JP2024054693A - Layered modeling device, method for manufacturing three-dimensional object, and teaching method - Google Patents

Abstract

[Problem] To provide an additive manufacturing device, a manufacturing method for a three-dimensional object, and a teaching method, which enable unmanned removal of a model by more effectively removing excess material on a modeling table. [Solution] An additive manufacturing device 100 includes a modeling table 4, a chamber 1, a material layer forming device 2, a chuck device 5, a material recovery device 7, a transport robot 6, a mobile robot 8, and a control device. The chuck device 5 detachably fixes a base plate on the modeling table 4, the material recovery device 7 includes a suction nozzle 79, the mobile robot 8 is capable of moving the suction nozzle 79, and the control device alternately repeats raising the modeling table 4 by a predetermined lift amount and controlling the mobile robot 8 to move the suction nozzle 79 according to teaching data to suck up the excess material powder, the teaching data including a moving path and a posture of the suction nozzle 79 corresponding to the shape of the model and the height of the modeling table 4. [Selected Figure] FIG.

Description

The present invention relates to an additive manufacturing device, a method for manufacturing a three-dimensional object, and a teaching method.

Various methods are known for additive manufacturing of three-dimensional objects. For example, an additive manufacturing device that performs powder bed fusion places a base plate in a modeling area on a modeling table arranged in a chamber, supplies material powder to the modeling area to form a material layer, and irradiates a laser beam or electron beam at a predetermined position on the material layer to sinter or melt the material powder to form a solidified layer. By repeatedly forming material layers and solidified layers, solidified layers are stacked on the base plate, and cutting is performed by a cutting means during or after modeling as necessary to produce the desired three-dimensional object.

In additive manufacturing using powdered material, such as powder bed fusion, not all of the powdered material delivered to the build area solidifies. After building, unsolidified powdered material remains on and around the object, base plate, and build table, and excess material must be removed when the object is removed from the chamber.

As disclosed in Patent Document 1, it is known that an additive manufacturing device is provided with a suction nozzle for sucking and removing excess material. Before removing the molded object, an operator operates the suction nozzle to suck up the excess material, and the excess material is removed. In such additive manufacturing devices, there is a demand for automatically removing the molded object from the chamber after molding. For example, when performing secondary processing on the molded object, it is desirable to automatically perform a series of steps of removing the molded object from the additive manufacturing device and sending the removed molded object to a secondary processing device. When automatically removing the molded object from the chamber, it is necessary to automatically remove the excess material after molding. Patent Document 2 discloses a configuration in which the excess material remaining after molding is automatically removed by a suction nozzle.

Patent No. 6132962 JP 2002-205339 A

In conventional additive manufacturing devices that automatically remove excess material by suction, such as that shown in Patent Document 2, it is often the case that excess material remaining around the base plate, modeling table, and modeling plate, including excess material that has entered into depressions and grooves formed in the model, cannot be fully removed. If excess material remains on the modeling table, it adversely affects the high-precision positioning when placing a replacement base plate or pallet on the modeling table for the next modeling and the reuse of material powder, so the model cannot be removed unless the excess material is removed by hand, which hinders automation in removing and transporting the modeled object.

The present invention was made in consideration of these circumstances, and aims to provide an additive manufacturing device, a manufacturing method for a three-dimensional object, and a teaching method that enable unmanned removal of the object by more efficiently removing excess material on the modeling table.

According to the present invention, the following inventions are provided.
[1] An additive manufacturing apparatus including a modeling table, a chamber, a material layer forming device, a chuck device, a material recovery device, a transport robot, a moving robot, and a control device, wherein the modeling table is configured to be movable up and down by a table drive mechanism, the chamber covers a modeling area provided on the modeling table where a model is formed, the material layer forming device supplies material powder onto a base plate placed in the modeling area to form a material layer, the chuck device is disposed on the modeling table and configured to be able to detachably and fix the base plate within the modeling area, and the material recovery device recovers the material powder from the surplus material on the modeling table. the transport robot is configured to be able to remove the base plate and the modeled object modeled on the base plate from the chamber, the mobile robot is configured to be able to move the suction nozzle, and the control device alternately repeats controlling the table drive mechanism to raise the modeling table by a predetermined lift amount and controlling the mobile robot in accordance with teaching data to move the suction nozzle while sucking up the excess material powder, and the teaching data includes a movement path and attitude of the suction nozzle that correspond to the shape of the modeled object and the height of the modeling table.
[2] An additive manufacturing apparatus as described in [1], comprising an imaging device configured to acquire images of an area including at least the base plate and the object, and the control device determines whether or not there is excess material powder using the images acquired by the imaging device.
[3] An additive manufacturing apparatus as described in [1] or [2], comprising a detection means capable of detecting the proportion of the material powder in the object to be sucked by the suction nozzle, and the control device determines whether or not there is surplus material powder based on the proportion of the material powder.
[4] The additive manufacturing apparatus according to [3], wherein the detection means is a flow rate sensor.
[5] An additive manufacturing apparatus according to any one of [1] to [4], comprising: a powder retaining wall surrounding the modeling table and configured to retain the material powder on the modeling table; and a material recovery bucket configured to accommodate excess material powder discharged outside the powder retaining wall, wherein the material recovery apparatus has an operation mode including a recovery mode and a suction mode, and the control device is configured to switch between the operation modes. In the recovery mode, the material recovery apparatus recovers the material powder in the material recovery bucket, removes impurities, and supplies the material powder to the material layer forming device, and in the suction mode, the suction nozzle is moved by the mobile robot to suck up the excess material powder on the modeling table through the suction nozzle, and removes impurities from the material powder.
[6] An additive manufacturing apparatus according to any one of [1] to [5], wherein a side of the chuck device is covered by a chuck cover, the chuck cover having an outer cover and an inner cover, the outer cover covers at least a portion of the side of the inner cover, and the inner cover covers the side of the chuck device.
[7] An additive manufacturing apparatus according to any one of [1] to [6], wherein the chuck device fixes the base plate via a mounting plate.
[8] An additive manufacturing apparatus according to any one of [1] to [7], wherein the suction nozzle is provided with a suction portion at a tip end thereof, the suction portion has a cylindrical shape with an end face at the tip end cut by an inclined surface, and an opening is provided on the inclined surface.
[9] An additive manufacturing apparatus according to any one of [1] to [8], wherein the transport robot is configured to be capable of transporting the base plate into the chamber.
[10] An additive manufacturing apparatus according to any one of [1] to [9], wherein the transport robot is configured to invert the object after removing it from the chamber.
[11] A method for manufacturing a three-dimensional object, comprising: a placing step, a solidified layer forming step, a suction step, and a removal step, wherein in the placing step, a base plate is detachably fixed by a chuck device arranged on a modeling table, thereby placing the base plate in a modeling area on the modeling table, which is an area where a model is formed, and in the solidified layer forming step, a material layer forming step of supplying material powder onto the base plate to form a material layer, and a solidification step of irradiating a predetermined irradiation area of the material layer with a laser beam or an electron beam are repeated to form a solidified layer. a suction step alternately repeating raising the modeling table by a predetermined amount using a table driving mechanism and suctioning the excess material powder while moving a suction nozzle using a mobile robot in accordance with teaching data; and a removal step alternately repeats removing the base plate and the modeled object modeled on the base plate from a chamber covering the modeling area using a transport robot, the teaching data including a movement path and posture of the suction nozzle corresponding to the shape of the modeled object and the height of the modeling table.
[12] A teaching method for acquiring teaching data used when suctioning excess material powder generated in additive manufacturing of a three-dimensional object with a suction nozzle, the teaching method comprising: a placing step, a modeling step, a recording step, and a lifting step; in the placing step, a base plate is detachably fixed by a chuck device arranged on a modeling table, so that the base plate is placed in a modeling area on the modeling table, which is an area where a model is formed; in the modeling step, a material layer forming step of supplying material powder onto the base plate to form a material layer; and a laser beam or laser beam irradiating a predetermined irradiation area of the material layer. a solidification process in which a solidified layer is formed by irradiating an electron beam to the solidified layer, and a recording process in which the solidified layers are stacked to form a three-dimensional object; in the recording process, a mobile robot is manually operated to move the suction nozzle while sucking up the excess material powder on the modeling table, and the position coordinates and attitude of the suction nozzle are recorded; in the lifting process, the modeling table is lifted by a predetermined lift amount; and by repeating the recording process and the lifting process, the teaching data including the movement path and attitude of the suction nozzle corresponding to the shape of the modeled object and the height of the modeling table are obtained.

The additive manufacturing device according to the present invention is provided with a suction nozzle that can be moved by a mobile robot, and while gradually raising the modeling table, the suction nozzle is moved in accordance with teaching data to suction and remove excess material. The teaching data includes an optimal movement path and posture of the suction nozzle that corresponds to the shape of the model and the height of the modeling table, which allows excess material on the modeling table to be removed more reliably and efficiently. In this case, the removal of excess material by the suction nozzle is performed automatically, making it possible to remove the model without human intervention.

1 is a schematic configuration diagram of an additive manufacturing apparatus 100 according to an embodiment of the present invention. FIG. 2 is a perspective view of a material layer forming device 2 of the additive manufacturing apparatus 100. 2 is a perspective view of a recoater head 22 of the material layer forming apparatus 2 from above. 2 is a perspective view of a recoater head 22 of the material layer forming apparatus 2, seen from below. 13 is a perspective view showing a state in which a base plate 83 is fixed to a chuck device 5. FIG. 6 is a cross-sectional view taken along line AA in FIG. 5. 1 is a perspective view showing a pallet 85, a positioning plate 86, and a shaft 87 in an exploded state. 2 is a perspective view showing a state in which a chuck cover 53 is removed from the chuck device 5. FIG. 9A and 9B are diagrams showing the tip of the suction portion 79a of the suction nozzle 79. Fig. 9A is a front view, and Fig. 9B is a right side view. 13 is a diagram for explaining a manner in which excess material of an excess material layer 81a is suctioned by a suction nozzle 79. FIG. FIG. 2 is a configuration diagram of a control device 9 of the additive manufacturing apparatus 100. 1 is a flow diagram of a method for manufacturing a three-dimensional object W using the additive manufacturing device 100. FIG. FIG. 1 is a flow diagram of a teaching method for obtaining teaching data. 1A to 1C are diagrams for explaining a method for manufacturing a three-dimensional object W using the additive manufacturing device 100. FIG. 11 is a diagram for explaining a solidified layer forming step. FIG. 11 is a diagram for explaining a suction process.

The following describes an embodiment of the present invention with reference to the drawings. The features of the following embodiment can be combined with each other. Each feature can also be used as an invention independently.

1. Additive manufacturing device 100
1 is a schematic diagram of an additive manufacturing apparatus 100 according to this embodiment. The additive manufacturing apparatus 100 includes a chamber 1, a material layer forming device 2, an irradiation device 3, a modeling table 4, a chuck device 5, a transfer robot 6, a material recovery device 7, a mobile robot 8, an imaging device 18, and a control device 9. In a modeling region R provided on the modeling table 4 arranged in the chamber 1, a material layer 81 and a solidified layer 82 are repeatedly formed to form a desired three-dimensional object W.

1.1. Chamber 1
The chamber 1 covers a printing region R where a desired three-dimensional object W is to be formed. The inside of the chamber 1 is filled with a predetermined concentration of inert gas supplied from an inert gas supply device (not shown). In this specification, the inert gas is a gas that does not substantially react with the material layer 81 or the solidified layer 82, and is selected according to the type of material. For example, nitrogen gas, argon gas, or helium gas can be used. The inert gas containing fumes generated during the formation of the solidified layer 82 is exhausted from the chamber 1, and after the fumes are removed in a fume collector (not shown), it is supplied to the chamber 1 and reused. The fume collector is, for example, an electric dust collector or a filter.

A window 1a that serves as a transmission window for laser light B is provided on the upper surface of the chamber 1. The window 1a is made of a material that can transmit laser light B. Specifically, the material of the window 1a is selected from quartz glass, borosilicate glass, or crystals of germanium, silicon, zinc selenide, or potassium bromide, depending on the type of laser light B. For example, when the laser light B is a fiber laser or a YAG laser, the window 1a can be made of quartz glass.

A contamination prevention device 17 is provided on the upper surface of the chamber 1 so as to cover the window 1a. The contamination prevention device 17 comprises a cylindrical housing 17a and a cylindrical diffusion member 17b arranged inside the housing 17a. The clean inert gas supplied to the space between the housing 17a and the diffusion member 17b fills the inside of the diffusion member 17b through pores formed in the wall surface of the diffusion member 17b, and is further ejected downward through an opening provided in the bottom surface of the housing 17a. This configuration makes it possible to prevent fumes from adhering to the window 1a and to remove fumes from the irradiation path of the laser light B.

The chamber 1 is also provided with a work door (not shown) that can be opened and closed under the control of the control device 9. When the base plate 83 is loaded into the chamber 1, or when the base plate 83 and the model W are removed from the chamber 1, the work door is opened and the transport robot 6 enters and exits the chamber 1 to perform the loading and unloading operations. When loading and unloading operations are not being performed, particularly during modeling, the work door is closed.

1.2. Material layer forming device 2
The material layer forming apparatus 2 supplies material powder onto a base plate 83 placed in the modeling region R to form a material layer 81. As shown in FIGS. 1 to 4, the material layer forming apparatus 2 The recoater head 22 is provided inside the chamber 1 and is arranged on the base 21. The recoater head 22 is configured to be reciprocated in one horizontal axial direction by a recoater head driving device 23. will be done.

3 and 4, the recoater head 22 includes a material storage section 22a, a material supply port 22b, and a material discharge port 22c. The material supply port 22b is provided on the upper surface of the material storage section 22a, has a rectangular shape extending in the longitudinal direction of the material storage section 22a, and serves as a receiving port for the material powder supplied from the material supply unit 10 to the material storage section 22a. The material discharge port 22c is provided on the bottom surface of the material storage section 22a, and discharges the material powder in the material storage section 22a. The material discharge port 22c has a slit shape extending in the longitudinal direction of the material storage section 22a. Flat blades 22fb and 22rb are provided on both side surfaces of the recoater head 22. The blades 22fb and 22rb flatten the material powder discharged from the material discharge port 22c to form a material layer 81.

1.3. Irradiation device 3
As shown in Fig. 1, the irradiation device 3 is provided above the chamber 1. The irradiation device 3 irradiates an irradiation region of a material layer 81 formed in a modeling region R with a laser beam B to produce a material powder. The material powder is melted or sintered to be solidified, forming a solidified layer 82. The laser beam B may be any type capable of melting or sintering the material powder, and may be, for example, a fiber laser, a _CO2 laser, or a YAG laser. The irradiation device 3 may be configured to irradiate the material layer 81 with an electron beam instead of the laser light B to solidify the material layer 81 .

1.4. Modeling table 4
The modeling table 4 is provided in the chamber 1, and a modeling region R is provided on the upper surface of the modeling table 4. The modeling table 4 is configured to be movable up and down by a table driving mechanism 41. The table driving mechanism 41 in this embodiment is configured using a motor as a driving source. Note that the configuration of the table driving mechanism 41 is not limited to the example of this embodiment, and other forms may be used as long as the modeling table 4 can be moved up and down (vertically).

1.5. Chuck device 5
The chuck device 5 is disposed on the molding table 4, and is configured to be able to detachably and fix the base plate 83 within the molding region R. The chuck device 5 holds and fixes the base plate 83, whereby the base plate 83 is placed within the molding region R.

The base plate 83 may be fixed directly by the chuck device 5, or may be fixed via a separate member such as the mounting plate 84. In this embodiment, as shown in Figs. 1, 5, and 6, the base plate 83 is detachably fixed by the chuck device 5 via the mounting plate 84 and the pallet 85. Specifically, a shaft 87 is attached to the bottom surface of the pallet 85 so as to protrude downward, and the pallet 85 is detachably fixed by gripping the shaft 87 with the chuck device 5. The mounting plate 84 is fixed on the pallet 85 using a fixing member such as a bolt, and the base plate 83 is fixed on the mounting plate 84 using a fixing member such as a bolt. In other words, the chuck device 5, the pallet 85, the mounting plate 84, and the base plate 83 are arranged in this order from the bottom, and the three-dimensional object W is formed on the upper surface of the base plate 83.

As shown in Figures 6 to 8, the chuck device 5 of this embodiment includes a chuck base 51 arranged on the modeling table 4 and a clamp unit 52 arranged on the chuck base 51.

The chuck base 51 is used to fix the chuck device 5 onto the modeling table 4. In this embodiment, the four corners of the chuck base 51, which is rectangular in plan view, are fixed to the modeling table 4 by fixing members such as bolts.

The clamp unit 52 has a generally cylindrical shape with a bottom. The upper surface of the clamp unit 52 is provided with a plurality of first protrusions 52a and a plurality of second protrusions 52b (four in one example) that are concentric in a plan view, and further provided with a plurality of abutment recesses 52c (four in one example) that are formed radially from the center in a plan view. Inside the clamp unit 52, as shown in FIG. 6, a plurality of balls 52d are arranged at equal intervals along the circumferential direction of the shaft 87 as locking members that lock the shaft 87.

As shown in Figures 6 and 7, the shaft 87 includes a chucking plug 87a and a locking portion 87b provided on the outside of the chucking plug 87a. A threaded portion is formed on the upper end side of the chucking plug 87a, and the chucking plug 87a is attached to the pallet 85 by screwing the threaded portion into a screw hole formed in the bottom surface of the pallet 85. The lower end of the chucking plug 87a is inserted into the insertion hole 52e of the clamp unit 52, and the ball 52d of the clamp unit 52 engages with the recess 87c of the locking portion 87b, thereby locking the shaft 87. This fixes the pallet 85 to the chuck device 5.

Furthermore, in this embodiment, a positioning plate 86 is interposed between the pallet 85 and the clamp unit 52. The positioning plate 86 is fixed to the bottom surface of the pallet 85 using a fixing member such as a bolt. The positioning plate 86 is provided with a plurality of first openings 86a and second openings 86b (four in one example). The first openings 86a and second openings 86b are provided at positions that overlap the first convex portion 52a and the second convex portion 52b of the clamp unit 52, respectively, in a plan view, and the positioning plate 86 is positioned in the horizontal direction by inserting the first convex portion 52a into the first opening 86a and the second convex portion 52b into the second opening 86b.

In addition, a number of (four in one example) support feet 86c are attached to the underside of the positioning plate 86 using mounting shafts 86d. The support feet 86c are attached at positions that overlap the abutment recesses 52c in a plan view, and the positioning plate 86 is positioned in the vertical direction when the bottom surfaces of the support feet 86c abut against the abutment recesses 52c. By attaching the positioning plate 86 to the pallet 85, when the pallet 85 is fixed by the chuck device 5, the mounting plate 84 and base plate 83 fixed on the pallet 85 can be positioned at predetermined positions in the horizontal and vertical directions with high precision.

In this embodiment, the base plate 83 is fixed to the chuck device 5 via separate members (mounting plate 84 and pallet 85). In this configuration, mounting parts such as screw holes for mounting the shaft 87 and positioning plate 86 can be formed in the separate members, and the separate members can be partially or completely removed from the base plate 83 after molding and reused. Therefore, since there is no need to provide mounting parts on the base plate 83 depending on the shape of the chuck device 5, the base plate 83 can be manufactured more inexpensively.

As shown in Figures 5 and 6, in this embodiment, the side of the chuck device 5 is covered by a chuck cover 53. The chuck cover 53 includes an outer cover 54 and an inner cover 55. The outer cover 54 covers at least a portion of the side of the inner cover 55, and the inner cover 55 covers the side of the chuck device 5. The material of the chuck cover 53 can be metal, resin, or the like.

6 and 8, the inner cover 55 has a cylindrical inner covering portion 55a and a flange portion 55b that protrudes radially outward at the lower end of the inner covering portion 55a. The inner covering portion 55a covers the side surface of the clamp unit 52 of the chuck device 5. The inner cover 55 is fixed to the chuck base 51 at the flange portion 55b. The outer cover 54 has a cylindrical outer covering portion 54a and an upper surface portion 54b that protrudes radially inward at the upper end of the outer covering portion 54a. The outer covering portion 54a covers an upper part of the side surface of the inner covering portion 55a. The outer cover 54 is fixed to the pallet 85 with the upper surface of the upper surface portion 54b in contact with the bottom surface of the pallet 85 at the upper surface portion 54b. The outer cover 54 and the inner cover 55 are arranged so that the outer covering portion 54a and the inner covering portion 55a are coaxial. This configuration makes it possible to prevent excess material from entering the inside of the chuck device 5, particularly the clamp unit 52, when the base plate 83 is released from the chuck device 5 during or after modeling is completed.

As shown in FIG. 6, a gap G is provided between the outer cover 54 and the inner cover 55. Specifically, the outer cover 54 and the inner cover 55 are designed so that the inner diameter D1 of the outer covering portion 54a and the outer diameter D2 of the inner covering portion 55a satisfy the condition D1>D2, thereby providing the gap G. The gap G is preferably provided so that the distance between the inner surface of the outer covering portion 54a and the outer surface of the inner covering portion 55a (in this embodiment, (D1-D2)/2) is 1 to 10 mm. In this configuration, the path through which powder such as excess material that has fallen from the base plate 83 reaches the inside of the chuck cover 53 is bent, so that the intrusion of the powder can be more effectively prevented.

The configuration of the chuck cover 53 is not limited to the example of this embodiment. For example, the inner covering portion 55a and the outer covering portion 54a may be rectangular tubular. According to the embodiment of the chuck device 5 shown in Figures 6 to 8, regardless of the process by which the transfer robot 6 sucks and removes the excess material powder, the risk of a situation occurring in which it becomes impossible to continue modeling due to the excess material powder entering the clamp unit 52 is reduced, thereby supporting unmanned operation of continuous modeling.

1.6. Transport robot 6
The transfer robot 6 is configured to be able to remove the base plate 83 and the object W formed on the base plate 83 from the chamber 1. In this embodiment, after the completion of modeling, the balls 52d of the clamp unit 52 are disengaged from the recesses 87c to release the fixation of the pallet 85 by the chuck device 5. In this state, the transfer robot 6 grips a predetermined portion of the pallet 85 or inserts a support rod into a support hole (not shown) provided on the side of the pallet 85 to lift it up, thereby removing the base plate 83 and the object W together with the mounting plate 84, the pallet 85, the shaft 87, and the outer cover 54 from the chamber 1 via the work door.

The transport robot 6 may be configured to move the object W to a predetermined position after removing it from the chamber 1 and to invert the object W upside down. By inverting the object W, excess material adhering to the object W and the base plate 83 can be dropped and removed. At this time, the inverted object W may be placed on a finishing device (not shown) provided outside the chamber 1, and the excess material may be automatically or manually removed for finishing. Examples of methods for finishing include sucking the material powder with a suction nozzle, vibrating the object W to cause the material powder to fall, or transporting the object W to a suction chamber (not shown) outside the chamber 1 to remove the powder by suction.

When performing secondary processing on the object W, the transfer robot 6 removes the base plate 83 and the object W from the chamber 1 and moves them to a secondary processing device (not shown).

The transport robot 6 in this embodiment is also used to transport the base plate 83 into the chamber 1 before the start of modeling. Specifically, the base plate 83, mounting plate 84, pallet 85, shaft 87, and outer cover 54 are stored as an integrated base plate set in a stocker (not shown) provided outside the chamber 1, and the transport robot 6 transports the base plate set into the chamber 1 through the work door by gripping a predetermined portion of the pallet 85 or by inserting a support rod into a support hole provided on the side of the pallet 85 and lifting it up, and inserts the lower end of the shaft 87 into the clamp unit 52. The pallet 85 is fixed by the chuck device 5 by engaging the ball 52d with the recess 87c of the inserted shaft 87.

1.7. Material Powder Supply/Recovery System Next, a material powder supply/recovery system including the material recovery device 7 will be described. As shown in Fig. 1, a material supply unit 10 is provided near the wall surface of the chamber 1. The material supply unit 10 includes a material tank 11, a main duct 12, and an intermediate duct 13. New material powder is stored in the material tank 11, and is supplied to the intermediate duct 13 through the main duct 12.

The intermediate duct 13 is configured to be movable in the vertical direction and to discharge the material powder from the intermediate duct outlet 13a. In this embodiment, the intermediate duct outlet 13a is rectangular and extends in approximately the same direction as the material supply port 22b of the recoater head 22. The intermediate duct outlet 13a is configured to be openable and closable by the shutter 14. The intermediate duct outlet 13a is normally closed by the shutter 14. When refilling the material powder, the recoater head 22 moves directly below the intermediate duct 13, and the intermediate duct 13 moves so that the intermediate duct outlet 13a is lower than the upper end of the material storage section 22a. In this state, the shutter 14 opens and the material powder is refilled.

In this embodiment, a powder retaining wall 42 is provided to surround the modeling table 4. The powder retaining wall 42 retains the material powder on the modeling table 4. In addition, a material recovery bucket 70 is provided that is configured to receive excess material discharged outside the powder retaining wall 42.

At least one powder discharge section 70b communicating with the material recovery bucket 70 is provided on the base 21 of the material layer forming device 2. Excess material and impurities pushed out by the moving recoater head 22 are discharged from the powder discharge section 70b, guided to the shooter 70e by the shooter guide 70d, and stored in the material recovery bucket 70. The powder discharge section 70b may be configured to be openable and closable by a shutter (not shown). Furthermore, a powder discharge section 70a capable of discharging the material powder inside the powder holding wall 42 may be provided below the powder holding wall 42, and a part of the impurities such as unsolidified material powder and cutting chips may be discharged from the powder discharge section 70a by lowering the modeling table 4 after the completion of the layered modeling. In this case, the material powder discharged from the powder discharge section 70a is guided to the shooter 70e by the shooter guide 70c, and stored in the material recovery bucket 70.

As shown in FIG. 1, the material recovery device 7 of this embodiment includes a material recovery transport device 71, an impurity removal device 73, a suction device 74, a material supply bucket 76, a material drying device 77, a material supply transport device 78, and a suction nozzle 79. The suction port 71b of the material recovery transport device 71 is connected to the material recovery bucket 70 by piping or the like via a switching valve 72, and the material powder containing impurities in the material recovery bucket 70 is transported to the impurity removal device 73 by the material recovery transport device 71. Examples of impurities include sputters generated during irradiation and processing chips generated by cutting processing. The impurity removal device 73 removes impurities from the material powder transported from the material recovery transport device 71. The material powder from which the impurities have been removed is stored in the material supply bucket 76. The material drying device 77 dries the material powder in the material supply bucket 76. The material powder dried by the material drying device 77 is supplied into the main duct 12 by a material supply conveying device 78 connected to the top of the main duct 12 and reused.

The material recovery transport device 71 and the material supply transport device 78 have a cyclone type filter inside, and the exhaust port 71a and the exhaust port 78a of the filter are connected to the suction device 74 by piping or the like via the switching valve 75. The suction device 74 has a suction force capable of sucking in both gas and solids, and is configured, for example, using a cleaner or the like. When solids such as material powder and impurities are sucked in together with the gas by the suction device 74, the filter separates only the solids from the airflow and drops them by utilizing the difference in specific gravity. As a result, the solids are transported, and the gas is sucked into the suction device 74 from the exhaust ports 71a and 78a. Note that one suction device 74 may be switchably connected to the material recovery transport device 71 and the material supply transport device 78 via the switching valve 75, or one suction device 74 may be independently connected to each of the material recovery transport device 71 and the material supply transport device 78.

The suction nozzle 79 is configured to be able to suck up excess material powder on the modeling table 4. The suction nozzle 79 is stored in a storage section (not shown) outside the chamber 1, and when suction is to be performed, it is grasped by the mobile robot 8 and moved into the chamber 1.

For the purpose of cleaning the inside of the chamber 1, the suction nozzle 79 may be used to suck up excess material and cutting chips that have scattered in areas other than above the modeling table 4 in the chamber 1 (in other words, outside the modeling area R). If modeling is performed with excess material remaining in areas outside the modeling area R, this may cause operational abnormalities or failures during automatic operation of the additive manufacturing device 100. This can be avoided by using the suction nozzle 79 to suck and remove excess material from areas outside the modeling area R.

The suction nozzle 79 in this embodiment is connected to the suction port 71b of the material recovery transport device 71 by piping or the like via the switching valve 72. For example, the suction nozzle 79 can be attached to one end of a flexible hose, and the other end of the hose can be connected to the suction port 71b via the switching valve 72. The material powder sucked through the suction nozzle 79 is subjected to a process for removing impurities and a process for drying in the same manner as described above, and then supplied into the main duct 12.

The additive manufacturing apparatus 100 of this embodiment is equipped with a detection means (not shown) capable of detecting the ratio of the material powder in the object to be sucked by the suction nozzle 79. As the ratio of the material powder in the object to be sucked, for example, the volumetric flow rate ratio or mass flow rate ratio of the material powder in the object to be sucked, or the area ratio in a predetermined detection area can be used. In this embodiment, a flow sensor is installed as a detection means inside the suction nozzle 79 or the hose to which the suction nozzle 79 is attached. As an example, the flow sensor is configured to be able to detect the volumetric flow rate of the powder in the object to be sucked. Specifically, the flow sensor transmits microwaves at a predetermined position inside the suction nozzle 79 or the hose and receives the reflected waves. Since the frequency and amplitude of the reflected waves change depending on the amount of powder in the object to be sucked that passes through the predetermined position, the volumetric flow rate of the material powder in the object to be sucked can be detected based on the change, and the volumetric flow rate ratio of the material powder can be obtained. The detection result by the detection means is output to the control device 9. The detection means may be configured to directly detect the ratio of the material powder in the object to be sucked, or may be configured to indirectly detect the ratio of the material powder. When detecting indirectly, for example, the proportion of gas in the object to be sucked may be detected, and the proportion of material powder may be obtained from the detection result.

Figures 9A and 9B are diagrams showing the tip of the suction section 79a of the suction nozzle 79. Figure 9A is a front view, and Figure 9B is a right side view. The suction nozzle 79 of this embodiment has a suction section 79a on the tip side. Also, although not shown in Figures 9A and 9B, a gripping section that can be gripped by the mobile robot 8 is provided on the base end side of the suction nozzle 79. The suction section 79a has a cylindrical shape with the end face on the tip side cut by an inclined surface, and an opening 79b is provided on the inclined surface. Excess material is sucked through the opening 79b.

In this configuration, as shown in FIG. 10, when the suction nozzle 79 is brought close to the layer made of excess material (excess material layer 81a) and part of the opening 79b is embedded in the excess material layer 81a, the material powder is sucked through the opening 79b. At this time, gas is sucked through the part of the opening 79b that is not embedded in the excess material layer 81a. By sucking the material powder together with the gas, it is possible to avoid a situation in which the proportion of solids in the object being sucked is excessive, which would reduce the suction force, or cause clogging inside the suction nozzle 79 and hose.

The material recovery device 7 of this embodiment has a recovery mode and a suction mode as operation modes, and the operation modes are switched by the material supply/recovery control unit 98 of the control device 9 described later. In the recovery mode, the material recovery device 7 recovers the material powder in the material recovery bucket 70, removes impurities, and supplies the material powder to the material layer forming device 2. On the other hand, in the suction mode, the material recovery device 7 moves the suction nozzle 79 by the mobile robot 8, and sucks up excess material powder on the modeling table 4 with the suction nozzle 79. In this embodiment, the material supply/recovery control unit 98 switches the switching valve 72 to switch between a recovery mode in which the material recovery bucket 70 is the source of the material powder transported by the material recovery transport device 71, and a suction mode in which the source of the transport is the suction nozzle 79.

1.8. Mobile Robot 8
The mobile robot 8 is configured to be able to move the suction nozzle 79. The mobile robot 8 of this embodiment can grasp the suction nozzle 79 stored in a storage section outside the chamber 1, move into the chamber 1 through the work door, and place the suction nozzle 79 at any position within the chamber 1. The mobile robot 8 can also change the attitude (direction and angle) of the suction nozzle 79 with respect to the model W by performing an operation such as tilting the suction nozzle 79. The mobile robot 8 may be separate from the transport robot 6 as shown in FIG. 1, or may be mounted on the transport robot 6.

The mobile robot 8 is controlled by a mobile robot control unit 99 of the control device 9, which will be described later, to move the suction nozzle 79. This control is performed according to teaching data acquired in advance. The teaching data includes the movement path and posture of the suction nozzle 79 that correspond to the shape of the model W and the height of the modeling table 4.

As shown in FIG. 1, the mobile robot 8 of this embodiment includes a robot arm 8a and a robot hand 8b that is provided at the tip of the robot arm 8a and holds a suction nozzle 79, and is driven by a driving device (not shown). The mobile robot 8 also includes a torque sensor 8c that can detect the torque acting on the joint of the robot arm 8a. The torque detection result by the torque sensor 8c is output to the control device 9.

Imaging device 18
The imaging device 18 is configured to be able to acquire an image of an area (imaging area) that includes at least the base plate 83 and the model W. The imaging device 18 is, for example, a CCD camera or a CMOS camera. The acquired image is output to an image processing device 90c, which will be described later.

As shown in FIG. 1, the imaging device 18 is installed in the chamber 1. The installation position in the chamber 1 is not particularly limited as long as the imaging area can be imaged and the movement of the recoater head 22 or the irradiation of the laser light B during modeling is not hindered. For example, the imaging device 18 may be installed near the ceiling of the chamber 1 to image the imaging area from above, or may be installed near the side wall of the chamber 1 to image the imaging area from the side. The imaging device 18 may be installed movably in the chamber 1 to change the imaging area and imaging direction, or multiple imaging devices 18 may be installed to image multiple imaging areas and imaging directions. In addition, when the suction nozzle 79 is used to suction excess material in the area outside the modeling area R as described above, the area may be included in the imaging area.

The acquired image is used to determine whether or not the suction of the excess material by the suction nozzle 79 has been completed based on the presence or absence of excess material in the imaging area. For this purpose, the imaging device 18 acquires at least two types of images: an image of the imaging area in which the base plate 83 and the completed model W are fixed in the modeling area R by the chuck device 5 and no excess material is present (clean image), and an image of the imaging area when it is determined that the suction has been completed (determination image). By analyzing the difference between the clean image and the determination image by the image processing device 90c, it becomes possible to determine whether or not the suction of the excess material by the suction nozzle 79 has been completed. The clean image can be acquired by capturing an image in a state where the excess material in the chamber 1 has been removed after the modeling of the model W is completed, during test modeling, which is performed as a preliminary investigation for the manufacture of the model W.

Control device 9
As shown in Fig. 11, the control system of the additive manufacturing apparatus 100 includes a CAD (Computer Aided Design) device 90a, a CAM (Computer Aided Manufacturing) device 90b, an image processing device 90c, and a control device 9. These devices are configured by arbitrarily combining hardware such as a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an auxiliary storage device, and an input/output interface, and software. The following description will be limited to the control operations performed by the control system that are closely related to the present invention.

The CAD device 90a creates three-dimensional shape data (CAD data) that specifies the shape and dimensions of the three-dimensional object W to be modeled. The CAM device 90b creates a project file that specifies commands for the additive manufacturing device 100 based on the CAD data. The CAM device 90b sends the project file to the control device 9 via a communication line or a storage medium.

The image processing device 90c analyzes the clean image and the judgment image acquired by the imaging device 18. In one example, the image processing device 90c performs appropriate pre-processing on the image, and then performs binarization processing to distinguish between areas in the image where the material powder is present and other areas. The analysis data in which each area is labeled by the binarization processing is sent to the control device 9. The binarization processing is preferably performed on a pixel-by-pixel basis of the image data, or on a cell-by-cell basis consisting of multiple pixels.

The control device 9 controls the components of the additive manufacturing device 100, such as the material layer forming device 2, the irradiation device 3, the modeling table 4, the chuck device 5, the transport robot 6, the material recovery device 7, and the mobile robot 8, in accordance with the project file, and performs additive manufacturing. The control device 9 includes a numerical control unit 91 and control units 92, 93, 94, 95, 96, 97, 98, and 99 for the components of the additive manufacturing device 100.

The numerical control unit 91 outputs operation commands for the components of the additive manufacturing device 100 to the respective control units 92, 93, 94, 95, 96, 97, and 98 in accordance with the project file created by the CAM device 90b, and includes a storage unit 91a, a calculation unit 91b, and a memory 91c. The storage unit 91a stores the project file acquired from the CAM device 90b and teaching data for controlling the mobile robot 8. The calculation unit 91b executes calculation processing for numerically controlling the components of the additive manufacturing device 100 in accordance with the project file. The calculation unit 91b also outputs operation commands based on the teaching data to the mobile robot control unit 99.
The memory 91c temporarily stores numerical values and data during the calculation process performed by the calculation unit 91b.

The control units 92, 93, 94, 95, 96, 97, 98, and 99 of the components of the additive manufacturing device 100 control the operation of each component based on operation commands from the numerical control unit 91. Specifically, the work door control unit 92 controls the work door to open and close it at the appropriate time. The material layer formation control unit 93 controls the recoater head drive unit 23 to move the recoater head 22 back and forth in one horizontal axis direction. The irradiation control unit 94 controls the irradiation device 3 so that the laser light B is irradiated to a predetermined position within the irradiation area under predetermined conditions.

The table control unit 95 controls the table drive mechanism 41 to move the modeling table 4 vertically and position it at a predetermined position. The chuck control unit 96 controls the clamp unit 52 of the chuck device 5 to switch between fixing and releasing the base plate 83.

The transport robot control unit 97 controls the transport robot 6 to load the base plate 83 into the chamber 1 and remove the base plate 83 and the molded object W from the chamber 1, and also, if necessary, inverts the molded object W after removal from the chamber 1 and moves it to the secondary processing device.

The material supply/recovery control unit 98 controls the material recovery device 7 and the material supply unit 10. It also switches the operating mode of the material recovery device 7.

The mobile robot control unit 99 controls the mobile robot 8 to grip the suction nozzle 79 and move it into the chamber 1. Furthermore, the mobile robot control unit 99 controls the mobile robot 8 to move the suction nozzle 79 within the chamber 1 while sucking up the excess material. Note that when the mobile robot 8 is mounted on the transport robot 6, the transport robot control unit 97 may be given the functions of the mobile robot control unit 99 described above.

In addition to the above-mentioned configuration, the additive manufacturing apparatus 100 may be provided with a machining device (not shown) in the chamber 1 for performing machining such as cutting on the solidified layer 82 and the model W as necessary. The machining device is configured, for example, by attaching a tool (e.g., an end mill) for performing machining such as cutting to a machining head, and the machining head is moved appropriately in the horizontal and vertical directions to perform machining on the solidified layer 82 or the model W. The tool may also be configured to be rotatable by being attached to a spindle of the machining head.

2. Manufacturing method of the three-dimensional object W Next, a manufacturing method of the three-dimensional object W using the additive manufacturing apparatus 100 according to this embodiment will be described with reference to Fig. 12. The manufacturing method according to this embodiment includes a placing step S1-1, a material supplying step S1-2, a solidified layer forming step S1-3, a material recovering step S1-4, a suction step S1-5, and a removal step S1-6.

2.1. Placement step S1-1
In the placing step S1-1, the base plate 83 is placed in the modeling region R on the modeling table 4. Specifically, first, the work door control unit 92 controls the work door to open it. In addition, the transport robot control unit 97 controls the transport robot 6 to carry the base plate set from a stocker outside the chamber 1 into the chamber 1. The transport robot 6 carries the base plate set into the chamber 1 through the opened work door, and inserts the lower end of the shaft 87 into the insertion hole 52e of the clamp unit 52. In this state, the chuck control unit 96 controls the clamp unit 52 of the chuck device 5 to engage the ball 52d with the locking portion 87b of the shaft 87. As a result, as shown in FIG. 14, the base plate 83 is placed in the modeling region R in a state in which it is detachably fixed to the chuck device 5. In addition, the side of the chuck device 5 is covered by the chuck cover 53 consisting of the outer cover 54 and the inner cover 55.

After the base plate 83 is placed, the transport robot control unit 97 controls the transport robot 6 to retreat outside the chamber 1, and the work door control unit 92 closes the work door. After that, the inert gas is supplied from the inert gas supply device to fill the chamber 1. This makes it possible to start modeling.

2.2. Material supply process S1-2
In the material supplying step S1-2, the material powder is supplied to and stored in the material storage unit 22a of the material layer forming device 2. Specifically, the material layer formation control unit 93 controls the recoater head driving device 23. Then, the recoater head 22 is moved to a position immediately below the intermediate duct 13. In this state, the material supply/recovery control unit 98 controls the material supply unit 10 to open the shutter 14 and release the material powder into the material container. When a sufficient amount of material powder has been supplied, the material supply/recovery control unit 98 closes the shutter 14 to stop the supply. The recoater head driving device 23 is controlled to move the recoater head 22 to the modeling region R. In the material supplying step S1-2, the material powder is supplied to the material storage unit 22a from the start to the completion of modeling. This is done multiple times in a timely manner to replenish.

2.3. Solidified layer forming step S1-3
Next, a solidified layer forming step S1-3 is performed. The solidified layer forming step S1-3 includes a material layer forming step S1-3-1 in which material powder is supplied onto the base plate 83 to form the material layer 81. Then, a solidification step S1-3-2 in which a solidified layer 82 is formed by irradiating a predetermined irradiation region of the material layer 81 with the laser beam B is repeated, whereby the solidified layers 82 are laminated.

Specifically, first, the table control unit 95 controls the table driving mechanism 41 to position the modeling table 4 at a predetermined height. In this state, the material layer formation control unit 93 controls the recoater head driving device 23 to move the recoater head 22 from the left side to the right side in FIG. 14. This forms the first material layer 81 on the base plate 83. Next, the irradiation control unit 94 controls the irradiation device 3 to irradiate a predetermined irradiation area of the first material layer 81 with the laser light B or the electron beam. This solidifies the first material layer 81, as shown in FIG. 15, to obtain the first solidified layer 82.

Then, the second material layer forming step S1-3-1 is performed. After forming the first solidified layer 82, the table control unit 95 controls the table driving mechanism 41 to lower the height of the modeling table 4 by one material layer 81. In this state, the material layer forming control unit 93 controls the recoater head driving device 23 to move the recoater head 22 from the right side to the left side of the modeling region R in FIG. 15. As a result, the second material layer 81 is formed so as to cover the first solidified layer 82. Then, the second solidification step S1-3-2 is performed. In the same manner as described above, the second material layer 81 is solidified by irradiating a predetermined irradiation area of the second material layer 81 with the laser light B, thereby obtaining the second solidified layer 82.

The material layer forming step S1-3-1 and the solidifying step S1-3-2 are repeated until the desired three-dimensional object W is obtained, and multiple solidified layers 82 are stacked. Adjacent solidified layers 82 are strongly bonded to each other. In addition, cutting or other processes are performed by a machining device as necessary during or after the modeling.

2.4. Material recovery process S1-4
In parallel with the solidified layer forming step S1-3, a material recovery step S1-4 is performed. In the material recovery step S1-4, the material recovery device 7 operates in a recovery mode. Specifically, the material supply/recovery control unit 98 switches the switching valve 72 so that the material recovery bucket 70 is the source of the material powder transported by the material recovery transport device 71. In addition, the material recovery transport device 71, the impurity removal device 73, the suction device 74, the material supply bucket 76, the material drying device 77, and the material supply transport device 78 are operated to perform an impurity removal process and a drying process on the material powder containing impurities in the material recovery bucket 70, and then supply it into the main duct 12.

2.5. Suction step S1-5
After the modeling is completed, a suction process S1-5 is performed. In the suction process S1-5, the surplus material on the modeling table 4 is sucked by the suction nozzle 79. Specifically, first, the work door control unit 92 Next, the mobile robot control unit 99 controls the mobile robot 8 to grip the suction nozzle 79 and move it from the working door into the chamber 1. Also, in the suction step S1-5, The material recovery device 7 operates in the suction mode. The material supply/recovery control unit 98 switches the switching valve 72 so that the source of the material powder transported by the material recovery transport device 71 is the suction nozzle 79.

As shown in Figure 16, between the start and end of modeling, the modeling table 4 descends by a height Hw, which is equivalent to the total thickness of the material layer 81 formed on the base plate 83. In the following explanation, the vertical position (height) of the modeling table 4 is shown in a one-axis coordinate system along the vertical direction, with the position of the top surface of the modeling table at the start of modeling as the origin, as shown in Figures 14 and 16. The position of the modeling table 4 at the start of modeling in Figure 14 is H = 0, and the position of the modeling table 4 at the end of modeling in Figure 16 is H = -Hw.

As shown in FIG. 16, when the position of the modeling table 4 is at H=-Hw, the mobile robot control unit 99 controls the mobile robot 8 to move the suction nozzle 79 and starts suctioning the excess material with the suction nozzle 79. When suctioning the excess material, the control device 9 alternately repeats the following steps: control the table drive mechanism 41 with the table control unit 95 to raise the modeling table 4 by a predetermined lift amount Δh (lifting step S1-5-1), and control the mobile robot 8 with the mobile robot control unit 99 in accordance with the teaching data to move the suction nozzle 79 while sucking up the excess material powder (excess material suction step S1-5-2).

An example of such a repetitive operation will be described. Prior to the manufacture of the model W, the movement path and posture of the suction nozzle 79 corresponding to the model W are acquired as teaching data for each lift amount Δh of the model table 4. For example, when Δh=50 mm, the movement path and posture when the model table 4 is at position H=-Hw (operation pattern P1), the movement path and posture when the model table 4 is at position H=-Hw+50 mm (operation pattern P2), the movement path and posture when the model table 4 is at position H=-Hw+100 mm (operation pattern P3), the movement path and posture when the model table 4 is at position H=-Hw+150 mm (operation pattern P4)... The movement path and posture of the suction nozzle 79 corresponding to each position of the model table 4 from position H=-Hw to position H=0 are acquired as operation patterns P1, P2, P3, P4, ... Pn.

The mobile robot control unit 99 first performs the first surplus material suction process S1-5-2 with the modeling table 4 at position H = -Hw. Specifically, it controls the mobile robot 8 to move the suction nozzle 79 according to the motion pattern P1, and suctions the surplus material from the upper surface side of the surplus material layer 81a. When the movement according to the motion pattern P1 is completed, the mobile robot control unit 99 outputs a completion signal to the numerical control unit 91.

When the numerical control unit 91 receives the completion signal, it outputs an operation command to the table control unit 95 to raise the modeling table 4. In the first raising step S1-5-1, the table control unit 95 controls the table drive mechanism 41 to raise the modeling table 4 by an amount of lift Δh to position H = -Hw + 50 mm. This raises the upper surface of the surplus material layer 81a. In this state, the second surplus material suction step S1-5-2 is performed. The mobile robot control unit 99 controls the mobile robot 8 to move the suction nozzle 79 according to the operation pattern P2, and sucks up the surplus material from the upper surface side of the surplus material layer 81a.

Until the modeling table 4 reaches position H=0, the control device 9 alternately repeats the raising process S1-5-1 and the excess material suction process S1-5-2.

The teaching data is acquired by recording the position and orientation of the suction nozzle 79 when the mobile robot 8 is manually operated to move the suction nozzle 79 while sucking up the excess material, and indicates the optimal movement path and orientation of the suction nozzle 79 corresponding to the shape of the model W and the height of the modeling table 4. By sucking up the excess material while moving the suction nozzle 79 in accordance with the teaching data, the excess material can be removed more reliably and efficiently.

The amount of lift Δh of the modeling table 4 in one lift operation in the suction step S1-5 is preferably 20 to 80 mm, more preferably 35 to 65 mm, for example 50 mm. If the amount of lift in one lift operation is too small, the lift operations may be repeated too frequently, reducing the efficiency of the suction step S1-5. On the other hand, if the amount of lift is too large, the height of the upper surface of the excess material layer 81a may exceed the upper end of the powder holding wall 42, making it impossible to hold it on the modeling table 4.

In this embodiment, the control device 9 judges the presence or absence of excess material powder using the image acquired by the imaging device 18. Specifically, as described above, a clean image is acquired in advance in the test modeling, and in the suction process S1-5, when suction by the suction nozzle 79 in each operation pattern P1, P2, P3, P4, ... Pn is completed and the modeling table 4 is raised to position H = 0, a judgment image is acquired by the imaging device 18. The image processing device 90c analyzes the clean image and the judgment image. The numerical control unit 91 of the control device 9 compares these analysis data to judge the presence or absence of excess material in the imaged area.

As an example, the number of pixels or cells labeled by the binarization process as locations where material powder is present is counted in the analysis data of the clean image and the judgment image, respectively. Then, if the difference (Nj-Nc) between the count number Nc in the analysis data of the clean image and the count number Nj in the analysis data of the judgment image is equal to or less than a predetermined value, it is determined that all of the excess material has been sucked up. On the other hand, if the difference (Nj-Nc) is greater than the predetermined value, it is determined that excess material remains in the image capture area, and suction is performed again by the suction nozzle 79. When suctioning again, the suction nozzle 79 may be moved according to the final operation pattern Pn associated with the rise of the modeling table 4, or may be moved according to the operation pattern for suctioning again acquired as teaching data.

In this way, by determining the presence or absence of excess material based on the image captured by the imaging device 18, it is possible to reliably remove excess material in the imaging area including the base plate 83 and the model W. In particular, even if the size of the base plate 83 and the model W is relatively large, or if the suction by the suction nozzle 79 is wide due to suctioning excess material in an area outside the modeling area R, it is possible to determine the presence or absence of excess material and reliably remove it.

Furthermore, the control device 9 of this embodiment determines whether or not there is excess material powder based on the detection result of the detection means. Specifically, when the ratio of material powder in the object being sucked by the suction nozzle 79 becomes approximately 0, it determines that all of the excess material in the imaging area has been sucked.

When making a judgment based on the image acquired by the imaging device 18, it may be difficult to judge the presence or absence of excess material in fine grooves and other small parts of the molded object W, and the accuracy of the judgment may decrease depending on the type of material powder and the lighting conditions inside the chamber 1. In such cases, the judgment can be made by using the detection results of the detection means.

While it is possible to determine the presence or absence of surplus material based on the image captured by the imaging device 18 and the detection result of the detection means, it is preferable to use both methods together. By using the former, which allows for wide-area determination, and the latter, which allows for determination in fine details such as grooves and is less susceptible to the effects of the type of material powder and lighting, in combination, it is possible to perform highly accurate determinations and more reliably remove surplus material.

Note that while the suction nozzle 79 is moving, the suction operation may be stopped or the movement path may be corrected based on the detection result of the torque sensor 8c. When the suction nozzle 79 comes into contact with the model W or the base plate 83, the torque acting on the joint of the robot arm 8a increases. When the detected torque value is large, for example, the suction operation may be temporarily stopped or the movement path of the suction nozzle 79 may be corrected so that it moves away from the model W or the base plate 83, thereby making it possible to avoid damage to the model W.

After suction is completed, the mobile robot control unit 99 controls the mobile robot 8 to move the suction nozzle 79 from the work door to outside the chamber 1 and store it in the storage unit. This completes the suction process S1-5.

2.6. Removal process S1-6
After the suction step S1-5 is completed, a removal step S1-6 is performed, in which the base plate 83 and the object W formed on the base plate 83 are removed from the chamber 1. Specifically, first, the chuck control unit 96 controls the clamp unit 52 of the chuck device 5 to disengage the ball 52d from the locking portion 87b, thereby releasing the fixation of the base plate 83 by the chuck device 5. Next, the transfer robot control unit 97 controls the transfer robot 6 to remove the base plate 83 and the object W together with the mounting plate 84, the pallet 85, the shaft 87, and the outer cover 54 from the chamber 1.

After removing the object W from the chamber 1, the transport robot control unit 97 may control the transport robot 6 to invert the object W upside down to drop the excess material, or place the inverted object W on a finishing device to finish and remove the excess material. In addition, when performing secondary processing, the transport robot control unit 97 controls the transport robot 6 to move the object W to the secondary processing device, and then the secondary processing step S1-7 is performed. In this case, by introducing a fixing device having a configuration similar to that of the chuck device 5 into the secondary processing device, the transport robot 6 can be controlled to fix and position the base plate 83 and the object W on the fixing device via the mounting plate 84 and pallet 85, similar to the fixing to the chuck device 5 in the placement step S1-1. This enables automation of the placement of the object W on the secondary processing device, and ensures the same placement accuracy as when it is placed on the modeling region R, enabling high-precision secondary processing.

After the removal step S1-6 is completed, the above steps are repeated to sequentially manufacture the three-dimensional object W. In this configuration, the suction nozzle 79 automatically removes excess material after modeling is complete, making it possible to remove the object W from the chamber 1 unmanned.

3. Method for Acquiring Teaching Data Next, a teaching method for acquiring teaching data will be described. The teaching method of this embodiment includes a placement process S2-1, a material supply process S2-2, a modeling process S2-3, a recording process S2-4, and a lifting process S2-5. Acquisition of teaching data by the teaching method is performed prior to the manufacture of the model W (for example, in test modeling). The following description will be given taking as an example a case where teaching data is acquired using the additive manufacturing device 100, but it is also possible to use another additive manufacturing device.

In the placing step S2-1, the base plate 83 is detachably fixed by the chuck device 5 arranged on the modeling table 4, so that the base plate 83 is placed in the modeling region R on the modeling table 4, which is the region where the model W is to be formed. The placing step S2-1 is performed in the same manner as the placing step S1-1 in the manufacturing method of the model W.

In the material supplying step S2-2, the material powder is supplied to and stored in the material storage section 22a of the material layer forming device 2. The material supplying step S2-2 is performed in the same manner as the material supplying step S1-2 in the method for manufacturing the molded object W.

In the modeling process S2-3, a material layer forming process S2-3-1 in which material powder is supplied onto a base plate 83 to form a material layer 81, and a solidification process S2-3-2 in which a predetermined irradiation area of the material layer 81 is irradiated with a laser beam B or an electron beam to form a solidified layer 82 are repeated to stack the solidified layers 82 to form a three-dimensional object. The material layer forming process S2-3-1 and the solidification process S2-3-2 are performed in the same manner as the material layer forming process S1-3-1 and the solidification process S1-3-2 in the solidified layer forming process S1-3 in the manufacturing method of the model W, respectively.

After the modeling is completed in the modeling process S2-3, the recording process S2-4 and the lifting process S2-5 are carried out. In the recording process S2-4, the worker manually operates the mobile robot 8 to move the suction nozzle 79 while sucking up the excess material powder on the modeling table 4, and the position coordinates and attitude of the suction nozzle 79 at this time are transferred to the control device 9 and recorded.

Specifically, after the modeling is completed, when the modeling table 4 is at the position H = -Hw, the mobile robot 8 is manually operated to move the suction nozzle 79 to suck the excess material from the upper surface side of the excess material layer 81a. At this time, the suction nozzle 79 is moved until a predetermined depth Δd of excess material is removed from the upper surface side of the excess material layer 81a while adjusting the position and posture of the suction nozzle 79 so that the suction nozzle 79 does not come into contact with the modeled object W or the base plate 83 and can efficiently suck up the excess material present in the depressions of the modeled object W. The depth Δd is set to be equal to the lift amount Δh of the modeling table 4. The position coordinates and posture of the suction nozzle 79 during such movement are recorded at multiple points and are set as the operation pattern P1. Note that the movement path of the suction nozzle 79 between the points may be, for example, a straight line connecting two points (linear interpolation), or may be created based on the shape data of the desired three-dimensional model W.

After removing the excess material to a depth Δd in the first recording step S2-4, the modeling table 4 is raised by a predetermined lift amount Δh in the raising step S2-5. This raises the upper surface of the excess material layer 81a. In this state, the second recording step S2-4 is executed. As in the first step, the mobile robot 8 is manually operated to move the suction nozzle 79 to suck up the excess material to a depth Δd from the upper surface side, and the position coordinates and posture of the suction nozzle 79 during movement are recorded at multiple points, which is defined as the operation pattern P2.

By repeating the recording step S2-4 and the raising step S2-5 until the modeling table 4 reaches position H=0 and the suction of excess material is completed, teaching data including the movement path and posture of the suction nozzle 79 corresponding to the height of the model W and the modeling table 4 is acquired as operation patterns P1, P2, P3, P4, ... Pn. This makes it possible to acquire teaching data including the optimal movement path and posture of the suction nozzle 79 corresponding to the shape of the model W and the height of the modeling table 4.

In this way, the movement of the suction nozzle 79 based on the operation pattern obtained by manual operation of the mobile robot 8 is particularly significant in suctioning and removing excess material, etc., when the modeling table 4 is at the top position (position H = 0). By moving the suction nozzle 79 in a suitable movement path and posture when the modeling table 4 has reached the top position, it is possible to avoid a situation in which excess material, etc. remains on the modeling table 4 and adversely affects the next modeling, and it is also possible to efficiently remove excess material, etc. that has scattered outside the modeling area R, making it possible to automate cleaning work inside the chamber 1 for maintenance purposes.

The number of points included in one operation pattern can be set appropriately depending on the size and shape of the object W and the modeling table 4, but is, for example, 5 to 40, and preferably 10 to 20. If the number of points is too small, the efficiency of removing excess material may decrease or contact with the object W or base plate 83 may increase when the suction nozzle 79 is moved based on the teaching data. If the number of points is too large, control of the mobile robot 8 may become complicated.

In addition, in the recording step S2-4, the detection results of the torque sensor 8c may be recorded in addition to the position coordinates and attitude of the suction nozzle 79. By removing data on points with large torque values from the recorded position coordinates and attitude, it is possible to create an operation pattern with less contact with the model W and base plate 83.

4. Other Embodiments The present invention can also be implemented in the following aspects.

In the above embodiment, a clean image is obtained by forming an object W in test forming, and an object W is formed in forming step S2-3 of the teaching method, but the present invention is not limited to this configuration. For example, clean images and teaching data may be obtained for a number of objects of different sizes, and when manufacturing the object W, the clean image and teaching data of the object that is closest in size among the multiple objects may be used. In such a configuration, it is sufficient to obtain clean images and teaching data for several objects of representative sizes, and there is no need to obtain clean images and teaching data for each object W.

Although various embodiments of the present invention have been described above, these are presented as examples and are not intended to limit the scope of the invention. The novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. The embodiments and their modifications are included within the scope and gist of the invention, and are included in the scope of the invention and its equivalents as set forth in the claims.

1: chamber, 1a: window, 2: material layer forming device, 3: irradiation device, 4: modeling table, 5: chuck device, 6: transport robot, 7: material recovery device, 8: mobile robot, 8a: robot arm, 8b: robot hand, 8c: torque sensor, 9: control device, 10: material supply unit, 11: material tank, 12: main duct, 13: intermediate duct, 13a: intermediate duct outlet, 14: shutter, 17: contamination prevention device, 17a: housing, 17b: diffusion member, 18: imaging device, 21: base, 22: recoater head, 22a: material storage section, 22b : material supply port, 22c: material discharge port, 22fb: blade, 22rb: blade, 23: recoater head drive device, 41: table drive mechanism, 42: powder holding wall, 51: chuck base, 52: clamp unit, 52a: first convex portion, 52b: second convex portion, 52c: abutment recess, 52d: ball, 52e: insertion hole, 53: chuck cover, 54: outer cover, 54a: outer covering portion, 54b: upper surface portion, 55: inner cover, 55a: inner covering portion, 55b: flange portion, 70: material recovery bucket, 70a: powder discharge portion, 70b: powder discharge portion, 70c: shell a feeder guide, 70d: chute guide, 70e: chute, 71: material recovery transport device, 71a: exhaust port, 71b: suction port, 72: switching valve, 73: impurity removal device, 74: suction device, 75: switching valve, 76: material supply bucket, 77: material drying device, 78: material supply transport device, 78a: exhaust port, 79: suction nozzle, 79a: suction section, 79b: opening, 81: material layer, 81a: surplus material layer, 82: solidified layer, 83: base plate, 84: mounting plate, 85: pallet, 86: positioning plate, 86a: first opening, 86b: second opening Mouth, 86c: Support foot, 86d: Mounting shaft, 87: Shaft, 87a: Chucking plug, 87b: Locking part, 87c: Recess, 90: Image processing device, 90a: CAD device, 90b: CAM device, 91: Numerical control unit, 91a: Storage unit, 91b: Calculation unit, 91c: Memory, 92: Work door control unit, 93: Material layer formation control unit, 94: Irradiation control unit, 95: Table control unit, 96: Chuck control unit, 97: Transport robot control unit, 98: Material supply/recovery control unit, 99: Mobile robot control unit, 100: Layered modeling device, B: Laser light, R: Modeling area, W: Three-dimensional model

Claims (12)

An additive manufacturing apparatus including a modeling table, a chamber, a material layer forming device, a chuck device, a material recovery device, a transport robot, a moving robot, and a control device,
The modeling table is configured to be movable up and down by a table driving mechanism,
the chamber covers a printing area, which is an area on the printing table where a model is formed;
the material layer forming device supplies material powder onto a base plate placed in the modeling region to form a material layer;
the chuck device is disposed on the modeling table and configured to be able to detachably and fix the base plate within the modeling region;
the material recovery device includes a suction nozzle capable of sucking up excess material powder on the modeling table,
the transfer robot is configured to be capable of removing the base plate and the object formed on the base plate from the chamber,
The mobile robot is configured to be able to move the suction nozzle,
the control device alternately repeats controlling the table drive mechanism to raise the modeling table by a predetermined lift amount, and controlling the mobile robot in accordance with teaching data to move the suction nozzle while suctioning the excess material powder;
An additive manufacturing apparatus, wherein the teaching data includes a movement path and a posture of the suction nozzle corresponding to a shape of the object and a height of the modeling table. The additive manufacturing apparatus according to claim 1 ,
an imaging device configured to acquire an image of an area including at least the base plate and the object;
The control device determines whether or not there is excess material powder using the image acquired by the imaging device. The additive manufacturing apparatus according to claim 1 or 2,
a detection means for detecting a ratio of the material powder in the object to be sucked by the suction nozzle;
The control device determines whether or not there is surplus material powder based on the ratio of the material powder. The additive manufacturing apparatus according to claim 3,
The additive manufacturing apparatus, wherein the detection means is a flow rate sensor. The additive manufacturing apparatus according to claim 1 or 2,
a powder retaining wall surrounding the modeling table and configured to retain the material powder on the modeling table;
a material recovery bucket configured to receive excess material powder discharged outside the powder retaining wall;
The material recovery device has a recovery mode and a suction mode as operation modes,
The control device is configured to switch the operation mode,
An additive manufacturing device configured such that, in the recovery mode, the material recovery device recovers the material powder in the material recovery bucket and removes impurities before supplying the material powder to the material layer forming device, and in the suction mode, the suction nozzle is moved by the mobile robot to suck up excess material powder on the modeling table through the suction nozzle and removes impurities from the material powder. The additive manufacturing apparatus according to claim 1 or 2,
A side surface of the chuck device is covered by a chuck cover,
The chuck cover includes an outer cover and an inner cover,
The outer cover covers at least a portion of a side surface of the inner cover,
An additive manufacturing apparatus, wherein the inner cover covers the side surface of the chuck device. The additive manufacturing apparatus according to claim 1 or 2,
The chuck device fixes the base plate via a mounting plate, The additive manufacturing apparatus according to claim 1 or 2,
The suction nozzle has a suction portion at a tip end thereof,
The suction portion has a cylindrical shape with a tip end surface cut by an inclined surface,
An additive manufacturing apparatus, wherein the inclined surface is provided with an opening. The additive manufacturing apparatus according to claim 1 or 2,
The transfer robot is configured to be capable of carrying the base plate into the chamber. The additive manufacturing apparatus according to claim 1 or 2,
The transport robot is configured to invert the object after removing it from the chamber, an additive manufacturing apparatus. A method for manufacturing a three-dimensional object, comprising the steps of:
The method includes a placing step, a solidified layer forming step, a suction step, and a removal step,
In the placing step, the base plate is detachably fixed by a chuck device arranged on the modeling table, thereby placing the base plate in a modeling area, which is an area on the modeling table where a model is formed;
In the solidified layer forming step, a material layer forming step of supplying a material powder onto the base plate to form a material layer and a solidification step of irradiating a predetermined irradiation area of the material layer with a laser beam or an electron beam to form a solidified layer are repeated to stack the solidified layers,
In the suction step, the following are alternately repeated: raising the modeling table by a predetermined lift amount using a table driving mechanism; and suctioning the excess material powder while moving a suction nozzle using a mobile robot according to teaching data.
In the removing step, the base plate and the object formed on the base plate are removed from a chamber covering the modeling region by a transfer robot.
The teaching data includes a movement path and a posture of the suction nozzle corresponding to a shape of the object and a height of the modeling table. A teaching method for acquiring teaching data used when suctioning excess material powder generated in additive manufacturing of a three-dimensional object with a suction nozzle, comprising:
The method includes a placing step, a shaping step, a recording step, and a lifting step,
In the placing step, the base plate is detachably fixed by a chuck device arranged on the modeling table, thereby placing the base plate in a modeling area, which is an area on the modeling table where a model is formed;
In the modeling step, a material layer forming step of supplying a material powder onto the base plate to form a material layer and a solidifying step of irradiating a predetermined irradiation area of the material layer with a laser beam or an electron beam to form a solidified layer are repeated to stack the solidified layers to form a three-dimensional object.
In the recording step, the mobile robot is manually operated to move the suction nozzle while suctioning the excess material powder on the modeling table, and a position coordinate and a posture of the suction nozzle are recorded;
In the raising step, the modeling table is raised by a predetermined amount of elevation,
the teaching method further comprising: acquiring the teaching data, the teaching data including a moving path and a posture of the suction nozzle, corresponding to a shape of the object and a height of the modeling table, by repeating the recording step and the raising step.