Three-dimensional modeling device

Abstract

To obtain an electron gun that shortens a time for manufacturing a three-dimensional model from a metal powder material.SOLUTION: An electron gun includes a photocathode 18, a laser oscillator 11 and a collimation lens 12, which are a laser optical system for irradiation with a laser beam 20 for exciting the surface of the photocathode 18, and a DLP chip 13 positioned between the laser optical system and the photocathode 18 and adjusting the shape and amount of the laser beam 20 incident on the surface of the photocathode 18.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an electron gun and a three-dimensional modeling apparatus for producing a three-dimensional object. [Background technology]

[0002] An apparatus has been proposed that irradiates a metal powder material with an electron beam to melt the metal powder material and then solidify it, thereby stacking multiple layers using the metal powder material to manufacture a three-dimensional object (see, for example, Patent Document 1). This apparatus has a means that can repeat multiple times the steps of supplying the metal powder material to an area where the three-dimensional object is to be formed, and selectively irradiating the supplied metal powder material with an electron beam to melt the metal powder material and then solidify it.

[0003] When a three-dimensional modeling device irradiates a metal powder material with an electron beam, the charged metal powder material scatters due to repulsion caused by Coulomb force between the charged metal powder materials. Therefore, when irradiating a metal powder material with an electron beam, it is essential to take measures to prevent the metal powder material from becoming charged.

[0004] The method disclosed in Patent Document 1 includes a step of preheating the metal powder material. In the preheating step, the metal powder material is irradiated with a defocused electron beam to prevent localized charging and thereby heat the metal powder material to a high temperature in advance to reduce the electrical resistance of the metal powder material. This prevents the metal powder material from being charged when the metal powder material is subsequently irradiated with an electron beam for solidifying the metal powder material. Patent Documents 2 and 3 also disclose methods for preventing the scattering of the metal powder material by preheating.

[0005] Patent Document 4 discloses an electron gun that uses a photocathode as an electron source. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5108884 [Patent Document 2] International Publication No. 2019 / 088114 [Patent Document 3] International Publication No. 2019 / 049832 [Patent Document 4] Patent No. 6466020 Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional three-dimensional modeling devices have a problem that, if the temperature of the modeling surface is low before the preheating process in which the metal powder material is uniformly heated before being irradiated with a modeling beam, the metal powder material scatters due to charging. In addition, conventional three-dimensional modeling devices require time to irradiate the preheating beam, which does not directly contribute to forming a model, and the process of irradiating the preheating beam is repeated for the number of modeling layers, which lengthens the modeling time and reduces production capacity.

[0008] The essence of the problem is that the voltage and current applied to the electron lens for emitting the focused electron beam for modeling are extremely different from the voltage and current applied to the electron lens for emitting the defocused electron beam for preheating, and the time required for switching the voltage and current is long, so that in order to minimize the number of times the voltage and current are switched, the beam irradiation process is divided into a process of irradiating the electron beam for modeling and a process of irradiating the electron beam for preheating. Ideally, the beam for modeling is irradiated simultaneously with the completion of the supply of the metal powder material to the modeling area, thereby increasing the proportion of the irradiation time of the beam for modeling in the modeling time, and thereby improving production capacity. The above modeling time is the time required for all processes required for modeling, from evacuation to completion of cooling.

[0009] The present disclosure has been made in consideration of the above, and aims to provide an electron gun that shortens the time required to manufacture a three-dimensional object from a metal powder material. [Means for solving the problem]

[0010] In order to solve the above problems and achieve the object, the present disclosure relates to 3D printing equipment The present invention relates to a laser light source that includes a photocathode, a laser optical system that irradiates a laser beam for exciting the surface of the photocathode, and an adjustment device that is located between the laser optical system and the photocathode and adjusts the light shape and light amount of the laser beam incident on the surface of the photocathode. The three-dimensional printing apparatus has an electron gun and irradiates a metal powder material with an electron beam based on electrons extracted from a photocathode to manufacture a three-dimensional object. The three-dimensional printing apparatus according to the present disclosure irradiates the metal powder material with a printing beam, which is an electron beam that is irradiated to the metal powder material in accordance with the shape of the object, after a period of 1 second or less but 10 nanoseconds or more after irradiation with a preheating beam that sinters the metal powder material, and irradiates the metal powder material with the preheating beam and the printing beam alternately such that the preheating beam is irradiated after a period of 1 second or less but 1 femtosecond or more after irradiation with the printing beam depending on the switching speed of the laser light source. Effect of the Invention

[0011] The electron gun according to the present disclosure has an effect of shortening the time required to manufacture a three-dimensional object from a metal powder material. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing an outline of a configuration of a three-dimensional modeling apparatus according to a first embodiment; [Diagram 2] A schematic diagram showing the base plate being irradiated with an electron beam as viewed from the electron gun chamber side. [Diagram 3] FIG. 1 is a diagram for explaining a conventional beam irradiation pattern. [Figure 4] FIG. 1 is a diagram showing a change in output with respect to time of a beam irradiation pattern according to the first embodiment. [Diagram 5] FIG. 1 is a side view showing an outline of a DLP chip and a photocathode in the first embodiment when a preheating laser light for generating a preheat beam is irradiated onto the photocathode; [Figure 6] FIG. 1 is a front view showing an outline of a DLP chip and a photocathode in the first embodiment when a preheating laser light for generating a preheat beam is irradiated onto the photocathode; [Figure 7] FIG. 1 is a side view showing an outline of a DLP chip and a photocathode in the first embodiment when a laser beam for shaping that generates a shaping beam is irradiated onto the photocathode; [Figure 8]FIG. 1 is a front view showing an outline of a DLP chip and a photocathode in the first embodiment when a laser beam for shaping that generates a shaping beam is irradiated onto the photocathode; [Figure 9] FIG. 1 is a diagram for explaining a preheating laser beam and a modeling laser beam irradiated to a photocathode in the first embodiment; [Figure 10] FIG. 13 is a diagram showing how a preheating beam and a modeling beam are switched and irradiated onto a modeling area. [Figure 11] FIG. 13 is a diagram showing an outline of the configuration of a three-dimensional modeling apparatus according to a second embodiment; [Figure 12] FIG. 13 is a diagram showing an outline of a configuration of a three-dimensional modeling apparatus according to a third embodiment; [Figure 13] FIG. 13 is a diagram showing an outline of a configuration of a three-dimensional modeling apparatus according to a fourth embodiment; [Figure 14] FIG. 13 is a diagram showing an outline of a configuration of a three-dimensional modeling apparatus according to a fifth embodiment; [Figure 15] FIG. 1 is a diagram showing a processor in the case where a control device included in the three-dimensional printing apparatus according to the first embodiment is realized by the processor; [Figure 16] FIG. 1 is a diagram showing a processing circuit in the case where a control device included in the three-dimensional printing apparatus according to the first embodiment is realized by the processing circuit; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electron gun and a three-dimensional modeling apparatus according to an embodiment will be described in detail below with reference to the drawings.

[0014] Embodiment 1 Fig. 1 is a diagram showing an outline of the configuration of a three-dimensional modeling apparatus 1 according to the first embodiment. The three-dimensional modeling apparatus 1 is an apparatus that irradiates a metal powder material with an electron beam 10 to manufacture a three-dimensional object, and has a laser oscillator 11 that generates a laser beam 20 for generating the electron beam 10 and outputs the laser beam 20. The electron beam 10 and the laser beam 20 are also shown in Fig. 1. In the drawing, the electron beam 10 is indicated by a dashed line, and the laser beam 20 is indicated by a broken line.

[0015] The three-dimensional modeling apparatus 1 further includes a collimation lens 12 that collimates the laser light 20 output from the laser oscillator 11, and a DLP (Digital Light Processing) chip 13 that changes the traveling direction of the laser light 20 collimated by the collimation lens 12. The three-dimensional modeling apparatus 1 further includes a focus lens 14, a collector 15, and an electron gun chamber 121 that generates an electron beam 10 based on the laser light 20. The electron gun chamber 121 includes a beam splitter 16 that splits the laser light 20 into two laser beams 20. The focus lens 14 causes the laser light 20, the traveling direction of which has been changed by the DLP chip 13, to travel to the beam splitter 16.

[0016] The electron gun chamber 121 further includes a first reflector 17A, a second reflector 17B, and a photocathode 18 that generates an electron beam 10 based on a laser beam 20. The photocathode 18 is an electron source. The beam splitter 16 causes one of the two split laser beams 20 to travel to the first reflector 17A, and causes the other of the two split laser beams 20 to travel to the second reflector 17B. Each of the first reflector 17A and the second reflector 17B reflects the traveling laser beam 20 and causes it to travel to the surface of the photocathode 18.

[0017] In the first embodiment, the laser oscillator 11 and the collimation lens 12 constitute a laser optical system that irradiates laser light 20 for exciting the surface of the photocathode 18. The DLP chip 13 is an adjustment device located between the laser optical system and the photocathode 18, and has a function of adjusting the light shape and light amount of the laser light 20 incident on the surface of the photocathode 18. The photocathode 18, the laser optical system, and the DLP chip 13 constitute an electron gun. The electron beam 10 is a beam extracted from the photocathode 18. More specifically, the electron beam 10 is a beam extracted from the surface of the photocathode 18.

[0018] The electron gun chamber 121 further includes an anode 19 that accelerates the traveling speed of the electron beam 10 generated in the photocathode 18. In other words, the anode 19 accelerates the traveling speed of the electrons. The electron gun chamber 121 further includes a deflection coil 110 that deflects the electron beam 10 whose traveling speed has been accelerated by the anode 19.

[0019] The inside of the three-dimensional modeling device 1 is at atmospheric pressure of 1×10 -2 Pa to 1×10 -4 The three-dimensional printing apparatus 1 further includes a modeling chamber 119 that is decompressed to any pressure up to 1×10 Pa. A model is manufactured inside the modeling chamber 119. -2 Pa to 1×10 -5 It further comprises a vacuum pump for reducing the pressure to any pressure up to 100 Pa. The vacuum pump is not shown.

[0020] The building chamber 119 has a base plate 114 to which metal powder material, which is the material for the object to be built, is supplied, and a squeegee 112 to spread the metal powder material evenly on the base plate 114. The upper surface of the metal powder material that is supplied onto the base plate 114 and then spread evenly by the squeegee 112 is a building surface 118. The building surface 118 is the surface on which a model will be formed, the surface of a model being manufactured, or the surface of a model. The electron beam 10 deflected by the deflection coil 110 is irradiated onto the building surface 118. The electron beam 10 is a heat source for melting the metal powder material and subsequently solidifying it.

[0021] The build chamber 119 further comprises a powder tank 111 for storing metal powder material before it is fed to the base plate 114, and a powder feeder for adjusting the amount of metal powder material fed from the powder tank 111 to the base plate 114. A build is produced on the base plate 114. The base plate 114 supports the build. The powder feeder is not shown in FIG.

[0022] The molding chamber 119 further includes a lifting device 115 for adjusting the vertical position of the base plate 114 as the molding progresses, a heat shield 117 for suppressing the transfer of radiant heat from the molding surface 118 to the entire molding chamber 119, and a powder recovery box 113 for recovering excess metal powder material produced by the operation of the squeegee 112.

[0023] The electron gun chamber 121 may further include a deflection lens for scanning the electron beam 10 on the building surface 118 , and a focusing lens for focusing the electron beam 10 on the building surface 118 .

[0024] The three-dimensional modeling apparatus 1 further includes a control device 116 that controls the photocathode 18, the anode 19, the deflection coil 110, and the lifting device 115, and a high-voltage power supply for forming the electron beam 10. The high-voltage power supply is not shown in FIG.

[0025] The surface of the photocathode 18 may be coated with a pure metal cathode material, such as tungsten (W), a gallium-arsenide (Ga-As), indium-gallium-arsenide (In-Ga-As), indium-phosphide / indium-gallium-arsenide-phosphide (In-P / In-Ga-As-P), or a combination of other materials, such as cesium-silver-oxide (Ag-O-Cs), cesium-iodine (Cs-P), cesium-tellurium (Cs-Te), antimony-cesium (Sb-Cs), gallium-arsenide (Ga-As), indium-gallium-arsenide (In-P / In-Ga-As-P). <cs>), Indium-Phosphide / Indium-Gallium-Arsenide <Cesium> (In-P / In-Ga-As <cs>), lanthanum hexaboride (LaB6), or cesium hexaboride (CeB6), or a bialkali cathode material containing two types of alkali metals, such as antimony-rubidium-cesium (Sb-Rb-Cs), antimony-potassium-cesium (Sb-K-Cs), or antimony-sodium-potassium (Sb-Na-K), or a multialkali cathode material containing three or more types of alkali metals, such as cesium-potassium-antimony (Cs-K-Sb) or cesium-potassium-sodium-antimony (Cs-K-Na-Sb).

[0026] When the modeling process is started, the inside of the modeling chamber 119 and the inside of the electron gun chamber 121 are vacuum pumped to 0.1×10 -4 Pa to 0.1 x 10 -5 The pressure is reduced to any pressure up to 100 Pa. When the pressure inside the electron gun chamber 121 is completely reduced, the electron beam 10 is irradiated from the electron gun chamber 121 to the base plate 114, and the base plate 114 is heated by receiving the energy of the heating electron beam 10. After the base plate 114 is heated to a predetermined temperature, the components inside the modeling chamber 119 other than the base plate 114 are heated by the transfer of radiant heat from the base plate 114.

[0027] The three-dimensional modeling apparatus 1 waits for the heat dissipation to the components inside the modeling chamber 119 other than the base plate 114 to stabilize while maintaining the current value of the electron beam 10 so that the base plate 114 is at a constant temperature. After the heat dissipation and the current value of the electron beam 10 are stabilized, the powder supplying device starts operating. The powder supplying device supplies metal powder material onto the base plate 114, deposits the metal powder material uniformly on the base plate 114, and the first layer of powder bed is heated by preheating the base plate 114.

[0028] In the electron gun chamber 121, electrons are extracted from the surface of the photocathode 18 by laser light 20 that is irradiated onto the surface of the photocathode 18 via the laser optical system and the DLP chip 13. The surface of the photocathode 18 that corresponds to the wavelength of the laser light 20 is made of a pure metal cathode material such as tungsten (W), silver cesium oxide (Ag-O-Cs), cesium-iodine (Cs-P), cesium-tellurium (Cs-Te), antimony-cesium (Sb-Cs), gallium-arsenide (Ga-As), indium-gallium-arsenide (In-Ga-As), indium-phosphide / indium-gallium-arsenide-phosphide <cesium> (In-P / In-Ga-As-P <cs>), Indium-Phosphide / Indium-Gallium-Arsenide <Cesium> (In-P / In-Ga-As <cs>), lanthanum hexaboride (LaB6), or cesium hexaboride (CeB6), or a compound or multilayer film cathode material, such as antimony-rubidium-cesium (Sb-Rb-Cs), antimony-potassium-cesium (Sb-K-Cs), or antimony-sodium-potassium (Sb-Na-K), or a multialkali cathode material containing two types of alkali metals, such as cesium-potassium-antimony (Cs-K-Sb), or cesium-potassium-sodium-antimony (Cs-K-Na-Sb). In the first embodiment, it is assumed that the electron gun chamber 121 outputs a relatively high-power electron beam 10 in order to form a metal object by melting and solidifying a metal powder material. When a relatively low-power electron beam 10 is used to manufacture a molded object, the surface of the photocathode 18 may be formed of a material other than the above-mentioned materials.

[0029] The three-dimensional modeling apparatus 1 irradiates the powder bed of the first layer with a preheating beam and a modeling beam. FIG. 2 is a schematic diagram showing the base plate 114 irradiated with the electron beam 10, as viewed from the side of the electron gun chamber 121. The preheating beam 26 is a defocused electron beam for heating the powder layer. The modeling beam 22 is a focused electron beam for melting the powder bed and then solidifying it to form a model 27. The preheating beam 26 is irradiated before and after the modeling beam 22 is irradiated. The modeling area 24 is also shown in FIG. 2. The arrows in FIG. 2 indicate the progress of the preheating beam 26 or the modeling beam 22.

[0030] FIG. 3 is a diagram for explaining a conventional beam irradiation pattern. FIG. 3 shows the order in which the pre-preheating beam 21, the shaping beam 22, and the post-preheating beam 23 are irradiated during the shaping cycle, and the approximate magnitude relationship of the output of each beam. The irradiation time of each of the pre-preheating beam 21, the shaping beam 22, and the post-preheating beam 23 is, for example, several tens of seconds. The diameter of the beam spot of the shaping beam 22 on the shaping surface 118 is anywhere from 0.1 mm to 2 mm. The anode 19 of the electron gun chamber 121 can adjust the focus position of the beam spot by a width of several tens of mm, and the diameter of the beam spot varies depending on the position. The preheating beam 26 in FIG. 2 is expressed as a combination of the pre-preheating beam 21 and the post-preheating beam 23.

[0031] The shaping beam 22 is irradiated at an arbitrary position in the shaping area 24 at a scanning speed of several thousand m / s by the deflection coil 110. The pre-preheating beam 21 and the post-preheating beam 23 have a defocused and wide beam diameter compared to the shaping beam 22, and are scanned at a higher speed compared to the shaping beam 22. The pre-preheating beam 21 and the post-preheating beam 23 are scanned to lightly sinter the metal powder materials supplied to the shaping area 24, and are therefore repeatedly irradiated to the shaping area 24 for a period ranging from several seconds to several tens of seconds.

[0032] Fig. 4 is a diagram showing the change in output over time of the beam irradiation pattern of the first embodiment. Conventionally, as shown in Fig. 3, each beam is irradiated collectively for a relatively long period, but in the first embodiment, as shown in Fig. 4, the shaping beam 22 and the preheating beam 26 are irradiated alternately and repeatedly for a relatively short period ranging from several tens of milliseconds to several hundreds of milliseconds. As described above, the preheating beam 26 is expressed by combining the front preheating beam 21 and the rear preheating beam 23 into one.

[0033] When the three-dimensional modeling apparatus 1 irradiates the preheating beam 26 onto the modeling area 24, it repeatedly irradiates the preheating beam 26 with a beam spot having a diameter ranging from several hundred μm to several mm, and forms a linear irradiation pattern by connecting multiple beam spots. That is, the three-dimensional modeling apparatus 1 performs reciprocal scanning of the preheating beam 26 so as to fill the entire modeling area 24. However, if the laser beam irradiation surface of the photocathode 18 is made large, for example, on the order of several tens of centimeters, and the total irradiation diameter of the laser beam is also made several tens of centimeters, it may be possible to cover the entire modeling area with the preheating beam diameter.

[0034] After filling the printing area 24 with the preheating beam 26 one or more times, the three-dimensional printing apparatus 1 switches the beam for irradiating the printing area 24 from the preheating beam 26 to the printing beam 22, and irradiates the printing area 24 with the printing beam 22. The area in which the metal powder material can be melted by one printing of the printing beam 22 is an area having a diameter obtained by adding 20% ​​to 50% of the diameter of the original beam spot of the printing beam 22 to the diameter of the original beam spot. When the metal powder material is a material having relatively high thermal conductivity, such as copper or aluminum, the area in which the metal powder material can be melted by one printing of the printing beam 22 is an area having a diameter about twice the diameter of the original beam spot of the printing beam 22. In order to fill the entire surface of the model 27 with the printing beam 22, the three-dimensional printing apparatus 1 scans and moves the printing beam 22 by the deflection coil 110 while overlapping two consecutive beam spots.

[0035] Fig. 5 is a side view showing an outline of the DLP chip 13 and the photocathode 18 in the first embodiment when the photocathode 18 is irradiated with the preheating laser light 20A for generating the preheating beam 26. Fig. 6 is a front view showing an outline of the DLP chip 13 and the photocathode 18 in the first embodiment when the photocathode 18 is irradiated with the preheating laser light 20A for generating the preheating beam 26. Figs. 5 and 6 are diagrams for explaining electrons e extracted from the photocathode 18 when the photocathode 18 is irradiated with the preheating laser light 20A.

[0036] 5 and 6, the DLP chip 13 has a plurality of mirror arrays 131 on its surface, and when the preheating laser light 20A is irradiated onto the surface of the photocathode 18, the plurality of mirror arrays 131 are alternately operated. That is, when the preheating laser light 20A is irradiated onto the photocathode 18, the DLP chip 13 sends the preheating laser light 20A, which is the excitation laser light 20, onto the entire surface of the photocathode 18 with 50% of the total area in operation. This means that when the laser light 20 with energy Q per unit area is emitted from the laser oscillator 11, the energy per unit area of ​​the preheating laser light 20A irradiated onto the surface of the photocathode 18 is 1 / 2 of Q.

[0037] The surface of the photocathode 18 is excited by the preheating laser light 20A, and electrons e are extracted from the surface of the photocathode 18 into a vacuum. The number of electrons e extracted from the surface of the photocathode 18 depends on the energy of the preheating laser light 20A, which is the excitation laser light 20, and the work function of the material of the photocathode 18. By increasing or decreasing the energy of the excitation laser light 20, the number of electrons e extracted from the photocathode 18 can be controlled, and the output of the electron beam 10 that is finally formed can be controlled. When the output of the electron beam 10 is set to 1 / 3 of the energy of the laser light 20 emitted from the laser oscillator 11, the operating state of the multiple mirror arrays 131 of the DLP chip 13 is controlled to 1 / 3 of the area of ​​all the mirror arrays 131.

[0038] Fig. 7 is a side view showing an outline of the DLP chip 13 and the photocathode 18 in the first embodiment when the photocathode 18 is irradiated with the laser beam 20B for shaping to generate the shaping beam 22. Fig. 8 is a front view showing an outline of the DLP chip 13 and the photocathode 18 in the first embodiment when the photocathode 18 is irradiated with the laser beam 20B for shaping to generate the shaping beam 22. Fig. 7 is a diagram for explaining the operating states of the multiple mirror arrays 131 and the electrons e extracted from the photocathode 18 when the photocathode 18 is irradiated with the laser beam 20B for shaping to generate the shaping beam 22 and electrons e are extracted from the photocathode 18. Figure 8 is a diagram for explaining the operating state of multiple mirror arrays 131 when a modeling laser light 20B for generating a modeling beam 22 is irradiated onto a photocathode 18 and electrons e are extracted from the photocathode 18, and the shape of the excitation laser light 20 irradiated onto the surface of the photocathode 18.

[0039] When the photocathode 18 is irradiated with the laser light 20B for modeling, the central part of the plurality of mirror arrays 131 on the surface of the DLP chip 13 is operated, and the peripheral part of the plurality of mirror arrays 131 is in a non-operating state. Therefore, the area on the surface of the photocathode 18 where the light is irradiated is the central part of the surface. However, since the laser light 20B for modeling, which is the laser light 20 for excitation, is irradiated in a concentrated manner on the central part of the surface of the photocathode 18, the number of electrons e extracted from the photocathode 18 per unit time is large, and the number of electrons e extracted per unit area is also large compared to when the laser light 20A for preheating is irradiated to the photocathode 18. That is, the three-dimensional modeling device 1 can form the electron beam 10 with a high energy density and a small beam spot diameter.

[0040] In the three-dimensional printing apparatus 1 of embodiment 1, when preheating laser light 20A is irradiated to the photocathode 18, the energy of the light incident on the photocathode 18 is reduced to half of the energy of the light incident on the DLP chip 13, thereby reducing the number of electrons e extracted from the surface of the photocathode 18.

[0041] 9 is a diagram for explaining the preheating laser light 20A and the modeling laser light 20B irradiated to the photocathode 18 in the first embodiment. The DLP chip 13 adjusts the light shape and light amount of the laser light having a wavelength of, for example, 525 nm. The laser light 20 whose light shape and light amount have been adjusted by the DLP chip 13 is irradiated to the photocathode 18. Specifically, the preheating laser light 20A or the modeling laser light 20B is irradiated to the photocathode 18.

[0042] When the photocathode 18 is irradiated with the laser light 20B for modeling, the laser light 20B for modeling is focused and irradiated to the center of the surface of the photocathode 18. When the photocathode 18 is irradiated with the laser light 20A for preheating, the laser light 20A for preheating is defocused and irradiated to the entire surface of the photocathode 18. The laser light 20A for preheating and the laser light 20B for modeling are switched between frequencies ranging from 1 kHz to 10 kHz and irradiated to the photocathode 18.

[0043] Fig. 10 is a diagram showing how the preheating beam 26 and the shaping beam 22 are switched and irradiated onto the shaping area 24. As shown in Fig. 10, the preheating beam 26 and the shaping beam 22 are switched and irradiated onto the shaping area 24 at a frequency ranging from 1 kHz to 10 kHz.

[0044] As described above, the three-dimensional modeling apparatus 1 according to the first embodiment has an electron gun. The electron gun has a photocathode 18, a laser optical system constituted by a laser oscillator 11 and a collimation lens 12, and a DLP chip 13 located between the laser optical system and the photocathode 18 and having a function of adjusting the light shape and light amount of the laser light 20 incident on the surface of the photocathode 18. The DLP chip 13 can modulate the diameter and output of the electron beam 10 at a relatively high speed. Since the electron gun according to the first embodiment has the DLP chip 13, it is possible to shorten the time required to manufacture a three-dimensional object from a metal powder material.

[0045] Embodiment 2 11 is a diagram showing an outline of the configuration of a three-dimensional modeling apparatus 1A according to the second embodiment. The three-dimensional modeling apparatus 1A includes a photocathode 18, a first laser oscillator 31 that generates and outputs a preheating laser beam 20A, a first collimation lens 32 that collimates the preheating laser beam 20A output from the first laser oscillator 31, a first focus lens 33, a first reflecting mirror 34, and a second reflecting mirror 35. The preheating laser beam 20A is a first laser beam for exciting the surface of the photocathode 18. The first laser oscillator 31, the first collimation lens 32, the first focus lens 33, the first reflecting mirror 34, and the second reflecting mirror 35 constitute a first laser optical system that irradiates the first laser beam for exciting the surface of the photocathode 18.

[0046] The first focus lens 33 focuses the preheating laser light 20A collimated by the first collimation lens 32 onto the first reflecting mirror 34. The first reflecting mirror 34 reflects the preheating laser light 20A from the first focus lens 33 to travel to the second reflecting mirror 35. The second reflecting mirror 35 reflects the preheating laser light 20A from the first reflecting mirror 34 to travel to the photocathode 18.

[0047] The three-dimensional modeling apparatus 1A further includes a second laser oscillator 41 that generates and outputs a laser beam 20B for modeling, a second collimation lens 42 that collimates the laser beam 20B for modeling output from the second laser oscillator 41, a second focus lens 43, a third reflecting mirror 44, and a fourth reflecting mirror 45. The laser beam 20B for modeling is a second laser beam for exciting the surface of the photocathode 18. The second laser oscillator 41, the second collimation lens 42, the second focus lens 43, the third reflecting mirror 44, and the fourth reflecting mirror 45 configure a second laser optical system that irradiates the second laser beam for exciting the surface of the photocathode 18.

[0048] The first laser optical system forms a first laser light for forming a defocused electron beam that is irradiated from the photocathode 18 to the metal powder material. The second laser optical system forms a second laser light for forming a focused electron beam that is irradiated from the photocathode 18 to the metal powder material. The second laser light is more focused on the surface of the photocathode 18 than the first laser light.

[0049] The three-dimensional printing apparatus 1A further includes the anode 19, the deflection coil 110, and the printing chamber 119 included in the three-dimensional printing apparatus 1 according to the embodiment 1. The three-dimensional printing apparatus 1A further includes a control device 116A that controls the first laser optical system, the second laser optical system, the photocathode 18, the anode 19, the deflection coil 110, and the printing chamber 119.

[0050] The three-dimensional modeling apparatus 1 according to the first embodiment has one laser optical system, and uses the DLP chip 13 to control the laser light incident on the surface of the photocathode 18, thereby controlling the number of electrons extracted from the photocathode 18. The three-dimensional modeling apparatus 1A according to the second embodiment has two laser optical systems, a first laser optical system and a second laser optical system, and does not have the DLP chip 13. The three-dimensional modeling apparatus 1A controls the number of electrons extracted from the photocathode 18 by switching between a state in which the first laser oscillator 31 included in the first laser optical system outputs a laser light and the second laser oscillator 41 included in the second laser optical system does not output a laser light, and a state in which the second laser oscillator 41 outputs a laser light and the first laser oscillator 31 does not output a laser light.

[0051] The laser light output from the first laser oscillator 31 passes through the first collimation lens 32 and the first focus lens 33, and is irradiated onto the surface of the photocathode 18 via the first reflecting mirror 34 and the second reflecting mirror 35. The laser light output from the second laser oscillator 41 passes through the second collimation lens 42 and the second focus lens 43, and is irradiated onto the surface of the photocathode 18 via the third reflecting mirror 44 and the fourth reflecting mirror 45. The laser light output from the second laser oscillator 41 is irradiated only onto the center of the surface of the photocathode 18.

[0052] Compared to the three-dimensional modeling apparatus 1 according to the first embodiment having the DLP chip 13, the three-dimensional modeling apparatus 1A according to the second embodiment controls the number of electrons extracted from the photocathode 18 only by the light shape focused by each lens, and controls the light shape and light amount of the electron beam irradiated to the metal powder material. The three-dimensional modeling apparatus 1A has a relatively simple structure without the DLP chip 13 and can perform switching of beam irradiation similar to that of the first embodiment. In addition, the three-dimensional modeling apparatus 1A can combine the laser light irradiated from the first laser optical system and the laser light irradiated from the second laser optical system, and can irradiate laser light of a shape that is difficult to realize with the three-dimensional modeling apparatus 1.

[0053] Embodiment 3 12 is a diagram showing an outline of the configuration of a three-dimensional printing apparatus 1B according to embodiment 3. As with the three-dimensional printing apparatus 1 according to embodiment 1, the three-dimensional printing apparatus 1B includes a laser oscillator 11, a collimation lens 12, a DLP chip 13, a focus lens 14, a collector 15, a photocathode 18, an anode 19, a deflection coil 110, a printing chamber 119, and a control device 116. In embodiment 3, the collimation lens 12 is located between the DLP chip 13 and the focus lens 14. In embodiment 3, the laser oscillator 11 constitutes a laser optical system.

[0054] In the third embodiment, the base material of the photocathode 18 is made of a material that transmits laser light having a wavelength of 200 nm to 1100 nm. The base material of the photocathode 18 is made of, for example, magnesium fluoride (MgF 2 ), sapphire, quartz glass, UV-transmitting glass, or borosilicate glass. 2 ), sapphire, quartz glass, ultraviolet transmitting glass, and borosilicate glass each transmit laser light with a wavelength of 100 nm to 1100 nm. In the third embodiment, the rear surface of the photocathode 18 is irradiated with laser light 20.

[0055] The surface of the photocathode 18 may be made of, for example, cesium-oxide silver (Ag-O-Cs), cesium-iodine (Cs-P), cesium-tellurium (Cs-Te), antimony-cesium (Sb-Cs), gallium-arsenide (Ga-As), indium-gallium-arsenide (In-Ga-As), indium-phosphide / indium-gallium-arsenide-phosphide <cesium> (In-P / In-Ga-As-P <cs>), Indium-Phosphide / Indium-Gallium-Arsenide <Cesium> (In-P / In-Ga-As <cs>), lanthanum hexaboride (LaB6), or cesium hexaboride (CeB6), or a multi-layer cathode material, for example, a bialkali cathode material containing two types of alkali metals, for example, antimony-rubidium-cesium (Sb-Rb-Cs), antimony-potassium-cesium (Sb-K-Cs), or antimony-sodium-potassium (Sb-Na-K), or a multi-alkali cathode material containing three or more types of alkali metals, for example, cesium-potassium-antimony (Cs-K-Sb) or cesium-potassium-sodium-antimony (Cs-K-Na-Sb), is deposited in a single layer or multi-layer film to a thickness of about several hundred nm. That is, a thin film formed of any of the above materials is located on the surface of the photocathode 18. The film thickness of the thin film is 300 nm to 500 nm. By irradiating the thin film with laser light, electrons are extracted from the thin film, and an electron beam is formed.

[0056] The photocathode 18 in the first and second embodiments may be replaced with the photocathode 18 in the third embodiment.

[0057] The configuration of the three-dimensional modeling apparatus 1B makes it possible to irradiate the photocathode 18 with the laser light 20 in the direction of electron extraction. The configuration of the three-dimensional modeling apparatus 1B makes it possible to make the laser light 20 incident on the photocathode 18 without using a reflecting plate or a reflecting mirror. The configuration of the three-dimensional modeling apparatus 1B makes it unnecessary to consider that the light shape changes from a circle to an ellipse when the laser light 20 is incident on the surface of the photocathode 18 at an angle, and as a result, the laser optical system can be simplified.

[0058] Embodiment 4 FIG. 13 is a diagram showing an outline of the configuration of a three-dimensional printing apparatus 1C according to the fourth embodiment. The three-dimensional printing apparatus 1C has the laser oscillator 11, the collimation lens 12, the DLP chip 13, the focus lens 14, the collector 15, the photocathode 18, the anode 19, and the printing chamber 119 that the three-dimensional printing apparatus 1 according to the first embodiment has. In the fourth embodiment, the collimation lens 12 is located between the DLP chip 13 and the focus lens 14. In the fourth embodiment, the laser oscillator 11 constitutes a laser optical system. In the fourth embodiment, the laser oscillator 11 outputs a laser light 20 having a wavelength ranging from 200 nm to 1100 nm. The collimation lens 12 and the focus lens 14 are located in front of the surface of the photocathode 18.

[0059] In the fourth embodiment, the laser light 20 that has passed through the focus lens 14 proceeds toward the surface of the photocathode 18 without changing the direction of travel that it took when passing through the focus lens 14. That is, in the fourth embodiment, the laser light 20 is irradiated onto the surface of the photocathode 18 in a direction opposite to the direction in which electrons are extracted from the photocathode 18. More specifically, the laser light 20 is irradiated onto the surface of the photocathode 18 from the front of the surface of the photocathode 18.

[0060] The three-dimensional modeling apparatus 1C further includes a first deflection coil 51 that deflects the electron beam 10 accelerated by the anode 19, and a final deflection coil 52 that further deflects the electron beam 10 deflected by the first deflection coil 51. The first deflection coil 51 tilts or curves the electron beam 10 accelerated by the anode 19 so that the electron beam 10 passes through the final deflection coil 52. The first deflection coil 51 and the final deflection coil 52 are examples of two or more deflection coils for bending the trajectory of electrons. In the fourth embodiment, the electrons extracted from the photocathode 18 are accelerated by the anode 19, and then pass through the first deflection coil 51 and the final deflection coil 52 to be irradiated onto the modeling surface 118. The three-dimensional modeling apparatus 1C further includes a control device 116C that controls the photocathode 18, the anode 19, and the final deflection coil 52.

[0061] In the fourth embodiment, as described above, the laser beam 20 is irradiated onto the surface of the photocathode 18 from the front side of the surface of the photocathode 18. As a result, in the three-dimensional printing apparatus 1C according to the fourth embodiment, it is possible to eliminate a reflector, a reflecting mirror, and an optical lens for suppressing aberration of the light shape caused by the laser beam 20 being incident from an oblique direction with respect to the surface of the photocathode 18.

[0062] Embodiment 5. FIG. 14 is a diagram showing an outline of the configuration of a three-dimensional printing apparatus 1D according to the fifth embodiment. The three-dimensional printing apparatus 1D includes the laser oscillator 11, the collimation lens 12, the DLP chip 13, the focus lens 14, the collector 15, the photocathode 18, the anode 19, the deflection coil 110, the printing chamber 119, and the control device 116 included in the three-dimensional printing apparatus 1 according to the first embodiment. In the fifth embodiment, the laser oscillator 11 constitutes a laser optical system. In the fifth embodiment, the laser oscillator 11 outputs a laser beam 20 having a wavelength ranging from 100 nm to 1100 nm. In the fifth embodiment, the collimation lens 12 is located between the DLP chip 13 and the focus lens 14. The collimation lens 12 and the focus lens 14 collect the light emitted from the DLP chip 13.

[0063] The three-dimensional modeling apparatus 1D further includes an electron gun chamber 121D in which a photocathode 18 is stored. The inside of the electron gun chamber 121D is depressurized in the same manner as the inside of the electron gun chamber 121 in the first embodiment. The three-dimensional modeling apparatus 1D further includes a housing 61 in contact with the emission port of the laser oscillator 11. The emission port is an exit port of the laser beam 20 when the laser beam 20 is emitted from the laser oscillator 11. The collimation lens 12, the DLP chip 13, the focus lens 14, and the collector 15 are stored inside the housing 61. That is, in the fifth embodiment, the collimation lens 12, the DLP chip 13, the focus lens 14, and the collector 15 are not located in the electron gun chamber 121D. The housing 61 is isolated from the electron gun chamber 121D.

[0064] The housing 61 has a protective glass 91 for allowing the laser light that has passed through the focus lens 14 to travel to the photocathode 18. The protective glass 91 is made of a material that transmits laser light with wavelengths from 200 nm to 1100 nm because it is necessary for the protective glass 91 to pass the excitation laser light 20. For example, the protective glass 91 is made of magnesium fluoride (MgF 2 ), sapphire, quartz glass, ultraviolet-transmitting glass, or borosilicate glass.

[0065] The inside of the housing 61 is filled with an inert gas such as nitrogen (N), argon (Ar), or helium (He). The inside of the housing 61 is pre-pressurized to a pressure equal to or higher than atmospheric pressure. That is, the gas pressure inside the housing 61 is higher than the gas pressure inside the electron gun chamber 121D. The DLP chip 13 is covered with an inert gas pre-pressurized to a pressure equal to or higher than atmospheric pressure. This allows the energy of the excitation laser light 20 to be dissipated as heat around the DLP chip 13 to cool the DLP chip 13, so that the three-dimensional printing apparatus 1D can irradiate the photocathode 18 with a higher output of the excitation laser light 20 than any of the three-dimensional printing apparatuses 1, 1A, 1B, and 1C from the first to fourth embodiments.

[0066] That is, the output of the excitation laser light 20 incident on the photocathode 18 in the fifth embodiment is higher than the output of the excitation laser light 20 incident on the photocathode 18 in the other embodiments. Therefore, the three-dimensional printing apparatus 1D according to the fifth embodiment can make the output of the electron beam 10 extracted from the photocathode 18 higher than the output of the electron beam 10 extracted from the photocathode 18 in the other embodiments.

[0067] The fifth embodiment does not require the beam splitter 16, the first reflector 17A, and the second reflector 17B in the first embodiment. Therefore, the three-dimensional printing device 1D according to the fifth embodiment can obtain the same effects as those obtained by the three-dimensional printing device 1 according to the first embodiment with a simple configuration.

[0068] Each of the three-dimensional printing apparatuses 1, 1A, 1B, 1C, and 1D in the first to fifth embodiments may alternately irradiate the metal powder material with a preheating beam for sintering the metal powder material and a shaping beam, which is an electron beam irradiated to the metal powder according to the shape of the object after the metal powder material is sintered, at a time of one second or less. This allows the three-dimensional printing apparatuses 1, 1A, 1B, 1C, and 1D to irradiate the shaping beam while keeping the temperature of the shaping surface 118 constant. The preheating beam is an electron beam for suppressing the repulsive force due to the charging of the metal powder material and suppressing the scattering of the metal powder material when the shaping beam is irradiated to the metal powder material.

[0069] Each of the three-dimensional printing devices 1, 1A, 1B, 1C, and 1D of embodiments 1 to 5 may alternate between a preheating beam for sintering the metal powder material and a printing beam, which is an electron beam that is irradiated to the metal powder material to match the shape of the printed object after the metal powder material has been sintered, in a time period of less than one second, and may alternately irradiate the metal powder material with 10 nanoseconds as the lower limit of the switching speed of the adjustment device, and 1 femtosecond depending on the switching speed of the laser light source.

[0070] Fig. 15 is a diagram showing the processor 81 in the case where the control device 116 of the three-dimensional printing apparatus 1 according to the first embodiment is realized by the processor 81. That is, the function of the control device 116 may be realized by the processor 81 that executes a program stored in a memory 82. The processor 81 is a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, or a DSP (Digital Signal Processor). The memory 82 is also shown in Fig. 15.

[0071] When the function of the control device 116 is realized by the processor 81, the function is realized by the processor 81 and software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 82. The processor 81 realizes the function of the control device 116 by reading and executing the program stored in the memory 82.

[0072] When the functions of the control device 116 are realized by the processor 81, the 3D printing apparatus 1 has a memory 82 for storing a program that results in the steps executed by the control device 116. It can also be said that the program stored in the memory 82 causes the computer to execute the control device 116.

[0073] The memory 82 is, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), an EEPROM (registered trademark) (Electrically Erasable Programmable Read-Only Memory), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disk).

[0074] 16 is a diagram showing the processing circuit 83 in the case where the control device 116 of the three-dimensional printing apparatus 1 according to the first embodiment is realized by the processing circuit 83. That is, the control device 116 may be realized by the processing circuit 83. The processing circuit 83 is dedicated hardware. The processing circuit 83 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. A part of the control device 116 may be dedicated hardware separate from the rest.

[0075] Some of the functions of the control device 116 may be implemented by software or firmware, and the remaining functions may be implemented by dedicated hardware. In this manner, the functions of the control device 116 may be implemented by hardware, software, firmware, or a combination thereof.

[0076] The control device 116A of the three-dimensional printing apparatus 1A according to the second embodiment may be realized by a processor or a processing circuit. The control device 116C of the three-dimensional printing apparatus 1C according to the fourth embodiment may be realized by a processor or a processing circuit. The above processor is a processor similar to the processor 81. The above processing circuit is a processing circuit similar to the processing circuit 83.

[0077] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0078] 1, 1A, 1B, 1C, 1D three-dimensional modeling apparatus, 10 electron beam, 11 laser oscillator, 12 collimation lens, 13 DLP chip, 14 focus lens, 15 collector, 16 beam splitter, 17A first reflector, 17B second reflector, 18 photocathode, 19 anode, 20 laser light, 20A preheating laser light, 20B modeling laser light, 21 pre-preheating beam, 22 modeling beam, 23 post-preheating beam, 24 modeling area, 26 preheating beam, 27 modeled object, 31 first laser oscillator, 32 first collimation lens, 33 first focus lens, 34 first reflecting mirror, 35 second reflecting mirror, 41 second laser oscillator, 42 second collimation lens, 43 second focus lens, 44 Third reflecting mirror, 45 Fourth reflecting mirror, 51 First deflection coil, 52 Final deflection coil, 61 Housing, 81 Processor, 82 Memory, 83 Processing circuit, 91 Protective glass, 110 Deflection coil, 111 Powder tank, 112 Squeegee, 113 Powder collection box, 114 Base plate, 115 Lifting device, 116, 116A, 116C Control device, 117 Heat shield, 118 Build surface, 119 Build chamber, 121, 121D Electron gun room, 131 Mirror array.< / cs> < / cs> < / cs> < / cs> < / cs> < / cs>

Claims

1. A photocathode; a laser optical system that irradiates a laser beam for exciting a surface of the photocathode; an electron gun having an adjustment device located between the laser optical system and the photocathode, the adjustment device adjusting a light shape and a light amount of the laser light incident on a surface of the photocathode; irradiating a metal powder material with an electron beam based on the electrons extracted from the photocathode to manufacture a three-dimensional object; The metal powder material is irradiated with a shaping beam, which is the electron beam that is irradiated to the metal powder material in accordance with the shape of the object, after a period of 1 second or less and 10 nanoseconds or more after irradiation with a preheating beam that sinters the metal powder material, and the preheating beam and the shaping beam are alternately irradiated to the metal powder material such that the preheating beam is irradiated after a period of 1 second or less and 1 femtosecond or more after irradiation of the shaping beam depending on a switching speed of a laser light source. A three-dimensional modeling apparatus comprising:

2. A photocathode; a first laser optical system that irradiates a first laser beam for exciting a surface of the photocathode; a second laser optical system that irradiates a surface of the photocathode with a second laser beam for exciting the surface of the photocathode; the first laser optical system forms the first laser light for forming a defocused electron beam to be irradiated from the photocathode to an irradiation target; the second laser optical system forms the second laser light for forming a focused electron beam which is irradiated from the photocathode to an irradiation target; an electron gun in which the second laser beam is focused on a surface of the photocathode more than the first laser beam; irradiating a metal powder material with an electron beam based on the electrons extracted from the photocathode to manufacture a three-dimensional object; The metal powder material is irradiated with a shaping beam, which is the electron beam that is irradiated to the metal powder material in accordance with the shape of the object, after a period of 1 second or less and 10 nanoseconds or more after irradiation with a preheating beam that sinters the metal powder material, and the preheating beam and the shaping beam are alternately irradiated to the metal powder material such that the preheating beam is irradiated after a period of 1 second or less and 1 femtosecond or more after irradiation of the shaping beam depending on a switching speed of a laser light source. A three-dimensional modeling apparatus comprising:

3. An electron gun having a photocathode, a laser optical system which irradiates laser light for exciting a surface of the photocathode, and an adjustment device located between the laser optical system and the photocathode and which adjusts the light shape and light amount of the laser light incident on the surface of the photocathode; An anode that accelerates the electrons; two or more deflection coils for bending the trajectory of the electrons; The laser optical system includes: a laser oscillator that outputs the laser light having a wavelength in the range of 200 nm to 1100 nm; a collimation lens and a focus lens located in front of the surface of the photocathode; The electrons extracted from the photocathode are accelerated by the anode, and then pass through the two or more deflection coils to be irradiated onto a printing surface; irradiating a metal powder material with an electron beam based on the electrons extracted from the photocathode to manufacture a three-dimensional object; The metal powder material is irradiated with a shaping beam, which is the electron beam that is irradiated to the metal powder material in accordance with the shape of the object, after a period of 1 second or less and 10 nanoseconds or more after irradiation with a preheating beam that sinters the metal powder material, and the preheating beam and the shaping beam are alternately irradiated to the metal powder material such that the preheating beam is irradiated after a period of 1 second or less and 1 femtosecond or more after irradiation of the shaping beam depending on a switching speed of a laser light source. A three-dimensional modeling apparatus comprising:

4. An electron gun having a photocathode, a laser optical system which irradiates laser light for exciting a surface of the photocathode, and an adjustment device located between the laser optical system and the photocathode and which adjusts the light shape and light amount of the laser light incident on the surface of the photocathode; A collimation lens; A focus lens; a housing in which the collimation lens and the focus lens are stored; an electron gun chamber in which the photocathode is housed; The housing also houses the adjustment device, the laser optical system has a laser oscillator that outputs the laser light having a wavelength in the range of 200 nm to 1100 nm; The collimation lens and the focus lens collect the light emitted from the adjustment device, The housing is isolated from the electron gun chamber, the pressure of the gas inside the housing is higher than the pressure of the gas inside the electron gun chamber, irradiating a metal powder material with an electron beam based on the electrons extracted from the photocathode to manufacture a three-dimensional object; The metal powder material is irradiated with a shaping beam, which is the electron beam that is irradiated to the metal powder material in accordance with the shape of the object, after a period of 1 second or less and 10 nanoseconds or more after irradiation with a preheating beam that sinters the metal powder material, and the preheating beam and the shaping beam are alternately irradiated to the metal powder material such that the preheating beam is irradiated after a period of 1 second or less and 1 femtosecond or more after irradiation of the shaping beam depending on a switching speed of a laser light source. A three-dimensional modeling apparatus comprising:

5. a substrate of the photocathode is formed using magnesium fluoride, sapphire, quartz glass, ultraviolet-transmitting glass, or borosilicate glass that transmits laser light having a wavelength of 200 nm to 1100 nm; a thin film of a metal or metal compound is located on a surface of the photocathode; When the thin film is irradiated with a laser beam, electrons are extracted from the thin film to form an electron beam. The three-dimensional modeling apparatus according to claim 1 .

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