Sintering lamination molding apparatus

Abstract

To provide a sintering lamination shaping apparatus capable of producing a three dimensional shaped article having improved mechanical properties.SOLUTION: The sintering lamination shaping apparatus (100) includes a reducing atmosphere generation device (20) connected to the shaping section (2) so as to be capable of gas exchange. The reducing atmosphere generation device (20) includes a heater (22) for heating the reducing material to a predetermined temperature, and generates the reducing atmosphere heated to the predetermined temperature by the heater (22). The predetermined temperature is set to a temperature at which the reducing material exhibits reducibility. The reducing atmosphere generated by the reducing atmosphere generation device (20) is supplied to the shaping part (2), and a three dimensional shaped article is produced in the reducing atmosphere heated to a predetermined temperature.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sintering layered manufacturing apparatus. [Background technology]

[0002] Sintering additive manufacturing devices, which create three-dimensional objects by irradiating a laser onto metal powder on the modeling stage, have been put into practical use. Sintering additive manufacturing devices are generally called "metal 3D printers."

[0003] A metal 3D printer has a stage installed in a chamber that constitutes the modeling unit, and metal powder supplied from a powder material supply unit to the modeling unit is irradiated with a laser on the stage, thereby forming a sintered layer.The stage is then sequentially lowered to stack the sintered layers, creating a three-dimensional object.

[0004] Patent Document 1 discloses a typical metal 3D printer. The metal 3D printer supplies nitrogen gas to a chamber that constitutes the modeling unit, and in the presence of nitrogen gas, creates a three-dimensional object while preventing oxidation of the metal powder. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-73752 Summary of the Invention [Problem to be solved by the invention]

[0006] The mechanical properties of three-dimensional objects produced by conventional metal 3D printers are sometimes insufficient. Therefore, an object of the present invention is to provide a sintering additive manufacturing device that can produce three-dimensional objects with improved mechanical properties. [Means for solving the problem]

[0007] Under the above technical problems, the present invention provides: A sintering and layered manufacturing apparatus that irradiates a laser onto a metal material supplied onto a stage of a manufacturing unit to form sintered layers, and then stacks the sintered layers to manufacture a three-dimensional object, a reducing atmosphere generating device connected to the molding unit so as to be able to exchange gas; the reducing atmosphere generating device includes a heater that heats the reducing material to a predetermined temperature; the reducing atmosphere generating device generates a reducing atmosphere heated to a predetermined temperature by the heater, the predetermined temperature is set to a temperature at which the reducing material exhibits reducing properties; The reducing atmosphere having the predetermined temperature generated by the reducing atmosphere generating device is supplied to the molding unit, The present invention provides a sintering layered manufacturing apparatus, characterized in that the manufacturing unit manufactures a three-dimensional object in a reducing atmosphere heated to the predetermined temperature. [Brief explanation of the drawings]

[0008] [Figure 1] Schematic diagram of the metal 3D printer in the example [Figure 2] A schematic diagram showing a first example in which the inside of the storage tank is made into a reducing atmosphere by using a reducing material, and the metal powder is forcibly stirred by a stirring member. [Figure 3] A schematic diagram showing a second example of forced stirring of metal powder in a storage tank using a rotary table under a reducing atmosphere. [Figure 4] A schematic diagram showing a third example of forced stirring of metal powder in a storage tank using a vibrating plate under a reducing atmosphere. [Example]

[0009] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram of a sintering additive manufacturing apparatus, i.e., a metal 3D printer, according to an embodiment. The metal 3D printer 100 has a chamber 2 that constitutes the manufacturing section and a stage 4 located at the bottom of the chamber 2, with the stage 4 being driven up and down by an elevator mechanism 6. The metal 3D printer 100 also has a laser irradiation source 8. The laser emitted by the laser irradiation source 8 is directed toward the stage 4. Although not shown, a reflector is located between the laser irradiation source 8 and the stage 4, and the angle of this reflector is controlled by a control unit (not shown) according to input data, as in conventional systems. The control unit also controls the elevation of the stage 4.

[0010] The metal 3D printer 100 has a powder material supply unit 10. The powder material supply unit 10 has a storage tank 12 that stores metal powder, and a powder material supply device 14 that supplies the metal powder from the storage tank 12 to the chamber 2. The powder material supply device 14 is controlled according to input data. The powder material supply device 14 supplies a controlled amount of metal powder to the chamber (modeling unit) 2 through a nozzle 16.

[0011] A roller (not shown) is installed in chamber 2. Metal powder supplied to chamber 2 through nozzle 16 is formed to a uniform thickness by the roller on stage 4. Next, a laser is irradiated onto the metal powder on stage 4 in accordance with input data. This forms a sintered layer. Any excess metal powder is then collected in recovery tank 18. Thereafter, stage 4 is moved downward in sequence, and the above process is repeated repeatedly. This produces a three-dimensional object of the desired shape by stacking sintered layers.

[0012] The metal 3D printer 100 has a first reducing atmosphere generating device 20, which is equipped with a first heater 22. A reducing material is supplied to the first reducing atmosphere generating device 20 from a first reducing material source 24. The reducing material is preferably formic acid, hydrogen gas, or carbon monoxide gas. The first heater 22 heats the inside of the first reducing atmosphere generating device 20 to a predetermined temperature. This temperature is set to a temperature at which formic acid, hydrogen gas, or carbon monoxide gas exerts a reducing effect. For example, in the case of formic acid, the reducing effect occurs at 120°C to 200°C. For example, in the case of carbon monoxide, the reducing effect occurs at approximately 900°C.

[0013] When for example formic acid is supplied to the first reducing atmosphere generating device 20 from the first reducing material source 24, the first heater 22 generates a high-temperature (120°C to 200°C) reducing atmosphere in which the formic acid exerts a reducing effect.

[0014] The first reducing atmosphere generating device 20 is connected to the chamber 2 so as to enable gas exchange. The high-temperature reducing atmosphere generated by the first reducing atmosphere generating device 20 is supplied to the chamber 2, and the internal space of the chamber 2 is filled with this high-temperature reducing atmosphere. Then, in this high-temperature reducing atmosphere, a three-dimensional object having a desired shape is produced by stacking sintered layers.

[0015] It is preferable to remove an oxide film from the metal powder before supplying the metal powder to chamber 2. Referring to Figure 1, the metal 3D printer 100 has a second reducing atmosphere generating device 30, which is equipped with a second heater 32. A reducible material is supplied to the second reducing atmosphere generating device 30 from a second reducible material source 34. The reducible material is preferably any one of formic acid, hydrogen gas, and carbon monoxide gas.

[0016] When for example formic acid is supplied to the first reducing atmosphere generating device 20 from the second reducing material source 34, the second heater 32 generates a high-temperature (120°C to 200°C) reducing atmosphere in which the formic acid exerts a reducing effect.

[0017] The second reducing atmosphere generator 30 is connected to the powder material supply unit 10 so as to be able to exchange gases. The high-temperature reducing atmosphere generated by the second reducing atmosphere generator 30 is supplied to the powder material supply unit 10. In the powder material supply unit 10, before the metal powder is supplied to the chamber 2, the oxide film on the metal powder is removed by the high-temperature reducing atmosphere.

[0018] The high-temperature reducing atmosphere generated by the second reducing atmosphere generating device 30 may be supplied to either the storage tank 12 or the powder material supply device 14, or to both the storage tank 12 and the powder material supply device 14.

[0019] 2 to 4 show examples in which a high-temperature reducing atmosphere is supplied to the storage tank 12. In the first example shown in FIG. 2, the storage tank 12 has a stirring member 40. The metal powder Pw contained in the storage tank 12 is forcibly stirred by the stirring member 40 under the high-temperature reducing atmosphere. By forcibly stirring the metal powder Pw, it is possible to increase the reliability of oxide film removal.

[0020] 3 shows a second example in which the storage tank 12 is provided with a rotary table 42 at its bottom. The rotary table 42 can be driven by an electric motor 44 to forcibly stir the metal powder Pw. Preferably, the rotary table 42 has a plurality of fins 46 on its upper surface.

[0021] 3 shows a configuration in which the rotary table 42 rotates about an axis on a horizontal plane. As a modification, the axis 42a of the rotary table 42 may be inclined from the vertical axis, so that the rotary table 42 is disposed at an angle from the horizontal plane.

[0022] 4 shows a third example in which a vibrating plate 50 is provided at the bottom of the storage tank 12. The metal powder Pw can be forcibly stirred by vibrating the vibrating plate 50 with a vibration source 52. Although not shown in the figure, the rotary table 42 shown in the third example (FIG. 3) may also be vibrated.

[0023] Metal 3D printers are known that use filament- or rod-shaped metal materials to create three-dimensional objects of desired shapes. The present invention can also be suitably applied to these types of metal 3D printers. [Explanation of symbols]

[0024] 100 Example of metal 3D printer 2. Chamber (modeling section) 4 Stages 8 Laser irradiation source 10 Powder material supply section 12 Storage Tank 14 Powder material feeding device 20 First reducing atmosphere generator (for chamber) 22 First heater 24 First source of reducible materials Pw metal powder

Claims

1. A sintering and layered manufacturing apparatus that irradiates a laser onto a metal material supplied onto a stage of a manufacturing unit to form sintered layers, and then stacks the sintered layers to manufacture a three-dimensional object, a reducing atmosphere generating device connected to the molding unit so as to be able to exchange gas; the reducing atmosphere generating device includes a heater that heats the reducing material to a predetermined temperature; the reducing atmosphere generating device generates a reducing atmosphere heated to a predetermined temperature by the heater, the predetermined temperature is set to a temperature at which the reducing material exhibits reducing properties; The reducing atmosphere having the predetermined temperature generated by the reducing atmosphere generating device is supplied to the molding unit, A sintering and layered manufacturing apparatus, characterized in that the manufacturing unit manufactures a three-dimensional object in a reducing atmosphere heated to the predetermined temperature.

2. The sintering layered manufacturing apparatus according to claim 1, The sintering additive manufacturing apparatus, wherein the reducing material is formic acid, hydrogen gas, or carbon monoxide gas.

3. The sintering layered manufacturing apparatus according to claim 1 or 2, The sintering additive manufacturing apparatus, wherein the metal material is a powdered metal.

4. The sintering layered manufacturing apparatus according to claim 1 or 2, A sintering additive manufacturing apparatus, wherein the metal material is a filament-like metal.

5. The sintering layered manufacturing apparatus according to claim 1 or 2, The sintering additive manufacturing apparatus, wherein the metal material is a rod-shaped metal.

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