JP2023054988A - Optical molding apparatus - Google Patents

Abstract

To provide an optical molding apparatus that can appropriately secure a supply of a molding material even when a molded object is large in size or has a large surface area.SOLUTION: An optical molding apparatus for obtaining a three-dimensional molded object includes: discharge means capable of discharging slurry onto a molding table; sweeping means that sweeps the slurry discharged onto the molding table to form a slurry film of a predetermined thickness; exposure means for exposing the slurry film according to an exposure pattern created in advance based on three-dimensional shape data; monitoring means for monitoring the amount of the slurry remaining in the discharging means during fabrication of the three-dimensional molded object; replenishment means for supplying additional slurry to the discharge means; and control means for causing the replenishment means to replenish the additional slurry to the discharge means at a predetermined timing when the remaining amount is less than a specified value.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a stereolithography apparatus, and more particularly to its material supply.

The three-dimensional modeling method is a processing method that has a great advantage in that it can directly shape and process complicated three-dimensional shapes, and has a great degree of freedom compared to the method of obtaining a three-dimensional three-dimensional processed product by conventional cutting methods. Its superiority has attracted a great deal of attention in recent years.

As a prior example of three-dimensional stereolithography, which is one of the three-dimensional fabrication methods, a method called a free liquid surface method is widely known, and is realized by a scanning exposure system of a laser beam and a galvanomirror. In addition, from the bottom side of the container containing the photocurable material, through the glass, one layer is modeled by collective exposure with DMD, then the modeled object is lifted by the required thickness, and the material is filled under the modeled object. Also known is a back surface exposure method called a regulated liquid surface method, in which modeling is performed by repeating exposure and lifting in this manner (see, for example, Patent Document 1).

However, in recent years, as a three-dimensional stereolithography method, a method of applying a photocurable resin on a plane and exposing it by laser scanning has become mainstream. For example, a paste-like material called slurry, which is a photocurable monomer resin (liquid) kneaded with ceramic powder, is applied thinly on the modeling table, and the required area is exposed by laser scanning from above to expose the resin. A method of obtaining a three-dimensional structure by repeating curing is already known (see Patent Document 2, for example).

JP 2017-124631 A Japanese Patent No. 6438919

As the superiority of the three-dimensional stereolithography method is widely recognized, there is an increasing need for a larger size and larger area of the modeled object. Alternatively, there is a tendency to increase the number of even small molded objects. As the size of the modeled object increases, or the number of objects to be modeled at once increases, the time required for the modeling process increases. measures for this are required.

Another matter that becomes apparent due to the increase in size, area, or quantity is the problem of supply of modeling material (slurry). In other words, there is a marked tendency to consume a large amount of expensive slurry at once during modeling. From the viewpoint of using the slurry efficiently and improving the throughput of the apparatus, it is required to discharge the slurry quickly and accurately, and to quickly supply additional slurry to the parts that discharge the slurry (discharge pump, discharge mechanism). be done.

Moreover, from the viewpoint of improving throughput, it is also necessary to have a mechanism that can reliably discharge a constant amount of slurry per unit time. In other words, in a stereolithography apparatus that performs a three-dimensional stereolithography method, slurry is normally discharged in a line while the slurry discharge pump is moving. On the other hand, there is a limit to increasing the size of the slurry discharge pump due to issues such as load capacity and movement accuracy. For example, since the weight of slurry using alumina is about 3 g per 1 cc, if the capacity of the slurry container in the slurry discharge pump is 2 liters, the maximum weight of the slurry in the container is 6 kg. Including the discharge mechanism and the structure that supports the entire slurry discharge pump, the slurry discharge pump as a whole becomes a moving body weighing well over 10 kg.

Therefore, when forming a large-sized object or a large-sized object, it is essential to appropriately supply additional slurry so that the slurry container of the moving slurry discharge pump does not become empty during the forming process. Neither Patent Literature 1 nor Patent Literature 2 has any particular disclosure regarding the supply of modeling material when modeling a large-sized or large-area modeled object.

For example, if the floor area of the model is 30 cm×30 cm, the 2 liters of slurry described above will be used up in a model with a height of 2.2 cm. With a floor area of 60 cm x 60 cm, only a model with a height of 5.5 mm can be produced.

In order to increase the throughput, it is preferable that the amount of slurry discharged per unit time is as large as possible. In particular, it is desirable to increase the moving speed as much as possible for a line that requires a smaller discharge amount. From this point of view as well, there is a limit to the weight of the slurry discharge pump.

In addition, since the slurry for modeling generally has a high viscosity, regardless of whether the material of the inner wall of the slurry container is metal or resin, once the slurry adheres to the inner wall, it hardly flows down and remains as it is. accumulate. Its thickness is usually several millimeters, and reaches nearly 10 mm depending on the conditions. Moreover, it usually does not fall off due to gravity even after several weeks. Therefore, although it depends on the size of the container, in some cases, a very large amount of slurry cannot be used (not used). For example, in the above-mentioned 2-liter container, 30% of the slurry remained against the force of gravity one week after the supply.

Therefore, from the viewpoint of improving productivity, it is also required to effectively use the slurry remaining on the inner wall surface of the slurry container.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a stereolithographic apparatus capable of appropriately ensuring the supply of molding materials even when the object to be molded is large in size and has a large area. do.

In order to solve the above-mentioned problems, the invention of claim 1 is a stereolithographic apparatus for obtaining a three-dimensional modeled object, comprising: a modeling table; a discharging means capable of discharging slurry onto the modeling table; sweeping means for sweeping the slurry discharged onto the table to form a slurry film of a predetermined thickness; exposure means for exposing the slurry film according to an exposure pattern prepared in advance based on three-dimensional shape data; monitoring means for monitoring the remaining amount of the slurry in the discharging means during the production of the three-dimensional model; supplying means for supplying additional slurry to the discharging means; and based on the monitoring results of the monitoring means, and control means for causing the replenishing means to replenish the additional slurry to the discharging means at a predetermined timing when the remaining amount is less than a specified value.

The invention according to claim 2 is the optical molding apparatus according to claim 1, wherein the replenishing means comprises a pipe that is inclined from a horizontal plane, and is housed in the pipe without contacting the pipe. a screw; a rotating means for rotating the screw within the pipe; a slurry container connected to an intermediate position of the pipe to store the additional slurry; and a supply part that is a slurry supply port, and the screw is rotated by the rotating means, so that the screw conveys the additional slurry stored in the slurry container within the pipe. and supplying to the discharge means through the supply portion.

The invention of claim 3 is the stereolithography apparatus according to claim 2, wherein the reservoir of the slurry container includes an inclined surface at an angle of 30 degrees or more and 70 degrees or less from the horizontal plane.

The invention of claim 4 is the stereolithography apparatus according to claim 2 or 3, wherein the particles adhere to the inner surface of the slurry container by moving along the inner surface of the slurry container within the slurry container. and a slurry container scraper for scraping off the additional slurry.

The invention of claim 5 is the stereolithography apparatus according to any one of claims 2 to 4, wherein the slurry container is placed at a predetermined position on the upper end of the slurry container with the opening directed downward or obliquely downward. a replenishment container that can be placed in the slurry, the replenishment container holds new slurry, and is placed at the predetermined position with the opening facing downward or obliquely downward, The new slurry is supplied to the slurry container as the additional slurry.

The invention according to claim 6 is the stereolithography apparatus according to claim 5, wherein the replenishment container moves along the inner surface of the replenishment container in the state where the replenishment container is placed at the predetermined position. a replenishment container scraper for scraping off the additional slurry adhering to the inner surface of the replenishment container.

The invention of claim 7 is the stereolithography apparatus according to claim 5 or 6, wherein the replenishment container is rotatably fixed to the slurry container, and the opening is directed upward or obliquely upward. a hinge for rotating the replenishment container from the open position to the position in which the opening faces downward or obliquely downward.

The invention of claim 8 is the stereolithography apparatus according to any one of claims 2 to 7, further comprising a drain provided in the pipe, wherein the supply path from the slurry container to the pipe The slurry remaining in the pipe can be discharged by releasing the drain with the lid closed and rotating the screw in a direction opposite to when the slurry is supplied.

The invention of claim 9 is the optical forming apparatus according to any one of claims 1 to 8, wherein the discharge means comprises a funnel-shaped discharge part tapered at a lower end and a Continuously comprising: a cylindrical storage part in which the slurry is stored; a discharge screw inserted from the storage part to the discharge part; and a drive motor for rotating the discharge screw, The slurry is discharged from the discharge section by rotating the screw for the nozzle by the drive motor.

According to the inventions of claims 1 to 9, even when a large-sized or large-area modeled object is modeled, the supply of the modeling material is preferably ensured.

1 is a perspective view showing a schematic configuration of an optical shaping apparatus 1; FIG. FIG. 2 is a functional block diagram of main parts of the stereolithography apparatus 1; FIG. 2 is a side view showing the arrangement relationship of main components in the stereolithography apparatus 1; 4 is a flowchart showing a series of operations of the stereolithography apparatus 1; 4 is a flowchart showing a series of operations of the stereolithography apparatus 1; 4 is a flowchart showing a series of operations of the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; FIG. 3 is a side view schematically showing a state in the middle of modeling in the stereolithography apparatus 1; 4 is a cross-sectional view showing the detailed configuration of the slurry discharge pump 40. FIG. 4 is a diagram for explaining the arrangement relationship between a slurry discharge pump 40 and a screw 42; FIG. 4 is a diagram illustrating a detailed configuration of a pump scraper 43; FIG. FIG. 3 is a cross-sectional view showing the detailed configuration of a secondary supply unit 45 (slurry supply device 100). FIG. 4 is a diagram for explaining an ejection mode when multi-line ejection is performed in the stereolithography apparatus 1;

<Overview of equipment>
FIG. 1 is a perspective view showing a schematic configuration of an optical shaping apparatus 1 according to this embodiment. FIG. 2 is a functional block diagram of the essential parts of the stereolithography apparatus 1. As shown in FIG. FIG. 3 is a side view showing the layout relationship of main components in the stereolithography apparatus 1. As shown in FIG.

The stereolithography apparatus 1 according to the present embodiment roughly applies a paste-like material called slurry, which is obtained by kneading a photocurable monomer resin (liquid) with ceramic powder (for example, alumina), on a modeling table. , irradiating the obtained slurry film (layer) with light such as a laser or LED from above to expose a necessary area to cure the resin, repeating the sequentially laminated slurry film, It is an apparatus for obtaining a three-dimensional model (laminate). In addition, hereinafter, the exposure based on the pattern data for exposure performed in the stereolithography apparatus 1 is also referred to as drawing.

The optical shaping apparatus 1 mainly includes a shaping table 11, an auxiliary table 12, an exposure unit 20, a recoating unit 30, a slurry discharge pump 40, and a controller C (FIG. 2). In FIG. 1, right-handed xyz coordinates are given with the direction from the auxiliary table 12 toward the modeling table 11 being the positive direction of the y-axis, and the upward direction of the vertical direction being the positive direction of the z-axis (the same applies hereinafter). ).

The modeling table 11 is a rectangular table in plan view on which modeling is performed. The modeling table 11 can be raised and lowered in the z-axis direction as indicated by an arrow AR1. Such elevating operation is realized by the z-axis elevating mechanism 11M (FIG. 2). Specifically, as shown in FIG. 3, it is mainly moved between an initial position 11a (height h1), an ejection/exposure position 11b (height h2), and a recoating position 11c (height h3). be done.

Roughly speaking, the build table 11 is raised from the initial position 11a during slurry application and subsequent exposure, and each time the formation of the build progresses (each time the formation of each layer is completed), the necessary amount is lowered.

The modeling table 11 preferably has a modeling area of at least 600 mm x 600 mm, more preferably 650 mm x 650 mm or more, in order to be able to model a large-sized modeled object.

The molding table 11 also has a plurality of suction grooves (grooves) 11g on its upper surface. 11 g of several adsorption grooves are used when fixing the film (for example, protective film) laid on the upper surface of the modeling table 11 at the time of modeling. 11 g of several adsorption|suction groove|channels are provided over the whole modeling area. More specifically, the plurality of suction grooves 11g communicate with an air suction blowout mechanism 11AR (FIG. 2), and under the control of a controller C (an example of control means of the present disclosure), air is The film is vacuum-adsorbed by the adsorption blow-out mechanism 11AR applying a negative pressure to the plurality of adsorption grooves 11g.

Note that when the modeled object is transported after completion, the vacuum suction is canceled under the control of the controller C, and instead air is supplied from the air suction blowing mechanism 11AR to the suction groove 11g. As a result, the modeled object is slightly lifted from the modeling table 11 together with the film, so that the film can be easily gripped by the film gripper 52, which will be described later, and transported together with the modeled object thereon.

The auxiliary table 12 is a table having a rectangular shape in a plan view and used for preparing a film and transporting a finished model. The auxiliary table 12 has substantially the same plane size as the modeling table 11 . The auxiliary table 12 is placed and supported on a fixed portion (support) 12F, and is provided at the same height h1 as the initial position 11a of the modeling table 11, as shown in FIG. The auxiliary table 12, together with the fixing portion 12F, can move forward and backward in the y-axis direction as indicated by an arrow AR2. Specifically, it moves back and forth between a normal position 12a and an adjacent position 12b that is flush with and adjacent to the modeling table 11 at the initial position 11a on the positive side in the y-axis direction. Such forward/backward movement is realized by a y-axis moving mechanism 12M (FIG. 2) provided in the fixed portion 12F. The y-axis movement mechanism 12M has an actuator.

The auxiliary table 12 also has a plurality of suction grooves (grooves) 12g on its upper surface. 12 g of several adsorption|suction groove|channels are used when fixing the film laid|layed on the upper surface of the modeling table 11 at the time of modeling once prior to laying|laying which concerns. More specifically, the plurality of suction grooves 12g communicate with the air suction blow-out mechanism 11AR (FIG. 2) through the fixing portion 12F, and the air suction blow-out mechanism 11AR is connected to the plurality of suction grooves 12g in a state where the film is laid. By applying a negative pressure, the film is vacuum-sucked. The film once laid on the auxiliary table 12 is conveyed to the modeling table 11 by a suction pad unit 51, which will be described later.

Further, the auxiliary table 12 is detachable from the fixed portion 12F at the normal position 12a. That is, it has a portability that allows it to be separated from the y-axis movement mechanism 12M and the air suction blowout mechanism 11AR and carried. In the stereolithography apparatus 1 according to the present embodiment, by utilizing the portability of the auxiliary table 12, the modeled object transferred to the auxiliary table 12 after completion can be transported together with the auxiliary table 12. there is

For example, as shown in FIG. 3, the air suction blowout mechanism 11AR includes a vacuum pump (an example of the suction means of the present disclosure) PP1, a compressed air pump (an example of the air supply means of the present disclosure) PP2, and switching valves VLV1 and VLV2. Prepare. The switching valves VLV1 and VLV2 operate as switching devices for switching between suction by the vacuum pump PP1 and air blowing by the compressed air pump PP2 on the modeling table 11 and the auxiliary table 12, respectively. The controller C controls the vacuum pump PP1, the compressed air pump PP2, and the switching valves VLV1 and VLV2 to switch the vacuum suction/air floating of the film.

The plurality of suction grooves 11g are distributed over a plurality of mutually independent zones zn, and switching valves VLV1 and VLV2 also switch between suction by the vacuum pump PP1 and air blowing by the compressed air pump PP2 for each zone zn. It's like At the time of transportation, the suction groove 11g of the appropriate zone zn is selectively used according to the size and position of the modeled object. In FIG. 1, the rectangular suction grooves 11g and 12g are arranged two-dimensionally, but this is only an example, and the plurality of suction grooves 11g and 12g may be arranged in other manners such as stripes. may be provided.

An exposure unit (an example of exposure means) 20 is a light source provided with one or more projectors 21 for emitting light. The projector 21 includes light-emitting elements such as lasers and LEDs. The exposure unit 20 can move back and forth in the y-axis direction as indicated by an arrow AR3. Such forward/backward movement is realized by a pair of left and right linear motors 20M (FIG. 2), which are not shown in FIG.

The projector 21 is an element that performs pattern exposure (projection) on the slurry coating film formed on the modeling table 11 . The exposure by the projector 21 is performed by, for example, the DMD projection method. That is, the projection (exposure) pattern (data) is fed in while moving the projector 21 stepwise or continuously in the y-axis direction to project the pattern. After completing the movement in one direction, the projector 21 is moved in the x-axis direction by a predetermined distance, and performs exposure while moving in the opposite direction in the y-axis direction. That is, in the present embodiment, strip-like exposure is performed for each region of a predetermined width. These operations are repeated until exposure is completed for all modeling target areas in each layer.

More specifically, the projector 21 is arranged with a slight inclination with respect to the y-axis direction, and is moved in such an inclined posture. Therefore, the method performed by the stereolithography apparatus 1 according to the present embodiment is also called an oblique exposure method.

The projector 21 is arranged such that its lower end is located at a height above the z-axis separated from the ejection/exposure position 11b of the modeling table 11 by a predetermined projector working distance (Proj_WD).

The stereolithography apparatus 1 shown in FIG. 1 has four projectors 21 (21a to 21d) equidistantly arranged in the x-axis direction, and these projectors perform exposure in synchronism.

Movement of the projector 21 in the y-axis direction is achieved by moving the entire exposure unit 20 . On the other hand, movement in the x-axis direction indicated by arrow AR4 is realized by x-axis movement mechanism 21M (FIG. 2). The x-axis movement mechanism 21M has an actuator.

The recoat unit 30 is a unit in which a recoater (an example of the sweeping means of the present disclosure) 31, a slurry discharge pump (an example of the discharge means of the present disclosure) 40, and a screw 42 are integrated. The recoat unit 30 can move back and forth in the y-axis direction as indicated by an arrow AR6. Such forward/backward movement is realized by a pair of left and right linear motors 30M (FIG. 2), which are not shown in FIG. Preferably, the guide rail of the linear motor 30M is shared with the linear motor 20M for moving the exposure unit 20.

The recoater 31 is a blade-shaped member that sweeps the slurry discharged onto the modeling table 11 . The recoater 31 is attached to the recoat unit 30 so that its longitudinal direction extends in the x-axis direction, and the size in the x-axis direction is substantially the same as the size of the modeling table 11 in the x-axis direction. . The recoater 31 moves in the y-axis direction due to the movement of the recoat unit 30 while maintaining a predetermined distance from the modeling table 11, and spreads the slurry discharged onto the modeling table 11 in the y-axis direction to form a slurry film.

The used recoater 31 is cleaned by a cleaning unit (cleaner) 32 . The cleaning unit 32 is disposed below one end of the recoater 31 so as to move up and down between a use height 32a, a modeling stand-by height 32b, and a stand-by height 32c, as indicated by an arrow AR7. there is In addition, the cleaning unit 32 is movable in the x-axis direction as indicated by an arrow AR8 at the use height 32a. The cleaning unit 32 may include a spatula, a brush, or the like, or may have another configuration.

After the recoater 31 is used, the cleaning unit 32 arranged at the use height 32 a moves in the x-axis direction while being in contact with the recoater 31 , thereby removing the slurry adhering (remaining) on the recoater 31 . Thereby, the recoater 31 is cleaned.

Thereafter, when slurry application is repeated, the cleaning unit 32 waits at the standby height 32b during modeling. After the coating is completely finished, it stands by at the standby height 32c until the next use.

Movement of the cleaning unit 32 in the z-axis direction indicated by the arrow AR7 is realized by the z-axis elevating mechanism 31M1 (FIG. 2). Movement of the cleaning unit 32 in the x-axis direction indicated by the arrow AR8 is realized by the x-axis movement mechanism 31M2 (FIG. 2). The x-axis movement mechanism 31M2 has an actuator.

The slurry discharge pump 40 is a pump having a function of storing slurry for modeling inside and discharging the slurry onto the modeling table 11 during modeling. The slurry discharge pump 40 can be moved in the y-axis direction by the movement of the recoating unit 30, and can be moved in the x-axis direction as indicated by the arrow AR9 by the x-axis movement mechanism 40M (FIG. 2). The x-axis movement mechanism 40M has an actuator.

The slurry discharge pump 40 is provided with a slurry level sensor (an example of the monitoring means of the present disclosure) 41 for detecting the liquid level of the slurry stored inside, and a screw 42 responsible for discharging the slurry. The slurry level sensor 41 is, for example, a non-contact sensor such as a laser sensor or an ultrasonic sensor that irradiates a laser beam toward the slurry liquid surface and receives reflected light.

The screw 42 is rotated by a screw drive motor 42M. Slurry is discharged from the lower end of the slurry discharge pump 40 by rotating the screw 42 inside the slurry discharge pump 40 . The amount of slurry discharged from the slurry discharge pump 40 changes according to the rotation speed of the screw 42 . The discharge height h4, which is the distance between the lower end of the slurry discharge pump 40 and the discharge/exposure position 11b of the modeling table 11, is appropriately set in consideration of the slurry material and the like.

Moreover, the slurry discharge pump 40 is further equipped with a pump scraper 43 .

The pump scraper 43 moves up and down within the slurry discharge pump 40 as indicated by an arrow AR10 to scrape off the slurry material adhering to the inner wall surface of the slurry discharge pump 40, thereby leveling the liquid surface of the slurry. function.

The stereolithography apparatus 1 further includes a secondary supply section (an example of supply means of the present disclosure) 45 as a slurry supply source for the slurry discharge pump 40 . The amount of slurry to be used increases as the size and area of the modeled object increases. However, it is not desirable to move the excessively heavy slurry discharge pump 40 to perform the discharge operation in terms of operational stability, discharge accuracy, productivity, and the like.

Therefore, in the stereolithography apparatus 1 according to the present embodiment, the controller C monitors the remaining amount of slurry in the slurry discharge pump 40 using the slurry level sensor 41, and detects that the remaining amount is less than the specified value. At the timing, the slurry discharge pump 40 is moved to a predetermined replenishment position 40b, and the slurry is replenished from the secondary supply section 45 to the slurry discharge pump 40. As shown in FIG. Preferably, the secondary supply 45 is a removable mechanism for when material replacement or cleaning is required.

Details of the slurry discharge pump 40 and the secondary supply section 45 will be described later.

Furthermore, the stereolithography apparatus 1 includes, as components responsible for moving the film, a suction pad unit (suction carrier) 51 which is an example of the suction transport means of the present disclosure, and a film gripper 52 which is an example of the holding transport means of the present disclosure. and

The adsorption pad unit 51 is a film adsorption mechanism for adsorbing a film set on the auxiliary table 12 and transferring it onto the modeling table 11 . Under the control of the controller C, the suction pad unit 51 normally waits at a standby position 51a (FIG. 3) set below the standby position of the exposure unit 20, and when in use, the exposure unit is held by pin fitting (not shown). 20 is merged at the bottom. Then, as the exposure unit 20 moves, the auxiliary table 12 moves in the negative y-axis direction and moves to the adjacent position 12b. The end of the film in the positive y-axis direction is sucked. By moving the exposure unit 20 in the positive direction of the y-axis while maintaining such a suction state, the suction pad unit 51 moves to the end position 51 c , thereby conveying the film to the modeling table 11 .

The adsorption and release of the film are performed by moving the adsorption pad unit 51 up and down as indicated by an arrow AR5. Such vertical movement is realized by the air cylinder 51AS. Air for driving is supplied from a joint port (not shown) provided in the exposure unit 20 .

The film grippers 52 are a pair of film gripping mechanisms used when transporting the completed modeled object from the modeling table 11 to the auxiliary table 12 . Under the control of the controller C, the film gripper 52 normally waits at standby positions 52a (FIG. 3) set below the standby position of the recoat unit 30 at both ends of the auxiliary table 12 in the x-axis direction. When used, it is combined with the lower portion of the recoat unit 30 by pin fitting (not shown). Along with the movement of the recoat unit 30, it moves in the positive direction of the y-axis, and at gripping positions 52b set at both ends of the modeling table 11 on the negative side in the y-axis direction, the film, together with the modeled object, is air-floated. Grasp the ends. By moving the recoat unit 30 in the negative direction of the y-axis while maintaining such a gripping state, the film and the modeled object placed on the upper surface thereof are conveyed to the auxiliary table 12 . At that time, the zones zn to which the suction grooves 11g and 12g that receive the supply of air from the compressed air pump PP2 belong are switched sequentially according to the movement of the modeled object. That is, only the suction grooves 11g and 12g necessary for air-floating the moving modeled object are used sequentially and selectively.

When the modeled object is transported, the air supply from the suction grooves 11g and 12g that are not located directly under the film or from the suction grooves 11g and 12g that are not located directly under the modeled object may be stopped. As a result, a large amount of air is prevented from being blown out from the suction grooves 11g and 12g, which are less loaded and have no film or shaped object above them, and the suction grooves located directly below the shaped object necessary to float the shaped object. Sufficient air blowing can be performed from 11g and 12g. The controller C may determine the zone to which air is supplied according to the transport distance of the film, or detect the position of the film and/or the object with a sensor and determine the zone to which air is supplied according to the detection result. You may

In addition, the stereolithography apparatus 1 further includes a fan filter unit (FFU) 15 and the like. The FFU 15 is a mechanism for maintaining cleanliness inside the optical forming apparatus 1 .

All the operations of the respective parts of the stereolithography apparatus 1 having the above configuration are controlled by the controller C (FIG. 2). Controller C can be implemented by a general-purpose or dedicated computer.

Preferably, the controller C includes a modeling data processing unit C1 that converts the three-dimensional shape data (CAD data) of the object to be shaped into projection (exposure) pattern data that can be used for strip-shaped exposure for each layer by the projector 21. . The slice data generated by the modeling data processing unit C<b>1 is sequentially used for pattern exposure by the projector 21 .

Note that the modeling data processing section C1 may be provided as a computer separate from the controller C. FIG.

<Operation of stereolithography device>
4 to 6 are flowcharts showing a series of operations of the stereolithography apparatus 1 when a modeled object is formed by the stereolithography apparatus 1. FIG. 7 to 21 are side views schematically showing states in the middle of modeling in the optical shaping apparatus 1. FIG.

First, each part/unit is moved to the initial position (standby position) (step S1). Specifically, the modeling table 11, the auxiliary table 12, the exposure unit 20, and the recoat unit 30 are arranged at initial positions.

Subsequently, as shown in FIG. 7, the operator manually places (stacks) a film F (protective sheet or simply sheet) on the auxiliary table 12 (step S2). The film F is placed so as to cover the entire surface of the auxiliary table 12 . The placed film F is vacuum-adsorbed to the auxiliary table 12 by applying a negative pressure to the plurality of adsorption grooves 12g by the air adsorption/blowing mechanism 11AR. Also, the auxiliary table 12 on which the film F is placed is moved from the normal position 12a to the adjacent position 12b, as shown in FIG.

When the film F is set, the suction pad unit 51 is combined with the exposure unit 20 by pin fitting (step S3). At this time, air is supplied from the exposure unit 20 side to the air cylinder 51AS by joint connection.

Subsequently, as the exposure unit 20 moves in the negative direction of the y-axis, the suction pad unit 51 moves to the suction position 51b (step S4). The suction pad unit 51 is driven by the air cylinder AS to descend, and suction the film F as shown in FIG. 9 (step S5). Along with this suction, the vacuum suction of the film F to the auxiliary table 12 is released.

The exposure unit 20 moves in the positive y-axis direction while the suction pad unit 51 is holding the film F (step S6). As a result, the film F is conveyed onto the modeling table 11 as shown in FIG. The exposure unit 20 stops when the suction pad unit 51 moves to the end position 51c and the film F covers the entire modeling table 11.例文帳に追加

Simultaneously with such a stop, the air suction blowing mechanism 11AR applies negative pressure to the plurality of suction grooves 11g, so that the film F is vacuum-sucked to the modeling table 11 (step S7). On the other hand, the suction by the suction pad unit 51 is released (step S8).

Subsequently, the exposure unit 20 is moved to the standby position, and the pin engagement is released, thereby separating the suction pad unit 51 from the exposure unit 20 (step S9). At the same time, as shown in FIG. 11, the auxiliary table 12 at the adjacent position 12b is moved to the normal position 12a (step S10). Alternatively, the operator may place the film F directly on the modeling table 11 .

Next, strip data is generated from the three-dimensional shape data (CAD data) of the object to be shaped in the shaping data processing unit C1 (step S11), and projection (exposure) pattern data is generated based on the strip data ( step S12). Here, the strip data is partial data of the three-dimensional shape data corresponding to the area where the projector 21 performs exposure by moving once in the y-axis direction.

The generated projection (exposure) pattern data is transferred to the projector 21 (step S13). While the transfer is being performed (NO in step S14), slurry application processing is performed in parallel.

Specifically, following the movement of the auxiliary table 12 to the normal position 12a (step S10), the modeling table 11 to which the film F is fixed by suction is raised to the ejection/exposure position 11b at the height h2 (step S15).

Subsequently, by moving the recoating unit 30 in the positive direction of the y-axis, the slurry discharge pump 40 is moved to a predetermined slurry discharge position. The slurry discharge position may be appropriately set according to the size and area of the object to be shaped, but is usually set on the back side of the shaping table 11 in the y-axis direction, as shown in FIG. At the slurry discharge position, the slurry discharge pump 40 with the lower end discharge port 44 in the open state is moved in the x-axis direction, and the screw 42 is rotated at a required number of revolutions, thereby discharging a predetermined amount of slurry. is discharged in a line on the modeling table 11 (step S16).

The number of pairs of the ejection start point and the ejection end point is not limited to one, and a plurality of pairs may be set with an appropriate interval Δp in the y-axis direction. Such a slurry discharge mode is called multi-line discharge. The discharging operation is performed until all the required amount of slurry is discharged (step S17). When multi-line discharge is performed, the distance between the lower end of the slurry discharge pump 40 and the lower end of the recoater 31 must be set appropriately so that the tip of the recoater 31 does not touch the discharged slurry.

The remaining amount of slurry in the slurry discharge pump 40 at the time of discharge is constantly monitored by the slurry level sensor 41, and when the amount falls below a specified amount, the slurry is discharged from the secondary supply unit 45 at an appropriate timing such as between discharges. be replenished.

When the discharge of the slurry is completed (YES in step S17), the discharge port 44 is closed by a shutter or the like, and then the recoat unit 30 moves to the recoat start position (step S18). Following the movement of the recoating unit 30, the modeling table 11 is raised from the ejection/exposure position 11b to the recoating position 11c (step S19). At that time, the distance between the recoating position 11c and the lower end of the recoater 31 is set to the coating height h5 corresponding to the thickness of the slurry film SLF to be formed. The recoating start position is usually set such that the recoater 31 is located further to the positive side in the y-axis direction than the slurry discharge range.

When the modeling table 11 reaches the recoating position 11c, the recoating unit 30 moves in the negative y-axis direction. As a result, as shown in FIG. 13, the slurry discharged onto the modeling table 11 is swept by the recoater 31 to form a slurry film SLF having a predetermined thickness (step S20).

When the recoater 31 moves a predetermined distance in the y-axis direction to form the slurry film SLF in a predetermined range on the modeling table 11, the recoat unit 30 moves further in the negative y-axis direction to the standby position (recoater cleaning position). ) (NO in steps S21 and S22).

When the recoat unit 30 reaches the standby position (recoater cleaning position) (YES in step S22), the cleaning unit 32, which has been waiting at the standby height 32c until then, moves to the cleaning position (use height) as shown in FIG. 32a) (step S23). The cleaning unit 32 reciprocates in the x-axis direction, thereby scraping off the slurry adhering (remaining) on the recoater 31 (step S24). That is, the recoater 31 is cleaned.

After cleaning is completed, the cleaning unit 32 retreats to the initial position in the x-axis direction (step S25), and further retreats to the standby height 32b during modeling (step S26).

On the other hand, after the formation of the slurry film SLF by the recoater 31 is completed and the recoat unit 30 is moved to the cleaning position (YES in step S22), the pattern exposure by the projector 21 proceeds in parallel with the cleaning of the recoater 31. do.

Specifically, first, the modeling table 11 formed with the slurry film SLF is moved from the recoating position 11c to the ejection/exposure position 11b (step S28). Subsequently, the exposure unit 20 is arranged at the exposure start position (step S29). More specifically, the exposure unit 20 is moved in the negative y-axis direction to adjust the position of the projector 21 in the x-axis direction.

When the projector 21 is positioned at a predetermined exposure start position, the combination of continuous reciprocating movement of the exposure unit 20 in the y-axis direction and stepwise movement of the projector 21 in the x-axis direction based on the exposure pattern data that has been transferred in advance. , and as shown in FIG. 15, the slurry film SLF is exposed strip by strip with the exposure light EL emitted from the projector 21 (step S30).

More specifically, when the exposure of one strip is completed by moving the exposure unit 20 once in the y-axis direction, and there is still a strip to be exposed (drawn) (NO in step S31), the next strip data is created (step S11), exposure pattern data is generated (step S12), and exposure pattern data is transferred (steps S13 and S14). After that, the projector 21 is stepped in the x-axis direction, and the exposure unit 20 is moved in the y-axis direction in the direction opposite to that during the most recent drawing, thereby performing exposure based on the newly generated exposure pattern data. will be

When drawing is completed for all strips (YES in step S31), the exposure unit 20 retreats to the standby position (step S32). At that time, the projector 21 also moves to the initial position. Normally, the cleaning of the recoater 31 (step S24) is completed by the time drawing is completed for all strips, and the cleaning unit 32 has moved to the standby height 32b during modeling (step S27). YES).

After that, if there is a need to write for another layer (slurry film SLF) (NO in step S33), the processes after step S11 are repeated. That is, the formation of the slurry film SLF and the pattern exposure are repeated. In this case, the slurry film SLF is formed on the most recently exposed slurry film SLF. FIG. 16 shows a state in which a modeled object (laminated body LB of slurry films SLF) is completed in a form buried in unexposed portions by completing exposure of all layers.

When the modeled object is completed (YES in step S33), the modeling table 11 is lowered to the initial position 11a as shown in FIG. 17 in order to remove the unexposed portion and take out the modeled object (step S34). At the same time, the cleaning unit 32, which has been positioned at the modeling standby height 32b until then, descends to the standby height 32c (step S35).

Further, the film gripper 52 located at the standby position 52a is combined with the recoat unit 30 by pin fitting (step S36). Subsequently, the recoat unit 30 moves in the positive direction of the y-axis, and the film grippers 52 are placed at the gripping positions 52b of both ends of the molding table 11 on the negative side in the y-axis direction (step S37). At this position, the film gripper 52 grips the end of the film F laid under the object on the modeling table 11 (step S38).

On the other hand, in parallel with such gripping, the auxiliary table 12 waiting at the normal position 12a is moved to the adjacent position 12b (step S39). As a result, the modeling table 11 on which the modeled article and the film F are placed and the auxiliary table 12 are flush with each other. In this state, the vacuum suction of the film F to the modeling table 11 is canceled by the air suction blowing mechanism 11AR applying a negative pressure. Air is sequentially and selectively supplied to the suction grooves 11g and 12g (step S40).

FIG. 18 shows how such air is supplied. First, under the control of the controller C, the air suction blowout mechanism 11AR supplies air to the suction groove 11g in the zone corresponding to the position of the modeled object. When the air supply is started, the rear surface of the film F, which has been in contact with the modeling table 11 until then, receives an upward force from the air, and the whole or a part of the film F together with the modeled object slightly floats. As a result, all or part of the film F and the modeled object are in a non-contact state with the modeling table 11, so that they can be easily transported by applying force in the horizontal direction. In the example of FIG. 18, the blowing of air from the suction groove 12g of the auxiliary table 12 to which the modeled object has not yet reached is stopped.

When the non-contact state is achieved, the film gripper 52 moves in the negative direction of the y-axis toward the standby position 52a by moving the recoat unit 30. As shown in FIG. Since the film gripper 52 grips the film F floating by the air, the film F and the modeled object thereon move from the modeling table 11 to the auxiliary table 12 as the film gripper 52 moves. (step S41).

FIG. 19 and FIG. 20 show the state of such movement. As shown in FIG. 19, when transporting the model placed on the film F, the controller C causes the air suction blowing mechanism 11AR to supply air from the suction grooves 11g and 12g in the zones corresponding to the position of the model. Then, the supply of air from the suction grooves 11g and 12g outside the zone is stopped. As a result, as shown in FIG. 20, the modeled object is transported in a state where it is lifted from the modeling table 11 and the auxiliary table 12 together with part or all of the film F. As shown in FIG.

When the movement of the film F and the modeled object to the auxiliary table 12 is completed, the grip of the film F by the film gripper 52 is released (step S42). Subsequently, the recoat unit 30 formed by combining the film gripper 52 is moved in the y-axis direction and returned to the standby position (step S43), and the film gripper 52 is released from the recoat unit 30 (step S44). ).

Further, the auxiliary table 12 on which the modeled object is placed together with the film F is returned from the adjacent position 12b to the normal position 12a. The auxiliary table 12 is detachable from the fixed portion 12F at the normal position 12a. As shown in FIG. It is transferred to the prepared carriage CV and conveyed to the outside of the stereolithography apparatus 1 (step S45). As a result, the object can be transported without being in direct contact with the object, so that the risk of damage or the like is reduced, and stable transport is possible.

The above is the procedure for creating a modeled object and then taking it out, which is realized by the optical shaping apparatus 1 according to the present embodiment. The stereolithography apparatus 1 according to the present embodiment is particularly characterized in that even when a large-sized object is created, it can be taken out easily and reliably.

Specifically, air can be supplied to a plurality of suction grooves for vacuum suction provided on the surface of the modeling table 11 for modeling. In addition to the modeling table 11 , an auxiliary table 12 is provided as an outlet for the molded object, and the auxiliary table 12 can also supply air in the same manner as the molding table 11 . As a result, even a modeled object with a large size and large area can be floated by air and kept in non-contact with the modeling table 11 and the auxiliary table 12, so that the film spread under it can be gripped. Horizontal transportation (transfer) of the modeled object is facilitated.

In addition, the auxiliary table 12 is detachably attached to the fixing portion 12F. In other words, the auxiliary table 12 itself has portability. Therefore, the modeled object transferred from the modeling table 11 can be transported to the outside together with the auxiliary table 12 . As a result, since the object can be transported without coming into contact with the modeled object, it is possible to stably transport the object with less risk of breakage or the like.

<Detailed configuration of slurry discharge pump>
FIG. 22 is a cross-sectional view showing the detailed configuration of the slurry discharge pump 40. As shown in FIG. FIG. 23 is a diagram for explaining the positional relationship between the slurry discharge pump 40 and the screw 42. As shown in FIG.

As described above, the slurry discharge pump 40 is a pump having a function of storing therein the slurry SL for modeling and discharging the slurry SL onto the modeling table 11 or the film during modeling.

As shown in FIG. 22, the slurry discharge pump 40 includes a funnel-shaped discharge portion 40A tapered at the lower end, and a cylindrical storage portion 40B continuing to the upper portion of the discharge portion 40A. A cap 40C is attached to the tip of the ejection portion 40A. The cap 40C has a rotary slurry stopper 40D inside. Since the viscosity of the slurry SL also changes depending on the temperature, there is a possibility that the viscosity of the slurry SL will drop due to the temperature rise around the apparatus, causing dripping. The slurry stopper 40D is provided to prevent such dripping of the slurry SL.

A discharge port 44 is formed at the lower end of the cap 40C. The discharge port 44 can be switched between an open state and a closed state by a shutter or the like. The hole diameter of the portion through which the slurry SL passes in the cap 40C is preferably 3 mm to 5 mm.

Furthermore, a screw 42 is inserted into the interior of the slurry discharge pump 40 from the storage portion 40B to the discharge portion 40A. When the discharge port 44 is open, the screw 42 is driven to rotate by the screw drive motor 42M, thereby discharging the slurry SL inside the slurry discharge pump 40 through the cap 40C.

More specifically, changing the rotation speed of the screw 42 changes the discharge amount. It is possible to change the overall ejection characteristics depending on the rotation speed by adjusting the distance from the

Since the slurry SL has a high viscosity and does not easily drip, the minimum distance between the inner wall surface of the slurry discharge pump 40 and the outer shape of the screw 42 is set to 1 mm to 2 mm. When the screw 42 is separated from the cap 40C as shown in FIG. 23(a), the distance g1 between the inner wall surface of the discharge portion 40A and the outer shape of the screw 42 corresponds to the minimum distance. When the screw 42 is close to the cap 40C, the distance g2 between the cap 40C and the outer shape of the screw 42 corresponds to the minimum distance.

As shown in FIG. 23(a), when the screw 42 is separated from the cap 40C, the change in the discharge amount with respect to the number of revolutions becomes small, and the discharge amount becomes constant (saturates).

The screw 42 may have a unidirectional helix, or may be one in which the direction of the helix in the lower part and the direction of the helix in the upper part are opposite to each other from the vicinity of the center in the longitudinal direction. In the latter case, if the direction of rotation of the screw 42 at the bottom is the direction to discharge the slurry SL from the cap 40C, the direction of rotation of the screw 42 at the top is the direction to send the slurry SL upward and stir it. Become. When such agitation is performed, the upper surface of the slurry SL stored in the storage part 40B is suppressed from becoming concave, so the slurry level sensor 41 can more appropriately detect the remaining amount of slurry. Furthermore, when such agitation is performed, the viscosity of the slurry SL is also made uniform.

The slurry discharge pump 40 is also provided with the pump scraper 43 as described above. FIG. 24 is a diagram illustrating the detailed configuration of the pump scraper 43. As shown in FIG.

As shown in FIG. 24, the pump scraper 43 includes a rod-shaped support portion 43a and a double annular body portion 43b provided at the lower end portion of the support portion 43a. Further, the pump scraper 43 can be moved up and down by an elevating mechanism (actuator) 43d (FIG. 22) connected to the support portion 43a.

The pump scraper 43 is inserted into the reservoir 40B of the slurry discharge pump 40 and used with the screw 42 fitted in the central portion thereof. Specifically, the support portion 43a is vertically moved by the elevating mechanism 43d at an appropriate timing while the screw 42 is being operated to discharge the slurry SL or while the slurry SL is not being discharged. Along with the vertical movement, the body portion 43b scrapes off the slurry SL adhering to the inner wall surface of the slurry discharge pump 40, and uniformizes the liquid surface of the slurry SL in the storage portion 40B. Thereby, the slurry level sensor 41 can appropriately monitor the remaining amount of slurry.

The pump scraper 43 is made of, for example, metal and/or hard resin. The reason is that the pump scraper 43 itself may be bent by the resistance force received from the high-viscosity slurry SL during operation.

The pump scraper 43 is provided at a distance of 1 mm to 3 mm from the inner wall surface of the reservoir 40B. In such a case, since the highly viscous slurry SL acts like a lubricant, direct friction between the two usually does not occur.

Incidentally, if the area of the pump scraper 43 is large, the resistance due to the slurry SL increases. On the other hand, it is desirable that the viscosity of the slurry SL in the slurry discharge pump 40 is as uniform as possible in order to keep the discharge speed highly constant. If the outer diameter of is greatly different from the inner diameter of the reservoir 40B, the uniformity of the viscosity of the slurry SL may be lost. This is because the softening of the slurry SL due to the shear stress of the pump scraper 43 reaches only a distance of several centimeters from the pump scraper 43 .

In the present embodiment, in view of this point, the main body portion 43b of the pump scraper 43 is made into a double annular shape, and the uniformity of the viscosity of the slurry SL is maintained while suitably ensuring the function of scraping off the slurry SL. properly secured.

Preferably, the outer edge of the body portion 43b of the pump scraper 43 is provided with a thin resin film 43c. In such a case, the scraping performance of the slurry SL is enhanced. Further, even if the resin film 43c were to come into contact with the inner wall of the reservoir 40B, it would be the resin film 43c that would be worn, and the components of the resin film 43c would be mixed into the slurry SL and even into the modeled object. However, since the resin component is volatilized in the sintering process of the ceramic component performed as a post-process, such contamination does not pose a problem in the final product.

<Detailed Configuration of Secondary Supply Unit>
FIG. 25 is a cross-sectional view showing the detailed configuration of the secondary supply section 45. As shown in FIG. In addition, in the subsequent description based on FIG. 25, the secondary supply part 45 is called the slurry supply apparatus 100. As shown in FIG.

The slurry supply device 100 comprises a screw 101 made of resin, a pipe 102 in which the screw 101 is accommodated, and a bearing provided at one end of the screw 101 for rotating the screw 101 around its axis within the pipe 102. A portion 103, a base 104 that supports the slurry supply device 100, a supply portion 105 that is connected to the tip (upper end) of the pipe 102 and serves as a supply port of the slurry SL to the outside, and the slurry SL is stored. It mainly includes a slurry container 106 having a supply path 106b connected to the lower end of a reservoir 106a.

In the slurry supply device 100 , the screw 101 rotates to convey the slurry SL stored in the slurry container 106 through the pipe 102 and supply it to the outside through the supply section 105 . Thereby, it is possible to replenish the slurry discharge pump 40 with the slurry SL from the tip 105 a of the supply part 105 .

More specifically, the pipe 102 is attached to the base 104 so as to be inclined at an angle of 30 degrees or more and 60 degrees or less from the horizontal plane. Become. Even if the inclination angle of the pipe 102 is made larger than 60°, it is not impossible to transport the slurry SL. The larger the transport length in 102 and supply unit 105, the smaller the transport amount per unit time.

The difference between the outer diameter of the screw 101 and the inner diameter of the pipe 102 is 1 mm to 2 mm. This is because the slurry SL has thixotropic properties, so when the screw 101 rotates, the viscosity is low at a location far from the adhesion surface, but the shear stress does not easily reach the adhesion surface. . By setting the difference between the outer diameter of the screw 101 and the inner diameter of the pipe 102 to 2 mm or less, shear stress can be applied to the adhesion surface. On the other hand, by setting the difference to 1 mm or more, the possibility of contact between the screw 101 and the pipe 102 can be reduced.

Also, the pitch ps of the screw 101 is 20 mm to 40 mm. As the pitch ps is increased, the highly viscous slurry SL adhering to the screw 101 decreases from around 20 mm, and the amount of slurry conveyed per unit pitch increases significantly. On the other hand, when the pitch ps is greater than 40 mm, the amount of slurry conveyed is saturated irrespective of the value of the pitch ps if the number of revolutions is the same. Therefore, it is preferable that the pitch ps of the screw 101 is 20 mm to 40 mm from the viewpoint of efficiency of slurry transportation.

A pipe made of metal can be used for the pipe 102 . This is because the slurry SL adheres to the inner surface of the pipe 102 as a film when the slurry supply device 100 is used, and the ceramic component contained in the slurry SL rubs against the inner wall of the pipe 102, which may cause the pipe 102 to wear. This is because it is of low quality.

A bearing portion 103 is provided at the lower end portion of the screw 101 . The bearing portion 103 has two stages of bearings separated by a predetermined distance, and these bearings are synchronously driven by driving means (not shown) to rotate the screw 101 in the pipe 102 around its axis. It rotates stably.

The supply unit 105 is composed of a tubular member that can be bent into an arbitrary shape. Preferably, the inner diameter of the supply portion 105 is 12 mm to 18 mm and smaller than the inner diameter of the pipe 102 . Making the inner diameter of the supply unit 105 smaller than the inner diameter of the pipe 102 gives resistance to the slurry SL, which is a factor for reducing the amount of transport per unit time. is improved, and there is an effect of preventing dripping of the slurry SL.

A slurry container 106 for storing the slurry SL is provided in the middle of the inclined pipe 102 and above the portion where the pipe 102 is downwardly supported by the base 104 . The slurry container 106 is provided in a vertical position with a supply channel 106b extending from the lower end of a conical reservoir 106a, and the tip of the supply channel 106b is connected to the pipe 102. The inner diameter of the supply path 106b is substantially the same as the inner diameter of the pipe 102. As shown in FIG. As a result, air inclusion is minimized, and transport of the slurry SL from the slurry container 106 to the pipe 102 is made efficient.

A drain 111 is provided in the vicinity of the base 104 of the pipe 102 . The drain 111 is used when recovering the slurry SL remaining inside the pipe 102 . Roughly speaking, after the slurry SL is discharged through the supply part 105, the inner plug 112 is fitted into the supply path 106b of the slurry container 106 and the drain 111 is opened. can recover the slurry SL remaining in the pipe 102 by rotating in the reverse direction. The drain 111 is used, for example, when it is desired to change the type of slurry SL to be used.

Also, the upper end 107 of the reservoir 106a is configured to be able to be filled with the slurry SL from the outside. Specifically, the slurry case (slurry replenishment container) 108 filled with the slurry SL conveyed from the outside is positioned at the upper end 107 of the reservoir 106a with its opening 109 facing downward. and the opening 109 is continuous with the opening provided in the filling portion 107a. Thus, when the slurry case 108 is placed, the slurry case 108 also serves as a lid for the filling portion 107a. The slurry case 108 is filled with a posture in which the opening 109 faces obliquely downward (for example, the angle formed by the normal direction from the opening surface to the outside and the vertical downward direction exceeds 0 degrees and is less than 90 degrees). It may be placed on the portion 107a. In this case, the slurry supply device 100 may include a stopper that holds the slurry case 108 at a predetermined angle.

A rotating scraper 110 is provided at the upper end of the reservoir 106a to scrape off the slurry SL adhering to the inner wall surface of the mounted slurry case 108 and drop it into the reservoir 106a. The rotary scraper 110 is provided so as to enter the interior of the slurry case 108 through the opening 109 when the slurry case 108 is placed on the filling portion 107a. For the same reason as the pump scraper 43, the rotary scraper 110 is provided at a distance of 1 mm to 3 mm from the inner surface of the slurry case 108, and is driven by a driving means (actuator) (not shown) to move the rotary scraper 110 inside the slurry case 108. Circularly move along the inner wall surface with . As a result, all the slurry SL filled in the slurry case 108 is transferred to the slurry container 106 . For the same reason as the pump scraper 43, the rotary scraper 110 is made of metal or hard resin.

Preferably, a thin resin film 110a is provided on at least the side portion of the rotating scraper 110 that is closer to the slurry case 108 . Similar to the resin film 43c provided on the pump scraper 43 provided in the slurry discharge pump 40, the resin film 110a is provided for the purpose of enhancing the scraping performance of the slurry SL. Also, the resin film 110a is similar to the resin film 43c in that there is no problem even if it is mixed into the modeled object.

More specifically, the slurry case 108 is used to supply the prepared and defoamed new slurry SL to the slurry supply device 100 . The slurry case 108 used for preparation and defoaming may be used as it is for supplying the slurry SL to the slurry supply device 100 . In this case, the operator rotatably fixes the slurry case 108 to the hinge 114 provided in the vicinity of the filling section 107a prior to placing it on the filling section 107a. The hinge 114 faces the slurry case 108 so that the opening 109 faces upward or obliquely upward (for example, the angle formed by the normal direction from the opening surface to the outside and the vertical upward direction is 0 degrees or more and 45 degrees or less). The opening 109 is rotated downward or obliquely downward from the posture.

Instead of using the slurry case 108 for preparation and defoaming, another container containing the prepared and defoamed new slurry SL may be set in the slurry case 108 . In this case, with the opening 109 of the slurry case 108 directed upward or obliquely upward, the operator should make the direction of the opening of the other container and the direction of the opening 109 of the slurry case 108 the same. , set the other container. The slurry case 108 may be rotatably fixed to the filling section 107a by a hinge 114 in advance before another container is set.

The slurry case 108 is placed on the filling section 107a with the opening 109 directed downward or obliquely downward by rotating around the hinge 114 indicated by the arrow AR21. As a result, the handling of the slurry SL from defoaming to filling the slurry container 106 is made more efficient. Note that the rotating scraper 110 is arranged at a position where it does not interfere with the slurry case 108 during such rotating operation. The hinge 114 may be provided with an actuator, and the actuator may be controlled by the controller C to perform the rotational movement.

Further, the inclination of the inner wall surface of the storage portion 106a with respect to the horizontal plane is 45 degrees or more and 70 degrees or less. A rotary scraper 115 is also attached to the reservoir 106a. These are configurations for preventing the slurry from adhering to and staying in the reservoir 106a as much as possible.

The greater the inclination of the reservoir 106a, the more difficult it is for the slurry SL to adhere. By setting the inclination of the inner wall surface of the storage part 106a to 45 degrees or more, it is possible to make it difficult for the slurry SL to adhere to the inner wall. Further, by setting the inclination of the inner wall surface of the storage part 106a to 45 degrees or more, the slurry container 106 can be shortened and the storage efficiency of the slurry SL can be improved. Further, by setting the inclination of the inner wall surface of the reservoir 106a to 70 degrees or less, the filling position of the slurry SL from the slurry case 108 can be lowered to improve workability.

The rotary scraper 115 is for scraping off and dropping the slurry SL adhering to the inner wall surface of the reservoir 106a. For the same reason as the pump scraper 43, the rotary scraper 115 is also provided at a distance of 1 mm to 3 mm from the inner surface of the reservoir 106a, and is driven by a driving means (not shown) to move the rotary scraper 115 inside the slurry case 108. Move around along the inner wall surface. As a result, all the slurry SL filled in the slurry case 108 is transferred to the slurry container 106 . For the same reason as the pump scraper 43, the rotary scraper 115 is also made of metal or hard resin.

Preferably, a thin resin film 115a is provided on at least the side portion of the rotary scraper 115 that is closer to the reservoir 106a. Similar to the resin film 43c and the resin film 110a provided on the pump scraper 43 and the rotary scraper 110, the resin film 115a is provided for the purpose of enhancing the scraping performance of the slurry SL. Also, the resin film 115a is similar to the resin film 43c and the resin film 110a in that there is no problem even if it is mixed into the modeled object.

In the stereolithography apparatus 1 according to the present embodiment, the slurry supply device 100 configured as described above is used as the secondary supply section 45 for supplying slurry to the slurry discharge pump 40 . Specifically, during execution of the modeling process, the slurry level sensor 41 monitors the remaining amount of slurry in the slurry discharge pump 40, and at the timing when the remaining amount becomes less than a specified value, the slurry discharge pump 40 is turned on. , and the screw 101 of the slurry supply device 100 is operated to replenish the slurry discharge pump 40 with slurry. Note that the slurry supply device 100 may be replenished with slurry at an appropriate timing in consideration of the capacity of the slurry case 108 and the like. For example, if the amount of slurry to be replenished to the slurry discharge pump 40 and the capacity of the slurry case 108 are approximately the same, the slurry is supplied from the slurry case 108 to the slurry supply device 100 following the replenishment of the slurry to the slurry discharge pump 40 . may be supplemented.

By having the slurry supply device 100 as the secondary supply unit 45, the stereolithography apparatus 1 according to the present embodiment can supply the modeling material even when modeling a large-sized or large-area modeled object. is suitably ensured.

<Details of multi-line discharge>
FIG. 26 is a diagram for explaining an ejection mode when multi-line ejection is performed in the stereolithography apparatus 1 according to the present embodiment.

In FIG. 26, it is assumed that four lines L1 to L4 are formed by multi-line discharge of slurry in a preset slurry coating region RE. More specifically, the sweep direction of the recoater 31 is the negative direction of the y-axis indicated by the arrow AR22, and the four lines L1 to L4 are separated by a predetermined distance D in order from the farthest side from the initial position of the recoater 31. They are formed apart from each other, and the distance d between the line L1 and the end of the coating region RE is smaller than the distance D. The recoater 31 is adapted to apply the slurry SL to the coating region RE by moving the distance DA from the position of the line L4 closest to the initial position to the end of the coating region RE.

In multi-line discharge, if the discharge amount of slurry is the same for each line, more slurry than necessary may be used in line L4. Expensive slurry can be appropriately used by changing the discharge rate for each line as needed.

For example, in the case of FIG. 26, when a certain layer of slurry is to be applied, it is preferable to vary the discharge amount in each of the lines L1 to L4 depending on whether or not the recoater 31 is coated with the slurry in advance. This is because slurry thickly deposits on the surface of the recoater 31 once it has been swept, so the amount of slurry required for sweeping varies depending on whether or not the slurry adheres. If the new slurry application is the first slurry application, or if the recoater 31 was not cleaned after the previous slurry application, the recoater 31 should be in a state where there is no or little slurry deposited before starting the new slurry application. becomes. Therefore, when the recoater 31 reaches the next line L3 from the first line L4, not all of the slurry in the line L4 is used for the slurry film SLF, but part of it is deposited on the recoater 31. Therefore, the amount of slurry discharged in line L4 includes this deposit. The amount of slurry deposited on the recoater 31 when the recoater 31 reaches the lines L2, L1, and the end of the coating region RE after this is the slurry deposited on the recoater 31 when the recoater 31 reaches the line L3. Approximately the same amount. From this point of view, the amount of slurry discharged from the lines L1 to L3 may be smaller than the amount of slurry discharged from the line L4.

Furthermore, the amount of slurry discharged can also be changed by the moving distance of the recoater 31 during sweeping. For example, in the case of FIG. 26, the distance d between the last swept line L1 and the end of the coating region RE is smaller than the distance D between the lines L1 to L4. This means that the discharge amount in the line L1 may be even smaller than the discharge amounts in the lines L2 and L3. This means that if the moving distance DA of the recoater 31 is not an integer multiple of the inter-line spacing D, the discharge rate in the last swept line is reduced according to the ratio of the spacing d to the inter-line spacing D. It is possible to respond by

Specific methods for differentiating the amount of slurry discharged from each line include changing the speed of the slurry discharge pump 40 and changing the rotation speed of the screw 42 in the slurry discharge pump 40 . In the former case, the higher the moving speed of the slurry discharge pump 40, the smaller the discharge amount. In the latter case, the higher the rotation speed of the screw 42, the greater the discharge amount.

<Other embodiments>
In the embodiment described above, a slurry in which ceramic powder is kneaded into a photocurable resin is used. Alternatively, a slurry containing only a photo-curing resin that does not contain ceramic powder may be used, or a slurry containing other materials such as metal powder instead of ceramic powder may be used.

In the embodiment described above, the plurality of suction grooves 11g and 12g are used as the plurality of air supply ports of the modeling table 11 and the auxiliary table 12. FIG. Alternatively, grooves or holes provided in the molding table 11 and/or the auxiliary table 12 may be used as the air supply ports in addition to the suction grooves 11g and 12g. In this case, the compressed air pump of the air sucking and blowing mechanism 11AR is connected to the plurality of air supply ports. Also, in the modeling table 11 and/or the auxiliary table 12, a plurality of suction holes may be used instead of the plurality of suction grooves 11g and 12g for vacuum suction (and air supply). Further, if the auxiliary table 12 has a plurality of air supply ports separately, the plurality of suction grooves 11g may be omitted.

In the embodiment described above, the film is fixed to the modeling table 11 by suction. Alternatively, the film may be fixed to the modeling table 11 by gripping both ends of the film with grippers and pulling downward.

In the embodiment described above, a transport device (carrier) including the suction pad unit 51 and the film gripper 52 is used as the transport means. Instead of this, a conveying device having a holding device (holder) of another configuration may be used. Also, the conveying device may include an actuator for conveying the film. Further, in the above-described embodiment, the film placed on the auxiliary table 12 may be conveyed to the modeling table 11 while being gripped by a gripper. Alternatively, the film placed on the modeling table 11 may be conveyed to the auxiliary table 12 while being sucked by a suction pad.

In the embodiment described above, the exposure unit 20, which is a light source provided with the projector 21, is used as the exposure means. Alternatively, other light sources such as laser scanning using a galvanomirror or liquid crystal shutter may be used.

In the embodiment described above, the slurry level 41 sensor was used as the monitoring means. Instead of this, as a monitoring means, a timer that measures the time from the start of slurry supply is used, and the controller C, based on the time measured by the timer, at the timing when the remaining amount of slurry is less than the specified value The slurry discharge pump 40 may be refilled with slurry. In addition, other configurations of monitoring means may be used.

In the embodiment described above, the pump scraper 43 having one support portion 43a and a double annular body portion 43b is used. Alternatively, pump scrapers having other shapes may be used. For example, the pump scraper may have two or more support bars, or may have other shaped bodies. Also, the pump scraper may perform other motions such as rotational motion instead of vertical motion.

Alternatively, other configurations of scrapers may be used instead of using rotary scrapers 110, 115 in the embodiments described above.

Reference Signs List 1 stereolithography device 11 molding table 11g, 12g suction groove 12 auxiliary table 12F (auxiliary table) fixed part 20 exposure unit 21 projector 30 recoat unit 31 recoater 32 cleaning unit 40 slurry discharge pump 41 slurry level sensor 42 screw 42M screw drive motor 43 pump scraper 44 discharge port 45 secondary supply unit 51 suction pad unit 52 film gripper 100 slurry supply device 101 screw 102 pipe 103 bearing unit 104 base 105 supply unit 106 slurry container 108 slurry case 109 opening 110 rotary scraper 114 Hinge 115 Rotary scraper F Film LB Laminate SLF Slurry film

In order to solve the above-mentioned problems, the invention of claim 1 is a stereolithography apparatus for obtaining a three-dimensional modeled object, comprising: a modeling table; a discharging means capable of discharging, a sweeping means for sweeping the discharged slurry discharged onto the modeling table to form a slurry film having a predetermined thickness, and an exposure pattern prepared in advance based on three-dimensional shape data. exposure means for exposing a slurry film; monitoring means for monitoring the remaining amount of the slurry in the discharge means during the production of the three-dimensional model; a scraper that applies a shear stress to the slurry to scrape off the slurry to the inner surface of the slurry to make the liquid surface of the slurry uniform; an elevating mechanism that raises and lowers the scraper; and control means for causing the replenishing means to replenish the additional slurry to the discharging means at a predetermined timing when the remaining amount is less than a specified value based on the monitoring result of the monitoring means; characterized by comprising

The invention of claim 2 is the stereolithography apparatus according to claim 1, wherein the supply means is provided with a pipe inclined from a horizontal plane by 30 degrees or more and 60 degrees or less; a screw accommodated in contact and having a pitch of 20 mm to 40 mm ; rotating means for rotating the screw within the pipe; a slurry container; and a supply section connected to the upper end of the pipe, which is a supply port for the additional slurry. and conveying the additional slurry stored in the slurry container and supplying it to the discharge means through the supply unit.
The invention of claim 3 is the stereolithography apparatus according to claim 2, wherein the distance between the screw and the inner surface of the pipe is 2 mm or less, and the screw rotated by the rotating means moves the pipe. By applying shear stress to the additional slurry to the inner surface of the, the additional slurry stored in the slurry container is conveyed in the pipe while reducing the viscosity, and is supplied to the discharge means through the supply unit. It is characterized by

The invention of claim 4 is the stereolithography apparatus according to claim 2 or 3 , wherein the reservoir of the slurry container includes an inclined surface at an angle of 30 degrees or more and 70 degrees or less from a horizontal plane. and

The invention of claim 5 is the stereolithography apparatus according to any one of claims 2 to 4, wherein the slurries of the slurry container are moved along the inner surface of the slurry container within the slurry container. A slurry container scraper for scraping off the additional slurry adhering to the inner surface is further provided.

The invention of claim 6 is the stereolithography apparatus according to any one of claims 2 to 5 , wherein the slurry container is placed at a predetermined position on the upper end of the slurry container with the opening directed downward or obliquely downward. a replenishment container that can be placed in the slurry, the replenishment container holds new slurry, and is placed at the predetermined position with the opening facing downward or obliquely downward, The new slurry is supplied to the slurry container as the additional slurry.

The invention of claim 7 is the stereolithography apparatus of claim 6 , wherein the replenishment container moves along the inner surface of the replenishment container in the state where the replenishment container is placed at the predetermined position. a replenishment container scraper for scraping off the additional slurry adhering to the inner surface of the replenishment container.

The invention of claim 8 is the stereolithography apparatus according to claim 6 or 7 , wherein the replenishment container is rotatably fixed to the slurry container, and the opening is directed upward or obliquely upward. a hinge for rotating the replenishment container from the open position to the position in which the opening faces downward or obliquely downward.

The invention of claim 9 is the optical molding apparatus according to any one of claims 2 to 8 , further comprising a drain provided in the pipe, wherein the supply path from the slurry container to the pipe has The slurry remaining in the pipe can be discharged by releasing the drain with the lid closed and rotating the screw in a direction opposite to when the slurry is supplied.

The invention of claim 10 is the optical forming apparatus according to any one of claims 1 to 9 , wherein the scraper has a double annular main body, and the slurry is discharged inside the discharge means. It is characterized by homogenizing the viscosity .

According to the inventions of claims 1 to 10 , even when a large-sized or large-area modeled object is modeled, the supply of the modeling material is suitably ensured.

Incidentally, if the area of the pump scraper 43 is large, the resistance due to the slurry SL increases. On the other hand, it is desirable that the viscosity of the slurry SL in the slurry discharge pump 40 is as uniform as possible in order to keep the discharge speed highly constant. If the outer diameter of is greatly different from the inner diameter of the reservoir 40B, the uniformity of the viscosity of the slurry SL may be lost. This is because the softening of the slurry SL due to the shear stress of the pump scraper 43 extends only to a distance of several centimeters from the pump scraper 43 .

Claims (9)

A stereolithography apparatus for obtaining a three-dimensional object,
a molding table;
a discharge means capable of discharging slurry onto the modeling table;
sweeping means for sweeping the slurry discharged onto the modeling table to form a slurry film with a predetermined thickness;
exposure means for exposing the slurry film according to an exposure pattern prepared in advance based on three-dimensional shape data;
monitoring means for monitoring the remaining amount of the slurry in the discharging means during the production of the three-dimensional model;
replenishment means for replenishing additional slurry to the discharge means;
control means for causing the replenishing means to replenish the additional slurry to the discharging means at a predetermined timing when the remaining amount is less than a specified value based on the monitoring result of the monitoring means;
A stereolithographic apparatus, comprising: The stereolithography apparatus according to claim 1,
The supply means is
a pipe that is slanted from a horizontal plane;
a screw accommodated in the pipe without contacting the pipe;
rotating means for rotating the screw within the pipe;
a slurry container connected to an intermediate position of the pipe and storing the additional slurry;
a supply unit, which is a supply port for the additional slurry, connected to the upper end of the pipe;
with
By rotating the screw by the rotating means, the screw conveys the additional slurry stored in the slurry container within the pipe, and supplies it to the discharging means through the supply section.
An optical molding apparatus characterized by: The stereolithography apparatus according to claim 2,
The storage part of the slurry container includes an inclined surface at an angle of 30 degrees or more and 70 degrees or less from the horizontal plane,
An optical molding apparatus characterized by: The optical shaping apparatus according to claim 2 or 3,
a slurry container scraper that moves along the inner surface of the slurry container within the slurry container to scrape off the additional slurry adhering to the inner surface of the slurry container;
A stereolithographic apparatus, further comprising: The optical shaping apparatus according to any one of claims 2 to 4,
A replenishment container that can be placed at a predetermined position on the upper end of the slurry container with the opening directed downward or obliquely downward;
further comprising
The replenishment container holds new slurry and is placed at the predetermined position with the opening directed downward or obliquely downward, so that the new slurry is used as the additional slurry in the slurry container. supply to
An optical molding apparatus characterized by: The stereolithography apparatus according to claim 5,
The additional slurry adhering to the inner surface of the replenishing container is scraped off by moving the replenishing container along the inner surface of the replenishing container while the replenishing container is placed at the predetermined position. refill container scraper,
A stereolithographic apparatus, further comprising: The stereolithography apparatus according to claim 5 or claim 6,
a hinge that rotatably fixes the replenishment container to the slurry container and rotates the replenishment container from an orientation in which the opening faces upward or diagonally upward to an orientation in which the opening faces downward or obliquely downward;
A stereolithographic apparatus, further comprising: The optical shaping apparatus according to any one of claims 2 to 7,
a drain provided in said pipe;
further comprising
The slurry remaining in the pipe can be discharged by releasing the drain while the supply path from the slurry container to the pipe is covered and rotating the screw in the opposite direction to when the slurry is supplied. be,
An optical molding apparatus characterized by: The optical shaping apparatus according to any one of claims 1 to 8,
The discharge means is
a funnel-shaped discharge part tapered at the lower end;
a cylindrical storage part that is continuous with the upper part of the discharge part and in which the slurry is stored;
a discharge screw inserted from the storage part to the discharge part;
a driving motor for rotating the ejection screw;
with
The slurry is discharged from the discharge unit by rotating the discharge screw by the drive motor.
An optical molding apparatus characterized by:

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