JP7305463B2 - 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 projections.

One aspect of the present invention includes 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 removes powder adhering to the powder layer forming unit. A three-dimensional modeling apparatus characterized by comprising a removing unit for

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, Manufacture of a three-dimensional structure, characterized in that after performing energy beam irradiation processing and before performing next powder layer forming processing, removing processing for removing powder adhering to the powder layer forming part is performed. The method.

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 projections.

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 a state in which a rotating brush roll is used to clean the right side surface of the recoater in the first embodiment. (c) A schematic diagram showing a state in which a rotating brush roll is used to clean the upper surface of the recoater in the first embodiment. (a) A schematic diagram showing a state at the end of cleaning in the first embodiment. (b) A schematic diagram showing one stage of the powder layer forming process after cleaning in the first embodiment. (c) A schematic diagram showing the next stage of the powder layer forming process after cleaning in Embodiment 1. FIG. (a) A schematic diagram showing the next step of the powder layer forming process after cleaning in Embodiment 1. FIG. (b) A schematic diagram showing a state in which the upper surface of the recoater is cleaned using a rotating brush roll in the second embodiment. (a) A schematic diagram showing a state in which the upper surface of the recoater is cleaned using a nozzle for blowing an air stream in the third embodiment. (b) A schematic diagram showing a state in which a scraper is used to clean the upper surface of the recoater in the fourth embodiment. (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 unit conveys powder from the powder supply tank 3 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 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 vicinity of the standby position of the recoater 5, a rotating brush roll 8 is provided as a removing section, which is a characteristic part of this embodiment. A rotating brush roll 8 serving as a removing unit is supported so as to move vertically and horizontally while rotating in order to remove scattered matter adhering to the surface of the recoater 5 . The rotating brush roll 8 used in this embodiment has a diameter of Φ18 mm, for example, and the brushes are made of fibers made of carbon, horse hair, or the like. The materials described above are used to suppress the generation of static electricity and damage to the recoater surface when the rotating brush roll 8 removes the scattered matter (powder) adhering to the surface of the recoater 5 . A collection container 9 for collecting the powder removed from the surface of the recoater 5 is arranged below the standby position of the recoater 5 . The operation of the rotating brush roll 8 will be detailed 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 this 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 required for powder spreading is carried to the left side of the modeling stage 2.

Subsequently, the recoater 5 whose posture is adjusted so that the lower end surface of the squeegee 6 is above the lowest part of the roller 7 is driven in the R direction to move the recoater 5 to the right side of the modeling stage 2 , and the roller 7 Powder is spread on the modeling stage 2 using a chisel.
Finally, after the modeling stage 2 is raised by 20 μm, the recoater 5 is driven in the L direction while the squeegee 6 is raised so that the lower end surface of the squeegee 6 is above the bottom of the rollers 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 this embodiment, after irradiation of a certain powder layer with the laser beam 12 is completed and before the next powder spreading process is started, the rotating brush roll 8 is used to remove the scattered matter adhering to the surface of the recoater 5. performs a characteristic operation of removing
In order to facilitate the understanding of this characteristic operation, the cause of unintentional formation of protrusions in the conventional apparatus when stacking solidified layers by repeating powder layer formation and laser beam irradiation will be investigated. The knowledge obtained by the inventor will be explained.

FIG. 6A 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. pay attention to.

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. 6( 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. 8 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. 9, the mechanism by which the powder around the portion irradiated with the laser beam scatters will be considered. As shown in FIG. 9, 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. 6(a), if the powder 100 adheres to the side surface of the recoater 5 or is stacked on the upper surface during laser irradiation, the recoater 5 will be unable to form the next powder layer after laser irradiation. , the powder 100 may fall.

FIG. 6(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 mounted on the top. As shown, the recoater 5 is driven in the R direction with the lower end of the squeegee 6 higher than the lowest part of the roller 7, 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. 7(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. 7(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

Therefore, in the present embodiment, after the irradiation of the powder layer with the laser beam 12 is completed, the scattered matter adhering to the surface of the recoater 5 is removed using the rotating brush roll 8 before the next powder spreading process is started. (Powder 100) is removed.

FIG. 2(a) schematically shows the state of the recoater 5 after irradiation with a laser beam as shown in FIG. 1 to form the solidified portion 31 constituting the three-dimensional structure. Powder 100 adheres to the top surface and right side surface of the recoater 5 at the standby position. The rotating brush roll 8 is positioned above the standby position of the recoater 5 .

In order to remove the scattered matter adhering to the surface of the recoater 5, first, as shown in FIG. 2(b), the rotary brush roll 8 is rotated and moved downward using the actuator. At this time, the rotational speed of the rotating brush roll 8 is, for example, 200 [rpm], and the rotating brush is moved downward while sliding on the right side surface of the recoater 5 (the front surface of the squeegee 6) to remove the adhering scattered matter (powder). 100) are removed. It is also possible to reciprocate the rotating brush roll 8 up and down multiple times.

After that, as shown in FIG. 2(c), the height of the rotating brush roll 8 is adjusted to the upper surface of the recoater 5, and a horizontal movement mechanism (for example, a rail) (not shown) is used to rotate the rotating brush roll 8 while L direction to remove the debris deposited on the top of the recoater 5 . It is also possible to reciprocate the rotating brush roll 8 left and right (L direction-R direction) multiple times.

Since the left side surface of the recoater 5 is a place where scattered matter does not adhere so much, it is often not necessary to use the removal process as described above. However, in the process of removing the scattered matter on the top of the recoater 5, it may adhere to the rear surface of the recoater 5, so after removing the scattered matter on the top of the recoater 5, rotate the rotating brush roll 8 along the left side surface. Scattered matter on the left side of the recoater 5 may be removed by moving downward.

The above-mentioned scattered object removal processing may be performed for each layer after irradiating the powder layer with the laser beam and before starting the next powder spreading, or it may be performed after repeating the laser beam irradiation and the powder spreading for a predetermined number of times. You can
In the above example, the right side surface of the recoater 5 is cleaned first, and then the top surface is cleaned, but the order of cleaning may be reversed.

In this embodiment, the scattered matter removed from the recoater 5 in the above process is collected in a collection container 9 as a collection unit. A dust collector (not shown) is connected to the collection container 9 so that the removed dust will not scatter again in the apparatus. The recovered powder may be reused as raw material powder for modeling.

FIG. 3(a) schematically shows the recoater 5 after cleaning by the rotating brush roll 8 has been completed and the adhering powder 100 has been removed. The rotating brush roll 8 is retracted to a position (upward) where it does not interfere with the recoater 5 .
After that, as shown in FIG. 3B, the powder supply stage 20 supporting the powder supply tank 3 is raised to push the powder upward, and the modeling stage 2 is lowered.
Then, as shown in FIG. 3(c), 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 lowest part of the roller 7. A large amount of powder is carried to the left side of the modeling stage 2.

Subsequently, as shown in FIG. 4( a ), 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 above the lowermost portion of the roller 7 . While the recoater 5 is moved to the right side of the modeling stage 2, only the roller 7 is used to spread powder on the modeling stage 2.例文帳に追加Furthermore, the recoater 5 is driven in the L direction to form a powder layer with a uniform thickness.

In the present embodiment, as shown in FIG. 4(a), the powder 100 attached to the recoater 5 is removed in advance before the powder 100 is moved on the modeling stage 2. Never let 100 fall and pile up.
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 the formation of the powder layer during modeling, there was almost no scattered matter (powder) originating from the powder for modeling on the surface of the recoater 5 after the cleaning operation. 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 2]
Embodiment 2 will be described with reference to FIG. The description of the parts common to the first embodiment is omitted. In the first embodiment, cleaning is performed by moving the rotating brush roll 8 as the removing section vertically and horizontally, but in the second embodiment, the position of the rotating brush roll 8 as the removing section is fixed. As shown in FIG. 4(b), the rotating brush roll 8 is fixed at a position where it can come into contact with the recoater 5, and when the recoater 5 moves in the R direction or the L direction during powder spreading, the rotating brush roll 8 is rotated to remove the scattered matter adhering to the recoater 5. - 特許庁The rotating brush roll 8 and the recoater 5 are in a slidable position when the powder spreading is started and when the recoater 5 returns to the standby position after finishing the powder spreading. objects are removed.

The rotation direction of the rotating brush roll 8 is preferably such that the direction in which the recoater 5 moves is counter to the direction in which the brush moves. Further, even if the rotating brush roll 8 is not actively rotated, the movement of the recoater 5 makes it possible to remove scattered matter to some extent. In this embodiment, it is difficult to remove the scattered matter adhering to the front and rear surfaces of the recoater 5, but the amount of the scattered matter adhering to the recoater 5 is overwhelmingly greater in the upper portion of the recoater 5, so the present embodiment is more effective than the conventional apparatus. Form can perform stable modeling.

In this embodiment, as shown in FIG. 4(b), the upper portion of the recoater 5 is provided with a recovery groove 21 as a recovery section for recovering the powder adhering to the surface. When cleaning the powder deposited on the recoater 5 while horizontally moving the recoater 5 using a fixed rotating brush roll 8, the powder is dropped and collected in a collection groove 21 having sufficient depth and capacity. The powder that has once entered the recovery groove does not drop outside from the recoater 5 during the powder layer forming operation. When the chamber is opened after molding, the powder accumulated in the collection groove 21 can be discharged by suction by connecting a dust cleaner to a nozzle connection port (not shown) provided near the collection groove 21 . Alternatively, during modeling or while the chamber is closed after modeling, an opening/closing shutter (not shown) provided at the bottom of the recovery groove is opened to drop the powder accumulated in the recovery groove 21 into, for example, the powder supply tank 3. You can reuse it.
In the example of FIG. 4(b), the recovery groove 21 and the recovery container 9 are used together, but either one of them may be used. Only the groove 21 may be provided.

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 the formation of the powder layer during modeling, there was almost no scattered matter (powder) originating from the powder for modeling on the surface of the recoater 5 after the cleaning operation. 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 3]
Embodiment 3 will be described with reference to FIG. The description of the parts common to the first embodiment is omitted. In Embodiment 1 or Embodiment 2, a rotating brush roller was used as a cleaner for removing the powder adhering to the surface of the recoater 5, but in this embodiment, a nozzle capable of blowing a gas stream is used as the removing unit. is different.

In this embodiment, an air stream is blown toward the recoater 5 to remove the powder adhering to the recoater 5 from the surface of the recoater. In the example shown in FIG. 5A, a removal nozzle 10 capable of ejecting inert gas is provided above the standby position of the recoater 5 . The gas blown out from the removal nozzle 10 is _N2 , the same as the atmosphere gas introduced into the chamber. The width (the depth direction in the drawing) of the opening of the nozzle from which _N2 is ejected is 400 mm, and the vertical width is 5 mm. For example, the jetting flow rate is set to 600 L/min, and the flow velocity of the jetting gas is adjusted to 5 m/s. N ₂ gas is blown from the removal nozzle 10 onto the top of the recoater 5 to remove the scattered matter deposited on the recoater 5 . In the case of the mixed powder of silicon carbide powder and chromium diboride powder used in this embodiment, the powder can be blown off at 5 m/s, but the flow rate and flow velocity may be appropriately changed according to the raw material powder used.

In this embodiment, after the powder layer is irradiated with the laser beam, the powder on the recoater 5 is removed by discharging N ₂ gas from the removal nozzle 10 while the recoater 5 is stationary at the standby position. However, the timing of discharging the N ₂ gas from the removal nozzle 10 is not limited to the above, and the N 2 gas may be blown during irradiation with the laser beam. Furthermore, as shown in the figure, when the recoater 5 is moving to the right (R direction) in the dusting operation, N ₂ gas is emitted from the removal nozzle 10 to remove the scattered matter deposited on the top of the recoater 5. Also good. The point is that the relative positional relationship should be such that the airflow can be blown over the entire upper surface of the recoater 5 .

In this embodiment, a recovery port 29 is provided on the left side of the recoater 5 as shown in FIG. A dust collector (not shown) is connected to the collection port 29 as a collection unit, so that scattered matter deposited on the recoater 5 is reliably collected.

In the form shown in FIG. 5(a), in this embodiment, it is difficult to remove the scattered matter adhering to the front and rear surfaces of the recoater 5, but the amount of the scattered matter adhering to the recoater 5 is overwhelmingly the upper portion of the recoater 5. Therefore, the present embodiment can form more stably than the conventional apparatus.
It should be noted that although the device configuration is somewhat complicated, the blowing direction of the removing nozzle 10 may be changed so that the front surface (right side surface) of the recoater 5 can also be sprayed. In that case, in addition to the recovery port 29, it is desirable to provide the recovery container 9 as in the first embodiment.

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 the predetermined standard. When the apparatus was checked before the formation of the powder layer during modeling, there was almost no scattered matter (powder) originating from the powder for modeling on the surface of the recoater 5 after the cleaning operation. 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 4]
Embodiment 4 will be described with reference to FIG. 5(b). The description of the parts common to the first embodiment is omitted. In Embodiment 1 or 2, a rotating brush roller is used as a cleaner for removing powder adhering to the surface of the recoater 5, and in Embodiment 3, a nozzle for blowing a gas stream is used. The difference is that a scraper 22 is used as a
In this embodiment, the upper surface of the recoater 5 and the scraper are slid to remove the powder adhering to the recoater 5 from the surface of the recoater.

In this embodiment, after the powder layer is irradiated with the laser beam, while the recoater 5 is stationary at the standby position, the scraper 22 is horizontally moved to slide the upper surface of the recoater 5 to remove the powder on the recoater 5. . However, the sliding timing is not limited to the above, and the sliding may be performed while the laser beam is being irradiated. Furthermore, as shown in the figure, when the recoater 5 moves to the right (R direction) in the dusting operation, the scraper 22 may be brought into contact with the recoater 5 to remove scattered matter deposited on the top of the recoater 5 . The point is that the scraper 22 should be relatively moved so as to slide over the entire upper surface of the recoater 5 .

In this embodiment, a recovery groove 21 is provided in the upper portion of the recoater 5 as a recovery section for recovering the powder adhering to the surface. The powder is dropped and recovered in a recovery groove 21 having sufficient depth and capacity. The powder that has once entered the recovery groove does not drop outside from the recoater 5 during the powder layer forming operation. When the chamber is opened after molding, the powder accumulated in the collection groove 21 can be discharged by suction by connecting a dust cleaner to a nozzle connection port (not shown) provided near the collection groove 21 . Alternatively, during modeling or while the chamber is closed after modeling, an opening/closing shutter (not shown) provided at the bottom of the recovery groove is opened to drop the powder accumulated in the recovery groove 21 into, for example, the powder supply tank 3. You can reuse it.

In this embodiment, it is difficult to remove the spattered matter adhering to the front and rear surfaces of the recoater 5, but the amount of spattered matter adhering to the recoater 5 is overwhelmingly greater in the upper portion of the recoater 5, so the present apparatus is superior to the conventional apparatus. The embodiment has the advantage of being able to perform more stable modeling.
It should be noted that the scraper 22 may be provided with a vertical movement mechanism, and the front surface (right side surface) of the recoater 5 may also be slidable, although this will result in a somewhat complicated apparatus configuration. In that case, in addition to the recovery groove 21, it is desirable to provide the recovery container 9 as in the first embodiment.

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 modeling, there was almost no scattered matter (powder) originating from the powder for modeling on the surface of the recoater 5 after the cleaning operation. 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.

[Other embodiments]
The present invention is not limited to the embodiments and examples described above, and many modifications are possible within the technical concept of the present invention.
The method of removing the powder adhering to the recoater 5 is not limited to the exemplified method using a rotating brush roll, the method using an air stream, or the method using a scraper. For example, the surface of the recoater 5 may be vibrated using an ultrasonic vibration device or the like to shake off the powder adhering to the surface of the recoater 5 . A non-rotating brush or a flexible member such as a sponge may be used.

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. A 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... Rotating brush roll/10... Removal nozzle/14... Scanning optical system/15... Laser oscillator/18 Powder layer/12 Laser beam/22 Scraper/31 Solidified portion/100 Powder/101 Projection/200 Tertiary Original molding device

Claims (20)

a powder layer forming unit that forms a powder layer by moving over the powder layer with respect to the powder layer ;
an energy beam source for irradiating the powder layer formed by the powder layer forming unit with an energy beam;
A removing unit positioned above the height at which the powder layer is formed and removing the powder adhering to the powder layer forming unit,
A three-dimensional modeling apparatus characterized by: The removing unit removes the powder deposited on the powder layer forming unit,
The three-dimensional modeling apparatus according to claim 1, characterized by: The removing unit contacts the powder layer forming unit ,
The three-dimensional modeling apparatus according to claim 1 or 2, characterized by: The removing unit moves relative to the powder layer forming unit ,
The three-dimensional modeling apparatus according to claim 3, characterized by: The removing unit has a brush that can slide on the surface of the powder layer forming unit,
The three-dimensional modeling apparatus according to any one of claims 1 to 4, characterized in that: 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;
and a removing unit for removing powder adhering to the powder layer forming unit,
The removing unit has a nozzle capable of generating an airflow on the surface of the powder layer forming unit,
A three- dimensional modeling apparatus characterized by: The removing unit has a scraper that can slide on the surface of the powder layer forming unit,
The three-dimensional modeling apparatus according to any one of claims 1 to 4, characterized in that: The removing unit has a recovery unit that recovers the powder removed from the powder layer forming unit,
The three-dimensional modeling apparatus according to any one of claims 1 to 7, 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,
In the forming process, the powder layer forming unit moves over the powder layer with respect to the powder layer,
After performing the energy beam irradiation treatment and before performing the next powder layer forming treatment, the removal portion located above the height at which the powder layer is formed removes the powder adhering to the powder layer forming portion. perform a removal process to remove the
A method for manufacturing a three-dimensional structure, 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,
In the forming process, the powder layer forming unit moves over the powder layer with respect to the powder layer,
After performing the energy beam irradiation treatment and before performing the next powder layer forming treatment, performing a removal treatment for removing the powder deposited in the powder layer forming part,
A method for manufacturing a three-dimensional structure, 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,
After performing the energy beam irradiation process and before performing the next powder layer forming process, the powder scattered from the powder layer and adhering to the powder layer forming portion during the energy beam irradiation process is removed. perform a removal process to remove,
A method for manufacturing a three-dimensional structure, 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,
After performing the energy beam irradiation process and before performing the next powder layer forming process, performing a removing process of removing the powder adhering to the powder layer forming part with an air flow,
A method for manufacturing a three-dimensional structure, characterized by : The powder layer forming unit moves over the powder layer ,
The method for manufacturing a three-dimensional structure according to claim 11 or 12 , characterized in that: The removal process is performed each time the energy beam irradiation process is performed, or
After repeating the powder layer forming process and the energy beam irradiation process a predetermined number of times, the removing process is performed before the next powder layer forming process.
The method for manufacturing a three-dimensional structure according to any one of claims 9 to 13, 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 9 to 14 , characterized in that: The powder layer forming process is a process of forming a powder layer containing silicon carbide.
The method for manufacturing a three-dimensional structure according to any one of claims 9 to 15, characterized in that: The removal process is a process of sliding a brush on the surface of the powder layer forming part.
The method for manufacturing a three-dimensional structure according to any one of claims 9 to 11 , characterized in that: The removal process is a process of blowing airflow toward the surface of the powder layer forming part.
The method for manufacturing a three-dimensional structure according to claim 9 , 10 or 12, characterized in that: The removal process is a process of sliding a scraper on the surface of the powder layer forming part.
The method for manufacturing a three-dimensional structure according to any one of claims 9 to 11 , characterized in that: recovering the powder removed from the powder layer forming part in the removal process;
The method for manufacturing a three-dimensional structure according to any one of claims 9 to 19 , characterized in that:

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