3D printing apparatus and 3D printing method

Abstract

The present application discloses a 3D printing apparatus for manufacturing a target object, comprising: a first material tank, configured to accommodate a first material; a second material tank, configured to accommodate a second material which is different from the first material; a forming platform, capable of moving along a first direction toward or away from the first material tank or the second material tank; and a cleaning apparatus, configured to drive first material attached to the target object to move to the first material tank, or drive second material attached to the target object to move to the second material tank.

Description

3D printing equipment and 3D printing methods

[0001] This application claims priority to Chinese patent application No. 202511276305.X, filed on September 8, 2025, with the Chinese Patent Office; priority to Chinese patent application No. 202511276112.4, filed on September 8, 2025, with the Chinese Patent Office; and priority to Chinese patent application No. 202411843355.7, filed on December 13, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of additive manufacturing, and more specifically, to a three-dimensional printing apparatus and a three-dimensional printing method. Background Technology

[0003] 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.

[0004] 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 other materials. Therefore, an improved additive manufacturing system is needed.

[0005] In additive manufacturing technologies that utilize light sources or radiation, there are two main systems. In one system, the molding platform is immersed in a resin-containing tank, and the light source is positioned above the molding platform, projecting light to cure the resin in the liquid surface area of ​​the tank. This system is, for example, called top-down printing. In the other system, the resin-containing tank is arranged between the molding platform and the light source, which projects light to cure the resin in the transparent bottom area of ​​the tank. This system is, for example, called bottom-up printing.

[0006] Document CN116118181A discloses a downward projection printing system using multiple material tanks. The molding platform switches between different material tanks containing different materials to obtain objects composed of multiple materials. During the switching process, the cured objects need to be cleaned. When the cured portion is removed from the resin contained in the material tank, liquid resin adheres to the cured portion. An ultrasonic cleaning device located away from the material tank is required to clean the adhered liquid resin. However, this results in the adhered resin becoming waste because the resin mixes with the cleaning liquid in the ultrasonic cleaning device.

[0007] Improving material utilization is a challenge in down-projection printing systems that use multiple feed troughs. Summary of the Invention

[0008] This application provides a 3D printing apparatus for manufacturing a target object, comprising: a first material tank configured to contain a first material; a second material tank configured to contain a second material different from the first material; a forming platform capable of moving along a first direction toward or away from the first material tank or the second material tank; and a cleaning device configured to: drive the first material attached to the target object to move to the first material tank; or drive the second material attached to the target object to move to the second material tank.

[0009] In some embodiments, the cleaning device is configured to: drive a first material attached to a target object to move to the first material tank when the molding platform is aligned with the first material tank; or drive a second material attached to a target object to move to the second material tank when the molding platform is aligned with the second material tank.

[0010] In some embodiments, the cleaning device includes at least one of the following: a scraping assembly configured to move relative to a first material or a second material attached to a target object to separate the attached first material or the second material from the target object; a positive pressure airflow assembly configured to apply a positive pressure airflow to the first material or the second material attached to the target object; or a negative pressure airflow assembly configured to apply a negative pressure airflow to the first material or the second material attached to the target object to allow the first material or the second material to flow through a conduit of the negative pressure airflow assembly to a first trough or a second trough.

[0011] In some embodiments, the scraping component is configured to: maintain contact with the outer surface of the target object while moving relative to the target object; or maintain a distance of 0.001 mm to 2.000 mm from the outer surface of the target object while moving relative to the target object.

[0012] In some embodiments, the scraping assembly includes a cleaning element capable of rotating about a predetermined axis perpendicular to a first direction.

[0013] In some embodiments, the cleaning element of the scraping assembly is movable along a second direction, which is perpendicular to the first direction and the predetermined axis.

[0014] In some embodiments, the scraping assembly further includes a transfer element configured to move relative to the cleaning element to remove a first or second material adhering to the cleaning element.

[0015] In some embodiments, the transfer element is configured such that it is spaced from the outer surface of the cleaning element by 0.000 mm to 2.000 mm; spaced from the outer surface of the cleaning element by 2.001 mm to 5.000 mm; or in contact with the outer surface of the cleaning element, and one of the transfer element and the cleaning element is pressed down by the other by 0.000 mm to 10.000 mm.

[0016] In some embodiments, the scraping assembly includes a cleaning element capable of moving in a second direction perpendicular to the first direction, the cleaning element including at least one of a scraper or a brush.

[0017] In some embodiments, the scraping assembly includes an inner layer and a resilient outer layer.

[0018] In some embodiments, the material of the elastic outer layer includes at least one of the following: thermoplastic elastomer, silicone, rubber, foam, sponge, polypropylene, and nylon.

[0019] In some embodiments, the 3D printing apparatus further includes a drive mechanism configured to move at least one of the following: a first material trough, a second material trough, a forming platform, and a cleaning device.

[0020] In some embodiments, the 3D printing apparatus further includes a level maintaining device for defining the level of a first material in a first tank, a cleaning device being mounted to the level maintaining device, and the level maintaining device being movable in a second direction perpendicular to the first direction.

[0021] In some embodiments, the cleaning device includes a first cleaning element and a second cleaning element, wherein the first cleaning element is configured to move a first material attached to a target object to a first feed trough, and the second cleaning element is configured to move a second material attached to the target object to a second feed trough.

[0022] In some embodiments, the first cleaning element and the second cleaning element are driven independently or synchronously.

[0023] In some embodiments, the 3D printing apparatus further includes an auxiliary cleaning device configured to continue cleaning the first or second material of the target object after the cleaning device removes the first or second material attached to the target object.

[0024] In some embodiments, the auxiliary cleaning device is configured to separate uncured material adhering to a target object from the target object, wherein the cleaning unit includes at least one absorbent layer configured to allow uncured material to flow into the pores or pores of the absorbent layer.

[0025] In some embodiments, the 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.

[0026] In some embodiments, the 3D printing apparatus further includes a heating element configured to raise the temperature of at least one absorption layer.

[0027] In some embodiments, the 3D printing apparatus further includes a positive pressure component configured to apply an airflow to blow uncured material off a target object and configured to facilitate the flow of uncured material in the pores of the absorbent layer.

[0028] In some embodiments, the 3D printing apparatus further includes a negative pressure assembly configured to force airflow and uncured material to flow through at least one absorbent layer.

[0029] In some embodiments, the positive or negative pressure component is equipped with a collection container configured to collect material flowing through at least one absorbent layer.

[0030] In some embodiments, the auxiliary cleaning device further includes a cleaning container configured to hold a cleaning agent.

[0031] In some embodiments, the 3D printing equipment further includes a delivery mechanism for delivering the absorbent layer.

[0032] In some embodiments, the 3D printing apparatus further includes: a substrate configured to support a first material tank and a second material tank, and movable to change the position of the first material tank and the second material tank; an optical component configured to project light onto the first material tank or the second material tank; and a protective device connected to the substrate and the optical component, and including an adjustment portion formed of a flexible material.

[0033] In some embodiments, the 3D printing apparatus has: a first state in which a first material tank is aligned with an optical component; and a second state in which a second material tank is aligned with an optical component.

[0034] In some embodiments, the adjustment portion of the protective device includes a first side and an opposing second side, wherein during the transition of the 3D printing device from a first state to a second state, the first side of the adjustment portion tends to tighten, while the second side of the adjustment portion tends to loosen.

[0035] In some embodiments, the protective device has a first end for connecting a substrate and a second end for connecting an optical component, the first end being sealed to a stationary optical component and the second end being sealed to a movable substrate.

[0036] In some embodiments, the protective device includes a first portion close to the substrate and a second portion away from the substrate, the second portion including an adjustment portion, wherein the first portion includes: a rigid portion formed of a rigid material; or a flexible portion formed of a flexible material.

[0037] In some embodiments, the flexible material includes at least one of the following: natural rubber, silicone rubber, silicone leather, nylon, polyester film, and rubber.

[0038] In some embodiments, the 3D printing apparatus also includes a baffle connected to the optical components, the baffle being surrounded by a protective device.

[0039] In some embodiments, the predetermined direction includes: a linear direction, wherein the first material trough and the second material trough are spaced apart along a linear direction; or a rotational direction, wherein the first material trough and the second material trough are spaced apart along a rotational direction.

[0040] In some embodiments, the optical component includes a DLP optical engine; or the optical component includes a light source, and a first feed tank is equipped with a first LCD projection module aligned with the first feed tank, and a second feed tank is equipped with an LCD projection module aligned with the second feed tank; or the optical component includes a light source, and a first feed tank is equipped with a first LCOS projection module aligned with the first feed tank, and a second feed tank is equipped with an LCOS projection module aligned with the second feed tank.

[0041] This application also provides a 3D printing apparatus for manufacturing a target object, comprising: a first material tank configured to contain a first material; a second material tank configured to contain a second material different from the first material; a forming platform capable of moving along a first direction toward or away from the first material tank or the second material tank; and a cleaning device configured to: drive the first material attached to the target object to move to a first recycling container; and / or drive the second material attached to the target object to move to a second recycling container.

[0042] In some embodiments, the first recycling container is a first trough, and the second recycling container is a second trough.

[0043] In some embodiments, the first recycling container is spaced apart from the first trough, and the second recycling container is spaced apart from the second trough.

[0044] This application also provides a method for forming a target object by additive manufacturing, characterized in that it includes: projecting light through an optical unit to form a first solidified layer of the target object from a first material in a first material tank; moving the first solidified layer away from the first material tank through a driving device; driving the first material attached to the target object to move to a first recycling container through a cleaning device; and projecting light through an optical unit to form a second solidified layer of the target object from a second material in a second material tank.

[0045] In some embodiments, the first recycling container is a first trough; or the first recycling container is spaced apart from the first trough.

[0046] In some embodiments, the aforementioned method further includes: after driving the first material attached to the target object to move to the first recycling container, cleaning the remaining first material attached to the target object by an auxiliary cleaning device.

[0047] 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.

[0048] This application also provides a 3D printing method, which includes: aligning a first material tank and an optical component, including: moving a substrate to align the first material tank mounted on the substrate with the optical component; projecting light through the optical component onto the first material tank; and aligning a second material tank and an optical component, including: moving the substrate to align the second material tank mounted on the substrate with the optical component, wherein during the alignment of the second material tank and the optical component, the relaxation state of an adjustment portion formed of a flexible material of a protective device changes, wherein the protective device is connected to the substrate and the optical component. Attached Figure Description

[0049] 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.

[0050] Figure 1 shows a schematic diagram of a printed object including two printing materials;

[0051] Figure 2 shows a schematic diagram of a printed object including two printing materials;

[0052] Figure 3 shows the support device of the additive manufacturing system;

[0053] Figure 4 shows the cleaning unit of the additive manufacturing system;

[0054] Figure 5 shows a schematic diagram of a portion of the additive manufacturing system;

[0055] Figure 6A shows a schematic diagram of an object obtained by curing material in a container with a first liquid level;

[0056] Figure 6B shows a schematic diagram of an object obtained by curing material in a container with a second liquid level;

[0057] Figure 7 shows a schematic diagram of a portion of the additive manufacturing system;

[0058] Figure 8 shows a schematic diagram of a portion of the additive manufacturing system;

[0059] Figure 9 illustrates some embodiments for maintaining the printing liquid level;

[0060] Figure 10 illustrates some embodiments of maintaining the printing liquid level;

[0061] Figure 11 illustrates some embodiments of maintaining the printing liquid level;

[0062] Figure 12 illustrates some embodiments of maintaining the printing liquid level;

[0063] Figure 13 illustrates some embodiments of maintaining the printing liquid level;

[0064] Figure 14 illustrates some embodiments for maintaining the printing liquid level;

[0065] Figures 15A-15C illustrate some embodiments of maintaining printing liquid levels;

[0066] Figures 16A-16D illustrate some embodiments of the cleaning unit;

[0067] Figures 17A-17D illustrate a portion of an additive manufacturing system according to some embodiments;

[0068] Figure 18 illustrates some embodiments of the cleaning unit;

[0069] Figure 19 is a schematic diagram of a 3D printing device according to some embodiments of this application;

[0070] Figures 20A-20B illustrate 3D printing equipment according to some embodiments;

[0071] Figure 21 illustrates a cleaning element according to some embodiments;

[0072] Figure 22 illustrates a transfer element of a cleaning element according to some embodiments;

[0073] Figures 23A-23B illustrate 3D printing equipment according to some embodiments;

[0074] Figures 24A-24B illustrate 3D printing equipment according to some embodiments;

[0075] Figures 25A-25D illustrate 3D printing equipment according to some embodiments;

[0076] Figures 26A-26F illustrate 3D printing equipment according to some embodiments;

[0077] Figure 27 illustrates a 3D printing apparatus according to some embodiments;

[0078] Figure 28 illustrates a 3D printing apparatus according to some embodiments;

[0079] Figure 29 shows the auxiliary cleaning device for 3D printing equipment;

[0080] Figures 30A-30D are schematic diagrams of three-dimensional printing equipment according to some embodiments of this application;

[0081] Figure 31 is a schematic diagram of a 3D printing apparatus according to some other embodiments of this application.

[0082] In the accompanying drawings, some of the same or similar reference numerals represent some of the same or similar elements or components, and the scale of each part in the drawings is not necessarily true, but rather schematic. Detailed Implementation

[0083] 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.

[0084] 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.

[0085] Figure 1 shows a schematic diagram of a printed object comprising two printing materials. The 3D printing equipment or additive manufacturing system 100 includes a forming platform 110 on which the printed object is adhered. A first layer 131 of the printed object is adhered to the forming platform 110, a second layer 132 of the printed object is adhered to the first layer 131, and a third layer 133 of the printed object is adhered to the second layer 132. Layers 131, 132, and 133 of the printed object are entirely composed of material A.

[0086] A fourth layer of the printed object is adhered to the third layer 133 of the printed object. The fourth layer includes a first portion 1341 made of material A and a second portion 1342 made of material B, which is a different material 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.

[0087] A fifth layer of the printed object is adhered to the fourth layer of the printed object. The fifth layer includes 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.

[0088] A sixth layer of the printed object is adhered to the fifth layer of the printed object. The sixth layer includes 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.

[0089] In the embodiment shown in Figure 1, a first layer 131, a second layer 132, and a third layer 133 are formed first, followed by a fourth, fifth, and sixth layer. 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.

[0090] Figure 2 shows a schematic diagram of a printed object comprising two printing materials. The 3D printing equipment or additive manufacturing system 200 includes a forming platform 210 on which the printed object is adhered. A first layer 231 of the printed object is adhered to the forming platform 210, a second layer 232 of the printed object is adhered to the first layer 231, and a third layer 233 of the printed object is adhered to the second layer 232. Layers 231, 232, and 233 of the printed object are entirely composed of material A.

[0091] A fourth layer of the printed object adheres to the third layer 233 of the printed object. 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.

[0092] A fifth layer of the printed object is adhered to the fourth layer of the printed object. The fifth layer includes 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.

[0093] In the embodiment shown in Figure 2, a first layer 231, a second layer 232, and a third layer 233 are formed first, followed by a fourth and a fifth layer. The first portion 2341 of the fourth layer is formed first, followed by a second portion 2342. Similarly, the first portion 2351 of the fifth layer is formed first, followed by a second portion 2352.

[0094] 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.

[0095] Figure 3 illustrates the carrier device of an additive manufacturing system. 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, causing material A carried by carrier device 380 to solidify. The solidified 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, causing material B carried by carrier device 390 to solidify. The solidified material B adheres to the forming platform 310 and forms part 332 of the object.

[0096] 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.

[0097] 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.

[0098] Figure 4 illustrates the cleaning unit of the additive manufacturing system. 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 the stacking direction of multiple layers of the printed object. 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 the liquid or paste material A contained in the carrier device 480 in 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 rectangle, a circle, or a closed profile formed by curves.

[0099] After the cured layer 431 is formed, the molding 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).

[0100] 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 draw in uncured material adhering to the cured object.

[0101] 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.

[0102] Cleaning unit 470 includes, for example, an absorbing component. In some embodiments, the absorbing component includes a porous material, such as a sponge or cloth, which absorbs 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.

[0103] 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 containing material B to prepare for the formation of a new portion.

[0104] 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. Therefore, using the model materials as cleaning agents is appropriate.

[0105] 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.

[0106] The cleaning unit 470 includes, for example, a heating component. The heating component is used to transfer heat to uncured material attached 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 becomes more fluid and 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).

[0107] 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.

[0108] To remove uncured material adhering to a cured object, the molding platform 410 is rotatable. The molding platform 410 rotates so that the resin on the first portion 431 it carries is thrown off.

[0109] After being cleaned by cleaning unit 470, molding platform 410 carrying the first part 431 moves and contacts material B in carrier device 490, and solidifies material B to form the second part 432. Similarly, molding platform 410 leaving carrier device 490 moves to a cleaning position for cleaning by cleaning unit 470 or an additional cleaning unit. Then, molding platform 410 carrying the first part 431 and the second part 432 moves and contacts material A in carrier device 480, and solidifies material A to form the third part 433.

[0110] 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.

[0111] 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–1000μm, the area to be cleaned will decrease. To meet the requirements 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 container must be at least 100μm.

[0112] Figure 5 shows a schematic diagram of a portion of an additive manufacturing system. 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 contains the first type of material A. The second part 540 and the third part 550 shown in Figure 5 are partially immersed in the material contained in the support device 560 in preparation for curing a predetermined thickness of material A.

[0113] In the embodiment shown in Figure 5, the bottom surface and a portion of the side surfaces of the target object contact material A, which subsequently needs to be cleaned. For material A to cure and form a new cured layer, the entire bottom surface of the target object in Figure 5 (i.e., the bottom surfaces of the second portion 540 and the third portion 550) must be in contact with material A, while only a portion of the side surfaces of the target object are in contact with material A. The area of ​​the side surfaces of the target object in contact with material A is related to the liquid level in the support device 560. A higher liquid level leads to an increased area of ​​the side surfaces 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 increased area requires the cleaning unit to have a larger working range. Alternatively or additionally, the aforementioned increased area means that more material adheres to the side surfaces of the target object, thus increasing the amount of material to be removed or separated.

[0114] The second portion 540 and the third portion 550 shown in Figure 5 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 carrier device.

[0115] 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. A lower liquid level is, for example, 100 μm to 1000 μm.

[0116] In some embodiments, the slit shown in FIG5 is replaced by a hole with a diameter of, for example, 100 μm to 5000 μm.

[0117] 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 cured at the bottom of the container is low; however, when the liquid level of the material in the container is low, the probability of air bubbles appearing in the layer cured at the bottom of the container is high. The liquid level of the material in the container directly affects the immersion travel of the molding platform (and the object adhered to it), and thus affects the number of air bubbles in the layer to be cured. 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 cured.

[0118] The following are some printing test results.

[0119] 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 transparent material A and a container containing translucent material B 20 times, abnormal portions caused by the mixing of materials A and B (i.e., the cured object includes transparent, translucent, and mixed portions) are formed in the cured object, and multiple identifiable bubbles (number S) are formed. Mixed portions appear in both containers (i.e., transparent material A is contaminated by translucent material B, and translucent material B is contaminated by transparent material A).

[0120] Example 2: The liquid level was set to 400 μm, and the thickness of the layer to be cured was 100 μm. After curing the 100 μm thick layer, the cured object on the molding platform was 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 transparent material A and a container containing translucent material B 20 times, no abnormal parts were formed in the cured object (i.e., the cured object did not contain mixed parts), but several identifiable bubbles (approximately S in number) were formed, as shown in Figure 6A. No mixed parts appeared in either container (i.e., transparent material A was not contaminated by translucent material B, and translucent material B was not contaminated by transparent material A).

[0121] Example 3: The liquid level was set to 200 μm, and the thickness of the layer to be cured was 100 μm. After curing the 100 μm thick layer, the cured object on the molding platform was 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 transparent material A and a container containing translucent material B 20 times, no abnormal parts were formed in the cured object (i.e., the cured object included both translucent and transparent parts), but several identifiable bubbles were formed (approximately S*130%), as shown in Figure 6B. There was no mixing in the two containers (i.e., transparent material A was not contaminated by translucent material B, and translucent material B was not contaminated by transparent material A).

[0122] 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, resulting in less stringent requirements or restrictions on air bubbles. Therefore, the liquid level for opaque materials is typically 50 μm to 300 μm, such as 100 μm, to facilitate related cleaning operations.

[0123] 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 liquid level design 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.

[0124] 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.

[0125] To at least avoid color mixing or 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.

[0126] 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 could 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, for example, 50μm~1000μm, 60μm~950μm, 75μm~700μm, 100μm~600μm, 200μm~500μm, or 300μm~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. 0.2 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.

[0127] 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.

[0128] Figure 7 shows a schematic diagram of a portion of an additive manufacturing system. 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 within a predetermined range (e.g., 100 μm–2000 μm, 100 μm–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, for example, supplying material to the container when the liquid level is detected to have reached a threshold.

[0129] Figure 8 shows a schematic diagram of a portion of an additive manufacturing system. 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 homogenize the liquid level in the first container 880 or promote the leveling of material A in the container 880. 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 homogenize the liquid level in the second container 890 or promote the leveling of material B in the container 890.

[0130] 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, the arrow in Figure 8 indicates the direction of translation.

[0131] In the embodiment shown in FIG8, the leveling unit 810 is used to ensure at least a uniform liquid surface 882, the liquid level of which is, for example, 2000 μm. The leveling unit 820 is used to ensure a uniform liquid surface 892, the liquid level of which is, for example, 500 μm.

[0132] Figure 9 illustrates an embodiment of maintaining a printing liquid level. As shown in Figure 9, a material supply device 920 supplies material to a container 950 at a supply position designed close to the sidewall of the container 950. Continuous or intermittent material application results in a higher liquid level in the container 950 at the supply position. First positions 942 and second positions 944 are spaced apart from the sidewall of the container 950. A liquid level holding device 910 undergoes planar movement (e.g., translation or rotation) between the first and second positions 942 and 944, resulting in a uniform liquid level in the region of the container 950 between the first and second positions 942 and 944. The bottom surface of the liquid level holding device 910 is configured to maintain a predetermined distance from the bottom (e.g., membrane) of the container 950, and the liquid level holding device 910, for example, has no through-holes allowing material to pass through. Through the planar movement of the liquid level holding device 910, the liquid level in a portion of the container 950 (e.g., the region between the first and second positions 942 and 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.

[0133] 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 in container 950 are higher than the liquid level 952 in 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.

[0134] Figure 10 illustrates several embodiments of maintaining a printing liquid level. As shown in Figure 10, 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 in 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. The material channel 1012 shown in Figure 10 is formed by machining or molding, etc. In other embodiments, the material channel is in the form of a pipe and is located outside the liquid level holding device, for example, strapped to the liquid level holding device.

[0135] Figure 11 illustrates an embodiment of maintaining a printing liquid level. As shown in Figure 11, the additive manufacturing system includes a plate-shaped carrier 1150 and a liquid level holding device 1110. Compared to a box-shaped carrier (or container), the plate-shaped carrier does not have sidewalls for containing material. The plate-shaped carrier 1150 shown in Figure 11 includes a membrane and a clamping assembly for holding the membrane.

[0136] 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 in a portion of the membrane (e.g., the central region), with subsequent illumination areas in the region having a uniform liquid level. In some embodiments, the amount of material applied by the level holding device 1110, the properties of the material, and the associated process parameters prevent material from leaving the plate-shaped support device 1150 (which could lead to contamination of the equipment).

[0137] Figure 12 illustrates some embodiments of maintaining a printing liquid level. As shown in Figure 12, the additive manufacturing system includes a plate-shaped carrier 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 carrier 1250 are movable relative to each other, such that the material supply device 1230 can supply material to any position on the plate-shaped carrier 1250. After the material supply device 1230 supplies material to the plate-shaped carrier 1250, the liquid level holding device 1210 is movable in a horizontal plane to flatten and hold the material on the carrier 1250 at a predetermined height (or “predetermined liquid level” 1252). In some embodiments, the material supply device 1230 is movable relative to the plate-shaped carrier 1250, such that the material supply device 1230 allows material to be supplied to a desired position on the carrier 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.

[0138] Figure 13 illustrates an embodiment of maintaining a printing liquid level. As shown in Figure 13, 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 level the material and hold it at a predetermined height. The carrier 1350 shown in Figure 13 includes a collection container 1354 into which excess material pushed by the liquid level holding device 1310 falls at position K1. The carrier 1350 shown in Figure 13 may also include a collection container 1356 into which excess material pushed by the liquid level holding device 1310 falls at position K2. The carrier 1350 shown in Figure 13 is a single unit.

[0139] Figure 14 illustrates an embodiment of maintaining the printing liquid level. As shown in Figure 14, the additive manufacturing system includes a carrier 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 carrier 1450, and then the liquid level holding device 1410 moves horizontally to level 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 the carrier 1450 shown in Figure 14 is separate from the collection containers 1470, 1480.

[0140] Figures 15A-15C illustrate embodiments of maintaining printing liquid levels. As shown in Figure 15A, the additive manufacturing system includes a box-shaped carrier 1550, a material supply device 1530, and a liquid level holding device 1510, with some components of the additive manufacturing system (e.g., optical units and forming platforms) 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 subsequently exposed area). h1 is, for example, 200 μm to 1000 μm, or 300 μm to 700 μm. When two or more materials are used to solidify an object, the liquid level h1 at least helps to reduce the difficulty of cleaning (for example, see the example shown in Figure 5).

[0141] Figure 15B shows the liquid level holding device 1510 at another height. 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.

[0142] Figure 15C shows the liquid level holding device 1510 at another height. 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 bring the liquid level of the material in the carrier device 1550 to h3 (referring to the liquid level of the material in the area subsequently exposed). h3 is, for example, 800 μm to 3000 μm, or, for example, 1000 μm to 2000 μm. It is understood that some layers of some objects involve at least two materials, while the remaining layers of these objects involve only a single material (e.g., refer to layers 131, 132, 133 in Figure 1). When multiple layers are formed continuously with 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 at least beneficial in reducing the number of air bubbles in the material, and therefore beneficial in ensuring the quality of the formed object.

[0143] The liquid level holding device 1510 shown in Figures 15A-15C 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 liquid level holding device can be equipped with a detection element such as a height sensor. The liquid 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 liquid level holding device 1510 based on a force sensor. The liquid 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.

[0144] Figures 9-14 and 15A-15C show the configuration of only a single carrier device, but at least two carrier devices for an additive manufacturing system can be configured in the same or similar manner.

[0145] Figures 16A-16D illustrate some embodiments of the cleaning unit. The additive manufacturing system includes a forming platform 1610 on which an object 1630 composed of two materials is adhered. Before the next material curing, the forming platform 1610 moves to a cleaning position to clean the formed object 1630.

[0146] The cleaning unit shown in Figure 16A 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 material adhering to the object 1630 when it comes into contact with the absorbent layer 1672. For example, a molding platform 1610 carrying the object 1630 moves along the direction of the arrow shown in Figure 16A to approach and contact (or even press down) the absorbent layer 1672, and the liquid material on the object 1630 enters into the micropores of the absorbent layer 1672 (i.e., is absorbed). It is understood that the absorbent layer 1672 can be held or secured to the base 1678 in a variety of 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 needs, for example, 3 cm to 20 cm, or 5 cm to 10 cm. It is understandable 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 wide range of applications. In some embodiments, the absorbent layer is made of a soft porous material, which means 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 thereto. 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 only to 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 this resin.

[0147] 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.

[0148] The cleaning unit shown in Figure 16B 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, for example, made of different porous materials. For example, the first absorbent layer 1672 includes fabric, and the second absorbent layer 1674 includes a sponge. When the forming platform 1610 carrying the object 1630 moves along the direction of the arrow shown in Figure 16B to approach and contact (or even press down) the first absorbent layer 1672, 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.

[0149] The cleaning unit shown in Figure 16C 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.

[0150] The cleaning unit shown in Figure 16D includes a base 1678, a first absorption layer 1672, a second absorption layer 1674, and a negative pressure assembly 1676. The negative pressure assembly 1676 provides negative pressure to the first absorption layer 1672 and / or the second absorption layer 1674, allowing air to pass through the first and second absorption 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 absorption layers 1672 and 1674 (i.e., improving cleaning efficiency). In some embodiments, the negative pressure assembly 1676 also collects the liquid material flowing through the first and second absorption layers 1672 and 1674. The negative pressure assembly 1676 is mounted, for example, such that the absorption layers 1672 and 1674 are arranged between the object 1630 and the negative pressure assembly 1676. The negative pressure assembly can be in the form of a vacuum pump, including at least one of the following: a rotary vane pump, a reciprocating pump, and a diffusion pump.

[0151] In a variant of the embodiment shown in Figure 16D, 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.

[0152] 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.

[0153] Figures 17A-17D illustrate a portion of an additive manufacturing system according to some embodiments. As shown in Figure 17A, 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 is used to hold a gray resin material M1, the second carrier device 1732 is used to hold a blue resin material M2, and the third carrier device 1733 is used to hold a transparent resin material M3. Correspondingly, the actuator 1710 includes three leveling members 1714, 1716, and 1718. The first leveling member 1714 is capable of maintaining 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 member 1716 is capable of maintaining 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.

[0154] In the embodiments shown in Figures 17A-17D, 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 raising or synchronously translating). 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.

[0155] 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 as to align the optical unit, the third carrier 1733, and the forming platform of the additive manufacturing system. After alignment, a second drive mechanism (e.g., an electric motor, not shown) drives the forming platform to move in preparation for the subsequent curing step.

[0156] Figures 17A and 17B illustrate actuators in different positions. For example, if the direction in which the three support devices are arranged sequentially is defined as a first direction, then actuator 1710 can move from the position shown in Figure 17A to the position shown in Figure 17B along a second direction perpendicular to the first direction. Figures 17A and 17B show three leveling components moving synchronously with the actuator. In other embodiments, at least one of the three leveling components is independently driven and capable of moving along the aforementioned second direction. In other embodiments, one of the three leveling components is independently driven. In other embodiments, one leveling component can move 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).

[0157] Figures 17B and 17C illustrate a lifting mechanism for the actuator. 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 maintain 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, such as 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, such as 400 μm. Then, the third leveling component 1716 translates along the second direction, so that at least a portion of the material M3 carried by the third bearing device 1733 is maintained at another predetermined liquid level, for example, 1000 μm.

[0158] In Figure 17C, 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 shows only a portion of the lifting mechanism 1720 and the actuator 1710.

[0159] Figure 17D illustrates a single leveling component. 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 securing the connection between the leveling component 1714 and the connector 1712 using conventional fasteners (e.g., screws).

[0160] 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.

[0161] 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.

[0162] 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).

[0163] 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 moved (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 replenishment of material in areas with no or little material (attributed to the formation and departure of the previous layer) to maintain the predetermined liquid level subsequently.

[0164] 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.

[0165] 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.

[0166] Figure 18 illustrates some embodiments of the cleaning unit. 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 an active roller, such as roller 1834) for continuously conveying the fabric to a base 1850 (or a cleaning position). The direction of fabric conveying is indicated by arrows in Figure 18. In some examples, a forming platform 1870 carries the object to be cleaned toward the base 1850 and cleans it at the cleaning position (e.g., uncured material on the object to be cleaned is at least adsorbed or absorbed by the fabric). After at least one (e.g., one, two, ten, twenty) cleaning cycles, a new fabric is needed to maintain the cleaning effect. At this time, the conveying mechanism removes the used fabric from the cleaning position and conveys new fabric to the cleaning position 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 the examples shown in Figures 16A-16D.

[0167] 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.

[0168] 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.

[0169] The terms "feed tray" or "carrying device" as used herein can be configured in a variety of ways. In some embodiments, the feed tray includes multiple boxes in which liquid or paste-like material is contained. In some embodiments, the feed tray includes multiple plate-like elements on which liquid or paste-like material is applied. In some embodiments, the feed 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 corresponding feed tray (e.g., box or plate-like element).

[0170] The terms “forming platform” and “feeding trough” used herein should be understood as horizontal. In the event that the forming platform and feeding trough are not actually horizontal due to manufacturing or layout errors, they also fall within the scope of protection of this application.

[0171] Figure 19 is a schematic diagram of the structure of a 3D printing apparatus according to some embodiments of this application. The 3D printing apparatus 1900 includes a support assembly 1910 and a forming platform 1920. The support assembly 1910 includes a substrate 1911, on which a first material groove 1912 and a second material groove 1914 are provided. The first material groove 1912 is used to accommodate a first material, and the second material groove 1914 is used to accommodate a second material different from the first material. The substrate 1911 and the forming platform 1920 are movable relative to each other to adjust the position of the forming platform 1920 relative to the first material groove 1912 and the second material groove 1914.

[0172] The molding platform 1920 can move relative to the support assembly 1910 in a vertical direction or in the Z direction in FIG. 19. For example, the molding platform 1920 moves vertically closer to the first material tank 1912 to prepare for curing the first material in the first material tank 1912. Alternatively, the molding platform 1920 moves vertically away from the first material tank 1912 to separate the formed cured layer.

[0173] The 3D printing equipment 1900 includes a drive unit 1930, which drives the forming platform 1920 to move in the vertical direction.

[0174] The 3D printing equipment 1900 also includes a drive unit 1970 that moves a cleaning device relative to the forming platform 1920. The cleaning device includes cleaning elements 1942 and 1944, which are mounted to a mounting plate 1945 to allow the cleaning elements 1942 and 1944 and the mounting plate 1945 to move synchronously by the drive unit 1970, for example, along the Y direction in FIG. 19.

[0175] The cleaning elements 1942 and 1944 have a predetermined axis and are rotatable about the predetermined axis. The direction of extension of the predetermined axis is, for example, the X direction in FIG19. The 3D printing apparatus 1900 also includes a drive unit 1950, which is capable of driving the cleaning elements 1942 and 1944 to rotate along the predetermined axis.

[0176] Figures 20A-20B illustrate a 3D printing apparatus 2000 according to some embodiments. In Figure 20A, the forming platform 2020 of the 3D printing apparatus 2000 has exited the liquid in the material tank 2014, at which point the forming platform 2020 is aligned with the material tank 2014, while the cleaning device 2040 is spaced apart from the forming platform 2020. Figure 20B shows the cleaning device 2040 approaching or contacting the printed object on the forming platform 2020. A drive device 2050 is capable of driving the cleaning device 2040 to rotate about a predetermined axis, thereby removing the liquid from the printed object on the forming platform 2020.

[0177] Figure 21 illustrates a cleaning element according to some embodiments. Cleaning element 2142 is configured to move horizontally in sync with level holding device 2182, and cleaning element 2144 is configured to move horizontally in sync with level holding device 2184. The level holding device is capable of limiting the height of a portion of the material within the tank. The level holding device is, for example, the level holding device shown in Figures 17A-17D.

[0178] Figure 22 illustrates a transfer element of a cleaning element according to some embodiments. A cleaning element 2242 is mounted to a rotating shaft 2248 such that the shaft 2248 can rotate the cleaning element 2242, thereby removing unwanted liquid material by rotation when the cleaning element 2242 contacts liquid material on the printed object. A protective cover 2249 shields at least a portion of the rotating shaft 2248. The protective cover 2249 and a liquid level holding device 2282 are secured to each other by fasteners (e.g., screws). A transfer element 2246 is mounted to contact the cleaning element 2242, for example, by pressing and deforming a portion of the cleaning element 2242 by the transfer element 2246. As the cleaning element 2242 rotates, liquid material on the cleaning element 2242 is removed by the transfer element 2246.

[0179] Optionally, the transfer element 2246 is equipped with an elastic element 2247 (e.g., a spring) that provides cushioning for the transfer element 2246 and facilitates mutual movement between the transfer element 2246 and the cleaning element 2242.

[0180] Figures 23A-23B illustrate a 3D printing apparatus or additive manufacturing system according to some embodiments. The 3D printing apparatus 2300 includes a forming platform or build platform 2320 on which multiple cured layers are adhered. A cured layer 2381 formed of material 2391 is directly adhered to the forming platform 2320, a cured layer 2382 formed of material 2392 is directly adhered to the cured layer 2381, and a cured layer 2383 formed of material 2391 is directly adhered to the cured layer 2382. Cured layer 2383 is the most recently cured layer. Figure 23A shows the cured layer 2383 after separation from the release film of the material tank 2312 of the 3D printing apparatus 2300, with liquid material 2398 adhering to it. It is understood that the liquid material 2398 originates from material 2391 in the material tank 2312; that is, the liquid material 2398 and material 2391 are the same material.

[0181] Figure 23A also shows the material tank 2314 of the 3D printing equipment 2300, which contains material 2392. Material 2392 is different from material 2391. For example, material 2391 and material 2392 have different colors, viscosities, and compositions. Objects formed by curing material 2391 and objects formed by curing material 2392 have, for example, different compressive strengths, moduli of elasticity, densities, colors, transparency, and abrasion resistance.

[0182] Figure 23B illustrates the cleaning device of the 3D printing apparatus. The cleaning device 2340 advantageously removes material 2398 adhering to the cured layer 2383. It is understood that after removing material 2398 as much as possible, the forming platform 2320 is allowed to move to align with and immerse in material 2392 in the material tank 2314, which advantageously reduces contamination of material 2392 in the material tank 2314 by material 2398 (or material 2391).

[0183] The cleaning device 2340 in Figure 23B is a positive pressure airflow assembly that applies a positive pressure airflow to the material 2398 adhering to the object to be formed (including the cured layer 2383). Multiple droplets 2399 represent liquid material driven away from the cured layer 2383 by the positive pressure airflow. The multiple droplets 2399 will fall directly into the feed tank 2312.

[0184] On one hand, the cleaning device 2340 shown in Figures 23A-23B removes the material 2398 adhering to the object, thus achieving cleaning. On the other hand, the cleaning device 2340 also forces the removed material 2398 directly back into the hopper 2312, thus achieving material recycling.

[0185] In the embodiments shown in Figures 23A-23B, the molding platform 2320 is aligned with the trough 2312, and the positive pressure airflow provided by the cleaning device 2340 forces the material 2398 separated from the cured layer 2383 directly back into the trough 2312. In other embodiments, a shielding device, such as a protective plate, is provided to prevent the material 2398 separated from the cured layer 2383 from splashing into undesirable areas. Alternatively or additionally, a device, such as a deflector, is provided to guide the splashed material toward the trough 2312.

[0186] In some embodiments, the relative positions of the molding platform 2320, the trough 2312, and the cleaning device 2340 that provides positive pressure airflow are set as needed, as long as the droplets 2399 can return to the trough 2312.

[0187] Figures 24A-24B illustrate a 3D printing apparatus or additive manufacturing system according to some embodiments. The 3D printing apparatus 2400 includes a forming platform or build platform 2420 on which multiple cured layers are adhered. A cured layer 2481 formed from material 2492 is directly adhered to the forming platform 2420, a cured layer 2483 formed from material 2491 is directly adhered to the cured layer 2482, and a cured layer 2484 formed from material 2492 is directly adhered to the cured layer 2481. For example, cured layer 2481 is formed first, then cured layers 2482 and 2483 are formed, and finally cured layer 2484 is formed. Cured layers 2481 and 2482 have the same thickness, and cured layers 2483 and 2484 have the same thickness.

[0188] Figure 24A shows the cured layer 2484 after separation from the release film of the material tank 2414 of the 3D printing equipment 2400. Liquid material 2498 is attached to the cured layer 2483 (formed from material 2491) and the cured layer 2484 (formed from material 2492). It can be understood that the liquid material 2498 comes from material 2492 in the material tank 2414, that is, the liquid material 2498 and material 2492 are the same material.

[0189] Figure 24A also shows the material tank 2414 of the 3D printing equipment 2400, which contains material 2491. Material 2491 is different from material 2492. For example, material 2491 and material 2492 have different colors, viscosities, or compositions. Objects formed by curing material 2491 and objects formed by curing material 2492 may have different compressive strengths, moduli of elasticity, densities, colors, transparency, and abrasion resistance.

[0190] Figure 24B illustrates the cleaning apparatus of the 3D printing equipment. The cleaning apparatus 2440 advantageously removes material 2498 adhering to the cured layers 2483 and 2484. It is understood that after removing material 2498 as much as possible, the forming platform 2420 is allowed to move to align with and immerse in the material 2491 of the material tank 2412, which advantageously reduces contamination of the material 2491 of the material tank 2412 by material 2498 (or material 2492).

[0191] The cleaning device 2440 in Figure 24B is a negative pressure airflow assembly that applies negative pressure airflow to the material 2498 adhering to the object to be formed (including curing layers 2483 and 2484). The material 2498 is drawn in by the cleaning device 2440 and conveyed to the material tank 2414 through the conduit 2442 of the cleaning device 2440. Figure 24B shows droplets or streams of liquid 2499 exiting from the outlet of the conduit 2442, which fall directly into the material tank 2414.

[0192] On one hand, the cleaning device 2440 shown in Figures 24A-24B removes the material 2498 adhering to the object, thus achieving cleaning. On the other hand, the cleaning device 2440 also forces the removed material 2498 directly back into the hopper 2414, thus achieving material recycling.

[0193] In the embodiment shown in Figures 24A-24B, the molding platform 2420 is aligned with the trough 2414, and the negative pressure airflow provided by the cleaning device 2440 forces the material 2498 separated from the cured layers 2483, 2484 directly back into the trough 2414.

[0194] In some embodiments, the relative positions of the molding platform 2420, the trough 2414, and the cleaning device 2440 that provides negative pressure airflow are set as needed, as long as the droplets or flow 2499 can return to the trough 2414. For example, the molding platform 2420 is not aligned with the trough 2414, but the material being drawn up is delivered to the trough 2414 through the conduit 2442 of the cleaning device 2440.

[0195] Figures 25A-25B illustrate 3D printing equipment or additive manufacturing systems according to some embodiments. 3D printing equipment 2500 includes a forming platform or build platform 2520 on which multiple layers that have been cured are adhered.

[0196] Cured layer 2581, formed from material 2591, is directly adhered to molding platform 2520. Cured layer 2582, formed from material 2592, is directly adhered to molding platform 2520. Cured layer 2583, formed from material 2591, is directly adhered to cured layer 2581. Cured layer 2584, formed from material 2592, is directly adhered to cured layer 2582. Cured layer 2585, formed from material 2591, is directly adhered to cured layer 2583. For example, cured layer 2581 is formed first, then cured layers 2582, 2583, and 2584 are formed, and finally cured layer 2585 is formed. Cured layers 2581 and 2582 have different thicknesses, and cured layers 2582, 2583, 2584, and 2585 have the same thickness. For example, the thickness of the cured layer 2581 is 50 μm, and the thickness of the cured layers 2582, 2583, 2584, and 2585 is 100 μm.

[0197] Figure 25A shows the cured layer 2585 after separation from the release film of the material tank 2512 of the 3D printing equipment 2500, with liquid material 2598 adhering to at least the cured layer 2585 (formed from material 2591) and the cured layer 2584 (formed from material 2592). It can be understood that the liquid material 2598 originates from the material 2591 in the material tank 2512, that is, the liquid material 2598 and the material 2591 are the same material.

[0198] Figure 25A also shows the material tank 2514 of the 3D printing equipment 2500, which contains material 2592. Material 2592 is different from material 2591. For example, material 2591 and material 2592 have different colors, viscosities, or compositions. Objects formed by curing material 2591 and objects formed by curing material 2592 may have different compressive strengths, moduli of elasticity, densities, colors, transparency, and abrasion resistance.

[0199] Figure 25B illustrates the cleaning apparatus of a 3D printing device. The cleaning apparatus 2540 advantageously removes material 2598 adhering to the cured layers 2584 and 2585. It is understood that after removing material 2598 as much as possible, the forming platform 2520 is allowed to move to align with and immerse in material 2592 of the feed trough 2514 (omitted in Figure 25B), which advantageously reduces contamination of material 2592 of the feed trough 2514 by material 2598 (or material 2591).

[0200] The cleaning device 2540 in Figure 25B is a scraping assembly. The scraping assembly (e.g., a scraper or brush) is movable relative to the target object to remove material 2598 adhering to the cured layers 2584 and 2585.

[0201] Figures 25C and 25D illustrate the scraping assembly after relative displacement with respect to the cured layer 2585. For example, a drive device (not shown) drives the scraping assembly to translate, thereby scraping material 2598 from the bottom surfaces of the cured layers 2585 and 2584. In other embodiments, a drive device (not shown) drives the molding platform 2520 to translate, thereby scraping material 2598 from the bottom surface of the cured layer 2585 by a stationary or reverse-moving scraping assembly.

[0202] The heights of cured layers 2585 and 2584 are different, so the scraping assembly can optionally move vertically to adjust the spacing between it and the bottom surface of the cured layers. Additionally or alternatively, the scraping assembly is flexible or elastic, so the spacing between the bottom surfaces of the cured layers is acceptable through recoverable contraction or compression.

[0203] Figure 25C shows a scraping assembly removing material 2598 from the bottom surface of cured layer 2585, with the removed material (e.g., in the form of droplets 2599) falling directly into the feed trough 2512. Figure 25D shows a scraping assembly removing material 2598 from the bottom surface of cured layer 2584, with the removed material (e.g., in the form of droplets 2599) falling directly into the feed trough 2512.

[0204] On one hand, the cleaning device 2540 shown in Figures 25A-25B removes the material 2598 adhering to the object, thus achieving cleaning. On the other hand, the cleaning device 2540 also forces the removed material 2598 directly back into the hopper 2512, thus achieving material recycling.

[0205] In some embodiments, the cleaning device or scraping assembly 2540 remains in contact with the outer surface of the object while moving relative to the target object to remove the attached material 2598.

[0206] For example, considering the minor vibrations during the movement of the cleaning device 2540, the cleaning device 2540 includes an inner layer and a resilient outer layer. The resilient outer layer of the cleaning device 2540 contacts the outer surface of the object (e.g., the bottom or side surface of the curing layer 2585). The resilient outer layer helps to prevent damage to the outer surface of the object by the moving cleaning device 2540. Furthermore, the resilient outer layer also helps to eliminate interference problems caused by assembly accuracy and motion accuracy. The term "outer layer" refers to the portion close to the curing layer or the object.

[0207] In some embodiments, the cleaning device or scraping assembly 2540 is always spaced 0.001 mm to 2.000 mm from the outer surface of the object while moving relative to the object to remove the attached material 2598. It is understood that the cleaning device 2540 is only used to remove a portion of the attached material 2598 and guide the removed material 2598 towards a feed trough. For example, the distance between the cleaning device 2540 and the bottom surface of the cured layer 2585 is set to 0.010 mm so that a portion of the attached material 2598 (with a distance greater than 0.010 mm from the bottom surface of the cured layer 2585) is removed. The distance between the cleaning device or scraping assembly 2540 and the outer surface of the object is, for example, 0.001mm to 2.000mm, 0.002mm to 1.000mm, 0.005mm to 0.500mm, 0.010mm to 0.300mm, 0.010mm to 0.200mm, or 0.050mm to 0.100mm.

[0208] Figures 26A-26B illustrate a 3D printing apparatus or additive manufacturing system 2600 according to some embodiments. The 3D printing apparatus 2600 includes a forming platform or build platform 2620 on which multiple cured layers, such as cured layers 2684, 2685 of an object, are adhered.

[0209] Figure 26A shows the cured layer 2685 (the most recently cured layer) after separation from the release film of the material tank 2612 of the 3D printing equipment 2600. Liquid material 2698 is adhered to at least the cured layer 2685 (formed from material 2691) and the cured layer 2684 (formed from a material different from material 2691). It can be understood that the liquid material 2698 originates from material 2691 in the material tank 2612; that is, the liquid material 2698 and material 2691 are the same material.

[0210] Figure 26A shows a cleaning device 2640 that removes material 2698 at least through rotational motion. Figure 26B shows an enlarged view of the cleaning device 2640, with some components of the additive manufacturing system 2600 omitted for illustrative purposes.

[0211] In Figure 26B, material 2698 is attached to cured layers 2685 and 2684, and the cleaning device 2640, which is in contact with material 2698, is rotatable about a predetermined axis. Figure 26B shows the marking point 2645 of the cleaning device 2640, and Figure 26C shows the marking point 2645 of the cleaning device 2640 after rotation. For example, the marking point 2645 in Figure 26B is the position where the cleaning device 2640 contacts the material 2698.

[0212] The predetermined axis of the cleaning device 2640 is perpendicular to the X-axis and Z-axis in Figure 26B. As the cleaning device 2640 rotates, material 2698 attached to the cured layer 2685 is brought to the outer surface of the cleaning device 2640, and material 2697 attached to the cleaning device 2640 is shown in Figure 26C. It can be understood that materials 2691, 2698, and 2697 are the same material.

[0213] As the cleaning device 2640 continues to rotate, the marker point 2645 reaches the lowest point of the cleaning device 2640. At this time, a portion of the material 2697 adhering to the cleaning device 2640 (e.g., droplets or streams 2699) flows into the feed tank 2612, as shown in Figure 26D.

[0214] As the cleaning device 2640 rotates (around a predetermined axis), the material 2690 in contact with the cleaning device 2640 will gradually transfer to the surface of the cleaning device 2640.

[0215] To clean the entire bottom surface of the cured layer 2685, the cleaning device 2640 is capable of moving relative to the cured layer 2685 along the X-axis. Figure 26E shows the cleaning device 2640 translating (while rotating) along the X-axis. The cleaning device 2640 has, for example, rotated at least one revolution, and the circumferential surface of the cleaning device 2640 is distributed with material 2697 of the same or different thicknesses. After leaving the cleaning device 2640, the material 2697 flows or returns to the tank 2612 in the form of droplets or streams 2699.

[0216] Figure 26F shows a transfer element 2646 that translates synchronously with the cleaning device 2640. The transfer element 2646 is capable of contacting the material 2697 attached to the cleaning device 2640. As the cleaning device 2640 rotates, it moves relative to the transfer element 2646 (e.g., the transfer element is fixed by a component not shown). The transfer element 2646 prevents a portion of the material 2697 attached to the cleaning device 2640 from continuing to rotate with the cleaning device 2640, and instead causes it to fall directly into the trough 2612 due to obstruction and gravity.

[0217] In some embodiments, the distance between the transfer element 2646 and the outer surface of the cleaning device 2640 is 0.000 mm to 2.000 mm.

[0218] In some embodiments, the distance between the transfer element 2646 and the outer surface of the cleaning device 2640 is 2.001 mm to 5.000 mm.

[0219] In some embodiments, the transfer element 2646 contacts the outer surface of the cleaning device 2640, and one of the transfer element and the cleaning device 2640 is pressed down by the other by 0.000 mm to 10.000 mm. For example, the cleaning device 2640 has a resilient outer layer, the transfer element 2646 makes line contact or surface contact with the cleaning device 2640, and the contact area of ​​the cleaning device 2640 is recessed by 0.000 mm to 2.000 mm. Alternatively, the transfer element 2646 has a resilient outer layer, the transfer element 2646 makes line contact or surface contact with the cleaning device 2640, and the contact area of ​​the transfer element 2646 is recessed by 0.000 mm to 2.000 mm. Alternatively, both the transfer element 2646 and the cleaning device 2640 have resilient outer layers, the transfer element 2646 makes surface contact with the cleaning device 2640, and the contact areas of the transfer element 2646 and the cleaning device 2640 are respectively recessed by 0.000 mm to 2.000 mm.

[0220] The elastic outer layer material includes at least one of the following: thermoplastic elastomer, silicone, rubber, foam, sponge, polypropylene, and nylon.

[0221] On one hand, the cleaning device 2640 shown in Figures 26A-26F removes the material 2698 adhering to the object, thus achieving cleaning. On the other hand, the cleaning device 2640 also forces the removed material 2698 directly back into the hopper 2612, thus achieving material recycling.

[0222] Figure 27 illustrates a 3D printing apparatus or additive manufacturing system according to some embodiments. The additive manufacturing system 2700 includes a forming platform or build platform on which multiple layers (e.g., cured layers 2783, 2784) are adhered.

[0223] Liquid material 2798 is attached to cured layer 2783 (formed from material 2791) and cured layer 2784 (formed from material 2792). It can be understood that liquid material 2798 comes from material 2792 in material tank 2714, that is, liquid material 2798 and material 2792 are the same material.

[0224] Figure 27 also shows the feed tank 2712 of the additive manufacturing system 2700, in which material 2791 is contained. Material 2791 is different from material 2792. For example, material 2791 and material 2792 have different colors, viscosities, or compositions. Objects formed by curing material 2791 and objects formed by curing material 2792 may have different compressive strengths, moduli of elasticity, densities, colors, transparency, and abrasion resistance.

[0225] Figure 27 illustrates the cleaning device of the 3D printing apparatus. The cleaning device 2744 advantageously removes material 2798 adhering to the cured layers 2783 and 2784. It is understood that after removing material 2798 as much as possible, the forming platform is allowed to move to align with and immerse in material 2791 within the material reservoir 2712, which advantageously reduces contamination of material 2791 in the material reservoir 2712 by material 2798 (or material 2792).

[0226] The cleaning device 2744 in Figure 27 is a negative pressure airflow assembly that applies negative pressure airflow to the material 2798 adhering to the object to be formed (including the cured layers 2783 and 2784). The material 2798 is drawn in by the cleaning device 2744 and transported through the pipe 2748 of the cleaning device 2744 to the recovery container 2754. The recovery container 2754 is used only for recovering material 2792.

[0227] The material trough 2712 is also equipped with a recycling container 2752. The cleaning device 2742 can pick up the material 2711 adhering to the cured layer and transport it to the recycling container 2752 through the pipe 2746. The recycling container 2752 is only used for recycling material 2791.

[0228] Figure 28 illustrates a 3D printing apparatus or additive manufacturing system 2800 according to some embodiments. The additive manufacturing system 2800 includes a forming platform or build platform on which multiple layers (e.g., cured layers 2883, 2884) are adhered.

[0229] Liquid material 2898 is attached to cured layer 2883 (formed of material 2891) and cured layer 2884 (formed of a material different from material 2891). It can be understood that liquid material 2898 comes from material 2891 in material tank 2812, that is, liquid material 2898 and material 2891 are the same material.

[0230] Figure 28 also shows a cleaning device for the additive manufacturing system 2800. The cleaning device 2840 advantageously removes material 2898 adhering to the cured layers 2883 and 2884. In Figure 10, the forming platform is aligned with the recycling container 2850. The cleaning device 2840 is, for example, a scraping assembly. On one hand, the cleaning device 2840 removes material 2898 adhering to the cured layers 2883 and 2884 to achieve cleaning of the cured layers or the object. On the other hand, the material 2898 removed by the cleaning device 2840 enters the recycling container 2850 in the form of, for example, droplets or streams 2899. The recycling container 2850 is used only for recycling material 2891.

[0231] The "material tank" here is, for example, box-shaped, and has a release film that is at least partially transparent. Light projected by the optical unit of the 3D printing equipment or additive manufacturing system can penetrate the release film to solidify the material in the material tank.

[0232] The 3D printing equipment or additive manufacturing system described in this article for manufacturing multi-material objects has at least two feed troughs. For example, two, three, four, five or more feed troughs are provided, each for holding a different material.

[0233] Figure 29 illustrates an auxiliary cleaning device for a 3D printing apparatus. Figure 29 shows material tanks 2912 and 2914, which respectively contain different materials. The forming platform, carrying a cured portion, is aligned with material tank 2912. Then, cleaning device 2940 is used to remove material (from material tank 2912) adhering to the cured portion of the object. As described in other embodiments of this application, cleaning device 2940 allows a portion of the material adhering to the object to be removed and enter material tank 2912. It is understood that cleaning device 2940 may not be able to completely remove all adhering material, or may not be able to completely clean the material adhering to the object.

[0234] The auxiliary cleaning device 2950 shown in Figure 29 can perform a second cleaning of the object. Residual material adheres to the object after cleaning by the cleaning device 2940. For example, by aligning the auxiliary cleaning device 2950 with the forming platform through relative movement, the auxiliary cleaning device 2950 is used to clean the residual material.

[0235] Methods for photopolymer 3D printing using at least two materials are described, for example, in the method disclosed in patent document CN202411553164.7, the entire contents of which are incorporated herein by reference.

[0236] Figures 30A-30D are schematic diagrams of the structure of a 3D printing device in some embodiments of this application. The 3D printing device 3000 includes a frame optical assembly 3010, a support assembly 3020, and a forming platform (not shown in the figures).

[0237] The optical component 3010 defines an optical path (the path that the light emitted by the optical component 3010 travels during propagation), and the optical path has an optical axis 3012 (a geometric straight line corresponding to the "main propagation direction" of the light emitted by the optical component 3010 in space, which can be referred to as the dashed line in Figure 30A).

[0238] The carrier component 3020 is mounted on a frame (not shown in the figure) and is located above the optical component 3010 (or downstream of the light rays projected by the optical component 3010) along the extension direction of the optical axis. The carrier component 3020 has a material tank with its opening facing upwards. The material tank has a release film (the material can be fluorinated ethylene propylene copolymer, silicone, etc.). The substrate included in the carrier component 3020 has a transparent window (the material can be glass, acrylic, etc.). The light emitted from the optical component 3010 passes through the transparent window and the release film and irradiates the material, causing photopolymerization and changing the material from a liquid or paste state to a solid state.

[0239] The forming platform is located above the optical component 3010 along the extension direction of the optical axis (generally vertical, parallel to the Z direction in the figure). The forming platform can move up and down relative to the supporting component 3020, allowing it to move into the material tank.

[0240] When the material tank is located between the molding platform and the optical component 3010, and the material tank is aligned with the optical component 3010 and the molding platform, the light emitted by the optical component 3010 can pass through the material tank and can illuminate the material between the release film and the molding platform, so that the material is cured on the molding platform.

[0241] In this embodiment of the application, the carrier component 3020 includes a substrate 3021 and at least two material trays. The material trays are disposed on the substrate 3021. The substrate 3021 is movable relative to the optical component 3010, such that one of the multiple material trays is located between the molding platform and the optical component 3010 and is aligned with the optical component 3010 and / or the molding platform.

[0242] Figure 30A shows a first material tank 3022, a second material tank 3023, and a third material tank 3024. The first material tank 3022 is used to contain a first material, the second material tank 3023 is used to contain a second material, and the third material tank 3024 is used to contain a third material. The substrate 3021 is moved relative to the optical assembly 3010 to selectively move the first, second, or third material tank directly above or aligned with the optical assembly 3010.

[0243] Different tanks contain materials with different properties (such as different hardness, different transparency, or different color), that is, the first material, the second material, and the third material are different.

[0244] In some embodiments, three troughs are used to hold two materials. For example, the first and second troughs hold the first material, while the third trough holds the second material.

[0245] In some embodiments, at least three troughs are used to hold at least two materials.

[0246] It is understandable that, based on the required material type for the object to be manufactured, the corresponding materials and troughs are provided.

[0247] In some embodiments, by setting at least two material tanks, and the different material tanks contain the same material, that is, the first material, the second material and the third material are the same, during the layer-by-layer curing process, when the material in one of the material tanks is exhausted or about to be exhausted, the 3D printing equipment controls the substrate 3021 to move, so that the other material tanks move directly above the optical component 3010 to achieve continuous printing.

[0248] The 3D printing equipment also includes a drive unit (not shown) mounted on the frame. The drive end of the drive unit is directly or indirectly connected to the substrate 3021 so that the substrate 3021 can move relative to the optical component 3010, and so that a plurality of material slots on the substrate 3021 can move relative to the optical component 3010, so as to selectively move one of the material slots directly above the optical component 3010.

[0249] Please refer to Figures 30A-30D. Optionally, the driving device for the substrate is a linear driving device in which the driving end makes reciprocating linear motion in the first direction (X direction in the figure, and perpendicular to the optical axis), so that the substrate 3021 can be translated relative to the optical component 3010, and multiple feed slots are arranged sequentially in the first direction.

[0250] Referring to Figure 31, alternatively, the driving device for the substrate is a rotating device in which the driving end rotates about an axis extending along a second direction (the Z direction in the figure). The second direction is substantially parallel to the optical axis of the optical component 3010.

[0251] Understandably, the molding platform can move vertically relative to the support component 3020. The 3D printing equipment also includes a drive unit for the molding platform, the drive end of which is connected to the molding platform so that the molding platform can move vertically relative to the support component 3020.

[0252] A drive device for the molding platform moves the molding platform downwards, causing it to enter the first material tank 3022. The distance between the molding platform and the release film in the first material tank is adjusted (the distance between the molding platform and the release film can be designed according to requirements), for example, 5μm to 200μm, or even 20μm, 30μm, or 50μm. An optical component 3010 emits light, exposing a portion of the first material between the molding platform and the release film for a period of time (e.g., 1s-3s). The exposed first material solidifies on the molding platform to form a printed layer with a predetermined pattern cross-section on the molding platform.

[0253] Subsequently, the drive unit for the forming platform moves the forming platform upward, causing the printed layer to separate from the release film. Then, the forming platform moves downward again to adjust the distance between the printed layer and the release film. The optical component 3010 emits light, exposing a portion of the first material between the printed layer and the release film for a period of time (e.g., 1s-3s), and the exposed first material solidifies onto the previously formed printed layer.

[0254] In some scenarios, the forming platform moves upward, causing it and the carried printed layer to detach from the first material tank. The carrier component 3020 moves, causing the second material tank 3023 to align with the optical component 3010. The forming platform moves downward, entering the second material tank 3023, and adjusting the distance between the forming platform and the release film. The optical component 3010 emits light, exposing a portion of the second material between the forming platform and the release film in the second material tank for a period of time (e.g., 1s-3s), and the exposed second material solidifies onto the previously formed printed layer. The forming platform moves upward, causing the release film to peel off the printed layer.

[0255] Referring to Figures 30A-30D, the 3D printing equipment provided in this embodiment further includes a protective device 3030. The protective device 3030 has a first end 3031 and a second end 3032. The first end 3031 is connected to the substrate 3021, and the second end 3032 is connected to the optical component 3010. The protective device 3030 is disposed around the periphery of the optical path. During the relative movement of the substrate 3021 and the optical component 3010, at least a portion of the protective device 3030 is in a relaxed state along its length.

[0256] It is understandable that the connection method between the first end 3031 and the substrate 3021 can be a snap-fit. For example, the substrate 3021 has a slot, and the first end 3031 is placed in the slot and clamped by the locking block of the 3D printing device. Alternatively, adhesives such as glue or tape can be used to fix the first end 3031 to the substrate 3021. Alternatively, fasteners such as rivets or screws can be used to fix the first end 3031 to the substrate 3021.

[0257] Understandably, the connection between the second end 3032 and the optical component 3010 can be a snap-fit ​​connection. For example, the optical component 3010 may have a slot, in which the second end 3032 is positioned and clamped by the locking blocks of the 3D printing device. Alternatively, adhesives such as glue or tape can be used to fix the second end 3032 to the optical component 3010. Or, fasteners such as rivets or screws can be used to fix the second end 3032 to the optical component 3010.

[0258] In some embodiments, the connection between the protective device 3030 and the substrate 3021 or the optical component 3010 is tightly sealed (e.g., using adhesives such as glue or tape). In some embodiments, the sealing of the connection between the protective device 3030 and the substrate 3021 or the optical component 3010 is limited by the mounting gap (e.g., by snap-fit ​​connection).

[0259] Understandably, the protective device 3030 is arranged around the periphery of the optical path, extending continuously along the optical axis and surrounding the optical path 360° to form a ring barrier. The first end 3031 is connected to the substrate 3021, and the second end 3032 is connected to the optical component 3010, so that the substrate 3021, the protective device 3030, and the optical component 3010 enclose a closed space. The light emitted by the optical component 3010 propagates within this closed space. The protective device 3030 can prevent external dust from entering the optical path area, thereby reducing the risk of contamination of the optical component 3010.

[0260] During the relative movement of the substrate 3021 and the optical component 3010, the protective device 3030 has an untensioned redundant part or a retractable part. Therefore, the protective device 3030 allows the enclosed space enclosed by the substrate 3021, the protective device 3030 and the optical component 3010 to change, thereby satisfying the conditions for substrate movement while achieving dust prevention.

[0261] Referring to Figures 30A-30C, the carrier assembly 3020 includes a first material tank 3022, a second material tank 3023, and a third material tank 3024, which are spaced apart in a first direction (the X direction in the figures). The protective device 3030 includes at least a first side portion 3033 and a second side portion 3034, which are spaced apart and opposite to each other in the X direction, and are located on opposite sides of the optical axis. In Figure 30A, the forming platform (not shown) is located directly above the second material tank 3023 and the optical assembly 3010, allowing the optical assembly 3010 to expose the second material in the second material tank 3023. At this time, both the first side portion 3033 and the second side portion 3034 are in a relaxed state. It is understood that the flexible portions of the first side portion 3033 and the second side portion 3034 are untensioned, for example, bent and redundant.

[0262] An exemplary interpretation of the term "redundancy" is as follows: If the spacing between two foundation piles is 1m, and a 1m long elastic rope is installed, the elastic rope is just taut; if a 0.9m long elastic rope is installed, the elastic rope is taut and stretched; if a 1.1m long elastic rope is installed, the elastic rope has a bent or redundant portion.

[0263] During the process of the substrate 3021 moving from the state shown in FIG30A to the state shown in FIG30B, the first side portion 3033 retracts, that is, the first side portion 3033 gradually becomes more relaxed or tends to relax from a relaxed state, the second side portion 3034 gradually stretches or tends to tighten from a relaxed state, and the first material tank 3022 moves to directly above the optical component 3010, so that the optical component 3010 can expose the first material in the first material tank 3022.

[0264] During the movement of substrate 3021 from the state shown in FIG. 30A or FIG. 30B to the state shown in FIG. 30C, the second side portion 3034 retracts, that is, the second side portion 3034 gradually becomes more relaxed or tends to relax from a relaxed state, while the first side portion 3033 gradually extends or tends to tighten from a relaxed state. The third material tank 3024 moves to directly above the optical component 3010, enabling the optical component 3010 to expose the third material in the third material tank 3024. During the movement of substrate 3021, neither the first side portion 3033 nor the second side portion 3034 affects the optical path.

[0265] Referring to Figures 30A-30C, the protective device 3030 has redundant length in the distribution direction of the first end 3031 and the second end 3032, that is, the length of the protective device 3030 is greater than the distance between the first end 3031 and the second end 3032. For example, the protective device 3030 is formed entirely of a flexible material. The flexible material includes at least one of the following: natural rubber, silicone rubber, silicone leather, nylon, polyester film, and rubber.

[0266] In some embodiments, the protective device 3030 includes a rigid portion and a relaxed portion. The rigid portion is the part of the protective device 3030 closer to the substrate, while the relaxed portion is the part of the protective device 3030 farther from the substrate. This is advantageous in limiting the area where deformation occurs during movement to near the optical component 3010, which helps to prevent the deformed portion of the protective device 3030 from affecting or obstructing the optical path, especially at the extreme movement positions of the protective device 3030. The relaxed portion is formed of a flexible material, and the rigid portion includes at least one of the following: metals (e.g., magnesium, aluminum, titanium, and their alloys), and plastics (e.g., polycarbonate, polyphenylene sulfide, etc.).

[0267] Referring to FIG30D, in some embodiments, the 3D printing apparatus further includes a baffle 3040 that is stationary relative to the optical component 3010, the baffle 3040 being connected to the optical component 3010 and located between the protective device 3030 and the optical path.

[0268] In the above embodiment, the baffle 3040 will not move with the substrate 3021, and the baffle 3040 can prevent the deformed part of the protection device 3030 from undesirably moving into the optical path, ensuring that the light propagates smoothly within the protection device 3030.

[0269] The baffle 3040 is a structural component made of rigid materials, such as metal parts, plastic injection molded parts, die casting parts, etc.

[0270] Optionally, the baffle 3040 can be fixed to the optical component 3010 by means of snap-fit, welding, fasteners (such as rivets, screws, etc.).

[0271] In some embodiments, the baffle 3040 is disposed around the periphery of the optical path of the optical component 3010.

[0272] Referring to Figure 31, in some embodiments, the substrate 3121 is rotated about an axis (not shown) extending in the Z direction, such that any one of a plurality of spaced-apart feed slots is aligned with the optical component 3110.

[0273] In some embodiments, the optical component 3110 essentially only allows light to be projected onto a single feed tray 3122, 3123, 3124. Since the optical component 3110 is stationary, the axis of rotation of the substrate 3121 is spaced apart from the optical axis (shown as a dashed line) of the optical component 3110. Through the eccentric rotation of the substrate 3121 relative to the optical component 3010, multiple feed trays 3122, 3123, 3124 can alternately enter the exposure area of ​​the optical path, while at least a portion of the protective device 3030 is in a relaxed state and always surrounds the optical path of the optical component 3010.

[0274] In some embodiments, the optical component 3110 can rotate about an optical axis, and the rotation direction of the optical component 3110 is consistent with the rotation direction of the substrate 3121. For example, when the substrate 3121 rotates clockwise, the optical component 3110 also rotates clockwise; when the substrate 3121 rotates counterclockwise, the optical component 3110 also rotates counterclockwise.

[0275] In the above embodiment, since the rotation direction of the optical component 3110 is the same as the rotation direction of the substrate 3121, the optical component 3110 and the substrate 3121 can rotate in the same direction but asynchronously. The displacements of the first end 3131 and the second end 332 of the flexible protective device 3130 are different, but the flexible protective device 3130 maintains dust protection for the optical component 3110; for example, at least a portion of the protective device 3130 is in a relaxed state.

[0276] It is understood that the 3D printing equipment of this application has at least two material troughs. For example, two, three, four or more. Each material trough can hold the same or different materials.

[0277] This application provides a 3D printing apparatus for manufacturing a target object, comprising: a first material tank configured to contain a first material; a second material tank configured to contain a second material different from the first material; a forming platform capable of moving along a first direction toward or away from the first material tank or the second material tank; and a cleaning device configured to: drive the first material attached to the target object to move to the first material tank; or drive the second material attached to the target object to move to the second material tank.

[0278] In some embodiments, the cleaning device is configured to: drive a first material attached to a target object to move to the first material tank when the molding platform is aligned with the first material tank; or drive a second material attached to a target object to move to the second material tank when the molding platform is aligned with the second material tank.

[0279] In some embodiments, the cleaning device includes at least one of the following: a scraping assembly configured to move relative to a first material or a second material attached to a target object to separate the attached first material or the second material from the target object; a positive pressure airflow assembly configured to apply a positive pressure airflow to the first material or the second material attached to the target object; or a negative pressure airflow assembly configured to apply a negative pressure airflow to the first material or the second material attached to the target object to allow the first material or the second material to flow through a conduit of the negative pressure airflow assembly to a first trough or a second trough.

[0280] In some embodiments, the scraping component is configured to: maintain contact with the outer surface of the target object while moving relative to the target object; or maintain a distance of 0.001 mm to 2.000 mm from the outer surface of the target object while moving relative to the target object.

[0281] In some embodiments, the scraping assembly includes a cleaning element capable of rotating about a predetermined axis perpendicular to a first direction.

[0282] In some embodiments, the cleaning element of the scraping assembly is movable along a second direction, which is perpendicular to the first direction and the predetermined axis.

[0283] In some embodiments, the scraping assembly further includes a transfer element configured to move relative to the cleaning element to remove a first or second material adhering to the cleaning element.

[0284] In some embodiments, the transfer element is configured such that it is spaced from the outer surface of the cleaning element by 0.000 mm to 2.000 mm; spaced from the outer surface of the cleaning element by 2.001 mm to 5.000 mm; or in contact with the outer surface of the cleaning element, and one of the transfer element and the cleaning element is pressed down by the other by 0.000 mm to 10.000 mm.

[0285] In some embodiments, the scraping assembly includes a cleaning element capable of moving in a second direction perpendicular to the first direction, the cleaning element including at least one of a scraper or a brush.

[0286] In some embodiments, the scraping assembly includes an inner layer and a resilient outer layer.

[0287] In some embodiments, the material of the elastic outer layer includes at least one of the following: thermoplastic elastomer, silicone, rubber, foam, sponge, polypropylene, and nylon.

[0288] In some embodiments, the 3D printing apparatus further includes a drive mechanism configured to move at least one of the following: a first material trough, a second material trough, a forming platform, and a cleaning device.

[0289] In some embodiments, the 3D printing apparatus further includes a level maintaining device for defining the level of a first material in a first tank, a cleaning device being mounted to the level maintaining device, and the level maintaining device being movable in a second direction perpendicular to the first direction.

[0290] In some embodiments, the cleaning device of the 3D printing apparatus includes a first cleaning element and a second cleaning element, wherein the first cleaning element is configured to move a first material attached to a target object to a first feed trough, and the second cleaning element is configured to move a second material attached to the target object to a second feed trough.

[0291] In some embodiments, in the 3D printing apparatus, the first cleaning element and the second cleaning element are driven independently or together.

[0292] In some embodiments, the 3D printing apparatus further includes an auxiliary cleaning device configured to continue cleaning the first or second material of the target object after the cleaning device removes the first or second material attached to the target object.

[0293] This application also provides a 3D printing apparatus for manufacturing a target object, comprising: a first material tank configured to contain a first material; a second material tank configured to contain a second material different from the first material; a forming platform capable of moving along a first direction toward or away from the first material tank or the second material tank; and a cleaning device configured to: drive the first material attached to the target object to move to a first recycling container; and / or drive the second material attached to the target object to move to a second recycling container.

[0294] In some embodiments, the first recycling container is a first trough, and the second recycling container is a second trough.

[0295] In some embodiments, the first recycling container is spaced apart from the first trough, and the second recycling container is spaced apart from the second trough.

[0296] This application also provides a method for forming a target object by additive manufacturing, comprising: projecting light through an optical unit to form a first cured layer of the target object from a first material in a first material tank; moving the first cured layer away from the first material tank through a driving device; driving the first material attached to the target object to move to a first recycling container through a cleaning device; and projecting light through an optical unit to form a second cured layer of the target object from a second material in a second material tank.

[0297] In some embodiments, the first recycling container is a first trough; or the first recycling container is spaced apart from the first trough.

[0298] In some embodiments, the aforementioned method further includes: after driving the first material attached to the target object to move to the first recycling container, cleaning the remaining first material attached to the target object by an auxiliary cleaning device.

[0299] 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.

[0300] In some embodiments, the first support device is formed as a plate-shaped element or a box-shaped element.

[0301] 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.

[0302] In some embodiments, the first carrier includes at least one collection container configured to collect the first material propelled by the first actuator.

[0303] 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.

[0304] 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.

[0305] In some embodiments, the first actuator includes a lower portion configured to prevent the flow of first material through the lower portion.

[0306] In some embodiments, the additive manufacturing system further includes a first feeding mechanism configured to supply a first material to a first support device.

[0307] In some embodiments, the first feeding mechanism is configured to be stationary or movable relative to the first carrying device.

[0308] 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.

[0309] 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.

[0310] 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.

[0311] 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.

[0312] 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.

[0313] 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.

[0314] 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.

[0315] 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.

[0316] 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.

[0317] 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.

[0318] 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.

[0319] 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.

[0320] 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.

[0321] 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.

[0322] In some embodiments, the airflow assembly is configured to apply a positive or negative pressure airflow to the solidified object.

[0323] In some embodiments, the adsorption component includes a sponge or a fabric.

[0324] In some embodiments, the cleaning container is configured to contain cleaning agent.

[0325] In some embodiments, the absorbent layer is made of a soft, porous material.

[0326] 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.

[0327] 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, polyether, polyvinyl alcohol, and polyurethane.

[0328] In some embodiments, the additive manufacturing system further includes a heating element configured to raise the temperature of at least one absorption layer.

[0329] 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.

[0330] 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.

[0331] 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.

[0332] In some embodiments, the positive pressure component or the negative pressure component is directly connected to the collection container (or is integrally formed).

[0333] In some embodiments, the absorbent layer is removable or replaceable.

[0334] In some embodiments, the additive manufacturing system further includes a conveying mechanism for conveying the absorbent layer.

[0335] 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.

[0336] 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.

[0337] US20170182708A1 discloses a scheme with multiple movable printheads and a fixed optical engine. Dust protection for the optical engine only requires a fixed dust cover, such as metal or plastic. EP2699406B1 discloses a scheme with multiple movable printheads and a movable optical unit. Since the optical unit needs to be constantly moving, dust protection for the optical unit cannot be achieved. Even if a dustproof glass is placed in the optical path of the optical unit, dust can remain and accumulate on the dustproof glass, thus failing to prevent dust from obstructing the optical path. Document CN115243865A discloses a scheme with multiple movable trays and a fixed optical unit. The light projected by the optical unit passes through the glass on the substrate and the transparent film of the tray. In this optical path, there is a gap between the glass on the substrate and the transparent film of the tray because the tray moves relative to the glass on the substrate to switch to different trays. Due to the existence of this gap, dust can easily enter the gap and accumulate on the glass on the substrate, thus causing dust accumulation.

[0338] This application provides a 3D printing apparatus, comprising: a substrate capable of moving along a predetermined direction; a first tray mounted on the substrate; a second tray mounted on the substrate and spaced apart from the first tray; an optical component configured to project light onto the first tray or the second tray; and a protective device connected to the substrate and the optical component, and including an adjustment portion formed of a flexible material.

[0339] In some embodiments, the 3D printing apparatus has: a first state in which a first tray is aligned with an optical component; and a second state in which a second tray is aligned with an optical component.

[0340] In some embodiments, the adjustment portion of the protective device includes a first side and an opposing second side, wherein during the transition of the 3D printing device from a first state to a second state, the first side of the adjustment portion tends to tighten, while the second side of the adjustment portion tends to loosen.

[0341] In some embodiments, the protective device has a first end for connecting a substrate and a second end for connecting an optical component, the first end being sealed to a stationary optical component and the second end being sealed to a movable substrate.

[0342] In some embodiments, the protective device includes a first portion close to the substrate and a second portion away from the substrate, the second portion including an adjustment portion, wherein the first portion includes: a rigid portion formed of a rigid material; or a flexible portion formed of a flexible material.

[0343] In some embodiments, the flexible material includes at least one of the following: natural rubber, silicone rubber, silicone leather, nylon, polyester film, and rubber.

[0344] In some embodiments, the 3D printing apparatus further includes a baffle connected to the optical components, the baffle being surrounded by the protective device.

[0345] In some embodiments, the predetermined direction includes: a linear direction, wherein the first tray and the second tray are spaced apart along the linear direction; or a rotational direction, wherein the first tray and the second tray are spaced apart along the rotational direction.

[0346] In some embodiments, the optical component includes a DLP optical engine; or the optical component includes a light source, and a first tray is equipped with a first LCD projection module aligned with the first tray, and a second tray is equipped with an LCD projection module aligned with the second tray; or the optical component includes a light source, and a first tray is equipped with a first LCOS projection module aligned with the first tray, and a second tray is equipped with an LCOS projection module aligned with the second tray.

[0347] This application also provides a 3D printing method, which includes: aligning a first tray and an optical component, including: moving a substrate to align the first tray mounted on the substrate with the optical component; projecting light onto the first tray through the optical component; and aligning a second tray and an optical component, including: moving the substrate to align the second tray mounted on the substrate with the optical component, wherein during the alignment of the second tray and the optical component, the relaxation state of an adjustment portion formed of a flexible material of a protective device changes, wherein the protective device is connected to the substrate and the optical component.

[0348] 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.

[0349] 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. A 3D printing device for manufacturing target objects, characterized in that, include: The first material tank is configured to hold the first material; The second material tank is configured to hold a second material that is different from the first material; The forming platform is capable of moving along a first direction to approach or move away from the first or second material trough; and The cleaning device is configured as follows: - Drives the first material attached to the target object to move to the first feed trough; or - Drives the second material attached to the target object to move to the second feed tank.

2. The 3D printing equipment according to claim 1, wherein the cleaning device is configured as follows: - When the molding platform is aligned with the first material trough, it drives the first material attached to the target object to move into the first material trough; or - When the molding platform is aligned with the second material trough, it drives the second material attached to the target object to move to the second material trough.

3. The 3D printing apparatus according to any one of the preceding claims, wherein the cleaning device comprises at least one of the following: A scraping assembly configured to move relative to a first or second material attached to a target object, so as to separate the attached first or second material from the target object; A positive pressure airflow assembly is configured to apply a positive pressure airflow to a first or second material attached to a target object; or A negative pressure airflow assembly is configured to apply negative pressure airflow to a first material or a second material attached to a target object, so that the first material or the second material flows through the pipes of the negative pressure airflow assembly to a first trough or a second trough.

4. The 3D printing apparatus according to any one of the preceding claims, wherein the scraping assembly is configured as any one of the following: - Maintain contact with the outer surface of the target object while moving relative to the target object; or - The distance between the object and the outer surface of the target object is 0.001mm to 2.000mm, while the object moves relative to the target object.

5. The 3D printing apparatus according to any one of the preceding claims, wherein the scraping assembly includes a cleaning element rotatable about a predetermined axis perpendicular to the first direction.

6. The 3D printing apparatus according to any one of the preceding claims, wherein the cleaning element of the scraping assembly is movable along a second direction, the second direction being perpendicular to the first direction and the predetermined axis.

7. The 3D printing apparatus according to any one of the preceding claims, wherein the scraping assembly further comprises a transfer element configured to move relative to the cleaning element to remove a first material or a second material adhering to the cleaning element.

8. The 3D printing apparatus according to any one of the preceding claims, wherein the transfer element is configured as any one of the following: - The distance between the cleaning element and the outer surface of the cleaning element is 0.000mm to 2.000mm; - The distance between the cleaning element and the outer surface is 2.001mm to 5.000mm; or - It contacts the outer surface of the cleaning element, and one of the transfer element and the cleaning element is pressed down by the other by 0.000mm to 10.000mm.

9. The 3D printing apparatus according to any one of the preceding claims, wherein the scraping assembly includes a cleaning element movable in a second direction perpendicular to the first direction, the cleaning element including at least one of a scraper or a brush.

10. The 3D printing apparatus according to any one of the preceding claims, wherein the scraping assembly comprises an inner layer and an elastic outer layer.

11. The 3D printing apparatus according to any one of the preceding claims, wherein the material of the elastic outer layer comprises at least one of the following: thermoplastic elastic material, silicone, rubber, foam, sponge, polypropylene, nylon.

12. The 3D printing apparatus according to any one of the preceding claims further includes a drive mechanism configured to move at least one of the following: a first material tank, a second material tank, a forming platform, and a cleaning device.

13. The 3D printing apparatus according to any one of the preceding claims further includes a level maintaining device for defining a level of a first material in a first tank, the cleaning device being mounted to the level maintaining device, and the level maintaining device being movable in a second direction perpendicular to the first direction.

14. The 3D printing apparatus according to any one of the preceding claims, wherein the cleaning device includes a first cleaning element and a second cleaning element, wherein the first cleaning element is configured to move a first material attached to a target object to a first feed trough, and the second cleaning element is configured to move a second material attached to the target object to a second feed trough.

15. The 3D printing apparatus according to any one of the preceding claims, wherein the first cleaning element and the second cleaning element are driven independently or synchronously.

16. The 3D printing apparatus according to any one of the preceding claims further includes an auxiliary cleaning device, the auxiliary cleaning device being configured to continue cleaning the first or second material of the target object after the cleaning device removes the first or second material attached to the target object.

17. The 3D printing apparatus according to any one of the preceding claims, wherein the auxiliary cleaning device is configured to separate uncured material adhering to a target object from the target object, wherein the cleaning unit includes at least one absorbent layer configured to allow the uncured material to flow into the pores or pores of the absorbent layer.

18. The 3D printing apparatus according to any one of the preceding claims, wherein, The absorption layer includes a first absorption layer and a second absorption layer, which are composed of different porous materials.

19. The 3D printing apparatus according to any one of the preceding claims further includes a heating element configured to raise the temperature of at least one absorption layer.

20. The 3D printing apparatus according to any one of the preceding claims further includes a positive pressure component configured to apply an airflow to blow uncured material off a target object and configured to facilitate the flow of the uncured material in the pores of the absorbent layer.

21. The 3D printing apparatus according to any one of the preceding claims further includes a negative pressure assembly configured to force airflow and the uncured material to flow through the at least one absorbent layer.

22. The 3D printing apparatus according to any one of the preceding claims, wherein the positive pressure component or the negative pressure component is equipped with a collection container configured to collect material flowing through the at least one absorbent layer.

23. The 3D printing apparatus according to any one of the preceding claims, wherein the auxiliary cleaning device further comprises a cleaning container configured to contain a cleaning agent.

24. The 3D printing apparatus according to any one of the preceding claims further includes a conveying mechanism for conveying the absorbent layer.

25. The 3D printing apparatus according to any one of the preceding claims, further comprising: The substrate is configured to support the first and second material tanks and is movable to change the positions of the first and second material tanks. An optical component configured to project light into a first or second trough; and The protective device is connected to the substrate and optical components, and includes an adjustment section formed of flexible material.

26. The 3D printing apparatus according to any one of the preceding claims, wherein the 3D printing apparatus comprises: In the first state, the first feed trough is aligned with the optical component; and In the second state, the second feed trough is aligned with the optical component.

27. The three-dimensional printing apparatus according to any one of the preceding claims, wherein the adjusting portion of the protective device includes a first side and an opposing second side, wherein during the switching of the three-dimensional printing apparatus from a first state to a second state, the first side of the adjusting portion tends to be tensioned while the second side of the adjusting portion tends to be relaxed.

28. The three-dimensional printing apparatus according to any one of the preceding claims, wherein the protective device has a first end for connecting a substrate and a second end for connecting an optical component, the first end being sealed to a stationary optical component and the second end being sealed to a movable substrate.

29. The three-dimensional printing apparatus according to any one of the preceding claims, wherein the protective device comprises a first portion close to the substrate and a second portion distant from the substrate, the second portion comprising an adjustment portion, wherein the first portion comprises: Rigid parts formed by rigid materials; Or a flexible part formed by flexible materials.

30. The three-dimensional printing apparatus according to any one of the preceding claims, wherein the flexible material comprises at least one of the following: natural rubber, silicone rubber, silicone leather, nylon, polyester film, and rubber.

31. The three-dimensional printing apparatus according to any one of the preceding claims further includes a baffle connected to the optical components, the baffle being surrounded by the protective device.

32. The three-dimensional printing apparatus according to any one of the preceding claims, wherein the predetermined orientation includes: - Straight direction, wherein the first trough and the second trough are spaced apart in a straight direction; or - Rotation direction, wherein the first trough and the second trough are spaced apart along the rotation direction.

33. The three-dimensional printing apparatus according to any one of the preceding claims, wherein, The optical components include a DLP optical engine; or The optical components include a light source, and the first feed tank is equipped with a first LCD projection module aligned with the first feed tank, and the second feed tank is equipped with an LCD projection module aligned with the second feed tank. or The optical components include a light source, and the first feed tank is equipped with a first LCOS projection module aligned with the first feed tank, and the second feed tank is equipped with an LCOS projection module aligned with the second feed tank.

34. A 3D printing device for manufacturing a target object, characterized in that, include: The first material tank is configured to hold the first material; The second material tank is configured to hold a second material that is different from the first material; The forming platform is capable of moving along a first direction to approach or move away from the first or second material trough; and The cleaning device is configured as follows: - Drive the first material attached to the target object to move to the first recycling container; and / or - Drives the second material attached to the target object to move to the second recycling container.

35. The 3D printing apparatus of claim 34, wherein the first recycling container is a first material trough, and the second recycling container is a second material trough.

36. The 3D printing apparatus of claim 34 or 35, wherein the first recycling container is spaced apart from the first hopper, and the second recycling container is spaced apart from the second hopper.

37. A method for forming a target object by additive manufacturing, characterized in that, include: Light is projected through an optical unit to cause the first material in the first tank to form a first solidified layer of the target object; The first cured layer is moved away from the first material tank by a driving device; The cleaning device drives the first material adhering to the target object to move to the first recycling container. and The optical unit projects light to cause the second material in the second tank to form a second cured layer of the target object.

38. The method of claim 37, wherein -The first recycling container is the first hopper; or - The first recycling container is separated from the first material tank.

39. The method according to claim 37 or 38, further comprising: After the first material adhering to the target object is moved to the first recycling container, the remaining first material adhering to the target object is cleaned by an auxiliary cleaning device.

40. An additive manufacturing method, comprising: Projecting light causes the first material carried by the first support device to solidify and adhere to the molding platform; Using a cleaning unit, uncured material adhering to a cured object on the molding platform is separated from the cured object. and Projecting light causes the second material carried by the second support device to solidify and adhere to the molding platform.

41. A three-dimensional printing method, characterized in that, include: Aligning the first feed tank and the optical component includes: moving the substrate to align the first feed tank mounted on the substrate with the optical component; Light is projected onto the first feed tank through optical components; and Aligning the second feeder and the optical component includes: moving the substrate to align the second feeder mounted on the substrate with the optical component, wherein during the alignment of the second feeder and the optical component, the relaxation state of an adjustment portion formed of a flexible material of a protective device changes, wherein the protective device is connected to the substrate and the optical component.

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