Additive manufacturing system and additive manufacturing method

Abstract

The invention discloses an additive manufacturing system which comprises a forming platform capable of moving in a first direction; the first bearing device is configured to bear a first material; a second carrying device configured to carry a second material different from the first material; an optical unit configured to project light to allow the first material or the second material to cure based on a preset pattern; and a cleaning unit configured to separate the uncured material adhering to the cured object of the forming platform from the cured object, where the cleaning unit includes at least one absorbent layer configured to allow the uncured material to flow into the apertures of the absorbent layer. The cleaning unit can separate the uncured material on the cured object adhered to the forming platform from the cured object, so that the risk of mixing of the uncured first-class material and the second-class material borne by the bearing device in the subsequent steps is reduced.

Description

Technical Field

[0001] This disclosure relates to the field of additive manufacturing, and more specifically, to an additive manufacturing system and an additive manufacturing method. Background Technology

[0002] Additive manufacturing (or 3D printing) technology creates three-dimensional entities by layering data from a three-dimensional model of an object. Additive manufacturing includes technologies such as FDM, SLS, SLA, DLP, and LCD. Photopolymerization technologies, represented by DLP and LCD, can manufacture products with high precision.

[0003] Currently, there is an increasing demand for products that require multiple materials; for example, the outer edges of a product may require a softer material, while the interior may require a harder material. Constructing a target object using multiple different materials is challenging; for instance, when using various materials, the materials in different containers holding different materials can gradually become contaminated by the other materials. Therefore, an improved additive manufacturing system is needed. Summary of the Invention

[0004] This application provides an additive manufacturing system comprising: a first carrier device configured to carry a first material; a forming platform configured to move along a first direction to approach or move away from the first carrier device; a first actuator for the first carrier device movable between a first height level and a second height level, wherein, at the first height level, the first actuator is configured to move along a second direction perpendicular to the first direction to allow at least a portion of the first material carried by the first carrier device to be held at a first predetermined height; at the second height level, different from the first height level, the first actuator is movable along a second direction; and an optical unit configured to project light onto the first material at the first predetermined height to allow the first material to cure based on a preset pattern. The first actuator allows for a variety of uses.

[0005] In some embodiments, the first support device is formed as a plate-shaped element or a box-shaped element.

[0006] In some embodiments, when the first support device is formed as a plate-shaped element, the first actuator is configured to move in a second direction so that all the first material carried by the first support device is held at a first predetermined height.

[0007] In some embodiments, the first carrier includes at least one collection container configured to collect the first material propelled by the first actuator.

[0008] In some embodiments, the additive manufacturing system includes at least one collection container configured to be spaced apart from the first support device and to collect first material propelled by the first actuator.

[0009] In some embodiments, when the first support device is formed as a box-shaped element, the first actuator is configured to move in a second direction such that a portion of the first material carried by the first support device is held at a first predetermined height, and the remainder of the first material carried by the support device is above the first predetermined height.

[0010] In some embodiments, the first actuator includes a lower portion configured to prevent the flow of first material through the lower portion.

[0011] In some embodiments, the additive manufacturing system further includes a first feeding mechanism configured to supply a first material to a first support device.

[0012] In some embodiments, the first feeding mechanism is configured to be stationary or movable relative to the first carrying device.

[0013] In some embodiments, the second altitude level is higher than the first altitude level; or the second altitude level is lower than the first altitude level.

[0014] In some embodiments, the first actuator is configured to move between a first height level, a second height level, and a third height level, wherein the first height level is between the second height level and the third height level.

[0015] In some embodiments, the first predetermined height is 50μm to 1000μm, for example 100μm to 800μm, for example 200μm to 500μm, for example 300μm to 400μm.

[0016] In some embodiments, the additive manufacturing system further includes a cleaning unit configured to separate uncured first material adhering to a cured object on a molding platform from the cured object.

[0017] In some embodiments, the cleaning unit includes at least one of an airflow assembly, a wiping assembly, an adsorption assembly, a cleaning container, a spraying assembly, or a heating assembly.

[0018] In some embodiments, the additive manufacturing system further includes a second support device configured to carry a second material, wherein the second material is different from the first material.

[0019] In some embodiments, the additive manufacturing system further includes a second actuator for a second support device, the second actuator being movable to different height levels along a first direction.

[0020] This application also provides an additive manufacturing method, comprising: moving a molding platform along a first direction to approach or move away from a first support device; maintaining a first actuator at a first height level; when the first actuator is at the first height level, driving the first actuator to move along a second direction perpendicular to the first direction, so that at least a portion of the first material carried by the first support device is maintained at a first predetermined height; using an optical unit to project light onto the first material at the first predetermined height, so as to allow the first material to solidify based on a preset pattern; and driving the first actuator to move along the first direction to a second height level different from the first height level.

[0021] In some embodiments, the additive manufacturing method further includes: driving the first actuator to move along a second direction when the first actuator is at a second height level, so that at least a portion of the first material carried by the first carrier is maintained at a second predetermined height, the second predetermined height being lower than the first predetermined height; driving the first actuator to move along a first direction from the second height level to the first height level; and using an optical unit to project light onto the first material at the first predetermined height, so as to allow the first material to cure based on a new preset pattern.

[0022] In some embodiments, the additive manufacturing method further includes: driving the first actuator to move in a second direction when the first actuator is at a second height level, so that at least a portion of the first material carried by the first carrier is held at a third predetermined height, the third predetermined height being higher than the first predetermined height; and using an optical unit to project light onto the first material at the third predetermined height to allow the first material to cure based on a new preset pattern.

[0023] In some embodiments, the additive manufacturing method further includes: after curing the first material, moving at least one of a molding platform and a second carrier device carrying the second material to align the molding platform with the second carrier device; and using an optical unit, projecting light onto the second material carried by the second carrier device to cure the second material based on a new preset pattern.

[0024] The additive manufacturing system provided in this application is advantageous for obtaining high-quality objects using multi-material photopolymerization printing. The first actuator, capable of operating at multiple heights, helps maintain different liquid levels, thereby achieving the desired printing effect.

[0025] This application also provides an additive manufacturing system comprising: a molding platform movable along a first direction; a first carrier configured to carry a first material; a second carrier configured to carry a second material different from the first material; an optical unit configured to project light to allow the first material or the second material to cure based on a preset pattern; and a cleaning unit configured to separate uncured material adhering to a cured object on the molding platform from the cured object.

[0026] In some embodiments, the cleaning unit includes at least one of an airflow assembly, a wiping assembly, an adsorption assembly, a cleaning container, a spraying assembly, or a heating assembly.

[0027] In some embodiments, the airflow assembly is configured to apply a positive or negative pressure airflow to the solidified object.

[0028] In some embodiments, the adsorption component includes a sponge or a fabric.

[0029] In some embodiments, the cleaning container is configured to contain cleaning agent.

[0030] In some embodiments, the absorbent layer is made of a soft, porous material.

[0031] This application also provides an additive manufacturing system comprising: a molding platform movable along a first direction; a first support device configured to support a first material; a second support device configured to support a second material different from the first material; an optical unit configured to project light rays to allow the first material or the second material to cure based on a preset pattern; and a cleaning unit configured to separate uncured material adhering to a cured object on the molding platform from the cured object, wherein the cleaning unit includes at least one absorbent layer configured to allow uncured material to flow into pores or pores in the absorbent layer. The term "pores or pores" should be understood as features that allow uncured material to flow into or fill, and their shape in space can be configured in various forms.

[0032] In some embodiments, at least one absorbent layer includes a first absorbent layer and a second absorbent layer, the first absorbent layer and the second absorbent layer being composed of different porous materials, such as soft porous materials. Soft porous materials include at least one of the following: polyester fiber products, bio-cellulose products, polyacrylonitrile fiber products, polypropylene fibers or modified polypropylene fibers, wood fiber products, polyethers, polyvinyl alcohol, and polyurethane.

[0033] In some embodiments, the additive manufacturing system further includes a heating element configured to raise the temperature of at least one absorption layer.

[0034] In some embodiments, the additive manufacturing system further includes a pressure assembly configured to apply an airflow to blow away uncured material from a cured object and configured to facilitate the flow of uncured material in the pores of the absorbent layer.

[0035] In some embodiments, the additive manufacturing system further includes a negative pressure assembly configured to force airflow and uncured material to flow through at least one absorbent layer.

[0036] In some embodiments, the positive or negative pressure assembly is equipped with a collection container configured to collect material flowing through at least one absorbent layer.

[0037] In some embodiments, the positive pressure component or the negative pressure component is directly connected to the collection container (or is integrally formed).

[0038] In some embodiments, the absorbent layer is removable or replaceable.

[0039] In some embodiments, the additive manufacturing system further includes a conveying mechanism for conveying the absorbent layer.

[0040] This application also provides an additive manufacturing method, which includes: projecting light to solidify and adhere a first material carried by a first carrier device to a molding platform; using a cleaning unit to separate uncured material on a cured object adhered to the molding platform from the cured object; and projecting light to solidify and adhere a second material carried by a second carrier device to the molding platform.

[0041] The additive manufacturing system provided in this application is advantageous for obtaining high-quality objects using multi-material photopolymerization printing. The cleaning unit enables the separation of uncured material adhering to the cured object on the forming platform from the cured object, thereby reducing the risk of mixing of the uncured first type of material with the second type of material carried by the carrier device in subsequent steps. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and therefore should not be regarded as a limitation on the scope of protection.

[0043] Figure 1 A schematic diagram of a printout including two printing materials is shown;

[0044] Figure 2 A schematic diagram of a printout including two printing materials is shown;

[0045] Figure 3 The support device of the additive manufacturing system is shown;

[0046] Figure 4 The cleaning unit of the additive manufacturing system is shown;

[0047] Figure 5 A schematic diagram of a portion of an additive manufacturing system is shown;

[0048] Figure 6A A schematic diagram of an object obtained by solidifying material in a container with a first liquid level is shown.

[0049] Figure 6B A schematic diagram of an object obtained by solidifying material in a container with a second liquid level is shown.

[0050] Figure 7 A schematic diagram of a portion of an additive manufacturing system is shown;

[0051] Figure 8 A schematic diagram of a portion of an additive manufacturing system is shown;

[0052] Figure 9 Examples of maintaining printing liquid levels are shown;

[0053] Figure 10 Examples of maintaining printing liquid levels are shown;

[0054] Figure 11 Examples of maintaining printing liquid levels are shown;

[0055] Figure 12 Examples of maintaining printing liquid levels are shown;

[0056] Figure 13 Examples of maintaining printing liquid levels are shown;

[0057] Figure 14 Examples of maintaining printing liquid levels are shown;

[0058] Figures 15A-15C Examples of maintaining printing liquid levels are shown;

[0059] Figures 16A-16D Examples of some cleaning units are shown;

[0060] Figures 17A-17D A portion of an additive manufacturing system according to some embodiments is shown;

[0061] Figure 18 Some embodiments of the cleaning unit are shown.

[0062] In the accompanying drawings, some of the same or similar reference numerals represent some of the same or similar elements or components. Detailed Implementation

[0063] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention. The various elements, parts, and components in the embodiments provided in this application can be combined with each other to form new embodiments when they do not contradict each other, and these should fall within the protection scope of this application.

[0064] The terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, or system, product, or apparatus that comprises a series of steps is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0065] Figure 1 A schematic diagram of a printed part comprising two printing materials is shown. The 3D printing equipment or additive manufacturing system 100 includes a forming platform 110 on which the printed part is adhered. A first layer 131 of the printed part is adhered to the forming platform 110, a second layer 132 of the printed part is adhered to the first layer 131, and a third layer 133 of the printed part is adhered to the second layer 132. Layers 131, 132, and 133 of the printed part are entirely composed of material A.

[0066] A fourth layer of the printed material is adhered to the third layer 133. The fourth layer comprises a first portion 1341 made of material A and a second portion 1342 made of material B, which is a material different from material A. The first portion 1341 and the second portion 1342 are spaced apart from each other. The first portion 1341 and the second portion 1342 have the same thickness, for example, 80 μm.

[0067] A fifth layer of the printed material is adhered to the fourth layer. The fifth layer comprises a first portion 1351 made of material A and a second portion 1352 made of material B. The first portion 1351 of the fifth layer is adhered to the first portion 1341 of the fourth layer, and the second portion 1352 of the fifth layer is adhered to the second portion 1342 of the fourth layer. The first portion 1351 and the second portion 1352 have the same thickness, for example, 100 μm.

[0068] A sixth layer of the printed material is adhered to the fifth layer. The sixth layer comprises a first portion 1361 made of material A and a second portion 1362 made of material B. The first portion 1361 of the sixth layer is adhered to the first portion 1351 of the fifth layer, and the second portion 1362 of the sixth layer is adhered to the second portion 1352 of the fifth layer. The first portion 1361 and the second portion 1362 have the same thickness, for example, 90 μm.

[0069] exist Figure 1 In the illustrated embodiment, the first layer 131, the second layer 132, and the third layer 133 are formed first, followed by the fourth, fifth, and sixth layers. The first portion 1341 of the fourth layer is formed first, followed by the second portion 1342. The first portion 1351 of the fifth layer is formed first, followed by the second portion 1352. The second portion 1362 of the sixth layer is formed first, followed by the first portion 1361. In some variations, the order in which the first and second portions are formed in any of the fourth, fifth, or sixth layers is arbitrary.

[0070] Figure 2 A schematic diagram of a printed part comprising two printing materials is shown. The 3D printing equipment or additive manufacturing system 200 includes a forming platform 210 on which the printed part is adhered. A first layer 231 of the printed part is adhered to the forming platform 210, a second layer 232 of the printed part is adhered to the first layer 231, and a third layer 233 of the printed part is adhered to the second layer 232. Layers 231, 232, and 233 of the printed part are entirely composed of material A.

[0071] A fourth layer of the printed material is adhered to the third layer 233. The fourth layer comprises a first portion 2341 made of material A and a second portion 2342 made of material B, which is different from material A. The first portion 2341 and the second portion 2342 are spaced apart from each other. The first portion 2341 and the second portion 2342 have different thicknesses. For example, the thickness of the first portion 2341 is 50 μm, and the thickness of the second portion 2342 is 100 μm.

[0072] A fifth layer of the printed material is adhered to the fourth layer. The fifth layer comprises a first portion 2351 made of material A and a second portion 2352 made of material B. The first portion 2351 of the fifth layer is adhered to the first portion 2341 of the fourth layer, and the second portion 2352 of the fifth layer is adhered to the second portion 2342 of the fourth layer. The first portion 2351 and the second portion 2352 have different thicknesses. For example, the thickness of the first portion 2351 is 100 μm, and the thickness of the second portion 2352 is 50 μm.

[0073] exist Figure 2In the illustrated embodiment, a first layer 231, a second layer 232, and a third layer 233 are formed first, followed by a fourth and a fifth layer. A first portion 2341 of the fourth layer is formed first, followed by a second portion 2342. Similarly, a first portion 2351 of the fifth layer is formed first, followed by a second portion 2352.

[0074] Chinese invention patent applications 202410882604.7 and 202411553164.7 also disclose photopolymerization printing using at least two materials, the entire contents of which are incorporated herein by reference.

[0075] Figure 3 A carrier device for an additive manufacturing system is shown. The additive manufacturing system 300 includes a forming platform 310, an optical unit 360, and carrier devices 380 and 390. Carrier device 380 carries material A, and carrier device 390 carries material B, which is different from material A. Therefore, the additive manufacturing system 300 can form an object comprising material A and / or material B. For example, carrier device 380 moves to align with the forming platform 310 and optical unit 360, and then optical unit 360 projects light (e.g., UV light) through at least a partially transparent bottom of carrier device 380 and cures material A carried by carrier device 380. The cured material A adheres to the forming platform 310 and forms part 331 of the object. Then, carrier device 390 moves to align with the forming platform 310 and optical unit 360, and then optical unit 360 projects light through at least a partially transparent bottom of carrier device 390 and cures material B carried by carrier device 390. The cured material B adheres to the forming platform 310 and forms part 332 of the object.

[0076] In some variations, the support devices 380 and 390 are immovable or stationary, while the forming platform 310 is movable. For example, the forming platform 310 may be moved to align itself with either the support device 380 or the support device 390. In some variations, light projected by a single optical unit 360 can simultaneously radiate to both the support device 380 and the support device 390. In some variations, each support device is assigned one or more optical units 360. It is understood that the support devices, optical units, and forming platform are configured to accommodate the formation of two (or more) materials.

[0077] The type of support device can be designed. For example, an additive manufacturing system includes a support device for supporting material A, a support device for supporting material B, a support device for supporting material C, and a support device for supporting material D. The number of support devices can be designed. For example, an additive manufacturing system includes a support device for a single material A, two support devices for supporting material B, two support devices for supporting material C, and three support devices for supporting material D.

[0078] Figure 4 A cleaning unit of an additive manufacturing system is shown. The additive manufacturing system 400 includes a forming platform 410, an optical unit 460, and carrier devices 480 and 490. The carrier devices 480 and 490 are located between the forming platform 410 and the optical unit 460. The forming platform 410 is movable along the Z-axis or in a stacking direction of multiple layers. For example, the forming platform 410 moves along the Z-axis such that the distance between the forming platform 410 and at least a partially transparent film of the carrier device 480 is 60 μm. Then, the optical unit 460 projects light onto a liquid or paste-like material A contained in the carrier device 480 according to a predetermined pattern, causing the material A between the forming platform 410 and the film of the carrier device 480 to solidify and form a first portion 431. The cross-sectional profile of the first portion 431 conforms to the predetermined pattern, such as a rectangular, circular, or curved closed profile.

[0079] After forming layer 431, the forming platform 410 carrying the first portion 431 leaves the carrier device 480. It is understood that the first portion 431 leaving the carrier device 480 has uncured liquid or paste material A adhering to it. If the first portion 431 leaving the carrier device 480 directly enters the liquid or paste material B carried by the carrier device 490, there is a risk that the adhering material A will contaminate material B (due to the mixing of material A and material B). To at least mitigate this risk, the additive manufacturing system 400 also includes a cleaning unit 470, which is used at least to remove uncured material adhering to the cured object (e.g., the first portion 431).

[0080] The cleaning unit 470 includes, for example, an airflow assembly. In some embodiments, the airflow assembly applies a positive pressure airflow to the cured object to blow off uncured material adhering to the cured object. In some embodiments, the airflow assembly applies a negative pressure airflow to the cured object to adsorb uncured material adhering to the cured object.

[0081] The cleaning unit 470 includes, for example, a wiping assembly. In some embodiments, the wiping assembly includes, for example, a brush or cloth that wipes away uncured material adhering to a cured object. For example, the molding platform 410 remains stationary, and the brush or cloth moves to wipe away uncured material on a first portion 431 carried by the molding platform 410.

[0082] Cleaning unit 470 includes, for example, an adsorption component. In some embodiments, the adsorption component includes a porous material, such as a sponge or cloth, which adsorbs uncured material adhering to a cured object. The cloth includes at least one of the following: polyester fiber products (such as cleanroom wipes), bio-cellulose products (such as felt), polyacrylonitrile fiber products (such as fleece), polypropylene fibers, or modified polypropylene fiber products (such as towels). Alternatively or additionally, the porous material may also include at least one of wood fiber products, polyether, polyvinyl alcohol, and polyurethane. For example, while cleaning unit 470 remains stationary, a first portion 431 carried by molding platform 410 moves to contact the sponge or cloth, causing uncured material on the first portion 431 to penetrate the sponge or cloth.

[0083] The cleaning unit 470 includes, for example, a cleaning container containing a cleaning agent. In some embodiments, the cleaning agent is water, alcohol, or isopropanol, and the first portion 431 carried by the molding platform 410 is immersed in the cleaning agent in the cleaning container. In some embodiments, the cleaning agent is a resin material to be cured. For example, the first portion 431 carried by the molding platform 410 is composed of resin material A, and resin material B is to be cured next. In this case, the first portion 431 is first moved and immersed in the resin material B contained in the cleaning container, so that the resin material A attached to the first portion 431 mixes with the resin material B in the cleaning container. Then, the first portion 431 leaves the cleaning container and moves to the carrier 490 to prepare for the formation of a new portion.

[0084] For some special products, such as dental models that need to meet hygiene requirements or biocompatibility, using cleaning agents different from those used for the model materials may affect the performance of the final product.

[0085] The cleaning unit 470 includes, for example, a spraying assembly. The spraying assembly sprays a liquid to wash away uncured material adhering to a cured object. For example, the spraying assembly sprays water, alcohol, or isopropyl alcohol.

[0086] The cleaning unit 470 includes, for example, a heating component. The heating component is used to transfer heat to uncured material adhering to a cured object. The viscosity of the uncured material changes with temperature, and when the temperature of the uncured material rises to a predetermined value or range, the uncured material easily detaches from the cured object. In some embodiments, the heating component includes a heat-generating component (e.g., a PTC heater) and a heat-conducting component (e.g., a fabric).

[0087] In some embodiments, the cleaning unit 470 includes at least one of an airflow assembly, a wiping assembly, an adsorption assembly, a cleaning container, a spraying assembly, or a heating assembly.

[0088] The molding platform 410 is rotatable so that the uncured material adhering to the cured object is thrown off. The molding platform 410 rotates so that the resin on the first part 431 it carries is thrown off.

[0089] After being cleaned by the cleaning unit 470, the molding platform 410 carrying the first part 431 moves and contacts the material B in the support device 490, and solidifies the material B to form the second part 432. Similarly, the molding platform 410, having left the support device 490, moves to a cleaning position for cleaning by the cleaning unit 470. Then, the molding platform 410 carrying the first part 431 and the second part 432 moves and contacts the material A in the support device 480, and solidifies the material A to form the third part 433.

[0090] Understandably, the cleaning frequency is settable. In some embodiments, before the molding platform 410 leaves the support device 480 and approaches the support device 490, the molding platform 410 moves to a cleaning position to allow the cleaning unit 470 to clean the uncured material; before the molding platform 410 leaves the support device 490 and approaches the support device 480, the molding platform 410 moves to a cleaning position to allow the cleaning unit 470 to clean the uncured material. In some embodiments, the molding platform 410 leaves the support device 480 and approaches the support device 490 to form a second portion 432, then the molding platform 410 leaves the support device 490 and approaches the support device 480 to form a third portion 433, and then, before the molding platform 410 leaves the support device 480 and approaches the support device 490, the molding platform 410 moves to a cleaning position to allow the cleaning unit 470 to clean the uncured material.

[0091] Understandably, it is necessary to clean the bottom and side surfaces of objects adhering to the forming platform (e.g., the first part 431, the second part 432, and the third part 433). The area of ​​the bottom surface to be cleaned depends on the size of the object to be printed, and the area of ​​the side surface to be cleaned depends on the size of the contact area between the object adhering to the forming platform and the container. When the liquid level in the container is high, the contact area between the side surface of the object adhering to the forming platform and the material is large, resulting in a larger area of ​​the side surface to be cleaned, which increases the difficulty of cleaning. For example, when the slice layer thickness is 50 μm, a liquid level of 1000 μm to 2000 μm (the liquid level at the bottom of container 480 is 0, and the liquid level at the surface of container 480 is 1000 μm to 2000 μm) is beneficial for performing multiple prints and then replenishing material A, but material A is attached to the side surface of the object adhering to the forming platform at a liquid level of 995 μm to 1995 μm. If the liquid level in container 480 is adjusted to 50μm to 1000μm, the area to be cleaned will shrink. To meet the requirement of constructing objects in layers, the liquid level in the container must be greater than or equal to the thickness of the current layer to be cured. For example, if the thickness of the current layer to be cured is 100μm, then the liquid level in the first container must be at least 100μm.

[0092] Figure 5 A schematic diagram of a portion of an additive manufacturing system is shown. For simplicity, optical units and some support devices are omitted. The additive manufacturing system includes a forming platform 510 on which multiple support elements 520 are adhered, and a target object is formed on the support elements 520. The target object comprises three parts 530, 540, and 550. The first part 530 is made of a first type of material A, the second part 540 is made of a first type of material A, and the third part 550 is made of a second type of material B. The first part 530 is adhered to the multiple support elements 520, and the second part 540 and the third part 550 are formed on the first part 530. A support device 560 of the additive manufacturing system accommodates the first type of material A. Figure 5 The second portion 540 and the third portion 550 shown are partially immersed in the material contained in the carrier device 560 in preparation for curing material A of a predetermined thickness.

[0093] exist Figure 5 In the illustrated embodiment, a portion of the bottom and side surfaces of the target object are in contact with material A, and these surfaces require subsequent cleaning. This is to allow material A to form a new cured layer. Figure 5The bottom surface of the target object (i.e., the bottom surfaces of the second portion 540 and the third portion 550) must be entirely in contact with material A, while only a portion of the side surface of the target object is in contact with material A. The area of ​​the side surface of the target object in contact with material A is related to the liquid level in the bearing device 560. An increased liquid level leads to an expansion of the area of ​​the side surface of the target object in contact with material A, which increases the difficulty of cleaning the target object in many scenarios. For example, the aforementioned expanded area requires the cleaning unit to have a larger working range. Alternatively or additionally, the aforementioned expanded area means that more material adheres to the side surface of the target object, and therefore, the amount of material to be removed or separated is increased.

[0094] Figure 5 The second portion 540 and the third portion 550 shown are partially immersed in the material A contained in the carrier 560. The second portion 540 has a first side portion 5410 (e.g., having a flat surface) that is in contact with the material A and is away from the third portion 550, and a second side portion 5420 (e.g., having a flat surface) that is close to the third portion 550 and in contact with the material A. The third portion 550 has a first side portion 5510 (e.g., having a flat surface) that is close to the second portion 540 and in contact with the material A, and a second side portion 5520 (e.g., having a flat surface) that is away from the second portion 540 and in contact with the material A. The second side portion 5420 of the second portion 540 and the first side portion 5510 of the third portion 550 define a slit, the width of which is the distance between the second side portion 5420 of the second portion 540 and the first side portion 5510 of the third portion 550, for example, 100 μm, 300 μm, or 500 μm. Understandably, the width and depth (or “height”) of the slits affect the removal of material adhering to the sides 5410, 5420, 5510, and 5520. However, the width of the slits is constant (constrained by the size of the target object itself), while the depth or height of the slits depends at least on the liquid level of the material carried by the bearing device.

[0095] In some examples, when using centrifugal rotation to remove material adhering to the sides, the material adhering to sides 5420 and 5510 is not easily removed due to the small width of the slit (e.g., within 2 mm), especially when the depth or height of the slit is large. Lowering the liquid level of the material carried by the carrier device helps to reduce or decrease the depth or height of the slit, thereby facilitating the removal of material adhering to the sides. It is understood that the aforementioned cleaning unit (which can be of various forms) can be used to clean the material on the sides defining the slit, and a lower liquid level facilitates the cleaning process. The liquid level is, for example, 100 μm to 1000 μm.

[0096] In some embodiments, Figure 5The slit shown is replaced with a hole, the diameter of which is, for example, 100 μm to 5000 μm.

[0097] The inventors also discovered that when the liquid level of the material carried by the support device (e.g., a container) is high, the probability of air bubbles appearing in the layer solidified at the bottom of the container is low; conversely, when the liquid level of the material in the container is low, the probability of air bubbles appearing in the layer solidified at the bottom of the container is high. The liquid level of the material in the container directly affects the immersion travel of the forming platform (and the object adhered to it), and thus affects the number of air bubbles in the layer to be solidified. Despite other factors related to air bubbles, the inventors found that, all other things being equal, a higher liquid level is beneficial in suppressing the number and / or size of air bubbles in the layer to be solidified.

[0098] The following are some printing test results.

[0099] Example 1: The liquid level is set to 1000 μm, and the thickness of the layer to be cured is 100 μm. After curing the 100 μm thick layer, the cured object on the molding platform is cleaned by bringing the cured object into contact with a cleaning mechanism (including cloth or sponge) to remove the printing material from the surface of the cured object. The cleaning effect is found to be poor after this process. After switching between a container containing white or hard material A and a container containing red or soft material B 20 times, abnormal portions caused by the mixing of materials A and B (i.e., the cured object includes completely red portions, completely white portions, and mixed-color portions) are formed in the cured object, along with multiple identifiable bubbles (number S). Mixed-color portions appear in both containers (i.e., white or hard material A is contaminated by red or soft material B, and red or soft material B is contaminated by white or hard material A).

[0100] Example 2: The liquid level is set to 400 μm, and the thickness of the layer to be cured is 100 μm. After curing the 100 μm thick layer, the cured object on the molding platform is cleaned by bringing the cured object into contact with a cleaning mechanism (including cloth or sponge) to remove the printing material from the surface of the cured object. The cleaning effect was found to be poor after this process. After switching between a container containing white or hard material A and a container containing red or soft material B 20 times, no abnormal parts formed in the cured object (i.e., the cured object does not include mixed colors), but several identifiable bubbles (approximately S in number) were formed, such as... Figure 6A As shown. No color mixing was observed in either container (i.e., white or hard material A was not contaminated by red or soft material B, and red or soft material B was not contaminated by white or hard material A).

[0101] Example 3: The liquid level is set to 200 μm, and the thickness of the layer to be cured is 100 μm. After curing the 100 μm thick layer, the cured object on the molding platform is cleaned by bringing the cured object into contact with a cleaning mechanism (including cloth or sponge) to remove the printing material from the surface of the cured object. The cleaning effect was found to be good after the treatment. After switching between a container containing white or hard material A and a container containing red or soft material B 20 times, no abnormal parts were formed in the cured object (i.e., the cured object included completely red and completely white parts), but several identifiable bubbles were formed (approximately S*130%), such as... Figure 6B As shown. There is no color mixing in either container (i.e., white or hard material A is not contaminated by red or soft material B, and red or soft material B is not contaminated by white or hard material A).

[0102] Different materials are used to form different objects in different scenarios, thus requiring different levels of control over, for example, the presence of air bubbles. For instance, with transparent or translucent materials (e.g., pink material used to create gingival models or white material used to create dental crown models), air bubbles in the cured object are easily visible to the human eye, making it particularly important to control the number of air bubbles in the cured object. Therefore, the liquid level for transparent or translucent materials is typically 200 μm to 500 μm, such as 400 μm, to obtain an object with a certain air bubble distribution density. Conversely, with opaque materials, air bubbles in the cured object may be located inside the object and are therefore less easily visible to the human eye, thus requiring less control over air bubbles. For instance, the liquid level for opaque materials is typically 50 μm to 300 μm, such as 100 μm, to facilitate related cleaning operations.

[0103] Those skilled in the art will understand that the probability of air bubbles appearing in certain types of printing materials is low, and in such cases, the design of the liquid level can disregard the risk of air bubbles. In some embodiments, defoamers or similar agents may be applied to the printing material to reduce the risk of a large number of air bubbles.

[0104] Too low a liquid level will produce bubbles and it is difficult to control the precision, while too high a liquid level will increase the difficulty of cleaning.

[0105] To avoid color mixing of materials in multiple containers, the liquid level of the material in each container should be 20μm to 1000μm, for example, 40μm to 950μm, for example, 50μm to 800μm, for example, 60μm to 700μm, for example, 70μm to 600μm, for example, 80μm to 500μm, for example, 90μm to 480μm, for example, 40μm, for example, 80μm, for example, 90μm, for example, 100μm, for example, 110μm, for example, 120μm, for example, 150μm, for example, 200μm, for example, 250μm, for example, 300μm, for example, 320μm, for example, 350μm, for example, 380μm, for example, 400μm, for example, 450μm.

[0106] For at least the construction of a single layer (or a single part) of the target object, the liquid level of the material in each container should be greater than the thickness of the layer to be cured. Considering that the thickness of the slice layer or the layer to be cured is 20 μm to 200 μm, the liquid level of the material in each container should be, for example, 20 μm to 1000 μm, 30 μm to 800 μm, 40 μm to 700 μm, 50 μm to 600 μm, 60 μm to 500 μm, 70 μm to 480 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 150 μm, 200 μm, 250 μm, 300 μm, 320 μm, 350 μm, 380 μm, 400 μm, or 450 μm. Taking a layer thickness of 50μm as an example, the liquid level can be 50μm to 1000μm, 60μm to 950μm, 75μm to 700μm, 100μm to 600μm, 200μm to 500μm, or 300μm to 400μm. The liquid level can be 1 to 20 times the thickness of the layer to be cured, for example, 1.5 to 18 times, 2 to 8 times, 3 to 7 times, 4 to 6 times, 1.2 times, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times, 2.5 times, 2.6 times, 2.7 times, 2.8 times, 2.9 times, 3.0 times, 3.1 times, etc. 3.2 times, for example 3.3 times, for example 3.4 times, for example 3.5 times, for example 3.6 times, for example 3.7 times, for example 3.8 times, for example 3.9 times, for example 4.0 times, for example 4.1 times, for example 4.2 times, for example 4.3 times, for example 4.4 times, for example 4.5 times, for example 4.6 times, for example 4.7 times, for example 4.8 times, for example 4.9 times, for example 5.0 times, for example 5.1 times, for example 5.2 times, for example 5.3 times, for example 5.4 times, for example 5.5 times, for example 5.6 times, for example 5.7 times, for example 5.8 times, for example 5.9 times.

[0107] To at least reduce the number of bubbles, the liquid level of the material in each container should be 100μm to 2000μm, for example 120μm to 1000μm, for example 150μm to 900μm, for example 160μm to 800μm, for example 180μm to 700μm, for example 190μm to 600μm, for example 200μm, for example 250μm, for example 300μm, for example 350μm, for example 400μm, for example 450μm, for example 500μm, for example 550μm.

[0108] Figure 7 A schematic diagram of a portion of an additive manufacturing system is shown. The additive manufacturing system 700 includes a molding platform 710, a first container 780, and a second container 790. Both the first container 780 and the second container 790 are box-shaped. The first container 780 contains material A, and the second container 790 contains material B, which is different from material A. To ensure that the liquid level of the material in the containers is maintained at a predetermined value or a predetermined range (e.g., 100 μm to 2000 μm, 100 μm to 8000 μm), a material supply unit is provided. The material supply unit 730 supplies material A to the first container 780, for example, through a channel or pipe 740. In some embodiments, the channel or pipe 740 is omitted. The material supply unit 750 supplies material B to the second container 790, for example, through a channel or pipe 760. In some embodiments, the channel or pipe 760 is omitted. In some embodiments, the first container 780 and the second container 790 are each equipped with a sensor for detecting the liquid level.

[0109] Figure 8 A schematic diagram of a portion of an additive manufacturing system is shown. The additive manufacturing system 800 includes a forming platform, a first container 880, and a second container 890. Both the first container 880 and the second container 890 are box-shaped. The first container 880 contains material A, and the second container 890 contains material B, which is different from material A. A material supply unit 830 supplies material A to the first container 880, and a leveling unit 810 is movable on a horizontal plane to make the liquid level in the first container 880 uniform. A material supply unit 850 supplies material B to the second container 890, and a leveling unit 820 is movable on a horizontal plane to make the liquid level in the second container 890 uniform.

[0110] Leveling unit 810 and leveling unit 820 move on the same or different horizontal planes. For example, leveling unit 810 moves such that the liquid level of the material in the first container 880 is maintained at approximately 1800 μm, while leveling unit 820 moves such that the liquid level of the material in the second container 890 is maintained at approximately 1800 μm or 2200 μm. The term "horizontal plane" here refers to a plane perpendicular to the Z-axis direction. The movement of leveling unit 810 and leveling unit 820 includes any of the following: translation, rotation, and pivoting. For example, Figure 8 The arrow in the image indicates the direction of translation.

[0111] exist Figure 8 In the illustrated embodiment, leveling unit 810 is used to ensure a uniform liquid surface 882, the liquid level of which is, for example, 2000 μm. Leveling unit 820 is used to ensure a uniform liquid surface 892, the liquid level of which is, for example, 500 μm.

[0112] Figure 9Examples of methods for maintaining printing liquid levels are shown. For example... Figure 9 As shown, the material supply device 920 supplies material to the container 950 at a supply position designed close to the sidewall of the container 950. The continuous or intermittent application of material results in a higher liquid level in the container 950 at the supply position. A level holding device 910 undergoes planar movement (e.g., translation or rotation) between a first position 942 and a second position 944, resulting in a uniform liquid level in the region of the container 950 between the first position 942 and the second position 944. The bottom surface of the level holding device 910 is configured to maintain a predetermined distance from the bottom (e.g., membrane) of the container 950, and the level holding device 910, for example, has no through-holes allowing material to pass through. Through the planar movement of the level holding device 910, the liquid level in a portion of the container 950 (e.g., the region between the first position 942 and the second position 944) is equal to the aforementioned predetermined distance, while the liquid level in the container 950 at the supply position is higher than the aforementioned predetermined distance. For example, the liquid level 952 of container 950 in the region between the first position 942 and the second position 944 is 300 μm, and the liquid level 951 of container 950 at the supply position is 700 μm.

[0113] A material supply device 930 may also be provided to supply material to container 950 from another supply location. Material supply devices 920 and 930 supply material to container 950, and a liquid level holding device 910 translates between a first position 942 and a second position 944, such that the liquid level 951 at the first supply position and the liquid level 953 at the second supply position are higher than the liquid level 952 of the target area. The target area is, for example, the area between the first position 942 and the second position 944. During printing, the cured material is located in the target area.

[0114] Figure 10 Examples of methods for maintaining printing liquid levels are shown. For example... Figure 10 As shown, the additive manufacturing system includes a container 1050 and a liquid level holding device 1010. The liquid level holding device 1010 is provided with a material channel 1012 and at least one opening 1014 in fluid communication with the material channel 1012. The material channel 1012 of the liquid level holding device 1010 is connected to a material supply device (not shown), such that the material supply device supplies material to the container 1050 via the material channel 1012 and at least one opening 1014. The liquid level holding device 1010 moves on a horizontal plane and is capable of delivering material to the container during movement to maintain the liquid level in the container 1050 substantially at a predetermined value or within a predetermined range. Figure 10 The material channel 1012 shown is formed by machining or molding. In other embodiments, the material channel is in the form of a pipe and is located outside the liquid level holding device.

[0115] Figure 11 Examples of methods for maintaining printing liquid levels are shown. For example... Figure 11 As shown, the additive manufacturing system includes a plate-shaped support device 1150 and a liquid level holding device 1110. Compared to a box-shaped support device (or container), the plate-shaped support device does not have sidewalls for containing material. Figure 11 The plate-shaped support device 1150 shown includes a membrane and a clamping assembly for holding the membrane.

[0116] The level holding device 1110 is provided with a material channel 1112 and at least one opening 1114 in fluid communication with the material channel 1112. The material channel 1112 of the level holding device 1110 is connected to a material supply device (not shown) such that the material supply device supplies material to the plate-shaped support device 1150 via the material channel 1112 and at least one opening 1114. The level holding device 1110 moves on a horizontal plane and is capable of delivering material to the container during movement to maintain the liquid level 1152 on the plate-shaped support device 1150 substantially at a predetermined value or within a predetermined range. It is understood that the material applied to the membrane by the level holding device 1110 does not have a uniform liquid level over the entire area of ​​the membrane, but only a uniform liquid level in a portion of the membrane (e.g., the central region). The amount of material applied by the level holding device 1110, the properties of the material, and the associated process parameters do not allow material to leave the plate-shaped support device 1150 (which could lead to contamination of the equipment).

[0117] Figure 12 Examples of methods for maintaining printing liquid levels are shown. For example... Figure 12As shown, the additive manufacturing system includes a plate-shaped support device 1250, a material supply device 1230, and a liquid level holding device 1210. The material supply device 1230 is, for example, in the form of a nozzle. The material supply device 1230 and the plate-shaped support device 1250 are movable relative to each other, such that the material supply device 1230 can supply material to any position on the plate-shaped support device 1250. After the material supply device 1230 supplies material to the plate-shaped support device 1250, the liquid level holding device 1210 is movable in a horizontal plane to flatten and hold the material on the support device 1250 at a predetermined height (or referred to as a “predetermined liquid level” 1252). In some embodiments, the material supply device 1230 is movable relative to the plate-shaped support device 1250, such that the material supply device 1230 allows material to be supplied to a desired position on the support device 1250, and then the liquid level holding device 1210 moves to flatten the material and hold it at the predetermined height. In some embodiments, the liquid level holding device 1210 is omitted, the material supply device 1230 is movable relative to the plate-shaped support device 1250, and the material supply device 1230 supplies material to multiple locations on the support device 1250, whereby the supplied material flows naturally.

[0118] Figure 13 Examples of methods for maintaining printing liquid levels are shown. For example... Figure 13 As shown, the additive manufacturing system includes a carrier 1350, a material supply device 1330, and a liquid level holding device 1310. At least one material supply device 1330 supplies material to the carrier 1350, and then the liquid level holding device 1310 moves on a horizontal plane to flatten the material and hold it at a predetermined height. Figure 13 The carrying device 1350 shown includes a collection container 1354, into which excess material pushed by the liquid level holding device 1310 will fall at position K1. Figure 13 The carrying device 1350 shown may also include a collection container 1356, into which excess material pushed by the liquid level holding device 1310 will fall at position K2. Figure 13 The carrier device 1350 shown is an integral unit.

[0119] Figure 14 Examples of methods for maintaining printing liquid levels are shown. For example... Figure 14As shown, the additive manufacturing system includes a support device 1450, a material supply device 1430, a liquid level holding device 1410, and at least one collection container 1470, 1480. At least one material supply device 1430 supplies material to the plate-shaped support device 1450, and then the liquid level holding device 1410 moves on a horizontal plane to flatten the material and hold it at a predetermined height. Excess material pushed by the liquid level holding device 1410 falls into the collection container 1470 at position K1, and excess material pushed by the liquid level holding device 1410 falls into the collection container 1480 at position K2. It is understood that... Figure 14 The carrying device 1450 shown is separate from the collection containers 1470 and 1480.

[0120] Figures 15A-15C Examples of methods for maintaining printing liquid levels are shown. For example... Figure 15A As shown, the additive manufacturing system includes a box-shaped carrier 1550, a material supply device 1530, and a liquid level holding device 1510. Some components of the additive manufacturing system (e.g., optical units and forming platforms) are concealed. The liquid level holding device 1510 is movable toward or away from the carrier 1550, for example, along the Z-direction. The liquid level holding device 1510 is movable in a horizontal plane perpendicular to the Z-direction, for example, translating along the X-direction perpendicular to the Z-direction, or rotating in a direction perpendicular to the Z-direction. For example, through the material supply from the material supply device 1530 and the translation of the liquid level holding device 1510 along the X-direction, the liquid level of the material in the carrier 1550 is h1 (referring to the liquid level of the material in the area subsequently exposed). h1 is, for example, 200 μm to 1000 μm, for example, 300 μm to 700 μm. When using two or more materials to cure and form an object, the liquid level h1 at least helps to reduce the difficulty of cleaning (e.g., see reference). Figure 5 (Example shown).

[0121] Figure 15BA liquid level holding device 1510 at another height is shown. The additive manufacturing system also includes a drive mechanism (not shown) for driving the liquid level holding device 1510 to move in the Z direction. The drive mechanism drives the liquid level holding device 1510 to move in the Z direction closer to the carrier device 1550, and then the liquid level holding device 1510 translates in the X direction to make the liquid level of the material in the carrier device 1550 h2 (referring to the liquid level of the material in the area to be subsequently exposed). h2 is, for example, 50 μm to 500 μm, for example, 100 μm to 200 μm. It is understood that when it is necessary to cure the material at a liquid level h1, the liquid level holding device 1510 is first used to maintain the liquid level h2 (less than h1), and then the liquid level holding device 1510 is raised and the liquid level h1 is maintained in preparation for curing. A liquid level h2 lower than the liquid level h1 is at least beneficial to reducing the number of air bubbles in the material, and therefore beneficial to ensuring the quality of the object formed at the liquid level h1.

[0122] Figure 15C A liquid level holding device 1510 at another height is shown. A drive mechanism moves the liquid level holding device 1510 away from the carrier device 1550 in the Z direction, and then the liquid level holding device 1510 translates in the X direction to make the liquid level of the material in the carrier device 1550 h3 (referring to the liquid level of the material in the area subsequently exposed). h3 is, for example, 800 μm to 3000 μm, for example, 1000 μm to 2000 μm. It is understood that for some objects, a portion of the layers involves at least two materials, while the remaining layers of these objects involve only a single material (e.g., see reference...). Figure 1 (Layers 131, 132, and 133). When multiple layers are continuously formed from a single material, the cleaning step of the formed object can be omitted, and the liquid level can be increased. Curing at a liquid level h3 above the liquid level h1 is beneficial at least in reducing the number of air bubbles in the material, and thus in ensuring the quality of the formed object.

[0123] Figures 15A-15C The illustrated level holding device 1510 can remain at any distance from the membrane of the carrier device 1550, for example, 0 to 8000 μm. To ensure accuracy, for example, along the Z-direction, the level holding device can be equipped with a detection element such as a height sensor. The level holding device 1510 can contact the membrane of the carrier device 1550, which at least facilitates the calibration of the height positioning of the level holding device 1510 based on a force sensor. The level holding device 1510 can even press down on the membrane of the carrier device 1550 along the Z-direction (e.g., causing a portion of the horizontal membrane to be recessed by 20 μm) and move horizontally along the X-direction, which at least facilitates cleaning, collecting, or gathering material on the membrane of the carrier device 1550.

[0124] Figure 9-14 and Figures 15A-15C Only the configuration of a single carrier is shown; at least two carriers for an additive manufacturing system can be configured in the same or similar manner.

[0125] Figures 16A-16D Examples of cleaning units are shown. The additive manufacturing system includes a molding platform 1610 on which an object 1630 composed of two materials is adhered. Before the next material curing, the molding platform 1610 moves to a cleaning position to clean the formed object 1630.

[0126] Figure 16A The cleaning unit shown includes a base 1678 and an absorbent layer 1672, which is in the form of, for example, cloth or sponge, and is capable of at least partially absorbing liquid or paste-like materials adhering to the object 1630 when the object 1630 comes into contact with the absorbent layer 1672. For example, the molding platform 1610 carrying the object 1630 along... Figure 16A As the arrow points in the direction shown, the object 1630 moves closer to and contacts (or even presses down) the absorbent layer 1672, allowing liquid material on the object 1630 to enter the micropores of the absorbent layer 1672 (i.e., be absorbed). It is understood that the absorbent layer 1672 can be held or secured to the base 1678 in various ways, such as by tethers, screws, tape, etc. In some embodiments, the absorbent layer 1672 is removable and / or replaceable. In some embodiments, the thickness of the absorbent layer 1672 is designed based on requirements, for example, 3cm to 20cm, or 5cm to 10cm. It is understood that the absorbent layer directly absorbs the resin, avoiding the possibility of introducing new material into the cured object compared to using cleaning agents (such as water or alcohol). Therefore, the absorbent layer 1672 has a wider range of applications. In some embodiments, the absorbent layer is made of a soft, porous material, meaning that when the molding platform (carrying the cured object) presses down on the soft, porous material, a portion of the side of the cured object near the absorbent layer and the bottom surface come into contact with the soft, porous material, thereby absorbing any uncured resin adhering to it. In some embodiments, this soft, porous material is used in conjunction with the multiple height-switchable liquid level holding mechanisms described above, such that uncured resin adheres to only a portion of the side of the cured object near the absorbent layer, and is subsequently removed by the soft, porous material that covers and contacts the resin.

[0127] In some embodiments, the base 1678 is movable (e.g., movable toward the molding platform). The driver used to drive the base 1678 and / or other components is, for example, a stepper motor, servo motor, linear motor, DC motor, cylinder, or hydraulic rod. In some embodiments, the driver is equipped with a transmission mechanism, such as a belt, timing belt, gear, lead screw, cam, or connecting rod.

[0128] Figure 16B The cleaning unit shown includes a base 1678, a first absorbent layer 1672, and a second absorbent layer 1674. The first absorbent layer 1672 and the second absorbent layer 1674 are made of different materials, for example. For instance, the first absorbent layer 1672 may include fabric, and the second absorbent layer 1674 may include a sponge. When the forming platform 1610 carrying the object 1630 moves along... Figure 16B As the object 1630 moves toward and contacts (or even presses down on) the first absorbent layer 1672 in the direction of the arrow shown, the liquid material on the object 1630 enters the micropores of the absorbent layer 1672 (i.e., is absorbed). In some embodiments, the cleaning unit includes at least one first absorbent layer 1672 and / or at least one second absorbent layer 1674.

[0129] Figure 16C The cleaning unit shown includes a base 1678, a first absorption layer 1672, a second absorption layer 1674, and a heating element 1676. The heating element 1676 is used to raise the temperature of the first absorption layer 1672 and / or the second absorption layer 1674, at least causing a change in the viscosity of the liquid material absorbed by the first absorption layer 1672 and / or the second absorption layer 1674, thereby facilitating absorption by the absorption layers. It can be understood that in some scenarios, a portion of the heat generated by the heating element 1676 is transferred to the uncured liquid material on the object 1630; the increased temperature lowers the viscosity of the liquid material, thus facilitating absorption by the absorption layers. The heating element 1676 allows the absorption layers to be heated to a specified temperature or a specified temperature range. The aforementioned specified temperature or specified temperature range is related to the viscosity-temperature relationship of the liquid material. The heating element 1676 is, for example, a PTC heating element.

[0130] Figure 16D The cleaning unit shown includes a base 1678, a first absorbent layer 1672, a second absorbent layer 1674, and a negative pressure assembly 1676. The negative pressure assembly 1676 provides negative pressure to the first absorbent layer 1672 and / or the second absorbent layer 1674, allowing air to pass through the first and second absorbent layers 1672 and enter the negative pressure assembly 1676. It is understood that the negative pressure assembly 1676 facilitates the flow of liquid material from the object 1630 within the first and second absorbent layers 1672 and 1674 (i.e., improving cleaning efficiency). In some embodiments, the negative pressure assembly 1676 also collects liquid material flowing through the first and second absorbent layers 1672 and 1674. The negative pressure assembly 1676 is mounted, for example, such that the absorbent layers 1672 and 1674 are arranged between the object 1630 and the negative pressure assembly 1676. The negative pressure component can be in the form of a vacuum pump, which includes at least one of the following: rotary vane pump, reciprocating pump, water ring pump, dry screw vacuum pump, slide valve pump, Roots pump, and diffusion pump.

[0131] exist Figure 16DIn a variant of the illustrated embodiment, the negative pressure component is replaced with a positive pressure component. For example, at least one positive pressure component applies an airflow to the object 1630 to blow off any uncured liquid material thereon, and this at least one positive pressure component also applies an airflow to the absorbent layers to facilitate the flow of liquid material from the object 1630 through the first absorbent layer 1672 and the second absorbent layer 1674 (i.e., improving cleaning efficiency). Additionally, a separate container may be provided to collect the liquid material flowing through the first absorbent layer 1672 and the second absorbent layer 1674.

[0132] It is understood that the cleaning unit may include at least one of the aforementioned absorbent layer, negative pressure assembly, heating element, or positive pressure assembly. These components or assemblies work on liquid materials or absorbent layers on objects.

[0133] Figures 17A-17D A portion of an additive manufacturing system according to some embodiments is shown. Figure 17A As shown, the additive manufacturing system includes a liquid level holding device (or actuator) 1710 and a carrier unit 1730. Schematably, the carrier unit 1730 includes three carrier devices 1731, 1732, and 1733, each carrying a different material. For example, the first carrier device 1731 holds a gray resin material M1, the second carrier device 1732 holds a blue resin material M2, and the third carrier device 1733 holds a transparent resin material M3. Correspondingly, the actuator 1710 includes three leveling components 1714, 1716, and 1718. The first leveling component 1714 maintains at least a portion of the material M1 carried by the first carrier device 1731 at a predetermined liquid level, for example, 200 μm. The second leveling component 1716 maintains at least a portion of the material M2 carried by the second carrier device 1732 at the same predetermined liquid level, for example, 200 μm. The third leveling component 1716 enables at least a portion of the material M3 carried by the third bearing device 1733 to be maintained at the same predetermined liquid level, for example, 200 μm.

[0134] exist Figures 17A-17D In the illustrated embodiment, the actuator 1710 further includes a connector 1712 to which three leveling components 1714, 1716, and 1718 are connected or fixed, allowing the three leveling components to move synchronously (e.g., synchronously raise or synchronously translate). It will be understood that in other embodiments, the three leveling components move independently, for example, via a connecting rod for each leveling component, which is driven by a drive mechanism. For example, upon receiving a signal, only a single leveling component is controlled to raise or translate.

[0135] Both the actuator 1710 and the carrier unit 1730 are located on the support assembly 1750 and can move together with the support assembly 1750 (e.g., translate along the direction in which the three carriers are arranged). For example, after material M1 carried by the first carrier 1731 has been cured, material M3 carried by the third carrier 1733 will be cured. At this time, a first drive mechanism (e.g., an electric motor, not shown) drives the support assembly 1750 and the actuator 1710 and carrier unit 1730 thereon to translate together, so that the optical unit, the third carrier 1733, and the forming platform of the additive manufacturing system are aligned. After alignment, a second drive mechanism drives the forming platform to move in preparation for the subsequent curing step.

[0136] Figure 17A and Figure 17B The actuators are shown in different positions. For example, if the direction in which the three support devices are arranged is defined as the first direction, then the actuator 1710 can move along a second direction perpendicular to the first direction from... Figure 17A The indicated position moves to Figure 17B The location shown. Figure 17A and Figure 17B Three leveling components for synchronized movement of the actuator are shown. In other embodiments, at least one of the three leveling components is independently driven and capable of movement along the aforementioned second direction. In other embodiments, one of the three leveling components is independently driven and capable of movement along the aforementioned first direction (this requires changing the arrangement orientation of the leveling components, for example, arranging a single leveling component to extend along the second direction).

[0137] Figure 17C A lifting mechanism for the actuator is shown. The lifting mechanism 1720 is capable of driving the actuator 1710 to move along a third direction (Z direction), which is perpendicular to the first and second directions. The lifting mechanism 1720 allows the actuator 1710 to remain at different horizontal heights, and the different heights of the actuator 1710 (or leveling member) allow the material carried by the support device to be maintained at different liquid levels or heights. For example, the first leveling member 1714 of the actuator 1710 translates along the second direction, causing at least a portion of the material M1 carried by the first support device 1731 to be maintained at a predetermined liquid level, for example, 200 μm. Then, the lifting mechanism 1720 drives the actuator 1710 to rise, and the second leveling member 1716 translates along the second direction, causing at least a portion of the material M2 carried by the second support device 1732 to be maintained at another predetermined liquid level, for example, 400 μm. Then, the third leveling member 1716 translates along the second direction, causing at least a portion of the material M3 carried by the third support device 1733 to be maintained at yet another predetermined liquid level, for example, 1000 μm.

[0138] Figure 17CIn this design, the lifting mechanism 1720 includes a drive mechanism (e.g., an electric motor or cylinder) 1722 and an optional flange element 1724. The lifting mechanism 1720 is connected to at least one support rod 1711, 1713 of the actuator 1710, which is raised or lowered as the drive mechanism 1722 operates. Figure 17C Only a portion of the lifting mechanism 1720 and the actuator 1710 is shown.

[0139] Figure 17D A single leveling component is shown. The leveling component 1714 includes a connecting portion 17142 for connection with a connector 1712, and a body portion 17144 for at least maintaining a predetermined liquid level. In some embodiments, the connecting portion 17142 is omitted, and the body portion 17144 is integrally formed with the connector 1712. In some embodiments, the leveling component 1714 also includes a mating hole 17143, for example, in the form of a threaded hole, which facilitates further reinforcement of the connection between the leveling component 1714 and the connector 1712 by conventional fasteners (e.g., screws).

[0140] In some embodiments, the leveling member 1714 includes at least one through-hole 17146, which is disposed in the upper portion of the leveling member 1714, for example, within 20% to 95% of the height of the leveling member, for example, within 30% to 80% of the height of the leveling member, for example, within 40% to 75% of the height of the leveling member. This allows excess material applied to the support device to overflow from one side of the leveling member 1714 to the opposite side via the through-hole 17146. Correspondingly, the lower portion of the leveling member does not allow material to flow through it.

[0141] It is understandable that the function of the leveling component is at least to maintain a preset liquid level, but the specific implementation is influenced by other factors. In some scenarios, a predetermined amount of material is supplied in a box-type support device. After the material naturally levels, the average liquid level of the entire material area is 600 μm. To achieve the desired liquid level of 400 μm, the leveling component is driven to move to a height of 400 μm from the support device, and then moves (translation or rotation, e.g., reciprocating) on ​​a horizontal plane so that the liquid level in a portion of the material area (e.g., the middle portion) is essentially maintained at 400 μm, while the liquid level in the remaining portion of the material area (e.g., the two sides surrounding the middle portion) is higher than 600 μm. During this process, no material flows through the leveling component (regardless of whether the leveling component has through holes 17146), and material above 400 μm is pushed and temporarily accumulated in the undesirable area (e.g., the two sides). Due to the natural leveling of the material, the temporarily accumulated higher material (above 600 μm) tends to flow towards the lower material region (400 μm), but the higher material only flows to the desired region after a predetermined time period (e.g., 5 s to 30 s, depending at least on the material viscosity and the size of the support device). While the higher material has not flowed to the desired region, a portion of the material in the desired region is exposed and cured according to a predetermined pattern.

[0142] In other scenarios, a predetermined amount of material is supplied to a box-type support device, and after the material naturally levels, the average liquid level across the entire material area is approximately 400 μm (e.g., 410 μm). To achieve the desired liquid level of 400 μm, a leveling component is driven to move to a height of 400 μm from the support device, and then moves (translation or rotation, e.g., reciprocating) on ​​a horizontal plane so that the liquid level in a portion of the material area (e.g., the middle portion) is substantially maintained at 400 μm, while the liquid level in the remaining portion of the material area (e.g., the portions surrounding the middle portion) is slightly higher than 400 μm. During this process, no material flows through the leveling component (regardless of whether the leveling component has through-holes 17146).

[0143] In other scenarios, a predetermined amount of material is supplied within a box-type support device. Without waiting for the material to level naturally, a leveling component is directly driven to a height of 400 μm from the support device, and then moves (translated or rotated, e.g., reciprocating) on ​​a horizontal plane to maintain the liquid level at approximately 400 μm in a portion of the material area (e.g., the middle section), while the liquid level in the remaining portion of the material area (e.g., the two sides surrounding the middle section) is above 400 μm. During this process, if the leveling component has through-holes 17146, the material will flow through these through-holes and overflow to the opposite side where there is no material. This facilitates replenishing material in the material-free area to subsequently maintain the predetermined liquid level.

[0144] In some embodiments, the location of the through-hole of the leveling component is designed. If the through-hole of the leveling component is located in the lower portion, for example within 5% to 20% of the height of the leveling component, the leveling component moving on the horizontal plane will allow material to move from the through-hole in the lower portion to the other side, which is not conducive to maintaining the predetermined liquid level because the pushed material cannot accumulate in the undesired area.

[0145] It is understood that the leveling component in the foregoing embodiments is capable of reciprocating motion to achieve a predetermined liquid level. The amount of material supplied to the support device, as well as the construction and movement of the leveling component, are adjustable, and these configurations work together to achieve a predetermined liquid level in the desired material region.

[0146] Figure 18 Some embodiments of a cleaning unit are shown. The cleaning unit includes a fabric source 1810 with fabric rolled up and a conveying mechanism for the fabric. The conveying mechanism includes, for example, multiple rollers 1831, 1832, 1833, 1834, 1835 (at least one of which is a drive roller) for continuously conveying the fabric to a base 1850 (or a cleaning position). The fabric is conveyed in a direction determined by… Figure 18 The arrows in the diagram indicate this. In some examples, the forming platform 1871 carries the object to be cleaned toward the base 1850 and is cleaned at the cleaning location (e.g., uncured material on the object to be cleaned is at least absorbed or adsorbed by the cloth). After at least one (e.g., one, two, ten, twenty) cleaning cycle, a new cloth needs to be replaced to maintain the cleaning effect. At this time, a conveyor mechanism is used to remove the used cloth from the cleaning location and transport a new cloth to the cleaning location for subsequent cleaning. In some embodiments, a sponge or other absorbent material is also provided on the base 1850. In some embodiments, other cleaning components are available, such as those described in reference [reference needed]. Figures 16A-16D The example shown.

[0147] The roller is a knurled roller and / or a rubber roller, wherein the knurled roller is made of one or more metals such as aluminum, steel, and copper, and the rubber roller is made of one or more plastics such as silicone rubber, butyl rubber, nitrile rubber, and polyurethane. Patterns may be applied to the surface of the knurled roller and / or the rubber roller.

[0148] In this document, unless otherwise specified, the terms "first material" and "second material" refer to different types of materials. It is understood that the terms "first material" or "second material" can refer to a material having a single component or a mixture of multiple components.

[0149] The terms "tray" or "carrying device" as used herein can be configured in a variety of ways. In some embodiments, the tray includes multiple boxes in which liquid or paste-like material is contained. In some embodiments, the tray includes multiple plate-like elements on which liquid or paste-like material is applied. In some embodiments, the tray includes at least one box and at least one plate-like element. The forming platform is sized to allow it to fall into the printing area of ​​the respective tray (e.g., box or plate-like element).

[0150] The terms “forming platform” and “tray” used herein should be understood as horizontal. In the event that a forming platform or tray is not horizontal due to manufacturing or layout errors, it also falls within the scope of protection of this application.

[0151] The various components or elements in the embodiments shown herein can be combined with each other without causing contradiction. Embodiments obtained through such combinations also fall within the scope of this document.

[0152] The description of this invention is merely exemplary in nature, and therefore, modifications that do not depart from the spirit of the invention are intended to be within its scope. Such modifications should not be considered as departing from the spirit and scope of the invention.

Claims

1. An additive manufacturing system, characterized by, comprising: a forming platform movable along a first direction; a first carrying device configured to carry a first material; a second carrying device configured to carry a second material different from the first material; an optical unit configured to project light rays to allow the first material or the second material to solidify based on a predetermined pattern; and a cleaning unit configured to separate uncured material adhered to a solidified object on the forming platform from the solidified object, wherein the cleaning unit comprises at least one absorbent layer configured to allow the uncured material to flow into pores or voids of the absorbent layer. wherein 2. The additive manufacturing system of claim 1, wherein, the at least one absorbent layer comprises a first absorbent layer and a second absorbent layer, the first absorbent layer and the second absorbent layer being composed of different porous materials. further comprising a heating element configured to elevate a temperature of the at least one absorbent layer.

3. The additive manufacturing system of claim 1, wherein, further comprising a positive pressure assembly configured to apply an air flow to blow off the uncured material on the solidified object and to facilitate the flow of the uncured material in the pores of the absorbent layer.

4. The additive manufacturing system of claim 1, wherein, further comprising a negative pressure assembly configured to force the air flow and the uncured material to flow through the at least one absorbent layer.

5. The additive manufacturing system of claim 1, wherein, wherein the positive pressure assembly or the negative pressure assembly is equipped with a collection container configured to collect the material flowing through the at least one absorbent layer.

6. The additive manufacturing system of claim 4 or 5, wherein, wherein the positive pressure assembly or the negative pressure assembly is directly connected with the collection container.

7. The additive manufacturing system of claim 6, wherein, wherein the absorbent layer is detachable or replaceable.

8. The additive manufacturing system of claim 1, wherein, wherein the cleaning unit further comprises a wiping assembly configured to remove the uncured material by relative movement with the solidified object.

9. The additive manufacturing system of claim 1, wherein, wherein the cleaning unit further comprises a washing container configured to contain a washing agent.

10. The additive manufacturing system of claim 1, wherein, wherein the cleaning unit further comprises a spraying assembly configured to spray out a liquid to flush away the uncured material.

11. The additive manufacturing system of claim 1, wherein, wherein the absorbent layer is made of a soft porous material.

12. The additive manufacturing system of claim 1, wherein, wherein the soft porous material comprises at least one of the following: polyester fiber products, bio-fiber products, polyacrylonitrile fiber products, polypropylene fibers or modified polypropylene fiber products, wood fiber products, polyether, polyvinyl alcohol, and polyurethane.

13. The additive manufacturing system of claim 12, wherein, further comprising a conveying mechanism for conveying the absorbent layer.

14. The additive manufacturing system of claim 1, wherein, comprising:

15. A method of additive manufacturing, characterized by, projecting light rays to solidify and adhere the first material carried by the first carrying device to the forming platform; using the cleaning unit to separate uncured material adhered to a solidified object on the forming platform from the solidified object; and projecting light rays to solidify and adhere the second material carried by the second carrying device to the forming platform. ​ ​

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