Method for manufacturing metal additive manufacturing body

Abstract

This method for manufacturing a metal laminate formed body repeats a forming step. The method comprises: a forming step in which, while a shielding gas blowing unit (15) blows a shielding gas (24), a heating unit (13), which moves relative to a stage (17) where a forming object is placed, produces a heat source (23) to heat a metal raw material (5) supplied by a supply unit (14) on a first path on the forming object, and a bead (20) of the metal raw material (5) melted by the heating unit (13) is deposited on the forming object; and a cooling step, which comes before a subsequent molding step, in which heating by the heating unit (13) is stopped, and a cooling medium (25) is blown from a cooling unit (11), which moves relative to the stage (17), for cooling on a second path on the forming object which is oriented in the same or opposite direction of the first path.

Description

[Technical Field]

[0001] The present disclosure relates to a method and an apparatus for manufacturing a metal additive manufacturing object, which is manufactured by stacking metal. [Background technology]

[0002] Conventionally, a known technology for creating three-dimensional objects is a metal additive manufacturing (AM) manufacturing device that uses a technology called additive manufacturing (AM), which involves melting and solidifying metal raw materials and layering them on a substrate. The raw material melting conditions are determined by the amount of heat input required to melt the raw material, the temperature of the base, and the amount of heat removed from the base. As the molding process continues, the amount of heat input exceeds the amount of heat removed, causing heat to accumulate in the base metal. Heat accumulation can change the state of the base layer, altering the optimal melting conditions. Therefore, cooling mechanisms are being investigated to cool the molded object.

[0003] Patent Document 1 discloses a metal additive manufacturing device that includes an arc torch that generates an arc while flowing a shielding gas to melt and solidify metal to form layers, and a cooling unit. The cooling unit in Patent Document 1 is configured to be located behind the arc torch. This configuration allows the cooling unit to spray a refrigerant, which is a cooling medium, from behind the arc torch to cool the object during the manufacturing process in which the metal is melted and layered. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] WO2021 / 117468 publication Summary of the Invention [Problem to be solved by the invention]

[0005] In the metal additive manufacturing device disclosed in Patent Document 1, a cooling unit sprays a cooling medium from behind the arc torch during manufacturing. Typically, an inert gas called a shielding gas is sprayed at the manufacturing point where the metal is melted to prevent the molded object from oxidizing. In the metal additive manufacturing device disclosed in Patent Document 1, a shielding gas flows from a shield nozzle attached to the arc torch, and there is a risk of interference between the shielding gas and the cooling medium during manufacturing. If the cooling medium interferes with the shielding gas during manufacturing, proper shielding cannot be achieved at the manufacturing point, which may cause oxidation of the molten metal during manufacturing. Furthermore, gases such as the cooling medium and the atmosphere may be entrained during manufacturing, which may result in gas pores inside the molded object.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to suppress interference between the shielding gas and the cooling medium during molding. [Means for solving the problem]

[0007] The method for manufacturing a metal additive manufacturing object according to the present disclosure involves repeating a manufacturing process, and includes a manufacturing process and a cooling process. In the manufacturing process, a shielding gas is sprayed from a shielding gas spraying unit, while a heating unit, which moves relative to a stage on which the object is placed, emits a heat source to heat a metal raw material supplied by a supply unit, and the heating unit deposits a bead of molten metal raw material on the object, thereby manufacturing the object layer by layer. In the cooling process, before the next manufacturing process, a cooling unit, separate from the shielding gas spraying unit, sprays a cooling medium at a flow rate greater than the flow rate of the shielding gas while moving relative to the stage, thereby cooling the object manufactured in the manufacturing process. The metal additive manufacturing object is formed by repeatedly depositing, on the object, each layer of the bead manufactured in the manufacturing process. In the modeling process, a heating unit heats a metal raw material along a first path on the model, which is a path from the modeling start position to the modeling end position, thereby modeling a single-layer model that forms a metal additive manufacturing body, and the cooling unit stops spraying a cooling medium while the heating unit is heating. In the cooling process, a cooling unit sprays a cooling medium along a second path on the model, which is a path from the cooling start position to the cooling end position, thereby cooling the single-layer model modeled in the modeling process, and the second path is in the same or opposite direction to the first path, and the heating unit stops heating while the cooling unit is cooling. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to suppress interference between the shielding gas and the cooling medium during molding, thereby obtaining a higher quality molded object. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view showing a metal additive manufacturing apparatus according to a first embodiment. FIG. [Figure 2] 1 is a schematic cross-sectional view showing the entirety of a metal additive manufacturing apparatus according to a first embodiment. [Figure 3] 1 is a block diagram showing a hardware configuration of a control device according to a first embodiment. [Figure 4]1 is a schematic diagram showing a shaped object manufactured by the metal additive manufacturing apparatus according to Example 1 of Embodiment 1. FIG. [Figure 5] FIG. 2 is a schematic diagram showing the trajectory of a modeling path and the trajectory of a cooling path in a model manufactured by the metal additive manufacturing apparatus according to Example 1 of Embodiment 1. [Figure 6] 4 is a flowchart showing the operation of the manufacturing device and manufacturing method for a metal additive manufacturing object according to Example 1 of Embodiment 1. [Figure 7] FIG. 10 is a schematic diagram showing the trajectory of a modeling path and the trajectory of a cooling path in a model manufactured by the metal additive manufacturing apparatus according to Comparative Example 1 of the first embodiment. [Figure 8] FIG. 10 is a schematic diagram showing a shaped object manufactured by the metal additive manufacturing apparatus according to Example 2 of Embodiment 1. [Figure 9] FIG. 10 is a schematic diagram showing the trajectory of a modeling path and the trajectory of a cooling path in a model manufactured by the metal additive manufacturing apparatus according to Example 2 of Embodiment 1. [Figure 10] FIG. 10 is a schematic cross-sectional view showing a manufacturing apparatus for a metal additive manufacturing object according to Example 3 of Embodiment 2. [Figure 11] 10 is a flowchart showing the operation of a manufacturing device and a manufacturing method for a metal additive manufacturing object according to Example 3 of Embodiment 2. [Figure 12] FIG. 10 is a schematic diagram showing the trajectory of a modeling path and the trajectory of a cooling path in a model manufactured by the metal additive manufacturing apparatus according to Example 3 of Embodiment 2. [Figure 13] 10 is a flowchart showing the operation of a manufacturing device and a manufacturing method for a metal additive manufacturing object according to Example 4 of Embodiment 2. [Figure 14] FIG. 10 is a schematic cross-sectional view showing a manufacturing apparatus for a metal additive manufacturing object according to Example 5 of Embodiment 2. [Figure 15] 10 is a flowchart showing the operation of a manufacturing device and a manufacturing method for a metal additive manufacturing object according to Example 5 of Embodiment 2. [Figure 16] FIG. 10 is a schematic cross-sectional view showing a manufacturing apparatus for a metal additive manufacturing object according to Example 6 of Embodiment 3. [Figure 17]FIG. 11 is a schematic cross-sectional view showing a modified example of the metal additive manufacturing apparatus according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a method and an apparatus for manufacturing a metal additive manufacturing object according to an embodiment of the present disclosure will be described in detail with reference to the drawings. However, the present disclosure is not limited to the embodiment.

[0011] In the present disclosure, the method and apparatus for manufacturing a metal additive manufacturing object manufacture a three-dimensional object by depositing and layering metal raw materials melted by a heat source onto an object.

[0012] Metal additive manufacturing equipment forms objects from metal raw materials by depositing beads on a base material. A bead is a molten metal raw material or an object formed by solidifying molten metal raw material. A molded object is a bead or a deposit of beads. A molded object is also an object on which a bead is placed, and includes the base material. A molded object is also called a workpiece. By depositing beads to form the desired shape, a desired 3D additive object can be obtained.

[0013] Embodiment 1 The first embodiment relates to a method for manufacturing a metal additive manufacturing object and a manufacturing apparatus 100. First, a description will be given of the manufacturing apparatus 100 used in the method for manufacturing a metal additive manufacturing object.

[0014] The configuration of a metal additive manufacturing apparatus 100 according to embodiment 1 will be described. Fig. 1 is a schematic cross-sectional view showing the metal additive manufacturing apparatus 100 according to embodiment 1. Fig. 2 is a schematic cross-sectional view showing the entire metal additive manufacturing apparatus 100 according to embodiment 1.

[0015] As shown in Figure 1, the metal additive manufacturing apparatus 100 of embodiment 1 includes a wire nozzle 14 that supplies wire 5, which is a metal raw material; a beam nozzle 13 that emits a laser beam 23, which is a heat source, to heat the wire 5; a stage 17 that moves relative to the beam nozzle 13 and on which a model is placed on which the beam nozzle 13 deposits a bead 20 formed by melting the wire 5; a shielding gas nozzle 15 that sprays shielding gas 24 toward a processing point 22; a cooling nozzle 11 that moves relative to the stage 17 and sprays a cooling medium 25 toward the processing point 22; and a control device 1 that controls the beam nozzle 13 to move relative to the stage 17 while heating the wire 5 along a first path on the model, and then stopping the heating of the beam nozzle 13 and moving the cooling nozzle 11 relative to the stage 17 while spraying a cooling medium 25 along a second path on the model that is the same as or opposite to the first path to cool the model. The wire nozzle 14 is a supply unit, the beam nozzle 13 is a heating unit, the shielding gas nozzle 15 is a shielding gas spraying unit, the cooling nozzle 11 is a cooling unit, and the control device 1 is a control unit. The object is a base material 19 or a bead 20 formed on the base material 19 including the base material 19.

[0016] The processing point 22 is the position on the object where the beam nozzle 13 emits the laser beam 23 to heat the wire 5. The wire 5 melted by the beam nozzle 13 is deposited on the object to form a desired shape, so the processing point 22 is also the position where the object is formed.

[0017] Here, the shielding gas nozzle 15 sprays the shielding gas 24 toward the processing point 22, and the cooling nozzle 11 sprays the cooling medium 25 toward the processing point 22. However, generally, when gas is emitted from the nozzle, at least a portion of it diffuses, so the gas comes into contact with areas other than the processing point 22. Therefore, when gas such as the shielding gas 24 or the cooling medium 25 is sprayed toward the processing point 22, it means that the gas is also sprayed in the surrounding area of ​​the processing point 22. The surrounding area of ​​the processing point 22 varies depending on the properties of the gas being sprayed and the performance of the nozzles such as the shielding gas nozzle 15 and the cooling nozzle 11.

[0018] 1 , the metal additive manufacturing apparatus 100 according to the first embodiment includes a processing head 12. In the first embodiment, a wire nozzle 14, a beam nozzle 13, a shielding gas nozzle 15, and a cooling nozzle 11 are fixed to the processing head 12, and the processing head 12 moves relative to a stage 17 on which a model is placed. In other words, the movement of the processing head 12 relative to the stage 17 allows the wire nozzle 14, the beam nozzle 13, the shielding gas nozzle 15, and the cooling nozzle 11 to move relative to the stage 17.

[0019] In the manufacturing method disclosed below, the manufacturing process is separated into a shaping process and a cooling process. In the shaping process, the beam nozzle 13 emits a laser beam 23, but in the cooling process, the cooling nozzle 11 sprays a cooling medium 25 and the beam nozzle 13 does not emit the laser beam 23. Here, the wire nozzle 14, the beam nozzle 13, the shield gas nozzle 15, and the cooling nozzle 11 are fixed to the processing head 12, thereby fixing the relative positional relationship between the nozzles. The cooling nozzle 11 is fixed to the processing head 12 so that the processing point 22 in the shaping process and the position where the cooling nozzle 11 sprays the cooling medium 25 in the cooling process coincide with each other. As a result, even if the beam nozzle 13 does not emit the laser beam 23 in the cooling process, the cooling nozzle 11 can spray the cooling medium 25 toward the processing point 22 in the shaping process.

[0020] The control device 1 controls the operation of the metal additive manufacturing apparatus 100, and the control will be described in detail later.

[0021] The wire nozzle 14, which is a supply unit, supplies the wire 5, which is a metal raw material. The wire nozzle 14 advances the wire 5 toward the position where the beam nozzle 13 emits the laser beam 23, i.e., toward the processing point 22. As shown in FIG. 1, the wire nozzle 14 is provided at a position different from the beam nozzle 13, and the wire nozzle 14 advances the wire 5 in a direction oblique to the direction where the beam nozzle 13 emits the laser beam 23. Note that the relative positions and directions of the wire nozzle 14 and the beam nozzle 13 may be changed depending on the shape of the desired object.

[0022] The wire spool 6, the rotary motor 4, and the wire nozzle 14 constitute a wire supply mechanism that supplies the wire 5. As shown in FIG. 2, the wire 5 is wound around the wire spool 6, which is a supply source of raw metal material. The wire spool 6 is attached to the rotary motor 4, which is a servo motor. When the rotary motor 4 is driven, the wire spool 6 rotates, and the wire 5 is unwound from the wire spool 6. The wire 5 unwound from the wire spool 6 passes through the wire nozzle 14 and is supplied to the processing point 22. Furthermore, when the rotary motor 4 is rotated in the direction opposite to the direction in which the wire 5 is unwound from the wire spool 6, the wire 5 supplied to the processing point 22 can be pulled out. In this case, the unwound wire 5 is wound up by rotating the rotary motor 4 in the reverse direction and stored in the wire spool 6. Note that other methods of supplying the wire 5 may also be used.

[0023] The wire 5 is an example of a metal raw material for producing a metal additive manufacturing object, but the metal raw material is not limited to a linear one such as the wire 5, and may be, for example, a powder. Furthermore, the material of the metal raw material such as the wire 5 may be, for example, a Ni-based alloy, an Fe-based alloy, an Al-based alloy, a Ti-based alloy, or other metals.

[0024] The beam nozzle 13, which is a heating unit, emits a laser beam 23, which is a heat source, toward a position where an object is to be formed, thereby heating and melting the wire 5 supplied from the wire nozzle 14. The laser oscillator 2, the fiber cable 3, and the beam nozzle 13 constitute a heating mechanism that emits the laser beam 23. As shown in FIG. 2, the beam nozzle 13 is connected to the laser oscillator 2, which emits the laser beam 23, by the fiber cable 3. The laser beam 23 is emitted from the laser oscillator 2, passes through the fiber cable 3, and is emitted through the beam nozzle 13 fixed to the processing head 12. The heat source is not limited to the laser beam 23, and an arc, for example, may be used.

[0025] The shielding gas nozzle 15, which is a shielding gas spraying unit, sprays a shielding gas 24 toward the molded object to prevent oxidation of the molded object. As shown in FIG. 1, the shielding gas nozzle 15 sprays the shielding gas 24 toward the machining point 22. The shielding gas supply device 7, the shielding gas piping 8, and the shielding gas nozzle 15 constitute a shielding gas spraying mechanism that sprays the shielding gas 24. As shown in FIG. 2, the shielding gas nozzle 15 is connected to the shielding gas supply device 7, which supplies the shielding gas 24 via the shielding gas piping 8. The shielding gas 24 is transmitted from the shielding gas supply device 7 via the shielding gas piping 8 to the shielding gas nozzle 15 fixed to the machining head 12.

[0026] 1, the shielding gas nozzle 15 is provided on the outer periphery of the beam nozzle 13 with the central axis of the beam nozzle 13 as its central axis. In other words, the shielding gas nozzle 15 is coaxial with the beam nozzle 13. The shielding gas nozzle 15 sprays the shielding gas 24 in the same direction as the emission direction of the laser beam 23 emitted from the beam nozzle 13, so as to be aligned with the emission direction of the laser beam 23.

[0027] The surroundings of the processing point 22 to which the wire 5 is supplied by the wire nozzle 14 are isolated from the atmosphere by the shielding gas 24 sprayed by the shielding gas nozzle 15 .

[0028] A gas can be used as the shielding gas 24. In particular, an inert gas may be used as the shielding gas 24 to suppress oxidation. Examples of inert gases used as the shielding gas 24 include helium gas, argon gas, and nitrogen gas. Carbon dioxide gas may also be used as the shielding gas 24 as long as it is a gas other than an inert gas. The shielding gas 24 may be at least one of the above. In the first embodiment, an inert gas is used as the shielding gas 24 to suppress oxidation.

[0029] The cooling nozzle 11, which is a cooling unit, sprays a cooling medium 25 toward the object to cool it. As shown in FIG. 1, the cooling nozzle 11 sprays the cooling medium 25 toward the processing point 22. A cooling medium spraying mechanism that sprays the cooling medium 25 is configured by a cooling medium supply device 9, a cooling medium piping 10, and the cooling nozzle 11. As shown in FIG. 2, the cooling nozzle 11 is connected to a cooling medium supply device 9 that supplies the cooling medium 25 via the cooling medium piping 10. The cooling medium 25 is sprayed from the cooling nozzle 11, and is transmitted from the cooling medium supply device 9 through the cooling medium piping 10 to the cooling nozzle 11 fixed to the processing head 12.

[0030] The cooling medium 25 may be a gas, a liquid, or a solid. An inert gas may be used as the cooling medium 25. Examples of the inert gas used as the cooling medium 25 include helium gas, argon gas, and nitrogen gas. Carbon dioxide gas may also be used as the cooling medium 25 as long as it is a gas other than an inert gas. Other examples of the cooling medium 25 include liquid nitrogen, dry ice, and water. The cooling medium 25 may be at least one of the above. In the first embodiment, an inert gas is used as the cooling medium 25.

[0031] An inert gas is preferably used as the cooling medium 25 to prevent oxidation of the molded object, and the type of gas can be selected from various perspectives. Here, examples of characteristic gases are described. For example, helium has a high heat transfer coefficient and a high cooling effect even at low flow rates. Argon is the most commonly used in molding among inert gases, and is easily available and has low reactivity, making it effective at preventing oxidation. Nitrogen is also economically advantageous because it is industrially available at low cost compared to helium and argon. In particular, nitrogen has good cooling efficiency when sprayed at high flow rates for rapid cooling, is inexpensive to obtain, and is the most compatible with the present disclosure. In addition to inert gases, low-temperature cooling mediums 25 such as dry ice and liquid nitrogen may also be used, and the desired effect can be achieved by combining these media.

[0032] In the metal additive manufacturing apparatus 100 of the first embodiment, the processing head 12 moves relative to the stage 17. The processing head 12 is moved by a head driving device 16. The stage 17 is moved by a rotation device 18. The processing head 12, the head driving device 16, the stage 17, and the rotation device 18 constitute a movement mechanism that moves the processing head 12 and the stage 17 relative to each other. Note that this mechanism is one example and is not limited to the present disclosure.

[0033] As shown in FIG. 2 , the stage 17 is equipped with a rotation device 18 and carries a model. A base material 19 is placed on the stage 17, and a bead 20 is deposited on the base material 19. The stage 17 is rotated or moved by the rotation device 18, thereby changing the posture or position of the model. In other words, by moving the stage 17, it is possible to move it relative to the processing head 12. By providing the stage 17 with the rotation device 18, the metal additive manufacturing apparatus 100 of this embodiment is able to manufacture complex shapes, including tapered shapes.

[0034] As shown in Fig. 2, the metal additive manufacturing apparatus 100 according to the first embodiment includes a control device 1 that controls the operation of the metal additive manufacturing apparatus 100 in accordance with a program related to processing and cooling. The control device 1 controls the wire supply mechanism, heating mechanism, shielding gas spraying mechanism, cooling medium spraying mechanism, and movement mechanism. For example, a numerical control device is used as the control device 1. The control device 1 controls the operation of the manufacturing apparatus 100 by outputting various commands.

[0035] In the wire supply mechanism, the control device 1 controls the rotary motor 4 by outputting a command to the rotary motor 4 according to the material supply rate. The control device 1 controls the rotary motor 4 to adjust the speed at which the wire 5 is supplied from the wire spool 6 to the processing point 22. In the heating mechanism, the control device 1 controls the laser oscillator 2 by outputting a command to the laser oscillator 2 according to the beam output rate, thereby controlling the laser oscillation of the laser oscillator 2 and causing the laser beam 23 to be emitted from the beam nozzle 13. In the shielding gas spraying mechanism, the control device 1 controls the supply rate of the shielding gas 24 from the shielding gas supply device 7 by outputting a command to the shielding gas supply device 7 according to the supply rate of the shielding gas 24, thereby spraying the shielding gas 24 from the shielding gas nozzle 15. In the cooling medium spraying mechanism, the control device 1 controls the supply rate of the cooling medium 25 from the cooling medium supply device 9 by outputting a command to the cooling medium supply device 9 according to the supply rate of the cooling medium 25, thereby spraying the cooling medium 25 from the cooling nozzle 11. For the machining head 12 of the moving mechanism, the control device 1 outputs a movement command to the head drive device 16, thereby controlling the drive of the head drive device 16 and moving the machining head 12. For the stage 17 of the moving mechanism, the control device 1 outputs a rotation command to the rotation device 18, thereby controlling the drive of the rotation device 18 and moving the stage 17. Furthermore, in order to form a desired shape, the control device 1 controls the moving mechanism, thereby moving the machining head 12 and the stage 17 relatively.

[0036] Here, we will explain the hardware configuration of the control device 1. The control of the control device 1 shown in Fig. 2 is realized by executing, in hardware, a control program that is a program for executing control of the manufacturing apparatus 100 of the first embodiment.

[0037] 3 is a block diagram showing a hardware configuration of the control device 1 according to embodiment 1. The control device 1 has a CPU (Central Processing Unit) 41 that executes various processes, a RAM (Random Access Memory) 42 that includes a data storage area, a ROM (Read Only Memory) 43 that is a non-volatile memory, an external storage device 44, and an input / output interface 45 for inputting information to the control device 1 and outputting information from the control device 1. The components shown in FIG. 3 are interconnected via a bus 46.

[0038] The CPU 41 executes programs stored in the ROM 43 and the external storage device 44. The overall control of the metal additive manufacturing apparatus 100 by the control device 1 is realized using the CPU 41.

[0039] The external storage device 44 is an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The external storage device 44 stores a control program and various data. The ROM 43 stores a boot loader such as BIOS (Basic Input / Output System) or UEFI (Unified Extensible Firmware Interface), which is a basic control program for the computer or controller that is the control device 1, and software or a program that controls the hardware. The control program may be stored in the ROM 43.

[0040] The programs stored in the ROM 43 and the external storage device 44 are loaded into the RAM 42. The CPU 41 deploys the control programs in the RAM 42 and executes various processes. The input / output interface 45 is an interface for connecting the control device 1 to devices external to the control device 1. A machining program is input to the input / output interface 45. The input / output interface 45 also outputs various commands. The control device 1 may have input devices such as a keyboard and a pointing device, and an output device such as a display.

[0041] The control program may be stored in a computer-readable storage medium. The control device 1 may store the control program stored in the storage medium in the external storage device 44. 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 1 from another computer or server device via a communication network.

[0042] The functions of the control device 1 may be realized by a processing circuit, which is dedicated hardware for controlling the metal additive manufacturing apparatus 100. 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 1 may be realized by dedicated hardware, and other parts may be realized by software or firmware.

[0043] Next, the operation of the metal additive manufacturing apparatus 100 and a method for manufacturing a metal additive manufacturing object using the manufacturing apparatus 100 according to the first embodiment will be described.

[0044] The method for manufacturing a metal additive manufacturing object according to the first embodiment is a manufacturing method in which a manufacturing step is repeated, and includes a manufacturing step and a cooling step.

[0045] In the manufacturing process, while a shielding gas 24 is sprayed from the shielding gas nozzle 15, the beam nozzle 13, which moves relatively to the stage 17 on which the object is placed, emits a laser beam 23 to heat the wire 5 supplied by the wire nozzle 14 along a first path on the object. The first path on the object is a path in the manufacturing process in which the beam nozzle 13 moves relatively to the stage 17 along a predetermined path, and the beam nozzle 13 emits the laser beam 23 onto the object to heat the wire 5. The first path on the object is a path along which the beam nozzle 13 moves relatively to the stage 17 along a predetermined path. a The modeling path R a is also the path taken by the processing point 22. Then, a bead 20, which is the wire 5 melted by the beam nozzle 13, is deposited on the object, forming a desired shape.

[0046] In the modeling process, the modeling conditions are determined by the laser output conditions selected from the raw material of the wire 5, the supply amount of the wire 5, and the axial movement speed of the wire nozzle 14 and the beam nozzle 13 fixed to the processing head 12. In addition, the modeling path R is determined depending on the shape of the desired model. a is determined, and the modeling path R a is determined for each modeling process. The modeling process is repeated multiple times, but the modeling path R a may be the same or may be different.

[0047] In the cooling step, before the next modeling step, the beam nozzle 13 stops emitting the laser beam 23, and the cooling nozzle 11, which moves relatively to the stage 17, sprays the cooling medium 25 onto the model to cool it along a second path on the model. The second path on the model is a path in which the cooling nozzle 11 moves relatively to the stage 17 in the cooling step and sprays the cooling medium 25 onto the model to cool it. The second path on the model is called cooling path R c Cooling path R c is the modeling path R aThe cooling nozzle 11 fixed to the processing head 12 sprays the cooling medium 25 toward the processing point 22 in the molding process, so in the cooling process, the cooling nozzle 11 follows the molding path R, which is the path of the processing point 22 in the molding process. a The cooling medium 25 can be sprayed toward the molding path R a The locus of the laser beam 23 is the location on the object that is heated by the beam nozzle 13 during the modeling process. c The trajectory of the cooling path R is the location where the cooling nozzle 11 sprays the cooling medium 25 onto the object during the cooling process. c is the modeling path R a By having the same or opposite direction as the cooling path R c The trajectory of the modeling path R a This coincides with the trajectory of the cooling water, allowing the object to be cooled sufficiently.

[0048] The axial movement speed of the cooling nozzle 11 fixed to the processing head 12 in the cooling process may be the same as or different from the axial movement speed of the wire nozzle 14 and the beam nozzle 13 in the modeling process. Then, when the cooling process is completed, the modeling process starts from the modeling start position for the next layer.

[0049] Furthermore, during the cooling process, the wire nozzle 14 stops supplying the wire 5. For example, during the cooling process, the wire 5 supplied from the wire nozzle 14 may be wound by the rotary motor 4 and stored in the wire spool 6, thereby stopping the wire nozzle 14 from supplying the wire 5. Another method for stopping the supply of the wire 5 may be to retract the wire nozzle 14 to a position where the cooling medium 25 sprayed from the cooling nozzle 11 does not hit the wire 5.

[0050] In the cooling step, the shielding gas nozzle 15 continues to spray the shielding gas 24 onto the shaped object in the same manner as in the shaping step, without stopping the spraying.

[0051] The flow rate of the cooling medium 25 sprayed by the cooling nozzle 11 in the cooling process is greater than the flow rate of the shielding gas 24 in the manufacturing process. The shielding gas nozzle 15 in the manufacturing process adjusts the flow rate of the shielding gas 24 so that the shielding gas 24 becomes a laminar flow that does not entrain surrounding oxygen. On the other hand, the cooling nozzle 11 in the cooling process sprays the cooling medium 25 at a higher flow rate so that the cooling medium 25 becomes a turbulent flow. In the cooling process, the higher flow rate of the cooling medium 25 allows the molded object to be cooled more quickly.

[0052] Up to this point, an example has been described in which the machining point 22 and the position where the cooling nozzle 11 blows are the same. c is the modeling path R a In some cases, it is not necessary for the cooling nozzle 11 to spray the cooling medium 25 toward the processing point 22 so that the direction is the same as or opposite to that of the cooling nozzle 11. A specific example of this will be described later with reference to Example 2.

[0053] As described above, the metal additive manufacturing apparatus 100 according to the first embodiment comprises a wire nozzle 14 that supplies wire 5, a beam nozzle 13 that emits a laser beam 23 to heat the wire 5, a stage 17 that moves relative to the beam nozzle 13 and on which a molded object is placed on which the beam nozzle 13 deposits a bead 20 formed by melting the wire 5, a shielding gas nozzle 15 that sprays shielding gas 24 toward a processing point 22, a cooling nozzle 11 that moves relative to the stage 17 and sprays a cooling medium 25 toward the processing point 22, and a control device 1 that controls the beam nozzle 13 to move relative to the stage 17 while heating the wire 5 along a first path on the molded object, and then stopping the heating of the beam nozzle 13 and moving the cooling nozzle 11 relative to the stage 17 while spraying a cooling medium 25 along a second path on the molded object that is the same as or opposite to the first path to cool the molded object.

[0054] As a result, in the metal additive manufacturing apparatus 100 according to the first embodiment, the beam nozzle 13 moves relative to the stage 17, and the bead 20 can be deposited in a desired shape on the object. Furthermore, during the manufacturing process, the beam nozzle 13 heats the wire 5, and during the cooling process, the beam nozzle 13 stops emitting the laser beam 23 to heat the wire, and the cooling nozzle 11 cools the object. This suppresses interference between the shielding gas 24 and the cooling medium 25 during the manufacturing process. Suppressing interference between the shielding gas 24 and the cooling medium 25 during the manufacturing process prevents disturbance of the shielding gas 24 during the manufacturing process, making the object less susceptible to oxidation. Furthermore, preventing the cooling medium 25 from being entrained prevents gas pores from forming inside the object. This allows for the production of high-quality objects.

[0055] The cooling nozzle 11 sprays the cooling medium 25 toward the processing point 22, thereby forming a cooling path R c The printing path R a The second path on the part can be the same as or opposite to the first path on the part, so that the cooling path R c Trajectory and modeling path R a This reduces the number of parts of the object that are not hit by the cooling medium 25 or that are not sufficiently cooled, resulting in a high-quality object.

[0056] Furthermore, in the metal additive manufacturing apparatus 100 according to the first embodiment, the shielding gas nozzle 15 is coaxial with the beam nozzle 13. As shown in FIG. 1 , the spray direction of the shielding gas nozzle 15, which is disposed coaxially with the beam nozzle 13, is the same as the direction in which the beam nozzle 13 emits the laser beam 23. As shown in FIG. 1 , assume that the direction in which the shielding gas nozzle 15 sprays the shielding gas 24 is perpendicular to the installation surface of the stage 17. In this case, because the direction in which the shielding gas nozzle 15 sprays the shielding gas 24 is the same as the direction in which the beam nozzle 13 emits the laser beam 23, the shielding gas 24 is sprayed symmetrically with respect to the processing point 22. This reduces the areas of the object where the shielding gas 24 is not easily incident, further suppressing oxidation of the object and resulting in a high-quality object.

[0057] The method for manufacturing a metal additive manufacturing object according to the first embodiment is a manufacturing method that repeats a manufacturing process, and includes a manufacturing process and a cooling process. In the manufacturing process, a shielding gas 24 is sprayed from a shielding gas nozzle 15, and a laser beam 23 is emitted while a beam nozzle 13 moves relative to a stage 17 on which a molded object is placed, and a wire 5 supplied by a wire nozzle 14 is guided along a manufacturing path R. a Then, a bead 20, which is the wire 5 melted by the beam nozzle 13, is deposited on the object to form the model. In the cooling process, before the next modeling process, the beam nozzle 13 stops emitting the laser beam 23, and a cooling medium 25 is sprayed from the cooling nozzle 11, which moves relatively to the stage 17, to form a cooling path R. c Cooling path R c is the modeling path R a The same or opposite route.

[0058] By separating the molding process from the cooling process, interference between the shield gas 24 and the cooling medium 25 during the molding process can be suppressed, and a high-quality molded object can be obtained.

[0059] Furthermore, by performing cooling in a cooling process separate from the modeling process, the cooling medium 25 can be sprayed without restriction during the cooling process, further enhancing the cooling effect. Cooling by the cooling medium 25 is achieved by heat transfer between the medium gas and the model, and the amount of heat transfer is generally expressed as the product of the flow rate of the cooling medium 25 and the difference between the temperature of the model and the temperature of the cooling medium gas. Therefore, the greater the flow rate of the cooling medium 25, the greater the amount of heat transfer and the higher the cooling effect. Furthermore, when the cooling medium 25 is sprayed strongly, the flow becomes turbulent, and turbulent flow has a higher heat transfer rate than laminar flow, so the cooling effect can be improved from this perspective as well.

[0060] By increasing the cooling effect, heat accumulation in the model can be suppressed. However, suppressing heat accumulation has several effects. The first effect is to suppress the shape collapse due to heat accumulation. s and build end point A f Corners such as these tend to accumulate heat, causing the shape of the molded object to sag. In the first embodiment, performing a cooling process after the molding process prevents heat accumulation, thereby improving the accuracy of the molded shape. The second effect is stabilization of the molding conditions. The molding conditions are stabilized by maintaining a constant base temperature of the molded object. Normally, heat accumulation in the molded object can cause overheating at the initial output of the laser beam 23, requiring control such as reducing the output of the laser beam 23. However, in the first embodiment, heat accumulation can be suppressed by cooling the molded object in the cooling process, so the molding conditions do not change even as the molding progresses, and the molding conditions can be stabilized. The third effect is stabilization of the molded object's structure. It is known that the strength of a metal structure decreases as the crystal grain size increases. Heating a metal structure causes the crystal grains to coarsen, and heat accumulation gradually coarsens the metal structure of the molded object. In the first embodiment, removing heat from the molded object in the cooling process suppresses coarsening of the metal structure, thereby stabilizing the structure of the molded object.

[0061] In this way, by cooling the object in a cooling process that is separate from the molding process, it is possible to spray the cooling medium 25 without any restrictions during the cooling process, which makes it possible to suppress heat accumulation and obtain a high-quality object.

[0062] In the first embodiment, the flow rate of the coolant 25 is greater than the flow rate of the shielding gas 24, but the flow rate of the coolant 25 may be the same as the flow rate of the shielding gas 24. In other words, the flow rate of the coolant 25 may be equal to or greater than the flow rate of the shielding gas 24.

[0063] Furthermore, the metal additive manufacturing apparatus 100 according to embodiment 1 has a processing head 12 to which the wire nozzle 14, the beam nozzle 13, the wire nozzle 14, and the shielding gas nozzle 15 are fixed, but the processing head 12 itself may not be present, and the wire nozzle 14, the beam nozzle 13, the wire nozzle 14, and the shielding gas nozzle 15 may each be provided directly on the manufacturing apparatus 100.

[0064] In addition, in embodiment 1, the beam nozzle 13 and the shielding gas nozzle 15 are provided as separate nozzles, but the beam nozzle 13 and the shielding gas nozzle 15 may be the same, and the laser beam 23 and the shielding gas 24 may pass through the same nozzle.

[0065] Furthermore, in the first embodiment, the shielding gas nozzle 15 is provided coaxially with the beam nozzle 13 and sprays the shielding gas 24 along the emission direction of the laser beam 23 emitted from the beam nozzle 13, but this is not limitative. For example, the shielding gas nozzle 15 may spray the shielding gas 24 from a direction oblique to the emission direction of the laser beam 23 emitted from the beam nozzle 13.

[0066] Furthermore, in the first embodiment, the shielding gas nozzle 15 sprays the shielding gas 24 in the cooling step, but the shielding gas nozzle 15 may stop spraying the shielding gas 24 in the cooling step.

[0067] Furthermore, in the first embodiment, the base material 19 is a plate material, but the base material 19 may be a material other than a plate material.

[0068] A specific example will be described below.

[0069] Example 1 The operation of the metal additive manufacturing apparatus 100 according to Example 1 and a method for manufacturing a metal additive manufacturing object using the manufacturing apparatus 100 will be described. Fig. 4 is a schematic diagram showing a molded object manufactured by the metal additive manufacturing apparatus 100 according to Example 1. Example 1 will be described using an example in which a rectangular shape as shown in Fig. 4 is molded.

[0070] The installation position of the cooling nozzle 11 of the metal additive manufacturing apparatus 100 according to Example 1 will be described. In Example 1, as shown in Fig. 1 , the cooling nozzle 11 is installed so that it sprays a cooling medium 25 toward a processing point 22 in the manufacturing process. In Example 1, the stage 17 is not moved, and the manufacturing process and cooling process are performed by moving the processing head 12 to which the wire nozzle 14, beam nozzle 13, shield gas nozzle 15, and cooling nozzle 11 are fixed.

[0071] FIG. 5 shows a modeling path R in a model manufactured by the metal additive manufacturing apparatus 100 according to the first embodiment. a and cooling path R c 5 is a schematic diagram showing the trajectory of the rectangular object shown in FIG. 4 as viewed from above. FIG. 5(a) shows the trajectory of the object manufactured by the metal additive manufacturing apparatus 100 according to the first embodiment. a 5(a) is a schematic diagram showing the trajectory of the cooling path R in the molded object manufactured by the metal additive manufacturing apparatus 100 according to the first embodiment. c As shown in FIG. 5(a), in the modeling process, s and end point A f and the starting point of the modeling is A s From the end point A f Towards the modeling path R aAs shown in FIG. 5(b), in the cooling process, the cooling start point C s and the cooling end point C f The cooling start point C s From the cooling end point C f Cooling path R c is stated.

[0072] Fig. 6 is a flowchart showing the operation of the metal additive manufacturing apparatus 100 and the method for manufacturing a metal additive manufacturing object according to Example 1. As shown in Fig. 6, the metal additive manufacturing apparatus 100 performs a manufacturing path generation step S0 before starting manufacturing, and then repeats a manufacturing step S10 and a cooling step S20.

[0073] First, in order to manufacture a desired object, step S0 is performed to generate a manufacturing path. The manufacturing process is performed multiple times to manufacture a metal additive manufacturing object, and step S10, which is the manufacturing process for the Nth layer, is performed based on the path generated in step S0. In step S10, the processing head 12, to which the wire nozzle 14, beam nozzle 13, and shield gas nozzle 15 are fixed, moves along the manufacturing path R in accordance with the manufacturing conditions arbitrarily determined depending on the material of the wire 5. a The model is created while moving.

[0074] After step S10 is completed, step S20, which is a cooling step for the Nth layer, is performed. In step S20, the operations of the wire nozzle 14 and the beam nozzle 13 are stopped, and the processing head 12 is stopped at the modeling end point A f From the starting point A s The cooling nozzle 11 is fixed to the processing head 12, and the cooling nozzle 11 is positioned at the cooling start point C s From the cooling end point C f Cooling path R up to c As shown in FIG. 5, in the first embodiment, the cooling path R c is the modeling path R aIn step S20, the shielding gas nozzle 15 continues to spray the shielding gas 24. In step S20, the cooling nozzle 11 sprays the cooling medium 25 toward the processing point 22 in the manufacturing process, and the position where the cooling nozzle 11 sprays the cooling medium 25 onto the object in the cooling process coincides with the position where the beam nozzle 13 emits the laser beam 23 onto the object to heat it in the manufacturing process. As a result, the manufacturing path R a trajectory and cooling path R c The trajectory of

[0075] And the cooling end point C f After the processing head 12 has moved to the next layer, the spraying of the cooling medium 25 from the cooling nozzle 11 is stopped, and step S20 is completed. Upon completion of step S20, the process proceeds to step S10, which is the modeling process for the (N+1)th layer. Then, the modeling process and the cooling process are repeated in the same manner. By repeating the modeling process and the cooling process in this manner, heat accumulation in the modeled object can be suppressed.

[0076] In the first embodiment, the cooling nozzle 11 in the cooling process sprays the cooling medium 25 toward the processing point 22 in the modeling process, thereby forming the modeling path R a trajectory and cooling path R c This allows the cooling nozzle 11 to cool the part that has been molded into the desired shape. a trajectory and cooling path R c The case where the locus does not match will be explained in the following Comparative Example 1.

[0077] (Comparative Example 1) Comparative Example 1 is a shaping path R a trajectory and cooling path R c This is an example of a case where the trajectory of the cooling nozzle 11 does not match the trajectory of the cooling nozzle 11 in the molding process. Comparative Example 1 will be described using an example of a metal additive manufacturing device disclosed in Patent Document 1, in which the cooling nozzle 11 is arranged behind the processing point 22. In Comparative Example 1, the cooling nozzle 11 in the cooling process does not spray the cooling medium 25 toward the processing point 22 in the molding process.

[0078] In Comparative Example 1, similar to Example 1, a rectangular shape as shown in Fig. 4 is manufactured. Therefore, in Comparative Example 1, the stage 17 is not moved, but the processing head 12 is moved to perform the manufacturing process and the cooling process. The manufacturing method and steps of the metal additive manufacturing object in Comparative Example 1 were performed in the same order as in Example 1.

[0079] FIG. 7 shows the manufacturing path R of the object manufactured by the metal additive manufacturing apparatus according to Comparative Example 1. a and cooling path R c 7(a) is a schematic diagram showing the trajectory of the metal additive manufacturing path R in a metal additive manufacturing object produced by the metal additive manufacturing apparatus according to Comparative Example 1. a 7(b) is a schematic diagram showing the trajectory of the cooling path R in a molded object manufactured by the metal additive manufacturing apparatus according to Comparative Example 1. c 6 is a schematic diagram showing the path of the cooling path R. In Comparative Example 1, as in Example 1, step S10 was performed after step S0, and then step S20 was performed, as shown in FIG. c The trajectory of the modeling path R a The cooling path R c The trajectory of the modeling path R a As a result, there were areas on the object where the cooling medium 25 did not reach, and the object could not be cooled sufficiently. In this way, in the case of an object having a rectangular shape, if the position where the beam nozzle 13 emits the laser beam 23 onto the object to heat it in the modeling process and the position where the cooling nozzle 11 sprays the cooling medium 25 onto the object in the cooling process do not match, the object cannot be cooled sufficiently.

[0080] Comparing Example 1 with Comparative Example 1, it was found that it is effective for the cooling nozzle 11 in the cooling step to spray the cooling medium 25 toward the processing point 22 in the shaping step.

[0081] Example 2 In Example 1 and Comparative Example 1, the molding of a rectangular shape was described. On the other hand, depending on the shape of the metal additive manufacturing object, the molding path R may be formed even if the cooling nozzle 11 in the cooling step does not spray the cooling medium 25 toward the processing point 22 in the molding step. a trajectory and cooling path R c In the second embodiment, even if the cooling nozzle 11 in the cooling process does not spray the cooling medium 25 toward the processing point 22 in the modeling process, the modeling path R a trajectory and cooling path R c 8 is a schematic diagram showing a molded object manufactured by the metal additive manufacturing apparatus according to Example 2. Example 2 will be described using an example of molding a cylindrical shape as shown in FIG.

[0082] Like Comparative Example 1, Example 2 is an example using a metal additive manufacturing device disclosed in Patent Document 1, in which a cooling nozzle 11 is disposed behind a processing point 22. Unlike Example 1 and Comparative Example 1, Example 2 does not move the processing head 12, but instead rotates the stage 17 to perform the molding. In Example 2, the molding process and cooling process are performed by rotating the stage 17 around the center of the circular cross section of the cylindrical shape shown in FIG. 8 as the central axis. In the case of a simple, symmetrical shape such as a cylinder, it is possible to perform the molding with the processing head 12 fixed.

[0083] FIG. 9 shows a modeling path R in a model manufactured by the metal additive manufacturing apparatus according to Example 2. a and cooling path R c 9 is a schematic diagram showing the trajectory of the metal additive manufacturing process for the cylindrical object shown in FIG. 8, as viewed from above. FIG. 9(a) shows the trajectory of the metal additive manufacturing process for the cylindrical object produced by the metal additive manufacturing apparatus according to Example 2. a 9(b) is a schematic diagram showing the trajectory of the cooling path R in the molded object manufactured by the metal additive manufacturing apparatus according to Example 2. c In Example 2, as shown in FIG. 9, s and end point A fAs shown in the flowchart of FIG. 6, in Example 2, step S10 is performed after step S0, and then step S20 is performed. As a result, as shown in FIG. 9, in the case of a cylindrical shape, the printing start point A s and the cooling start point C s In other words, the modeling path R a Starting position and cooling path R c However, the starting position of the printing path R a and cooling path R c Although the starting position was different from that of the previous example, the cooling path R c The trajectory of the modeling path R a Therefore, in the manufacturing of a cylindrical object, the manufacturing path R a trajectory and cooling path R c The trajectory of

[0084] In the second embodiment, a cylindrical object is manufactured. However, even if the cooling nozzle 11 in the cooling step does not spray the cooling medium 25 toward the processing point 22 in the manufacturing step, the manufacturing path R a trajectory and cooling path R c The shape that matches the locus of is not limited to a cylindrical shape.

[0085] From Example 2, in the case of a simple and symmetrical shape such as a cylindrical shape, the cooling path R can be formed without the cooling nozzle 11 in the cooling process spraying the cooling medium 25 toward the processing point 22 in the molding process. c The trajectory of the modeling path R a However, Example 2 is a special case, and spraying the cooling medium 25 from the cooling nozzle 11 in the cooling process toward the processing point 22 in the modeling process as in Example 1 makes it possible to appropriately cool a modeled object of a desired shape, including a complex shape.

[0086] Embodiment 2 Next, a description will be given of embodiment 2. Fig. 10 is a schematic cross-sectional view showing a metal additive manufacturing apparatus 200 according to example 3 of embodiment 2. Note that the same components as those in embodiment 1 are given the same reference numerals, and the description thereof will be omitted.

[0087] The metal additive manufacturing apparatus 200 according to the second embodiment differs from the first embodiment in that it is equipped with a temperature measuring instrument .

[0088] The temperature measuring instrument 28 used in this embodiment can be a non-contact type such as a radiation thermometer or a thermoviewer. Alternatively, the temperature measuring instrument 28 can be a contact type such as a thermocouple. Typically, since the temperature of the object to be formed reaches high temperatures, a non-contact type is often used, as it is easy to use. In particular, when measuring the temperature of the entire object, it is preferable to use a non-contact type as the temperature measuring instrument 28. However, a non-contact type may not be able to measure the temperature accurately because the emissivity changes depending on the surface condition of the material. In the present disclosure, the object can be cooled by the cooling process, and accurate measurement is also possible by using a contact type thermocouple as the temperature measuring instrument 28.

[0089] The method for manufacturing a metal additive manufacturing object according to the second embodiment is also different from the first embodiment in that it includes a temperature measurement step in which a temperature gauge 28 is used to measure the temperature of the object.

[0090] The method for manufacturing a metal additive manufacturing object according to the second embodiment includes a temperature measurement step in which, before the next modeling step, the laser beam 23 of the beam nozzle 13 is stopped and the temperature of the model is measured using the temperature gauge 28. In the temperature measurement step, the temperature of the model is measured using the temperature gauge 28, and if the measurement result is below a predetermined temperature, the modeling step is carried out next, and if the measurement result is above the predetermined temperature, the cooling step is carried out next. The predetermined temperature is set to a temperature that is not too high so as to suppress heat accumulation. The temperature gauge 28 is also controlled by the control device 1. The measurement results of the temperature gauge 28 are input to the control device 1, and the control device 1 controls the selection of the next processing step based on the measurement results.

[0091] Regarding the temperature measurement process, the positions on the model where the temperature gauge 28 measures the temperature are as follows. The first is when the temperature is measured at the modeling start position on the model during the modeling process. In this case, by providing the temperature measurement process, it is possible to prevent modeling from starting while heat is still accumulated.

[0092] The second method is to measure the temperature of the entire object. In this case, the temperature measurement process can identify areas of heat accumulation throughout the entire object. If the measurement result of the temperature gauge 28 at a specific area of ​​the object is higher than a predetermined temperature, the cooling process involves spraying the cooling medium 25 from the cooling nozzle 11 onto the area of ​​the object where the measurement result of the temperature gauge 28 is higher than the predetermined temperature to cool it. This makes it possible to cool only the heat accumulation areas of the object that are found to have high temperatures by measuring the temperature of the object, rather than cooling the entire object, thereby suppressing cooling of areas that do not need to be cooled.

[0093] As described above, the metal additive manufacturing apparatus 200 according to the second embodiment is equipped with the temperature measuring device 28, and thus it is possible to measure the temperature of the object and determine whether the object is accumulating heat.

[0094] Furthermore, the manufacturing method of a metal additive manufacturing object according to the second embodiment includes a temperature measurement step in which, before the next modeling step, the laser beam 23 of the beam nozzle 13 is stopped and the temperature of the model is measured using a temperature gauge 28. If the measurement result of the temperature gauge 28 is equal to or lower than a predetermined temperature, the modeling step is carried out, and if the measurement result of the temperature gauge 28 is higher than the predetermined temperature, the cooling step is carried out.

[0095] In this way, whether the next process is a modeling process or a cooling process can be determined based on the measurement results of the temperature gauge 28, making it possible to reduce unnecessary cooling processes. Furthermore, in actual modeling, it is necessary to manage the base temperature of the object to stabilize the modeling conditions, but in the manufacturing method for a metal additive manufacturing object according to embodiment 2, by measuring the temperature of the object, it is possible to sufficiently stabilize the base temperature of the object before modeling, thereby stabilizing the metal structure of the object and the modeling conditions.

[0096] Furthermore, when the temperature of the object at the modeling start position during the modeling process is measured in the temperature measurement step, it is possible to prevent modeling from starting while heat is still accumulated.

[0097] Furthermore, if the temperature of the entire object is measured in the temperature measurement step, it is possible to find parts of the object that are at a temperature higher than a predetermined value. Furthermore, by cooling parts of the object that are at a temperature higher than a predetermined value in the cooling step, it is possible to achieve efficient cooling without having to cool the entire object.

[0098] In addition, the cooling path R c is the molding path R in the molding process. a The cooling path R does not have to be the same as or opposite to all of the above. c is the modeling path R a In order to more efficiently cool the heat accumulation portion of the object, the movement of the cooling nozzle 11 relative to the object in the cooling step does not have to be the same as the movement of the beam nozzle 13 relative to the object in the modeling step, and the cooling nozzle 11 may move the shortest distance toward the portion to be cooled.

[0099] A specific example will be described below.

[0100] Example 3 Example 3 is an example of a manufacturing method that, in addition to Example 1, further includes a temperature measurement step.

[0101] In Example 3, similar to Example 1, a rectangular shape as shown in Fig. 4 is formed. In Example 3, similar to Example 1, the stage 17 is not moved, but the processing head 12 is moved to perform the forming process and the cooling process.

[0102] The installation position of the temperature measuring device 28 of the metal additive manufacturing apparatus 200 according to the third embodiment will be described. In the third embodiment, as shown in FIG. 10, the temperature measuring device 28 uses a thermocouple. s The temperature measuring device 28 may be installed so as to be able to measure the temperature of the processing point 22 in the modeling process. The temperature measuring device 28 may also be fixed to the processing head 12.

[0103] 11 is a flowchart showing the operation of the metal additive manufacturing apparatus 200 and the method for manufacturing a metal additive manufacturing object according to Example 3. FIG. a and cooling path R c 12(a) is a schematic diagram showing the trajectory of the metal additive manufacturing object produced by the metal additive manufacturing apparatus 200 according to the third embodiment. a 12(b) is a schematic diagram showing the trajectory of the cooling path R in the molded object manufactured by the metal additive manufacturing apparatus 200 according to the third embodiment. c 11, the manufacturing method of a metal additive manufacturing object of this embodiment first performs step S0 of generating a modeling path before starting the modeling process in order to manufacture a desired object. Step S10, which is the modeling process for the Nth layer, is performed based on the path generated in step S0. In step S10, the temperature measuring device 28 is retracted to a position where it will not be hit by the laser beam 23, for example, above or beside the processing head 12.

[0104] After step S10 is completed, step S30, which is a temperature measurement step, is performed. Before step S30, as shown by the dashed line in FIG. 12(a), the processing head 12 is f From the starting point A sMove in a straight line to the starting point A of the printing by the shortest route. s At this time, since there is no need to cool the part to be molded, the processing head 12 does not need to move along the object to be molded. In step S30, the operations of the wire nozzle 14, the beam nozzle 13, and the shield gas nozzle 15 are stopped, and the temperature at the mold starting point A is measured using a thermocouple, which is a temperature measuring instrument 28. s If the flow rate of the shielding gas 24 sprayed from the shielding gas nozzle 15 does not affect the temperature measurement, the shielding gas nozzle 15 may spray the shielding gas 24 in step S30.

[0105] Here, the next process differs depending on the measurement result of the temperature gauge 28 in step S30. If the measurement result of the temperature gauge 28 is equal to or lower than a predetermined temperature, the process does not proceed to step S20, which is the cooling process for the Nth layer, but rather to step S10, which is the modeling process for the (N+1)th layer. The predetermined temperature here can be determined arbitrarily depending on the purpose and material, such as oxidation suppression, structure stabilization, and heat sagging suppression. On the other hand, if the measurement result of the temperature gauge 28 is higher than the predetermined temperature, step S20 is performed. In step S20, as shown in FIG. 12(b), the cooling nozzle 11 cools the cooling nozzle 11 at the cooling start point C s From the cooling end point C f Cooling path R up to c The cooling path R c is the modeling path R a When step S20 is completed, the processing head 12 is moved to the modeling start point A s Then, step S30 is performed again, and depending on the measurement result of the temperature measuring instrument 28, the process proceeds to step S10 or step S20.

[0106] As described above, in Example 3, by measuring the temperature of the molded object, it is possible to reduce the number of unnecessary cooling steps compared to Example 1. Note that, although Step S30 is performed after Step S10 in Example 3, if it is known that the heat accumulation will not be sufficient to raise the temperature of the molded object to a predetermined temperature, Step S10 may be repeated multiple times without Step S30 being performed.

[0107] Example 4 Example 4 is an example of a manufacturing method in which the temperature measurement step is performed after the cooling step when the molded object cannot be cooled to the desired temperature due to continuous molding.

[0108] FIG. 13 is a flowchart showing the operation of the metal additive manufacturing apparatus 200 and the method for manufacturing a metal additive manufacturing object according to Example 4. While Example 3 was an example in which the temperature measurement process was performed after the modeling process was performed consecutively, Example 4, as shown in FIG. 13, is an example in which the cooling process is performed after the modeling process, and then the temperature measurement process is performed. That is, Example 4 differs from Example 3 in that the temperature measurement process is performed after the cooling process. In Example 4, as shown in the flowchart in FIG. 13, step S20 is performed after step S10, and then step S30 is performed. In step S30, as in Example 3, if the measurement result of the temperature gauge 28 is equal to or lower than the predetermined temperature, step S10 is performed, and if the measurement result of the temperature gauge 28 is higher than the predetermined temperature, step S20 is performed next. After step S20, step S30 is performed again, and either step S10 or step S20 is performed depending on the measurement result of the temperature gauge 28.

[0109] In this way, by performing the temperature measurement step after the cooling step and continuing the cooling step if the temperature of the printed object has not dropped sufficiently, heat accumulation in the printed object can be suppressed in Example 4. Furthermore, in Example 4, performing the cooling step before the temperature measurement step makes it difficult for the printed object to become too hot, so a contact-type thermocouple can be used as the temperature measuring device 28. Furthermore, by combining Example 3 and Example 4, when heat accumulation is low, unnecessary cooling steps can be reduced as in Example 3 to increase printing efficiency, and when heat accumulation is high, the number of cooling steps can be increased as in Example 4, and the substrate temperature can be controlled, thereby efficiently obtaining a high-quality printed object.

[0110] Example 5 Example 5 is an example of a method for selecting and cooling a portion of a molded object that needs to be cooled by applying Example 4. In Example 5, a rectangular shape as shown in FIG. 4 is molded, similar to Example 1.

[0111] Example 5 differs from Examples 3 and 4 in that the temperature of the entire object is measured in the temperature measurement process, and the parts of the object that are higher than a predetermined temperature are cooled. Depending on the shape of the object, the heat accumulation of the object is not uniform, and the parts that need to be cooled vary. For example, for a rectangular object, the parts from the start point A of the object are cooled. s , end point A f In addition, heat tends to accumulate at the 90-degree bend. Example 5 is an example in which the entire object is not cooled, but only the high-temperature areas that require cooling are cooled.

[0112] FIG. 14 is a schematic cross-sectional view showing a metal additive manufacturing apparatus 210 according to a fifth embodiment. In the fifth embodiment, a thermoviewer capable of measuring a wide area is used as the temperature measuring device 28. This makes it possible to measure the temperature of the entire object, rather than just a few locations. In the fifth embodiment, as shown in FIG. 14, the thermoviewer is provided separately from the processing head 12 and is installed so that the temperature of the entire object can be measured. Note that the thermoviewer may be integrated with the processing head 12, as long as it is installed in a location where it can measure the temperature of the entire object.

[0113] FIG. 15 is a flowchart showing the operation of a metal additive manufacturing apparatus 210 and a method for manufacturing a metal additive manufacturing object according to Example 5. In Example 5, as shown in the flowchart in FIG. 15, step S10 is followed by step S20, and then step S30. In step S30, the operations of the wire nozzle 14, the beam nozzle 13, the shielding gas nozzle 15, and the cooling nozzle 11 are stopped, and the temperature of the entire object is measured using a thermoviewer, which is a temperature measuring device 28. Note that, if the flow rate of the shielding gas 24 sprayed by the shielding gas nozzle 15 is a flow rate that does not affect the temperature measurement, the shielding gas nozzle 15 may spray the shielding gas 24 in step S30. Similarly, if the flow rate of the cooling medium 25 sprayed by the cooling nozzle 11 is a flow rate that does not affect the temperature measurement, the cooling nozzle 11 may spray the cooling medium 25 in step S30.

[0114] If the measurement result of the temperature gauge 28 in step S30 is equal to or lower than the predetermined temperature, step S10, which is the modeling process for the (N+1)th layer, is performed next. On the other hand, if the measurement result of the temperature gauge 28 in step S30 is higher than the predetermined temperature, step S40 is performed next. In step S40, cooling is performed only on the parts of the model that are found to have a temperature higher than the predetermined temperature from the measurement result of the temperature gauge 28 in step S30, i.e., the heat accumulation parts of the model. The cooling path R in step S40 c is the printing path R in step S10. a The cooling path R in step S40 is the same as or opposite to the cooling path R in step S40, and the cooling medium 25 is sprayed only onto the heat accumulation portion. c is the modeling path R a The direction does not have to be the same as or opposite to the above, and the heat accumulation point may be cooled via the shortest route. After step S40 is completed, step S30 is performed again, and depending on the result of the temperature measuring instrument 28, the process proceeds to step S10 or step S40.

[0115] As described above, in Example 5, the temperature measuring device 28 measures the temperature of the entire object, and instead of cooling the entire object, cooling is performed only on the high-temperature parts of the object that require cooling, thereby enabling the object to be cooled efficiently. Furthermore, even if the temperature and heat accumulation differ depending on the part of the object due to its complex shape, it is possible to cool only the parts of the object that require cooling, and also to appropriately manage the base temperature of the object.

[0116] Embodiment 3 Next, a description will be given of embodiment 3. Fig. 16 is a schematic cross-sectional view showing a metal additive manufacturing apparatus 300 according to example 6 of embodiment 3. Note that the same components as those in embodiments 1 and 2 are given the same reference numerals, and their description will be omitted.

[0117] As shown in FIG. 16, a metal additive manufacturing apparatus 300 according to the third embodiment differs from the first and second embodiments in that the cooling nozzle 11 and the shielding gas nozzle 15 are coaxial.

[0118] 16 , in a manufacturing apparatus 300 for a metal additive manufacturing object according to the third embodiment, a beam nozzle 13, a shield gas nozzle 15, and a cooling nozzle 11 are arranged coaxially and in a triple structure in a processing head 12. For example, the triple nozzle structure has the beam nozzle 13 at the center and the beam nozzle 13, the shield gas nozzle 15, and the cooling nozzle 11 arranged in this order from the center outward. The cooling nozzle 11, which is located on the outer periphery of the shield gas nozzle 15, can spray a cooling medium 25 toward a processing point 22. Note that the arrangement of the beam nozzle 13, the shield gas nozzle 15, and the cooling nozzle 11 is not limited to this.

[0119] In the metal additive manufacturing apparatus 300 of this embodiment, the shielding gas nozzle 15 is provided coaxially with the beam nozzle 13, and further, the cooling nozzle 11 is coaxial with the shielding gas nozzle 15, so that the cooling nozzle 11 is coaxial with the beam nozzle 13. Furthermore, as shown in Fig. 16, the spray direction of the cooling nozzle 11, which is provided coaxially with the beam nozzle 13, is the same as the direction in which the beam nozzle 13 emits the laser beam 23.

[0120] 1, for example, it is assumed that the cooling nozzle 11 is provided on the left side of the beam nozzle 13, and that the cooling nozzle 11 sprays the cooling medium 25 from the left side of the figure to the right side of the processing point 22. In this case, the cooling medium 25 may hit the left side of the object shown in FIG. 1 well and the right side of the object poorly, and the ease with which the cooling medium 25 hits may differ depending on the part of the object, resulting in a difference in the cooling effect.

[0121] 17, it is assumed that the direction in which the cooling nozzle 11 sprays the cooling medium 25 is perpendicular to the installation surface of the stage 17. In the metal additive manufacturing apparatus 300 of the third embodiment, the direction in which the cooling nozzle 11 sprays the cooling medium 25 is the same as the direction in which the beam nozzle 13 emits the laser beam 23, so that the cooling medium 25 is sprayed symmetrically to the processing point 22. This makes it possible to cool the object with little unevenness, resulting in a high-quality object.

[0122] In the metal additive manufacturing apparatus 300 according to the third embodiment, the cooling nozzle 11 is coaxial with the shielding gas nozzle 15. However, the cooling nozzle 11 may be the same as the shielding gas nozzle 15. FIG. 17 is a schematic cross-sectional view showing a manufacturing apparatus 310, which is a modification of the metal additive manufacturing apparatus 300 according to the third embodiment. As shown in FIG. 17, the metal additive manufacturing apparatus 310 according to the third embodiment is provided with a combined nozzle 29 in which the cooling nozzle 11 and the shielding gas nozzle 15 are combined. The metal additive manufacturing apparatus 310 may further include a mechanism connected to the combined nozzle 29 for switching the supplied gas between the shielding gas 24 and the cooling medium 25. In addition, the shielding gas 24 and the cooling medium 25 are sprayed, and although the shielding gas 24 and the cooling medium 25 are different from each other, the shielding gas 24 and the cooling medium 25 may be the same and used.

[0123] A specific example will be described below.

[0124] Example 6 Example 6 is an example of a manufacturing apparatus 300 in which the beam nozzle 13, the shielding gas nozzle 15, and the cooling nozzle 11 are configured coaxially. In Example 6, similar to Example 1, a rectangular shape as shown in FIG. 4 is manufactured. The manufacturing method and steps of the metal additive manufacturing object according to Example 6 were performed in the same order as in Example 1.

[0125] The configurations of the beam nozzle 13, shield gas nozzle 15, and cooling nozzle 11 of the metal additive manufacturing apparatus 300 according to Example 6 will be described. As shown in Fig. 16, the beam nozzle 13, shield gas nozzle 15, and cooling nozzle 11 are arranged coaxially and are provided in a triple structure in the processing head 12. This triple-structure nozzle is arranged with the beam nozzle 13 at the center, in the order of the beam nozzle 13, shield gas nozzle 15, and cooling nozzle 11 from the center outward. In Example 6, as in Example 1, the stage 17 is not moved, but the processing head 12 is moved to perform the manufacturing process and the cooling process.

[0126] In Example 6, similarly to Example 1, step S0 was followed by step S10, and then step S20, as shown in Fig. 6. Here, in step S20, the cooling nozzle 11 was provided coaxially with the beam nozzle 13 and the shielding gas nozzle 15, thereby further reducing unevenness in the spraying of the cooling medium 25 onto the molded object.

[0127] As described above, in Example 6, the cooling nozzle 11 is provided coaxially with the beam nozzle 13 and the shield gas nozzle 15, so that the object can be cooled to a desired temperature with less unevenness in cooling.

[0128] The configurations described in the above embodiments are merely examples of the contents of the present disclosure, and the techniques of the embodiments may be combined with each other or with other known techniques. Furthermore, it is also possible to omit or modify part of the configurations without departing from the gist of the present disclosure. [Explanation of symbols]

[0129] 1 control device, 2 laser oscillator, 3 fiber cable, 4 rotation motor, 5 wire, 6 wire spool, 7 shielding gas supply device, 8 shielding gas piping, 9 cooling medium supply device, 10 cooling medium piping, 11 cooling nozzle, 12 processing head, 13 beam nozzle, 14 wire nozzle, 15 shielding gas nozzle, 16 head drive device, 17 stage, 18 rotation device, 19 base material, 20 bead, 22 processing point, 23 laser beam, 24 shielding gas, 25 cooling medium, 28 temperature measuring device, 29 combined nozzle, 41 CPU, 42 RAM, 43 ROM, 44 external storage device, 45 input / output interface, 46 bus, 100, 200, 210, 300, 310 metal additive manufacturing device, A s Printing starting point, A f Build end point, C s Cooling start point, C f Cooling end point, R a Formative path, R c Cooling path, S10, S20, S30, S40 steps.

Claims

1. A method for manufacturing a metal additive manufacturing object by repeating a manufacturing process, a manufacturing process in which, while a shielding gas is sprayed from a shielding gas spraying unit, a heating unit that moves relatively to a stage on which a model is placed generates a heat source to heat a raw metal material supplied by a supply unit, and the heating unit deposits a bead of the melted raw metal material on the model, thereby manufacturing the model layer by layer; a cooling step, after the manufacturing step and before the next manufacturing step, of cooling the object manufactured in the manufacturing step by spraying a cooling medium from a cooling unit provided separately from the shielding gas spraying unit at a flow rate greater than a flow rate of the shielding gas while moving relatively to the stage; Equipped with the metal additive manufacturing object is formed by repeatedly depositing one layer of the object, which is the bead created in the manufacturing process, on the object; the modeling step includes: modeling the one-layer model that forms the metal additive manufacturing body by the heating unit heating the metal raw material along a first path on the model, which is a path from a modeling start position to a modeling end position; and stopping the spraying of the cooling medium from the cooling unit while the heating unit is heating; a cooling unit that sprays the cooling medium along a second path on the object, the second path being a path from a cooling start position to a cooling end position, to cool the single layer of the object formed in the forming step, the second path being in the same direction as or opposite to the first path, and the heating unit that stops heating while the cooling unit is cooling.

2. a temperature measurement step of stopping heating of the heating unit and measuring the temperature of the object by a temperature measuring device before the next modeling step; When the measurement result of the temperature measuring instrument is equal to or lower than a predetermined temperature, the molding process is performed; The method for manufacturing a metal additive manufacturing object according to claim 1 , wherein the cooling step is performed when the measurement result of the temperature measuring device is higher than a predetermined temperature.

3. The method for manufacturing a metal additive manufacturing object according to claim 2 , wherein the temperature measuring step measures the temperature of the shaped object at the shaping start position during the shaping step using the temperature measuring device.

4. The method for manufacturing a metal additive manufacturing object according to claim 2 , wherein the temperature measuring step measures the temperature of the entire object using the temperature measuring device.

5. 5. The method for manufacturing a metal additive manufacturing object according to claim 4, wherein, when the measurement result of the temperature measuring instrument is higher than a predetermined temperature, the cooling step cools the object by spraying the cooling medium from the cooling unit onto a portion of the object where the measurement result of the temperature measuring instrument is higher than the predetermined temperature.

6. 6. The method for manufacturing a metal additive manufacturing product according to claim 1, wherein the cooling medium is at least one of helium gas, argon gas, nitrogen gas, carbon dioxide gas, dry ice, and liquid nitrogen.

7. The flow rate of the shielding gas is a flow rate that results in a laminar flow, The method for manufacturing a metal additive manufacturing object according to any one of claims 1 to 5, wherein the flow rate of the cooling medium is a flow rate that causes turbulence.

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