JP7301634B2 - Three-dimensional modeling apparatus and method for manufacturing three-dimensional model - Google Patents

Description

TECHNICAL FIELD The present invention relates to a three-dimensional modeling apparatus according to a so-called powder layered melting method, and a method of manufacturing a three-dimensional model using the three-dimensional modeling apparatus.

In recent years, so-called 3D printers have been actively developed, and various methods have been tried. For example, various methods are known, such as a hot fusion layered manufacturing method, a stereolithography method using a photocurable resin, and a powder layered melting method.
In the powder bed fusion method, a process of laying raw material powders such as nylon resin, ceramics, metals, etc. in layers and a process of selectively melting a part of the powder layer by irradiating a laser beam are repeated. This is a method of forming a three-dimensional structure by Instead of laser light, other heating means such as electron beams may be used to selectively melt portions of the powder layer.

In recent years, as a method for manufacturing articles that require high mechanical strength and good thermal conductivity, the powder layered melting method using metal powder as a raw material has begun to be utilized.
In the powder spreading process of spreading metal powder in a layer, a powder spreading member (recoater) such as a squeegee or roller is used to form a layer of powder on the modeling stage. As an example, in the forward direction of the recoater's reciprocating motion, an appropriate amount of powder is conveyed onto the modeling stage with a squeegee or the like, and in the returning direction, a roller adjusted to an appropriate spacing from the modeling stage is used to even out the powder to a thickness of one layer. is mentioned. Although the method of forming the powder layer is not limited to this example, the beam irradiation process is performed after the powder spreading process. In the beam irradiation process, the powder layer is sintered or melted by scanning and irradiating the aforementioned laser beam or electron beam onto the powder layer according to the shape of the object to be created. After beam irradiation, the modeling stage is lowered by one layer and the powder spreading process is performed again. By repeating the above operations, a three-dimensional object is formed.

In modeling using metal powder as a raw material, when the beam is irradiated and heated, the powder layer locally becomes very hot and metal vapor is generated, and the metal vapor condenses in the space above the powder layer. Micrometer-level particles are generated. Such microparticles are called fumes, and the fumes drift along the laser beam path and adhere to the irradiation window through which the laser beam from the light source enters. If fume stays in the optical path or adheres to the irradiation window, it absorbs or reflects the laser beam, affecting the intensity of the laser beam that irradiates the powder layer, changing the state of melting and sintering of the powder layer, and making molding impossible. become stable.

Patent Literature 1 describes a method of removing fumes by arranging a gas supply nozzle and an exhaust nozzle facing each other on a modeling area to perform air curtain-like exhaust.
Further, Japanese Patent Laid-Open No. 2002-200002 describes a method of ensuring stability of laser irradiation intensity by heating an irradiation window through which a laser is incident to prevent adhesion of fumes.

By the way, in recent years, silicon carbide, which is a material that is difficult to machine, is expected to be used in a wide range of fields due to its light weight, wear resistance, thermal shock resistance, and chemical stability. is being considered. However, silicon carbide is a material that does not have a melting point under normal pressure and sublimes at around 2545° C. (or 2700° C., according to various theories).

Patent Document 3 discloses a method of forming a powder layer by forming a powder layer with a mixed powder containing silicon carbide powder and metal boride powder having a melting point lower than the sublimation temperature of silicon carbide, and irradiating an energy beam to form a shape. It is This method utilizes the fact that a mixture of silicon carbide and metal boride becomes eutectic or hypoeutectic when heated, and causes a transitional liquid phase in silicon carbide when heated to melt and solidify a powder layer.

WO2011/049143 Japanese Patent Publication No. 2008-510633 JP 2019-64226 A

Using the mixed powder containing the silicon carbide powder described above and the metal boride powder having a melting point lower than the sublimation temperature of silicon carbide, the powder layer formation and energy beam irradiation are repeated to stack the solidified layers. In some cases, unintended projections were formed in the solidified layer. Unintended protrusions are hard, and when protrusions are formed, not only does the shape accuracy of the three-dimensional model decrease, but also the protrusions interfere with the powder-spreading mechanism, causing the three-dimensional model to topple over on the modeling stage. Problems have arisen that the dusting mechanism has stalled or been damaged.
The problem caused by such protrusions could not be solved by the fume countermeasure techniques described in Patent Document 1 and Patent Document 2.

Therefore, when forming a powder layer using a mixed powder containing a silicon carbide powder and a metal boride powder having a melting point lower than the sublimation temperature of silicon carbide and repeatedly irradiating an energy beam to laminate a solidified layer, , there has been a demand for a technique for suppressing the formation of unintended projections. Moreover, even when other powders are used as raw materials, there has been a demand for a technique for suppressing the formation of unintended protrusions.

According to one aspect of the present invention, a powder layer forming unit that forms a powder layer, an energy beam source that irradiates the powder layer formed by the powder layer forming unit with an energy beam, and the energy beam source that irradiates the powder layer with the energy beam. and a shielding part that shields the powder scattered from the powder layer when irradiating the powder layer so that it does not reach the powder layer forming part. The three-dimensional modeling apparatus is characterized in that it takes an extended posture when irradiating the powder layer with the energy beam, and takes a bent posture when the powder layer forming section forms the powder layer.

Further, another aspect of the present invention is a method for manufacturing a three-dimensional structure in which a powder layer forming process by a powder layer forming unit and an energy beam irradiation process to the powder layer are repeatedly performed, In the energy beam irradiation process, the powder scattered from the powder layer is shielded by the shielding part so that it does not reach the powder layer forming part , and in the energy beam irradiation process, the powder that reaches the shielding part is dropped. A method for manufacturing a three-dimensional model characterized by:

According to the present invention, for example, a mixed powder containing silicon carbide powder and a metal boride powder having a lower melting point than the sublimation temperature of silicon carbide is used to form a powder layer, which is repeatedly irradiated with an energy beam and solidified. When laminating layers, it is possible to suppress the formation of unintended protrusions.

FIG. 4 is a schematic diagram showing a state during laser irradiation in the three-dimensional modeling apparatus of Embodiment 1; (a) A schematic diagram showing a state after laser irradiation in Embodiment 1. FIG. (b) A schematic diagram showing one stage of the powder layer formation process in Embodiment 1. FIG. (c) A schematic diagram showing a state in which the shielding member is bent and the recoater is moved in the first embodiment. (a) to (c) are schematic diagrams showing each stage of the powder layer forming process in Embodiment 1. FIG. FIG. 4 is a schematic diagram showing a stage where powder layer formation is completed in Embodiment 1; (a) A schematic diagram showing a state during laser irradiation in the second embodiment. (b) A schematic diagram showing a preliminary stage of the powder layer forming process in Embodiment 2. FIG. (a) A schematic diagram showing a state during laser irradiation in Embodiment 3. FIG. (b) A schematic diagram showing a preliminary stage of the powder layer forming process in Embodiment 3. FIG. 4 is a schematic diagram showing a state during laser irradiation in Embodiment 4. FIG. FIG. 12 is a schematic diagram showing a state during laser irradiation in Embodiment 5; (a) A schematic diagram showing a state during laser irradiation in Embodiment 6. FIG. (b) A schematic diagram showing one stage of the powder layer forming process in Embodiment 6. FIG. (a) The perspective view of the metal curtain which is a modification of Embodiment 6. FIG. (b) Side view of the metal curtain in a stretched state. (c) Side view of the metal curtain in a curved state. (a) A schematic diagram for explaining a state in which a powder layer is irradiated with a laser beam in a conventional three-dimensional modeling apparatus. (b) A schematic diagram for explaining a situation in which an adhering matter falls when forming a powder layer in a conventional three-dimensional modeling apparatus. (a) A schematic diagram for explaining a state in which a laser is irradiated in a state in which an adhering matter has fallen on a powder layer in a conventional three-dimensional modeling apparatus. (b) A schematic diagram for explaining a state in which projections are formed in a conventional three-dimensional modeling apparatus. A plane photograph of a powder layer after laser irradiation. FIG. 4 is a schematic diagram for explaining a situation in which powder is scattered due to sublimation;

A three-dimensional modeling apparatus and a three-dimensional modeling article manufacturing method according to an embodiment of the present invention will be described with reference to the drawings. In the drawings referred to in the following description, members having the same function are denoted by the same reference numerals unless otherwise specified.

[Embodiment 1]
FIG. 1 is a schematic diagram showing a state in which a powder layer 18 is irradiated with a laser beam 12 in a three-dimensional modeling apparatus 200 of Embodiment 1. FIG.
First, the configuration of the three-dimensional modeling apparatus 200 will be described. A three-dimensional modeling apparatus 200 capable of modeling by the powder layered melting method includes a chamber 1 into which gas can be introduced. The chamber 1 is provided with a gas inlet 4 for introducing nitrogen gas, for example, and a vacuum pump 19 for evacuating the chamber during gas replacement.
Inside the chamber 1 are a modeling plate 11 which is a base for forming a three-dimensional object, a modeling stage 2 on which the modeling plate 11 is detachably mounted, a powder supply tank 3 for storing raw material powder, and a powder supply tank. A powder feed stage 20 supporting 3, a recoater 5 is provided. The modeling stage 2 and the powder supply stage 20 can move up and down independently of each other.

A recoater 5 as a powder layer forming section conveys powder from a powder supply tank 3 as a powder supply section onto the modeling plate 11 to form a powder layer 18 having a predetermined thickness of about 10 to 100 μm. The recoater 5 has a squeegee 6 and rollers 7 . The squeegee 6 has a function of conveying the powder in the powder supply tank 3 to the vicinity of the modeling plate or onto the modeling plate while moving in the R direction. While moving in the R direction or the L direction, the roller 7 conveys the powder onto the modeling plate 11 or onto the modeled object in the process of being shaped, and compresses or extrudes it, thereby flattening the upper surface of the powder layer 18 to form a predetermined powder layer. It has a function to adjust to the thickness of The height of the lower end surface of the squeegee 6 can be changed as appropriate so that the squeegee 6 conveys the powder and the roller 7 flattens the powder layer. That is, the squeegee 6 is configured so that it can take a posture in which the height of the lower end face is the same as the lower end of the roller 7 or a posture in which the height of the lower end face is higher than the lower end of the roller 7 . . The roller 7 moves in the horizontal direction (L direction, R direction) while pressing against the powder. A high-rigidity driving device with suppressed vertical movement is used for .

Recovery grooves 21 are arranged on the left side of the powder supply tank 3 and the right side of the modeling stage 2 in order to recover excess powder when the powder layer is formed by the recoater 5 . The recoater 5 is placed at a position spaced apart from the modeling stage 2 as shown in FIG. 1 when not performing an operation for forming a powder layer, and this position is called a standby position.

In the chamber 1, a shielding member 8 is provided between the standby position of the recoater 5 and the modeling stage 2 as a shielding portion that is a characteristic part of the present embodiment. The shielding member 8 includes upper and lower plate-like members connected via a rotatable joint portion 81 , and can take a bent posture or an extended posture by operating the joint portion 81 . FIG. 1 shows an extended posture, that is, a posture in which the upper and lower plate-like members are linearly arranged along the vertical direction with the joint portion 81 interposed therebetween. The joint portion 81 is arranged at a position higher than the uppermost portion of the recoater 5, and by rotating the joint portion 81, the shielding member 8 does not move even when the recoater 5 is moved in the horizontal direction (L direction-R direction). It is possible to take a bending posture that does not interfere. The bending posture is illustrated in FIGS. 2(c), 3(a) to 3(c), etc., and these figures will be described later.

Outside the chamber 1, there are provided a laser oscillator 15 as an energy beam source, and a scanning optical system 14 having a galvanomirror 16 for scanning the laser beam and an f-θ lens 17 for focusing. . Above the modeling plate 11, there is a transmission window 13 through which the laser beam 12 emitted from the scanning optical system 14 is transmitted. be.

In this embodiment, a fiber laser with a wavelength of 1070 nm (maximum output of 300 W) is used as the laser oscillator 15, for example. A laser beam 12 output from a laser oscillator 15 is directed to a desired position on the surface of a powder layer 18 on a modeling plate 11 by a galvanomirror 16 and an f-θ lens 17 driven according to shape data of a three-dimensional object. is focused and scanned.

Next, a process of forming a three-dimensional modeled object using the three-dimensional modeler 200 will be described.
First, the raw material powder that can be used in this embodiment will be described. In the present embodiment, for example, silicon carbide (SiC) powder (manufactured by Pacific Rundum) having an average particle diameter of Φ14.7 μm and chromium diboride (CrB ₂ ) powder (manufactured by Nippon New Metals) having an average particle diameter of Φ3 to 6 μm are used. A mixture of two powders can be used. Each powder is weighed so that the atomic composition ratio of silicon carbide and chromium diboride is silicon carbide: chromium diboride = 70:30 (at.%), and the weighed powder is placed in a polyethylene bottle and mixed. . The powder supply tank 3 is filled with the mixed powder.

Next, the vacuum pump 19 is used to evacuate the chamber 1 . After sufficiently evacuating the chamber, an inert gas is introduced from the gas inlet 4 so that the pressure in the chamber 1 becomes equal to the atmospheric pressure. Nitrogen (N ₂ ), argon (Ar), or the like can be mainly used as the inert gas, but N ₂ gas is used in this embodiment.

Next, in preparation for the powder layer forming process, the origin of the modeling plate 11 is set in the vertical direction. The modeling stage 2 to which the modeling plate 11 is attached is lowered to an area that does not interfere with the operation area of the rollers 7 of the recoater 5. In this state, the recoater 5 is moved in the L direction-R direction within the operation area including the area directly above the modeling plate 11. to reciprocate. After that, the modeling stage 2 is raised stepwise, and the position (height) at which the modeling plate 11 and the roller 7 come into contact is set as the origin of the modeling plate 11 . In this embodiment, in order to determine contact, a load sensor (not shown) is incorporated in the modeling stage 2, and contact is determined by detecting an increase in load due to contact. The extent to which the load is increased before it is determined to be contact depends on the rigidity of the device, but in the device of this embodiment, it is determined that contact has occurred when a load of 10 N is applied, and that position is the origin of the modeling stage 2 .

In order to form a powder layer on the modeling plate 11, first, the modeling stage 2 is lowered slightly by the thickness of the powder layer to be formed. For example, when the thickness of the powder layer to be formed is set to 50 μm, it is lowered by 70 μm. After that, the powder supply stage 20 supporting the powder supply tank 3 is raised by 120 μm to push the powder upward. Then, the recoater 5 is driven in the R direction with the posture of the squeegee 6 adjusted so that the lower end surface of the squeegee 6 is at the same height as the bottom of the roller 7, and is moved from the standby position to the right side of the powder supply tank 3, The amount of powder necessary for powder spreading is carried to the left side of the modeling stage 2.
Subsequently, the recoater 5 is driven in the R direction to move the recoater 5 to the right side of the modeling stage 2 to spread powder on the modeling stage 2 .

Finally, after the modeling stage 2 is lifted by 20 μm, the recoater 5 is driven in the L direction with the squeegee 6 raised so that the lower end surface of the squeegee 6 is above the bottom of the roller 7 . A powder layer having a uniform thickness of 50 μm is formed on the modeling stage 2 by extruding excess powder out of the modeling area while compressing in the vertical direction using only the rollers 7 . As described above, the powder layer forming process by the recoater 5 as the powder layer forming unit is completed for one layer.

Next, an irradiation process for irradiating the formed powder layer with a laser beam is performed. A modeling model created by CAD or the like is converted into a laser irradiation pattern for each layer using slicer software. The galvanomirror 16 is controlled according to the converted laser irradiation pattern to irradiate the powder layer 18 with the laser beam 12 . For example, the laser power is 100 W, the laser scan speed is 500 mm/s, and the scan pitch is 0.05 mm, but they are not limited to these. When irradiating the laser beam 12, it is desirable to operate a fume collector (not shown) to collect fumes generated when the laser beam 12 is irradiated. The powder in the region irradiated with the laser beam 12 melts and solidifies as a bulk body through the eutectic phenomenon described in Patent Document 3, while the other regions remain in the powder layer state.

After one powder layer has been irradiated with the laser beam 12, the above-described powder spreading process is performed again to lay a powder layer with a mixed powder of silicon carbide and chromium diboride, and a laser beam is applied according to the pattern of the next layer. A beam is directed onto the powder layer. By repeating the above operations, layers containing silicon carbide as a main component are successively stacked to form a three-dimensional three-dimensional object.

In the present embodiment, as shown in FIG. 1, while the powder layer is being irradiated with the laser beam 12, the shielding member 8 is in an extended posture so that the scattering powder 100 does not adhere to the surface of the recoater 5. It implements a characteristic operation to prevent That is, the shielding member 8 is arranged at a position that shields the trajectory of the powder flying toward the recoater from the powder layer irradiated with the laser beam. The position that blocks the trajectory of the powder flying toward the recoater is typically a position that blocks the parabolic trajectory from the powder layer to the recoater. It may be a position that shields the trajectory of Then, as will be described later, when the next powder layer is formed using the recoater 5 , the shielding member 8 is in a bent position so as not to interfere with the operation of the recoater 5 .

In order to facilitate the understanding of this feature, the inventors of the present invention have investigated the cause of the formation of unintended protrusions in the conventional apparatus when the solidified layer is laminated by repeating the formation of the powder layer and the irradiation of the laser beam. Describe your findings.

FIG. 11A is a schematic diagram for explaining a state in which a powder layer is irradiated with a laser beam in a conventional three-dimensional modeling apparatus 300. FIG. Elements common to those of the apparatus of Embodiment 1 shown in FIG. 1 are assigned the same numbers and descriptions thereof are omitted, but it should be noted that the shielding member 8 is not provided in the conventional three-dimensional modeling apparatus 300. do.
In the conventional three-dimensional modeling apparatus 300, the present inventor formed a powder layer 18 made of a mixed powder of silicon carbide and chromium diboride, and then irradiated the laser beam 12. It was found that the particles were scattered and flew up to the recoater 5. As schematically shown in FIG. 11( a ), the powder 100 that flew up to the recoater 5 adhered to the side surface of the recoater 5 or was stacked on the top surface of the recoater 5 . Examination of the powder 100 adhering to the side surface of the recoater 5 and stacked on the upper surface revealed that it had the same composition as the raw material powder used for the powder layer 18 .

FIG. 13 is a micrograph (plan view) taken from above after linearly scanning a powder layer composed of a mixed powder of silicon carbide and chromium diboride with a laser beam. A modeled object (solid) containing silicon carbide and chromium diboride is formed in the laser-irradiated area (the line in the center of the drawing), but there is no powder around the modeled object, and the modeling plate is exposed. I understand. In the photograph, the part that looks whitish along the line is the exposed part of the modeling plate. It is considered that the powder that was in the exposed portion of the modeling plate was scattered, and at least part of it reached the recoater 5 .

With reference to FIG. 14, the mechanism by which the powder around the portion irradiated with the laser beam scatters will be considered. As shown in FIG. 14, when a mixed powder of silicon carbide and chromium diboride is irradiated with a laser, the locally heated portion becomes a liquid state (hereinafter also referred to as a melt pool) due to the eutectic phenomenon. A part of silicon carbide sublimates without going through the eutectic process in the process of changing from the powder state to the liquid state. In other words, silicon carbide powder exists in the vicinity of the surface of the powder layer irradiated with the laser beam, but when the temperature of the silicon carbide powder rises rapidly due to the irradiation of the laser beam, part of it becomes eutectic with chromium diboride. It will sublime above the sublimation temperature before it does. It is presumed that this partial sublimation of silicon carbide blows off the powder 100 around the laser-irradiated portion and eliminates the powder around the line peripheral portion.

This phenomenon becomes more pronounced when the energy applied to the powder from the laser beam is increased, so we tried lowering the laser energy to the extent that modeling is possible. I couldn't. In addition, during laser irradiation, the flow rate (intake/exhaust volume) of the air curtain flowing on the modeling stage was adjusted as a countermeasure against fumes. could not be prevented from adhering to This is because the blown powder 100 has a much higher mass and momentum compared to fume that vapor condenses and floats as sub-micrometer level fine particles.

As schematically shown in FIG. 11(a), if the powder 100 adheres to the side surface of the recoater 5 or is stacked on the top surface of the recoater 5 during laser irradiation, when the recoater 5 forms the next powder layer after laser irradiation, , the powder 100 may fall.

FIG. 11(b) is a schematic diagram for explaining a situation in which the next powder layer is formed using the recoater 5 with the powder 100 attached to the side or loaded on the top. As shown, the recoater 5 is driven in the R direction, and then the recoater 5 is driven in the L direction to form a powder layer. As described above, while the recoater 5 is horizontally moved on the modeling stage 2, the powder 100 adhering to the side surface of the recoater 5 or stacked on the upper surface may fall as a lump. In particular, when the recoater 5 is finally driven in the L direction and moves toward the standby position while being pressed against the powder layer, if the lump of powder 100 falls on the powder layer from the rear end side (right side in the figure), the roller will already be in contact with the powder layer. Since it is after 7 has passed, the lump of powder 100 that has fallen is piled up as it is on the powder layer.

FIG. 12(a) schematically shows a state in which lumps of the powder 100 are piled up on the powder layer 18 and the laser beam 12 for forming the next solidified layer is irradiated. It is a diagram. When a laser beam is irradiated to a portion where lumps of the powder 100 are piled up, an unintended hard protrusion 101 is formed on the three-dimensional structure as shown in FIG. 12(b). Of course, when the protrusion 101 is formed, the shape accuracy of the three-dimensional structure is lowered. Furthermore, when the next powder layer is formed, the protrusions 101 and the recoater 5 interfere with each other, causing problems such as the three-dimensional model overturning on the modeling stage and the recoater 5 stopping or being damaged. was

On the other hand, in the present embodiment, as shown in FIG. 1, the powder 100 that scatters and flies toward the recoater 5 while being irradiated with the laser beam has its trajectory shielded by the shielding member 8 and is placed at the standby position. Since it does not reach the recoater 5 located at the bottom, it does not adhere to the recoater 5 . FIG. 2(a) schematically shows the state of the recoater 5 after the solidified portion 31 forming the three-dimensional structure is formed by irradiating the laser beam. I know not.

After irradiating the laser beam, in this embodiment, the recoater 5 is used to form the next powder layer on the modeling stage in the following procedure.
First, as shown in FIG. 2B, the powder supply stage 20 that supports the powder supply tank 3 is raised to push the powder upward, and the modeling stage 2 is lowered.
Next, as shown in FIG. 2(c), the joint portion 81 is rotated to change the shielding member 8 from the extended posture to the bent posture. That is, the lower end of the shielding member 8 is positioned higher than the upper end of the recoater 5 . As a result, even if the recoater 5 is moved horizontally, it will not interfere with the shielding member 8 . Therefore, the recoater 5 is driven in the R direction so that the lower end surface of the squeegee 6 is at the same height as the bottom of the roller 7, and the amount of powder necessary for powder spreading is carried to the left side of the modeling stage 2. .

Subsequently, as shown in FIG. 3( a ), the recoater 5 is driven in the R direction to move to the right side of the modeling stage 2 to spread powder on the modeling stage 2 .
Further, as shown in FIG. 3(b), the modeling stage 2 is raised, and the recoater 5 whose posture is adjusted so that the lower end surface of the squeegee 6 is positioned higher than the bottom of the roller 7 is driven in the L direction. A powder layer having a uniform thickness is formed while being pressed by a roller 7 .

Then, as shown in FIG. 3(c), the recoater 5 is further driven in the L direction to move toward the standby position. At this time, since the shielding member 8 maintains its bent posture, it does not interfere with the movement of the recoater 5 .
As shown in FIG. 4, after the recoater 5 returns to the standby position, the shielding member 8 is extended before starting the laser beam irradiation in order to shield the recoater 5 from flying powder when the next laser beam is irradiated. return.

In this embodiment, since the shielding member 8 prevents the flying powder 100 from adhering to the recoater 5, the powder 100 adhering to the recoater can be dropped and piled up on the powder layer 18 as in the conventional art. do not have.
Therefore, when a mixed powder containing silicon carbide powder and a metal boride powder having a melting point lower than the sublimation temperature of silicon carbide is used to repeatedly form a powder layer and irradiate an energy beam to form a solidified layer, , it is possible to suppress the formation of unintended projections.

According to the embodiment described above, for example, 400 layers were modeled in a maximum area of 30 mm×40 mm, and a model with maximum dimensions of 30 mm×40 mm×20 mm was obtained. The modeling was completed without stopping, the rollers 7 were not damaged, and the shape accuracy of the three-dimensional model satisfied the predetermined standard. When the apparatus was checked before forming the powder layer during the modeling, there was almost no scattering (powder) originating from the powder for modeling on the surface of the recoater 5 . As described above, it is possible to prevent the scattered matter deposited on the recoater 5 from dropping into the modeling area, and it is possible to obtain a modeling apparatus with high stability in the modeling operation and excellent productivity.

In the embodiment described above, most of the powder 100 that collides with the shielding member 8 adheres to the shielding member 8 as shown in FIG. 2(a). The powder 100 adhering to the shielding member 8 may drop when the orientation is changed from the stretched posture to the bent posture, or when the posture is changed from the bent posture to the stretched posture. However, if the posture of the shielding member 8 is changed at the timing when the recoater 5 is horizontally spaced from the shielding member 8 , even if the powder 100 falls, it will not adhere to the recoater 5 . Moreover, when the recoater 5 passes directly under the shielding member 8, the shielding member 8 is in a bent posture. For example, as shown in FIG. It does not stick to 5. The powder 100 adhering to the shielding member 8 can be sucked and discharged using, for example, a dust cleaner when the chamber is opened after molding.

On the other hand, as a modified example of the present embodiment, a configuration is also possible in which the powder 100 colliding with the shielding member 8 does not adhere to the shielding member 8 . For example, the surface of the shielding member 8 may be coated with a material to which the powder 100 is less likely to adhere, a mechanism for applying ultrasonic vibrations to the shielding member 8 may be provided, or a mechanism for blowing an airflow onto the surface of the shielding member 8 may be provided. It is possible. In that case, while the recoater 5 is in the standby position, the powder 100 that has collided with the shielding member 8 is dropped. 69 may be provided directly below curtain 59 . A dust collector for dust is connected to the collection container 69 so that the removed scattered matter will not scatter again in the apparatus. The recovered powder 100 may be reused as raw material powder for modeling.

[Embodiment 2]
A three-dimensional modeling apparatus 400 according to the second embodiment will be described with reference to FIGS. 5(a) and 5(b). The description of the parts common to the first embodiment is omitted.
In the first embodiment, the shielding member 8 that can be bent and stretched by the joint part 81 is provided as a shielding part, but in this embodiment, the shielding plate 9 that does not bend and stretch but can move up and down like a shutter is provided as a shielding part. . Further, in Embodiment 1, the shielding member 8 as the shielding portion is provided at a position closer to the standby position of the recoater 5 than the powder supply tank 3, but in the present embodiment, the shielding plate 9 as the shielding portion It was arranged above the recovery groove 21 on the left side of the tank 3 .

In this embodiment, as shown in FIG. 5A, the shield plate 9 is lowered while the laser beam 12 is being irradiated, and the shield plate 9 prevents the flying powder 100 from adhering to the recoater 5. To prevent. Of the powder 100 that has collided with the shielding plate 9 , the powder that falls is recovered by the recovery groove 21 .

When the irradiation of the laser beam is finished, the lower end of the shielding plate 9 does not interfere with the upper end of the recoater 5 even when the recoater 5 is moved in the horizontal direction (L direction, R direction) as shown in FIG. 5B. The shielding plate 9 is raised to the height. The shielding plate 9 is housed in a shielding plate housing portion 10 whose inside is kept in the same atmosphere as the chamber-1. A scraper (not shown) that slides on the surface of the shielding plate 9 is provided at the lower end of the shielding plate housing portion 10, and the powder 100 adhering to the surface of the shielding plate 9 is removed when the shielding plate 9 is raised. scrape off The powder 100 scraped off the shielding plate 9 is recovered in the recovery groove 21 .
After the shielding plate 9 is completely lifted, a new powder layer is formed using the recoater 5 as in the first embodiment. When the formation of a new powder layer is completed and the recoater 5 returns to the standby position, the shielding plate 9 is lowered again to the position where the flight trajectory of the powder 100 is interrupted.

According to Embodiment 2, for example, 400 layers were modeled in a maximum area of 30 mm×40 mm, and a modeled object with maximum dimensions of 30 mm×40 mm×20 mm was obtained. The modeling was completed without stopping, the rollers 7 were not damaged, and the shape accuracy of the three-dimensional model satisfied the predetermined standard. When the apparatus was checked before forming the powder layer during the modeling, there was almost no scattering (powder) originating from the powder for modeling on the surface of the recoater 5 . As described above, it is possible to prevent the scattered matter deposited on the recoater 5 from dropping into the modeling area, and it is possible to obtain a modeling apparatus with high stability in the modeling operation and excellent productivity.

In this embodiment, the recovery groove 21 can recover the powder 100 shielded by the shielding plate 9 as well as the powder surplus when forming the powder layer. The recovered powder 100 may be reused as raw material powder for modeling.

[Embodiment 3]
Embodiment 3, which is a modification of Embodiment 2, will be described with reference to FIGS. 6(a) and 6(b). The description of the parts common to the second embodiment is omitted.
In the second embodiment, the vertically movable shielding plate 9 is arranged above the recovery groove 21 on the left side of the powder supply tank 3, but in this embodiment, the vertically movable shielding plate 9 is arranged above the powder supply tank 3. bottom.

In the present embodiment, as shown in FIG. 6A, the shielding plate 9 is lowered while the laser beam 12 is being irradiated to prevent the flying powder 100 from adhering to the recoater 5. prevent by Of the powder 100 that collides with the shielding plate 9 , the falling powder falls into the powder supply tank 3 . Since the powder 100 has the same components as the raw material powder stored in the powder supply tank 3 as described above, there is no problem even if it is mixed with the raw material powder.

When the irradiation of the laser beam is completed, as shown in FIG. 6B, the shielding plate is moved to a height where the lower end of the shielding plate 9 does not interfere even when the recoater 5 is moved in the horizontal direction (L direction, R direction). Raise 9. The shielding plate 9 is housed in a shielding plate housing portion 10 whose inside is kept in the same atmosphere as the chamber-1. A scraper (not shown) that slides on the surface of the shielding plate 9 is provided at the lower end of the shielding plate housing portion 10, and the powder 100 adhering to the surface of the shielding plate 9 is removed when the shielding plate 9 is raised. scrape off The powder 100 scraped off the shielding plate 9 falls into the powder supply tank 3 and is reused as raw material powder.

According to Embodiment 3, for example, 400 layers were modeled in a maximum area of 30 mm×40 mm to obtain a model with maximum dimensions of 30 mm×40 mm×20 mm. The modeling was completed without stopping, the rollers 7 were not damaged, and the shape accuracy of the three-dimensional model satisfied a predetermined standard. When the apparatus was checked before the powder layer was formed during modeling, there was almost no scattering (powder) on the surface of the recoater 5 derived from the powder for modeling. As described above, it is possible to prevent the scattered matter deposited on the recoater 5 from dropping into the modeling area, and it is possible to obtain a modeling apparatus that has high stability in the modeling operation and excellent productivity.
In this embodiment, the powder 100 that has collided with the shielding plate 9 can be mixed with the raw material powder in the powder supply tank 3 and reused without providing a special recovery mechanism.

[Embodiment 4]
A three-dimensional modeling apparatus 500 according to Embodiment 4 will be described with reference to FIG. The description of the parts common to the first embodiment is omitted.
In Embodiments 1 to 3, a movable member is used as the shielding portion, but in this embodiment, a fixed member is used as the shielding portion. That is, in this embodiment, a shielding top plate 49 is provided that extends like an eaves from above the standby position of the recoater 5 toward the modeling plate. The shielding top plate 49 is fixed to the ceiling of the chamber 1 and shields the recoater 5 at the standby position from the flying powder 100 . Although it may be difficult to completely shield the powder 100 flying toward the recoater 5, the amount of scattered matter adhering to the upper portion of the recoater 5 is overwhelmingly large. , the effect of more stable molding can be obtained.

The powder 100 accumulated on the top plate 49 for shielding can be sucked and discharged using, for example, a vacuum cleaner for dust when the chamber is opened after molding.
In this embodiment, since the shielding top plate 49 as the shielding portion has no movable portion, the apparatus structure of the three-dimensional modeling apparatus 500 can be simplified.

According to Embodiment 4, for example, 400 layers were modeled in a maximum area of 30 mm×40 mm to obtain a model with maximum dimensions of 30 mm×40 mm×20 mm. The modeling was completed without stopping, the rollers 7 were not damaged, and the shape accuracy of the three-dimensional model satisfied the predetermined standard. When the apparatus was checked before forming the powder layer in the middle of the modeling, there was almost no scattered matter (powder) originating from the powder for modeling on the surface of the recoater 5 . As described above, it is possible to prevent the scattered matter deposited on the recoater 5 from dropping into the modeling area, and it is possible to obtain a modeling apparatus with high stability in the modeling operation and excellent productivity.

[Embodiment 5]
A three-dimensional modeling apparatus 600 according to Embodiment 5 will be described with reference to FIG. The description of the parts common to the first embodiment is omitted.
In Embodiments 1 to 4, a solid member is used as the shielding portion, but in this embodiment, a fluid is used as the shielding portion. That is, in the present embodiment, the recoater 5 is shielded from the powder 100 by changing the trajectory of the powder 100 flying toward the recoater 5 at the standby position by the flow of air current (air curtain).

As shown in FIG. 8, a sheet nozzle 36 is installed above the powder recovery port 34 between the modeling stage 2 and the standby position of the recoater 5 . Further, the powder recovery port 34 is directly connected to a circulator 32 for capturing and recovering the powder by circulating airflow. Commercially available equipment for fume collectors can be used for the circulator 32, and only the powder out of the gas and powder entering from the powder recovery port 34 can be captured and the air flow can be returned to the sheet nozzle 36. As the circulator 32, for example, a fume collector VF-5H (trade name) manufactured by Amano Corporation can be used.

The sheet nozzle 36 has, for example, an opening of 40 cm in the depth direction of the device and 5 mm in the width direction, and can blow out a sheet-like gas flow with a width of approximately 40 cm. Also, the air volume from the sheet nozzle 36 is adjusted by a bypass nozzle 33 having an ejection hole at a distance from the modeling area and a valve 39 for controlling the air volume flowing through the bypass nozzle 33 . For example, if the circulation rate of the fume collector VF-5H is the specification value of 1.6 cubic meters per minute and the opening from the sheet nozzle 36 is 20 square centimeters, the theoretical maximum is 8000 m per minute, that is, the maximum is 133 m per second. Wind speeds up to Alternatively, the surface of the recoater 5 may be cleaned by blowing an airflow jetted from the bypass nozzle 33 onto the recoater 5 .

After adjusting the powder for modeling, filling the powder supply tank, replacing the internal atmosphere of the chamber 1 with _N2 gas, and setting the origin of the modeling plate in the vertical direction, the circulator 32 is started and the sheet nozzle is The valve 39 is controlled so that the wind speed from 36 is 20 m/s. Thereafter, powder spreading and laser irradiation are repeatedly performed to manufacture a three-dimensional structure.

According to Embodiment 5, for example, 400 layers were modeled in a maximum area of 30 mm×40 mm to obtain a model with maximum dimensions of 30 mm×40 mm×20 mm. The modeling was completed without stopping, the rollers 7 were not damaged, and the shape accuracy of the three-dimensional model satisfied the predetermined standard. When the apparatus was checked before forming the powder layer in the middle of the modeling, there was almost no scattered matter (powder) originating from the powder for modeling on the surface of the recoater 5 . As described above, it is possible to prevent the scattered matter deposited on the recoater 5 from dropping into the modeling area, and it is possible to obtain a modeling apparatus with high stability in the modeling operation and excellent productivity.

In the example of FIG. 8, the gas blown out from the sheet nozzle 36 is circulated by the circulator 32 and reused. . Furthermore, the gas blown out from the sheet nozzle 36 was recovered from the powder recovery port 34 directly below the sheet nozzle 36, but the powder recovery port may be placed on the side of the chamber or in various other ways unless problems such as the powder being blown up by the air flow occur. can be placed in place. Further, it is also possible to provide the vacuum pump 19 with a pressure adjusting mechanism to cause the vacuum pump 19 to discharge.

[Embodiment 6]
A three-dimensional modeling apparatus 700 according to the sixth embodiment will be described with reference to FIGS. 9(a) and 9(b). The description of the parts common to the first embodiment is omitted.
In Embodiments 1 to 3, a movable member is used as the shielding portion, and when the recoater 5 is moved in the horizontal direction, part or all of the shielding portion is moved and retracted so as not to come into contact with the recoater 5 . In contrast, in the present embodiment, the shielding portion comes into contact with the recoater 5 when the recoater 5 is moved in the horizontal direction, but the shielding portion can be easily deformed following the movement of the recoater. Specifically, a flexible curtain 59 was provided as a shield.

As shown in FIG. 9( a ), a curtain 59 is installed as a shield in the space between the standby position of the recoater 5 and the powder supply tank 3 . The curtain 59 has a length such that at least the lowest part thereof is located lower than the upper surface of the recoater 5, and is made of a flexible material such as a resin material such as silicone rubber or fluororubber. . For example, a 1 mm thick sheet material of FB750N manufactured by Kureha Elastomer Co., Ltd., which is a fluorine rubber, is attached to the ceiling of the chamber 1 as a curtain 59 .

As shown in FIG. 9(a), in this embodiment, the powder 100 that has collided with the curtain 59 falls without adhering to the curtain 59. As shown in FIG. For example, it is possible to coat the surface of the curtain 59 with a material that makes it difficult for the powder 100 to adhere, provide a mechanism for applying ultrasonic vibrations to the curtain 59, or provide a mechanism for blowing an air current onto the surface of the curtain 59. . A recovery container 69 for recovering the powder 100 dropped from the curtain 59 is provided below the curtain 59 . A dust collector (not shown) is connected to the collecting container 69 so that the collected powder 100 is prevented from scattering inside the device and adhering to it again. The recovered powder 100 may be reused as raw material powder for modeling.

In this embodiment, the powder 100 is less likely to adhere to the curtain 59, and the curtain 59 is made of a flexible material. No problem occurs even if the recoater 5 moving in the L direction and the curtain 59 come into contact with each other. Therefore, it is possible to provide a shielding portion capable of shielding the powder without using a complicated mechanism.

According to Embodiment 6, for example, 400 layers were modeled in a maximum area of 30 mm×40 mm to obtain a model with maximum dimensions of 30 mm×40 mm×20 mm. The modeling was completed without stopping, the rollers 7 were not damaged, and the shape accuracy of the three-dimensional model satisfied the predetermined standard. When the apparatus was checked before forming the powder layer in the middle of the modeling, there was almost no scattered matter (powder) originating from the powder for modeling on the surface of the recoater 5 . As described above, it is possible to prevent the scattered matter deposited on the recoater 5 from dropping into the modeling area, and it is possible to obtain a modeling apparatus with high stability in the modeling operation and excellent productivity.

As a modification of Embodiment 6, instead of using a one-piece curtain made of flexible material, a thin metal plate 35 as shown in FIGS. A metallic curtain connected by . As shown in a perspective view in FIG. 10(a) and a side view in FIG. 10(b), this curtain is formed by connecting thin metal plates 35 having holes for rivets with rivets 38. As shown in FIG. 10(a) and 10(b) show the state in which the curtain is not in contact with the recoater 5, that is, in the state in which it hangs vertically. The side view shown in FIG. 10(c) shows the state in which the curtain is in contact with the recoater 5, that is, the state in which it is bent under external force. By providing play by making the rivet hole larger than the shaft diameter of the rivet 38, it is possible to change the posture of the metal sheet 35 to some extent, so that the flexibility required for the curtain as a whole can be realized. can. Even if a member such as metal whose material itself has a small flexibility is used, by adopting such a connection method, it is possible to construct a curtain that has a shielding function and does not hinder the movement of the recoater. The metallic curtain is suitable for use when high durability is required for the curtain as a shielding part, or when an electron beam is used as the energy beam for heating the powder layer to create a vacuum in the chamber atmosphere. can be done.

[Other embodiments]
The present invention is not limited to the embodiments described above, and many modifications are possible within the technical concept of the present invention.
The type and arrangement of the mechanism for shielding the powder from reaching the recoater 5 are not limited to those exemplified in the above embodiment. For example, a shielding mechanism of the type illustrated in one embodiment may be placed in the location illustrated in another embodiment. The point is that the shielding portion can be arranged at a position that shields the trajectory of the powder that flies from the powder layer irradiated with the laser beam toward the recoater. The position that shields the trajectory of the powder flying toward the recoater is typically a position that shields the parabolic trajectory from the powder layer to the recoater. It may be a position that shields the trajectory of the powder.

Although the combination of silicon carbide powder and chromium diboride powder has been described in the embodiments, powders of other combinations may be used. It is not necessary to use the eutectic phenomenon as in the embodiment. For example, sublimable silicon carbide powder and metal powder may be used, and the molten metal may serve as a binder that binds silicon carbide together. Sublimable materials used as structural materials include silicon nitride (Si ₃ N ₄ ) and the like in addition to silicon carbide (SiC), and the present invention also applies to powder layers containing these sublimable materials. can exert the effect of In addition to chromium diboride (CrB ₂ ), zirconium boride (ZrB ₂ ), titanium boride (TiB ₂ ), vanadium boride (VB ₂ ), and the like are examples of materials that are eutectic with the sublimation material. Powder may be used. In addition, not only sublimable materials such as silicon carbide, but also resin powder and metal powder, depending on the irradiation conditions of the energy beam, the surrounding powder may scatter and adhere to the surface of the recoater due to bumping. effect can be expected.

The energy beam used for heating the powder layer is not limited to the laser beam, and may be other light beams or electron beams. The atmosphere in the chamber is not limited to the _N2 atmosphere, and may be appropriately changed according to the type of energy beam and powder material used. When an electron beam source is used as the energy beam source, the chamber is maintained in a vacuum atmosphere, so it is thought that the scattering of surrounding powder due to sublimation is greater than in atmospheric pressure, and a greater effect can be expected. .

1... Chamber/5... Recoater/6... Squeegee/7... Roller/8... Shield member/9... Shield plate/14... Scanning optical system/15... Laser oscillator/18... Powder layer/12... Laser beam/31... Solidified part/35... Metal thin plate/36... Sheet nozzle/38... Rivet/49... For shielding Top plate/59...Curtain/81...Joint/100...Powder/101...Protrusion/200...Three-dimensional modeling apparatus

Claims (18)

a powder layer forming unit for forming a powder layer;
an energy beam source for irradiating the powder layer formed by the powder layer forming unit with an energy beam;
a shielding part for shielding the powder scattered from the powder layer from reaching the powder layer forming part when the energy beam source irradiates the powder layer with the energy beam ; is modifiable and
When the energy beam source irradiates the powder layer with an energy beam, it takes an extended posture, and when the powder layer forming unit forms the powder layer, it takes a bent posture.
A three- dimensional modeling apparatus characterized by: a powder layer forming unit for forming a powder layer;
an energy beam source for irradiating the powder layer formed by the powder layer forming unit with an energy beam;
a shielding part for shielding the powder scattered from the powder layer from reaching the powder layer forming part when the energy beam source irradiates the powder layer with the energy beam ; is modifiable and
When the energy beam source irradiates the powder layer with the energy beam, the lower end is lower than the upper end of the powder layer forming section, and when the powder layer forming section forms the powder layer, the lower end is the powder layer forming section. above the top of the
A three-dimensional modeling apparatus characterized by: a powder layer forming unit for forming a powder layer;
an energy beam source for irradiating the powder layer formed by the powder layer forming unit with an energy beam;
a shielding portion that shields the powder scattered from the powder layer when the energy beam source irradiates the powder layer with an energy beam so as not to reach the powder layer forming portion;
The shielding part has flexibility,
A three- dimensional modeling apparatus characterized by: a powder layer forming unit for forming a powder layer;
an energy beam source for irradiating the powder layer formed by the powder layer forming unit with an energy beam;
a shielding portion that shields the powder scattered from the powder layer when the energy beam source irradiates the powder layer with an energy beam so as not to reach the powder layer forming portion;
The shielding part comprises a nozzle that supplies an airflow,
A three- dimensional modeling apparatus characterized by: a powder layer forming unit for forming a powder layer;
an energy beam source for irradiating the powder layer formed by the powder layer forming unit with an energy beam;
a shielding portion that shields the powder scattered from the powder layer when the energy beam source irradiates the powder layer with an energy beam so as not to reach the powder layer forming portion;
The shielding part drops the powder that has reached the shielding part,
A three- dimensional modeling apparatus characterized by: a powder layer forming unit for forming a powder layer;
an energy beam source for irradiating the powder layer formed by the powder layer forming unit with an energy beam;
a shielding portion that shields the powder scattered from the powder layer when the energy beam source irradiates the powder layer with an energy beam so as not to reach the powder layer forming portion;
Under the shielding part, a recovery mechanism for recovering powder scattered from the powder layer to the shielding part is provided,
A three- dimensional modeling apparatus characterized by: a powder layer forming unit for forming a powder layer;
an energy beam source for irradiating the powder layer formed by the powder layer forming unit with an energy beam;
a shielding portion that shields the powder scattered from the powder layer when the energy beam source irradiates the powder layer with an energy beam so as not to reach the powder layer forming portion;
The shielding part is provided above the powder supply part that stores the raw material powder,
A three- dimensional modeling apparatus characterized by: The powder layer forming unit is arranged at a standby position when the energy beam source irradiates the powder layer with an energy beam,
The shielding part is provided between the standby position and the powder layer,
The three-dimensional modeling apparatus according to any one of claims 1 to 7, characterized by: The shielding part can change its position or posture,
The shielding unit changes its position or posture when the energy beam source irradiates the powder layer with an energy beam and when the powder layer forming unit forms the powder layer,
The three-dimensional modeling apparatus according to any one of claims 3 to 7, characterized by: When the powder layer forming unit forms the powder layer, the shielding unit takes a position or posture that does not interfere with the powder layer forming unit,
The three-dimensional modeling apparatus according to any one of claims 1 to 7, characterized by: The shielding part is provided between the standby position and a powder supply part that stores the raw material powder,
The three-dimensional modeling apparatus according to claim 8, characterized by: The powder layer forming unit forms a powder layer containing a sublimable material,
The three-dimensional modeling apparatus according to any one of claims 1 to 11 , characterized by: wherein the sublimable material is silicon carbide;
The three-dimensional modeling apparatus according to claim 12 , characterized by: A method for manufacturing a three-dimensional structure in which a powder layer forming process by a powder layer forming unit and an energy beam irradiation process to the powder layer are repeatedly performed,
The shielding part shields the powder scattered from the powder layer in the energy beam irradiation process so that it does not reach the powder layer forming part,
In the energy beam irradiation process, the powder that has reached the shielding portion is dropped;
A method for manufacturing a three- dimensional structure, characterized by: The shielding part can change its position or posture,
The position or posture of the shielding part is changed by the powder layer forming process and the energy beam irradiation process,
The method for manufacturing a three-dimensional structure according to claim 14, characterized in that: In the powder layer forming process, the shielding part takes a position or posture that does not interfere with the powder layer forming part,
The method for manufacturing a three-dimensional structure according to claim 14 or 15, characterized in that: The powder layer forming process is a process of forming a powder layer containing a sublimable material.
The method for manufacturing a three-dimensional structure according to any one of claims 14 to 16 , characterized by: wherein the sublimable material is silicon carbide;
The method for manufacturing a three-dimensional structure according to claim 17 , characterized in that:

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