Powder processing apparatus, three-dimensional molding apparatus, powder production method and method for producing three-dimensional molding

Abstract

To obtain a powder processing apparatus capable of lowering impedance by including soft metal powder such as copper, aluminum or the like, by suppressing generation of contamination during processing more than ever.SOLUTION: A powder processing apparatus 10 includes at least a pair of electrodes 12a and 12b, a processing container 11 that encloses the space between at least the pair of electrodes 12a and 12b and accommodates metal powder, a stirring mechanism 14 that stirs the metal powder inside the processing container 11, a power supply 13 that applies a voltage between at least the pair of electrodes 12a and 12b, and a control unit 15 that controls the operation of the stirring mechanism 14 and the power supply 13. At least the inner peripheral surface of the processing container 11 is made of an insulating material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a powder processing apparatus that processes metal powder used in a three-dimensional modeling apparatus, a three-dimensional modeling apparatus, a powder manufacturing method, and a method for manufacturing a three-dimensionally shaped object. [Background technology]

[0002] Conventionally, there is known a 3D printing apparatus that irradiates an electron beam onto metal powder spread in a printing area, melting and solidifying the powder to form a 3D object. In such a 3D printing apparatus, a first powder layer is formed on the upper surface of a base plate installed in the printing area, and then an electron beam is irradiated thereon. A next powder layer is formed on top of the powder layer irradiated with the electron beam, and then an electron beam is irradiated thereon. The 3D printing apparatus repeatedly forms powder layers and irradiates the electron beam, thereby stacking the layers that make up the 3D object one by one, and forming the 3D object.

[0003] It is known that three-dimensional printing devices can cause the powder to become negatively charged during printing, causing the powder particles to repel each other and scatter, resulting in a phenomenon known as "smoking." The occurrence of this phenomenon can result in an improper powder layer being formed, potentially resulting in defective printing. Patent Document 1, which describes a technique for suppressing the occurrence of this phenomenon, discloses a technique for reducing the impedance of metal powder by subjecting the metal powder used in printing to a mechanical pretreatment process that changes the shape of oxides on the surface of the metal powder. The technique described in Patent Document 1 involves mechanical pretreatment, such as introducing existing metal powder into a jet mill and causing the metal powder to collide, or introducing existing metal powder and balls into a ball mill and causing the metal powder to collide with the balls, thereby changing the shape of oxides on the surface of the metal powder. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 059183 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 has the problem that when powders made of soft metals such as copper (Cu) or aluminum (Al) are mechanically collided, the powder particles aggregate and connect together, which deteriorates the flowability of the powder. Furthermore, the technology described in Patent Document 1 physically damages the powder, which increases the occurrence of contamination from the inside of the container or the ball, resulting in a problem of a large amount of contamination being contained in the powder after mechanical pre-treatment.

[0006] The present disclosure has been made in consideration of the above, and aims to provide a powder processing apparatus that can suppress the occurrence of contamination during processing compared to conventional methods and reduce impedance, including for powders of soft metals such as copper and aluminum. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the present disclosure provides a powder processing apparatus including at least one pair of electrodes, a processing vessel surrounding the space between the at least one pair of electrodes and containing metal powder, a stirring mechanism for stirring the metal powder inside the processing vessel, a power supply for applying a voltage between the at least one pair of electrodes, and a control unit for controlling the operation of the stirring mechanism and the power supply. At least the inner circumferential surface of the processing vessel is made of an insulating material. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to suppress the occurrence of contamination during processing compared to conventional methods, and to reduce impedance by including powder of soft metals such as copper and aluminum. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 1 is a diagram schematically illustrating an example of the configuration of a powder processing apparatus according to a first embodiment. [Figure 2] A cross-sectional view showing a schematic example of the structure of a powder used in a three-dimensional modeling device. [Figure 3] FIG. 1 is a diagram for explaining the principle of a powder manufacturing method according to the first embodiment. [Figure 4] Diagram showing the equivalent circuit of Figure 3 [Figure 5] 1 is a flowchart showing an example of a processing procedure of a powder manufacturing method according to the first embodiment. [Figure 6] FIG. 10 is a diagram schematically illustrating another example of the configuration of the powder processing apparatus according to the first embodiment. [Figure 7] FIG. 1 is a diagram showing an example of the hardware configuration of a control unit of a powder processing apparatus according to embodiment 1. [Figure 8] FIG. 10 is a diagram schematically illustrating an example of the configuration of a powder processing apparatus according to a second embodiment. [Figure 9] 10 is a flowchart showing an example of a processing procedure of a powder manufacturing method according to a second embodiment. [Figure 10] FIG. 10 is a diagram schematically illustrating an example of the configuration of a three-dimensional modeling apparatus according to a third embodiment. [Figure 11] 10 is a flowchart showing an example of a processing procedure for manufacturing a three-dimensional object according to a third embodiment. [Figure 12] FIG. 10 is a block diagram showing an example of the hardware configuration of a control device included in the additive manufacturing apparatus according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A powder processing apparatus, a three-dimensional modeling apparatus, a powder manufacturing method, and a three-dimensional model manufacturing method according to embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0011] Embodiment 1 1 is a diagram schematically illustrating an example of the configuration of a powder processing apparatus according to embodiment 1. The powder processing apparatus 10 includes a processing container 11, at least one electrode pair 12, a power source 13, a stirring mechanism 14, and a control unit 15.

[0012] The processing vessel 11 is a vessel capable of accommodating powder 50 used in a three-dimensional modeling apparatus, which will be described later, and at least the inner circumferential surface of which is made of an insulating material. One example of the processing vessel 11 is an insulating vessel made of an insulating material. The processing vessel 11 is also a vessel that surrounds at least one electrode pair 12, i.e., the space between at least one pair of electrodes 12a and 12b. The processing vessel 11 may have any shape, such as a cylindrical shape or a rectangular tubular shape.

[0013] The processing vessel 11 has an opening on its side through which the powder 50 can be introduced and removed, and a lid 111 that covers the opening and can be opened and closed. By opening the lid 111, the powder 50 can be introduced and removed from the processing vessel 11 through the opening. The powder 50 contained in the processing vessel 11 is a powder used for 3D printing using a three-dimensional printing apparatus, and has an insulating outer layer formed by an oxide film and a conductive inner layer. In one example, the powder 50 is a powder whose inner layer is made of a metal element or alloy and whose outer layer is made of a metal element or alloy and whose inner surface is made of an oxidized oxide film. Furthermore, the metal powder in the claims corresponds to the powder 50, i.e., a powder whose inner layer is made of a metal element or alloy and whose outer layer is made of a metal element or alloy and whose inner surface is made of an oxidized oxide film.

[0014] At least one electrode pair 12 is provided inside the processing vessel 11. Each electrode pair 12 includes an electrode 12a and an electrode 12b. FIG. 1 illustrates an example in which electrodes 12a and 12b are provided on each of two bottom surfaces inside the cylindrical processing vessel 11, but the arrangement of electrodes 12a and 12b is not limited thereto. In one example, electrodes 12a and 12b may be provided on one of the two bottom surfaces inside the cylindrical processing vessel 11 and on a side surface, respectively. FIG. 1 also illustrates an example in which one electrode pair 12 is provided inside the processing vessel 11, but two or more electrode pairs 12 may be provided inside the processing vessel 11. Note that, for simplicity of explanation, the following description will be given assuming that the powder processing apparatus 10 has one electrode pair 12.

[0015] Power supply 13 is connected to electrode pair 12 by wiring so as to apply a voltage between electrodes 12a and 12b constituting at least one electrode pair 12. Power supply 13 may be a DC power supply or an AC power supply. In the example of FIG. 1, power supply 13 is assumed to be a DC power supply. Power supply 13 switches on and off the voltage applied between at least one electrode pair 12 in accordance with instructions from control unit 15.

[0016] Stirring mechanism 14 is a mechanism that stirs powder 50 inside processing vessel 11. In FIG. 1, a rotation mechanism that rotates processing vessel 11 about an axis connecting the centers of the two bottom surfaces of cylindrical processing vessel 11 is provided as stirring mechanism 14. In this case, the rotation mechanism has a rotation shaft (not shown) fixed to the center of the bottom surface of processing vessel 11 and a drive unit (not shown) that drives the rotation shaft. Stirring mechanism 14 switches rotation on and off according to instructions from control unit 15.

[0017] The control unit 15 controls the operation of the power supply 13 and the stirring mechanism 14. When the powder 50 is placed in the processing vessel 11, the control unit 15 applies a voltage between the pair of electrodes 12a and 12b and operates the stirring mechanism 14 so that the impedance of the powder 50 inside the processing vessel 11 falls within a predetermined range. In one example, the control unit 15 applies a predetermined voltage between the pair of electrodes 12a and 12b so that the impedance of the powder 50 disposed between the pair of electrodes 12a and 12b falls within the predetermined range. At this time, whether the impedance of the powder 50 falls within the predetermined range may be determined by measuring the impedance of the powder 50 disposed between the pair of electrodes 12a and 12b. Alternatively, whether the impedance of the powder 50 falls within the predetermined range may be determined by applying a voltage between the pair of electrodes 12a and 12b for a predetermined first period that is experimentally determined so that the impedance of the powder 50 disposed between the pair of electrodes 12a and 12b falls within the predetermined range. The control unit 15 causes the stirring mechanism 14 to stir the powder 50 when the impedance between the pair of electrodes 12a, 12b falls within a predetermined range or when a voltage is applied between the pair of electrodes 12a, 12b for a first period. The control unit 15 then continues applying voltage and stirring the powder 50 until a predetermined second period has elapsed since the start of voltage application and stirring of the powder 50, or until the voltage application and stirring of the powder 50 have been performed a predetermined number of times. In other words, the control unit 15 controls the stirring mechanism 14 and the power source 13 so that the voltage application and stirring of the powder 50 are alternately performed. In another example, the control unit 15 may operate the stirring mechanism 14 while applying a predetermined voltage between the pair of electrodes 12a, 12b. In this way, the control unit 15 controls the stirring mechanism 14 and the power source 13 so that the voltage application and stirring of the powder 50 are simultaneously performed.

[0018] Here, a powder manufacturing method using the powder processing apparatus 10 will be described. FIG. 2 is a cross-sectional view schematically illustrating an example of the structure of a powder used in a three-dimensional modeling apparatus. As described above, the powder 50 is composed of a metal element or alloy and has an oxide film formed on the inner surface. Therefore, the powder 50 is usually conductive immediately after production, specifically when no oxide film is formed. However, when used in a three-dimensional modeling apparatus, a thin insulating oxide film 52 is often formed on the surface of the powder 50. That is, as shown in FIG. 2, the powder 50 has a conductive center 51 and an insulating oxide film 52 that surrounds the center 51 in a shell-like shape. When such powder 50 is irradiated with an electron beam, the electron beam penetrates to the center 51. As a result, the center 51 becomes charged, but the charge is trapped by the oxide film 52. In other words, the oxide film 52 prevents electricity from flowing, and the powder 50 becomes charged.

[0019] By distorting the oxide film 52 of the charged powder 50 in this way, it is possible to make it easier for electricity to flow. Distorting the oxide film 52 can be likened to creating a crack in the oxide film 52 of FIG. 2. Possible methods for distorting the oxide film 52 of the powder 50 include mechanical methods and electrical methods. In the first embodiment, the oxide film 52 of the powder 50 is distorted by an electrical method.

[0020] FIG. 3 is a diagram illustrating the principle of the powder manufacturing method according to the first embodiment. FIG. 4 is a diagram illustrating an equivalent circuit of FIG. 3. Here, two powder particles 50a, 50b are assumed to be present between a pair of electrodes 12a, 12b. When a DC voltage is applied between the pair of electrodes 12a, 12b sandwiching the powder particles 50a, 50b having a shell-shaped oxide film 52, a capacitance component appears as shown in FIG. 4. That is, a capacitor C1 is formed between the electrode 12a and the center 51 of the powder 50a, a capacitor C2 is formed between the center 51 of the powder 50a and the center 51 of the powder 50b, and a capacitor C3 is formed between the center 51 of the powder 50b and the electrode 12b. By increasing the voltage applied to the capacitors C1, C2, and C3, the force pressing the powder particles 50a, 50b together increases, causing a large distortion in the oxide films 52 of the powder particles 50a, 50b, and making the powder particles 50a, 50b having the oxide film 52 conductive. That is, compared to the powders 50a and 50b before treatment, current flows more easily, that is, the impedance is lowered.

[0021] If the voltage applied to the capacitors C1, C2, and C3 is too low, it is difficult to distort the oxide film 52. For this reason, it is necessary to apply to the capacitors C1, C2, and C3 a voltage large enough to distort the oxide film 52. The minimum voltage value applied to the capacitors C1, C2, and C3 that can distort the oxide film 52, i.e., the minimum voltage value applied to each powder 50, is referred to as the first threshold value.

[0022] Furthermore, as the voltage applied to the capacitors C1, C2, and C3 increases, the oxide films 52 of the two powders 50a and 50b are crushed at a certain voltage. In one example, the oxide film 52 breaks, the center 51 pops out, and the powders 50a and 50b stick together. In this state, the powders 50a and 50b become conductive, but they no longer have the proper properties of powder 50a and 50b, and therefore cannot be used as raw materials in a three-dimensional printing apparatus. The minimum voltage value applied to the capacitors C1, C2, and C3 at which the powders 50a and 50b stick together, i.e., the minimum voltage value applied to each powder 50a and 50b at which the oxide films 52 on the surfaces of the adjacent powders 50a and 50b are broken, is referred to as the second threshold value.

[0023] As described above, in the first embodiment, the voltage between the pair of electrodes 12a, 12b is determined so that the voltage applied to each of the powders 50 between the pair of electrodes 12a, 12b is greater than the first threshold value and less than the second threshold value. Note that the voltage applied to each powder 50 differs depending on the type of material of the powder 50, and is determined in advance by experiment.

[0024] The voltage applied between the pair of electrodes 12a, 12b varies depending on the size of the processing vessel 11, more specifically, the distance between the pair of electrodes 12a, 12b, and the type of material of the powder 50 being processed. Therefore, the first and second thresholds are determined in advance by experimentation for each combination of the powder processing apparatus 10 and the type of material of the powder 50 to be processed. The voltage applied between the pair of electrodes 12a, 12b when the powder production method is performed using the actual powder processing apparatus 10 is a voltage determined so that a voltage between the first and second thresholds is applied to each of the powders 50 between the pair of electrodes 12a, 12b. For example, when the powder 50 is titanium (Ti), applying a voltage of 20 V per powder 50 can distort the oxide film 52.

[0025] In FIG. 1 , the powder 50 with a bold outline 50P is the powder with a distortion imparted to the oxide film 52. Hereinafter, the powder 50P with a distortion imparted to the oxide film 52 is also referred to as the processed powder 50P. The connection between the processed powders 50P forms a current path. After the current path is formed, even if a voltage is continuously applied between the pair of electrodes 12a and 12b, current flows only through the formed current path. Therefore, the oxide film 52 of the powder 50 other than the processed powder 50P forming the current path cannot be distorted. Therefore, once the current path is formed, the stirring mechanism 14 stirs the powder 50 inside the processing vessel 11, and the process of applying a voltage between the pair of electrodes 12a and 12b is repeated. This allows distortion to be imparted to the oxide film 52 of new powder 50. In the example shown in FIG. 1 , stirring is performed by rotating the processing vessel 11, significantly reducing the possibility of contamination being introduced into the powder 50 due to stirring, as in conventional techniques. Furthermore, the treated powder 50P maintains a reduced impedance even after the voltage between the pair of electrodes 12a, 12b is removed.

[0026] Although the above description has been given with reference to an example in which a DC voltage is applied, the same applies when an AC voltage is applied. However, with an AC voltage, the polarity of the voltage applied between the pair of electrodes 12a and 12b is periodically reversed, causing the powder 50 between the pair of electrodes 12a and 12b to vibrate. That is, while the AC voltage is being applied, the position of the powder 50 between the pair of electrodes 12a and 12b changes, causing a current path that was once formed to disappear and a current path to be formed at another position. Therefore, when the voltage is applied for the same time, applying an AC voltage can impart distortion to the oxide film 52 of a larger number of powders 50 than when applying a DC voltage. Alternatively, by extending the time between stirring sessions, it is possible to impart distortion to the oxide film 52 of a larger number of powders 50. In other words, applying an AC voltage can impart distortion to the oxide film 52 more efficiently than applying a DC voltage.

[0027] Furthermore, in the above explanation, a case where voltage application and stirring are performed alternately is shown, but in one example, the average time or maximum time from when a voltage is applied between the pair of electrodes 12a, 12b until a current path is formed is calculated, and the stirring speed during this time is set to a speed at which the powder 50 does not move, or in the example of FIG. 1, the rotation speed, so that voltage application and stirring can be performed simultaneously.

[0028] 5 is a flowchart showing an example of a processing procedure of the powder manufacturing method according to embodiment 1. First, the lid 111 of the processing container 11 of the powder processing apparatus 10 is opened, and the powder 50 is introduced into the processing container 11 through the opening thereof (step S11). The process of step S11 corresponds to a powder introducing process.

[0029] After closing the lid 111, the control unit 15 controls the power supply 13 to apply a voltage between at least one pair of electrodes 12a, 12b (step S12). The voltage to be applied is determined so that the voltage applied to one powder 50 is between the first threshold and the second threshold, as described above, and the determined voltage is set in the power supply 13. Here, the voltage is applied for a predetermined first period. The first period is determined depending on the type of material of the powder 50, and in one example, is determined in advance by experiment. The process of step S12 corresponds to the voltage application process.

[0030] Next, the control unit 15 controls the stirring mechanism 14 to stir the powder 50 inside the processing vessel 11 by the stirring mechanism 14 (step S13). The process of step S13 corresponds to a stirring process.

[0031] Thereafter, it is determined whether the termination condition for the powder production process has been satisfied (step S14). The termination condition for the powder production process is whether a predetermined second period has elapsed since the start of the process, or whether a predetermined number of voltage application steps and stirring steps have been performed. These termination conditions for the powder production process are conditions for determining whether distortion has been imparted to the oxide film 52 for almost all of the powder 50 inside the processing vessel 11. The termination condition for the powder production process differs depending on the type of material of the powder 50, the size of the processing vessel 11, and the amount of powder 50 placed in the processing vessel 11, and is therefore determined in advance by experiment.

[0032] If the termination condition for the powder production process is not satisfied (No in step S14), the process returns to step S12. Then, steps S12 to S14 are executed until the termination condition for the powder production process is satisfied. In other words, the voltage application step in step S12 and the stirring step in step S13 are executed alternately.

[0033] Furthermore, if the termination condition for the powder production process is met (Yes in step S14), processed powder 50P with distortion imparted to oxide film 52 has been produced, and lid 111 of processing vessel 11 is opened, and processed powder 50P is discharged from the interior of processing vessel 11 through the opening (step S15). Processed powder 50P produced in this manner can be used as is as a raw material in a three-dimensional modeling device, or, for example, can be stored in an inert atmosphere such as argon (Ar) gas or nitrogen (N) gas. This completes the powder production process.

[0034] 5, the voltage application process of step S12 and the stirring process of step S13 are performed alternately, but the voltage application process of step S12 and the stirring process of step S13 may be performed simultaneously. That is, the powder 50 inside the processing vessel 11 may be stirred while applying a voltage.

[0035] In FIG. 1, the powder 50 is agitated by rotating the processing vessel 11 around the rotation axis, but the powder 50 can also be agitated by other methods. FIG. 6 is a diagram schematically illustrating another example of the configuration of the powder processing apparatus according to the first embodiment. The same components as those in FIG. 1 are denoted by the same reference numerals, and their description will be omitted. The powder processing apparatus 10A shown in FIG. 6 illustrates an example in which agitation is performed by rotation of a propeller 145 provided inside the processing vessel 11. In this example, the agitation mechanism 14 includes the propeller 145 provided inside the processing vessel 11, a rotation shaft 146 that rotates the propeller 145, and a drive unit 147 that rotates the rotation shaft 146. The propeller 145 is preferably provided in a position where it is hidden by the powder 50 when the powder 50 is contained inside the processing vessel 11. In this example, the driving unit 147 is provided at the top vertically inside the processing vessel 11, and the propeller 145 is provided at the bottom vertically, but the propeller 145 may be provided at any position as long as it is a position where the propeller 145 can stir the powder 50.

[0036] Furthermore, at least the surfaces of propeller 145 and rotating shaft 146 are made of an insulating material. At least the surface of propeller 145 is desirably made of the same component as oxide film 52 of powder 50. As a result, even when powder 50 is agitated by the rotation of propeller 145, the contamination generated will be the same component as oxide film 52 of powder 50, and therefore the generation of contamination is substantially suppressed.

[0037] The stirring by the propeller 145 changes the position of the powder 50, and does not require vigorous stirring. In other words, the rotation speed of the propeller 145 can be kept low. This type of stirring can prevent contamination from occurring due to physical contact between the propeller 145 and the powder 50. For this reason, the material of the propeller 145 does not have to be the same as the oxide film 52 of the powder 50, and may be an insulating material.

[0038] Here, the hardware configuration of the control unit 15 of the powder processing apparatus 10, 10A will be described. Figure 7 is a diagram showing an example of the hardware configuration of the control unit of the powder processing apparatus according to embodiment 1.

[0039] The control unit 15 can be realized by a control circuit 400 shown in Fig. 7, that is, a processor 401 and a memory 402. An example of the processor 401 is a central processing unit (also called a CPU (Central Processing Unit), processing unit, arithmetic unit, microprocessor, microcomputer, processor, or DSP (Digital Signal Processor)) or a system LSI (Large Scale Integration). An example of the memory 402 is a RAM (Random Access Memory) or a ROM (Read Only Memory).

[0040] The functions of the control unit 15 are realized by the processor 401 reading and executing a control program stored in the memory 402, which is a program for executing processing in the control unit 15. This control program can also be said to cause a computer to execute a control method for the powder processing apparatus 10, 10A in the control unit 15. The control program executed by the control unit 15 has a modular configuration in which the on / off control of the power supply 13 and the operation control of the stirring mechanism 14 are modularized, and these programs are loaded into the main storage device and generated on the main storage device.

[0041] The memory 402 is also used as a temporary memory when the processor 401 executes various processes.

[0042] The control program executed by the processor 401 may be provided as a computer program product stored in a computer-readable storage medium as an installable or executable file. Alternatively, the control program executed by the processor 401 may be provided to the control unit 15 of the powder processing apparatus 10, 10A via a network such as the Internet.

[0043] The control unit 15 may be realized by dedicated hardware. Alternatively, some of the functions of the control unit 15 may be realized by dedicated hardware, and some may be realized by software or firmware.

[0044] The powder processing apparatus 10, 10A according to the first embodiment includes at least one pair of electrodes 12a, 12b, a processing vessel 11 that encloses at least the space between the at least one pair of electrodes 12a, 12b and contains powder 50, a stirring mechanism 14 that stirs the powder 50 inside the processing vessel 11, a power source 13 that applies a voltage between the at least one pair of electrodes 12a, 12b, and a control unit 15 that controls the operation of the stirring mechanism 14 and the power source 13. Furthermore, at least the inner circumferential surface of the processing vessel 11 is made of an insulating material. In the powder processing apparatus 10, 10A, applying a voltage between the at least one pair of electrodes 12a, 12b forms a current path in a portion of the powder 50 present between the at least one pair of electrodes 12a, 12b, thereby reducing the impedance of the powder 50 at the location where the current path is formed. Furthermore, stirring the powder 50 with the stirring mechanism 14 changes the formed current path, ultimately resulting in a processed powder 50P in which the impedance of the majority of the powder 50 contained in the processing vessel 11 is reduced. In this way, since the powder 50 is not mechanically crushed, even soft metals such as copper and aluminum do not agglomerate, and the impedance can be reduced. Furthermore, the reduction in the impedance of the powder 50 makes it possible to avoid the occurrence of the smoke phenomenon when the powder 50 is used as a raw material in a three-dimensional modeling process and is irradiated with an electron beam.

[0045] When the processing vessel 11 is rotated as shown in FIG. 1, the powder 50 is not crushed as in the ball mill of Patent Document 1, and the powder 50 is not accelerated as in the jet mill. This effectively prevents contamination due to ball or wall collisions. Furthermore, when the propeller 145 is rotated to agitate the powder 50 as shown in FIG. 6, the powder 50 is stirred at a speed fast enough to change the position of the powder 50. This effectively prevents contamination from the propeller 145 due to contact between the propeller 145 and the powder 50, compared to the case of Patent Document 1. Furthermore, by using a material for the propeller 145 and the rotating shaft 146 that has the same composition as the oxide film 52 formed on the surface of the powder 50 to be produced, the fine particles generated by contact between the propeller 145 and the powder 50 have the same composition as the oxide film 52, thereby substantially preventing contamination. As described above, the powder processing apparatus 10, 10A according to the first embodiment can suppress the occurrence of contamination during processing compared to conventional apparatuses, and can reduce impedance including for powder 50 of soft metals such as copper and aluminum.

[0046] Furthermore, the technology described in Patent Document 1 involves mechanical pretreatment using a jet mill, ball mill, or the like to physically collide powder particles 50 together, resulting in a slow processing speed for the powder 50. This means that the time required for mechanical pretreatment is long for the entire powder 50 to be processed. The processing speed varies depending on factors such as the size of the processing vessel 11, but ball mills typically achieve processing speeds slower than 100 cc / h. On the other hand, with the powder processing apparatus 10, 10A according to the first embodiment, the time required to distort the oxide film 52 of the powder 50 is at most about 100 msec. The number of powder particles 50 that can be processed at one time is the number of particles that form the current path between the pair of electrodes 12a, 12b. Therefore, the average time required to distort the oxide film 52 of one powder particle 50 can be shorter than with mechanical processing. As a result, the processing speed of the powder processing apparatus 10, 10A according to the first embodiment can be set to 100 cc / h or more, thereby shortening the time required to produce powder particles 50 with distorted oxide films 52 compared to the technology described in Patent Document 1.

[0047] Embodiment 2 8 is a diagram schematically illustrating an example of the configuration of a powder processing apparatus according to embodiment 2. The same components as those described in embodiment 1 are denoted by the same reference numerals, and their description will be omitted. The powder processing apparatus 10B according to embodiment 2 further includes an impedance measuring unit 16 and a switching unit 17.

[0048] The impedance measuring unit 16 measures the impedance between at least the pair of electrodes 12 a, 12 b. In one example, the impedance measuring unit 16 measures the voltage applied between the pair of electrodes 12 a, 12 b and the current flowing between the pair of electrodes 12 a, 12 b, and calculates the impedance.

[0049] The switching unit 17 switches so that at least one of the pair of electrodes 12a, 12b is electrically connected to the power source 13 and the impedance measuring unit 16. When applying distortion to the oxide film 52 of the powder 50, the switching unit 17 switches so that the power source 13 is connected to the pair of electrodes 12a, 12b, and when measuring the impedance of the powder 50, the switching unit 17 switches so that the impedance measuring unit 16 is connected to the pair of electrodes 12a, 12b.

[0050] In the second embodiment, the control unit 15 controls the application of voltage in the powder manufacturing process using the measurement results of the impedance of the powder 50. In one example, the control unit 15 applies a voltage between the pair of electrodes 12a, 12b to stir the powder 50, and then switches the pair of electrodes 12a, 12b to connect the impedance measurement unit 16 using the switching unit 17. The control unit 15 selects a subsequent process based on the measured impedance. In this case, the impedance of the entire powder 50 after stirring is measured. That is, when the oxide film 52 of almost the entire powder 50 is distorted, the impedance of the entire powder 50 decreases. When the impedance of the entire powder 50 falls within a predetermined range, the powder manufacturing process ends. Here, the predetermined range is a range of impedance values ​​in which the oxide film 52 of the entire powder 50 is distorted and the powder 50 as a whole can be determined to be conductive. While it is desirable to distort the oxide film 52 of all the powder 50, it is nearly impossible to distort the oxide film 52 of all the powder 50. Therefore, when the overall impedance of powder 50 inside processing vessel 11 is within a range that allows it to be determined that powder 50 is conductive, it is determined that distortion has been imparted to oxide film 52 over almost the entire powder 50. In this manner, control unit 15 instructs switching unit 17 to switch the connection destination of at least one pair of electrodes 12a, 12b when applying a voltage between at least one pair of electrodes 12a, 12b and when measuring the impedance, and continues applying voltage and stirring powder 50 until the impedance value measured by impedance measurement unit 16 falls within a predetermined range, thereby making it possible to manage powder 50 produced in powder processing apparatus 10B to have a consistent quality.

[0051] The powder processing apparatus 10A of the first embodiment having the configuration shown in FIG. 6 may further include the impedance measuring unit 16 and the switching unit 17 described above.

[0052] Next, a powder manufacturing method using such powder processing apparatus 10B will be described. FIG. 9 is a flowchart showing an example of the processing procedure of the powder manufacturing method according to the second embodiment. Note that the same steps as those in FIG. 5 of the first embodiment are assigned the same step numbers, and their description will be omitted. In the second embodiment, when the termination condition for the powder manufacturing process is satisfied in step S14 (Yes in step S14), the control unit 15 instructs the switching unit 17 to switch so that at least one pair of electrodes 12a, 12b is connected to the impedance measuring unit 16 (step S21). Next, the impedance measuring unit 16 measures the impedance of the powder 50 between at least one pair of electrodes 12a, 12b (step S22). The process of step S22 corresponds to the impedance measuring process.

[0053] Thereafter, the control unit 15 determines whether the impedance measured by the impedance measuring unit 16 is within a predetermined range (step S23). If the measured impedance is not within the predetermined range (No in step S23), the process returns to step S12, and steps S12 to S23 are repeatedly executed until the measured impedance falls within the predetermined range. At this time, the termination condition for the second or subsequent executions of step S14 of the powder production process may be different from the termination condition for the first execution of the powder production process. For example, the termination condition for the second or subsequent executions of the powder production process is whether a predetermined period has elapsed or a predetermined number of voltage application processes have been performed since the determination using the measured impedance. This predetermined period may be shorter than the second period specified in the termination condition for the first execution of the powder production process. Furthermore, the predetermined number of times may be less than the number of times specified in the termination condition for the first execution of the powder production process. This is because the impedance of the entire powder 50 is considered to have decreased to some extent because the voltage application process and powder stirring process have already been performed for the second period or a predetermined number of times. If the measured impedance is within the predetermined range (Yes in step S23), the process proceeds to step S15.

[0054] In the above example, the impedance of the entire powder 50 after stirring is measured. However, the impedance between the pair of electrodes 12a and 12b after applying a voltage may also be measured. This allows confirmation of whether a current path is formed each time a voltage is applied. Specifically, after applying a voltage between the pair of electrodes 12a and 12b, the control unit 15 switches the switch unit 17 to connect the pair of electrodes 12a and 12b to the impedance measurement unit 16, and selects a subsequent process based on the measured impedance. If the impedance is smaller than a predetermined value, the control unit 15 performs stirring using the stirring mechanism 14. If the impedance is larger than a predetermined value, the control unit 15 switches the switch unit 17 to connect the pair of electrodes 12a and 12b to the power supply 13, and again applies a voltage between the pair of electrodes 12a and 12b. The control unit 15 then applies a voltage between the pair of electrodes 12a and 12b without stirring using the stirring mechanism 14 until the impedance becomes smaller than the predetermined value.

[0055] According to the second embodiment, powder processing apparatus 10B further includes an impedance measuring unit 16. If the impedance value of powder 50 after stirring measured by impedance measuring unit 16 is not within a predetermined range, control unit 15 further applies a voltage to powder 50 and stirs it, and if the measured impedance value is within the predetermined range, ends the powder production process. This ensures that the impedance of processed powder 50P produced by the powder production process has a constant value, providing the effect of managing processed powder 50P to have a constant quality, in addition to the effect of the first embodiment.

[0056] Embodiment 3 Next, a three-dimensional modeling apparatus including the powder processing apparatus 10 will be described. Fig. 10 is a diagram schematically illustrating an example of the configuration of a three-dimensional modeling apparatus according to embodiment 3. The three-dimensional modeling apparatus 200 according to embodiment 3 is an apparatus that irradiates treated powder 50P spread over a modeling area 202 with an electron beam 211a, melts and solidifies the treated powder 50P, and manufactures a three-dimensional model 201.

[0057] The three-dimensional modeling apparatus 200 according to the third embodiment includes a sealed chamber 210, an electron gun 211 that emits an electron beam 211a, a powder bed wall 212 that surrounds a modeling area 202 where modeling is performed by irradiating the electron beam 211a, a lifting stage 215 that is movable in the vertical direction (height direction) in the area surrounded by the powder bed wall 212, a powder supply means 213 that supplies powder 50 to the modeling area 202, and a powder processing apparatus 10 that performs a powder manufacturing process to reduce the impedance of the powder 50.

[0058] A vacuum pump (not shown), which is an exhaust device, is connected to the chamber 210. The interior of the chamber 210 is evacuated by the vacuum pump to create a vacuum or near-vacuum state. Inside the chamber 210, a powder bed wall 212, a powder supply means 213, an elevation stage 215, and a powder processing device 10 are provided.

[0059] The electron gun 211 is installed in an electron gun chamber 214 provided vertically above the chamber 210. The electron gun 211 has a mechanism for emitting electrons, a mechanism for converging the emitted electrons, and a mechanism for deflecting the electrons so that the electrons are irradiated at a specified position. The electron gun 211 adjusts the direction in which the electron beam 211a is deflected, thereby adjusting the irradiation position of the electron beam 211a.

[0060] The powder bed wall 212 has a cylindrical shape extending in the height direction. A lifting stage 215 that moves in the height direction is provided inside the cylindrical powder bed wall 212. The outer peripheral surface of the lifting stage 215 contacts the inner wall of the powder bed wall 212. The lifting stage 215 moves up and down while maintaining contact between the outer peripheral surface of the lifting stage 215 and the inner wall of the powder bed wall 212. The area surrounded by the cylindrical interior of the powder bed wall 212 and the lifting stage 215 is the shaping area 202 where shaping by irradiation with the electron beam 211a is performed. The upper end of the shaping area 202 coincides with the upper end of the powder bed wall 212. Note that a sealing member may be provided on the outer peripheral surface of the lifting stage 215. In this case, the lifting stage 215 moves up and down while maintaining contact between the sealing member and the inner wall of the powder bed wall 212. At the upper end of the powder bed wall 212, a platform portion 212a is formed that extends horizontally outside the manufacturing area 202.

[0061] A base plate 216 serving as a base for the three-dimensional object 201 is provided on the upper surface of the lifting stage 215. In one example, the base plate 216 is a rectangular flat plate. However, the shape of the base plate 216 is not limited to rectangular and may be circular, for example. In one example, the base plate 216 is placed on the upper surface of the lifting stage 215 by an operator when formation of the three-dimensional object 201 begins. After formation of the three-dimensional object 201 is completed, the base plate 216 is removed together with the three-dimensional object 201. Note that the base plate 216 may be supported in a parallel state by being placed on a plurality of supports erected on the upper surface of the lifting stage 215.

[0062] The powder supplying means 213 has a powder box 213a that stores the processed powder 50P and a recoater 213b that spreads the processed powder 50P evenly. When the processed powder 50P is discharged from the powder box 213a, the recoater 213b moves horizontally from above the platform 212a, through the modeling area 202, to the platform 212a beyond the modeling area 202. In this way, the recoater 213b spreads the processed powder 50P evenly in the modeling area 202. In this way, the recoater 213b moves horizontally from outside the modeling area 202 into the modeling area 202 to supply the processed powder 50P into the modeling area 202, and then spreads the processed powder 50P in the modeling area 202 to form a powder layer in the modeling area 202. The recoater 213b may have any configuration as long as it can spread the treated powder 50P evenly.

[0063] Examples of the powder 50 used in the third embodiment include titanium, titanium alloys such as Ti-6Al-4V, copper, copper alloys, and stainless steel. The powder 50 may be aluminum, aluminum alloys such as AlSi10Mg, titanium-aluminum alloys, tantalum (Ta) alloys, Inconel (registered trademark), Invar (registered trademark), Super Invar, cobalt-chromium (CoCr) alloys, Hastelloy (registered trademark), chromium-molybdenum (CrMo) steel, tungsten (W) alloys, or CoCrFeMnNi high-entropy alloys. The powder 50 used in the third embodiment may be metals or alloys other than those exemplified here.

[0064] The powder processing apparatus 10 is the powder processing apparatus 10 described in the first embodiment. Here, before storing the powder 50 in the powder box 213a, a process is performed to impart distortion to the oxide film 52 on the surface of the powder 50, thereby reducing the impedance of the entire powder 50 to a reference range. Thereafter, the powder processing apparatus 10 opens the lid 111 of the processing container 11 and supplies the processed powder 50P through the opening to the powder box 213a. Note that the detailed configuration of the powder processing apparatus 10 has been described in the first embodiment, and therefore will not be described here. Furthermore, although FIG. 10 illustrates the powder processing apparatus 10 of the first embodiment, the powder processing apparatus 10 may be the powder processing apparatus 10A of the first embodiment or the powder processing apparatus 10B of the second embodiment.

[0065] The powder production process in the powder processing apparatus 10 is performed before the modeling process in the three-dimensional modeling apparatus 200. As described above, the powder processing apparatus 10 applies a voltage between a pair of electrodes 12a, 12b to distort the oxide film 52 of the powder 50. If the powder production process is performed during the modeling of the three-dimensional object 201, the voltage applied by the powder processing apparatus 10 may affect the electron beam 211a from the electron gun 211, which may result in the failure to model the desired three-dimensional object 201. For this reason, the powder production process is performed before the modeling of the three-dimensional object 201. Note that the powder processing apparatus 10 is preferably disposed above the powder box 213a. This allows the processed powder 50P to be directly supplied to the powder box 213a through the opening of the processing container 11 by opening the lid 111 of the processing container 11 after the powder production process.

[0066] The three-dimensional modeling apparatus 200 also has a control device 217 that controls the entire three-dimensional modeling apparatus 200. The control device 217 controls the electron gun 211 by outputting a control signal to the electron gun 211. The electron gun 211 controls the emission and stop of emission of the electron beam 211a and the energy of the electron beam 211a in accordance with the control signal. The electron gun 211 adjusts the height position at which the electron beam 211a is converged in accordance with the control signal.

[0067] Furthermore, the electron gun 211 adjusts the irradiation position of the electron beam 211a in accordance with the control signal. In one example, CAD (Computer-Aided Design) data, which is design data for the three-dimensional object 201, is input to the control device 217. The control device 217 generates two-dimensional slice data based on the CAD data. The slice data represents the cross-sectional shape of the three-dimensional object 201 for each layer stacked in the height direction. The control device 217 determines the irradiation position of the electron beam 211a based on the slice data, and outputs a control signal including an instruction for the irradiation position.

[0068] Furthermore, the control device 217 controls the operation of the powder processing device 10 by outputting a control signal to the powder processing device 10. Before performing the modeling process in the three-dimensional modeling device 200, the control device 217 gives the powder processing device 10 an instruction for the powder production process. As a result, the powder processing device 10 performs the powder production process described in the first and second embodiments and supplies the processed powder 50P to the powder box 213a. When the powder production process is completed, the control unit 15 of the powder processing device 10 turns off the power supply 13 and sends a signal indicating the completion of the powder production process to the control device 217. When the control device 217 receives the signal indicating the completion of the powder production process, it determines that it is ready to perform the three-dimensional modeling process and performs the three-dimensional modeling process.

[0069] Furthermore, the control device 217 controls the recoater 213b by outputting a control signal to the recoater 213b. The recoater 213b moves horizontally in accordance with the control signal. The control device 217 controls the lift stage 215 by outputting a control signal to the lift stage 215. The lift stage 215 moves vertically in accordance with the control signal. The control device 217 adjusts the height position of the base plate 216 by controlling the lift stage 215.

[0070] Next, a description will be given of a method for manufacturing a three-dimensional object 201 using the above-described three-dimensional printing apparatus 200. The method for manufacturing the three-dimensional object 201 involves spreading powder 50 in a printing area 202 inside a chamber 210, irradiating the powder 50 with an electron beam 211a, and melting and solidifying the powder 50 to form a three-dimensional object.

[0071] 11 is a flowchart showing an example of a processing procedure of the method for manufacturing a three-dimensional structure according to the third embodiment. First, a powder manufacturing process is performed on the powder 50 used in manufacturing the three-dimensional structure 201 (step S31). The control device 217 outputs a control signal to the powder processing apparatus 10, thereby executing the powder manufacturing method shown in FIG. 5 of the first embodiment or FIG. 9 of the second embodiment. At this time, the inside of the chamber 210 in which the powder processing apparatus 10 is placed is evacuated to a predetermined vacuum level by a vacuum pump. This powder manufacturing process produces the powder 50 in which distortion has been imparted to the oxide film 52.

[0072] Next, the powder processing apparatus 10 opens the lid portion 111 and supplies the processed powder 50P from the opening of the processing container 11 to the powder box 213a of the powder supply means 213 (step S32). The process of step S32 corresponds to a powder supply process.

[0073] Next, the processed powder 50P supplied from the powder supply means 213 is spread evenly in the modeling area 202 to form a powder layer (step S33). Specifically, the processed powder 50P is supplied from the powder box 213a onto the platform 212a. Thereafter, the recoater 213b is moved horizontally in an area including the modeling area 202 to spread the processed powder 50P evenly on the base plate 216, thereby forming a powder layer in the recess formed by the lift stage 215 and the powder bed wall 212. The control device 217 outputs a control signal to the recoater 213b, thereby controlling the operation of the recoater 213b. The process of step S33 corresponds to a powder layer forming process.

[0074] Thereafter, the fabrication area 202 is irradiated with a preheating electron beam 211a to preheat the powder layer (step S34). The irradiation of the preheating electron beam 211a in step S34 heats the pre-processed powder 50P before fabricating the three-dimensional object 201. The control device 217 outputs a control signal to the electron gun 211, thereby controlling the emission and deflection of the electron beam 211a from the electron gun 211, and as a result, the irradiation position of the electron beam 211a is controlled. The processed powder 50P on the base plate 216 is irradiated with the electron beam 211a, so that the processed powder 50P is heated. For example, in the preheating process, the processed powder 50P is heated to a temperature at which the processed powder 50P does not melt. Note that the irradiation of the preheating electron beam 211a may be performed as needed. The process of step S34 corresponds to the preheating process.

[0075] Next, the control device 217 irradiates the powder layer with the electron beam 211a for melting based on the generated slice data, thereby forming one modeling layer (step S35). In one example, the control device 217 determines an irradiation area of ​​the processed powder 50P to be irradiated with the electron beam 211a based on the slice data. Then, the control device 217 causes the electron gun 211 to irradiate the electron beam 211a according to the irradiation area. The processed powder 50P in the irradiation area irradiated with the electron beam 211a melts and solidifies, and becomes a part of the modeling layer that constitutes the three-dimensional model 201, unlike the processed powder 50P not irradiated with the electron beam 211a. The process of step S35 corresponds to the electron beam irradiation process.

[0076] In the irradiation of the treated powder 50P with the preheating electron beam 211a in step S34 and the melting electron beam 211a in step S35, the powder layer is made of the treated powder 50P, i.e., the treated powder 50P has a reduced impedance. Therefore, electrons from the irradiated electron beam 211a are not trapped in the treated powder 50P, preventing the treated powder 50P from becoming charged. As a result, the occurrence of smoke is suppressed during irradiation with the electron beam 211a.

[0077] Thereafter, the control device 217 determines whether or not the formation of the three-dimensional object 201 is completed (step S36). In one example, if the three-dimensional object 201 has not reached the desired height, it determines that the formation is not completed. Step S36 corresponds to the determination step.

[0078] If the formation of the three-dimensional object 201 is not complete (No in step S36), the control device 217 lowers the lifting stage 215 by the height of one layer (step S37), and the process returns to step S33. The process in step S37 corresponds to a stage lowering process. Then, the procedures from step S33 to step S37 are repeated until the formation of all layers of the three-dimensional object 201 is complete.

[0079] When the formation of all layers is completed, that is, when the formation of the three-dimensional object 201 is completed (Yes in step S36), the control device 217 determines that the manufacture of the three-dimensional object 201 is completed, and the process ends.

[0080] Next, a description will be given of the hardware configuration of the control device 217. The functions of the control device 217 are realized by executing a control program, which is a program for controlling the 3D printing device 200, using hardware.

[0081] 12 is a block diagram showing an example of the hardware configuration of a control device included in the layered manufacturing apparatus according to embodiment 3. The control device 217 has a CPU 301 that executes various processes, a RAM 302 that includes a data storage area, a ROM 303 that is a non-volatile memory, a storage device 304, and an input / output interface 305 for inputting information to the control device 217 and outputting information from the control device 217. The components shown in FIG. 12 are connected to each other via a bus 306.

[0082] The CPU 301 executes a program stored in the ROM 303 or the storage device 304. The overall control of the three-dimensional modeling apparatus 200 by the control device 217 is realized using the CPU 301.

[0083] The storage device 304 is a hard disk drive (HDD) or a solid state drive (SSD). The storage device 304 stores a control program and various data. The ROM 303 stores a boot loader such as a basic input / output system (BIOS) or a unified extensible firmware interface (UEFI), which is a basic control program for the computer or controller that is the control device 217, and software or a program that controls the hardware. The control program may be stored in the ROM 303.

[0084] The programs stored in the ROM 303 and the storage device 304 are loaded into the RAM 302. The CPU 301 loads the control programs into the RAM 302 and executes various processes. The input / output interface 305 is an interface for connecting the control device 217 to devices external to the control device 217. Machining programs, CAD data, etc. are input to the input / output interface 305. The input / output interface 305 also outputs various commands. The control device 217 may have input devices such as a keyboard and a pointing device, and an output device such as a display.

[0085] The control program may be stored in a computer-readable storage medium. The control device 217 may store the control program stored in the storage medium in the storage device 304. The storage medium may be a portable storage medium such as a flexible disk, or a flash memory such as a semiconductor memory. The control program may be installed in the computer or controller that becomes the control device 217 from another computer or server device via a communication network.

[0086] The functions of the control device 217 may be realized by a processing circuit, which is dedicated hardware for controlling the 3D printing device 200. The processing circuit is a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. Some of the functions of the control device 217 may be realized by dedicated hardware, and other parts may be realized by software or firmware.

[0087] In the third embodiment, a three-dimensional printing apparatus 200 includes, inside a chamber 210, the powder processing apparatuses 10, 10A, and 10B described in the first and second embodiments. Before the three-dimensional printing apparatus 200 produces a three-dimensional object 201, a powder production process is performed to distort the oxide film 52 of the powder 50. After the powder production process is completed, the lid 111 of the processing container 11 is opened, and the processed powder 50P is supplied to the powder box 213a through the opening. In the three-dimensional printing apparatus 200, the processed powder 50P with reduced impedance is spread all over the surface. Even when the processed powder 50P is irradiated with an electron beam 211a, the processed powder 50P is not charged because it has conductivity, and thus the occurrence of the smoke phenomenon can be suppressed.

[0088] In the technology described in Patent Document 1, the ball mill or jet mill is disposed outside the three-dimensional modeling apparatus 200. After the grinding process in the ball mill or jet mill is completed, the container must be removed from the respective device and transferred to the powder box 213a in the chamber 210 of the three-dimensional modeling apparatus 200. In particular, in the case of the ball mill, the container containing the ground powder 50 must be transferred. Thus, the technology described in Patent Document 1 has a problem in that it takes time and effort to supply the ground powder 50 to the powder box 213a of the three-dimensional modeling apparatus 200. On the other hand, in the three-dimensional modeling apparatus 200 according to the third embodiment, the powder processing devices 10, 10A, and 10B are disposed above the powder box 213a inside the chamber 210. Therefore, after the powder production process in the powder processing devices 10, 10A, and 10B is completed, the processed powder 50P can be supplied to the powder box 213a simply by opening the lid 111 and adjusting the opening so that it faces the powder box 213a. Compared to the case of Patent Document 1, it is possible to supply the processed powder 50P to the powder box 213a with fewer steps.

[0089] Furthermore, in the technology described in Patent Document 1, the processed powder 50P is exposed to the atmosphere and is likely to be affected by oxidation to some extent. However, in the three-dimensional modeling apparatus 200 according to the third embodiment, the powder processing apparatuses 10, 10A, and 10B are arranged in the evacuated chamber 210, and therefore the processed powder 50P after the powder manufacturing process is not exposed to the atmosphere until it is supplied to the powder box 213a.

[0090] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention.

[0091] Various aspects of the present disclosure are summarized below as appendices.

[0092] [Appendix 1] At least one pair of electrodes; a processing vessel surrounding the space between the at least one pair of electrodes and containing metal powder; a stirring mechanism that stirs the metal powder inside the processing vessel; a power source that applies a voltage between the at least one pair of electrodes; a control unit that controls the operation of the stirring mechanism and the power source; Equipped with 10. A powder processing apparatus, wherein at least the inner circumferential surface of the processing container is made of an insulating material. [Appendix 2] The powder processing apparatus according to claim 1, wherein the control unit controls the stirring mechanism and the power supply so that the application of the voltage and the stirring of the metal powder are alternately performed. [Appendix 3] 2. The powder processing apparatus according to claim 1, wherein the control unit controls the stirring mechanism and the power supply so that the application of the voltage and the stirring of the metal powder are performed simultaneously. [Appendix 4] an impedance measuring unit that measures the impedance between the at least one pair of electrodes; a switching unit that switches between the power supply and the impedance measuring unit so that either one of the power supply and the impedance measuring unit is electrically connected to the at least one pair of electrodes; Furthermore, The powder processing apparatus according to any one of appendixes 1 to 3, characterized in that the control unit instructs the switching unit to switch the connection destination of the at least pair of electrodes when the voltage is applied between the at least pair of electrodes and when the impedance is measured, and continues applying the voltage and stirring the metal powder until the impedance value measured by the impedance measuring unit falls within a predetermined range. [Appendix 5] The powder processing apparatus described in Appendix 2 or 3, characterized in that the control unit continues applying the voltage and stirring the metal powder until a predetermined period of time has elapsed or a predetermined number of times has been reached. [Appendix 6] The powder processing apparatus described in any one of appendices 1 to 5, characterized in that the voltage applied to each metal powder between the pair of electrodes is a voltage between a first threshold value, which is the lowest value of voltage applied to each metal powder that can distort the oxide film on the surface of the metal powder, and a second threshold value, which is the value of voltage applied to each metal powder when the oxide film on the surface of the metal powder between adjacent metal powders is destroyed. [Appendix 7] 7. The powder processing device according to claim 1, wherein the stirring mechanism comprises a rotating shaft fixed to the center of the bottom surface of the processing container and a drive unit that rotates the rotating shaft. [Appendix 8] 7. The powder processing apparatus according to claim 1, wherein the stirring mechanism comprises a propeller provided inside the processing vessel, a rotating shaft that rotates the propeller, and a drive unit that rotates the rotating shaft. [Appendix 9] 1. A three-dimensional modeling apparatus that irradiates an electron beam onto metal powder spread in a modeling area to melt and solidify the metal powder to form a three-dimensional model, an electron gun that emits the electron beam; a powder bed wall surrounding a building area where building is performed by irradiating the electron beam; a powder supplying means for supplying the metal powder to the building area; A powder processing device according to any one of appendices 1 to 8; A three-dimensional modeling apparatus comprising: [Appendix 10] the powder processing device is disposed above the powder supply means; 10. The three-dimensional printing apparatus according to claim 9, wherein the processing container of the powder processing apparatus has an opening through which the metal powder can be put in and taken out, and a lid that covers the opening and can be opened and closed. [Appendix 11] a powder introducing step of introducing metal powder into a processing vessel that surrounds a space between at least a pair of electrodes and has at least an inner circumferential surface made of an insulating material; a voltage application step of applying a voltage between the at least one pair of electrodes; a stirring step of stirring the metal powder inside the processing vessel; A method for producing a powder, comprising: [Appendix 12] 12. The powder manufacturing method according to claim 11, wherein the voltage application step and the stirring step are alternately performed. [Appendix 13] 12. The powder manufacturing method according to claim 11, wherein the voltage application step and the stirring step are carried out simultaneously. [Appendix 14] further comprising an impedance measuring step of measuring an impedance between the at least one pair of electrodes; 14. The powder manufacturing method according to claim 11, wherein the voltage application step and the stirring step are performed until the impedance value measured in the impedance measurement step falls within a predetermined range. [Appendix 15] A method for manufacturing a three-dimensional object, comprising: spreading metal powder in a manufacturing area inside a chamber; irradiating the metal powder with an electron beam; and melting and solidifying the metal powder to form a three-dimensional object, a powder introducing step of introducing the metal powder into a processing vessel disposed inside the chamber, the processing vessel having at least an inner circumferential surface made of an insulating material; a voltage applying step of applying a voltage between at least a pair of electrodes disposed inside the processing vessel; a stirring step of stirring the metal powder inside the processing vessel; a powder supplying step of supplying the metal powder from an opening of the processing vessel to a powder supplying means disposed inside the chamber; a powder layer forming step of forming a powder layer by evenly spreading the metal powder supplied from the powder supply means in the building area; an electron beam irradiation step of irradiating the powder layer with the electron beam; A method for manufacturing a three-dimensional object, comprising: [Explanation of symbols]

[0093] 10, 10A, 10B powder processing device, 11 processing container, 12 electrode pair, 12a, 12b electrodes, 13 power supply, 14 stirring mechanism, 15 control unit, 16 impedance measurement unit, 17 switching unit, 50, 50a, 50b powder, 50P processed powder, 51 center, 52 oxide film, 111 lid, 145 propeller, 146 rotating shaft, 147 drive unit, 200 three-dimensional printing device, 201 three-dimensional object, 202 printing area, 210 chamber, 211 electron gun, 211a electron beam, 212 powder bed wall, 212a base, 213 powder supply means, 213a powder box, 213b recoater, 214 electron gun chamber, 215 lift stage, 216 base plate, 217 control device.

Claims

1. At least one pair of electrodes; a processing vessel surrounding the space between the at least one pair of electrodes and containing metal powder; a stirring mechanism that stirs the metal powder inside the processing vessel; a power source that applies a voltage between the at least one pair of electrodes; a control unit that controls the operation of the stirring mechanism and the power source; Equipped with 10. A powder processing apparatus, wherein at least the inner circumferential surface of the processing container is made of an insulating material.

2. The powder processing apparatus according to claim 1 , wherein the control unit controls the stirring mechanism and the power source so that the application of the voltage and the stirring of the metal powder are alternately performed.

3. The powder processing apparatus according to claim 1 , wherein the control unit controls the stirring mechanism and the power source so that the application of the voltage and the stirring of the metal powder are carried out simultaneously.

4. an impedance measuring unit that measures the impedance between the at least one pair of electrodes; a switching unit that switches between the power supply and the impedance measuring unit so that either one of the power supply and the impedance measuring unit is electrically connected to the at least one pair of electrodes; Furthermore, 2. The powder processing apparatus according to claim 1, wherein the control unit instructs the switching unit to switch the connection destination of the at least pair of electrodes when the voltage is applied between the at least pair of electrodes and when the impedance is measured, and continues applying the voltage and stirring the metal powder until the impedance value measured by the impedance measuring unit falls within a predetermined range.

5. The powder processing apparatus according to claim 2 , wherein the control unit continues to apply the voltage and agitate the metal powder until a predetermined period of time has elapsed or until a predetermined number of times has been reached.

6. The powder processing apparatus according to claim 1, characterized in that the voltage is determined so that a voltage between a first threshold value, which is the minimum value of the voltage applied to each metal powder that can distort the oxide film on the surface of the metal powder, and a second threshold value, which is the value of the voltage applied to each metal powder when the oxide film on the surface of the metal powder between adjacent metal powders is destroyed, is applied to each metal powder between the pair of electrodes.

7. 2. The powder processing apparatus according to claim 1, wherein the stirring mechanism comprises a rotation shaft fixed to the center of the bottom surface of the processing vessel, and a drive unit for rotating the rotation shaft.

8. 2. The powder processing apparatus according to claim 1, wherein the stirring mechanism comprises a propeller provided inside the processing vessel, a rotation shaft that rotates the propeller, and a drive unit that rotates the rotation shaft.

9. 1. A three-dimensional modeling apparatus that irradiates an electron beam onto metal powder spread in a modeling area to melt and solidify the metal powder to form a three-dimensional model, an electron gun that emits the electron beam; a powder bed wall surrounding a building area where building is performed by irradiating the electron beam; a powder supplying means for supplying the metal powder to the building area; A powder processing device according to any one of claims 1 to 8; A three-dimensional modeling apparatus comprising:

10. the powder processing device is disposed above the powder supply means; 10. The three-dimensional modeling apparatus according to claim 9, wherein the processing container of the powder processing apparatus has an opening through which the metal powder can be put in and taken out, and a lid that covers the opening and can be opened and closed.

11. a powder introducing step of introducing metal powder into a processing vessel that surrounds a space between at least a pair of electrodes and has at least an inner circumferential surface made of an insulating material; a voltage application step of applying a voltage between the at least one pair of electrodes; a stirring step of stirring the metal powder inside the processing vessel; A method for producing a powder, comprising:

12. The powder manufacturing method according to claim 11, wherein the voltage application step and the stirring step are performed alternately.

13. The powder manufacturing method according to claim 11, wherein the voltage application step and the stirring step are carried out simultaneously.

14. further comprising an impedance measuring step of measuring an impedance between the at least one pair of electrodes; 14. The powder manufacturing method according to claim 11, wherein the voltage application step and the stirring step are performed until the impedance value measured in the impedance measurement step falls within a predetermined range.

15. A method for manufacturing a three-dimensional object, comprising: spreading metal powder in a manufacturing area inside a chamber; irradiating the metal powder with an electron beam; and melting and solidifying the metal powder to form a three-dimensional object, a powder introducing step of introducing the metal powder into a processing vessel disposed inside the chamber, the processing vessel having at least an inner circumferential surface made of an insulating material; a voltage applying step of applying a voltage between at least a pair of electrodes disposed inside the processing vessel; a stirring step of stirring the metal powder inside the processing vessel; a powder supplying step of supplying the metal powder from an opening of the processing vessel to a powder supplying means disposed inside the chamber; a powder layer forming step of forming a powder layer by evenly spreading the metal powder supplied from the powder supply means in the building area; an electron beam irradiation step of irradiating the powder layer with the electron beam; A method for manufacturing a three-dimensional object, comprising:

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