WO2018193744A1

WO2018193744A1 - Three-dimensional manufacturing device

Info

Publication number: WO2018193744A1
Application number: PCT/JP2018/008939
Authority: WO
Inventors: 恭諒丸小; 武士物種
Original assignee: 三菱電機株式会社
Priority date: 2017-04-19
Filing date: 2018-03-08
Publication date: 2018-10-25
Also published as: JPWO2018193744A1; JP6639735B2

Abstract

Provided is a three-dimensional manufacturing device that can easily carry out sufficient preheating of powder material even when manufacturing large three-dimensional objects. A three-dimensional manufacturing device 100 is provided with: an electron gun 2 that irradiates powder material with an electron beam EB1; a manufacturing region forming unit 3 that is provided on the bottom surface 1a of an vacuum chamber 1 and wherein the powder material is spread and a powder layer 7 is formed; a pedestal 4 that is embedded in the powder layer 7 in an increased temperature state and preheats the powder material by thermal migration; and a radiation shield 10 that covers the manufacturing region forming unit 3 and is heated by thermal radiation from the pedestal 4. The powder material is preheated by thermal migration from the manufacturing region forming unit 3 and the radiated heat from the heated radiation shield 10.

Description

3D modeling equipment

The present application relates to a three-dimensional modeling apparatus that manufactures a three-dimensional modeled object by repeating a process of selectively solidifying a powder material made of metal particles, for example.

A three-dimensional shaped object is manufactured by irradiating a predetermined area of the powder layer formed of the powder material with a high-energy beam and selectively melting and solidifying the powder material by solidification or sintering. There is something. As the high energy beam, a laser or an electron beam is used. However, when an electron beam is used, it is possible to cope with a high melting point alloy and has a merit that a scanning speed is faster (for example, refer to Non-Patent Document 1). . As such a three-dimensional modeling apparatus, an apparatus that irradiates an electron beam onto a material arranged on a work area while supplying a reactive gas has been proposed (for example, see Patent Document 1). Further, a manufacturing apparatus for forming a three-dimensional layered object by repeating the process of modifying the surface by irradiating the latest sintered layer with an electron beam in a rare gas atmosphere has been proposed (for example, Patent Document 2).

On the other hand, as shown in Non-Patent Document 1, when an electron beam is used to melt and solidify a powder material, the powder material is negatively charged due to the interaction with the electron beam, and the individual powders are coulomb repulsive. Therefore, it is necessary to preheat the powder material of the powder layer to prevent scattering. The preheated powder material has a low electric resistance and is not charged to conduct the charge generated by the interaction with the electron beam, so that the above scattering does not occur. Therefore, in an apparatus for making a three-dimensional object using an electron beam, it has been proposed to raise the temperature of the powder material in advance by changing the beam current (beam output) and beam scanning speed of the electron beam (for example, Patent Document 3).

Special table 2011-506761 gazette Japanese Patent Laying-Open No. 2015-30872 Special table 2010-526694

However, in the method of performing preheating by changing parameters such as the beam output of an electron beam as in Patent Document 3, if the size of the three-dimensional structure to be manufactured is large and the surface area of the powder layer is large, the surface of the powder layer is There is a risk that preheating will be insufficient due to large heat loss due to heat radiation. This is because the high-energy electron beam that melts, solidifies, or sinters the powder material cannot be used in the preheating stage, and the beam output has an upper limit, so heat loss due to heat radiation is covered by adjusting the beam output. This is because it is difficult to do.

The present application has been made to solve the above-described problems, and provides a three-dimensional modeling apparatus that can easily sufficiently preheat a powder material even when a large three-dimensional model is manufactured. Is.

The three-dimensional modeling apparatus disclosed in the present application is a three-dimensional modeling apparatus that manufactures a three-dimensional structure by repeating a process of selectively solidifying a powder material forming a powder layer by irradiation with an electron beam. An electron beam irradiating means for irradiating the material with an electron beam, a modeling region forming portion provided on a surface opposite to the electron beam irradiating means, on which a powder material is spread and a powder layer is formed; Embedded in, and includes a preheating member that preheats the powder material by heat transfer, and a shield member that covers the modeling region forming part and raises the temperature by heat radiation from the preheating member. It is preheated by heat radiation from the shield member whose temperature has been raised.

According to the three-dimensional modeling apparatus disclosed in the present application, sufficient preheating of the powder material can be easily performed even when a large three-dimensional model is manufactured.

1 is a schematic diagram showing a three-dimensional modeling apparatus in Embodiment 1. FIG. 1 is a perspective view showing an outline of a radiation shield according to Embodiment 1. FIG. 3 is a plan view showing a frame of a radiation shield according to Embodiment 1. FIG. It is a figure which shows the metal plate which comprises the side part of the radiation shield which concerns on Embodiment 1. FIG. FIG. 5 is a diagram for explaining the operation of the three-dimensional modeling apparatus in the first embodiment. 6 is a perspective view of a radiation shield according to a modification of the first embodiment. FIG. It is a perspective view which shows the outline | summary of the radiation shield which concerns on Embodiment 2. FIG. It is a perspective view which shows the outline | summary of the radiation shield which concerns on Embodiment 3. FIG. FIG. 10 is a schematic diagram showing a three-dimensional modeling apparatus in a fourth embodiment. FIG. 10 is a schematic diagram illustrating a three-dimensional modeling apparatus in a fifth embodiment.

Embodiment 1 FIG.
The first embodiment will be described below with reference to FIGS. FIG. 1 is a schematic diagram illustrating a three-dimensional modeling apparatus according to Embodiment 1. In the three-dimensional modeling apparatus 100, an electron gun 2 that irradiates an electron beam EB1 downward, that is, an electron beam irradiation means, is provided above the vacuum chamber 1, and a ceiling surface 1b of the vacuum chamber 1, that is, a modeling region forming unit, An opening (not shown) through which the electron beam EB1 passes is provided on the opposite surface. The electron gun 2 faces the modeling region forming unit 3 formed on the floor surface 1 a of the vacuum chamber 1, and can irradiate the inside of the modeling region forming unit 3 with the electron beam EB 1. The modeling region forming unit 3 has a square horizontal section of 90 mm × 90 mm, for example, and the inside thereof becomes a modeling region of a three-dimensional modeled object, and a powder layer 7 made of a powder material is formed.

The powder material is a powdery material that solidifies to form a three-dimensional structure, and is irradiated with the electron beam EB1 from the electron gun 2 to be melted or solidified or sintered to become a solidified body 8. The powder material constituting the powder layer 7 is, for example, a powder material of metal particles such as cobalt chromium molybdenum alloy or titanium alloy, but is not limited thereto, and can be melted, solidified or sintered by irradiation with an electron beam. Anything is acceptable. The powder layer 7 is formed by supplying a predetermined amount of powder material while the powder material supply unit 93 moves on and around the modeling region forming unit 3 and laying the powder material in layers inside the modeling region forming unit 3. It is what is done. The powder material supplied by the powder material supply unit 93 is stored in a powder material storage unit 92 that is, for example, a rectangular parallelepiped box. When the powder material supply unit comes downward, the powder material storage unit 92 drops the powder material and supplies the powder material to the powder material supply unit 93. Since the electron beam EB1 only needs to be irradiated from the electron gun 2 to the modeling region forming unit 3, the position where the modeling region forming unit 3 is provided is not limited to the floor surface 1a, but any surface that faces the electron gun 2. Good. For example, a work table (not shown) may be installed on the floor surface 1a, and the modeling area forming unit 3 may be provided on the upper surface.

At the bottom of the modeling area forming unit 3, a modeling table 5 is provided that can slide up and down. The modeling table 5 is moved up and down by a lifting mechanism 6 provided below, and the depth of the modeling region forming unit 3 can be adjusted by operating the lifting mechanism 6. FIG. 1 shows a state in which the modeling table 5 is lowered from the floor surface 1a by two layers of the powder layer 7, the first powder layer 7 below the broken line, and the second powder above the broken line. Layer 7. The first powder layer 7 is formed thick to cover the periphery of the pedestal 4, but the second and subsequent powder layers 7 are formed with a thickness of about several tens of μm.

The pedestal 4 in a heated state is embedded in the first powder layer 7. The pedestal 4 serves as a base portion of the three-dimensional structure and functions as a preheating member for the powder material. The material of the pedestal 4 is not particularly limited as long as the temperature is raised by irradiation with an electron beam, but a material having a large heat capacity is preferable.

A radiation shield 10 that is supported at a predetermined height by a support jig 91 and covers the entire modeling region forming unit 3 is provided above the modeling region forming unit 3. In the side view, the radiation shield 10 has a trapezoidal shape that expands toward the lower side, that is, closer to the modeling region forming portion 3, and the cross-sectional area in the direction parallel to the floor surface 1a increases toward the lower side. The height at which the radiation shield 10 is installed is not particularly limited as long as it does not hinder the movement of the powder material supply unit 93. The radiation shield 10 is provided with an opening 10c facing the electron gun 2 at the upper end, an opening 10b facing the modeling region forming portion 3 at the lower end, and a hollow portion 10a through which the electron beam EB1 passes from the upper end to the lower end. Therefore, the radiation shield 10 does not prevent the irradiation of the electron beam EB1 from the electron gun 2 to the modeling region forming unit 3.

2 is a perspective view showing an outline of the radiation shield according to the first embodiment, FIG. 3 is a plan view showing an upper frame of the radiation shield, and FIG. 4 is a metal plate constituting a side portion of the radiation shield. That is, it is a figure which shows a plate-shaped member. As shown in FIG. 2, the radiation shield 10 is disposed at the upper end of the radiation shield 10, and a first side surface portion 13 and a second side surface portion 14 are arranged on each side of a rectangular frame 12 constituting the upper surface 11 of the radiation shield 10. The first side surface portion 13 and the second side surface portion 14 are each attached to the frame 12 by screws 19 in pairs.
The first side surface portion 13 extends downward from the upper surface 11 of the radiation shield 10, that is, in the direction of the modeling region forming portion 3, and is attached to the upper surface 11 at a right angle. The second side surface portion 14 extends downward from the upper surface 11 and is attached to the upper surface 11 at an angle of 45 °. Thus, since the second side surface portion 14 forms an angle of 45 ° with respect to the upper surface 11 of the radiation shield 10, the radiation shield 10 and the hollow portion 10a are shaped to expand downward.
In the first embodiment, the second side surface portion 14 forms an angle of 45 ° with respect to the upper surface 11. However, since the radiation shield 10 only needs to expand downward, the second side surface portion 14 The angle formed with respect to the upper surface 11 is not limited to 45 °, and may be an acute angle. In addition, the first side surface portion 13 is attached at a right angle to the upper surface 11, but the first side surface portion 13 may be attached at an acute angle to the upper surface 11 in the same manner as the second side surface portion 14. Good.

As shown in FIG. 3, the frame 12 has an opening 10 c having a size of, for example, 38 mm × 38 mm formed in the approximate center. Further, the frame 12 is provided with bent portions 12b at both left and right ends in the figure. The bent portion 12b is bent downward at an angle of 45 ° with respect to the upper surface 11, and the second side surface portion 14 is attached to the upper surface side. Also, two screw holes 12c through which the screws 19 pass are formed in the bent portion 12b.
The first side surface portion 13 is formed by overlapping the metal plates 131 shown in FIG. 4A in triplicate, and screw holes 13c of the respective metal plates 131 and screw holes formed in the side portions of the frame 12 (not shown). It is attached to the frame 12 with a screw 19 penetrating through. The metal plate 131 has a trapezoidal shape in plan view, and has, for example, an upper side 13a having a length of 47 mm and an angle of 135 ° with the upper side 13a, for example, a hypotenuse 13b having a length of 74 mm. Here, since the upper side 13 a is parallel to the upper surface 11 of the radiation shield 10, the oblique side 13 b forms an angle of 45 ° downward with respect to the upper surface 11. The second side surface portion 14 is formed by overlapping the metal plates 141 shown in FIG. 4B in a triple manner, and is attached to the frame 12 by screws 19 passing through the screw holes 14c of the respective metal plates 141 and the screw holes 12c of the frame 12. It is attached. The metal plate 141 has a rectangular shape in plan view, and has, for example, a short side 14a having a length of 54 mm and a long side 14b having a length of 74 mm, for example. The material of the metal plate 131 and the metal plate 141 is, for example, SUS304, and the thickness is 0.5 mm to 1 mm. When the metal plate 131 and the metal plate 141 are stacked, a space of about 2 mm is provided between the metal plate 131 and the metal plate 141 adjacent to each other with a washer or the like interposed therebetween. Note that the number and interval of the metal plates 131 and the metal plates 141 to be stacked are not limited to the above, and the plurality of metal plates 131 and the metal plates 141 may be stacked at intervals.

Next, the operation will be described. FIG. 5 is a diagram for explaining the operation of the three-dimensional modeling apparatus in the first embodiment. A powder material is spread over the modeling region forming unit 3 to form the first powder layer 7, and then the pedestal 4 is embedded on the upper surface of the first powder layer 7. When the pedestal 4 is heated by irradiating the pedestal 4 with a preheating electron beam EB2, which is an electron beam having an energy density smaller than that of the electron beam EB1 for melting and solidifying the powder material, as shown in FIG. In addition, heat radiation H2 is generated above the pedestal 4, and heat transfer H1 including heat conduction and heat radiation is generated laterally and below the pedestal 4. Since the radiation shield 10 covers the entire modeling region forming unit 3 as described above, most of the upward heat radiation H2 is collected and heated. The heat transfer H1 raises the temperature of the powder layer 7 and the modeling region forming unit 3 surface.

When the surface of the radiation shield 10 and the modeling region forming part 3 is heated, the heat radiation H2 to the first powder layer 7 and the base 4 is generated from the heated radiation shield 10 as shown in FIG. . Further, heat transfer H1 to the first powder layer 7 and the pedestal 4 is generated from the surface of the modeling region forming portion 3 that has been heated. The first powder layer 7 is heated by heat transfer H 1 from the pedestal 4, heat transfer H 1 from the surface of the modeling region forming unit 3, and heat radiation H 2 from the radiation shield 10.

After the temperature of the first powder layer 7 is increased, the modeling table 5 and the first powder layer 7 are lowered by the lifting mechanism 6 to form a space as shown in FIG. The second powder layer 7 is formed in the same manner as described above. When forming the second powder layer 7, the first powder layer 7, the surface of the modeling region forming portion 3, and the radiation shield 10 are in a sufficiently heated state, and therefore the first powder layer 7 and Heat transfer H1 is generated from the pedestal 4 to the second powder layer 7, and heat radiation H2 is generated from the radiation shield 10 to the second powder layer 7. The second powder layer 7 is preheated by these heat transfer H1 and heat radiation H2 to a temperature at which the powder material does not scatter even when irradiated with the preheating electron beam EB2. Thereafter, as shown in FIG. 5 (d), the preheating electron beam EB2 is irradiated onto the second powder layer 7, and the two layers are heated to a temperature at which no scattering occurs even when the electron beam EB1 for melting and solidifying the powder material is irradiated. Preheat the powder layer 7 of the eye. The heat transfer H1 from the first powder layer 7 and the pedestal 4 and the heat radiation H2 from the radiation shield 10 are also generated during preheating by the preheating electron beam EB2. That is, the second powder layer 7 is irradiated with the preheating electron beam EB2, in addition to the pedestal 4, the first powder layer 7 and the heat transfer H1 from the surface of the modeling region forming portion 3, and the radiation shield 10. It is also preheated by the heat radiation H2.

After preheating the second powder layer 7, as shown in FIG. 5 (e), the electron beam EB1 is selectively irradiated to the powder material of the powder layer 7, and the powder material in a desired range is melted and solidified to be solidified. 8 is generated. After the formation of the solidified body 8, the modeling table 5 is further lowered, and the formation of the third and subsequent powder layers 7, preheating and generation of the solidified body are repeated in the same manner as in the case of the second layer.

In the first embodiment, the temperature of the pedestal 4 embedded in the first powder layer 7 is raised by irradiating the preheating electron beam EB2 emitted from the electron gun 2. Is not limited to this. For example, the pedestal 4 that has been heated in advance with a heater or the like may be embedded in the first powder layer 7. In short, the state in which the heated pedestal 4 is embedded in the first powder layer 7 continues for a certain time or more, and the radiation shield 10 is heated by the heat radiation H2 from the pedestal 4, and the heat from the pedestal 4 is increased. The powder layer 7 may be preheated by the movement H1 and the heat radiation H2 from the radiation shield 10 whose temperature has been raised.

As described above, the radiation shield 10 is configured such that the first side surface portion 13 and the second side surface portion 14 are stacked with the three metal plates 131 and the metal plates 141 being spaced apart from each other. The thermal resistance between each metal plate 131 and between each metal plate 141 is large. For this reason, the temperature rise of the metal plate 131 and the metal plate 141 closest to the modeling region forming unit 3 is faster than the case where the metal plate 131 and the metal plate 141 are stacked without a gap. In addition, the heat capacity of the first side surface portion 13 and the second side surface portion 14 is larger than when only one metal plate is used, and the temperature of the radiation shield 10 is maintained at a high temperature for a longer time.

In order to investigate the contribution of the radiation shield 10 to the preheating of the powder layer 7, the temperature rise time and the temperature rise rate of the base 4 when the radiation shield 10 was not provided and when the radiation shield 10 was provided were measured. The measurement is performed in a state where the pedestal 4 is embedded in the upper surface of the first powder layer 7 formed inside the modeling region forming unit 3 as in FIG. 5A and attached to the lower portion of the pedestal 4. The temperature at the mounting position of the thermocouple was defined as the temperature of the base 4. When the radiation shield 10 is not provided, the time required to raise the temperature of the pedestal 4 to 850 ° C. is 1200 seconds (temperature increase rate: 0.69 ° C./second), whereas the radiation shield 10 is provided. In this case, it was 640 seconds (temperature increase rate: 1.21 ° C./second). The difference between the temperature raising time and the temperature raising speed is considered to be because, if there is no radiation shield 10, energy that causes heat loss due to upward heat radiation is collected and reused by the radiation shield 10. .

Further, as a result of measuring the temperature difference between the center portion and the end portion of the pedestal 4 until the temperature of the pedestal 4 reaches 850 ° C. and measuring the temperature difference between the center portion and the end portion, the radiation shield 10 is provided. The maximum temperature difference when the radiation shield 10 is provided is 160 ° C., and the temperature unevenness is reduced by 90 ° C. This is considered to be because the effect of recovery and reuse of the heat radiation H2 by the radiation shield 10 is large at the end portion where the loss due to the heat radiation H2 is larger than that at the center, and the temperature unevenness is reduced.

In addition, although the contribution of the radiation shield 10 when raising the temperature of the pedestal 4 has been described here, the same applies to the case where the powder layer 7 is preheated. Since the radiation shield 10 covers the entire modeling region forming unit 3 on which the powder layer 7 is formed, the radiating base 2 and the modeling region forming unit 3 and the heat radiation H2 emitted upward from the surface of the powder layer 7 are generated. In addition to the recovery, the temperature of the recovered heat radiation H2 is raised to generate the heat radiation H2 to the powder layer 7, which contributes to preheating of the powder layer 7 and reduction of temperature unevenness. In particular, when the three-dimensional structure to be manufactured is large and the surface area of the modeling region forming part 3 and the powder layer 7 is large, the upward radiation of heat is also large, so the radiation shield 10 is considered to contribute greatly.

Since the heat radiation of the modeling region forming unit 3 and the powder layer 7 is emitted in all directions and there is also heat radiation that leaks from the space between the radiation shield 10, the radiation shield 10 is formed as much as possible in the modeling region forming unit 3. It is preferable to arrange them close to each other. As described above, the height of the radiation shield 10 needs to be in a range in which the powder material supply unit does not hinder the movement of the 93. For example, the radiation shield 10 is replaced by a support member capable of adjusting the height instead of the support jig 91. You may make it the structure which supports. In this case, when forming the powder layer 7, the radiation shield 10 is arranged so as not to hinder the movement of the powder material supply unit 93, and in other cases, the radiation shield 10 is arranged as low as possible to form the modeling region forming unit. More heat radiation H2 can be recovered by approaching 3.
Further, since the heat radiation H2 from the radiation shield 10 depends on the heat radiation property of the surface, the lower surface of the metal plate 131 and the metal plate 141, that is, the surface facing the modeling region forming portion 3 is subjected to alumite processing so that the radiation shield. The heat dissipation of 10 may be improved.

According to Embodiment 1, even when a large three-dimensional structure is manufactured, sufficient preheating of the powder material can be easily performed. More specifically, the pedestal heated by the preheating electron beam, the heat radiation emitted upward from the surface of the modeling region forming part heated by the heat transfer from the pedestal, by a radiation shield covering the entire modeling region forming part Even when there is a risk of increasing heat loss due to upward heat radiation, especially when manufacturing a large three-dimensional structure for recovery and reuse, the temperature drop of the powder layer due to heat radiation is suppressed. Sufficient preheating of the powder layer is facilitated.

Also, in the preheating of the second and subsequent powder layers, the energy density of the preheating electron beam can be made smaller than before. More specifically, in the second and subsequent powder layers, in addition to the preheating electron beam irradiation, heat transfer from the pedestal, the first powder layer and the modeling region forming part surface, and heat from the radiation shield Since it is also preheated by radiation, the energy density of the preheating electron beam can be made smaller than before.

Moreover, sufficient preheating of the powder layer can be performed more stably. More specifically, the heat radiation from the end portion where the loss due to heat radiation is larger is recovered by the radiation shield and reused to reduce the temperature unevenness between the center portion and the end portion. Preheating can be performed more stably. In particular, the larger the three-dimensional structure to be manufactured, the greater the temperature unevenness, and there is a risk that sufficient preheating will not be performed at the end, but sufficient preheating is more stable by reducing the temperature unevenness as described above. Can be done.

Also, the time during which the radiation shield contributes to the preheating of the powder layer can be made longer. More specifically, the heat capacity of the first side surface portion and the second side surface portion is increased by overlapping the metal plates constituting the first side surface portion and the second side surface portion of the radiation shield in triplicate. Therefore, the high temperature state of the heated radiation shield can be maintained, and the time that contributes to the preheating of the powder layer by thermal radiation can be made longer.

Also, the effect of suppressing the temperature drop of the powder layer by the radiation shield can be obtained earlier. More specifically, the metal plates constituting the first side surface portion and the second side surface portion of the radiation shield are overlapped with a space between each other, so that the metal plates are brought into contact with each other rather than the metal plates in contact with each other. Since the thermal resistance between the metal plate and the forming area forming part is increased, the temperature rise rate of the metal plate is faster, and the heat radiation from the radiation shield starts earlier, thereby suppressing the temperature drop of the powder layer. It can be obtained earlier.

Also, the installation space for the radiation shield can be reduced. More specifically, by attaching the second side surface portion at an angle of 45 ° to the upper surface of the radiation shield, the radiation shield is shaped to expand downward, so that the modeling region forming portion Since the cross-sectional area in the direction parallel to the floor of the vacuum chamber is increased as it is closer, the lower part of the radiation shield is secured while ensuring the cross-sectional area necessary to cover the entire forming area forming part in the lower part, thereby reducing the radiation shield. The installation space can be suppressed.

Here, a modification of the first embodiment will be described. FIG. 6 is a perspective view of a radiation shield according to a modification of the first embodiment. The radiation shield 101 is obtained by forming an opening 101 a corresponding to the hollow portion 10 a of the radiation shield 10 on a flat plate 121 that covers the entire modeling region forming portion 3. The flat plate 121 collects heat radiation from the pedestal 4 and the like and raises the temperature. After the temperature rise, the flat plate 121 generates heat radiation downward to contribute to preheating of the powder layer 7. Since the radiation shield 101 does not have a side surface portion, heat radiation from the pedestal 4 and the like is likely to leak as compared with the radiation shield 10 of the first embodiment, but the configuration is very simple.

Embodiment 2. FIG.
Below, Embodiment 2 is demonstrated based on FIG. The same or corresponding parts as those in FIGS. 1 to 4 are denoted by the same reference numerals, and the description thereof is omitted. The second embodiment is different from the first embodiment in the shape of the radiation shield. FIG. 7 is a perspective view showing an outline of the radiation shield according to the second embodiment. The radiation shield 20 has rectangular frames 22A to 22C having different sizes arranged in parallel to each other, and the first side surface constituting members 23A to 23C and the second side surface constituting members 24A to 24C are screwed to the respective frames. The first side surface portion 23 and the second side surface portion 24 are configured by being attached by 29 without a gap. A hollow portion (not shown) is formed in the radiation shield 20 from the upper end to the lower end.

The smallest frame 22A among the frames 22A to 22C is disposed at the upper end portion of the radiation shield 20 and constitutes the upper surface 21 of the radiation shield 20. A first side surface constituting member 23A and a second side surface constituting member 24A are attached to the frame 22A. The first side surface constituting member 23 A extends downward from the upper surface 21 of the radiation shield 20, that is, in the direction of the modeling region forming unit 3, and is attached to the upper surface 21 at a right angle. The second side surface component member 24 A extends downward from the upper surface 21 and is attached to the upper surface 21 at an angle of 30 °.
The intermediate size frame 22B is disposed below the frame 22A by the height of the first side surface component member 23A, and the first side surface component member 23B and the second side surface component member 24B are attached thereto. The first side surface constituting member 23B is attached at a right angle to the frame 22B, and the second side surface constituting member 24B is attached at an angle of 45 ° to the frame 22B. Here, since the frame 22B is arranged in parallel to the frame 22A and is also parallel to the upper surface 21, the first side surface constituting member 23B is also perpendicular to the upper surface 21, and the second side surface constituting member 24B is The upper surface 21 also forms a 45 ° angle.
The largest frame 22C is disposed below the frame 22B by the height of the first side surface constituting member 23B, and the first side surface constituting member 23C and the second side surface constituting member 24C are attached thereto. The first side surface constituting member 23C is attached at a right angle to the frame 22C, and the second side surface constituting member 24C is attached at an angle of 60 ° to the frame 22C. Here, since the frame 22C is arranged in parallel with the frame 22A and is also parallel to the upper surface 21, the first side surface constituting member 23C is also perpendicular to the upper surface 21, and the second side surface constituting member 24C is The upper surface 21 also forms an angle of 60 °.
As described above, in the second embodiment, the angles formed by the second side surface constituting members 24A to 24C and the upper surface 21 are 30 °, 45 °, and 60 °, and gradually increase toward the bottom.

In order to attach the second side surface constituting members 24A to 24C to the frames 22A to 22C at an acute angle, a bent portion is provided like the frame 12 of the first embodiment, and the upper surface of the bent portion is bent downward. The second side surface constituting members 24A to 24C may be attached to each other. Further, the first side surface constituting members 23A to 23C and the second side surface constituting members 24A to 24C are constituted by three metal plates which are overlapped with each other with a spacing of 2 mm, as in the first embodiment. Yes.

In order to investigate the contribution of the radiation shield 20 to the preheating of the powder layer 7, the temperature raising time and the temperature raising rate of the base 4 when the radiation shield 20 was provided were measured in the same manner as in the first embodiment. When the radiation shield 20 is provided, the time required to raise the temperature of the pedestal 4 to 850 ° C. is 610 seconds (temperature increase rate: 1.31 ° C./second), and the radiation shield 10 of the first embodiment is provided. It was confirmed that the time was further shortened by 30 seconds. As for temperature unevenness, the maximum temperature difference was 75 ° C., and it was confirmed that the temperature unevenness was further reduced by 85 ° C. compared to the case where the radiation shield 10 was provided. This is because the angle formed between the second side surface component 24C closest to the modeling region forming portion 3 and the upper surface 21 of the radiation shield 20 is 60 °, and the second side surface portion 14 and the upper surface 11 of the radiation shield 10 This is considered to be because it is larger than 45 ° which is an angle formed by. That is, as the angle formed with the upper surface of the radiation shield is larger (closer to the right angle), the heat radiation H2 leaking to the side from the gap between the radiation shield 10 or the radiation shield 20 and the pedestal 4 decreases, and the heat radiation H2 from the pedestal 4 is reduced. It is thought that the rate of temperature increase was further increased because more collection and reuse were possible. Moreover, since it is considered that the heat radiation H2 leaking to the side is emitted from the end rather than from the center of the base 4, the temperature drop at the end is further reduced, and the temperature unevenness is also reduced. Conceivable.
In addition, since the radiation shield 20 covers the modeling area formation part 3 whole in which the powder layer 7 is formed, it is thought that the same effect is acquired also when the powder layer 7 is preheated.
Others are the same as those in the second embodiment, and the description thereof is omitted.

According to the second embodiment, the same effect as in the first embodiment can be obtained.

Further, the temperature rise rate during preheating of the powder layer 7 can be further increased, and temperature unevenness can be further reduced. More specifically, the angle formed by the second side surface component member with respect to the upper surface of the radiation shield is increased stepwise to reduce heat radiation leaking between the modeling region forming portion and the radiation shield. Therefore, it is possible to collect and reuse more heat radiation particularly from the end, further increasing the rate of temperature rise and further reducing temperature unevenness.

Embodiment 3 FIG.
The third embodiment will be described below with reference to FIG. The same or corresponding parts as those in FIGS. 1 to 4 are denoted by the same reference numerals, and the description thereof is omitted. The third embodiment is different from the first and second embodiments in the shape of the radiation shield. FIG. 8 is a perspective view showing an outline of the radiation shield according to the third embodiment. The radiation shield 30 includes side surfaces 33 that form paraboloids as a whole by arranging frames 32A to 32C having different sizes in parallel to each other and attaching a plurality of side surface members 33A with screws 39 without gaps. Is. A hollow portion (not shown) is formed in the radiation shield 30 from the upper end to the lower end.

The smallest frame 32A among the frames 32A to 32C is arranged at the upper end of the radiation shield 30 and constitutes the upper surface 31 of the radiation shield 30. A side surface member 33A is attached to the frame 32A, and the side surface member 33A extends downward from the upper surface 31 of the radiation shield 30, that is, in the direction of the modeling region forming portion 3. The intermediate-sized frame 32B is disposed below the frame 32A by the height of the side surface component 33A, and the side surface component 33B is attached thereto. The largest frame 32C is disposed below the frame 32B by the height of the side surface component 33B, and the side surface component 33C is attached thereto. Each of the side surface constituting members 33A to 33C is composed of three metal plates which are bent so as to form a parabolic surface as a whole of the side surface portion 33 and are overlapped with each other with an interval of 2 mm. The side surface constituting members 33A to 33C are attached so that the lower surface of the side surface portion 33, that is, the surface facing the modeling region forming portion 3 forms a paraboloid. An acute angle is formed, and the angle is larger toward the lower side. For this reason, the angle between the upper surface 31 and the side surface component 33B is larger than that of the side surface member 33B, and the side surface member 33C is larger than the side surface member 33B. Others are the same as those in the second embodiment, and the description thereof is omitted.

According to the third embodiment, the same effect as in the second embodiment can be obtained.

Embodiment 4 FIG.
Below, Embodiment 4 is demonstrated based on FIG. 1 to 8 are assigned the same reference numerals, and descriptions thereof are omitted. FIG. 9 is a schematic diagram illustrating a three-dimensional modeling apparatus according to the fourth embodiment. In the three-dimensional modeling apparatus 200, the radiation shield 40 is provided with an opening 40c facing the electron gun 2 at the upper end and an opening 40b facing the modeling region forming unit 3 at the lower end, and a hollow through which the electron beam EB1 passes. The part 40a is formed inside from the upper end to the lower end. As with the radiation shield 10 of the first embodiment, the radiation shield 40 has a trapezoidal shape that becomes narrower as viewed from the side, that is, as it is farther from the modeling region forming unit 3, and as it extends upward, it is cut in a direction parallel to the floor surface 1 a. The area is getting smaller. Further, the height of the opening 40b at the lower end is the same as that of the opening 10b of the radiation shield 10, but the side surface of the radiation shield 40 extends above the radiation shield 10 and the height of the opening 40c at the upper end. Is higher than the opening 10 c at the upper end of the radiation shield 10. More specifically, the distance D2 between the opening 40c at the upper end and the ceiling surface 1b of the vacuum chamber 1 is considered to be an example where the distance D1 between the opening 40b at the lower end and the powder layer 7 is equal to or less. It is done. The smaller the distance D2 between the opening 40c and the ceiling 1b surface of the vacuum chamber 1, the higher the opening 40c and the smaller the cross-sectional area of the opening 40c. Therefore, the distance D2 is preferably as small as possible. Others are the same as those in the first embodiment, and thus the description thereof is omitted.

According to the fourth embodiment, the same effect as in the first embodiment can be obtained.

Further, by extending the side surface upward in the trapezoidal radiation shield whose cross-sectional area becomes smaller toward the upper side, the height of the opening on the modeling region forming unit side is kept low and provided on the side opposite to the modeling region forming unit. The height of the opening was increased, and the cross-sectional area of the opening on the side opposite to the modeling region forming part was further reduced. For this reason, while maintaining the amount of heat radiation recovered from the modeling region, the recovered heat radiation is prevented from leaking from the opening on the side opposite to the modeling region forming part, and the powder layer is preheated more efficiently. It can be carried out.

Embodiment 5 FIG.
Below, Embodiment 5 is demonstrated based on FIG. The same or corresponding parts as those in FIGS. 1 to 9 are denoted by the same reference numerals, and the description thereof is omitted. In the fifth embodiment, the side surface of the radiation shield extends further upward than in the fourth embodiment. FIG. 10 is a schematic diagram illustrating a three-dimensional modeling apparatus according to the fifth embodiment. In the three-dimensional modeling apparatus 300, the radiation shield 50 is provided with an opening 50c facing the electron gun 2 at the upper end and an opening 50b facing the modeling region forming unit 3 at the lower end, and a hollow through which the electron beam EB1 passes. The part 50a is formed inside from the upper end to the lower end. As with the radiation shield 10 of the first embodiment, the radiation shield 50 has a trapezoidal shape that becomes narrower as viewed from the upper side, that is, as it is farther from the modeling region forming unit 3, and as it extends upward, it is cut in a direction parallel to the floor surface 1 a. The area is getting smaller. Further, the side surface of the radiation shield 50 extends upward from the radiation shield 10, the upper end opening 50 c comes into contact with the ceiling surface 1 b of the vacuum chamber 1, and the gap between the opening 50 c and the ceiling surface 1 b is closed. Yes. Others are the same as those in the first embodiment, and thus the description thereof is omitted.

According to the fifth embodiment, the same effect as in the fourth embodiment can be obtained.

Also, the opening provided on the side opposite to the modeling area forming part is brought into contact with the ceiling surface of the vacuum chamber, and the gap between the opening provided on the side opposite to the modeling area forming part and the ceiling surface is closed. Therefore, while maintaining the amount of heat radiation recovered from the modeling area, the recovered heat radiation is more reliably suppressed from leaking from the opening on the side opposite to the modeling area, and the powder layer is preheated more efficiently. It can be carried out.

Although this application describes various exemplary embodiments and examples, various features, aspects, and functions described in one or more embodiments may be applied to particular embodiments. The present invention is not limited to this, and can be applied to the embodiments alone or in various combinations.
Accordingly, innumerable modifications not illustrated are envisaged within the scope of the technology disclosed in the present application. For example, the case where at least one component is deformed, the case where the component is added or omitted, the case where the at least one component is extracted and combined with the component of another embodiment are included.

1 vacuum chamber, 1a floor surface, 1b ceiling surface, 2 electron gun, 3 modeling area forming part, 4 pedestal (preheating member), 7 powder layer, 10, 101, 20, 30, 40, 50 radiation shield, 10a, 40a , 50a hollow portion, 10b, 10c, 101a, 40b, 40c, 50b, 50c opening portion, 11, 21, 31 upper surface, 13, 23 first side surface portion, 23A to 23C first side surface constituting member, 14, 24 Second side part, 24A-24C Second side constituent member, 33 side part, 33A-33C side constituent member, 131, 141 metal plate, 100, 200, 300 three-dimensional modeling apparatus, EB1 electron beam, EB2 preheating Electron beam, H1 heat transfer, H2 heat radiation

Claims

A three-dimensional modeling apparatus for manufacturing a three-dimensional structure by repeating a step of selectively solidifying a powder material forming a powder layer by irradiation with an electron beam,
An electron beam irradiation means for irradiating the powder material with an electron beam;
A modeling region forming portion provided on a surface facing the electron beam irradiation means, and a powder layer of the powder material is formed;
A preheating member that is embedded in the powder layer in a heated state and preheats the powder material by heat transfer;
A cover member that covers the modeling region forming part and that is heated by heat radiation from the preheating member;
The three-dimensional modeling apparatus, wherein the powder material is preheated by heat transfer from the preheating member and heat radiation from the heated shield member.
The three-dimensional modeling apparatus according to claim 1, wherein the temperature of the preheating member is raised by a preheating electron beam irradiated by the electron beam irradiation means.
The three-dimensional modeling apparatus according to claim 1 or 2, wherein the shield member has a larger cross-sectional area in a direction parallel to a surface on which the modeling region forming unit is provided, as it is closer to the modeling region forming unit.
The tertiary according to any one of claims 1 to 3, wherein the shield member includes a side surface portion extending in a direction of the modeling region forming portion and forming an acute angle with respect to an upper surface of the shield member. Original modeling device.
5. The three-dimensional modeling apparatus according to claim 4, wherein the side surface portion is a plurality of plate-like members that are stacked with a space therebetween.
The three-dimensional modeling apparatus according to claim 5, wherein the plate-like members are stacked in a triple manner.
The 3D modeling apparatus according to any one of claims 4 to 6, wherein the acute angle is larger as the side surface portion is closer to the modeling region forming unit.
The three-dimensional modeling apparatus according to any one of claims 4 to 7, wherein a surface of the side surface portion facing the modeling region forming unit is a parabolic surface.
9. The shield member according to any one of claims 4 to 8, wherein an opening provided on a side opposite to the modeling region forming portion is in contact with a surface facing the modeling region forming portion. The three-dimensional modeling apparatus described.