Three-dimensional shaping device and method for manufacturing three-dimensional object

Abstract

To obtain a three-dimensional shaping device capable of suppressing a smoke phenomenon without performing temporary sintering by irradiation with a preheating electron beam to a powder layer spread on the upper surface of a base plate.SOLUTION: A three-dimensional shaping device 100 includes an electron gun 11 for emitting an electron beam 11a, a powder bed wall 12 for surrounding a shaping area 2 where shaping is performed, powder feeding means 13 for feeding powder 3 to the shaping area 2, and an electrode device 4 for generating an electric field around the shaping area 2. The electrode device 4 is formed with a plurality of slit-like openings for passing the electron beam 11a. The electrode device 4 includes an electrode 5 arranged at a position directly above the shaping area 2, a power supply 6 for providing a potential difference between the electrode 5 and the shaping area 2, and a moving mechanism 7 for moving the electrode 5 to a target position. The electrode 5 is positioned directly above the shaping area 2 by the moving mechanism 7, and when a voltage is applied to the electrode 5 by the power supply 6, an electric field is generated around the shaping area 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a three-dimensional modeling apparatus and a method for manufacturing a three-dimensional object. [Background technology]

[0002] Conventionally, there is known a three-dimensional modeling apparatus that irradiates an electron beam onto metal powder spread in a modeling area to melt and solidify the powder to form a three-dimensional model. In such a three-dimensional modeling apparatus, a first powder layer is formed on the upper surface of a base plate installed in the modeling area, and then an electron beam is irradiated thereon. A next powder layer is formed on top of the powder layer irradiated with the electron beam, and then an electron beam is irradiated thereon. The three-dimensional modeling apparatus repeatedly forms powder layers and irradiates the electron beam, thereby stacking the layers that make up the model one by one to form the model.

[0003] It is known that three-dimensional modeling devices can suffer from a phenomenon known as "smoking," in which powder particles become negatively charged during modeling and repel each other, causing the powder to scatter. The occurrence of this phenomenon can result in an incomplete powder layer, potentially resulting in defective modeling. Therefore, in three-dimensional modeling devices, a preheating electron beam is directly irradiated onto the powder layer to perform pre-sintering before irradiating it with the electron beam for modeling, thereby preventing the powder from becoming charged when the electron beam for modeling is irradiated. For example, Patent Document 1 discloses a three-dimensional additive manufacturing device equipped with a charge shield that covers unsintered areas of powder dispersed on the modeling surface that are not irradiated with the electron beam. The charge shield has an opening that allows the electron beam from the electron gun to pass through. In this three-dimensional additive manufacturing device, a preheating electron beam is irradiated onto the powder through the opening in the charge shield, causing the powder in the irradiated area to be pre-sintered. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6216464 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technique disclosed in Patent Document 1 requires heating the powder layer to a temperature required for pre-sintering, and the heating time increases the molding time, which may reduce productivity.

[0006] The present disclosure has been made in consideration of the above, and aims to provide a three-dimensional modeling device that can suppress the smoke phenomenon without pre-sintering a powder layer spread on the upper surface of a base plate by irradiating it with a preheating electron beam. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the present disclosure provides a three-dimensional modeling apparatus that irradiates an electron beam onto powder spread in a modeling area to melt and solidify the powder to form a three-dimensional model, and includes an electron gun that emits the electron beam, a powder bed wall that surrounds the modeling area where modeling by electron beam irradiation is performed, a powder supplying means that supplies powder to the modeling area, and an electrode device that generates an electric field around the modeling area. The electrode device is formed with a plurality of slit-shaped openings that allow the electron beam emitted from the electron gun to pass through, and includes an electrode that is located directly above the modeling area, a power supply that applies a potential difference between the electrode and the modeling area, and a movement mechanism that moves the electrode to a target position, where the electrode is located directly above the modeling area by the movement mechanism, and a voltage is applied to the electrode by the power supply, thereby generating an electric field around the modeling area. [Effects of the Invention]

[0008] The three-dimensional modeling apparatus according to the present disclosure has the advantage of being able to suppress the smoke phenomenon without requiring preliminary sintering by irradiating a powder layer spread on the upper surface of a base plate with an electron beam for preheating. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram illustrating an overall configuration of a three-dimensional modeling apparatus according to an embodiment of the present invention; [Figure 2] An explanatory diagram showing the smoke phenomenon that occurs when powder is irradiated with an electron beam. [Figure 3] FIG. 1 is a plan view schematically showing an electrode device included in a three-dimensional modeling apparatus according to an embodiment; [Figure 4] FIG. 1 is a cross-sectional view schematically illustrating an internal structure of an electrode included in a three-dimensional modeling apparatus according to an embodiment; [Figure 5] FIG. 10 is an explanatory diagram illustrating how an electric field is generated around a modeling area by an electrode device included in the three-dimensional modeling apparatus according to the embodiment. [Figure 6] FIG. 1 is an explanatory diagram illustrating a state in which an electrode included in the three-dimensional modeling apparatus according to the embodiment is placed at a modeling position A. [Figure 7] FIG. 10 is an explanatory diagram illustrating a state in which the electrodes of the three-dimensional modeling apparatus according to the embodiment are arranged at a modeling position B. [Figure 8] FIG. 10 is an explanatory diagram illustrating a modified example of a movement mechanism included in the three-dimensional modeling apparatus according to the embodiment; [Figure 9] IX-IX cross section shown in Figure 8 [Figure 10] 1 is a flowchart showing the steps of a method for manufacturing a three-dimensional object according to an embodiment. [Figure 11] 10 is a flowchart showing a first modification of the procedure of the method for manufacturing a three-dimensional object according to the embodiment; [Figure 12] 10 is a flowchart showing a second modified example of the procedure of the method for manufacturing a three-dimensional object according to the embodiment; [Figure 13] 10 is a flowchart showing a third modified example of the procedure of the method for manufacturing a three-dimensional object according to the embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a three-dimensional modeling apparatus and a method for manufacturing a three-dimensional object according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0011] Embodiment Fig. 1 is a schematic diagram of an overall configuration of a three-dimensional modeling apparatus according to an embodiment. As shown in Fig. 1, the three-dimensional modeling apparatus 100 according to the embodiment is an apparatus that irradiates an electron beam 11a onto powder 3 spread in a modeling area 2, melts and solidifies the powder 3, and manufactures a three-dimensional model 1.

[0012] The three-dimensional modeling apparatus 100 according to this embodiment includes a sealed chamber 10, an electron gun 11 that emits an electron beam 11a, a powder bed wall 12 that surrounds a modeling area 2 where modeling is performed by irradiating the electron beam 11a, and a powder supply means 13 that supplies powder 3 to the modeling area 2. A vacuum pump (not shown) that serves as an exhaust device is connected to the chamber 10. The interior of the chamber 10 is evacuated by the vacuum pump to create a vacuum or near-vacuum state. The powder bed wall 12 and the powder supply means 13 are provided inside the chamber 10.

[0013] The electron gun 11 is installed in an electron gun chamber 14 provided vertically above the chamber 10. The electron gun 11 has a mechanism for emitting electrons, a mechanism for converging the emitted electrons, and a mechanism for deflecting the electrons so that the electrons are irradiated at a specified position. The electron gun 11 adjusts the direction in which the electron beam 11a is deflected, thereby adjusting the irradiation position of the electron beam 11a.

[0014] The powder bed wall 12 has a cylindrical shape extending in the vertical direction. A lifting stage 15 that moves in the vertical direction is provided inside the cylindrical powder bed wall 12. The outer peripheral surface of the lifting stage 15 contacts the inner wall of the powder bed wall 12. The lifting stage 15 moves up and down while maintaining contact between the outer peripheral surface of the lifting stage 15 and the inner wall of the powder bed wall 12. The area surrounded by the cylindrical interior of the powder bed wall 12 and the lifting stage 15 forms the shaping area 2 where shaping by irradiating the electron beam 11a is performed. The upper end of the shaping area 2 coincides with the upper end of the powder bed wall 12. Note that a sealing member may be provided on the outer peripheral surface of the lifting stage 15. In this case, the lifting stage 15 moves up and down while maintaining contact between the sealing member and the inner wall of the powder bed wall 12. A platform portion 12a extending horizontally outside the shaping area 2 is formed at the upper end of the powder bed wall 12.

[0015] A base plate 16 serving as a base for the object 1 is provided on the upper surface of the lifting stage 15. The base plate 16 is, for example, a rectangular flat plate. However, the shape of the base plate 16 is not limited to rectangular and may be circular, for example. The base plate 16 is placed on the upper surface of the lifting stage 15 by an operator when the formation of the object 1 begins. After the formation of the object 1 is completed, the base plate 16 is removed together with the object 1. Although not shown in the drawings, the base plate 16 may be supported in a parallel state by being placed on a plurality of supports erected on the upper surface of the lifting stage 15.

[0016] The powder supplying means 13 includes a powder box 13a that stores the powder 3 and a recoater 13b that spreads the powder 3 evenly. When the powder 3 is discharged from the powder box 13a, the recoater 13b moves horizontally from above the platform 12a, through the modeling area 2, and to the platform 12a beyond the modeling area 2. In this way, the recoater 13b spreads the powder 3 evenly in the modeling area 2. In this way, the recoater 13b moves horizontally from outside the modeling area 2 into the modeling area 2 to supply the powder 3 into the modeling area 2, and then spreads the powder 3 inside the modeling area 2 to form a powder layer in the modeling area 2. Note that the recoater 13b may have any configuration as long as it is capable of spreading the powder 3 evenly.

[0017] The powder 3 used in the embodiment is, for example, titanium (Ti), a titanium alloy such as Ti-6Al-4V, copper (Cu), a copper alloy, or stainless steel. The powder 3 may also be aluminum (Al), an aluminum alloy such as AlSi10Mg, a titanium-aluminum alloy, a tantalum (Ta) alloy, Inconel (registered trademark), Invar (registered trademark), Super Invar, a cobalt-chromium (CoCr) alloy, Hastelloy (registered trademark), chromium-molybdenum (CrMo) steel, a tungsten (W) alloy, or a CoCrFeMnNi high-entropy alloy. The powder 3 used in the embodiment may be a metal other than the metals exemplified here.

[0018] The three-dimensional modeling apparatus 100 also has a control device 17 that controls the entire three-dimensional modeling apparatus 100. The control device 17 controls the electron gun 11 by outputting a control signal to the electron gun 11. The electron gun 11 controls the emission and stop of the electron beam 11a and the energy of the electron beam 11a in accordance with the control signal. The electron gun 11 adjusts the height position at which the electron beam 11a is converged in accordance with the control signal.

[0019] Furthermore, the electron gun 11 adjusts the irradiation position of the electron beam 11a in accordance with the control signal. For example, CAD (Computer-Aided Design) data, which is design data for the object 1, is input to the control device 17. The control device 17 generates two-dimensional slice data based on the CAD data. The slice data represents the cross-sectional shape of the object 1 for each layer stacked in the height direction. The control device 17 determines the irradiation position of the electron beam 11a based on the slice data, and outputs a control signal including an instruction for the irradiation position.

[0020] Furthermore, the control device 17 controls the recoater 13b by outputting a control signal to the recoater 13b. The recoater 13b moves horizontally in accordance with the control signal. The control device 17 controls the lift stage 15 by outputting a control signal to the lift stage 15. The lift stage 15 moves vertically in accordance with the control signal. The control device 17 adjusts the height position of the base plate 16 by controlling the lift stage 15.

[0021] The three-dimensional modeling apparatus 100 configured as described above forms a first powder layer on the upper surface of the base plate 16 and irradiates the first powder layer with the electron beam 11a. The three-dimensional modeling apparatus 100 forms a next powder layer on the powder layer irradiated with the electron beam 11a and irradiates the next powder layer with the electron beam 11a. The three-dimensional modeling apparatus 100 repeats the formation of powder layers and the irradiation of the electron beam 11a, thereby stacking the layers that make up the model 1 one by one, thereby forming the model 1.

[0022] FIG. 2 is an explanatory diagram illustrating the smoke phenomenon that occurs when powder is irradiated with an electron beam. As shown in FIG. 2, in a three-dimensional printing apparatus 100, when metal powder 3 is irradiated with an electron beam 11a and becomes charged, the particles of the powder 3 repel each other due to repulsive forces, causing the powder 3 to scatter, resulting in the so-called smoke phenomenon. For this reason, a known method for the three-dimensional printing apparatus 100 involves irradiating the powder 3 with a preheating electron beam 11a to perform pre-sintering before irradiating the powder 3 with the electron beam 11a for fabrication, thereby suppressing charging of the powder 3 when irradiated with the electron beam 11a for fabrication. However, the powder 3 must be heated to a temperature required for pre-sintering, and this heating time increases the fabrication time, potentially reducing productivity. Furthermore, if the pre-sintered powder 3 is to be crushed and reused, the process of crushing the powder 3 takes time.

[0023] 1, the three-dimensional printing apparatus 100 according to this embodiment includes, in addition to the above configuration, an electrode device 4 that generates an electric field E around the printing area 2. The electrode device 4 includes an electrode 5, a power source 6, and a movement mechanism 7. The electrode 5 and the movement mechanism 7 are provided inside a chamber 10.

[0024] FIG. 3 is a plan view schematically illustrating an electrode device included in a three-dimensional printing apparatus according to an embodiment. The electrode 5 is made of a material such as aluminum (Al) or tungsten (W). As shown in FIG. 3, the electrode 5 has a rectangular flat plate shape and is formed with a plurality of slit-shaped openings 50 arranged side by side to allow the electron beam 11a emitted from the electron gun 11 to pass therethrough. The electrode 5 has a ladder-like shape due to the plurality of openings 50. The openings 50 are formed at equal intervals between a pair of opposing edges of the rectangular outer periphery. The plurality of openings 50 are of the same shape and size, and are rectangular. For example, the width t1 of the opening 50 in the lateral direction and the width t2 of the electrode 5 sandwiched between adjacent openings 50 are approximately the same. The electrode 5 is disposed directly above the printing area 2 and covers the entire surface of the printing area 2. The electrode 5 is not limited to the rectangular shape shown in the figure and may have other shapes, such as a circular shape or an oval shape. Furthermore, the slit-shaped openings 50 are not limited to a rectangular shape, and may be other shapes such as an oval shape, etc. Furthermore, the slit-shaped openings 50 are not limited to a configuration in which they are formed at equal intervals between a pair of opposing edges, and may be formed radially from the center of the electrode 5, or may be other shapes.

[0025] FIG. 4 is a cross-sectional view schematically illustrating the internal structure of an electrode included in a three-dimensional modeling apparatus according to an embodiment. As shown in FIG. 4, a cooling channel 51 through which a cooling medium flows is formed inside the electrode 5. The cooling channel 51 is formed so that the cooling medium is distributed over the entire surface of the electrode 5. The cooling channel 51 is connected to a cooling device (not shown) that supplies the cooling medium. The electrode 5 is also provided with a temperature sensor (not shown) that detects the temperature of the electrode 5. The control device 17 controls the cooling device by outputting a control signal to the cooling device based on the temperature sensor. When the temperature of the electrode 5 exceeds a predetermined temperature, the cooling device supplies the cooling medium to the cooling channel 51 in accordance with the control signal to cool the electrode 5. The cooling device may also be configured to supply the cooling medium to the cooling channel 51 in accordance with the control signal to cool the electrode 5, regardless of the temperature of the electrode 5. The cooling channel 51 does not necessarily need to be formed so as to distribute over the entire surface of the electrode 5; it may be formed only in a portion of the electrode 5. The three-dimensional modeling apparatus 100 supplies a cooling medium to the cooling flow path 51 to cool the electrode 5, thereby preventing the electrode 5 from being damaged when heated by the electron beam 11a.

[0026] FIG. 5 is an explanatory diagram showing how an electric field is generated around the shaping area by an electrode device included in a three-dimensional modeling apparatus according to an embodiment. A power supply 6 is connected to the electrode 5 and a powder bed wall 12. As shown in FIG. 5, the power supply 6 applies a voltage to the electrode 5, creating a potential difference between the electrode 5 and the model 1. This generates an electric field E around the shaping area 2, and when the powder 3 becomes negatively charged, an electrostatic force F acts by the electric field E, pressing the powder 3 toward the model 1. The gravity and electrostatic force F acting on the powder 3 become greater than the repulsive force, thereby preventing the powder 3 from scattering.

[0027] As shown in FIG. 3 , the movement mechanism 7 includes a first movement mechanism 70 that moves the electrode 5 to a position directly above the fabrication area 2, and a second movement mechanism 71 that moves the electrode 5 along the direction in which the openings 50 are arranged. The first movement mechanism 70 and the second movement mechanism 71 are controlled by the control device 17. The first movement mechanism 70 is fixed to, for example, the chamber 10. The first movement mechanism 70 moves the electrode 5 vertically between the electron gun 11 and the fabrication area 2. The first movement mechanism 70 includes, for example, a ball screw 70a, a mount 70b, and a linear guide 70c. The ball screw 70a converts the rotation of a motor (not shown) into vertical movement. The mount 70b supports the electrode 5 and moves vertically due to the rotation of the ball screw 70a. The linear guide 70c slidably guides the movement of the mount 70b. After the powder 3 is spread in the modeling area 2 to form a powder layer, the first moving mechanism 70 moves the electrode 5 to a position directly above the modeling area 2, as shown by the solid line in FIG. 1. After modeling, the first moving mechanism 70 raises the electrode 5 from directly above the modeling area 2, as shown by the dashed line in FIG. 1. Note that the first moving mechanism 70 is not limited to the configuration shown in the figure, and may have another configuration as long as it can move the electrode 5 to a position directly above the modeling area 2.

[0028] Fig. 6 is an explanatory diagram showing a state in which an electrode of the three-dimensional printing apparatus according to the embodiment is arranged at a printing position A. Fig. 7 is an explanatory diagram showing a state in which an electrode of the three-dimensional printing apparatus according to the embodiment is arranged at a printing position B. The arrows shown in Figs. 6 and 7 indicate the scanning direction of the electron beam 11a.

[0029] The second movement mechanism 71 is configured, for example, with a ball screw and is driven by the rotation of a motor (not shown). The second movement mechanism 71 moves the electrode 5, which has been moved by the first movement mechanism 70 to a position directly above the printing area 2, along the direction in which the openings 50 are arranged. Specifically, the second movement mechanism 71 moves the electrode 5 from the printing position A shown in FIG. 6 to the printing position B shown in FIG. 7 so that the electron beam 11a can be irradiated onto the powder 3 through the openings 50 of the electrode 5. As a result, the 3D printing apparatus 100 first scans the electron beam 11a across each opening 50 of the electrode 5 arranged at the printing position A shown in FIG. 6, and then irradiates the powder 3 with the electron beam 11a to print the powder. Next, after printing at the printing position A shown in FIG. 6 is completed, the 3D printing apparatus 100 moves the electrode 5 from the printing position A to the printing position B shown in FIG. 7 by the second movement mechanism 71. 7, the electron beam 11a is scanned across each opening 50 of the electrode 5 placed at the manufacturing position B, and the powder 3 is irradiated with the electron beam 11a to manufacture the powder. That is, by using the second movement mechanism 71 to move the electrode 5 and shift the position of the opening 50, the powder 3 at the target manufacturing position can be irradiated with the electron beam 11a. Note that the second movement mechanism 71 is not limited to the configuration shown in the figure, and may have any other configuration as long as it can move along the direction in which the openings 50 are arranged.

[0030] FIG. 8 is an explanatory diagram illustrating a modified example of the movement mechanism of the three-dimensional modeling apparatus according to the embodiment. FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. 8. The first movement mechanism 70 of the movement mechanism 7 illustrated in FIGS. 8 and 9 includes a hinge mechanism that rotates the electrode 5 and moves it to a position directly above the modeling area 2. The electrode 5 is connected to the rotation axis of the hinge mechanism. After the powder 3 is spread in the modeling area 2 to form a powder layer, the first movement mechanism 70 rotates the electrode 5, which is standing upright facing the inner surface of the chamber 10 as indicated by the dashed line, to move the electrode 5 to a position directly above the modeling area 2 as indicated by the solid line. After modeling, the first movement mechanism 70 rotates the electrode 5, which is located directly above the modeling area 2, to a position directly above the modeling area 2 so that the electrode 5 is standing upright facing the inner surface of the chamber 10. The first movement mechanism 70 is controlled by the control device 17. Although not shown, the moving mechanism 7 shown in FIGS. 8 and 9 also has a second moving mechanism section 71 having the same configuration as above.

[0031] Next, a procedure for manufacturing the three-dimensional object 1 by the manufacturing method of the three-dimensional object according to this embodiment will be described. Fig. 10 is a flowchart showing the procedure of the manufacturing method of the three-dimensional object according to this embodiment. The manufacturing method of the three-dimensional object according to this embodiment is performed using the three-dimensional printing apparatus 100 configured as described above.

[0032] First, the 3D modeling apparatus 100 adjusts the height of the base plate 16 installed on the upper surface of the lift stage 15, and then irradiates the base plate 16 with the electron beam 11a to heat it (step S101). The lift stage 15 moves vertically, positioning the base plate 16 at a position lower than the top end of the powder bed wall 12 by the thickness of the powder layer. Furthermore, by heating the base plate 16, the powder layer formed on the upper surface of the base plate 16 can be pre-sintered. Note that in conventional techniques, the base plate 16 had to be heated to a high temperature to transfer the residual heat from the heated base plate 16 to the upper layers of the sequentially stacked powder layers. In contrast, in the present embodiment, an electric field E is generated around the shaping area 2, as described below, so the base plate 16 does not need to be heated to a high temperature as in conventional techniques, contributing to a reduction in shaping time. Note that the base plate 16 may be heated before adjusting its height.

[0033] Next, the three-dimensional modeling apparatus 100 forms one powder layer in the modeling area 2 where the base plate 16 supported by the lifting stage 15 is placed (step S102). The powder layer is formed by spreading the powder 3 in the modeling area 2 as the recoater 13b moves from outside the modeling area 2 into the modeling area 2.

[0034] Next, after forming the first powder layer, the 3D modeling apparatus 100 uses the first movement mechanism 70 to lower the electrode 5 to a position directly above the modeling area 2 (step S103). At this time, the electrode 5 is placed at modeling position A shown in FIG. 6 and covers the entire surface of the modeling area 2. Then, the 3D modeling apparatus 100 applies a voltage to the electrode 5 using the power supply 6, thereby creating a potential difference between the electrode 5 and the base plate 16 and generating an electric field E around the modeling area 2 (step S104). The generation of the electric field E around the modeling area 2 attracts the powder 3 to the modeling area 2 by electrostatic force F.

[0035] Next, the 3D printing apparatus 100 irradiates the powder 3 with the electron beam 11a from the electron gun 11 to print the first layer. First, as shown in FIG. 6, the 3D printing apparatus 100 scans each opening 50 of the electrode 5 arranged at the printing position A with the electron beam 11a, and irradiates the powder 3 with the electron beam 11a to print (step S105). The electron gun 11 adjusts the irradiation position in accordance with a control signal. Next, the 3D printing apparatus 100 moves the electrode 5 from the printing position A shown in FIG. 6 to the printing position B shown in FIG. 7 by the second movement mechanism 71 (step S106). Next, as shown in FIG. 7, the 3D printing apparatus 100 scans each opening 50 of the electrode 5 arranged at the printing position B with the electron beam 11a, and irradiates the powder 3 with the electron beam 11a to print (step S107). The electron gun 11 adjusts the irradiation position in accordance with a control signal. In this embodiment, an electric field E is generated around the fabrication area 2, and the powder 3 is attracted to the fabrication area 2 by an electrostatic force F. This makes it possible to suppress the smoke phenomenon caused by the powder 3 becoming negatively charged during fabrication.

[0036] Next, the 3D printing device 100 determines whether or not the formation of the object 1 is complete (step S108). If the formation of the first layer is complete but the formation of the second and subsequent layers is not complete, the 3D printing device 100 determines that the formation of the object 1 is not complete (step S108: No). In this case, the 3D printing device 100 raises the electrode 5 by the first movement mechanism 70 (step S109), lowers the lifting stage 15 by the thickness of the next powder layer to adjust the height of the base plate 16, and then returns the procedure to step S102, thereby forming the second and subsequent powder layers.

[0037] The procedure from step S102 to step S109 is repeated until the formation of all layers of the object 1 is completed. When the formation of all layers of the object 1 is completed, the 3D printing apparatus 100 determines that the formation of the object 1 is completed (step S108: Yes). The 3D printing apparatus 100 supplies a cooling medium from a cooling device (not shown) to the cooling flow path 51 to cool the electrode 5 (step S110). The 3D printing apparatus 100 lowers the electrode 5 using the first movement mechanism 70, brings the cooled electrode 5 into contact with the upper surface of the printing area 2, and cools the object 1 (step S111). This allows the object 1 to be cooled quickly, which contributes to shortening the printing time. Note that the processes of step S110 and step S111 are not necessarily required and may be omitted. Finally, the three-dimensional modeling apparatus 100 causes the first movement mechanism 70 to raise the electrode 5 (step S112), and the production of the model 1 is completed.

[0038] As described above, the three-dimensional modeling apparatus 100 according to the embodiment includes an electron gun 11 that emits an electron beam 11a, a powder bed wall 12 that surrounds the modeling area 2 where modeling is performed by irradiating the electron beam 11a, a powder supplying means 13 that supplies powder 3 to the modeling area 2, and an electrode device 4 that generates an electric field E around the modeling area 2. The electrode device 4 includes an electrode 5 that is formed with a plurality of slit-shaped openings 50 that allow the electron beam 11a emitted from the electron gun 11 to pass through, and is positioned directly above the modeling area 2, a power supply 6 that applies a potential difference between the electrode 5 and the modeling area 2, and a movement mechanism 7 that moves the electrode 5 to a target position. The electrode device 4 generates an electric field E around the modeling area 2 by positioning the electrode 5 directly above the modeling area 2 using the movement mechanism 7 and applying a voltage to the electrode 5 using the power supply 6. In other words, the three-dimensional printing apparatus 100 according to this embodiment generates an electric field E around the printing area 2, which attracts the powder 3 to the printing area 2 by electrostatic force F, thereby suppressing the smoke phenomenon without pre-sintering the powder layer spread on the upper surface of the base plate 16 by irradiating it with a preheating electron beam 11a.

[0039] Next, Modifications 1 to 3 of the procedure for manufacturing a three-dimensional object 1 by the method for manufacturing a three-dimensional object according to the present embodiment will be described with reference to Fig. 11 to Fig. 13. Fig. 11 is a flowchart showing Modification 1 of the procedure for manufacturing a three-dimensional object according to the embodiment. Note that steps S201 to S204 are similar to steps S101 to S104 shown in Fig. 10, and therefore their description will be omitted.

[0040] In step S204, the 3D printing apparatus 100 generates an electric field E around the printing area 2. Then, the electrode 5 is irradiated with the electron beam 11a from the electron gun 11 to heat the electrode 5 (step S205), and the powder 3 is heated by radiant heat from the electrode 5. This allows the powder 3 to be pre-sintered. Note that in this embodiment, an electric field E is generated around the printing area 2. Therefore, the temperature at which the powder 3 is heated can be lower than when the powder 3 is heated by directly irradiating the electron beam 11a to the powder 3, as in the prior art. Also, in this embodiment, the electrode 5 is arranged to cover the entire surface of the printing area 2, so the powder 3 in the printing area 2 can be heated almost uniformly. This allows the powder 3 to be pre-sintered at an appropriate temperature across the entire surface of the printing area 2. Note that if the pre-sintering is not uniform, there is a risk that some areas of the powder 3 will be overheated or insufficiently heated. If the powder 3 is overheated, it will take a long time to break down the pre-sintered powder 3 and reuse it. Furthermore, if the powder 3 is not heated sufficiently, there is a risk of smoke occurring.

[0041] Next, the 3D printing apparatus 100 irradiates the powder 3 with the electron beam 11a from the electron gun 11 to print the first layer. First, as shown in FIG. 6, the 3D printing apparatus 100 scans each opening 50 of the electrode 5 arranged at the printing position A with the electron beam 11a, and irradiates the powder 3 with the electron beam 11a to print (step S206). The electron gun 11 adjusts the irradiation position in accordance with a control signal. Next, the 3D printing apparatus 100 moves the electrode 5 from the printing position A shown in FIG. 6 to the printing position B shown in FIG. 7 by the second movement mechanism 71 (step S207). Next, as shown in FIG. 7, the 3D printing apparatus 100 scans each opening 50 of the electrode 5 arranged at the printing position B with the electron beam 11a, and irradiates the powder 3 with the electron beam 11a to print (step S208). The electron gun 11 adjusts the irradiation position in accordance with a control signal. In this embodiment, an electric field E is generated around the manufacturing area 2, and the powder 3 is pre-sintered using radiant heat from the heated electrode 5, thereby suppressing the smoke phenomenon caused by the powder 3 becoming negatively charged during manufacturing.

[0042] Next, the 3D modeling apparatus 100 determines whether or not the heated electrode 5 needs to be cooled based on the temperature sensor provided on the electrode 5 (step S209). If the 3D modeling apparatus 100 determines that the electrode 5 needs to be cooled (step S209: Yes), it supplies a cooling medium from a cooling device (not shown) to the cooling flow path 51 to cool the electrode 5 (step S210). This allows the 3D modeling apparatus 100 to prevent damage to the electrode 5 that has been excessively heated by the electron beam 11a. On the other hand, if the 3D modeling apparatus 100 determines that the electrode 5 does not need to be cooled (step S209: No), it proceeds to the next step S211 without cooling the electrode 5.

[0043] Next, the 3D printing apparatus 100 determines whether or not the formation of the object 1 is complete (step S211). If the formation of the first layer is complete but the formation of the second and subsequent layers is not complete, the 3D printing apparatus 100 determines that the formation of the object 1 is not complete (step S211: No). In this case, the 3D printing apparatus 100 raises the electrode 5 by the first movement mechanism 70 (step S212), and lowers the lifting stage 15 by the thickness of the next powder layer to adjust the height of the base plate 16, and then returns the procedure to step S202, thereby forming the second and subsequent powder layers.

[0044] The procedure from step S202 to step S212 is repeated until the formation of all layers of the object 1 is completed. When the formation of all layers of the object 1 is completed, the 3D printing device 100 determines that the formation of the object 1 is completed (step S211: Yes). The 3D printing device 100 lowers the electrode 5 by the first movement mechanism 70, brings the electrode 5 into contact with the upper surface of the printing area 2, and cools the object 1 (step S213). This allows the object 1 to be cooled quickly, which contributes to shortening the printing time. Note that the process of step S213 is not necessarily performed and may be omitted. Finally, the 3D printing device 100 raises the electrode 5 by the first movement mechanism 70 (step S214), and the production of the object 1 is completed.

[0045] 12 is a flowchart showing a second modification of the method for manufacturing a three-dimensional object according to the embodiment. Note that steps S301 to S308 are similar to steps S201 to S208 shown in FIG. 11, and therefore a description thereof will be omitted.

[0046] In step S308, the three-dimensional printing apparatus 100 scans the electron beam 11a over each opening 50 of the electrode 5 arranged at the printing position B, irradiates the powder 3 with the electron beam 11a, and prints the object 1. Then, the three-dimensional printing apparatus 100 determines whether the formation of the object 1 is complete (step S309). If the first layer has been printed but the second and subsequent layers have not, the three-dimensional printing apparatus 100 determines that the formation of the object 1 is not complete (step S309: No). In this case, the three-dimensional printing apparatus 100 raises the electrode 5 by the first movement mechanism 70 (step S310), lowers the lifting stage 15 by the thickness of the next powder layer to adjust the height of the base plate 16, and then returns the procedure to step S302, thereby forming the second and subsequent powder layers.

[0047] The procedure from step S302 to step S310 is repeated until all layers of the object 1 have been formed. When all layers of the object 1 have been formed, the 3D printing apparatus 100 determines that the formation of the object 1 has been completed (step S309: Yes). The 3D printing apparatus 100 supplies a cooling medium from a cooling device (not shown) to the cooling flow path 51 to cool the electrode 5 (step S311). Next, the 3D printing apparatus 100 lowers the electrode 5 using the first movement mechanism 70, bringing the cooled electrode 5 into contact with the upper surface of the printing area 2 and cooling the object 1 (step S312). This allows the object 1 to be cooled quickly, contributing to a reduction in the printing time. Note that the processes of step S311 and step S312 are not necessarily required and may be omitted. Finally, the three-dimensional modeling apparatus 100 causes the first movement mechanism 70 to raise the electrode 5 (step S313), and the production of the model 1 is completed.

[0048] 13 is a flowchart showing a third modification of the method for manufacturing a three-dimensional object according to the embodiment. Note that steps S401 to S408 are similar to steps S201 to S208 shown in FIG. 11, and therefore their explanation will be omitted.

[0049] In step S408, the 3D printing apparatus 100 scans the electron beam 11a over each opening 50 of the electrode 5 arranged at the printing position B, irradiates the powder 3 with the electron beam 11a to print the powder 3, and then supplies a cooling medium from a cooling device (not shown) to the cooling channel 51 to cool the electrode 5 (step S409). This allows the 3D printing apparatus 100 to prevent damage to the electrode 5 heated by the electron beam 11a. The 3D printing apparatus 100 then determines whether or not the formation of the object 1 has been completed (step S410). If the first layer has been printed but the second and subsequent layers have not yet been printed, the 3D printing apparatus 100 determines that the formation of the object 1 has not been completed (step S410: No). In this case, the three-dimensional modeling device 100 raises the electrode 5 using the first movement mechanism 70 (step S411), lowers the lifting stage 15 by the thickness of the next powder layer to adjust the height of the base plate 16, and then returns the procedure to step S402, thereby forming the second and subsequent powder layers.

[0050] The procedure from step S402 to step S411 is repeated until the formation of all layers of the object 1 is completed. When the formation of all layers of the object 1 is completed, the 3D printing apparatus 100 determines that the formation of the object 1 is completed (step S410: Yes). The 3D printing apparatus 100 lowers the electrode 5 by the first movement mechanism 70, brings the cooled electrode 5 into contact with the upper surface of the printing area 2, and cools the object 1 (step S412). This allows the object 1 to be cooled quickly, which contributes to shortening the printing time. Note that the process of step S412 is not necessarily performed and may be omitted. Finally, the 3D printing apparatus 100 raises the electrode 5 by the first movement mechanism 70 (step S413), and the production of the object 1 is completed.

[0051] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, and parts of the configurations may be omitted or modified without departing from the spirit of the invention.

[0052] Various aspects of the present disclosure are summarized below as appendices.

[0053] (Appendix 1) A three-dimensional modeling apparatus that irradiates an electron beam onto powder spread in a modeling area to melt and solidify the powder to form a three-dimensional model, an electron gun that emits the electron beam; a powder bed wall surrounding a building area where building is performed by irradiating the electron beam; a powder supplying means for supplying the powder to the building area; an electrode device for generating an electric field around the build area; The electrode device is an electrode having a plurality of slit-shaped openings arranged in a row to allow the electron beam emitted from the electron gun to pass therethrough, the electrode being disposed directly above the fabrication area; a power source that applies a potential difference between the electrode and the build area; a moving mechanism for moving the electrode to a target position, the electrode is disposed at a position directly above the printing area by the moving mechanism, and a voltage is applied to the electrode by the power supply, thereby generating an electric field around the printing area; A three-dimensional modeling apparatus characterized by: (Appendix 2) the movement mechanism includes a first movement mechanism that moves the electrode to a position directly above the manufacturing area, and a second movement mechanism that moves the electrode along a direction in which the openings are arranged. 2. The three-dimensional printing apparatus according to claim 1, (Appendix 3) A cooling flow path through which a cooling medium flows is formed inside the electrode, The electrode is cooled by the cooling medium flowing through the cooling channel. 3. The three-dimensional printing apparatus according to claim 1 or 2, (Appendix 4) A method for manufacturing a three-dimensional object by spreading powder on a manufacturing area and irradiating the powder with an electron beam to melt and solidify the powder, comprising: forming a powder layer by spreading the powder over the build area; disposing an electrode having a plurality of slit-shaped openings directly above the fabrication area; applying a voltage to the electrodes to generate an electric field around the build area; and irradiating the powder spread in the building area with an electron beam through the slit-shaped opening. A method for manufacturing a three-dimensional object, comprising: (Appendix 5) a step of irradiating the electrode disposed directly above the manufacturing area with the electron beam to heat the electrode, and pre-sintering the powder by radiant heat from the heated electrode; 5. The method for producing a three-dimensional object according to claim 4, (Appendix 6) A cooling flow path through which a cooling medium flows is formed inside the electrode, cooling the electrode by flowing the cooling medium through the cooling channel; 6. The method for producing a three-dimensional object according to claim 4 or 5. (Appendix 7) A cooling flow path through which a cooling medium flows is formed inside the electrode, a step of cooling the electrode by flowing the cooling medium through the cooling flow path, and bringing the cooled electrode into contact with a completed formed object to cool the object, 7. A method for producing a three-dimensional object according to any one of claims 4 to 6. [Explanation of symbols]

[0054] 1 object to be molded, 2 molding area, 3 powder, 4 electrode device, 5 electrode, 6 power supply, 7 movement mechanism, 10 chamber, 11 electron gun, 11a electron beam, 12 powder bed wall, 12a base, 13 powder supply means, 13a powder box, 13b recoater, 14 electron gun chamber, 15 lift stage, 16 base plate, 17 control device, 50 opening, 51 cooling channel, 70 first movement mechanism, 71 second movement mechanism, 70a ball screw, 70b mount, 70c linear guide, 100 three-dimensional molding device, E electric field, F electrostatic force.

Claims

1. A three-dimensional modeling apparatus that irradiates an electron beam onto powder spread in a modeling area to melt and solidify the powder to form a three-dimensional model, an electron gun that emits the electron beam; a powder bed wall surrounding a building area where building is performed by irradiating the electron beam; a powder supplying means for supplying the powder to the building area; an electrode device for generating an electric field around the build area; The electrode device is an electrode having a plurality of slit-shaped openings arranged in a row to allow the electron beam emitted from the electron gun to pass therethrough, the electrode being disposed directly above the fabrication area; a power source that applies a potential difference between the electrode and the build area; a moving mechanism for moving the electrode to a target position, the electrode is disposed at a position directly above the printing area by the moving mechanism, and a voltage is applied to the electrode by the power supply, thereby generating an electric field around the printing area; A three-dimensional modeling apparatus characterized by:

2. the movement mechanism includes a first movement mechanism that moves the electrode to a position directly above the manufacturing area, and a second movement mechanism that moves the electrode along a direction in which the openings are arranged. The three-dimensional modeling apparatus according to claim 1 .

3. A cooling flow path through which a cooling medium flows is formed inside the electrode, The electrode is cooled by the cooling medium flowing through the cooling channel. The three-dimensional modeling apparatus according to claim 1 or 2,

4. A method for manufacturing a three-dimensional object by spreading powder on a manufacturing area and irradiating the powder with an electron beam to melt and solidify the powder, comprising: forming a powder layer by spreading the powder over the build area; disposing an electrode having a plurality of slit-shaped openings directly above the fabrication area; applying a voltage to the electrodes to generate an electric field around the build area; and irradiating the powder spread in the building area with an electron beam through the slit-shaped opening. A method for manufacturing a three-dimensional object, comprising:

5. a step of irradiating the electrode disposed directly above the manufacturing area with the electron beam to heat the electrode, and pre-sintering the powder by radiant heat from the heated electrode; The method for manufacturing a three-dimensional object according to claim 4 .

6. A cooling flow path through which a cooling medium flows is formed inside the electrode, cooling the electrode by flowing the cooling medium through the cooling channel; The method for manufacturing a three-dimensional object according to claim 4 or 5.

7. A cooling flow path through which a cooling medium flows is formed inside the electrode, a step of cooling the electrode by flowing the cooling medium through the cooling flow path, and bringing the cooled electrode into contact with a completed formed object to cool the object, The method for manufacturing a three-dimensional object according to claim 4 or 5.

Images