JPWO2018193744A1 - Three-dimensional modeling device - Google Patents

Abstract

A three-dimensional shaping apparatus capable of easily performing sufficient preheating of powder material even when producing a large three-dimensional shaped article is obtained. In the three-dimensional modeling apparatus 100, an electron gun 2 for irradiating a powder material with an electron beam EB1 and a modeling area forming unit 3 provided on the floor surface 1a of the vacuum chamber 1 and having the powder material spread to form a powder layer 7 And a pedestal 4 which is embedded in the powder layer 7 in a heated state and which preheats the powder material by heat transfer, and a radiation shield 10 which covers the shaping region forming portion 3 and which is heated by heat radiation from the pedestal 4 The powder material is preheated by the heat transfer from the shaping region forming unit 3 and the heat radiation from the heated radiation shield 10.

Description

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

  A three-dimensional shaped object is manufactured by repeating a process of selectively melting, solidifying or sintering the powder material by irradiating a high energy beam to a predetermined region of the powder layer formed by the powder material, and repeating the process of solidifying or sintering the powder material. There is something. A laser or an electron beam is used as the high energy beam, but when an electron beam is used, it is also possible to cope with high melting point alloys, and there is an advantage that the scanning speed is faster (see, for example, Non-Patent Document 1) . Conventionally, as such a three-dimensional modeling apparatus, an apparatus has been proposed which irradiates a material disposed on a work area with an electron beam while supplying a reactive gas (see, for example, Patent Document 1). In addition, a manufacturing apparatus has been proposed that forms a three-dimensional laminated molded object by repeating the process of irradiating the latest sintered layer with an electron beam in a rare gas atmosphere to reform the surface (for example, Patent Document 2).

  On the other hand, as shown in Non-Patent Document 1, when using an electron beam to melt and solidify the powder material, the powder material is negatively charged due to the interaction with the electron beam, and the individual powders are coulombic repulsion Since there is a risk of repulsion and scattering, it is necessary to preheat the powder material of the powder layer to prevent scattering. The preheated powder material has a reduced electrical resistance, is not charged to conduct the charge generated by the interaction with the electron beam, and the above-mentioned scattering does not occur. Therefore, in an apparatus for producing 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) of the electron beam and the beam scanning speed (for example, Patent Document 3).

JP 2011-506761 gazette JP, 2015-30872, A Japanese Patent Publication No. 2010-526694

Measurement and Control, Vol. 54, No. 6, June 2015 (P. 399-404)

  However, in the method of performing preheating by changing parameters such as the beam output of the electron beam as in Patent Document 3, when the size of the three-dimensional structure to be manufactured is large and the surface area of the powder layer is large, Due to the large heat loss due to the heat radiation, the preheating may be insufficient. This is because it is not possible to use a high energy electron beam to melt, solidify or sinter the powder material in the preheating stage, and there is an upper limit to the beam output, so the heat loss due to heat radiation is covered by adjusting the beam output. Because it is difficult to do.

  The present application has been made to solve the problems as described above, and provides a three-dimensional shaping apparatus capable of easily performing sufficient preheating of a powder material even when producing a large three-dimensional structure. It is a thing.

  The three-dimensional modeling apparatus disclosed in the present application is a three-dimensional modeling apparatus that manufactures a three-dimensional model by repeating a process of selectively solidifying a powder material that forms a powder layer by irradiation with an electron beam. An electron beam irradiation means for irradiating the material with an electron beam, a modeling region forming portion provided on a surface facing the electron beam irradiation means, and in which the powder material is spread to form a powder layer, and the powder layer in a heated state And a shield member which covers the shaping region forming portion and heats up by heat radiation from the preheating member, and the powder material transfers heat from the preheating member and It is preheated by the heat radiation from the shield member which was heated.

  According to the three-dimensional shaping apparatus disclosed in the present application, sufficient preheating of the powder material can be easily performed even in the case of producing a large three-dimensional figure.

FIG. 1 is a schematic view showing a three-dimensional shaping apparatus in Embodiment 1. FIG. 1 is a perspective view showing an outline of a radiation shield according to a first embodiment. 5 is a plan view showing a frame of the radiation shield according to Embodiment 1. FIG. FIG. 5 is a view showing a metal plate that constitutes a side surface portion of the radiation shield according to the first embodiment. FIG. 6 is a view for explaining the operation of the three-dimensional shaping apparatus in Embodiment 1. FIG. 10 is a perspective view of a radiation shield according to a modification of the first embodiment. FIG. 8 is a perspective view showing an outline of a radiation shield according to Embodiment 2; FIG. 10 is a perspective view showing an outline of a radiation shield according to Embodiment 3. FIG. 16 is a schematic view showing a three-dimensional shaping apparatus in a fourth embodiment. FIG. 18 is a schematic view showing a three-dimensional shaping apparatus in a fifth embodiment.

Embodiment 1
The first embodiment will be described below based on FIGS. 1 to 5. FIG. 1 is a schematic view showing a three-dimensional shaping apparatus in the first embodiment. In the three-dimensional modeling apparatus 100, an electron gun 2 for irradiating the electron beam EB1 downward, ie, an electron beam irradiation means is provided in the upper part of the vacuum chamber 1, and the ceiling surface 1b of the vacuum chamber 1 The opposite surface is provided with an opening (not shown) for passing the electron beam EB1. The electron gun 2 faces the modeling area forming unit 3 formed on the floor surface 1 a of the vacuum chamber 1, and can irradiate the inside of the modeling area forming unit 3 with the electron beam EB 1. The modeling region forming unit 3 has, for example, a square horizontal cross section of 90 mm × 90 mm, the inside thereof is a modeling region of a three-dimensional model, and the 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 when it is irradiated with the electron beam EB1 from the electron gun 2, it is melted and solidified or sintered to form 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 melt solidified or sintered by irradiation of electron beam. What is necessary. The powder layer 7 is formed by supplying a predetermined amount of powder material while moving the upper part and the periphery of the shaping region forming portion 3 and the powder material supplying portion 93 spreading the powder material inside the shaping region forming portion 3 in layers. It is The powder material supplied by the powder material supply unit 93 is accommodated in a powder material accommodation unit 92 which is, for example, a rectangular parallelepiped box. The powder material storage unit 92 drops the powder material when the powder material supply unit comes down, and supplies the powder material to the powder material supply unit 93. It is sufficient that the electron beam EB1 can be irradiated from the electron gun 2 to the modeling area forming unit 3, so the position at which the modeling area forming unit 3 is provided is not limited to the floor surface 1a. Good. For example, a work bench (not shown) may be installed on the floor surface 1a, and the modeling region forming unit 3 may be provided on the upper surface thereof.

  At the bottom of the modeling area forming unit 3, a modeling table 5 which can slide up and down is provided. The modeling table 5 is moved up and down by a lifting mechanism 6 provided below, and by operating the lifting mechanism 6, the depth of the modeling area forming unit 3 can be adjusted. FIG. 1 shows a state in which the shaping table 5 is lowered from the floor surface 1 a by two layers of the powder layer 7, and 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 to have a thickness of about several tens of μm.

  The pedestal 4 in the heated state is embedded in the first powder layer 7. The pedestal 4 serves as a base portion of the three-dimensional structure and also 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 the irradiation of the electron beam, but it is preferable that the heat capacity is large.

  Above the modeling area formation part 3, the radiation shield 10 which is supported by the support jig 91 at a predetermined height and covers the whole modeling area formation part 3 is provided. The radiation shield 10 has a trapezoidal shape that widens in the side view in the side view, that is, as it approaches the modeling area forming portion 3, and the cross-sectional area in the direction parallel to the floor surface 1a increases in the lower side. Further, the height at which the radiation shield 10 is installed is not particularly limited as long as the movement of the powder material supply unit 93 is not hindered. The radiation shield 10 is provided at the upper end with an opening 10c facing the electron gun 2 and at the lower end with an opening 10b facing the shaping region forming part 3 so that the hollow portion 10a through which the electron beam EB1 passes is from the upper end to the lower end The radiation shield 10 does not prevent the irradiation of the electron beam EB1 from the electron gun 2 to the shaping region forming portion 3 because it is formed inside.

FIG. 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. The radiation shield 10 is disposed at the upper end of the radiation shield 10 as shown in FIG. 2, and the first side surface portion 13 and the second side surface portion 14 are provided on each side of the rectangular frame 12 which constitutes the upper surface 11 of the radiation shield 10. Of the first side face portion 13 and the second side face portion 14 are attached to the frame 12 by screws 19 respectively.
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 shaping region forming portion 3, and is attached to the upper surface 11 at a right angle. The second side portion 14 extends downward from the upper surface 11 and is attached at an angle of 45 ° to the upper surface 11. As described above, since the second side face portion 14 forms an angle of 45 ° with 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, although the second side face portion 14 forms an angle of 45 ° with the upper surface 11, the second side face portion 14 may have a wide angle as the radiation shield 10 extends downward. The angle formed with respect to the upper surface 11 is not limited to 45 ° and may be an acute angle. Also, although the first side surface portion 13 is attached at a right angle to the upper surface 11, even if the first side surface portion 13 is attached at an acute angle to the upper surface 11 as well as the second side surface portion 14. Good.

As shown in FIG. 3, the frame 12 has an opening 10c of, for example, 38 mm × 38 mm in size, formed substantially at the center. Further, in the frame 12, bent portions 12b are provided at both left and right ends in the drawing. The bent portion 12 b 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. Further, two screw holes 12c through which the screws 19 pass are formed in the bent portion 12b.
The first side face portion 13 is formed by superposing the metal plates 131 shown in FIG. 4A in triple layers, and screw holes (not shown) formed in the screw holes 13 c of the metal plates 131 and the side portions of the frame 12. Are attached to the frame 12 by means of screws 19 which pass through. The metal plate 131 has a trapezoidal shape in a plan view, and has, for example, an upper side 13a of 47 mm in length, and an oblique side 13b of, for example, 74 mm in length that forms an angle of 135 ° with the upper side 13a. Here, since the upper side 13 a is parallel to the upper surface 11 of the radiation shield 10, the oblique side 13 b makes an angle of 45 ° with the upper surface 11 downward. The second side face portion 14 is formed by overlapping the metal plates 141 shown in FIG. 4B in triples, and using 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 is rectangular in a plan view, and has, for example, a short side 14a of 54 mm in length and a long side 14b of, for example, 74 mm in length. 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, an interval 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. In addition, the number of sheets and the space | interval of the metal plate 131 and the metal plate 141 to overlap are not restricted above, What is necessary is just to mutually space the some metal plate 131 and the metal plate 141, and to overlap.

  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. After the powder material is spread in the formation region forming portion 3 to form the first powder layer 7, the pedestal 4 is embedded in the upper surface of the first powder layer 7. As shown in FIG. 5A, when the pedestal 4 is heated by irradiating the pedestal 4 with the preheating electron beam EB2, which is an electron beam having a smaller energy density than the electron beam EB1 for melting and solidifying the powder material. The heat radiation H2 is generated above the pedestal 4, and the heat transfer H1 consisting of heat conduction and heat radiation is generated at the sides and below the pedestal 4. Since the radiation shield 10 covers the whole of the modeling area forming portion 3 as described above, most of the heat radiation H2 upward is recovered and heated. The heat transfer H1 raises the temperature of the powder layer 7 and the shaping region forming unit 3 surface.

  When the surface of the radiation shield 10 and the shaping region forming portion 3 is heated, the heat radiation H2 to the first powder layer 7 and the pedestal 4 is generated from the radiation shield 10 which is heated as shown in FIG. . In addition, heat transfer H1 to the powder layer 7 and the pedestal 4 of the first layer occurs from the surface of the modeling region forming portion 3 whose temperature has been raised. The temperature of the first powder layer 7 is raised by heat transfer H 1 from the pedestal 4, heat transfer H 1 from the surface of the shaping region forming portion 3, and heat radiation H 2 from the radiation shield 10.

  After the temperature rise of the first powder layer 7, as shown in FIG. 5C, the shaping table 5 and the first powder layer 7 are lowered by the lifting mechanism 6 to form a space, and in the case of the first layer Similarly to the above, the second powder layer 7 is formed. When the second powder layer 7 is formed, the first powder layer 7, the surface of the shaping region forming portion 3, and the radiation shield 10 are in a sufficiently heated state, and thus 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 powder layer 7 of the second layer is preheated to such a temperature that scattering of the powder material does not occur by the heat transfer H1 and the heat radiation H2 even when the preheating electron beam EB2 is irradiated. Thereafter, as shown in FIG. 5 (d), the second powder layer 7 is irradiated with the preheating electron beam EB2 to melt and solidify the powder material. The eye powder layer 7 is preheated. 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, in addition to the irradiation of the preheating electron beam EB2, the second powder layer 7 receives the heat transfer H1 from the surface of the pedestal 4, the first powder layer 7 and the shaping region forming portion 3, and the radiation shield 10 It is also preheated by the heat radiation H2.

  After preheating of 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 to melt and solidify the powder material in the desired range and solidify. Generate 8 After the formation of the solidified body 8, the forming table 5 is further lowered, and the formation of the third and subsequent powder layers 7, the preheating, and the generation of the solidified body are repeated in the same manner as in the second layer.

  In the first embodiment, the pedestal 4 embedded in the first powder layer 7 is heated by irradiation with the preheating electron beam EB2 emitted from the electron gun 2. Is not limited to this. For example, you may embed the base 4 of the state which heated up previously with the heater etc. in the powder layer 7 of 1st layer. The point is that the heated pedestal 4 is embedded in the first powder layer 7 continuously for a predetermined 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 heat radiation H2 from the radiation shield 10 whose temperature has been increased and the temperature H1.

  As described above, the radiation shield 10 is configured by overlapping the first side surface portion 13 and the second side surface portion 14 with the three metal plates 131 and the metal plates 141 at an interval, respectively. The thermal resistance between the respective metal plates 131 and between the respective metal plates 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 portion 3 is quicker than when the metal plate 131 and the metal plate 141 are stacked without leaving a space. In addition, the heat capacity of the first side surface portion 13 and the second side surface portion 14 becomes larger than the case where it is configured by only one metal plate, and the temperature of the radiation shield 10 is maintained at high temperature for a long time.

  In order to investigate the contribution of the radiation shield 10 to the preheating of the powder layer 7, the temperature rising time and the temperature rising rate of the pedestal 4 without and with the radiation shield 10 were measured. The measurement is performed in a state in which the pedestal 4 is embedded in the upper surface of the first powder layer 7 formed in the interior of the modeling area forming portion 3 as in FIG. 5A, and the sheath type attached to the lower portion of the pedestal 4 The temperature at the mounting position of the thermocouple was taken as the temperature of the pedestal 4. When the radiation shield 10 is not provided, the radiation shield 10 is provided while the time required to raise the temperature of the pedestal 4 to 850 ° C. is 1200 seconds (heating rate: 0.69 ° C./second). In the case, it was 640 seconds (heating rate: 1.21 ° C./sec). The reason why the temperature rise time and the temperature rise rate are different in this way is considered that the energy which is a heat loss due to the heat radiation upward without the radiation shield 10 is recovered and reused by the radiation shield 10 .

  In addition, the surface temperature of the center of the base 4 and the end of the base 4 are recorded until the temperature of the base 4 reaches 850 ° C., and the temperature difference between the center and the end is measured. The maximum temperature difference in the case where the radiation shield 10 was not provided was 250 ° C., while the maximum temperature difference in the case where the radiation shield 10 was provided was 160 ° C., and the temperature unevenness was reduced by 90 ° C. It is considered that the effect by the recovery and reuse of the thermal radiation H2 by the radiation shield 10 is large at the end where the loss due to the thermal radiation H2 is larger than that at the central portion, and the temperature unevenness is reduced.

  Although the contribution of the radiation shield 10 in the case of 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 whole of the modeling region forming portion 3 where the powder layer 7 is formed, the heat radiation H 2 emitted upward from the surface of the pedestal 4 and the modeling region forming portion 3 heated up from the surface of the powder layer 7 is The temperature is raised by the collected heat radiation H2 while generating the heat radiation H2 to the powder layer 7, thereby contributing to the preheating of the powder layer 7 and the 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 portion 3 and the powder layer 7 is large, the heat radiation to the upper side is also large, so the contribution of the radiation shield 10 is considered to be large.

The heat radiation of the shaping region forming portion 3 and the powder layer 7 is emitted in all directions, and there is also the heat radiation which leaks from the space between the radiation shield 10. It is preferable to arrange it close to As described above, the height of the radiation shield 10 needs to be in a range that does not impede the movement of the powder material supply unit 93. For example, instead of the support jig 91, the radiation shield 10 can be adjusted by height adjustment. May be supported. In this case, when forming the powder layer 7, the radiation shield 10 is disposed high to prevent movement of the powder material supply unit 93, and in the other cases, the radiation shield 10 is arranged as low as possible. By bringing it closer to 3, more heat radiation H2 can be recovered.
Further, since the heat radiation H2 from the radiation shield 10 depends on the heat radiation of the surface, the lower surface of the metal plate 131 and the metal plate 141, that is, the surface facing the shaping region forming portion 3 is subjected to anodizing treatment to be a radiation shield. The heat dissipation of 10 may be enhanced.

  According to Embodiment 1, even in the case of producing a large three-dimensional structure, sufficient preheating of the powder material can be easily performed. More specifically, heat radiation emitted upward from the surface of the pedestal heated by the preheating electron beam and the surface of the modeling region forming portion heated by heat transfer from the pedestal is covered by the radiation shield covering the entire modeling region forming portion Even when there is a possibility that the heat loss due to the heat radiation to the upper side may become large as in the case of manufacturing a large three-dimensional structure, in order to recover and reuse it, the temperature drop of the powder layer due to the heat radiation is suppressed. , Sufficient preheating of the powder layer is easy.

  In addition, in the preheating of the second and subsequent powder layers, the energy density of the preheating electron beam can be made smaller than that of the prior art. More specifically, in addition to the irradiation of the preheating electron beam, the powder layers of the second and subsequent layers are heat transfer from the pedestal, the powder layers before the first layer, and the surface of the shaping region forming portion, and heat from the radiation shield. Since energy is also preheated by radiation, the energy density of the preheating electron beam can be made smaller than before.

  In addition, sufficient preheating of the powder layer can be performed more stably. More specifically, the heat radiation from the end where the loss due to heat radiation is larger is recovered by a radiation shield and reused to reduce temperature unevenness between the center and the end, so that the powder layer sufficiently Preheating can be performed more stably. In particular, the larger the three-dimensional object to be manufactured, the larger the temperature unevenness, and the possibility that sufficient preheating is not achieved at the end increases. However, by reducing the temperature unevenness as described above, sufficient preheating is more stable. 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 portion and the second side portion is increased by stacking the metal plates constituting the first side portion and the second side portion of the radiation shield in a triple layer. Therefore, the high temperature state of the heated radiation shield can be maintained, and the time which contributes to the preheating of the powder layer by the heat radiation can be made longer.

  In addition, 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 each other at an interval, so that the metal plates are in contact rather than being brought into contact with each other. Because the thermal resistance between the two is increased, the temperature rising rate of the metal plate closest to the modeling area formation part is faster, the heat radiation from the radiation shield starts earlier, and the temperature drop suppression effect of the powder layer is You can get it earlier.

  In addition, the installation space of the radiation shield can be reduced. More specifically, the second side surface portion is attached at an angle of 45 ° with respect to the upper surface of the radiation shield, whereby the radiation shield has a shape which spreads downward, thereby forming the shaped region forming portion. As the cross-sectional area in the direction parallel to the floor surface of the vacuum chamber is larger the closer it is to the lower side, the cross-sectional area necessary to cover the entire modeling area forming portion is secured while the top of the radiation shield is reduced. Installation space can be reduced.

  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 in a flat plate 121 covering the entire modeling region forming portion 3. The flat plate 121 contributes to the preheating of the powder layer 7 by recovering the heat radiation from the pedestal 4 and raising the temperature, and generating the heat radiation downward after the temperature rise. Although the radiation shield 101 has a side surface, the heat radiation from the pedestal 4 and the like is easily leaked compared to the radiation shield 10 of the first embodiment, but the configuration is very simple.

Second Embodiment
The second embodiment will be described below based on FIG. The same or corresponding portions as in FIGS. 1 to 4 are denoted by the same reference numerals, and the description thereof will be omitted. The second embodiment differs from the first embodiment in the shape of the radiation shield. FIG. 7 is a perspective view showing an outline of a radiation shield according to the second embodiment. The radiation shield 20 arranges rectangular frames 22A to 22C having mutually different sizes in parallel, and screws the first side component 23A to 23C and the second side component 24A to 24C with respect to each frame. The first side surface portion 23 and the second side surface portion 24 are configured by being attached with no gap by 29. Inside the radiation shield 20, a hollow portion (not shown) is formed from the upper end to the lower end.

The smallest frame 22 </ b> A of the frames 22 </ b> A to 22 </ b> C is disposed at the upper end of the radiation shield 20 and constitutes the upper surface 21 of the radiation shield 20. A first side component 23A and a second side component 24A are attached to the frame 22A. The first side component 23A extends downward from the upper surface 21 of the radiation shield 20, that is, in the direction of the shaping region forming portion 3, and is attached to the upper surface 21 at a right angle. The second side component 24 A extends downward from the top surface 21 and is attached at an angle of 30 ° to the top surface 21.
The middle sized frame 22B is disposed below the frame 22A by the height of the first side component 23A, and the first side component 23B and the second side component 24B are attached. The first side component 23B is attached at a right angle to the frame 22B, and the second side component 24B is attached at an angle of 45 ° to the frame 22B. Here, the frame 22B is disposed parallel to the frame 22A and is also parallel to the upper surface 21. Therefore, the first side component 23B is also perpendicular to the upper surface 21, and the second side component 24B is The top surface 21 also has a 45 ° angle.
The largest frame 22C is disposed below the frame 22B by the height of the first side component 23B, and the first side component 23C and the second side component 24C are attached. The first side component 23C is attached at a right angle to the frame 22C, and the second side component 24C is attached at an angle of 60 ° to the frame 22C. Here, the frame 22C is disposed parallel to the frame 22A and is parallel to the upper surface 21. Therefore, the first side component 23C is also perpendicular to the upper surface 21, and the second side component 24C is The top surface 21 also has an angle of 60 °.
As described above, in the second embodiment, the angles formed by the second side surface component members 24A to 24C with the upper surface 21 gradually increase in the downward direction to 30 °, 45 °, and 60 °.

  In order to attach the second side component members 24A to 24C at an acute angle to the frames 22A to 22C, a bent portion is provided as in the frame 12 of the first embodiment, and the upper surface of the bent portion bent downward. Each second side component 24A-24C should just be attached to. Further, as in the first embodiment, the first side surface component members 23A to 23C and the second side surface component members 24A to 24C are formed of three metal plates overlapped at an interval of 2 mm. There is.

In order to investigate the contribution of the radiation shield 20 to the preheating of the powder layer 7, the temperature rising time and the temperature rising rate of the pedestal 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 (heating rate: 1.31 ° C./sec), and the radiation shield 10 of the first embodiment is provided. A further reduction of 30 seconds was confirmed. As for the temperature non-uniformity, the maximum temperature difference was 75 ° C., and it was confirmed that the temperature non-uniformity was further reduced by 85 ° C. than when the radiation shield 10 was provided. This is because the angle between the second side component 24C closest to the modeling area forming portion 3 and the upper surface 21 of the radiation shield 20 is 60 °, and the second side portion 14 and the upper surface 11 of the radiation shield 10 are Is considered to be larger than 45 °, which is an angle formed by That is, as the angle 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 It is considered that the heating rate is further increased because more recovery and reuse can be performed. Further, it is considered that the heat radiation H2 leaking to the side is more likely to be emitted from the end rather than from the center of the pedestal 4, so that the temperature decrease at the end is further reduced and the temperature unevenness is also reduced. Conceivable.
In addition, since the radiation shield 20 covers the whole modeling area | region formation part 3 in which the powder layer 7 is formed, it is thought that the same effect is acquired also when preheating the powder layer 7. FIG.
The other aspects are the same as in the second embodiment, and thus the description thereof is omitted.

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

  Moreover, while raising the temperature rising rate at the time of preheating of the powder layer 7 further, temperature irregularity can be further reduced. More specifically, the angle formed by the second side component with respect to the upper surface of the radiation shield is gradually increased, and the heat radiation leaking from between the shaping region forming portion and the radiation shield is further reduced. In particular, the heat radiation from the end portion can be recovered and reused more, and the temperature rising rate can be further increased, and the temperature unevenness can be further reduced.

Third Embodiment
The third embodiment will be described below based on FIG. The same or corresponding portions as in FIGS. 1 to 4 are denoted by the same reference numerals, and the description thereof will be omitted. The third embodiment differs from the first and second embodiments in the shape of the radiation shield. FIG. 8 is a perspective view showing an outline of a radiation shield according to the third embodiment. The radiation shield 30 has the side portions 33 forming a paraboloid as a whole by arranging the frames 32A to 32C having mutually different sizes in parallel with one another and attaching the plurality of side surface members 33A without a gap with the screws 39. It is a thing. Inside the radiation shield 30, a hollow portion (not shown) is formed from the upper end to the lower end.

  The smallest frame 32 </ b> A of the frames 32 </ b> A to 32 </ b> C is disposed at the upper end of the radiation shield 30 and constitutes the upper surface 31 of the radiation shield 30. A side surface component 33A is attached to the frame 32A, and the side component 33A extends downward from the upper surface 31 of the radiation shield 30, that is, in the direction of the shaping region forming portion 3. The middle size frame 32B is disposed below the frame 32A by the height of the side component 33A, and the side component 33B is attached. The largest frame 32C is disposed below the frame 32B by the height of the side component 33B, and the side component 33C is attached. Each of the side surface component members 33A to 33C is bent so as to form a paraboloid as a whole of the side surface portion 33, and is formed of three metal plates overlapped at an interval of 2 mm. Since the side surface members 33A to 33C are attached in such a manner that the lower surface of the side surface portion 33, that is, the surface facing the shaping region forming portion 3 constitutes a paraboloid, any side surface members 33A to 33C are attached to the upper surface 31 It has an acute angle, and the angle is larger toward the bottom. Therefore, the angle between the side surface component 33B is larger than that of the side surface component 33A, and the angle of the side surface component 33C is larger than the side surface component 33B. The other aspects are the same as in the second embodiment, and thus the description thereof is omitted.

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

Fourth Embodiment
The fourth embodiment will be described below based on FIG. The same or corresponding portions as in FIGS. 1 to 8 are denoted by the same reference numerals, and the description thereof will be omitted. FIG. 9 is a schematic view showing a three-dimensional shaping apparatus in a fourth embodiment. In the three-dimensional modeling apparatus 200, the radiation shield 40 is provided at the upper end with an opening 40c facing the electron gun 2 and at the lower end with an opening 40b facing the shaping region forming part 3 and through which the electron beam EB1 passes The portion 40a is formed inside from the upper end to the lower end. Similar to the radiation shield 10 of the first embodiment, the radiation shield 40 has a trapezoidal shape that narrows in the upper side in a side view, that is, the further away from the shaping region forming portion 3, and cuts in a direction parallel to the floor surface 1 a in the upper direction. The area is getting smaller. The height of the opening 40b at the lower end is the same as the opening 10b of the radiation shield 10. However, the side 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, it is considered as an example that the distance D2 between the opening 40c at the upper end and the ceiling surface 1b of the vacuum chamber 1 is equal to or less than the distance D1 between the opening 40b at the lower end and the powder layer 7 Be The smaller the distance D2 between the opening 40c and the ceiling 1b surface of the vacuum chamber 1 is, the higher the opening 40c is and the smaller the cross-sectional area of the opening 40c. Therefore, the distance D2 is preferably as small as possible. The other aspects are the same as in the first embodiment, and thus the description thereof is omitted.

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

  Also, by extending the side surface upward in the trapezoidal radiation shield whose cross-sectional area decreases toward the upper side, it is provided on the opposite side to the modeling region forming portion while keeping the height of the opening on the modeling region forming portion side low. The height of the opening is increased, and the cross-sectional area of the opening opposite to the shaping region forming portion is further reduced. For this reason, while maintaining the amount of heat radiation collected from the modeling area, it is suppressed that the collected heat radiation leaks from the opening on the opposite side to the modeling area forming part, and the powder layer can be preheated more efficiently. It can be carried out.

Embodiment 5
The fifth embodiment will be described below based on FIG. The same or corresponding portions as in FIGS. 1 to 9 are denoted by the same reference numerals, and the description thereof will be omitted. In the fifth embodiment, the side surface of the radiation shield is extended further upward than the fourth embodiment. FIG. 10 is a schematic view showing a three-dimensional shaping apparatus in the fifth embodiment. In the three-dimensional modeling apparatus 300, the radiation shield 50 is provided at the upper end with an opening 50c facing the electron gun 2 and at the lower end with an opening 50b facing the shaping region forming part 3 and through which the electron beam EB1 passes The portion 50a is formed inside from the upper end to the lower end. Similar to the radiation shield 10 of the first embodiment, the radiation shield 50 has a trapezoidal shape that narrows in the upper side in the side view, that is, the further away from the shaping region forming portion 3, and cuts in a direction parallel to the floor surface 1 a in the upper direction. The area is getting smaller. Further, the side surface of the radiation shield 50 extends above the radiation shield 10, the opening 50c at the upper end abuts on the ceiling surface 1b of the vacuum chamber 1, and the gap between the opening 50c and the ceiling surface 1b is closed. There is. The other aspects are the same as in the first embodiment, and thus the description thereof is omitted.

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

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

Although the present application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments apply to the specific embodiments. The present invention is not limited to the above, and can be applied to the embodiments alone or in various combinations.
Accordingly, numerous modifications not illustrated are contemplated within the scope of the technology disclosed herein. For example, when deforming at least one component, adding or omitting it, it is further included that at least one component is extracted and combined with a component of another embodiment.

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

Claims (9)

A three-dimensional shaping apparatus for producing a three-dimensional structure by repeating a process of selectively solidifying a powder material forming a powder layer by irradiation of an electron beam,
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, in which a powder layer of the powder material is formed;
A preheating member which is embedded in the powder layer in a heated state and which preheats the powder material by heat transfer;
And a shield member which covers the modeling area forming portion and which is heated by heat radiation from the preheating member.
The three-dimensional shaping apparatus characterized in that the powder material is preheated by heat transfer from the preheating member and heat radiation from the shield member that has been heated.   The three-dimensional shaping apparatus according to claim 1, wherein the temperature of the preheating member is raised by the 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 the surface provided with the modeling area forming section as closer to the modeling area forming section.   The tertiary according to any one of claims 1 to 3, wherein the shield member comprises a side surface portion extending in the direction of the shaped region forming portion and forming an acute angle with the upper surface of the shield member. Original modeling device.   The three-dimensional modeling apparatus according to claim 4, wherein the side surface portion is a plurality of plate-like members overlapped at intervals.   The three-dimensional modeling apparatus according to claim 5, wherein the plate-like members are stacked in three layers.   The three-dimensional 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 portion.   The three-dimensional modeling apparatus according to any one of claims 4 to 7, wherein in the side surface section, a surface opposite to the modeling region forming section is a paraboloid.   The shield member according to any one of claims 4 to 8, wherein an opening provided on the opposite side to the modeling area forming section is in contact with a surface facing the modeling area forming section. Three-dimensional modeling device as described.

Images