alloys of the compositions exemplified above may also contain at least one of the following elements: 1 to 2.5 at% Nb; at least one type selected from Mo, W, and Zr, comprising 0.2 to 1.0 at%; 0.1 to 0.4 at% C; and at least one type selected from Si, Ni, and Ta, comprising 0.2 to 1.0 at%. The laminated body L is cast from the powder P and is therefore formed into a metal body having the same composition as the powder P. However, the powder P and the laminated body L may have any compositions.

[0018] As in Fig. As shown in Figure 1, the molding device 1 for the laminated body comprises a molding chamber 10, a powder feed unit 12, a blade 14, a radiation source unit 16, a radiation unit 18, and a controller 20. Controlled by the controller 20, the molding device 1 for the laminated body feeds the powder P from the powder feed unit 12 to the molding chamber 10 and directs a beam from the radiation source unit 16 and the radiation unit 18 onto the powder P fed into the molding chamber 10, thereby melting and solidifying, or sintering, the powder P to form the laminated body L. Hereinafter, a direction directed vertically downwards from the top part is defined as direction Z1, and a direction opposite to direction Z1, i.e., a direction directed vertically upwards from the bottom part, is defined as direction Z2.

[0019] The casting chamber 10 comprises a housing 30, a support 32, and a movement mechanism 34. The housing 30 is an open-topped housing, i.e., the side facing direction Z2. The support 32 is positioned within the housing 30 so that it is surrounded by the housing 30. The support 32 is configured to be movable within the housing 30 in both directions Z1 and Z2. A space R, enclosed by the upper surface of the support 32 and the inner circumferential surface of the housing 30, serves as a space into which the powder P is fed. The movement mechanism 34 is connected to the support 32. Controlled by the controller 20, the movement mechanism 34 moves the support 32 vertically, i.e., in both directions Z1 and Z2.

[0020] The powder feed unit 12 is a mechanism that stores the powder P. The powder feed unit 12 is controlled by the controller 20 to feed the powder P, supplying it from a feed opening 12A into the chamber R on the carrier 32 under the control of the controller 20. The blade 14 is a scraper blade that horizontally scrapes the powder P supplied into the chamber R. The blade 14 is controlled by the controller 20.

[0021] The radiation source unit 16 is a radiation source for a beam B. The beam B is a bundle of particles or waves moving in parallel, in the present embodiment an electron beam. In the present embodiment, the radiation source unit 16 is a tungsten filament. However, the beam B is any beam capable of sintering or melting the powder P and is not limited to an electron beam, and the radiation source unit 16 can be any radiation source unit capable of emitting the beam B, e.g., the beam B can be a laser beam.

[0022] The irradiation unit 18 is positioned above the molding chamber 10, i.e., on the side facing Z2. The irradiation unit 18 is a mechanism that irradiates the molding chamber 10 with the beam B from the radiation source unit 16. The irradiation unit 18 includes, for example, optical elements such as an astigmatizing lens, a condenser lens, and a deflecting lens. The irradiation unit 18 includes, for example, a scanning mechanism that is controlled by the controller 20 to scan with the beam B and emit a beam onto a specific section of the powder P distributed over the entire carrier 32 by emitting the beam B from the radiation source unit 16 into the molding chamber 10 while scanning with the beam B. The powder P is melted and solidified (melted and then solidified) or sintered at the point where the beam B was emitted.Control unit 20 is described further below.

[0023] The molding device 1 of a laminated body is configured as described above. The molding device 1 of a laminated body feeds the powder P onto the carrier 32 by means of the powder feed unit 12 and emits the beam B onto the powder P on the carrier 32 by means of the radiation source unit 16 and the radiation unit 18. The powder P at the point where the beam B was emitted is sintered or melted and solidifies, becoming a solidified body A. After the solidified body A has been formed, the molding device 1 of a laminated body moves the carrier 32 by a distance H in the direction Z1 by means of the movement mechanism 34. The molding device 1 of a laminated body then feeds the powder P onto the carrier 32, i.e.The powder feed unit 12 directs the beam B onto the solidified body A and emits the beam B onto the powder P on the carrier 32 using the radiation source unit 16 and the radiation unit 18. As a result, another solidified body A is stacked as a layer on top of the solidified body A. After the new solidified body A has been stacked as a layer, the mold 1 of a laminated body moves the carrier 32 by the movement distance H in direction Z1 and repeats the same process. The mold 1 of the laminated body repeats this process to stack the solidified bodies A in layers and thereby form the laminated body L.

[0024] Fig. Figure 2 is a schematic block diagram of the controller 20 according to the present embodiment. The controller 20 is, for example, a computer and includes: an arithmetic processor, which consists of a central processing unit (CPU) or the like, and a memory unit. As shown in Figure 2, the controller 20 is a computer and includes: an arithmetic processor, which consists of a central processing unit (CPU) or the like, and a memory unit. Fig. As shown in Figure 2, the controller 20 includes a powder control unit 40, a radiation control unit 42, and a motion control unit 44. The powder control unit 40, the radiation control unit 42, and the motion control unit 44 are implemented by having a computer program that is read from the memory unit by the controller 20 and executes processes of the individual units. However, the powder control unit 40, the radiation control unit 42, and the motion control unit 44 can be separate hardware components.

[0025] The powder control unit 40 controls the supply of powder P to the carrier 32. For example, the powder control unit 40 controls the powder feed unit 12 to supply the powder P to the carrier 32, which has been moved downwards by the distance H. The powder control unit 40 then controls the blade 14 to cause the blade 14 to scrape the powder P off the carrier 32.

[0026] The radiation control unit 42 controls the radiation of beam B onto the powder P on the carrier 32. For example, the radiation control unit 42 reads three-dimensional data stored in the storage unit, sets a scanning path for beam B based on the three-dimensional data, and controls the radiation unit 18 to emit beam B along the set scanning path.

[0027] The motion control unit 44 controls the motion mechanism 34 to move the carrier 32. After the solidified body A has been formed with the jet B emitted onto the powder P, the motion control unit 44 moves the carrier 32 by the movement distance H in the direction Z1. Optionally, the motion control unit 44 can set a length of the movement distance H. The method for setting the movement distance H is described below.

[0028] Thus, each time the molding device 1 of the laminated body moves the carrier 32 downwards by the travel distance H, distributes the powder P over the entire carrier 32 and emits the jet B there, thereby stacking the solidified bodies A in layers one after the other to produce the laminated body L. Next, a process of molding from layers of the solidified bodies A one after the other is described.

[0029] Fig. Figure 3 is a series of schematic views illustrating a process for casting layers of solidified bodies sequentially. Step S10 in Fig. Figure 3 indicates a state in which the first layer is being stacked. The powder P is fed into the chamber R on the upper part of the carrier 32. The powder P is scraped off the blade 14, thereby filling the chamber R with powder P so that its top is flush with an upper end part 30A of the housing 30. Subsequently, each layer of powder P with which the chamber R has been filled is referred to as a powder layer S. The powder layer S is a layer with which the chamber R has been filled, but which contains voids because the powder layer S is formed with the powder P.

[0030] In the following, the length of space R in the direction of Z1, i.e. its height, is referred to as height HS.

[0031] The space R is filled with the powder layer S, and the height HS can therefore also be understood as the height of the powder layer S.

[0032] As by step S10 in Fig. As indicated in diagram 3, the height HS of chamber R is determined as a height HS1 when the first layer is stacked, and chamber R is filled with a powder layer S1, which is the first layer. The height HS1 of the first layer can be equal to the movement distance H. Beam B is emitted onto the powder layer S1, forming a solidified body A1. When beam B is emitted onto the powder layer S, the powder layer S is melted or sintered, reducing its apparent volume because voids within it disappear. The apparent volume, i.e., the volume of the powder layer S including the voids within it, is the total volume of the powder layer S, which includes the powder P and the voids. Therefore, the volume of the solidified body A is smaller than the apparent volume of the powder layer S, and the length, i.e., a height HA, of the solidified body A in the direction Z1 is smaller than the height HS of the powder layer S.In step S10, the solidified body A1, which has a height HA1, is formed from the powder layer S1 with a height HS1. In the present embodiment, the ratio between the height HA of the solidified body A and the height HS of the powder layer S is approximately 50%. In other words, the volume of the solidified body A is approximately 50% of the apparent volume of the powder layer S. Therefore, the height HA1 of the solidified body A1 in step S10 is less than the height HS1 of the powder layer S1 and is approximately 50% of the height HS1.

[0033] Step S12 in Fig. Figure 3 indicates a state in which the second layer is being stacked. After the solidified body A1 has been formed in step S10, the molding device 1 of the laminated body moves the carrier 32 by the travel distance H in the direction Z1 and then feeds the powder P into the space R on the top of the carrier 32, i.e., onto the solidified body A1. In this case, the distance between the top surface of the powder layer S1, stacked as the first layer, and the upper end part 30A of the housing 30 is the travel distance H. In reality, however, the powder layer S1 has been solidified into the solidified body A1. Therefore, the height HS2 of the space R, into which the powder P is fed, corresponds to the distance between the top surface of the solidified body A1 and the upper end part 30A of the housing 30. The height HS2 of the space R is greater than the height HS1 of the space R for the first layer.Specifically, the height HS2 of space R is determined by the difference between the height HA1 of the solidified body A1 and the height HS1 of the powder layer S1, and the downward movement distance H by which the carrier 32 is moved. This space R is then filled with the second powder layer S2, the height of which is also HS2. The beam B is emitted onto the powder layer S2, causing a solidified body A2 to form on top of the solidified body A1. The height of the solidified body A2 formed from the powder layer S2 is a height HA2. The height HA2 of the solidified body A2 is approximately 50% of the height HS2 of the powder layer S2 and is therefore higher than the height HA1 of the solidified body A1 for the first layer.

[0034] Step S14 in Fig. Figure 3 indicates a state in which the third layer is being stacked. After the solidified body A2 has been formed in step S12, the molding device 1 of the laminated body moves the carrier 32 by the distance H in the direction Z1 and then feeds the powder P into the chamber R on the top of the carrier 32, i.e., onto the solidified body A2. The height HS3 of the chamber R into which the powder P is fed corresponds to the distance between the top surface of the solidified body A2 and the upper end part 30A of the housing 30; therefore, the height HS3 is even greater than the height HS1 of the chamber R for the second layer. Specifically, the height HS3 of the chamber R is obtained by adding the difference between the height HA2 of the solidified body A2 and the height HS2 of the powder layer S2 to the distance H by which the carrier 32 is moved downwards. The height of the third powder layer S3, with which this space R is filled, is also the height HS3.Beam B is emitted onto powder layer S3, forming a solidified body A3 on top of the solidified body A2. The height of the solidified body A3 formed from powder layer S3 is a height HA3. The height HA3 of the solidified body A3 is approximately 50% of the height HS3 of powder layer S3 and is therefore higher than the height HA2 of the solidified body A2 for the second layer.

[0035] Also following step S14, a process of stacking one layer at a time of the solidified body A is repeated. After the stacking has been repeated a certain number of times, the height HS of space R (powder layer S) and the height HA of the solidified body A converge to specific values. Step S16 indicates a state in which the Nth layer is being stacked, where N is a specific number. As shown in step S16, when the Nth layer is stacked, space R on top of a solidified body AM, formed by stacking the Mth layer immediately preceding the Nth layer, is filled with a powder layer SN. Beam B is then emitted onto the powder layer SN, forming a solidified body AN on top of the solidified body AM. The height of space R at this step, i.e., a height HS, is... NThe powder layer SN is convergent and therefore corresponds to a height HSM of a powder layer SM that immediately precedes the powder layer SN. Likewise, a height HA N of the solidified body AN equal to a height HA M of the solidified body AM. The mold 1 of the laminated body generally stacks a large number of layers; therefore, a large part of the laminated body L is formed from the solidified bodies A after the convergence of these heights.

[0036] As described above, the solidified body A shrinks to a height approximately 50% of the height of the powder layer S. Therefore, the height HS N The powder layer SN (space R) in the N-th layer is expressed by equation (1) below. The term “HS (N-1) “In equation (1) expresses the height of the powder layer S immediately in front of the N-th layer, i.e. the height HS M the powder layer SM in Fig. 3. HSN=0.5⋅HS(N−1)+H

[0037] The height HS of the powder layer S after its convergence is expressed by the following equation (2), since the height HS N The powder layer SN is expressed by equation (1). HS=limn→∞ HSN=2H

[0038] This means that the height HS of the powder layer S after its convergence corresponds to twice the movement distance H. At the same time, the height ANS of the solidified body AN after its convergence essentially corresponds to the movement distance H, since the height ANS of the solidified body AN is approximately 50% of the height HS of the powder layer S.

[0039] The present inventors have addressed a process for stacking layers sequentially, as described above, and have discovered a technique intended to prevent impairment of the properties of the laminated body L. This technique associates the movement distance H of the carrier 32 for each layer with the particle diameters of the powder P when setting molding conditions. That is, the present inventors have discovered that setting the movement distance H to a specific fraction of a particle diameter of the powder P can prevent impairment of the properties of the laminated body L. This discovery is described in detail below.

[0040] Fig. Figure 4 is a view that explains a state in which a layer of powder has been stacked as a single layer. Fig. Figure 4 illustrates a state in which the solidified body A is formed from the powder layer S of the powder P. The powder P is an aggregate of a plurality of particles Po, which are, for example, metal particles (powder), wherein the aggregate comprises the particles Po combined within itself. In the molding device 1 of the laminated body, the height HS of the chamber R (powder layer S) is preferably not less than a maximum particle diameter Dmax of the particles Po in the powder P, i.e., set such that the particles Po corresponding to the maximum particle diameter Dmax can be contained in the chamber R, which has the height HS. In the present embodiment, the height HS of the chamber R (powder layer S), as expressed by equation (2), converges to a value that is twice the movement distance H.Therefore, if the value that is twice the movement distance H is not less than the maximum particle diameter Dmax, then the height HS cannot be kept smaller than the maximum particle diameter Dmax. In other words, if the movement distance H is not less than 50% of the maximum particle diameter Dmax, as expressed in expression (3) below, then the maximum particle diameter Dmax cannot be kept smaller than the height HS. H≥0.5⋅Dmax

[0041] Therefore, setting the movement distance H to no less than 50% of the maximum particle diameter Dmax can result in the heights HS in all layers after conversion being no less than 50% of the maximum particle diameter Dmax, because the height HS of space R (powder layer S) converges after stacking a layer has been repeated a certain number of times.

[0042] If the movement distance H is chosen to be too large, the thickness of the solidified body A becomes too great and the accuracy of the shaping decreases. Therefore, the movement distance H is preferably set relatively short. In the present embodiment, the movement distance H is preferably set so that it is, for example, no greater than 100% of the maximum particle diameter Dmax. That is, in the present embodiment, the movement distance H is preferably set no less than 50% and no greater than 100% of the maximum particle diameter Dmax. However, the present embodiment is not limited to setting the movement distance H to no more than 100%, since increasing the movement distance H is advantageous for accelerating the shaping process. Fig. Figure 4 shows an example of a case where the height HS is equal to the maximum particle diameter Dmax, i.e., a case where the movement distance H is 50% of the maximum particle diameter Dmax.

[0043] As described above, in the present embodiment, the solidified body A shrinks to a height that is 50% of the height of the powder layer S. This can be understood as meaning that the ratio of the height HA of the solidified body A to the height HS of the powder layer S is 0.5. However, it is also conceivable that the ratio between the height HA of the solidified body A and the height HS of the powder layer S is not 0.5. In such a case, the movement distance H can be determined based on a ratio X corresponding to the ratio of height HA to height HS. The height HS of the powder layer S can be expressed by equation (4) using the ratio X. The ratio X is a value less than 1. The ratio X between height HA and height HS can also be understood as the ratio between the volume of the solidified body A and the apparent volume of the powder layer S. HSN=(1−X)⋅HS(N−1)+H

[0044] Therefore, the height HS of the powder layer S after its convergence is expressed by the following equation (5). HS=limn→∞ HSN=HX

[0045] This means that the height HS of the powder layer S after its convergence corresponds to a value obtained by dividing the movement distance H by the ratio X. In this case, it can be understood that if the value obtained by dividing the movement distance H by the ratio X is not less than the maximum particle diameter Dmax, then the height HS cannot be kept smaller than the maximum particle diameter Dmax. Therefore, in this case, it can be assumed that the movement distance H need not be less than a value resulting from multiplying the maximum particle diameter Dmax by the ratio X, as given in expression (6). H≥X⋅Dmax

[0046] In the present embodiment, for example, the ratio X of height HA to height HS is approximately 50% when a nickel-based or TiAl-based alloy is used as the powder P. Therefore, for example, when a nickel-based or TiAl-based alloy is used for the powder P, the movement distance H is preferably set to not less than 50% and not more than 100% of the maximum particle diameter Dmax, as described above. However, the movement distance H cannot be less than 50% and not more than 100% of the maximum particle diameter Dmax even when neither a nickel-based nor a TiAl-based alloy is used as the powder P.Furthermore, the movement distance H, with a previously obtained value X of the ratio X of height HA to height HS, cannot be less than a value obtained by multiplying the maximum particle diameter Dmax by the ratio X, and cannot be more than 100% of the maximum particle diameter Dmax. The value of the ratio X can be determined by one of the following steps: actually producing the solidified body A from the powder layer S and measuring the value; calculating the value; and recording previously determined information.

[0047] Next, the effects are described in a case where the height HS of the space R (powder layer S) is set not less than the maximum particle diameter Dmax, i.e., the effects in a case where the movement distance H is set not less than a value obtained by multiplying the maximum particle diameter Dmax by the ratio X.

[0048] Fig. Figure 5 is a schematic view showing the stacking of a layer according to a comparable example. Fig. Figure 5 illustrates an example in which, when powder PX is fed onto a solidified body AX cast in a mold chamber 10X according to the comparable example, a space on the solidified body AX is filled with a layer of powder SX. In the comparable example, unlike the present embodiment, a movement distance of a carrier is not determined based on a particle diameter of the powder PX. Therefore, the comparable example may include a particle PoX whose particle diameter is larger than the height HSX of a space RX. In this case, the particle PoX with such a large particle diameter may protrude upwards from a top part 30AX of the mold chamber 10X and be removed, for example, during stripping.In this case, the powder layer SX might have a gap at the point from which the PoX particle was removed, or it might be relatively thin at that point. If the beam B is emitted onto this gap or onto a point where the layer is so thin, a relatively large amount of heat will be transferred to a portion of the solidified body AX beneath that point, and the temperature of the solidified body AX at that point will consequently become relatively high, potentially leading to a corresponding local reduction in the rate at which the molten powder layer SX cools during solidification.Such a local reduction in cooling rate could, for example, lead to the formation of crystalline phases at a location where the cooling rate has decreased, phases that differ from those formed elsewhere, potentially impairing the properties, such as strength, of a laminated body. For instance, if a nickel-based alloy is used, Laves phases may form at a location where the cooling rate has locally decreased, leading to a reduction in properties, such as strength, of a laminated body.

[0049] Fig. Figure 6 is a schematic view showing the stacking of a layer according to the present embodiment. Fig. Figure 6 illustrates an example in which a space on the solidified body A, cast in the mold chamber 10, is filled with a powder layer S using powder P, which is fed onto the solidified body A according to the present embodiment. The movement distance H of the carrier 32 according to the present embodiment is set based on the particle diameter of the powder P. More precisely, the height HS of the space R is not less than the maximum particle diameter Dmax of the powder P, since the movement distance H is set to a value that results from multiplying the maximum particle diameter PXo by the ratio X. In this case, the particles Po are prevented from protruding beyond the upper end part 30A, thus preventing the removal of the particles Po from the powder layer S.In the present embodiment, this prevents the formation of gaps in the powder layer S, thereby preventing a local decrease in the cooling rate. Consequently, in the present embodiment, for example, the formation of Laves phases is prevented, thus preventing any impairment of the properties of the laminated body. The present embodiment is also not limited to setting the height HS no greater than the maximum particle diameter Dmax of the powder P and can be any embodiment in which the movement distance H is set to a specific fraction of the particle diameter of the powder P.That is, in the present embodiment, adjusting the movement distance H based on a particle diameter of the powder P can not only prevent the formation of gaps, but also design a manufacturing process to prevent impairment of capabilities.

[0050] While in the present embodiment any method can be used to measure the particle diameters of the powder P, the particle diameters are obtained, for example, based on a particle size distribution measured using the laser diffraction and scattering method. A volume-based or a number-based distribution can be used as the particle size distribution. Fig. Figure 7 is a diagram to explain the particle diameters of particles. Fig. Figure 7 is a diagram that shows an example of the result of a particle diameter measurement. Fig. Figure 7 is an example of the measurement result of the particle size distribution of the powder P used for sampling, which was measured, for example, using the laser diffraction and scattering method. As in Fig. As shown in Figure 7, the maximum particle diameter Dmax of powder P, for example, represents the particle diameter of particle Po that has the largest diameter among the particles Po contained in the sampled powder P. However, the maximum particle diameter Dmax is not limited to being the particle diameter of particle Po with the largest diameter. For example, the maximum particle diameter could be defined as the particle diameter Dmax1 of a particle PO in the highest percentile, e.g., the highest 0.15th or highest 10th percentile, of the particles Po arranged in descending order of particle diameter. Alternatively, in the present embodiment, the movement distance H could, for example, be defined as a certain fraction of an average particle diameter D. AV of the powder P. In this case, the average particle diameter D is... AVthe average value of a particle size distribution, which was determined, for example, using the laser diffraction and scattering method.

[0051] Next, the casting process of the laminated body L according to the present embodiment will be described. Fig. Figure 8 is a flowchart illustrating the molding process of a laminated body according to the present embodiment. As shown in Fig. As shown in Figure 8, the controller 20 initially acquires information about the particle diameters of the powder P to be fed, for example, using the powder control unit 40 (step S10), and sets the movement distance H based on this acquired information about the particle diameters of the powder P using the motion control unit 44 (step S12; a movement distance setting step). The powder control unit 40 acquires, for example, the information about the particle diameters of the powder P, which is stored in the powder feed unit 12. This information about the particle diameters of the powder P indicates the value of a particle diameter of the powder P and is, for example, the value of the maximum particle diameter Dmax. The powder control unit 40 can, for example, use the information about the particle diameters of the powder P to determine the particle diameters of the powder P.The motion control unit 44 receives the information about the particle diameters of the powder P from the powder control unit 40, either through user input or as the result of measuring the particle diameters of the powder P using a particle size distribution measuring device (not shown). It then adjusts the motion distance H such that its ratio to a particle diameter of the powder P can be a predetermined ratio. For example, the motion control unit 44 adjusts the motion distance H such that it cannot be less than 50% and cannot be more than 100% of the maximum particle diameter Dmax of the powder P.Alternatively, the motion control unit 44 can detect the value of the ratio X of height HA to height HS and set the movement distance H such that its value cannot be less than a value obtained by multiplying the maximum particle diameter Dmax by the ratio X. Here, steps S10 and S12 are not limited to being implemented by the controller 20 but can be performed by the user. In this case, the user determines the movement distance H such that its ratio to a particle diameter P of the powder can be a predefined ratio and sets the movement distance H by entering such a determined value of the movement distance H into the controller 20.

[0052] Once the movement distance H is set, the controller 20 molds the laminated body L (step S24; a molding step). Each time the controller 20 moves the carrier 32 downwards by the movement distance H using the motion control unit 44, it feeds the powder P onto the carrier 32 using the powder control unit 40 and irradiates the powder P with the beam B, thereby stacking the solidified bodies A in layers to form the laminated body L. The current process ends here.

[0053] While the movement distance H in the present embodiment is set as described above based on a particle diameter of the powder P, the powder P to be used can be selected based on the preset movement distance H. That is, in the present embodiment, the powder P, which has a particle diameter whose ratio to the movement distance H of the carrier 32 corresponds to a preset ratio, can be prepared and used for molding the laminated body L. The ratio between the movement distance H and the particle diameter of the powder P is, in this case, the same as the ratio between them in a case where the movement distance H is set based on a particle diameter of the powder P.For example, the powder P to be used can be the powder P whose maximum particle diameter Dmax is no more than 200% (no more than twice) of the movement distance H, based on a modification of expression (3) above. Alternatively, the powder P to be used can be the powder P whose maximum particle diameter Dmax is a value obtained by dividing the movement distance H by the ratio X, based on a modification of expression (6) above. As a further alternative, the powder P whose maximum particle diameter Dmax is no less than 100% (no less than one time) of the movement distance H can be selected as the powder P to be used.

[0054] Fig. Figure 9 is a flowchart that explains the casting process of a laminated body according to another example of the present embodiment. Fig. Figure 9 illustrates the casting process of the laminated body L in a case where the powder P to be used is selected based on the movement distance H. As in Fig. As shown in Figure 9, the controller 20 acquires information about the preset movement distance H, for example, using the motion control unit 44 (step S30) at the beginning; and using the powder control unit 40, the controller 20 sets the particle diameter of the powder P to be used based on the acquired information about the movement distance H and prepares the powder P, which has the set particle diameters (step S32; a powder preparation step). For example, the powder control unit 40 calculates a particle diameter that has a specific ratio of the movement distance H. The powder control unit 40 then informs the user, for example, about the calculated particle diameter, to prompt the user to feed the powder P, which has the calculated particle diameter, thereby causing the powder feeder unit 12 to feed the powder P, which has the calculated particle diameter.Steps S30 and S32 are not limited to being executed by the controller 20, but can also be performed by the user. In this case, the user receives information about the preset movement distance H, calculates a particle diameter that is the specific ratio of the movement distance H, prepares the powder P, which has the calculated particle diameters, and instructs the powder feeder 12 to feed the prepared powder P.

[0055] The controller 20 then forms the laminated body L (step S34; a molding step). Each time the controller 20 moves the carrier 32 downwards by the movement distance H using the motion control unit 44, it feeds the powder P onto the carrier 32 using the powder control unit 40 and irradiates the powder P with the beam B, thereby stacking the solidified bodies A in layers to form the laminated body L. The present process ends here.

[0056] In the present embodiment, the movement distance H can be set based on the particle diameter of the powder P, or the powder P to be used can be selected based on the preset movement distance H. That is to say, in the present embodiment, the laminated body L is molded under conditions that allow the movement distance H to be a specific ratio to the particle diameter of the powder P.

[0057] As described above, the molding process of the laminated body according to the present embodiment is a molding process of the laminated body L by irradiating the powder P fed onto the carrier 32 with the beam B, thereby melting and solidifying or sintering the powder P, and includes a movement distance setting step and a molding step. In the movement distance setting step, the movement distance H of the carrier 32 is set to a length that represents a certain fraction of the particle diameter of the powder P. In the molding step, a process of moving the carrier 32 downwards by the movement distance H, feeding the powder P onto the carrier 32, and irradiating the fed powder P with the beam B is repeated to melt and solidify or sinter the powder P, thereby molding the laminated body L.This casting process of the laminated body can be carried out by the casting device 1 of the laminated body, for which the control 20, which serves as a movement distance setting unit and a casting unit, performs the movement distance setting step and the casting step.

[0058] In the molding process of the laminated body according to the present embodiment, the movement distance H is set to a length that is in a specific ratio to a particle diameter of the powder P; that is, the movement distance H is set based on a particle diameter of the powder P, thereby enabling the design of a manufacturing process to prevent any impairment of the properties of the laminated body L. Therefore, this molding process of the laminated body prevents any impairment of the properties of the laminated body L.

[0059] The molding process for the laminated body further includes a ratio acquisition step for acquiring information about the ratio X of the volume of a solidified body A to the apparent volume of the powder P fed onto the support 32, wherein the solidified body A is solidified as a result of irradiating the powder P with the beam B. The movement distance H is then set based on the ratio X in the movement distance setting step. In this molding process for the laminated body, the movement distance H is set based on the ratio X, thereby preventing any impairment of the capabilities of the laminated body L.

[0060] In the movement distance setting step, the movement distance H is set to a length that is not less than 50% and not more than 100% of the maximum particle diameter Dmax of the powder P. In this molding process for the laminated body, setting the movement distance H to not less than 50% and not more than 100% of the maximum particle diameter Dmax of the powder P prevents a reduction in the cooling rate because it prevents the formation of gaps in the powder layer S, thus preventing a reduction in dimensional accuracy. Therefore, this molding process for the laminated body prevents any impairment of the capabilities of the laminated body L.

[0061] Alternatively, the molding process of the laminated body according to the present embodiment is a method for molding the laminated body L by irradiating the powder P fed onto the support 32 with the beam B, thereby melting and solidifying or sintering the powder P, and comprises a powder preparation step and a molding step. In the powder preparation step, the powder P is prepared, having a particle diameter that is in a specific ratio to the movement distance H of the support 32. In the molding step, a process is repeated in which the support 32 is moved downwards by the movement distance H, the prepared powder P is fed onto the support 32, and the fed powder P is irradiated with the beam B to melt and solidify or sinter the powder P, thereby molding the laminated body L.This casting process of the laminated body can be carried out by the molding device 1 of the laminated body, for which the control 20, which serves as a movement distance setting unit and as a molding unit, performs the powder preparation step and the molding step.

[0062] In this molding process for the laminated body, the laminated body L is molded using powder P, which has a particle diameter that is a certain fraction of the movement distance H. That is, the powder P is selected based on the movement distance H, thus enabling the design of a manufacturing process to prevent impairment of the capabilities of the laminated body L. Therefore, this molding process for the laminated body can prevent any impairment of the capabilities of the laminated body L.

[0063] The molding process for the laminated body further includes a ratio acquisition step to acquire information about the ratio X of the volume of a solidified body A to the apparent volume of the powder P supplied to the support 32, wherein the solidified body A is solidified as a result of irradiating the powder P with the beam B. The powder P is then prepared in the powder preparation step based on the ratio X. In this molding process for the laminated body, the powder P is selected based on the ratio X, thereby preventing any impairment of the properties of the laminated body L.

[0064] In the powder preparation step, the powder P is prepared with a maximum particle diameter Dmax that is no more than twice the movement distance H. In this molding process for a laminated body, the maximum particle diameter Dmax is set to be no less than one and no more than twice the movement distance H, while preventing a reduction in the cooling rate. This prevents the formation of gaps in the powder layer S and thus avoids a reduction in dimensional accuracy. Therefore, this molding process for a laminated body prevents any impairment of the laminated body's capabilities L. Example

[0065] An example of the present embodiment is described below. For this example, an ARCAM-manufactured molding device for a laminated body, employing the electron beam melting (EBM) process, was used to mold a laminated body, with the movement distance H set to 50 µm. In this example, the laminated body was molded using powder obtained by gas atomization of a nickel-based alloy called Inconel 718, which was thereby pulverized. Regarding the maximum particle diameter of the powder in this example, the particle size distribution was measured using the laser diffraction and scattering method, and it was found that the maximum particle diameter is approximately 100 µm.In a comparable example, a laminated body was cast using powder that exhibited a maximum particle diameter of approximately 150 µm, as determined by measuring the particle size distribution using laser diffraction and scattering. In this comparable example, the conditions are the same as in the present example, except for the particle diameter.

[0066] Fig. Figure 10 is a view showing images taken of the microstructure of a laminated body according to a comparable example. Fig. Figure 11 is a view showing images of the microstructure of a laminated body according to the present example. The image W1X in the upper right corner in Fig. Figure 10 is an image of the microstructure of the laminated body according to the comparable example; and photograph W2X is an image obtained by enlarging a region enclosed by a rectangular frame in image W1X. Image W1 is located in the upper right corner of the image. Fig. Figure 11 is an image of the microstructure of the laminated body according to the present example; and photograph W2 is an image obtained by enlarging a region enclosed by a rectangular frame in image W1. As in Fig. As shown in Figure 10, the laminated body, according to the comparable example, has a location LA where a Laves structure has been deposited. As in Fig.In contrast to the example shown in Figure 11, the laminated body does not exhibit any Laves phases. It is therefore concluded that, according to the present example, the deposition of the Laves phase is prevented because the movement distance H is not less than 50% of the maximum particle diameter of the powder, thus preventing any impairment of its capabilities.

[0067] While one embodiment of the present invention is described above, the specifications described for this embodiment are not intended to limit other embodiments. The components described above include those that are readily conceivable to a person skilled in the art, those that are essentially identical, and those that fall within the so-called equivalence range. The components described above can be combined with one another in a suitable manner. Furthermore, various omissions, substitutions, or modifications to the components can be made without altering the core of the embodiment described above. List of reference symbols 1 MOLDING DEVICE FOR A LAMINATED BODY 10 MOLDING CHAMBER 12 POWDER FEEDING UNIT 14 BLADES 16 RADIATION SOURCE UNIT 18 RADIATION UNIT 20 CONTROL 30 HOUSINGS 32 CARRIERS 34 MOVABLE MECHANISM A solidified body B BEAM HA, HS HEIGHT L LAMINATED BODY P POWDER PO PARTICLES S POWDER LAYER

Claims

[1] A molding process for a laminated body for molding a laminated body by blasting powder fed onto a support with a jet and melting and solidifying or sintering the powder, wherein the molding process for the laminated body comprises: A movement distance adjustment step for setting a movement distance of the carrier to a length that represents a certain fraction of a particle diameter of the powder, wherein the movement distance is set based on the particle diameter of a particle; and a casting molding step for molding the laminated body by repeating a process of moving the carrier downwards by the movement distance, feeding the powder onto the carrier thus moved, and irradiating the fed powder with the jet to melt and solidify the powder or to sinter the powder. [2] A molding process for a laminated body according to claim 1, further comprising a proportion acquisition step for acquiring information about the proportion of a volume of a solidified body to an apparent volume of the powder supplied to the carrier, wherein the solidified body is solidified as a result of irradiating the powder with the beam, wherein the movement distance is set based on the ratio in the movement distance setting step. [3] A molding process for a laminated body according to claim 1 or 2, wherein in the movement distance setting step the movement distance is set to a length which is not less than 50% and not more than 100% of a maximum particle diameter of the powder. [4] A molding process for a laminated body by irradiating powder supplied to a carrier with a jet and melting and solidifying or sintering the powder, the molding process of the laminated body comprising the following: a powder preparation step for preparing the powder, which has a particle diameter that is a specific ratio to a movement distance of the carrier; and a casting step of the molding of the laminated body by repeating a process of moving the carrier downwards by the movement distance, feeding the powder onto the carrier thus moved, and irradiating the fed powder with the jet to melt and solidify the powder or to sinter the powder. [5] Casting method of a laminated body according to claim 4, further comprising a ratio sensing step between the volume of a solidified body and the apparent volume of the powder applied to the support, wherein the solidified body is solidified as a result of irradiating the powder with the jet, wherein the powder is prepared based on the ratio in the powder preparation step. [6] A molding process for a laminated body according to claim 4 or 5, wherein the powder, which has a maximum particle diameter of not less than one and not more than twice the movement distance, is prepared in the powder preparation step. [7] Molding device for a laminated body, configured for molding a laminated body by blasting powder supplied to a carrier with a jet and melting and solidifying or sintering the powder, wherein the device for molding the laminated body comprises: a movement distance setting unit configured to set a movement distance of the carrier, based on a particle diameter, to a length that has a specific ratio to a particle diameter of the powder; and A casting mold unit configured to mold the laminated body by repeatedly performing a process of moving the carrier downwards by the movement distance, feeding the powder onto the carrier thus moved, and blasting the fed powder with the jet to melt and solidify the powder or to sinter the powder. [8] Molding device for a laminated body, configured for molding a laminated body by irradiating powder supplied to a support with a jet and melting and solidifying the powder or sintering the powder, wherein the molding device for a laminated body comprises: a powder preparation unit configured to prepare powder having a particle diameter that is a specific ratio to a carrier movement distance; and A casting mold unit configured to mold the laminated body by repeatedly performing a process of moving the carrier downwards by the movement distance, feeding the powder onto the carrier thus moved, and blasting the fed powder with the jet to melt and solidify the powder or to sinter the powder.

Images