STEREOLITHOGRAPHY DEVICE AND METHOD FOR MANUFACTURING A THREE-DIMENSIONAL OBJECT

Abstract

Stereolithography device (1) for producing a three-dimensional object, comprising: an exposure device (20) for exposing a photocurable material according to an exposure pattern generated in advance on the basis of three-dimensional shape data; and a control device (C) for controlling the operation of the stereolithography device (1), wherein the exposure device (20) comprises: a projector (21) comprising a plurality of pixels (PXL) in a two-dimensional array and adapted to individually switch ON-OFF states of exposure light at the respective pixels (PXL), wherein the projector (21) is movable in a second direction (y) orthogonal to a first direction (x) in a posture inclined with respect to the second direction (y), so that center positions of two adjacent pixels (PXL) of the plurality of pixels (PXL) are spaced from each other by a predetermined character pitch (Re) in the first direction (x), and is adapted to switch the ON-OFF states of the exposure light each time the projector (21) moves by a distance corresponding to the character pitch (Re) in the second direction (y), and the control device (C) causing the projector (21) to expose the light-curable material in a predetermined character area successively for a plurality of stripe areas (L) each extending in the second direction (y) and having a predetermined character width in the first direction (x) by individually switching the ON-OFF states of the exposure light at the respective pixels on the basis of the exposure pattern while alternating a forward movement and a backward movement in the second direction (y) with an intermediate step movement in the first direction (x), and in a case where a plurality of layers of the photocurable material are each exposed by the exposure device (20) while being stacked on top of one another to obtain the three-dimensional object, forming a connecting portion (JT) of two adjacent stripe regions (L) of the plurality of stripe regions (L) by overlapping the adjacent stripe regions (L) along the first direction (x) and causing an in-plane position of the connecting portion (JT) to differ between at least two layers of the plurality of layers.

Description

TECHNICAL FIELD

[0001] The present invention relates to a stereolithography apparatus and a method for producing a three-dimensional object. STATE OF THE ART

[0002] Additive manufacturing is a manufacturing process that offers the significant advantage of enabling the direct production of a complex three-dimensional object and is much more flexible than a conventional method for producing a three-dimensional workpiece using machining. Furthermore, its advantages have received considerable attention in recent years.

[0003] A process called "free liquid level" is widely known as an example of an additive manufacturing process and is achieved by a scanning exposure system with a laser beam and a galvanometer mirror. A backside exposure scheme called "regulated liquid level" is also known, in which exposure and suspension are alternated for fabrication, such that a layer of an object is fabricated by collective exposure using a DMD (Digital Micromirror Device) through glass from one side of a bottom surface of a container containing a light-curable material, and then a space under the object is filled with the material to a required thickness while the object is suspended (see, for example, JP 2017-124631 A).

[0004] However, in recent years, a method has become established for three-dimensional stereolithography in which a light-curable resin is applied to a flat surface and the resin is exposed from above by laser scanning. For example, a method is known in which a pasty material, a so-called slurry, obtained by kneading a mixture of a light-curable monomer resin (liquid) and ceramic powder, is alternately spread onto a production table, and a required area is exposed from above by laser scanning to cure the resin, thus obtaining a three-dimensional object (see, for example, JP 6 438 919 B2).

[0005] A method for performing high-speed exposure (drawing) by a scheme of supplying an exposure pattern while moving a DMD projector, for example, in a row direction of a mirror array (a matrix), is also known. However, this scheme is not necessarily suitable for high-resolution drawing because a projected pixel size in the row direction represents a minimum character unit. In view of the above, as a scheme achieved by improving the exposure scheme, a scheme in which a DMD mirror is tilted with respect to a moving direction to enable a finer minimum character unit for exposure is already known (see, for example, JP 3 938 714 B2).

[0006] Further prior art documents are US 2020 / 0 353 685 A1, US 2019 / 0 022 941 A1, US 2017 / 0 015 058 A1, EP 3 487 704 B1 and DE 601 27 512 T2. SUMMARY OF THE PROBLEM TO BE SOLVED BY THE INVENTION

[0007] There is a growing need to increase the size and surface area of ​​an object as the advantages of three-dimensional stereolithography are increasingly recognized. The increase in object size leads to an increase in the time required for the manufacturing process, so any measures to increase the efficiency of the manufacturing process are naturally aimed at improving productivity.

[0008] In addition, it is necessary to stabilize the exposure accuracy during manufacturing when manufacturing an object with a large size or a large area.

[0009] The present invention was made in view of the above-mentioned problem, and it is an object of the present invention to provide a stereolithography apparatus that ensures adequate exposure accuracy even when an object has a larger size. A corresponding method is also to be provided. This object is achieved by the subject matter of independent claims 1, 5, and 6. Preferred embodiments and further developments are the subject matter of the dependent claims. The invention is defined by the claims, with aspects of the invention being set forth below.

[0010] In order to solve the above-mentioned problem, a first aspect of the present invention is a stereolithography apparatus for manufacturing a three-dimensional object, comprising: exposure means for exposing a photocurable material according to an exposure pattern generated in advance based on three-dimensional shape data; and control means for controlling the operation of the Stereolithography device, wherein the exposure device comprises: a projector comprising a plurality of pixels in a two-dimensional array and adapted to individually switch ON-OFF states of exposure light at the respective pixels, wherein the projector is movable in a second direction orthogonal to a first direction in a posture inclined with respect to the second direction such that center positions of two adjacent pixels of the plurality of pixels are spaced from each other by a predetermined character pitch in the first direction, and is adapted to switch the ON-OFF states of the exposure light each time the projector moves a distance corresponding to the character pitch in the second direction, and the control device causes the projector to expose the photocurable material in a predetermined character area sequentially for a plurality of stripe areas,each extending in the second direction and having a predetermined character width in the first direction, by individually switching the ON-OFF states of the exposure light at the respective pixels based on the exposure pattern while alternating a forward movement and a backward movement in the second direction with an intermediate step movement in the first direction, and in a case where a plurality of layers of the photocurable material are each exposed by the exposure device while being stacked on top of each other to obtain the three-dimensional object, forming a connecting portion of two adjacent stripe regions of the plurality of stripe regions and causing an in-plane position of the connecting portion to differ between at least two layers of the plurality of layers.

[0011] A second aspect of the present invention is the stereolithography apparatus according to the first aspect, wherein, in a case where the plurality of layers of the photocurable material are respectively exposed by the exposure means while being stacked on each other to obtain the three-dimensional object, the control means causes the in-plane position of the connecting portion to be different between the plurality of layers.

[0012] A third aspect of the present invention is the stereolithography apparatus according to the second aspect, wherein the in-plane position of the connecting portion when the projector exposes each of the plurality of layers is shifted by an integer multiple of L / N in the first direction from the in-plane position of the connecting portion in a layer which is exposed first among the plurality of layers,

[0013] A fourth aspect of the present invention is the stereolithography apparatus according to any one of the first to third aspects, further comprising: a fabrication table; a dispensing means adapted to dispense a slurry as a photocurable material onto the fabrication table; and a scraping means for scraping the slurry dispensed onto the fabrication table to form a slurry film having a predetermined thickness, wherein the control means repeats the dispensing of the slurry by the dispensing means and the scraping of the dispensed slurry by the scraping means to stack a plurality of slurry films as the plurality of layers.

[0014] A fifth aspect of the present invention is a stereolithography apparatus for manufacturing a three-dimensional object, comprising: a production table; an exposure device for exposing a photocurable material according to an exposure pattern generated in advance based on three-dimensional shape data; and a dispensing device adapted to dispense a slurry as the photocurable material onto the production table; and a scraping device for scraping the slurry discharged onto the production table to form a slurry film having a predetermined thickness, wherein a control device for controlling the operation of the stereolithography apparatus, wherein the exposure device comprises: a projector including a plurality of pixels in a two-dimensional array and adapted to individually switch ON-OFF states of exposure light at the respective pixels,wherein the projector is movable in a second direction orthogonal to a first direction in an inclined posture with respect to the second direction such that center positions of two adjacent pixels of the plurality of pixels are spaced apart from each other by a predetermined character pitch in the first direction, and is adapted to switch the ON-OFF states of the exposure light each time the projector moves a distance corresponding to the character pitch in the second direction, and the control device causes the projector to expose the light-curable material in a predetermined drawing area sequentially for a plurality of stripe areas each extending in the second direction and having a predetermined character width in the first direction by individually switching the ON-OFF states of the exposure light at the respective pixels based on the exposure pattern,while a forward movement and a backward movement in the second direction are alternated with an intermediate step movement in the first direction, and in a case where a plurality of layers of the photocurable material are respectively exposed by the exposure device while being stacked on one another to obtain the three-dimensional object, the dispensing of the slurry by the dispensing device and the scraping of the dispensed slurry by the scraping device are repeated to stack a plurality of slurry films as the plurality of layers, and forms a connecting portion of two adjacent stripe regions of the plurality of stripe regions when the plurality of slurry films are respectively formed, at least the dispensing device and the scraping device are controlled so that each of the slurry films has not only a first region,but also comprises a second region and a third region, wherein the first region is a region in which the application of the slurry is originally required for the production of the three-dimensional object, the second region is a region that is closer to a wiper start position than the first region in a predetermined range, and the third region is a region between the first region and the second region, causes the position of the center of gravity in a horizontal plane of each of the slurry films to be substantially the same as or close to the position of the center of gravity in a horizontal plane of the production table, causes the exposure device to expose the second region when the first region is exposed according to the exposure pattern, and causes, when an m-th layer of the plurality of slurry films is formed,the dispensing device dispenses the slurry onto the second region of an (m-1) layer of the slurry films, where m is an integer equal to or greater than two.,

[0015] A sixth aspect of the present invention is a method for manufacturing a three-dimensional object, comprising: an exposure step of exposing a photocurable material according to an exposure pattern generated in advance based on three-dimensional shape data using a projector including a plurality of pixels in a two-dimensional array and adapted to individually switch ON-OFF states of exposure light at the respective pixels, wherein in the exposure step, the projector is caused to expose in a posture inclined with respect to a second direction orthogonal to a first direction such that center positions of two adjacent pixels of the plurality of pixels are spaced from each other by a predetermined pitch in the first direction,the light-curable material is exposed in a predetermined drawing area successively for a plurality of stripe areas each extending in the second direction and having a predetermined character width in the first direction by switching the ON-OFF states of the exposure light at the respective pixels individually on the basis of the exposure pattern each time the projector moves a distance corresponding to the character pitch in the second direction while alternating a forward movement and a backward movement in the second direction with an intermediate step movement in the first direction, and in a case where a plurality of layers of the light-curable material are each exposed in the exposure step while being stacked on top of each other to obtain the three-dimensional object,a connecting portion is formed by two adjacent strip regions of the plurality of strip regions and an in-plane position of the connecting portion is caused to differ between at least two layers of the plurality of layers., EFFECTS OF THE INVENTION

[0016] According to the first to sixth aspects of the present invention, an influence of the presence of the connecting portion on the manufacturing accuracy can be appropriately reduced, and an object with high dimensional accuracy can be obtained.

[0017] According to the fifth aspect, the application of a bias voltage to the fabrication table is appropriately reduced even in a case where the object has a large weight, and the reduction in fabrication accuracy (exposure accuracy) caused by the bias voltage is appropriately suppressed. Furthermore, in a case where the object has a small planar size, a slurry film of a required size can be formed using a slurry dispensed in a minimum required dispensing amount, while appropriately reducing the application of the bias voltage to the fabrication table. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing a schematic configuration of a stereolithography apparatus 1. Fig. 2 is a functional block diagram of a portion of the stereolithography apparatus 1. Fig. 3 is a side view showing an arrangement relationship between main components of the stereolithography apparatus 1. Fig. 4 is a flowchart showing a series of operations of the stereolithography apparatus 1. Fig. 5 is a flowchart showing a series of operations of the stereolithography apparatus 1. Fig. 6 is a flowchart showing a series of operations of the stereolithography apparatus 1. Fig. 7 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 8 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 9 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 10 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 11 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 12 is a side view schematically showing the stereolithography apparatus 1 in the process. Fig. 13 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 14 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 15 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 16 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 17 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 18 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 19 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 20 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 21 is a side view schematically showing the stereolithography apparatus 1 during the manufacturing process. Fig. 22 is a schematic representation of the inclined exposure by the projectors 21 of the stereolithography device 1. Fig. Fig. 23 is a diagram for explaining a pixel arrangement and an inclination of a projector 21. Fig. 24 is a diagram for explaining the pixel arrangement and inclination of the projector 21. Fig. 25 is a diagram illustrating the change of an exposure pattern when a character area DA is exposed for each character width L according to a predetermined character pattern while the projector 21 moves. Fig. Fig. 26 is a diagram for explaining the exposure by which the effect of connecting portions can be avoided. Fig. 27A to 27C are diagrams for explaining the exposure by which the effect of connecting sections can be avoided. Fig. 28 is a side view schematically showing the stereolithography apparatus 1 during manufacturing in a case where the slurry discharge portion is formed simultaneously. Fig. 29 is a side view schematically showing the stereolithography apparatus 1 during manufacturing in a case where the slurry discharge portion is formed simultaneously. Fig. 30 is a side view schematically showing the stereolithography apparatus 1 during manufacturing in a case where the slurry discharge portion is formed simultaneously. Fig. 31 is a side view schematically showing the stereolithography apparatus 1 during manufacturing in a case where the slurry discharge portion is formed simultaneously. Fig. 32 is a side view showing manufacturing in a case where an object has a small planar size relative to a manufacturing table 11. Fig. Figure 33 is an overview diagram of an apparatus that forms a three-dimensional object by a free liquid level process. DESCRIPTION OF EMBODIMENTS

[0018] A laser scanning scheme used in the free liquid level method is an exposure scheme advantageous for high-resolution drawing because it enables the reduction of the exposure spot diameter to a fine diameter and the control of a spot position on a drawing surface in the micrometer range. However, in a laser scanning exposure scheme, the exposure is essentially a scanning exposure at a point of laser light, in which an outline and filled areas are sequentially exposed by the laser light as a continuous line. The exposure time per drawing area is thus essentially proportional to the drawing area. For example, drawing a 20 square centimeter area with laser light with a beam diameter of 30 μm requires an exposure time of several tens of minutes intervals per area (layer).

[0019] In contrast, the exposure time per area in collective exposure using DMD projector projection, as used in the controlled liquid level method, is in principle extremely short, although it depends on the energy level. In the case of the DMD collective exposure scheme, the reduced projection using an optical system enables exposure to a fine pixel in the micrometer range, but extremely narrows the drawing area in a single exposure, requiring step-by-step exposure with repetition, which greatly reduces manufacturing productivity. Therefore, it is typical to compensate for productivity by projection exposure with a pixel size of 50 µm and the like. The pixel size inevitably becomes a minimum drawing unit.Sequential exposure using step & repeat is of course carried out in a similar way when exposing a large area, so the exposure time for fine drawing also increases with this scheme.

[0020] An exposure scheme as disclosed in JP 3 938 714 B2 has been used in an apparatus that exposes only one surface, for example, in the exposure of a printed circuit board. When exposing the printed circuit board, a large area of, for example, 500 square millimeters must be drawn with high resolution in the micrometer range, so this exposure scheme typically uses reciprocal drawing. That is, the DMD projector alternately exposes forward and backward (unit exposure) with a predetermined width, while being shifted a predetermined distance in a direction perpendicular to an exposure direction each time a movement is completed, thereby exposing a target area as a whole.

[0021] In this case, the exposure state of a connecting portion of adjacent unit exposure areas differs from that of other portions in the narrow sense. This rarely causes significant problems when exposing a single surface, such as the circuit board. However, when applying the exposure scheme described above for additive manufacturing, exposure is essentially performed not only for one area, but each time several tens of slurry films or hundreds or more slurry films are successively stacked.

[0022] JP 6 438 919 B2 discloses a scheme in which a liftable application fixture (auxiliary table) is provided at one side of a production table, a light-curable material is applied to the application fixture, and then the material is transferred by wiping with a doctor blade on the production table to obtain an object that is large in a height direction. In this case, the position of the application fixture is essentially limited to a position on one side of the production table, so the object is typically formed at one end of the production table near the application fixture. <Device Overview>

[0023] Fig. 1 is a perspective view showing a schematic configuration of a stereolithography apparatus 1 according to the present embodiment. Fig. 2 is a functional block diagram of a portion of the stereolithography apparatus 1. Fig. 3 is a side view showing an arrangement relationship between main components of the stereolithography apparatus 1.

[0024] The stereolithography apparatus 1 according to the present embodiment is essentially an apparatus that applies a pasty material called slurry, obtained by kneading a mixture of a photocurable monomer resin (liquid) and ceramic powder (e.g., alumina), to a fabrication table. For each of the successively layered slurry films (layers), the resulting slurry film is irradiated with light from a laser, an LED, and the like from above to expose a required area for curing the resin, thereby obtaining a three-dimensional object (layered object). The exposure based on exposure pattern data performed by the stereolithography apparatus 1 is also referred to as drawing.

[0025] The stereolithography apparatus 1 essentially comprises a manufacturing table 11, an auxiliary table 12, an exposure unit 20, a coating unit 30, a slurry discharge pump 40 and a controller C ( Fig. 2). Fig. 1 is provided with right-handed xyz coordinates, where a direction from the auxiliary table 12 to the production table 11 is indicated as the positive y-axis direction and a vertically upward direction is indicated as the positive z-axis direction (a similar coordinate system is used in the subsequent figures).

[0026] The production table 11 is a rectangular table in plan view with an upper surface on which production is carried out. The production table 11 can be lifted in the z-axis direction, as indicated by an arrow AR1. The lifting operation is carried out by a z-axis lifting mechanism 11M ( Fig. 2). Specifically, the production table 11 is provided as shown in Fig. 3, essentially moves between a starting position 11a (height h1), a dispensing / exposure position 11b (height h2) and a coating position 11c (height h3).

[0027] The production table 11 is essentially raised from the starting position 11a during application of the slurry and subsequent exposure and lowered by a required amount with each progressive shaping of an object (each time the shaping for a respective layer is completed).

[0028] The manufacturing table 11 preferably has a manufacturing area of ​​at least 600 mm × 600 mm or more, and more preferably a manufacturing area of ​​at least 650 mm × 650 mm or more, in order to enable the manufacturing of an object with large dimensions.

[0029] The production table 11 has a plurality of suction grooves (grooves) 11g in its upper surface. The plurality of suction grooves 11g are used when attaching or fixing a film (e.g., a protective film) placed on the upper surface of the production table 11 during production. The plurality of suction grooves 11g are provided on the entire production surface. In particular, the plurality of suction grooves 11g are connected to an air suction / exhaust mechanism 11AR ( Fig. 2), and the air suction / blowout mechanism 11AR applies negative pressure to the plurality of suction grooves 11g while the film is placed thereon to vacuum-suck the film under the control of the controller C (an example of a control device of the present disclosure).

[0030] For transport after completion of the object, the suction is released under the control of the controller C, and air is supplied to the suction grooves 11g instead from the air suction / exhaust mechanism 11AR. The object, together with the film, is thereby lifted slightly from the production table 11, making it easier to hold the film with a film gripper 52, described below, and to transport the film together with the object on the film.

[0031] The auxiliary table 12 is a rectangular table in plan view, which serves for preparing the film and for transporting the finished object. The auxiliary table 12 has essentially the same surface dimensions as the production table 11. The auxiliary table 12 is held and supported by a mounting section (support) 12F and is located, as shown in Fig. 3, at the same height h1 as the home position 11a of the production table 11. The auxiliary table 12, together with the attachment portion 12F, is retractable in the y-axis direction, as indicated by an arrow AR2. Specifically, the auxiliary table 12 is moved back and forth between a normal position 12a and an adjacent position 12b in which it is adjacent to and flush with the production table 11 located in the home position 11a on one side in the positive y-axis direction. The movement operation is performed by a y-axis movement mechanism 12M ( Fig. 2) of the mounting portion 12F. The y-axis movement mechanism 12M includes an actuator.

[0032] The auxiliary table 12 also has a plurality of suction grooves (grooves) 12g in its upper surface. The plurality of suction grooves 12g are used when the film, which is placed on the upper surface of the production table 11 during production, is first fixed before being placed. In particular, the plurality of suction grooves 12g are connected to the air suction / blowing mechanism 11AR ( Fig. 2), and the air suction / exhaustion mechanism 11AR applies negative pressure to the plurality of suction grooves 12g while the film is placed thereon to suck the film by vacuum. The film placed on the auxiliary table 12 is transported to the production table 11 by a suction gripper unit 51, which will be described below.

[0033] Furthermore, the auxiliary stage 12 is detachable from the mounting portion 12F in the normal position 12a. That is, the auxiliary stage 12 is portable and can be transported separately from the y-axis moving mechanism 12M and the air intake / exhaust mechanism 11AR. The stereolithography apparatus 1 according to the present embodiment can transport the object, which has been transported to the auxiliary stage 12 after completion, together with the auxiliary stage 12, utilizing the portability of the auxiliary stage 12.

[0034] The air intake / exhaust mechanism 11AR comprises, for example, Fig. 3, a vacuum pump (an example of a suction device of the present disclosure) PP1, an air pressure pump (an example of an air supply device of the present disclosure) PP2, and switching valves VLV1 and VLV2. The switching valve VLV1 and the switching valve VLV2 operate as switching devices that switch between suction by the vacuum pump PP1 and air discharge by the air pressure pump PP2 on the production table 11 and the auxiliary table 12, respectively. The controller C controls the vacuum pump PP1, the air pressure pump PP2, and the switching valves VLV1 and VLV2 to switch between applying negative pressure and lifting the film by air.

[0035] The plurality of suction grooves 11g are provided in such a way that they are distributed among a plurality of independent zones zn, and the switching valves VLV1 and VLV2 switch between suction by the vacuum pump PP1 and blowing by the compressed air pump PP2 for each of the zones zn. The suction grooves 11g in the zones zn are selectively used depending on the size and position of the object to be transported. While the rectangular suction grooves 11g and 12g in Fig. 1 are arranged two-dimensionally, these arrangements are merely examples, and the plurality of suction grooves 11g and 12g may also be present in other arrangements, e.g., in stripes.

[0036] The exposure unit (an example of an exposure device) 20 is a light source including one or more projectors 21, each of which emits light. Each of the projectors 21 has a light-emitting element, such as a laser and an LED. The exposure unit 20 is movable forward and backward in the y-axis direction, as indicated by an arrow AR3. The movement is controlled by a pair of left and right linear motors 20M ( Fig. 2) provided in Fig. 1 are not shown.

[0037] The projector 21 is a member that performs pattern exposure (projection) of a coated slurry film formed above the production table 11. The projector 21 performs exposure using, for example, a DMD projection scheme. That is, a projection pattern (data) is input while the projector 21 is moved stepwise or continuously in the y-axis direction to project the pattern. The projector 21, after completing the movement in one direction, is moved a predetermined distance in the x-axis direction and performs exposure again while moving in the opposite direction of the y-axis. That is, in the present embodiment, exposure is performed strip by strip for each area with a predetermined width. The above-described process is repeated until exposure is completed for the entire target area to be produced in each layer.

[0038] In particular, the projector 21 is arranged such that it is slightly tilted with respect to the y-axis direction and is moved in this tilted posture. Therefore, a scheme used by the stereolithography apparatus 1 according to the present embodiment is also referred to as an inclined exposure scheme. The inclined exposure scheme will be described in more detail below.

[0039] The projector 21 is arranged such that its lower end is at a height spaced upward along the z-axis from the delivery / exposure position 11b of the production table 11 by a predetermined projector operating distance (Proj_WD).

[0040] The Fig. The stereolithography apparatus 1 shown in Fig. 1 comprises four projectors 21 (21a to 21d) arranged at regular intervals in the x-axis direction, and the four projectors 21 perform exposure synchronously with each other.

[0041] The movement of the projectors 21 in the y-axis direction is achieved by the movement of the exposure unit 20 as a whole. On the other hand, the movement in the x-axis direction, indicated by an arrow AR4, is provided by an x-axis movement mechanism 21M ( Fig. 2). The x-axis movement mechanism 21M includes an actuator.

[0042] The coating unit 30 is a complete unit comprising a coater (an example of a scraper device of the present disclosure) 31, the slurry discharge pump (an example of a discharge device of the present disclosure) 40, and a screw 42. The coating unit 30 is movable forward and backward in the y-axis direction, as indicated by an arrow AR6. The movement is controlled by a pair of left and right linear motors 30M ( Fig. 2) provided in Fig. 1 are not shown. Guide rails for the linear motors 30M are preferably used together with the linear motors 20M to move the exposure unit 20.

[0043] The coater 31 is a doctor blade-like member that scrapes and applies the slurry applied to the production table 11. The coater 31 is attached to the coating unit 30 with a longitudinal direction extending in the x-axis direction and has substantially the same size as the production table 11 in the x-axis direction. The coater 31 moves in the y-axis direction due to the movement of the coating unit 30 while maintaining a predetermined distance from the production table 11, and spreads the slurry applied to the production table 11 in the y-axis direction to form a slurry film.

[0044] The coater 31 is cleaned after use by a cleaning unit (cleaner) 32. The cleaning unit 32 is arranged at a position below one end of the coater 31 to be lifted or moved between a working height 32a, a production standby height 32b, and a standby height 32c, as indicated by an arrow AR7. Furthermore, the cleaning unit 32 is movable in the x-axis direction at the working height 32a, as indicated by an arrow AR8. The cleaning unit 32 may include a spatula, a brush, or the like, or may have a different configuration.

[0045] After use of the coater 31, the cleaning unit 32 disposed at the insertion height 32a moves in the x-axis direction while in contact with the coater 31 to remove any slurry adhering to (remaining on) the coater 31. In this way, the coater 31 is cleaned.

[0046] If the application of the slurry is subsequently repeated, the cleaning unit 32 waits at the production standby height 32b. After all applications have been completed, the cleaning unit 32 waits at the standby height 32c until further use.

[0047] The movement of the cleaning unit 32 in the direction of the z-axis indicated by the arrow AR7 is carried out by a z-axis lifting mechanism 32M1 ( Fig. 2). The movement of the cleaning unit 32 in the x-axis direction indicated by the arrow AR8 is carried out by an x-axis movement mechanism 32M2 ( Fig. 2). The x-axis movement mechanism 32M2 includes an actuator.

[0048] The slurry discharge pump 40 is a pump that has the function of storing a slurry for production therein and discharging the slurry onto the production table 11 during production. The slurry discharge pump 40 is movable not only in the y-axis direction due to the movement of the coating unit 30, but also, as indicated by an arrow AR9, in the x-axis direction by an x-axis moving mechanism 40M ( Fig. 2) Movable. The x-axis movement mechanism 40M includes an actuator.

[0049] The slurry discharge screw 42 is attached to the slurry discharge pump 40. The screw 42 is rotated by a screw drive motor 42M. The screw 42 rotates within the slurry discharge pump 40 to discharge the slurry from a lower end of the slurry discharge pump 40. The amount of slurry discharged from the slurry discharge pump 40 depends on the rotation speed of the screw 42. The discharge height h4, the distance between the lower end of the slurry discharge pump 40 and the discharge / exposure position 11b of the production table 11, is appropriately adjusted, taking into account the slurry material and the like.

[0050] The stereolithography apparatus 1 further includes the suction gripper unit (a suction carrier) 51 as an example of a suction transport device of the present disclosure and the film gripper 52 as an example of a holding transport device of the present disclosure as components responsible for the movement of the film.

[0051] The suction gripper unit 51 is a film suction mechanism that sucks the film resting on the auxiliary table 12 and transfers the sucked film to the production table 11. The suction gripper unit 51 normally remains in a standby position 51a ( Fig. 3) set below a standby position of the exposure unit 20, and is attached to the bottom of the exposure unit 20 by means of a pin fastener (not shown) when the exposure unit 20 is in operation and controlled by the controller C. The suction pad unit 51 moves in the negative y-axis direction together with the exposure unit 20 and sucks one end of the film in the positive y-axis direction on the auxiliary table 12 at a suction position 51b located above one end of the auxiliary table 12 in the positive y-axis direction after the auxiliary table 12 has been moved to the adjacent position 12b. The exposure unit 20 moves in the positive y-axis direction while maintaining the suction state, so that the suction pad unit 51 moves to an end position 51c to transport or transfer the film to the production table 11.

[0052] The suction and release of the film is achieved, as indicated by an arrow AR5, by the up and down movement of the suction gripper unit 51. The up and down movement is provided by an air cylinder 51AS. The air for driving is supplied via a common connection (not shown) in the exposure unit 20.

[0053] The film gripper 52 is formed by a pair of film holding mechanisms used when the finished object is transported or transferred from the production table 11 to the auxiliary table 12. The film gripper 52 normally stays in a standby position 52a ( Fig. 3) set below a standby position of the coating unit 30 at opposite ends of the auxiliary table 12 in the x-axis direction, and is attached to the bottom of the coating unit 30 by means of a pin fastener (not shown) when the coating unit 30 is in operation and controlled by the controller C. The film gripper 52 moves in the positive y-axis direction together with the coating unit 30 and holds the opposite ends of the film, which is floated or raised together with the object, at a holding position 52b set at the opposite ends in the negative y-axis direction of the production table 11. The coating unit 30 moves in the negative y-axis direction while maintaining the holding state, so that the film and the object mounted on its upper surface are transported to the auxiliary table 12.In this case, the zones zn, to which the suction grooves 11g and 12g supplied with air by the compressed air pump PP2 are assigned, are switched sequentially according to the movement of the object. This means that only the suction grooves 11g and 12g required for levitating and lifting the moving object using the air flow, respectively, are used sequentially and selectively.

[0054] During transport of the object, the air supply from the suction grooves 11g and 12g not directly beneath the film or the suction grooves 11g and 12g not directly beneath the object can be interrupted. This prevents or reduces the discharge of a large amount of air from the less loaded suction grooves 11g and 12g, above which there is no film or object, and allows a sufficient amount of air to be discharged from the suction grooves 11g and 12g located directly beneath the object and required for levitating or lifting the object. The controller C can determine an area to which air is supplied depending on a transport distance of the film, or detect a position of the film and / or a position of the object using a sensor and determine an area to which air is supplied depending on a detection result.

[0055] The stereolithography apparatus 1 further includes a fan filter unit (FFU) 15 and the like. The FFU 15 is a mechanism for maintaining cleanliness within the stereolithography apparatus 1.

[0056] The operation of the individual components of the stereolithography device 1 with the configuration described above is controlled by the control C ( Fig. 2). Control C can be implemented by a universal or special-purpose computer.

[0057] The controller C preferably includes a manufacturing data processing unit C1 that converts three-dimensional shape data (CAD data) of an object into projection (exposure) pattern data that can be used for strip-by-strip exposure of each layer by the projector 21. The section data generated by the manufacturing data processing unit C1 are used sequentially by the projector 21 for pattern exposure.

[0058] The manufacturing data processing unit C1 can be provided as a separate or independent computer from the controller C. <Betrieb der Stereolithographievorrichtung>

[0059] The Fig. 4 to 6 are flowcharts showing a series of operations of the stereolithography apparatus 1 when the stereolithography apparatus 1 forms the object. Fig. 7 to 21 are side views each schematically showing the stereolithography apparatus 1 during the manufacturing process.

[0060] First, each component and unit is moved to its home position (ready position) (step S1). Specifically, the production table 11, the auxiliary table 12, the exposure unit 20, and the coating unit 30 are arranged in the home positions.

[0061] As in Fig. As shown in Figure 7, an operator manually places (loads) a film F (a protective film or simply referred to as a film) onto the auxiliary table 12 (step S2). The film F is placed so that it covers the entire surface of the auxiliary table 12. The air suction / exhaust mechanism 11AR exerts a negative pressure on the plurality of suction grooves 12g, so that the placed film F is sucked onto the auxiliary table 12. The auxiliary table 12 on which the film F is placed is moved as shown in Fig. 8, moving from the normal position 12a to the adjacent position 12b.

[0062] When the film F is ready, the suction gripper unit 51 is attached to the exposure unit 20 by means of the pin fastener (step S3). In this case, the air cylinder 51AS is supplied with air from the exposure unit 20 via a common connection.

[0063] Subsequently, the exposure unit 20 moves in the negative y-axis direction, so that the suction gripper unit 51 moves to the suction position 51b (step S4). The suction gripper unit 51 is lowered by the drive of the air cylinder AS and sucks the film F, as shown in Fig. 9 (step S5). During the suction process, the negative pressure exerted on the film F on the auxiliary table 12 is released.

[0064] The exposure unit 20 moves in the direction of the positive y-axis, whereby the suction gripper unit 51 sucks the film F (step S6). The film F is thus, as in Fig. 10, transported to the production table 11. The exposure unit 20 stops at a time when the suction gripper unit 51 has moved to the end position 51c and the film F covers the production table 11 as a whole.

[0065] Simultaneously with the stop, the air suction / discharge mechanism 11AR applies negative pressure to the plurality of suction grooves 11g, so that the film F is sucked onto the production table 11 (step S7). On the other hand, the suction by the suction pad unit 51 is released (step S8).

[0066] Subsequently, the exposure unit 20 is moved to the standby position, and the pin fastening is released to separate the suction pad unit 51 from the exposure unit 20 (step S9). In addition, as shown in Fig. 11, the auxiliary table 12 is moved from the adjacent position 12b to the normal position 12a (step S10). Alternatively, the operator can also place the film F directly onto the production table 11.

[0067] Next, the manufacturing data processing unit C1 generates stripe data from the three-dimensional shape data (CAD data) of the object to be manufactured (step S11) and further generates the projection (exposure) pattern data based on the stripe data (step S12). The stripe data is partial data of the three-dimensional shape data corresponding to an area in which the projector 21 performs exposure by moving in the y-axis direction.

[0068] The generated projection (exposure) pattern data is transmitted to the projector 21 (step S13). The slurry application occurs in parallel with the transmission (NO in step S14).

[0069] In particular, the movement of the auxiliary table 12 into the normal position 12a (step S10) is followed by a lifting of the production table 11, to which the film F is sucked and fixed in the dispensing / exposure position 11b at the height h2 (step S15).

[0070] Subsequently, the coating unit 30 moves in the positive y-axis direction, so that the slurry discharge pump 40 is moved to a predetermined slurry discharge position. The slurry discharge position can be adjusted depending on the size and area of ​​the object to be manufactured and is located, as shown in Fig. 12, generally on the side of the production table 11 facing away from the y-axis direction. In the slurry discharge position, the screw 42 is rotated at the required speed while the slurry discharge pump 40 moves in the x-axis direction with a discharge opening 44 opened at the lower end thereof, so that a predetermined amount of slurry is discharged in the form of a line onto the production table 11 (step S16).

[0071] Not only a single dispensing start point and a single dispensing end point pair, but also a plurality of dispensing start points and end points pairs can be set at appropriate intervals Δp in the y-axis direction. Such slurry dispensing is called multi-line dispensing. The dispensing operation is performed until the entire required amount of slurry is dispensed (step S17). In multi-line dispensing, the distance between the lower end of the slurry dispensing pump 40 and the lower end of the coater 31 is adjusted so that the front end of the coater 31 does not come into contact with the dispensed slurry.

[0072] After the slurry discharge is completed (YES in step S17), the discharge port 44 is closed by a shutter and the like, and then the coating unit 30 moves to a coating start position (step S18). After the coating unit 30 moves, the production table 11 is raised from the discharge / exposure position 11b to the coating position 11c (step S19). In this case, the distance between the coating position 11c and the lower end of the coater 31 corresponds to an application height h5 corresponding to the thickness of the slurry film SLF to be formed. The coating start position is typically set so that the coater 31 is located on a side farther away from the slurry discharge area in the positive y direction.

[0073] When the production table 11 reaches the coating position 11c, the coating unit 30 moves in the negative y-axis direction. The slurry discharged onto the production table 11 is thus scraped off by the coater 31, and the slurry film SLF with a predetermined thickness is formed, as shown in Fig. 13 (step S20).

[0074] When the coater 31 moves a predetermined distance in the y-axis direction to form the slurry film SLF in a predetermined area of ​​the production table 11, the coating unit 30 further moves in the negative y-axis direction and returns to the standby position (a coater cleaning position) (step S21, NO in step S22).

[0075] When the coating unit 30 reaches the standby position (coater cleaning position) (YES in step S22), the cleaning unit 32, which has been waiting at the standby height 32c until then, is moved as shown in Fig. 14 (step S23), the cleaning unit 32 is raised to a cleaning position (the use height 32a). The cleaning unit 32 performs a reciprocating movement in the x-axis direction to scrape off the slurry adhering to the coater 31 (step S24). Thus, the coater 31 is cleaned.

[0076] After completion of the cleaning, the cleaning unit 32 is retracted to an initial position in the x-axis direction (step S25) and further retracted to the production standby height 32b (step S26).

[0077] On the other hand, after the coating unit 30 moves to the cleaning position after completion of the formation of the slurry film SLF by the coater 31 (YES in step S22), the pattern exposure by the projector 21 proceeds in parallel with the cleaning of the coater 31.

[0078] Specifically, the production table 11 on which the slurry film SLF is formed is first moved from the coating position 11c to the dispensing / exposure position 11b (step S28). Finally, the exposure unit 20 is moved to an exposure start position (step S29). More specifically, the exposure unit 20 is moved in the negative y-axis direction, and the position of the projector 21 is adjusted in the x-axis direction.

[0079] When the projector 21 is arranged at a predetermined exposure start position, the slurry film SLF is formed as shown in Fig. 15, by a 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 on the basis of the exposure pattern data transmitted in advance, the exposure light EL emitted from the projector 21 in stripe units is exposed (step S30).

[0080] Specifically, in a case where a target stripe for exposure (one drawing) still remains at a time point when exposure for one stripe is completed by moving the exposure unit 20 in the y-axis direction (NO in step S31), the generation of stripe data (step S11), the generation of exposure pattern data (step S12), and the transmission of exposure pattern data (steps S13 and S14) intended for a next stripe are performed. Subsequently, the projector 21 performs a stepwise movement in the x-axis direction, and the exposure unit 20 moves in the y-axis direction opposite to a direction of the previous drawing to perform exposure based on the newly generated exposure pattern data.

[0081] After the drawing of all stripes is completed (YES in step S31), the exposure unit 20 is retracted to the standby position (step S32). In this case, the projector 21 also moves to the home position. At a time when the drawing of all stripes is completed, the cleaning of the coater 31 (step S24) is usually completed, and the cleaning unit 32 has moved to the production standby height 32b (YES in step S27).

[0082] In a case where it is necessary to subsequently perform drawing for another layer (the slurry film SLF) (NO in step S33), the process in and after step S11 is repeated. That is, the formation of the slurry film SLF and the exposure of the pattern are repeated. In this case, the slurry film SLF subjected to the last exposure is formed. Fig. Figure 16 shows the finished object (a laminated body LB of slurry films SLF) after all layers have been exposed, embedded in an unexposed part.

[0083] After completion of the object (YES in step S33), the production table 11 is moved as shown in Fig. 17, is lowered to the home position 11a to remove the unexposed part and remove the object (step S34). Furthermore, the cleaning unit 32, which was previously located at the production standby height 32b, is lowered to the standby height 32c (step S35).

[0084] Furthermore, the film gripper 52, located in the standby position 52a, is attached to the coating unit 30 by means of the pin fastener (step S36). Subsequently, the coating unit 30 moves in the positive y-axis direction to position the film gripper 52 in the holding position 52b at the opposite ends of the production table 11 in the negative y-axis direction (step S37). The film gripper 52 holds the ends of the film F, which lies under the object on the production table 11, in position (step S38).

[0085] On the other hand, the auxiliary table 12, which remains in the normal position 12a, is moved to the adjacent position 12b in parallel for holding (step S39). The production table 11, on which the object and the film F are mounted, and the auxiliary table 12 are thus flush with each other. In this state, the (vacuum) suction of the film F onto the production table 11 is released due to the application of negative pressure by the air suction / exhaust mechanism 11AR, and the air suction / exhaust mechanism 11AR sequentially and selectively supplies air to the suction grooves 11g and other suction grooves 12g in zones required to lift or suspend the object instead (step S40).

[0086] Fig. Figure 18 illustrates the air supply. The air intake / exhaust mechanism 11AR initially supplies air to the intake grooves 11g in the zones corresponding to the position of the object under the control of the controller C. When the air supply begins, a back side of the film F, which was previously in contact with the production table 11, experiences an upward force from the air, and the entire film F or a part of the film F, together with the object, is slightly lifted or floated. In this way, the film F and the object completely or partially release contact with the production table 11 to facilitate transport by applying a force in the horizontal direction. Fig. In the example illustrated in Fig. 18, the blowing out of air from the suction grooves 12g of the auxiliary table 12, which has not yet reached the object, is stopped.

[0087] The coating unit 30 moves at a time when the non-contact state is reached, so that the film gripper 52 moves in the negative y-axis direction to the standby position 52a. The film gripper 52 holds the film F lifted by air, so that when the film gripper 52 moves from a position above the production table 11 to a position above the auxiliary table 12, the film F and the object thereon move (step S41).

[0088] The Fig. 19 and Fig. 20 illustrate the movement. As in Fig. As illustrated in Figure 19, when transporting the object attached to the film F, the controller C causes the air intake / exhaust mechanism 11AR to supply air from the suction grooves 11g and 12g in the zones corresponding to the position of the object and to stop the air supply from the suction grooves 11g and 12g outside these zones. The object is thus transported while, as shown in Fig. 20, together with a part of the film F or the entire film F is raised relative to the production table 11 and the auxiliary table 12.

[0089] After the movement of the film F and the object to the auxiliary table 12 is completed, the film gripper 52 releases the film F (step S42). Subsequently, the coating unit 30, to which the film gripper 52 is attached, is moved in the y-axis direction and returned to the standby position (step S43), and the film gripper 52 is released from the coating unit 30 (step S44).

[0090] In addition, the auxiliary table 12, on which the object is mounted 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 mounting section 12F in the normal position 12a, and the operator detaches the auxiliary table 12 from the mounting section, places the object together with the auxiliary table 12 on a pre-prepared transport holder CV, and transports them out of the stereolithography device 1, as shown in Fig. 21 (step S45). This enables transport without direct contact with the object, thereby reducing the risk of breakage and the like and enabling stable transport.

[0091] The above describes the processes / method for manufacturing and subsequently removing the object provided by the stereolithography 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 formed, the object can be removed easily and safely.

[0092] Specifically, air can be supplied to the plurality of suction grooves to create a negative pressure on the surface of the production table 11 during production. The auxiliary table 12 serves as an interface for separately removing the object from the production table 11, and air supply can be provided in the auxiliary table 12 as well as in the production table 11. Even if an object has a large size and a large area, the object can be lifted by air so that it does not come into contact with the production table 11 and the auxiliary table 12, facilitating the horizontal transport (transfer) of the object while holding the film underneath the object.

[0093] Furthermore, the auxiliary table 12 is designed such that it can be detached from the mounting portion 12F. In other words, the auxiliary table 12 itself is portable. The object taken from the production table 11 can thus be transported outward together with the auxiliary table 12. This enables transportation without contact with the object, thus ensuring stable transportation with a reduced risk of breakage and the like. <details zu der geneigten belichtung>

[0094] Fig. 22 is a schematic diagram of the inclined exposure performed by the projectors 21 of the stereolithography apparatus 1 according to the present embodiment.

[0095] First, Fig. 22 the exposure corresponding to a character pattern PT that the projectors 21 execute at specific positions under control of the controller C.

[0096] As described above, in the stereolithography apparatus 1 according to the present embodiment, the projection (exposure) pattern (data) is supplied while the projectors 21, which are arranged to be slightly inclined with respect to the y-axis direction, are moved stepwise or continuously in the y-axis direction to project the pattern. In practice, the exposure unit 20 includes four projectors 21 (21a to 21d) arranged at regular intervals in the x-axis direction, and the four projectors 21a to 21d perform exposure simultaneously. Fig. Fig. 22 illustrates the operation using the projectors 21a and 21b as examples. That is, the four projectors 21 alternately perform a stepwise or continuous movement My1 in the negative y-axis direction and a movement My2 in the positive y-axis direction between one end in the positive y-axis direction and one end in the negative y-axis direction of the drawing surface DA with an intermediate stepwise movement Mx in the positive x-axis direction, and perform projection (drawing) according to the projection (exposure) pattern during the movement My1 and the movement My2.

[0097] The Fig. 23 and Fig. 24 are diagrams each explaining a pixel arrangement and an inclination of a projector 21. The projector 21 has a configuration in which a plurality of pixels PXL are arranged in a two-dimensional (e.g., rectangular) arrangement, and ON-OFF states of the exposure light at the respective pixels PXL can be individually switched under control of the controller C according to the exposure pattern data. The pixels PXL1 in the ON state and the pixels PXL2 in the OFF state are in Fig. 23 are distinguished from each other.

[0098] The projector 21 is arranged so that it is tilted with respect to the y-axis direction forming the movement direction. Specifically, in the exposure unit 20, with the pixels PXL arranged (actually slightly tilted) in the y-axis direction (a vertical direction in the figure), the projector 21 is tilted so that the center positions PXLc of adjacent pixels PXL are offset by a pitch Re in the x-axis direction, where Re (µm) forms a required pitch. Such an inclination results in the pitch Re in the x-axis direction.

[0099] In the y-axis direction (a scanning direction) in which the projector 21 performs the movement My1 and the movement My2, exposure is performed, while the exposure pattern is switched each time a feed movement of the projector 21 is performed by the distance Re. That is, switching of drawing (exposure control) is performed each time the distance Re is moved to obtain the drawing pitch Re in the y-axis direction.

[0100] More precisely, the equation Px:h = n: 1 (n is an integer) is preferably used, where, as in Fig. 24, P (µm) is the size of each pixel PXL (one pixel pitch), Px (µm) is the projection size of the size in the x-axis direction, and h (µm) is the projection size of the size in the y-axis direction. For example, in a case where the projector 21 includes pixels in a 1920 × 1080 array, the equation n = 24 is preferably used in view of high flexibility in setting the exposure conditions.

[0101] It is assumed that the character pitch Re is smaller than the pixel size P. Turning on or off the exposure of each of the pixels PXL of the projector 21 at a certain position is determined based on whether a center position PXLc of them lies within the character pattern PT. Fig. For example, Fig. 23 shows the pixels PXL1 being set to the ON state and the pixels PXL2 being set to the OFF state in the case where the projector 21 performs exposure according to the character pattern PT.

[0102] In the present embodiment, in the projector 21 including the pixels PXL in the rectangular array, a distance in the x-axis direction between a position P1, which is one end in the negative x-axis direction and also in the positive y-axis direction, and a position P2, which is one end in the positive x-axis direction and also in the positive y-axis direction, is referred to as a character width L, as shown in Fig. 23. The character width L is a width in the x-axis direction of a stripe area extending in the y-axis direction as an exposure area during movement of the projector 21 in the y-axis direction. Since the projector 21 is tilted in the strict sense, exposure is also performed in a rectangular area with a width ΔL in the x-axis direction between the aforementioned position P2 and a position P3, which is one end in the positive x-axis direction and also in the negative y-axis direction of the projector 21, while the projector 21 moves in the y-axis direction, but the area forms an overlap area (also called a "joint portion") with a stripe area in the next exposure in the y-axis direction and typically includes at most approximately two to three pixels in the x-axis direction.

[0103] Fig. Fig. 25 is a diagram illustrating a change in an exposure pattern when the character area DA is exposed for each character width L according to a predetermined character pattern while the projector 21 is moving. The projector 21 performs stripe exposure while moving stepwise in the y-axis direction. The exposure patterns at arbitrary times t = t(n), t(n+1), t(n+2), and t(n+3) are therefore, as shown in Fig. 25 illustrates, different. However, when viewed locally, different pixels PXL arranged along the y-axis direction of the projector 21 sequentially expose the same position in the drawing surface DA as the projector 21 moves, and as a result, exposure is performed with substantially the same amount of exposure light (accumulated amount of light) at one position in the drawing surface DA. The stereolithography apparatus 1 according to the present embodiment performs exposure in this way and can thus expose the drawing surface DA with high resolution while the exposure unit 20 is moved at high speed. <Verschiebung des Verbindungsabschnitts der Streifenbereiche>

[0104] As in the Fig. 23 and Fig. 25, the connecting portion having the width ΔL is formed in adjacent stripe regions when the character area DA is exposed for each character width L. In the stereolithography apparatus 1 according to the present embodiment, in which formation (lamination) of the slurry film and exposure are alternately performed to obtain the three-dimensional object, the connecting portion is formed in each layer.

[0105] The Fig. 26 and 27 A to C are diagrams each explaining the exposure by which the effect of connecting sections can be avoided. Fig. Figure 26 shows the exposure in two vertically adjacent layers when N slurry films are used to produce the object. For better illustration, Fig. 26 only one character pattern PT is shown, but the character pattern PT can differ from layer to layer.

[0106] Basically, in the present embodiment, the position of the connecting portion in the plane when the respective layer is exposed is deliberately shifted from the position of the connecting portion in the plane (a horizontal position) in another layer.For example, in a case where a character area DA (DA1) of a lower slurry film is exposed for each character width L by making the projector 21 perform a reciprocating movement as indicated by an arrow AR31a and an arrow AR31b, a character area DA (DA2) of a slurry film formed thereon is adjusted so that a connecting portion JT (JTb) therein is shifted by L / N in the positive x-axis direction from a connecting portion JT (JTa) in the layer immediately below the layer, and the character area DA2 is similarly exposed for each character width L by making the projector 21 perform a reciprocating movement as indicated by an arrow AR32a and an arrow AR32b in FIG. Fig. 26. In the present disclosure, the "in-plane position" refers to a position on the surface of the slurry film SLF when viewed in a direction perpendicular to the slurry film SLF.

[0107] In a case where the displacement is performed in each layer, in the object as the laminated body LB of slurry films, the connecting portion JT (JT1, JT2, JT3 ...) of adjacent stripe regions in each layer is displaced in the horizontal direction for each layer, as shown in a cross-sectional view in Fig. 27 A. In this case, a displacement amount of a joint portion in a slurry film SLF constituting a k-th layer (1 ≤ k ≤ N) counted from below from a joint portion in a slurry film to constitute a first layer is represented by (k - 1) - (L / N).

[0108] Although it is in Fig. 26, it appears as if the drawing area DA does not cover the character pattern PT as the lamination proceeds, but this is for illustrative purposes only. The size of the drawing area is determined according to the character pattern PT in each layer, and exposure is performed in each layer as a stripe exposure aligned with the drawing area DA, which is adjusted to cover the character pattern PT, while performing the position shift of the connecting portion JT.

[0109] The type of displacement of the connecting section JT (JT1, JT2, JT3 ...) is not limited to a displacement in one direction, as in Fig. 27 A, but may be a displacement that is substantially uniform in the horizontal direction, such as by means of a cross-sectional view in Fig. 27 B. The displacement amount of the connecting portion within the slurry film SLF, which in this case is the k-th layer, is given by (-1) k-1- (k-1)-(L / N) expressed in terms of the direction of displacement.

[0110] More generally, the displacement amounts in a first direction of the connecting portion JT in the respective layers of the N slurry films relative to the position of the connecting portion JT in the first layer are integer multiples of L / N and vary among each other.

[0111] The exposure state of the connecting portion differs from that of the other parts in the narrow sense. In the present embodiment, the position of the connecting portion JT in each layer is varied (distributed) in the plane and averaged in the object as the laminated body LB of the slurry films, for example, as shown in Fig. 27 A or Fig. 27 B. Alternatively, the in-plane position of the joint portion JT may be different between at least two layers of the laminated body LB. In this way, the impact of the joint portion on the manufacturing accuracy can be appropriately suppressed, and the object can be manufactured with high dimensional accuracy. For example, even in a case where lamination and exposure are repeated for tens or hundreds of slurry films, the accumulation of effects on the manufacturing accuracy in the joint portion (more specifically, a volume change caused by an energy change due to overlap exposure) can be reduced.

[0112] As described above, according to the present embodiment, in a case where the formation (lamination) of the slurry film and the exposure are repeated to obtain the three-dimensional object, the inclined pattern is used for exposing each layer with the projector to sequentially expose a plurality of stripe regions according to the character width of the projector. The in-plane position of the connecting portion in adjacent stripe regions in at least one layer is then shifted from the in-plane position of the connecting portion in at least one other layer. In this way, the effect of the presence of the connecting portion on the manufacturing accuracy can be appropriately reduced, and the object can be manufactured with high dimensional accuracy.

[0113] The position of the connecting section JT (JT1, JT2, JT3 ...) in each layer may be the same in the horizontal direction, as shown by a cross-sectional view in Fig. 27 C illustrates. <Gleichzeitige Formung eines Aufschlämmungsabgabebereichs>

[0114] The fabrication of the object with simultaneous formation of the slurry discharge area will be described next as an example of the fabrication of the object in the stereolithography apparatus 1 according to the present embodiment. Fig. 28 to 32 are side views schematically showing the stereolithography apparatus 1 during manufacturing in a case where the slurry discharge portion is formed simultaneously.

[0115] Here, the slurry discharge region is a region where a slurry SL is applied upon formation of each layer in a case where the object is formed as the laminated body LB of the slurry films. Simultaneous formation of the slurry discharge region refers to a scheme in which, before the formation of a layer other than the first layer (a lowermost layer), a slurry discharge region for a layer to be formed next is formed simultaneously with the formation of an immediately underlying layer by exposure curing the slurry. When the first layer is formed, a target area for slurry discharge on the upper surface of the production table 11 to which the film F is sucked and fixed is regarded as the slurry discharge region.

[0116] First of all, Fig. 28 shows a state after formation of the first layer (lowest layer). The first layer is formed according to the above-mentioned methods by applying the slurry SL from the slurry discharge pump 40 onto the film F sucked and fixed to the production table 11, scraping the slurry SL into a slurry film SLF1 by the coater 31, and exposing the slurry film SLF1 according to a predetermined exposure pattern.

[0117] However, in the formation of the first layer, the slurry film SLF1 is formed not only in an object formation region RE1 where slurry application is causally required for the production of the object, but also in such a way that it is continuous with a slurry discharge region RE2 located in a predetermined range further in the positive y-axis direction (closer to a wiping position of the coater 31) than the object formation region RE1, and a boundary region RE3 between the object formation region RE1 and the slurry discharge region RE2. Moreover, an extent of the slurry film formation region SLF1 is set such that a position of the center of gravity in a horizontal plane of the slurry film SLF1 is substantially the same as or close to a position of the center of gravity in a horizontal plane of the production table 11.

[0118] The object formation region RE1, where the slurry dispensing or application is necessary for the fabrication of the object, is a region where a light-cured part becomes the object. On the other hand, in the slurry dispensing region RE2, a light-cured part of an m-th layer (m is an integer equal to or greater than two) serves as a slurry dispensing table for one layer (m+1).

[0119] In the subsequent exposure, the area for forming the object RE1 is exposed according to the drawing pattern PT, and the area for discharging the slurry RE2 is exposed together with it.

[0120] Next, Fig. 29 illustrates the release of the slurry SL to form a second layer. Fig. 30 shows the state after the formation of the second layer.

[0121] The second layer is formed by forming a slurry film SLF2 on the previously formed slurry film SLF1 (first layer). In this case, the slurry SL is applied to the slurry discharge region RE2 of the first layer. The slurry discharge region RE2 is cured and stable by exposure to light, so that the slurry SL can be discharged by the slurry discharge pump 40 and then scraped off by the coater 31 in an appropriate manner. In the formation of the second layer, the slurry film SLF2 is formed such that the object formation region RE1, the slurry discharge region RE2, and the boundary region RE3 are continuous, as in the first layer.The slurry film SLF2 is formed on the slurry film SLF1 such that a position of the center of gravity in a horizontal plane of the slurry films as a whole is still substantially the same as or close to the position of the center of gravity in the horizontal plane of the manufacturing table 11.

[0122] In the subsequent exposure, the area for forming the object RE1 is exposed according to the drawing pattern PT, and the area for discharging the slurry RE2 is also exposed, as in the formation of the first layer.

[0123] Similarly, a slurry film SL for forming each of the subsequent layers is coated on the slurry discharging region RE2 formed immediately before the formation of the layer, the slurry film SL is scraped off by the coater 31 to continuously form the slurry film SLF in the object forming region RE1, the slurry discharging region RE2, and the boundary region RE3, and the exposure of the object forming region RE1 corresponding to the drawing pattern PT and the exposure of the slurry discharging region RE2 are performed.

[0124] In this case, the position of the center of gravity in the horizontal plane of the slurry films as a whole is always substantially the same as or close to the position of the center of gravity in the horizontal plane of the production table 11. Thus, the effect of prestress on the production table 11 is appropriately reduced even when a large number of layers are stacked or laminated, resulting in a heavy object weight. This appropriately suppresses the reduction in production accuracy (especially exposure accuracy) caused by prestress.

[0125] The slurry for forming each layer is applied to the immediately previously formed slurry delivery area RE2 as part of the slurry film and cured by exposure to light, which enables stable stripping.

[0126] Fig. Figure 31 shows the object formed as a laminated body LB of the slurry films by repeated formation of the slurry films SLF and exposure as described above. As shown in Fig. 31, the laminated body LB includes a laminated portion LB1 as a causative object, a laminated portion LB2 in the slurry discharging region RE2 provided for each layer, and an uncured laminated portion LB3 in the boundary region RE3 also provided for each layer.

[0127] The laminated body LB is finally transported out of the apparatus together with the auxiliary table 12 according to the above-mentioned methods, and in this case, the uncured laminated portion LB3 is located between the laminated portion LB1 and the laminated portion LB2, so that it is easy to separate the laminated portion LB1 from the laminated portion LB2 and further remove the laminated portion LB3 after the transport.

[0128] Fig. 32 is a diagram showing the manufacturing (slurry discharge SL) in a case where an object has a small planar size relative to the manufacturing table 11. In this case, the slurry film SL for forming each of the subsequent layers is also coated on the slurry discharge region RE2 formed immediately before, the slurry film SL is scraped off by the coater 31 to continuously form the slurry film SLF in the object formation region RE1, the slurry discharge region RE2, and the boundary region RE3, and the exposure of the object formation region RE1 corresponding to the drawing pattern PT and the exposure of the slurry discharge region RE2 are performed as in the above-described case.

[0129] Furthermore, the position of the center of gravity in the horizontal plane of the slurry film as a whole in the formation of the first layer can be selected to be substantially the same as or close to the position of the center of gravity in the horizontal plane of the production table 11, a position of the center of gravity in a horizontal plane of the laminated body formed thereafter can be maintained to be substantially the same as or close to the position of the center of gravity in the horizontal plane of the production table 11, and the application of the prestress to the production table 11 can be reduced as in the above-mentioned case.

[0130] Also in this case, the slurry discharge region RE2 is formed at a position (specifically, at a position near the object formation region RE1 and closer to the center than in a case where the object has a larger planar size) and has a size corresponding to the planar size of the object, so that the slurry film SLF including the object formation region RE1 having a required size can be formed using the slurry SL discharged in a minimum required discharge amount.

[0131] These effects can never be achieved in a case where a slurry is applied to a liftable application fixture (the auxiliary table) provided on one side of the manufacturing table and a slurry film is layered by scraping the slurry, as disclosed in JP 2017-124631 A. Assuming that an object with a small size, as in Fig. 32, manufacturing is performed at the center of the manufacturing table using such an application fixture, the slurry must be scraped from the application fixture toward the center, so that the slurry must be provided for scraping in an amount larger than that required for manufacturing, which is disadvantageous in terms of cost. If a position near the application fixture is set as the manufacturing position to avoid the above-mentioned problem, manufacturing must be performed at one end of the manufacturing table, thereby causing a problem of preload. Both of these disadvantages can be overcome by the above-described manufacturing in the course of forming the slurry discharging area RE2.

[0132] As described above, according to the present embodiment, in the course of forming the slurry film by scraping the slurry using the coater, the slurry film is formed to include, in addition to the object formation region where the application of the slurry is causally required for the production of the object, the slurry discharge region located closer than the slurry discharge region within a predetermined range, and the boundary region between the object formation region and the slurry discharge region, wherein the position of the center of gravity in the horizontal plane of the slurry film is selected to be substantially the same as or close to the position of the center of gravity in the horizontal plane of the production table.Furthermore, when the area for forming the object according to the pattern is exposed, the area for discharging the slurry is also exposed. This appropriately suppresses the application of prestress to the production table, and the reduction in production accuracy (exposure accuracy) caused by prestress is also appropriately suppressed, even in cases where the object is heavy.On the other hand, in a case where the object has a small planar size, the slurry discharge region may be formed at the position and in the size corresponding to the planar size of the object, so that the slurry film including the object formation region having a required size can be formed using the slurry discharged in a minimum required discharge amount while appropriately suppressing the application of the prestress to the fabrication table. <Weitere Ausführungsformen>

[0133] In the above-mentioned embodiment, the slurry obtained by kneading the mixture of the light-curing resin and the ceramic powder is used as the light-curing material. Alternatively, a slurry containing only the light-curing resin and not the ceramic powder may be used, or a slurry containing another material, such as metal powder, may be used instead of the ceramic powder.

[0134] In the above-mentioned embodiment, the plurality of suction grooves 11g and 12g are used as the plurality of air supply ports of the production table 11 and the auxiliary table 12. Grooves or a plurality of holes provided in the production table 11 and / or the auxiliary table 12 separately from the plurality of suction grooves 11g and 12g may be used as the air supply ports instead. In this case, the pneumatic pump of the air suction / exhaust mechanism 11AR is connected to the plurality of air supply ports. Instead of the plurality of suction grooves 11g and 12g for vacuum suction (and air supply), a plurality of suction holes in the production table 11 and / or the auxiliary table 12 may also be used. If the auxiliary table 12 separately has a plurality of air supply ports, the plurality of suction grooves 11g may be omitted.

[0135] In the embodiment described above, the film is suctioned and fixed to the production table 11. The film can be fixed to the production table 11 by pulling it downward while its opposite ends are held by a gripper.

[0136] In the above-mentioned embodiment, a transport device (carrier) including the suction gripper unit 51 and the film gripper 52 is used as the transport means. Instead, a transport device including a holding device (holder) with a different configuration may be used. The transport device may include an actuator for film transport. In the above-described embodiment, the film fixed on the auxiliary table 12 can be transported to the production table 11 while being held by the gripper. The film fixed on the production table 11 can be transported to the auxiliary table 12 while being sucked by a suction gripper.

[0137] In the embodiment described above, the exposure unit 20 is used as the light source, including the projectors 21 as the exposure device. Instead, laser scanning with a galvanometer mirror and another light source, such as a liquid crystal switch, may be used.

[0138] In the above-described embodiment, the device that forms the three-dimensional object by applying the slurry and exposing it to light is used as a stereolithography device to obtain the three-dimensional object. Instead, a device that forms the three-dimensional object by the free liquid level method using an exposure unit similar to the exposure unit 20 in the above-described embodiment may be used. Fig. Figure 33 is an overview of a device that forms the three-dimensional object by the free liquid level method. Fig. The apparatus shown in Figure 33 includes a tank 101 containing a photocurable resin in a liquid state as the photocurable material, a fabrication table 102 on which a three-dimensional object LB is mounted, and a projector 103 similar to that in the above-mentioned embodiment. Furthermore, an apparatus that forms the three-dimensional object by the controlled liquid level method or another method can be used as a stereolithography apparatus to obtain the three-dimensional object.< / details>

Claims

[1] Stereolithography device (1) for producing a three-dimensional object, comprising: an exposure device (20) for exposing a photocurable material according to an exposure pattern generated in advance on the basis of three-dimensional shape data; and a control device (C) for controlling the operation of the stereolithography device (1), wherein the exposure device (20) comprises: a projector (21) comprising a plurality of pixels (PXL) in a two-dimensional array and adapted to individually switch ON-OFF states of exposure light at the respective pixels (PXL), wherein the projector (21) is movable in a second direction (y) orthogonal to a first direction (x) in a posture inclined with respect to the second direction (y), so that center positions of two adjacent pixels (PXL) of the plurality of pixels (PXL) are spaced from each other by a predetermined character pitch (Re) in the first direction (x), and is adapted to switch the ON-OFF states of the exposure light each time the projector (21) moves by a distance corresponding to the character pitch (Re) in the second direction (y), and the control device (C) causing the projector (21) to expose the light-curable material in a predetermined character area successively for a plurality of stripe areas (L) each extending in the second direction (y) and having a predetermined character width in the first direction (x) by individually switching the ON-OFF states of the exposure light at the respective pixels on the basis of the exposure pattern while alternating a forward movement and a backward movement in the second direction (y) with an intermediate step movement in the first direction (x), and in a case where a plurality of layers of the photocurable material are each exposed by the exposure device (20) while being stacked on top of one another to obtain the three-dimensional object, forming a connecting portion (JT) of two adjacent stripe regions (L) of the plurality of stripe regions (L) by overlapping the adjacent stripe regions (L) along the first direction (x) and causing an in-plane position of the connecting portion (JT) to differ between at least two layers of the plurality of layers. [2] The stereolithography apparatus (1) according to claim 1, wherein, in a case where the plurality of layers of the photocurable material are respectively exposed by the exposure means (20) while being stacked to obtain the three-dimensional object, the control means (C) causes the in-plane position of the connecting portion (JT) to differ between the plurality of layers. [3] Stereolithography device (1) according to claim 2, wherein the in-plane position of the connecting portion (JT) when the projector (21) exposes each of the plurality of layers is shifted by an integer multiple of L / N in the first direction (x) relative to the in-plane position of the connecting portion (JT) in a layer which is exposed first among the plurality of layers, where L is the character width and N is the number of layers stacked on top of each other. [4] Stereolithography device (1) according to one of claims 1 to 3, further comprising: a production table (11); a dispensing device (40) adapted to dispense a slurry as a light-curable material onto the production table (11); and a scraping device (30) for scraping the slurry discharged onto the production table (11) to form a slurry film having a predetermined thickness, wherein the control device (C) repeats the discharge of the slurry by the discharge device (40) and the scraping of the discharged slurry by the scraping device (30) to stack a plurality of slurry films as the plurality of layers. [5] Stereolithography device (1) for producing a three-dimensional object, comprising: a production table (11); an exposure device (20) for exposing a photocurable material according to an exposure pattern generated in advance on the basis of three-dimensional shape data; and a dispensing device (40) adapted to dispense a slurry as a light-curable material onto the production table (11); and a scraping device (30) for scraping the slurry discharged onto the production table (11) to form a slurry film having a predetermined thickness, wherein a control device (C) for controlling the operation of the stereolithography device (1), wherein the exposure device (20) comprises: a projector (21) comprising a plurality of pixels (PXL) in a two-dimensional array and adapted to individually switch ON-OFF states of exposure light at the respective pixels (PXL), wherein the projector (21) is movable in a second direction (y) orthogonal to a first direction (x) in a posture inclined with respect to the second direction (y), so that center positions of two adjacent pixels (PXL) of the plurality of pixels (PXL) are spaced from each other by a predetermined character pitch (Re) in the first direction (x), and is adapted to switch the ON-OFF states of the exposure light each time the projector (21) moves by a distance corresponding to the character pitch (Re) in the second direction (y), and the control device (C) causing the projector (21) to expose the light-curable material in a predetermined drawing area successively for a plurality of stripe areas (L) each extending in the second direction (y) and having a predetermined character width in the first direction (x) by individually switching the ON-OFF states of the exposure light at the respective pixels (PXL) on the basis of the exposure pattern while alternating a forward movement and a backward movement in the second direction (y) with an intermediate step movement in the first direction (x), and in a case where a plurality of layers of the photocurable material are each exposed by the exposure device (20) while being stacked on top of one another to obtain the three-dimensional object, the dispensing of the slurry by the dispensing device (40) and the scraping of the dispensed slurry by the scraping device (30) are repeated to stack a plurality of slurry films as the plurality of layers, and a connecting portion (JT) of two adjacent stripe regions (L) of the plurality of stripe regions (L), when the plurality of slurry films are respectively formed, at least the dispensing device (40) and the wiping device (30) are controlled so that each of the slurry films comprises not only a first region, but also a second region and a third region, wherein the first region is a region in which the application of the slurry is originally required for the production of the three-dimensional object, the second region is a region which is closer to a wiping device start position than the first region in a predetermined range, and the third region is a region between the first region and the second region, causes the position of the center of gravity in a horizontal plane of each of the slurry films to be substantially the same as or close to the position of the center of gravity in a horizontal plane of the production table (11), the exposure device (20) causes the second area to be exposed when the first area is exposed according to the exposure pattern, and causes, when an m-th layer of the plurality of slurry films is formed, the dispensing means to dispense the slurry onto the second region of an (m-1) layer of the slurry films, where m is an integer equal to or greater than two. [6] A method for producing a three-dimensional object, comprising: an exposure step of exposing a photocurable material according to an exposure pattern generated in advance on the basis of three-dimensional shape data, using a projector (21) comprising a plurality of pixels (PXL) in a two-dimensional array and adapted to individually switch ON-OFF states of exposure light at the respective pixels (PXL), wherein in the exposure step, the projector (21) is caused to expose in a posture that is inclined with respect to a second direction (y) orthogonal to a first direction (x) so that center positions of two adjacent pixels (PXL) of the plurality of pixels (PXL) are spaced from each other by a predetermined character pitch (Re) in the first direction (x), the light-curable material is exposed in a predetermined character area successively for a plurality of stripe regions (L) each extending in the second direction (y) and having a predetermined character width in the first direction (x) by switching the ON-OFF states of the exposure light at the respective pixels (PXL) individually on the basis of the exposure pattern each time the projector (21) moves by a distance corresponding to the character pitch (Re) in the second direction (y),while a forward movement and a backward movement in the second direction (y) are alternated with an intermediate step movement in the first direction (x), and, in a case where a plurality of layers of the photocurable material are each exposed in the exposure step while being stacked on top of each other to obtain the three-dimensional object, a connecting portion (JT) of two adjacent stripe regions of the plurality of stripe regions (L) is formed by overlapping the adjacent stripe regions (L) along the first direction (x), and an in-plane position of the connecting portion (JT) is caused to differ between at least two layers of the plurality of layers.

Images