3D Printing Device and Its Powder Spreading System

Abstract

The present application discloses a 3D printing device and its powder spreading system. The 3D printing device includes a forming platform and a forming chamber located on the forming platform. The forming platform has a forming area and a first area and a second area located on opposite sides of the forming area. The powder spreading system includes: a first material receiving component disposed in the forming chamber and suspended in the first area, and a powder spreading device disposed under the first material receiving component for performing powder spreading operations. The powder spreading device includes a powder spreading roller for laying powder on the forming area and a second material receiving component for low-position powder dropping. The second material receiving component is used to dock with the first material receiving component to receive powder and cache it when following the powder spreading roller and moving towards the first area, and to release the powder at a low position by the powder spreading roller when following the powder spreading roller and moving towards the second area. Through the docking and separation of the first material receiving component and the second material receiving component at specific positions, the low-position release of powder is achieved, thereby avoiding dust generation and ensuring the forming environment in the forming chamber.

Description

Technical Field

[0001] This application relates to the technical field of 3D printing, and particularly to a 3D printing device and its powder spreading system. Background Art

[0002] 3D printing technology is a kind of rapid prototyping technology. It is a technology that constructs objects by layer-by-layer printing based on digital model files, using bondable materials such as powdered metals, plastics, and resins. Under the trend of the rapid development of industrial technologies, various 3D printing technologies using powder materials as raw materials have emerged continuously. For example, Selective Laser Melting (SLM), Selective Laser Sintering (SLS), Direct Laser Metal Deposition (DLMD), Electron Beam Melting (EBM), Selective Heat Sintering (SHS), etc. In various 3D printing devices using powder materials as raw materials, 3D components are formed in their forming areas.

[0003] Taking an SLS-type 3D printing device as an example, during printing, a powder spreading system is required to lay powders layer by layer in the forming area. During the powder spreading process, when powder is fed, the height at which the powder falls will affect the forming quality. For example, in related technologies, the powder is directly dropped from the powder supply mechanism to the forming platform, which will form dust, thus affecting the forming environment. Therefore, how to achieve low-position powder dropping during the powder spreading operation is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the related technologies, the purpose of this application is to provide a 3D printing device and its powder spreading system, which are used to solve the technical problem that the dust formed by high-position powder dropping will affect the forming quality.

[0005] To achieve the above and other related objectives, a powder spreading system for a 3D printing device is provided in the first aspect of the present application. The 3D printing device includes a forming platform and a forming chamber located on the forming platform. The forming platform has a forming area and a first area and a second area located on opposite sides of the forming area. The powder spreading system includes: a first material receiving component, which is arranged in the forming chamber and suspended in the first area; a powder spreading device, which is arranged under the first material receiving component and is used to be driven to move back and forth between the first area and the second area to perform powder spreading operations on the forming platform. The powder spreading device includes a powder spreading roller for spreading powder on the forming area and a second material receiving component for low-position powder dropping. Among them, the second material receiving component is used to dock with the first material receiving component to receive powder from the first material receiving component and cache it when following the powder spreading roller to move towards the first area, and to release the cached powder at a low position by the powder spreading roller when following the powder spreading roller to move towards the second area.

[0006] In the second aspect of the present application, a 3D printing device is provided, including: a forming platform, which has a forming area and a first area and a second area located on opposite sides of the forming area. A component mechanism is arranged corresponding to the forming area. The component mechanism is used to move layer by layer in the vertical direction to attach 3D components that are formed layer by layer by irradiating the forming area with an optical system; the powder spreading system as described in any embodiment of the first aspect of the present application, which is used to spread powder in the forming area; an optical system, which is used to emit a light beam to irradiate the powder in the forming area; a control device, which is connected to the optical system, the component mechanism, and the powder spreading system, and is used to control the powder spreading system to spread powder into the forming area during a printing operation, control the optical system to irradiate the powder in the forming area, and control the component mechanism to move vertically during a printing operation to attach the layer-by-layer formed 3D components on the component mechanism.

[0007] In summary, for the 3D printing device and its powder spreading system provided in the present application, the powder spreading operation is realized by a powder spreading device that can move back and forth between the first area and the second area of the forming platform. By arranging a first material receiving component suspended in the first area in the forming chamber and a second material receiving component that can move with the powder spreading roller, the first material receiving component and the second material receiving component can be docked when the powder spreading roller moves towards the first area, so that the powder is cached in the second material receiving component. In addition, when the powder spreading roller moves towards the second area, the first material receiving component and the second material receiving component can be separated from each other, so that the second material receiving component releases the powder at a low position, thereby avoiding dust flying and ensuring the forming environment in the forming chamber. Description of the Drawings

[0008] The specific features involved in this application are shown in the appended claims. The characteristics and advantages of the invention involved in this application can be better understood by referring to the exemplary embodiments and the accompanying drawings described in detail below. A brief description of the drawings is as follows:

[0009] Figure 1 It shows a schematic structural diagram of a 3D printing device in an embodiment of this application.

[0010] Figure 2 It shows a schematic structural diagram of a forming platform in an embodiment of this application.

[0011] Figure 3 It shows a schematic structural diagram of a powder spreading system in an embodiment of this application.

[0012] Figure 4 and Figure 5 respectively show a schematic diagram of a first powder return tank in an embodiment of this application.

[0013] Figure 6 It shows a schematic diagram of a powder return detection mechanism detecting the powder surface distance in an embodiment of this application.

[0014] Figure 7 It shows a schematic diagram of the forming area before the paving stage in an embodiment of this application.

[0015] Figure 8 It shows a schematic diagram of the powder spreading operation in the paving stage in an embodiment of this application.

[0016] Figure 9 It shows a schematic diagram of a powder return detection mechanism detecting the lower limit distance of the tank in an embodiment of this application.

[0017] Figure 10 It shows a schematic diagram of the forming area after the paving is completed in an embodiment of this application.

[0018] Figure 11 It shows a schematic diagram of the powder spreading operation in the printing stage in an embodiment of this application.

[0019] Figure 12 and Figure 13 respectively show a schematic structural diagram of a powder return detection mechanism from different perspectives in an embodiment of this application.

[0020] Figure 14 It shows a cross-sectional schematic diagram of a powder return detection mechanism in an embodiment of this application.

[0021] Figure 15 It shows a split structural schematic diagram of a second base in an embodiment of this application.

[0022] Figure 16It shows a cross-sectional schematic diagram of the cooling mechanism in an embodiment of the present application.

[0023] Figure 17 It shows a schematic diagram of the cooling bodies connected in series with each other in an embodiment of the present application.

[0024] Figure 18 It shows a schematic diagram of the cooling bodies connected in parallel with each other in an embodiment of the present application.

[0025] Figure 19 It shows a schematic diagram of the gas guiding structure in an embodiment of the present application.

[0026] Figure 20 Shown as Figure 19 A cross-sectional schematic diagram of the gas guiding structure in the shown embodiment.

[0027] Figure 21 Shown as Figure 19 A partially enlarged schematic diagram of the gas guiding structure in the shown embodiment.

[0028] Figure 22 It shows a schematic diagram of the gas guiding structure in another embodiment of the present application.

[0029] Figure 23 It shows a schematic diagram of the structure of the second material receiving component in an embodiment of the present application.

[0030] Figure 24 And Figure 25 Respectively show schematic diagrams of the structure of the second material receiving hopper in different embodiments of the present application.

[0031] Figure 26 It shows a schematic diagram of the state of the second material receiving hopper during the reverse powder spreading operation in an embodiment of the present application.

[0032] Figure 27 It shows a schematic diagram of the structure of the door component in an embodiment of the present application.

[0033] Figures 28 to 30 Respectively show schematic diagrams of the process of the second material receiving hopper passing through the first material receiving component and docking with the first material receiving component in an embodiment of the present application.

[0034] Figure 31 It shows a schematic diagram of the connecting piece in an embodiment of the present application.

[0035] Figure 32 It shows a schematic diagram of the first material receiving component in an embodiment of the present application.

[0036] Figure 33 It shows a cross-sectional schematic diagram when the second material receiving hopper docks with the first material receiving component in an embodiment of the present application.

[0037] Figure 34 Shown as this application Figure 33 The partial enlarged schematic diagram at position A in the embodiment shown.

[0038] Figure 35 and Figure 36 Respectively shown as the cross-sectional schematic diagrams of the powder spreading device in different perspectives in an embodiment of this application.

[0039] Figure 37 and Figure 38 Respectively shown as the cross-sectional schematic diagrams of the powder spreading device in different perspectives in another embodiment of this application.

[0040] Figure 39 Shown as the structural schematic diagram of the first scraper in an embodiment of this application.

[0041] Figure 40 Shown as the disassembled structural schematic diagram of the first scraper relative to the second base in an embodiment of this application.

[0042] Figure 41 Shown as the schematic diagram of the first scraper disposed in the installation space in an embodiment of this application.

[0043] Figure 42 Shown as the schematic diagram of the contact between the first blade part and the powder spreading roller in an embodiment of this application.

[0044] Figure 43 Shown as the structural schematic diagram of the third scraper in an embodiment of this application.

[0045] Figure 44 Shown as the schematic diagram of the second scraper and the third scraper disposed on the second base in an embodiment of this application.

[0046] Figure 45 Shown as the schematic diagram of the line contact between the third blade part and the powder spreading roller in an embodiment of this application.

[0047] Figure 46 Shown as the disassembled structural schematic diagram of the third scraper and the side support plate in an embodiment of this application. Detailed implementation manners

[0048] The following specific embodiments illustrate the implementation manners of the present application. Those skilled in the art can easily understand the advantages of the present application and the technical effects that can be achieved from the content disclosed in this specification. In the following description, some embodiments may refer to the accompanying drawings. It should be understood that other embodiments without the drawn drawings may also be used, and specific structural, component or mechanism, assembly, and operational changes may be made without departing from the spirit and scope of the present application. The following detailed description should not be considered restrictive, and the scope of the embodiments of the present application is only defined by the claims disclosed in the present application. The terms used herein are only for describing specific embodiments and are not intended to limit the present application.

[0049] It should be understood that although the terms first, second, or third, etc. may be used herein to describe various elements or parameters in some embodiments, these elements or parameters should not be limited by these terms. These terms are only used to distinguish one element or parameter from another, rather than to define the order, priority, or importance of multiple elements. For example, the first material receiving component may be referred to as the second material receiving component, and similarly, the second material receiving component may be referred to as the first material receiving component, without departing from the scope of the various described embodiments.

[0050] Furthermore, as used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. It should be further understood that the terms "comprising", "including" indicate the presence of the described features, steps, operations, elements, components, items, types, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, types, and / or groups. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or devices. Additionally, the term "and / or" that may be used hereinafter describes the association relationship of associated objects and indicates that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the character " / ", unless otherwise specified, generally represents an "and / or" relationship between the associated objects before and after. Additionally, in the description of the embodiments of the present application, "a plurality of" means two or more. Furthermore, the terms "or" and "and / or" used herein are interpreted as inclusive, or meaning any one or any combination. An exception to this definition only occurs when the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0051] It should also be understood that when an element such as a layer, region, or substrate is referred to as being "on" another element or extending "onto" another element, the element can be directly on the other element or directly extend onto the other element, or there can also be intervening elements. Conversely, when an element is referred to as being "directly on" another element or "directly extending onto" another element, there are no intervening elements. It will also be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there can be intervening elements. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements. Additionally, the term "coupled" generally means physically, mechanically, magnetically, and / or electrically coupled or connected, and in the absence of specific contrary language, does not exclude the presence of intervening elements between the items being coupled or associated.

[0052] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe the relationship of one element, layer, or region to another element, layer, or region as illustrated in the figures. It will be understood that these terms are intended to encompass different device orientations other than the orientation depicted in the figures. In the present application, the "vertical", "horizontal", "parallel" are defined as: including the cases within ±10% based on the standard definitions. For example, vertical generally refers to an angle of 90° relative to a reference line, but in the present application, vertical refers to the cases within 80° to 100°. Unless otherwise explicitly stated, comparative quantity terms (such as "above" and "below") are intended to encompass the concept of equality. As an example, "above" can not only mean "greater than" in the mathematical sense, but also can mean "equal to".

[0053] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the present application. When used herein, unless the context clearly dictates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms as well. It will also be understood that when used herein, the terms "comprises", "comprising", "includes", and / or "including" specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0054] In view of the technical problems mentioned in the background art, the present application discloses a 3D printing device and its powder spreading system, and the powder spreading operation is realized by a powder spreading device that can move back and forth between a first area and a second area of the forming platform. By arranging a first material receiving component suspended in the first area and a second material receiving component that can move with the powder spreading roller in the forming chamber, when the powder spreading roller moves towards the first area, the docking of the first material receiving component and the second material receiving component can be realized, so that the powder is cached in the second material receiving component. In addition, when the powder spreading roller moves towards the second area, the first material receiving component and the second material receiving component can be separated from each other, so that the second material receiving component releases the powder at a low position, thereby avoiding dust flying and ensuring the forming environment in the forming chamber.

[0055] In the present application, the 3D printing device is a device that uses powder as a raw material and forms the powder layer by layer to construct a 3D component. The powder is a powdery material, and the powder includes nylon powder, metal powder, plastic powder, ceramic powder, mixed powder, etc. The powder is, for example, thermoplastic rubber (TPR), thermoplastic elastomer; wherein, the thermoplastic elastomer includes any one of polyurethane elastomer (TPU), nylon elastomer (TPAE), polyester elastomer (TPEE), EVA elastomer and silicone elastomer, or a mixture of two or more materials.

[0056] Among them, the thermoplastic elastomer is a kind of elastomer that has the elasticity of rubber at normal temperature and can be plastically formed at high temperature, and is a copolymer or a physical mixture of polymers (usually plastics and rubbers), and is composed of materials with thermoplastic and elastomer characteristics. Generally, thermoplastics are relatively easy to use in manufacturing, for example, by injection molding.

[0057] In some embodiments, the powder may also be polypropylene, acrylonitrile butadiene styrene (ABS), polycarbonate (PC), PC-ABS, PLA, polystyrene, lignin, polyamide, polyamide foam, polyamide with additives such as glass or metal particles, methyl methacrylate-acrylonitrile-butadiene-styrene copolymer, absorbable materials such as polymer-ceramic composites, and other similar materials suitable for SLS printing process.

[0058] The 3D printing device may be an SLS type 3D printing device, an SLM type 3D printing device, a DLMD type 3D printing device, an EBM type 3D printing device, an SHS type 3D printing device, etc. In the following embodiments, the 3D printing device being an SLS type 3D printing device will be taken as an example for illustration.

[0059] For an SLS (Selective Laser Sintering) device, its optical system consists of a laser emitter, a flat-field focusing lens, and a galvanometer system. The laser emitter and the galvanometer system are controlled to adjust the energy of the output laser beam. For example, the laser emitter is controlled to emit a laser beam with a preset power and stop emitting the laser beam. Also, for example, the laser emitter is controlled to increase the power of the laser beam and decrease the power of the laser beam. The flat-field focusing lens is used to adjust the focusing position of the laser beam, and the galvanometer system is used to scan the laser beam in the two-dimensional space of the printing reference plane of the powder bed. The powder material scanned by the beam is sintered into a corresponding pattern sintered layer.

[0060] The component platform of the SLS device is arranged in the powder bed or the sintering and forming chamber for containing the powder material, and is used to attach and accumulate the pattern sintered layers irradiated and sintered. After the powder bed is paved with powder, the powder material to be sintered is heated to a certain temperature just below the sintering point of the powder through the temperature control facility in the printing device. The three-dimensional model of the component of the laser tracking printing of the optical system is sliced, and the slice is copied onto the powder bed as a corresponding image, so that the powder material is heated above the melting point under the laser irradiation to achieve sintering, and printing is achieved with the corresponding layer height of the slice. After one layer is constructed, the powder bed descends, and the corresponding next slice pattern is started to be constructed on the existing sintered layer. The above process is repeated until the printing is completed.

[0061] Please refer to Figure 1 , which shows a schematic structural diagram of a 3D printing device in an embodiment of the present application. As Figure 1 shown, the 3D printing device includes a forming platform 1, a powder spreading system 2, an optical system 3, and a control device 4. The forming platform 1 has a forming area (not shown), and a component mechanism 10 that can move layer by layer in the vertical direction is arranged corresponding to the forming area. The powder spreading system 2 is used to spread the powder material in the forming area. The optical system 3 is used to emit a beam of light to irradiate the powder material in the forming area. The control device 4 is connected to the optical system 3, the component mechanism 10, and the powder spreading system 2, and is used to control the powder spreading system 2 to spread the powder material into the forming area during the printing operation, control the optical system 3 to irradiate the powder material in the forming area, and control the component mechanism 10 to move vertically during the printing operation to attach the 3D component formed layer by layer on the component mechanism 10.

[0062] In one embodiment, the optical system may be, for example, the optical system listed in the SLS device described in the foregoing embodiment. Among them, the laser emitter may be a fiber laser, a YAG laser, etc. The galvanometer system can be deflected under the drive of its drive motor. For example, the drive motor of the scanning galvanometer is controlled by the control command output by the control device, and the propagation direction of the light beam is adjusted by adjusting the deflection angle of the scanning galvanometer, so as to accurately position the light beam at any position on the printing reference plane.

[0063] In one embodiment, the control device 4 is an electronic device including a processor. For example, the control device is a computer device, an embedded device, or an integrated circuit integrated with a CPU, such as a control board or a main control board. For example, the control device includes: a processing unit, a storage unit, and a plurality of interface units. Each of the interface units is respectively connected to devices that are independently installed in the 3D printing device such as an optical system, a component mechanism, and a powder spreading system and transmit data through the interface. The control device further includes at least one of the following: a prompting device, a human-computer interaction device, etc. The interface unit determines its interface type according to the connected device, and it includes but is not limited to: a universal serial interface, a video / image interface, an industrial control interface, etc.

[0064] Please refer to Figure 2 , which shows a schematic structural diagram of the forming platform in an embodiment of the present application. As Figure 2 shown, the forming platform 1 has a forming area 11, and a first area 12 and a second area 13 located on opposite sides of the forming area 11. In Figure 2 the example, the first area 12 corresponds to the spatial area on the left side of the forming area 11, and the second area 13 corresponds to the spatial area on the right side of the forming area 11, which is not a limitation on the orientation of the first area 12 and the second area 13.

[0065] It should be noted here that in subsequent embodiments, in order to clearly illustrate the relative positions of various components, structures, components, mechanisms, members, devices, or apparatuses in the printing device, the first area 12 and the second area 13 of the forming platform 1 are used as a reference for distinction. The side of each component, structure, component, mechanism, member, device, or apparatus that is relatively close to the first area 12 is called the first side, and the side that is relatively close to the second area 13 is called the second side. In addition, in view of Figure 2 the example where the first area 12 is on the left side and the second area 13 is on the right side, therefore, in subsequent embodiments, the first side is also called the left side and the second side is also called the right side.

[0066] In one embodiment, the forming platform 1 has a forming chamber, as Figure 2As shown, the forming chamber can be formed by enclosing with an upper housing 17 disposed above the forming platform 1. In some examples, the upper housing 17 can be detachably disposed on the forming platform 1 by means such as screws, snap fasteners, etc. In some examples, the upper housing 17 can be configured with materials having characteristics such as high temperature resistance and high mechanical strength, such as alloys, stainless steels, or carbon fiber composite materials. In some examples, an inert gas can be introduced into the forming chamber for protection so that when the entire printing operation of the 3D printing device is carried out in the forming chamber, the powder can be prevented from oxidizing at high temperatures. On the basis of including layer-by-layer printing operations, the entire printing operation can further include powder spreading operations.

[0067] In one embodiment, as Figure 2 shown, the forming area 11 is set as a spatial area penetrating the forming platform 1. The first area 12 is located on the left side of this spatial area, and the second area 13 is located on the right side of this spatial area. In some examples, the shape of the forming area can be a cube, a cuboid, or other shapes, etc. Its shape and size determine the range within which the 3D device can provide for manufacturing 3D components. For example, if the size of the forming area is 600 mm × 600 mm × 400 mm, then the maximum range within which the 3D printing device can print 3D components is not greater than 600 mm × 600 mm × 400 mm.

[0068] In one embodiment, as Figure 1 shown, the component mechanism 10 corresponding to the forming area 11 is arranged such that the surface of the component faces the forming area 11 to cooperate with the forming area 11 to form a component space. Taking Figure 2 the forming platform 1 shown as an example, the component mechanism 10 is located below the forming area 11 in a manner that can close the bottom opening of the forming area 11, and the top opening of the forming area faces the optical system, so that the component mechanism 10 can jointly form a component space with an opening facing the optical system to receive and emit light beams.

[0069] It should be noted that the component mechanism 10 can be arranged corresponding to the forming area 11 in a fixed manner or detachably. In the embodiment where the component mechanism 10 is detachably arranged at the forming area, the component mechanism can be placed on a transfer mechanism to push the component mechanism 10 away from or dock with the forming area by means of the transfer mechanism. In this example, a docking space can be further arranged at the bottom of the forming platform. When printing is required, the transfer mechanism pushes the component mechanism 10 into the docking space to dock with the forming area for subsequent printing operations. After printing, the transfer mechanism can push the component mechanism 10 away from the docking space to facilitate the operator to perform post-processing operations on the printed 3D component, such as cutting, support removal, grinding and polishing, grinding or sandblasting. In one example, the transfer mechanism can be configured as a cart equipped with rollers.

[0070] In one embodiment, the component mechanism 10 can be configured to include a bin, a component platform, and a Z-axis moving mechanism connected to the component platform. The bin is arranged below the forming area in such a way that its inlet docks with the bottom opening of the forming area. The component platform is arranged in the bin to jointly form a component space for printing 3D components with the bin and the forming area. During printing, the component platform is driven by a Z-axis driving mechanism to move vertically in the bin to adjust the distance from the printing reference plane (which can also be understood as adjusting the volume of the component space), so as to layer by layer accumulate the sintered layers formed by the irradiation of the optical system and finally form a 3D component.

[0071] In one embodiment, the component platform is in close contact with the inner wall of the bin, and its vertical movement driven by the Z-axis driving mechanism during the printing process can be understood as moving up or down in the bin. In some examples, the component plate has a heat conduction function so that the bin and the forming chamber can be maintained in a certain high-temperature environment to optimize the printing quality.

[0072] In one embodiment, the Z-axis driving mechanism includes a driving unit and a Z-axis moving unit. The driving unit is configured to drive the Z-axis moving unit so that the Z-axis moving unit drives the component plate to move along the Z-axis direction. For example, the driving unit is a driving motor. The driving unit is controlled by a control instruction output by the control device. Among them, the control instruction includes: a directional instruction for indicating the rising, falling or stopping of the component plate, and may even include parameters such as rotational speed / rotational acceleration, or torque / torsion. This is beneficial to accurately control the rising distance of the Z-axis moving unit to achieve precise adjustment of the Z-axis. Here, the Z-axis moving unit includes, for example, a fixed rod with one end fixed to the component plate and a bite-type moving component fixed to the other end of the fixed rod. Among them, the bite-type moving component is driven by the driving unit to drive the fixed rod to move along the Z-axis direction. The bite-type moving component is, for example, a limit moving component engaged by a tooth-like structure, such as a rack. Another example is that the Z-axis moving unit includes a lead screw and a positioning moving structure screwed to the lead screw. The two ends of the lead screw are screwed to the driving unit, and the outer extension end of the positioning moving structure is fixedly connected to the component plate. The positioning moving structure may be, for example, a ball screw.

[0073] Please refer to Figure 3 and combine with Figure 2 , where Figure 3 shows a schematic structural diagram of the powder spreading system in an embodiment of the present application. As Figure 2 and Figure 3 shown, the powder spreading system 2 includes a powder spreading device 22, which is configured to be driven to move back and forth between the first area 12 and the second area 13 to perform powder spreading operations on the forming platform 1.

[0074] In one embodiment, each powder spreading operation includes a forward powder spreading operation and a reverse powder spreading operation. Among them, the forward powder spreading operation is defined as the powder spreading operation performed when the powder spreading device 22 moves from the first area towards the second area (in the direction indicated by Y in Figure 2 , which is also called forward movement), and the reverse powder spreading operation is defined as the powder spreading operation performed when the powder spreading device 22 moves from the second position towards the first area (in the direction indicated by X in Figure 2 , which is also called return movement). It should be noted that each powder spreading operation including a forward powder spreading operation and a reverse powder spreading operation is only an example. In other embodiments, each powder spreading operation may also only include a forward powder spreading operation. For example, when performing the return movement, the powder spreading system can be lifted to not contact the forming platform and only perform the return movement without powder spreading. In the following embodiments, each powder spreading operation including a forward powder spreading operation and a reverse powder spreading operation will be taken as an example for description, and it should not be construed as a limitation to the present application.

[0075] In one embodiment, an initial position may be set within the first region 12, and a return position may be set within the second region 13. The powder spreading device 22 may move back and forth between the initial position and the return position to perform the powder spreading operation. That is to say, the movement from the initial position to the return position may be referred to as the forward powder spreading operation, and the movement from the return position to the initial position may be referred to as the reverse powder spreading operation. Among them, the initial position is defined as the starting position when performing the powder spreading operation, and the return position is defined as the end position where the powder spreading device 22 completes the powder laying in one direction starting from the starting position.

[0076] In one embodiment, as Figure 2 shown, a first powder return trough 14 is provided on the first region 12 of the forming platform 1. When the powder spreading device 22 returns and moves within the first region 12, the excess powder can be pushed into the first powder return trough 14. In one example, the first powder return trough 14 is further located on the right side of the initial position. During the reverse powder spreading operation of the powder spreading device 22 and when it moves to the initial position, the powder spreading device 22 will pass by the first powder return trough 14, so that the excess powder can be pushed and dropped into the first powder return trough 14. In this example, the first powder return trough 14 can also be lifted to be flush with the upper surface of the forming platform. During the forward powder spreading operation of the powder spreading device 22, the powder can be smoothly pushed from the first powder return trough 14 to the forming region 11.

[0077] Further, please refer to Figure 4 and Figure 5 , which respectively show schematic diagrams of the first powder return trough in one embodiment of the present application. As Figure 4 and Figure 5 shown, the first powder return trough 14 includes a trough bottom plate 142 connected to the first lifting assembly 141. The trough bottom plate 142 is driven by the first lifting assembly 141 to a first position P1 flush with the forming platform 1 for the powder spreading device 22 to pass through when moving to the second region 13, and after the powder spreading device 22 passes through the trough bottom plate 142, it is driven by the first lifting assembly 141 to sink below the forming platform 1 to a second position P2 for powder receiving. That is to say, the first lifting assembly 141 can drive the trough bottom plate 142 to perform a lifting movement, so that when the trough bottom plate 142 is at the first position P1, it allows the powder spreading device 22 to pass through for the forward powder spreading operation. When the trough bottom plate 142 is at the second position P2, it allows the powder spreading device 22 to receive the excess powder generated during the reverse powder spreading operation.

[0078] In one embodiment, the first position P1 is flush with the upper surface of the forming platform 1. On the one hand, it can enable the powder spreading device 22 to pass through unobstructed during the forward powder spreading operation. On the other hand, it can push the powder falling in the first powder return trough 14 onto the upper surface of the forming platform to supplement the powder amount during the forward powder spreading operation of the powder spreading device. The second position P2 can be set at the bottom of the first powder return trough 14 to form a space S capable of accommodating powder, so as to facilitate the powder spreading device 22 to push the excess powder into the space S during the reverse powder spreading operation. It should be understood that the volume provided by the space S determines the maximum capacity of the first powder return trough 14 to receive powder. In this embodiment, the first lifting assembly 141 can drive the trough bottom plate 142 to move to the first position P1 or the second position P2, respectively presenting as Figure 4 and Figure 5 states.

[0079] In one embodiment, the first lifting assembly 141 is arranged on the lower side of the trough bottom plate 142, and it can be configured to include a first lifting shaft and a first lifting driving part. The first lifting shaft is connected to the trough bottom plate 142, and the first lifting driving part can be arranged at the bottom of the first lifting shaft and associated with the first lifting shaft, for example, to move the trough bottom plate 142 to the first position P1 or the second position P2.

[0080] In some examples, the first lifting shaft can be configured as a threaded rod, and the first lifting driving part can be configured as a rotary motor. For example, driving the threaded rod to rotate forward by the rotary motor can realize the upward movement of the trough bottom plate 142, and driving the threaded rod to rotate reversely by the rotary motor can realize the downward movement of the trough bottom plate 142. In some other examples, the first lifting shaft can be configured as a telescopic rod, and the first lifting driving part can be configured as a lifting motor. For example, driving the telescopic rod to stretch by the lifting motor can realize the upward movement of the trough bottom plate 142, and driving the telescopic rod to retract by the lifting motor can realize the downward movement of the trough bottom plate 142. Of course, in some other embodiments, the first lifting assembly 141 can also be configured in other forms as long as it can drive the trough bottom plate 142 to move up and down. In some examples, the first lifting assembly 141 can also include a limiting part to prevent the trough bottom plate 142 from moving excessively when rising to the first position P1 or falling to the second position P2.

[0081] In one embodiment, as Figure 2As shown, a second powder return trough 15 is provided on the second region 13 of the forming platform 1. In one example, the second powder return trough 15 is further located on the left side of the return position. When the powder spreading device 22 moves from the initial position towards the return position to complete the forward powder spreading operation, the excess powder can be sent to the second powder return trough 15. In this example, the second powder return trough 15 can also be lifted to be flush with the upper surface of the forming platform. During the reverse powder spreading operation of the powder spreading device 22, the powder can be smoothly pushed from the second powder return trough 15 to the forming area 11.

[0082] In one embodiment, the second powder return trough 15 can be configured to have the same structure as the first powder return trough 14, that is, the second powder return trough 15 can include a trough bottom plate connected to the second lifting assembly. Among them, the second lifting assembly can also be configured to have the same structure as the first lifting assembly 141. For specific details, reference can be made to the description of the first powder return trough 14 in the foregoing embodiment, which will not be elaborated here.

[0083] Specifically, the trough bottom plate of the second powder return trough 15 is driven by the second lifting assembly to sink to the second position P2 of the forming platform 1 to receive the powder pushed in when the powder spreading device 22 moves to the second region 13, and after the powder spreading device 22 passes the trough bottom plate, it is driven by the second lifting assembly to be flush with the forming platform 1 at the first position P1 to lift the received powder to the forming platform.

[0084] The following combines Figure 2 、 Figure 4 、and Figure 5 The process of completing a powder spreading operation is described as follows. The powder spreading device 22 first moves from the initial position towards the return position to perform the forward powder spreading operation. At this time, the first lifting assembly 141 drives the trough bottom plate 142 of the first powder return trough 14 to rise to the first position P1 so that the powder spreading device 22 passes through and continues to pass through the forming area 11 to spread powder in the forming area 11. Before the powder spreading device 22 moves to the second powder return trough 15, the second lifting assembly drives the trough bottom plate of the second powder return trough 15 to descend to the second position P2 to recover the excess powder until the powder spreading device 22 moves to the return position to complete the forward powder spreading operation. When the powder spreading device 22 moves from the return position towards the initial position to perform the reverse powder spreading operation, the second lifting assembly drives the trough bottom plate of the second powder return trough 15 to rise to the first position P1 so that the powder spreading device 22 passes through and continues to pass through the forming area 11 to continue spreading powder in the forming area 11. Before the powder spreading device 22 moves to the first powder return trough 14, the first lifting assembly 141 drives the trough bottom plate 142 of the first powder return trough 14 to descend to the second position P2 to recover the excess powder until the powder spreading device 22 moves to the initial position to complete the reverse powder spreading operation.

[0085] In one embodiment, as Figure 2As shown, the first region 12 is also provided with an overflow powder port 16 located on the first side of the first powder return trough 14. As described above, the volume provided by the space S in the first powder return trough 14 determines the maximum capacity of the first powder return trough 14 to receive powder. Therefore, if the amount of excess powder during one powder spreading operation by the powder spreading device 22 is greater than the maximum capacity of the first powder return trough 14, the powder spreading device 22 will continue to drive the excess powder exceeding the maximum capacity of the first powder return trough 14 towards the overflow powder port 16 when passing through the first powder return trough 14, so as to recover the excess powder by means of the overflow powder port 16. Further, in some examples, a powder recovery mechanism may be provided under the overflow powder port 16 to recover the excess powder.

[0086] The powder spreading operation described in this application may be the powder spreading operation in the leveling stage or the powder spreading operation in the printing stage. Among them, the leveling stage refers to the process of filling the bottom surface in the forming area before formal printing, and the printing stage refers to the process of forming the powder layer by layer by using the emitted light beam of the optical system to construct a 3D component layer by layer.

[0087] It should be noted that the powder spreading operation in the leveling stage is closely related to the quality of the printed 3D component. For example, if printing starts before the leveling stage is completed, it will cause pores or cracks in the 3D component. However, in the related art, usually the operator uses the naked eye to judge whether the leveling stage is completed, and this method has low efficiency and poor accuracy. In addition, in the powder spreading operation in the printing stage, quantitative powder supply is usually adopted, which cannot adjust the powder supply amount in time according to parameters such as the thickness of the printing layer and the printing speed, and will cause problems such as excessive waste of powder supply or insufficient supply to ensure the smooth progress of the printing process.

[0088] In view of this, in one embodiment, as Figure 2 shown, the powder spreading system 2 described in this application further includes a powder return detection mechanism 23. The powder return detection mechanism 23 is arranged on the upper side of the first powder return trough 14 and is used to detect the powder surface distance of the first powder return trough 14 when the powder spreading device 22 completes one round-trip movement to determine whether the leveling stage of the forming platform 1 is completed or to determine the powder supply amount for the next powder spreading operation. Among them, the setting of the powder return detection mechanism 23 on the upper side of the first powder return trough 14 means that it can be located in any area above the first powder return trough 14, and it does not necessarily need to be directly above the first powder return trough 14.

[0089] In one embodiment, the powder return detection mechanism 23 is disposed at the top of the upper housing 17 to project a laser beam towards the first powder return trough 14 to detect the powder surface distance. In one example, a first opening is provided on the upper housing 17, and the powder return detection mechanism 23 is fixed to the upper housing in such a way that its emitting portion faces the opening, so as to allow the laser beam projected by the powder return detection mechanism 23 to pass through the upper housing 17 and enter the first powder return trough 14, thereby realizing the detection of the powder surface distance. In this example, a second opening may also be provided on the upper housing 17 for disposing the optical system 3 and allowing the light beam emitted by the optical system 3 to pass through and be projected onto the forming area 11.

[0090] In one embodiment, the powder surface distance is reflected by the length of the laser beam emitted by the powder return detection mechanism 23 towards the first powder return trough 14. Please refer to Figure 6 , which shows a schematic diagram of the powder return detection mechanism detecting the powder surface distance in one embodiment of the present application. Figure 6 In, the powder return detection mechanism 23 is indicated by small dots, and the laser beam emitted by the powder return detection mechanism 23 is indicated by a straight line extending from the small dots. In the example shown in Figure 6 , the powder surface distance corresponds to the length L of the emitted laser beam. It should be noted that the surface of the powder in the first powder return trough 14 is not necessarily an inclined surface as shown in Figure 9 . Due to the randomness of the powder falling into the first powder return trough 14, the surface of the accumulated powder can be of any shape, such as an arc shape or an irregular shape. In these examples, the powder surface distance is the length L of the laser beam.

[0091] The following will be described in detail with reference to Figures 7 to 10 how the powder return detection mechanism 23 is used to determine whether the leveling stage of the forming platform 1 is completed.

[0092] Please refer to Figure 7 , which shows a schematic diagram of the forming area before the leveling stage in one embodiment of the present application. As shown in Figure 7 , the powder in the forming area 11 is uneven. For example, there may be pits, local accumulations or vacancies on the powder layer, so leveling is required. Please refer to Figure 8 , which shows a schematic diagram of the powder spreading operation in the leveling stage in one embodiment of the present application. As shown in Figure 8 , when the powder spreading device 22 performs the first forward powder spreading operation, the amount of powder can be spread to the position of M1. At this time, all the powder is pushed towards the forming area 11 and is not enough to completely fill the pits or vacancies on the powder layer therein. Therefore, no excess powder will be pushed into the first powder return trough 14 during the reverse powder spreading operation. As shown in Figure 8As shown, during the second, third, fourth, and fifth powder spreading operations, the powder amount can be allowed to spread to the positions of M2, M3, M4, and M5 respectively. Only by performing multiple powder spreading operations in this way can the forming area 11 be leveled.

[0093] According to the different powder amounts or filling areas, the number of powder spreading operations required for the powder spreading device 22 to complete leveling is uncertain. In view of this, in some embodiments of the present application, determining whether the leveling stage of the forming platform 1 is completed includes determining that the forming platform has been leveled when there is powder in the first powder return tank 14 based on the powder surface distance L measured by the powder return detection mechanism 23.

[0094] In one embodiment, it is possible to determine whether there is powder in the first powder return tank 14 based on the measured powder surface distance L and a reference distance. Among them, the reference distance can be determined by means of a lower limit distance of the tank, so as to Figure 5 Combine Figure 9 Shown as an example, Figure 9 It shows a schematic diagram of the powder return detection mechanism detecting the lower limit distance of the tank in one embodiment of the present application. The lower limit distance of the tank is the laser length L2 when the tank bottom plate 142 is located at the second position P2. In some examples, the reference distance can be set as the lower limit distance of the tank, or slightly less than the lower limit distance of the tank. When the powder surface distance L is less than the reference distance, that is, the powder has exceeded the second position P2, it can be determined that there is powder in the first powder return tank 14, that is, it can be determined that the forming area has been leveled. The leveled state is as shown in Figure 10 Shown, Figure 10 It shows a schematic diagram of the forming area in one embodiment of the present application after leveling is completed. In this way, the subsequent printing stage can be entered.

[0095] The following combines Figure 11 To describe in detail how the powder return detection mechanism 23 is used to determine the powder supply amount for the next powder spreading operation.

[0096] Please refer to Figure 11 , which shows a schematic diagram of the powder spreading operation in the printing stage in one embodiment of the present application. As shown in Figure 11 Shown, after leveling is completed, the aforementioned component board can be lowered by the height of one printing layer under the drive of the Z-axis drive mechanism. At this time, the powder spreading device 22 performs a powder spreading operation under the control of the control device, and the powder can be evenly laid in the forming area 11. Then, the optical system can emit a beam to form the powder layer.

[0097] In order to ensure that the powder feeding amount can be adapted to the powder spreading amount of each layer, the powder return detection mechanism 23 can be used to detect the powder surface distance L of the first powder return tank 14 when the powder spreading device 22 completes a round trip movement, so as to determine the powder supply amount for the next powder spreading operation. Specifically, when the detected powder surface distance L indicates that the powder supply amount for the current powder spreading operation is relatively large, the powder supply amount for the next powder spreading operation should be reduced; when the detected powder surface distance L indicates that the powder supply amount for the current powder spreading operation is relatively small, the powder supply amount for the next powder spreading operation should be increased. In some implementation manners, the adjustment of the powder supply amount can be achieved through the control device. For example, the control device can generate a control instruction for adjusting the powder supply amount based on the powder surface distance L, and control a powder supply component in the powder spreading system 2 to adjust the powder supply amount according to the control instruction. In some examples, the adjustment of the powder supply amount can be achieved by adjusting the quality or frequency of the powder supplied by the powder supply component. In some examples, the powder supply component can be configured to include a storage bin and a screw feeder that provides power for powder supply.

[0098] In one embodiment, the powder supply amount for the next powder spreading operation can be determined based on the measured powder surface distance L and a reference powder surface distance range. For example, when the measured powder surface distance L is less than the minimum value of the reference powder surface distance range, the powder supply amount for the next powder spreading operation can be reduced; when the measured powder surface distance L is greater than the maximum value of the reference powder surface distance range, the powder supply amount for the next powder spreading operation can be increased; when the measured powder surface distance L is within the reference powder surface distance range, the powder supply amount for the next powder spreading operation can be not adjusted.

[0099] In one embodiment, the reference powder surface distance range can be determined based on a tank lower limit distance and a tank upper limit distance. Among them, both the tank lower limit distance and the tank upper limit distance can be detected by the powder return detection mechanism 23. As shown in Figure 4 、 Figure 5 、and Figure 9 shown, the powder return detection mechanism 23 can detect the corresponding tank upper limit distance L1 when the tank bottom plate 142 is at the first position P1 and the corresponding tank lower limit distance L2 when the tank bottom plate 142 is at the second position P2 respectively.

[0100] Specifically, when determining the reference powder surface distance interval, a reference value can be first determined based on the lower slot distance L2 and the upper slot distance L1, and then the reference powder surface distance interval can be obtained from the reference value. For example, the reference value can be the average value of the lower slot distance L2 and the upper slot distance L1, and the reference powder surface distance interval is this average value or a numerical interval expanded up and down with this average value as the reference value. For example, when the upper slot distance L1 is 50 mm and the lower slot distance L2 is 100 mm, the average value of the two is 75 mm. Taking this average value as the reference powder surface distance interval is 75 mm, and expanding 5% up and down with this average value as the reference value is [71.25, 78.75].

[0101] Please refer to Figures 12 to 14 , in which Figure 12 and Figure 13 respectively show the schematic structural diagrams of the powder return detection mechanism in different perspectives in an embodiment of the present application, Figure 14 shows the cross-sectional schematic diagram of the powder return detection mechanism in an embodiment of the present application. As Figures 12 to 14 shown, the powder return detection mechanism 23 includes a base 231 and a rangefinder 232. The base 231 is disposed on the top of the upper housing 17 and has a light channel 2311 that penetrates up and down to communicate with the molding chamber. The rangefinder 232 is disposed on the base 231 to project laser light toward the first powder return groove 14 through the light channel 2311 and receive the reflected light. In order to distinguish it from the base 221 included in the powder spreading device 22 in the subsequent embodiments, the base 231 included in the powder return detection mechanism 23 can be referred to as the first base, and the base 221 included in the powder spreading device 22 can be referred to as the second base. The subsequent mention of the first base 231 and the second base 221 will not be repeated.

[0102] In an embodiment, the rangefinder 232 is configured as a laser rangefinder sensor, including a transmitting part and a receiving part. The transmitting part is used to project laser light toward the first powder return groove 14 through the light channel 2311, and the receiving part is used to receive the light reflected back from the first powder return groove 14 by the laser.

[0103] Please refer to Figure 15 , which shows the exploded structural schematic diagram of the first base in an embodiment of the present application. As Figure 15 shown, the first base 231 includes a substrate 2312 and a seat body 2313 fixed to the top of the upper housing 17. The substrate 2312 has an inclined mounting surface 23121, and the seat body 2313 is mounted on the mounting surface 23121 so that the rangefinder 232 located on the seat body 2313 is located on the top of the upper housing 17 in an inclined posture. In an example, the seat body 2313 is mounted on the mounting surface 23121 through an elbow clamp. In this example, please combine Figure 14, the optical channel 2311 includes a lower opening 23111 formed in the substrate 2312 and an upper opening 23112 formed in the base body 2313. The lower opening 23111 and the upper opening 23112 communicate with each other to ensure that the laser projected into the first powder return tank 14 is not blocked.

[0104] In one embodiment, as Figure 15 shown, the base body 2313 is generally rectangular, and the substrate 2312 is generally trapezoidal. Its lower surface is parallel to the upper shell 17, and its upper surface has an inclined angle to form the mounting surface 23121, so that the base body 2313 is inclinedly arranged on the substrate 2312, thereby realizing the inclined arrangement of the rangefinder 232 relative to the upper shell 17, so that the laser can be inclinedly projected into the first powder return tank 14 from the optical channel 2311.

[0105] It should be understood that devices or components such as a powder spreading device 22 or an optical system will be arranged in the forming chamber. The inclined arrangement of the rangefinder 232 can prevent the laser emitted by it from being blocked by these devices or components, so that the laser light path can bypass obstacles and be directly projected into the first powder return tank 14. In addition, if the laser projected by the rangefinder 232 is vertically projected onto the first powder return tank 14, it will affect the reception of the reflected light by the receiving part. Therefore, the inclined posture of the rangefinder 232 can ensure the continuity of the light path and at the same time ensure the accuracy of the obtained reflected light signal.

[0106] It should be noted that the high-temperature environment in the forming chamber will also affect the normal operation of the rangefinder 232. In view of this, in one embodiment, as Figure 12 shown, the powder return detection mechanism 23 further includes a cooling mechanism 233 arranged on the first base 231. The cooling mechanism 233 is attached to the rangefinder 232 to cool it down. In some examples, the cooling mechanism 233 can use coolant or gas to cool the rangefinder 232.

[0107] In one embodiment, the cooling mechanism 233 includes at least one cooling body having an inlet and an outlet. A cooling passage communicating the inlet and the outlet is arranged in the cooling body for the coolant to pass through.

[0108] In one embodiment, the cooling bodies are arranged as two respectively attached to opposite side walls of the rangefinder 232. Please refer to Figure 12 and Figure 14 , the two cooling bodies are respectively attached to the first side and the second side of the rangefinder 232 to achieve sufficient cooling of the rangefinder 232. For the convenience of distinction, as Figure 12 shown, the cooling body arranged on the first side of the rangefinder 232 is called the first cooling body 2331, and the cooling body arranged on the second side of the rangefinder 232 is called the second cooling body 2332.

[0109] Of course, in some other embodiments, the cooling body can also be configured as one or more than two, for example, cooling bodies can be provided on the four side walls around the rangefinder 232, or configured as a single integrated cooling body that fits the four side walls respectively. In some examples, the material of the cooling body can be configured as a metal with good thermal conductivity such as copper or aluminum.

[0110] Please refer to Figure 16 , which shows a cross-sectional schematic diagram of the cooling mechanism in an embodiment of the present application. Taking the first cooling body 2331 as an example, as Figure 16 shown, the first cooling body 2331 has a first liquid inlet 23311 and a first liquid outlet 23312, and a first cooling passage 23313 communicating the first liquid inlet 23311 and the first liquid outlet 23312 is provided in the first cooling body 2331 for the coolant to pass through. That is, the coolant flows through the first cooling passage 23313 through the first liquid inlet 23311, so that the overall temperature of the first cooling body 2331 is reduced, and then the first cooling body 2331 exchanges heat with the rangefinder 232 to achieve cooling of the rangefinder 232, and then is output from the first cooling body 2331 through the first liquid outlet 23312. In some examples, the shape of the first cooling passage 23313 can be configured as slender and tortuous to increase the contact area between the coolant and the first cooling body 2331, thereby improving the cooling efficiency. In some examples, the coolant can be configured as water or ethylene glycol solution, etc.

[0111] In an embodiment, the first liquid inlet 23311 and the first liquid outlet 23312 can be flexibly configured. In one example, the first liquid inlet 23311 and the first liquid outlet 23312 can be configured as an inlet and an outlet to be respectively used as the interfaces for the coolant to enter and exit the first cooling body 2331. In another example, the first liquid inlet 23311 and the first liquid outlet 23312 can also be respectively configured as a section of pipeline extending from the first cooling body 2331 to facilitate the transition connection between the pipelines. In some other examples, it can also be configured in a form combining an interface and a pipeline to meet the conveying requirements of the coolant.

[0112] In an embodiment, the cooling mechanism 233 further includes a circulating liquid supply mechanism (not shown), and each cooling body is connected in series between the inlet pipeline and the outlet pipeline of the circulating liquid supply mechanism. Taking the cooling body configured to include the first cooling body 2331 and the second cooling body 2332 as an example, please refer to Figure 17 , which shows a schematic diagram of each cooling body connected in series in an embodiment of the present application. As Figure 17As shown, a first liquid inlet 23311 and a first liquid outlet 23312 are provided on the first cooling body 2331, and a second liquid inlet 23321 and a second liquid outlet 23322 are provided on the second cooling body 2332. In one example, the liquid inlet pipeline is communicated with the first liquid inlet 23311, and the liquid outlet pipeline is communicated with the second liquid outlet 23322. In this example, the flow path C of the coolant is as shown by the arrow in Figure 17 Specifically, the coolant is input from the liquid inlet pipeline to the first liquid inlet 23311, output from the cooling passage in the first cooling body 2331 to the first liquid outlet 23312, then input to the cooling passage of the second cooling body 2332 through the second liquid inlet 23321 communicated with the first liquid outlet 23312, and finally output to the liquid outlet pipeline through the second liquid outlet 23322.

[0113] In another embodiment, each cooling body is connected in parallel between the liquid inlet pipeline and the liquid outlet pipeline of the circulating liquid supply mechanism. Still taking the cooling bodies configured to include the first cooling body 2331 and the second cooling body 2332 as an example, please refer to Figure 18 which shows a schematic diagram of each cooling body connected in parallel in an embodiment of the present application. As shown in Figure 18 a first liquid inlet 23311 and a first liquid outlet 23312 are provided on the first cooling body 2331, and a second liquid inlet 23321 and a second liquid outlet 23322 are provided on the second cooling body 2332. In one example, the liquid inlet pipeline is respectively communicated with the first liquid inlet 23311 and the second liquid inlet 23321, and the liquid outlet pipeline is respectively communicated with the first liquid outlet 23312 and the second liquid outlet 23322. In this example, the flow path of the coolant includes a first flow path B1 and a second flow path B2 connected in parallel, and specifically is as shown by the arrow in Figure 18 That is, the coolant is simultaneously input from the liquid inlet pipeline to the first liquid inlet 23311 and the second liquid inlet 23321 to enter the first cooling body 2331 and the second cooling body 2332 at the same time. After flowing through their respective cooling passages, it is then output to the liquid outlet pipeline through the first liquid outlet 23312 and the second liquid outlet 23322. In this embodiment, the liquid inlet pipeline and the liquid outlet pipeline can be selectively configured as one or two.

[0114] It should be understood that during the powder spreading stage and the printing stage, some powder in the forming chamber may be lifted to form dust. When the density of the dust is too high, it may hinder the receiving part of the rangefinder 232 from receiving the reflected light signal, thereby reducing the measurement accuracy. In view of this, in one embodiment, please combine Figure 14 and Figure 15, as shown in the figure, the upper opening 23112 of the optical channel 2311 covers a light-transmitting protection plate 23113, and the rangefinder 232 is located on the light-transmitting protection plate 23113. In this embodiment, the light-transmitting protection plate 23113 can serve as a physical barrier to block the powder, thereby ensuring the measurement accuracy. In some examples, the light-transmitting protection plate 23113 can be configured as a plexiglass plate. In some examples, an anti-reflection coating can be applied to the surface of the light-transmitting protection plate 23113 to reduce the reflection loss of the laser on the surface of the light-transmitting protection plate 23113.

[0115] In one embodiment, as Figure 14 shown, a gas guiding structure 2314 communicating with the upper opening 23112 is formed in the first base 231. The gas guiding structure 2314 is used to direct the airflow from the cleaning mechanism to the lower side of the light-transmitting protection plate 23113 to clean the light-transmitting protection plate 23113. In this embodiment, the airflow of the cleaning mechanism can clean the dirt attached to the light-transmitting protection plate to avoid affecting the reception of the reflected light signal by the rangefinder 232. In one example, the cleaning work may include a first cleaning work, that is, using the airflow generated by the gas guiding structure 2314 to clean the stubborn dirt attached to the light-transmitting protection plate 23113. Among them, the stubborn dirt refers to, for example, the oil mist formed by the evaporation of the lubricating oil in the powder spreading device in the high-temperature environment in the forming chamber or the paste formed by the combination of the oil mist and the powder. In another example, the cleaning work may include a second cleaning work, that is, using the airflow generated by the gas guiding structure 2314 to clean the powder attached to the light-transmitting protection plate 23113.

[0116] Please refer to Figure 19 and Figure 20 , where Figure 19 shows a schematic diagram of the gas guiding structure in one embodiment of the present application, Figure 20 shows as Figure 19 the cross-sectional schematic diagram of the gas guiding structure in the shown embodiment. As Figure 19 and Figure 20 shown, the gas guiding structure 2314 includes a first air inlet channel 23141, a buffer chamber 23142, and an air outlet channel 23143 that are sequentially connected. Please refer to Figure 21 , which shows as Figure 19 the partial enlarged schematic diagram of the gas guiding structure in the shown embodiment. As Figure 21 shown, the airflow fills the buffer chamber 23142 through the first air inlet channel 23141 and continues to enter the air outlet channel 23143 to form a high-speed airflow F.

[0117] In one embodiment, as Figures 19 to 21As shown, the buffer chamber 23142 is provided as a groove opened in the adjacent area of the optical channel 2311, and the air outlet channel 23143 is provided as being formed by sinking in a preset area connected between the opening of the groove and the upper opening 23112. Wherein, the preset area refers to an area pre-defined in the connection area between the opening of the groove corresponding to the buffer chamber 23142 and the upper opening 23112. For example Figure 20 The outer contour of the air outlet channel 23143 shown in corresponds to the pre-defined area. It should be noted that the height of the sinking of the preset area (i.e., the height of the air outlet channel 23143) is much smaller than the height of the buffer chamber 23142, so that the cross-sectional area of the air flow flowing into the air outlet channel 23143 is sharply reduced, thereby facilitating the formation of the high-speed air flow F.

[0118] In one embodiment, as Figure 19 shown, the air outlet channel 23143 includes a transition section T1 communicating with the buffer chamber 23142 and an air outlet section T2 communicating with the upper opening 23112. The transition section T1 is used to introduce the air flow into the air outlet section T2, and the width of the air outlet section T2 is not less than the width of the upper opening 23112 so that the air flow guided out by the air outlet section T2 can completely cover the upper opening 23112. In this example, the transition section T1 is provided as a part similar to a horn shape as shown in Figure 19 to expand the air flow, and the air outlet section T2 is provided as a rectangular part as shown in Figure 19 to guide the air flow to the optical channel 2311.

[0119] In one embodiment, the first air inlet channel 23141 is used to communicate with the first cleaning component in the cleaning mechanism to perform the first cleaning work. Wherein, the first cleaning component can be configured to include a gas compressor for inputting high-pressure gas into the first air inlet channel 23141 to perform the first cleaning work. In one example, the gas can be configured to be the same gas as the inert gas in the molding chamber, such as nitrogen, to ensure the molding environment in the molding chamber. In this embodiment, the first cleaning component can input gas into the first air inlet channel 23141 at intervals, that is, the first cleaning component for stubborn dirt such as oil mist attached to the light-transmitting protection plate works intermittently, and its working frequency can be, for example, once a day.

[0120] Please refer to Figure 22 , which shows a schematic diagram of the gas guiding structure in another embodiment of the present application. As Figure 22As shown, the gas guiding structure 2314 further includes a second intake passage 23144 communicating with the buffer chamber 23142. The second intake passage 23144 is used to communicate with a second cleaning assembly in the cleaning mechanism to perform a second cleaning operation. Among them, the second cleaning assembly can be configured as an air pump for inputting inert gas into the second intake passage 23144 to perform the second cleaning operation. In this embodiment, the second cleaning assembly can work continuously to continuously blow a gas flow under the light-transmitting protection plate 23113, thereby preventing powder from adhering to the light-transmitting protection plate 23113. In some examples, the static pressure of the gas under the light-transmitting protection plate 23113 can reach 50324 Pa.

[0121] In one embodiment, as Figure 3 shown, the powder spreading device 22 includes a second base 221 and a powder spreading assembly. The second base 221 is disposed in the forming chamber and is connected to a powder spreading driving mechanism. In one example, the powder spreading driving mechanism is configured to include a first driving mechanism and a second driving mechanism. In this example, the second base 221 is used to be driven by the first driving mechanism to move back and forth between the first area 12 and the second area 13. The powder spreading assembly includes a powder spreading roller 2211 disposed on the second base 221. The powder spreading roller 2211 is connected to the second driving mechanism so that it is driven to rotate by the second driving mechanism when following the second base 221 to move back and forth to spread the powder on the forming platform 1.

[0122] In one embodiment, as Figure 3 shown, the powder spreading roller 2211 is disposed below the second base 221, and its axis is perpendicular to its translation direction. In this embodiment, the second base 221 serves as a supporting structure for supporting the powder spreading roller 2211 and can be configured with rigid materials such as alloy and stainless steel to provide rigid support for the powder spreading roller 2211, reducing the uneven powder spreading phenomenon caused by the vibration of the powder spreading roller during the powder spreading process. In one example, the powder spreading roller 2211 can apply a certain pressure to the powder during the movement to reduce the gap between the powders in the layers and improve the compactness of the spread powder, avoiding printing defects such as holes or warping caused by loose powder. In one example, the powder spreading roller 2211 is configured with high-hardness and wear-resistant materials such as hardened steel, composite ceramics or carbon fiber composite materials to resist the frictional loss with the powder.

[0123] In one embodiment, the first driving mechanism can drive the powder spreading roller 2211 to perform a reciprocating translational motion between the initial position and the return position, and the second driving mechanism can drive the powder spreading roller 2211 to rotate counterclockwise or clockwise around its axis while performing the translational motion to achieve forward powder spreading operation or reverse powder spreading operation. Specifically, when performing the forward powder spreading operation, the first driving mechanism drives the powder spreading roller 2211 to translate from the initial position towards the return position. At the same time, the second driving mechanism drives the powder spreading roller 2211 to rotate counterclockwise around its axis. When performing the reverse powder spreading operation, the first driving mechanism drives the powder spreading roller 2211 to translate from the return position towards the initial position. At the same time, the second driving mechanism drives the powder spreading roller 2211 to rotate clockwise around its axis.

[0124] In one implementation manner, the first driving mechanism is configured to include a first driving guide rail and a first driving unit. Among them, the first driving guide rail is arranged on the forming platform 1 along the linear movement direction of the powder spreading operation. In one example, the first driving unit may include a translation lead screw and a translation motor, and the translation lead screw is associated with the powder spreading roller 2211. The translation motor and the translation lead screw can be used to drive the powder spreading roller 2211 to perform a reciprocating translational motion between the initial position and the return position. For example, when the translation motor drives the translation lead screw to rotate forward, it can drive the powder spreading roller 2211 to perform a forward powder spreading operation from the initial position towards the return position; when the translation motor drives the translation lead screw to rotate in reverse, it can drive the powder spreading roller 2211 to perform a reverse powder spreading operation from the return position towards the initial position. In some other implementation manners, the first driving mechanism can also be configured as a cylinder with a telescopic rod, but not limited thereto, as long as it can drive the powder spreading roller 2211 to move linearly.

[0125] In one implementation manner, the second driving mechanism can be configured to include a rotating shaft and a second driving source. The rotating shaft is arranged on the axis of the powder spreading roller 2211, and the second driving source is associated with the rotating shaft for driving the powder spreading roller 2211 to rotate counterclockwise or clockwise. In one example, the second driving source is configured as a rotating motor.

[0126] As described above, to prevent the powder spreading roller from causing uneven subsequent powder spreading due to the powder adhering to it during powder spreading, it is necessary to clean the powder spreading roller in the powder spreading device in a timely manner. In some related technologies, a brush is usually used to scrape the residual powder on the powder spreading roller. However, the cleaning force of the brush is limited, and it can only scrape off large-particle powder. Small-particle powder or viscous powder adhering to it may remain in the bristles and cannot be scraped off, thus affecting the subsequent powder spreading process. In addition, in some related technologies, a flexible member is used to scrape the residual powder on the powder spreading roller. However, due to the soft material of the flexible member, some powders with a certain hardness will be embedded in it. As the powder spreading roller rotates, these harder powders will cause scratches on the surface of the powder spreading roller, which will affect the service life of the powder spreading roller.

[0127] In view of this, please refer to Figures 35 to 38 , in which, Figure 35 and Figure 36 respectively show schematic cross-sectional views of the powder spreading device in different perspectives in an embodiment of the present application, Figure 37 and Figure 38 respectively show schematic cross-sectional views of the powder spreading device in different perspectives in another embodiment of the present application. As Figures 35 to 38 shown, the powder spreading device 22 provided by the present application further includes a scraper assembly 24. The scraper assembly 24 is disposed on the second base 221 and includes at least one scraper 241 disposed along the length direction of the powder spreading roller 2211 and in contact with the powder spreading roller 2211. The scraper 241 is used to scrape the powder adhering to the powder spreading roller 2211 in cooperation with the rotation of the powder spreading roller 2211. The scraper assembly 24 provided by the present application can use the scraper 241 to entirely fit on the surface of the powder spreading roller 2211, thereby preventing the powder from remaining. In addition, the design of the scraper 241 can also prevent powders with a certain hardness from being embedded in it, thereby avoiding scratches on the powder spreading roller.

[0128] In one embodiment, the length of the scraper 241 is greater than the length of the powder spreading roller 2211 to ensure that the cleaning area of the scraper 241 can completely cover the surface area of the powder spreading roller 2211 when the powder spreading roller 2211 rotates.

[0129] In one embodiment, the powder spreading roller 2211 has a first stiffness, and the scraping blade 241 has a second stiffness, and the second stiffness is greater than the first stiffness. Herein, the stiffness refers to the ability of the powder spreading roller 2211 or the scraping blade 241 to resist elastic deformation when subjected to force, which is used to characterize the difficulty of deformation of the powder spreading roller 2211 or the scraping blade 241, and can also be understood as the relative hardness of the powder spreading roller 2211 or the scraping blade 241. In this embodiment, the fact that the stiffness of the scraping blade 241 is greater than that of the powder spreading roller 2211 can be understood as the hardness of the scraping blade 241 being greater than that of the powder spreading roller 2211, which enables the scraping blade 241 to clean the powder spreading roller 2211 more thoroughly. For example, it can further scrape off the powder with strong adhesion that is melted or sintered during the forming process. In one example, the powder spreading roller 2211 is configured to be made of stainless steel, and the scraping blade 241 is configured to be made of tungsten steel, but this is not limited thereto, as long as the stiffness of the scraping blade 241 is greater than that of the powder spreading roller 2211.

[0130] In one embodiment, please refer to Figure 2 and Figures 35 to 38 , the second base 221 includes a main frame 2212 and side support plates 2213 arranged on the lower side of the main frame 2212. The main frame 2212 spans the forming area 11 opened on the forming platform 1 and is connected to the first driving mechanism. The powder spreading roller 2211 is arranged along the length direction of the main frame 2212 and is mounted on the first mounting portion on the side support plates 2213.

[0131] In one implementation manner, the main frame 2212 can be integrally presented in a portal shape so as to support components such as the powder spreading roller 2211 and the scraping blade 241 while being movable on the forming platform 1. In one example, the main frame 2212 can be configured to include a transverse plate and two longitudinal plates. Taking Figure 35 and Figure 37 the interconnected one transverse plate 22121 and one longitudinal plate 22122 shown as an example, as Figure 35 and Figure 37 shown, a reinforcing portion 22120 is provided at the connection of the transverse plate 22121 and the longitudinal plate 22122 to make the connection between the transverse plate 22121 and the longitudinal plate 22122 more stable. At Figure 35 and Figure 37In the illustrated example, the side support plate 2213 is disposed on the lower side of the transverse plate 22121 to mount the powder spreading roller 2211. At this time, there is a certain gap between the powder spreading roller 2211 and the transverse plate 22121 to prevent interference with the rotation of the powder spreading roller 2211. In the example where the first driving mechanism is configured to include a first driving guide rail, the longitudinal plate 22122 can be connected to the first driving guide rail to enable the first driving mechanism to drive the second base 221 to move on the forming platform 1. In one example, the first mounting portion can be configured as a mounting hole. In the example where the second driving mechanism is configured to include a rotating shaft, the rotating shaft can pass through the mounting hole and be connected to the powder spreading roller 2211 to enable the second driving mechanism to drive the rotation of the powder spreading roller 2211.

[0132] In one embodiment, as Figure 35 and Figure 36 shown, the doctor blade assembly 24 is configured to include a doctor blade 241. In order to distinguish it from Figure 37 and Figure 38 the doctor blade 241 included in the doctor blade assembly 24 shown, the Figure 35 and Figure 36 included doctor blade 241 can be referred to as the first doctor blade 241, and will not be elaborated further when the first doctor blade 241 is mentioned later. As Figure 35 and Figure 36 shown, the first doctor blade 241 is disposed on the central axis O1 of the powder spreading roller 2211 perpendicular to the forming platform 1, and is used to scrape the powder during the forward movement or return movement of the second base 221 in cooperation with the rotation of the powder spreading roller 2211.

[0133] In this example, the central axis O1 passes through the diameter of the cross-section where the powder spreading roller 2211 is located, and the first doctor blade 241 is vertically disposed at the highest position of the powder spreading roller 2211. As mentioned above, when the powder spreading device 22 performs forward powder spreading operation, that is, when the second base 221 is moving forward, the powder spreading roller 2211 rotates counterclockwise. At this time, the first doctor blade 241 can scrape the residual powder on the powder spreading roller 2211 and intercept the powder on the right side of the first doctor blade 241, and the scraped powder can continue to be used for forward powder spreading operation. When the powder spreading device 22 performs reverse powder spreading operation, that is, when the second base 221 is moving in reverse, the powder spreading roller 2211 rotates clockwise. At this time, the first doctor blade 241 can scrape the residual powder on the powder spreading roller 2211 and intercept the powder on the left side of the first doctor blade 241, and the scraped powder can continue to be used for reverse powder spreading operation.

[0134] Please refer to Figure 39 , which shows a schematic structural diagram of the first doctor blade in an embodiment of the present application. As Figure 39As shown, the first scraper 241 is wedge-shaped as a whole, and it can be configured to include an integrally formed main body portion 2411 and a blade portion 2412. In order to distinguish the main body portion and the blade portion included in the second scraper in the subsequent embodiments, the main body portion 2411 and the blade portion 2412 included in the first scraper 241 can be respectively referred to as the first main body portion 2411 and the first blade portion 2412. In this example, the installation of the first scraper 241 on the second base 221 can be realized by the first main body portion 2411, and the scraping of the residual powder on the powder spreading roller 2211 can be realized by the first blade portion 2412.

[0135] Please refer to Figure 40 and combine with Figure 36 , wherein, Figure 40 shows a schematic exploded view of the first scraper relative to the second base in an embodiment of the present application. As Figure 40 shown, the main frame 2212 defines an installation space 22123 for setting the first scraper 241 along the length direction of the powder spreading roller 2211. The installation space 22123 has a first opening 22124 facing the powder spreading roller 2211 so that the first blade portion 2412 of the first scraper 241 extends out of the first opening 22124 to contact the powder spreading roller 2211.

[0136] It should be understood that in an embodiment where the stiffness of the first scraper 241 is greater than that of the powder spreading roller 2211, for the powder particles adhered to the powder spreading roller and difficult to scrape off, if the first scraper 241 scrapes forcibly, it is easy to cause surface damage to the powder spreading roller 2211. In addition, the powder particles may be stuck between the first scraper 241 and the powder spreading roller 2211, thereby affecting the rotation of the powder spreading roller 2211 and making it difficult to smoothly carry out the powder spreading operation.

[0137] In view of this, please refer to Figure 41 , which shows a schematic view of the first scraper disposed in the installation space in an embodiment of the present application. As Figure 41 shown, the installation space 22123 has a redundant space 22125 for the first scraper 241 to move therein so that the first scraper 241 is separated from the powder spreading roller 2211 to allow foreign objects to pass through. The foreign objects can be, for example, strongly adhesive caked powder adhered to the powder spreading roller 2211. In this embodiment, the redundant space 22125 provides an avoidance space for the foreign objects to pass through. When the foreign objects rotate with the powder spreading roller 2211 and contact the first scraper 241, the redundant space 22125 allows the first scraper 241 to be pushed by the foreign objects and laterally displaced briefly to be separated from the powder spreading roller 2211, leaving a space for the foreign objects to pass through smoothly. This avoids scratching the surface of the powder spreading roller 2211 caused by the first scraper 241 scraping the foreign objects forcibly, and at the same time avoids the foreign objects being stuck between the first scraper 241 and the powder spreading roller 2211.

[0138] In one embodiment, the width of the channel forming the installation space 22123 is greater than the width of the first main body portion 2411 of the first squeegee 241 to form redundant spaces 22125 on the front and rear sides of the first main body portion 2411. For example, when the powder spreading roller 2211 rotates counterclockwise for forward powder spreading operation, the foreign object will contact the right side of the first squeegee 241 and push the first squeegee 241 against the left side of the channel, causing the first squeegee 241 to deflect to the left of the central axis O1 and separate from the powder spreading roller 2211 at the same time, so that the foreign object passes through the redundant space on the right side of the first main body portion 2411. When the powder spreading roller 2211 rotates clockwise for reverse powder spreading operation, the foreign object will contact the left side of the first squeegee 241 and push the first squeegee 241 against the right side of the channel, causing the first squeegee 241 to deflect to the right of the central axis O1 and separate from the powder spreading roller 2211 at the same time, so that the foreign object passes through the redundant space on the left side of the first main body portion 2411.

[0139] In one embodiment, the installation space 22123 is configured as a channel penetrating the upper and lower surfaces of the main frame 2212. The lower opening of the channel corresponds to the first opening 22124. The first squeegee 241 is placed in the channel and presses on the powder spreading roller 2211 by its own weight. In one example, the channel can be configured as a "T" - shaped structure, and the lower surface of the "T" - shaped structure corresponds to the first opening 22124. In this example, the first opening 22124 is formed on the lower side of the main frame 2212, and the first blade portion 2412 can protrude from the first opening 22124 and contact the powder spreading roller 2211 by its own weight. In another example, as Figure 40 shown, the channel is configured as a cuboid - shaped structure penetrating the upper and lower sides of the main frame 2212 and is provided at the center of the transverse plate 22121 of the main frame 2212. The first opening 22124 is an opening corresponding to the lower surface of the cuboid - shaped structure, so that the first blade portion 2412 can protrude from the opening and contact the powder spreading roller 2211 by its own weight. Of course, in some other examples, the channel can be configured as an "I" - shaped structure, etc. The present application does not impose any restrictions on this.

[0140] In this embodiment, the first opening 22124 can form the redundant spaces on the upper and lower sides of the first squeegee 241, so that the first squeegee 241 naturally adheres to the surface of the powder spreading roller 2211 only by its own gravity, and can avoid applying a forced pressure to the powder spreading roller 2211. For example, when there are large - particle powders difficult to remove attached to the powder spreading roller 2211, the first squeegee 241 can be pushed by the large - particle powders and temporarily lifted from the installation space 22123, thus avoiding surface damage of the powder spreading roller 2211 caused by rigid contact.

[0141] In another embodiment, the redundant space can be formed on the front and back sides, as well as the upper and lower sides of the first blade 241. That is, the first blade 241 can have free movement space in its four directions of up, down, left, and right. When the first blade 241 contacts a foreign object with strong adhesiveness, it can be briefly lifted or laterally shifted, and can quickly reset by its own weight after the foreign object passes through. At the same time, it makes it easy to install or disassemble the first blade 241 from the installation space 22123, thus facilitating the maintenance or replacement of the first blade 241. In addition, this flexible avoidance method can reduce the hard friction between the first blade 241 and the powder spreading roller 2211, avoid mechanical damage to the surface of the powder spreading roller 2211, and at the same time avoid the foreign object jamming the powder spreading roller 2211. It should be understood that even if the foreign object is difficult to scrape off due to strong adhesiveness and temporarily passes through the redundant space, it will contact the first blade 241 again and again as the powder spreading roller 2211 rotates, so as to gradually become loose until it is scraped off by the first blade 241.

[0142] Please refer to Figure 42 , which shows a schematic diagram of the contact between the first blade part and the powder spreading roller in an embodiment of the present application. As Figure 42 shown, a contact surface 24121 is formed at the end of the first blade part 2412 so that the first blade 241 scrapes the powder in a surface contact manner. It should be understood that scraping the powder in the form of surface contact can, on the one hand, increase the cleaning area of the first blade 241 for the powder spreading roller 2211 to ensure the cleaning effect, and on the other hand, can reduce the pressure exerted by the first blade 241 on the powder spreading roller 2211, thereby preventing mechanical damage to the powder spreading roller 2211. In some examples, the contact surface 24121 can be formed by a flat chamfer polished at the end of the first blade part 2412.

[0143] In an embodiment, as Figure 42 shown, the width w of the contact surface 24121 is set to 3 mm to 5 mm, for example, it can be approximately 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm, 3.9 mm, 4.0 mm, 4.1 mm, 4.2 mm, 4.3 mm, 4.4 mm, 4.5 mm, 4.6 mm, 4.7 mm, 4.8 mm, 4.9 mm, 5.0 mm, etc.

[0144] In another embodiment, as Figure 37 and Figure 38 shown, the scraper assembly 24 is configured to include two scrapers. In order to distinguish it from the first blade 241, Figure 37 and Figure 38The shown doctor blade assembly 24 includes two doctor blades, which are respectively referred to as the second doctor blade 242 and the third doctor blade 243, and will not be elaborated hereinafter when referring to the second doctor blade 242 and the third doctor blade 243. In this example, the second doctor blade 242 and the third doctor blade 243 are respectively located on the front and rear sides of the powder spreading roller 2211. Specifically, the second doctor blade 242 is located on the rear side of the powder spreading roller 2211 and is used to scrape the powder in cooperation with the forward rotation of the powder spreading roller 2211 during the return movement of the second base 221. The third doctor blade 243 is located on the front side of the powder spreading roller 2211 and is used to scrape the powder in cooperation with the reverse rotation of the powder spreading roller 2211 during the forward movement of the second base 221.

[0145] Specifically, when the powder spreading device 22 performs forward powder spreading operation, that is, when the second base 221 is moving forward, the powder spreading roller 2211 rotates counterclockwise. At this time, the third doctor blade 243 can scrape the residual powder on the powder spreading roller 2211 and intercept the powder on the front side of the powder spreading roller 2211, and the scraped powder can continue to be used for the forward powder spreading operation. When the powder spreading device 22 performs reverse powder spreading operation, that is, when the second base 221 is moving in the reverse direction, the powder spreading roller 2211 rotates clockwise. At this time, the second doctor blade 242 can scrape the residual powder on the powder spreading roller 2211 and intercept the powder on the rear side of the powder spreading roller 2211, and the scraped powder can continue to be used for the reverse powder spreading operation.

[0146] Please refer to Figure 43 , which shows a schematic structural diagram of the third doctor blade in an embodiment of the present application. As Figure 43 shown, the side of the third doctor blade 243 is integrally in an irregular pentagon shape. The third doctor blade 243 can be configured to include a main body part 2431 and a blade part 2432 that are integrally formed. In one embodiment, the second doctor blade 242 and the third doctor blade 243 can have the same configuration, that is, as Figure 38 shown, the second doctor blade 242 includes a main body part 2421 and a blade part 2422. In order to distinguish from the first main body part 2411 and the first blade part 2412 included in the first doctor blade 241, the main body part 2421 and the blade part 2422 included in the second doctor blade 242 can be referred to as the second main body part 2421 and the second blade part 2422, and the main body part 2431 and the blade part 2432 included in the third doctor blade 243 can be referred to as the third main body part 2431 and the third blade part 2432. In this example, the second doctor blade 242 and the third doctor blade 243 can be respectively installed on the second base 221 by the second main body part 2421 and the third main body part 2431, and the residual powder on the powder spreading roller 2211 can be respectively scraped by the second blade part 2422 and the third blade part 2432.

[0147] Please refer to Figure 44 and in combination with Figure 38 , wherein, Figure 44Shown is a schematic diagram of the second blade and the third blade disposed on the second base in an embodiment of the present application, as Figure 38 and Figure 44 shown. The second blade 242 and the third blade 243 are symmetrically disposed in a manner centered on the central axis O1 of the powder spreading roller 2211 perpendicular to the forming platform 1. In this example, the central axis O1 passes through the diameter of the cross-section where the powder spreading roller 2211 is located, and the second blade portion 2422 of the second blade 242 and the third blade portion 2432 of the third blade 243 symmetrically face and contact the surface of the powder spreading roller 2211 to scrape off the residual powder. In an example, as Figure 44 shown, the included angle α between the extension lines of the second blade portion 2422 and the third blade portion 2432 is 90° to 150°. For example, it can be approximately 90°, 95°, 100°, 105°, 110°, 115°, 120°, 125°, 130°, 135°, 140°, 145°, or 150°, etc. However, it is not limited thereto, and the angle of the included angle α can be adjusted otherwise according to actual production requirements.

[0148] In an embodiment, the second blade portion 2422 and the third blade portion 2432 scrape the powder by line contact. Wherein, the line contact means that when scraping the powder, the ends of the second blade portion 2422 and the third blade portion 2432 respectively adhere to the surface of the powder spreading roller 2211 in a straight line. In an example where the powder spreading roller 2211 is configured as a cylinder, the straight line at the joint between the second blade portion 2422 and the powder spreading roller 2211, or between the third blade portion 2432 and the powder spreading roller 2211, can be presented as coinciding with the generatrix of the cylinder. In this embodiment, scraping the powder in the form of line contact can increase the pressure exerted by the second blade 242 and the third blade 243 on the powder spreading roller 2211, making the powder easier to be scraped off.

[0149] The following takes the third blade portion 2432 in line contact with the powder spreading roller 2211 to scrape the powder as an example for description. Please refer to Figure 45 , shown is a schematic diagram of the third blade portion in line contact with the powder spreading roller in an embodiment of the present application, as Figure 45 shown. The third blade portion 2432 is in line contact with the powder spreading roller 2211, which can be specifically presented as a contact point 24321 is formed between the end of the pentagonal cross-section of the third blade 243 and the circular cross-section of the powder spreading roller 2211. Similarly, as Figure 44 shown, a contact point 24221 is formed between the second blade portion 2422 of the second blade 242 and the circular cross-section of the powder spreading roller 2211. For the convenience of description and distinction, the contact point 24221 between the second blade portion 2422 and the powder spreading roller 2211 is called the second contact point 24221, and the contact point 24321 between the third blade portion 2432 and the powder spreading roller 2211 is called the third contact point 24321.

[0150] In one embodiment, as Figure 44 shown, the angle β corresponding to the arc formed by the second contact point 24221 and the third contact point 24321 is 270° to 330°. For example, it can be approximately 270°, 275°, 280°, 285°, 290°, 295°, 300°, 305°, 310°, 315°, 320°, 325°, or 330°, etc.

[0151] In one embodiment, the second blade 242 and the third blade 243 are arranged on the side support plate 2213 in a way that the center of gravity is offset. Wherein, the center of gravity offset means that the center of gravity of the second blade 242 or the third blade 243 deviates from its geometric center, so that the overall weight of the second blade 242 or the third blade 243 is shifted towards the powder spreading roller 2211. In this embodiment, by the center of gravity offset method, the moments generated by the self-weights of the second blade 242 and the third blade 243 respectively make the second blade edge 2422 and the third blade edge 2432 automatically fit the surface of the powder spreading roller 2211, so that the pressure distribution on the surface of the powder spreading roller 2211 by the second blade edge 2422 and the third blade edge 2432 is uniform, and at the same time, the impact force of the foreign object on the second blade edge 2422 and the third blade edge 2432 can be reduced, and the probability of edge chipping can be lowered.

[0152] Taking the third blade 243 arranged on the side support plate 2213 as an example, please refer to Figure 46 and combine with Figure 37 and Figure 38 , wherein, Figure 46 shows the split structural schematic diagram of the third blade and the side support plate in one embodiment of the present application. As Figure 46 shown, on the basis of the side support plate 2213 being provided with a first installation part for installing the powder spreading roller 2211, a second installation part 22131 is further provided. The third blade 243 is installed on the second installation part 22131 and is inclined towards the powder spreading roller 2211 so that the third blade edge 2432 contacts the powder spreading roller 2211. In one example, the second installation part 22131 can be configured as a hole structure.

[0153] In one embodiment, as Figure 43 and Figure 46 shown, a rotatable shaft connecting member 2433 connected to the second installation part 22131 is arranged on the side end face of the third blade 243. The center of gravity of the third blade 243 is located in the area above the axis of the shaft connecting member 2433 so that the third blade 243 is inclined towards the powder spreading roller 2211 by gravity. In one implementation manner, the weight of the third main body part 2431 is greater than that of the third blade edge 2432. As Figure 43 shown, the shaft connecting member 2433 is configured on the third blade edge 2432.

[0154] It should be understood that when the center of gravity of the third scraper 243 is located in a region above the axis of the shaft connector 2433, the third scraper 243 tends to move along the axis due to its own weight. Figure 46 Rotate in the direction of the arrow shown in the middle arc. Figure 44 At the same time, the third scraper 243 stops rotating due to the obstruction of contact with the powder spreading roller 2211. In other words, the third scraper 243 is kept in the position due to its own gravity and the thrust exerted by the powder spreading roller 2211. Figure 44 The third blade 2432 faces and fits the powder roller 2211 to scrape off the powder. In the process of scraping off the powder, the third scraper 243 can also rotate around the shaft connector 2433 so that the third scraper 243 can be pushed by foreign objects and temporarily separated from the powder roller 2211, thereby establishing an avoidance mechanism for foreign objects to pass through, avoiding mechanical damage to the surface of the powder roller 2211 caused by forcibly scraping off foreign objects, and avoiding the foreign objects from being stuck between the third scraper 243 and the powder roller 2211. It should be understood that even if the foreign objects are difficult to scrape off due to their strong adhesion and temporarily pass through, they will contact the third scraper 243 again and again as the powder roller 2211 rotates, thereby gradually becoming loose until being scraped off.

[0155] Of course, in some other embodiments, the scraper assembly 24 can also be configured to include more than two scrapers. For example, the scraper assembly 24 can also be configured to include three scrapers, and the three scrapers can be configured as a first scraper 241, a second scraper 242, and a third scraper 243, respectively. The first scraper 241 is arranged on the powder spreading roller 2211 perpendicular to the central axis O1 of the molding platform 1, and the second scraper 242 and the third scraper 243 are symmetrically arranged along the central axis O1, but it is not limited to this, and can be determined according to actual production needs.

[0156] In one embodiment, if Figure 3 Shown and combined Figure 2 The powder spreading system 2 further includes a first material receiving component 21, which is arranged in the molding chamber and suspended in the first area 12. The powder spreading device 22 is arranged at the lower side of the first material receiving component 21. The suspension means that the upper end of the first material receiving component 21 is fixed to the molding chamber, and at this time, the lower end thereof is relatively free.

[0157] In one embodiment, the first powder receiving component 21 can be used to receive powder materials. In this embodiment, the powder spreading system 2 further includes a feeding component (not shown) for supplying the powder materials to the first powder receiving component 21. In one example, the feeding component can be configured to include a storage bin, a screw feeder, and a vibrating plate. The storage bin is used to store a certain amount of powder materials. The screw feeder can convey the powder materials from the storage bin to the first powder receiving component 21 in a spiral manner to achieve the supply of the powder materials. The vibrating plate can keep the powder materials in a loose state during the supply by vibrating, thereby preventing the powder materials from caking.

[0158] In one embodiment, the powder spreading system 2 further includes the aforementioned feeding component for adjusting the amount of the powder materials supplied to the first powder receiving component 21 according to the received instruction. In some examples, the amount of the powder materials refers to the weight or volume of the powder materials supplied to the first powder receiving component 21. In some examples, the feeding component can adjust the single powder supply amount or the powder supply times based on the printing requirements of each printing layer, such as parameters like layer thickness or printing speed, to achieve the adjustment of the amount of the powder materials supplied to the first powder receiving component 21.

[0159] In one example, the powder supply adjusting component can be configured to include a weighing sensor to monitor the actual powder supply mass supplied to the first powder receiving component 21, and generate a powder supply signal for transmission to the control device. The control device compares the actual powder supply mass with a target powder supply mass, thereby generating a control instruction to increase or decrease the powder supply amount, and outputting the control instruction to the feeding component. The feeding component can adjust the rotation speed of the screw feeder according to the control instruction, for example, to achieve the real-time adjustment of the powder supply amount. However, this is not a limitation, as long as the adjustment of the powder supply amount can be achieved.

[0160] As mentioned above, during the powder spreading process, when powder is fed, the height at which the powder falls will affect the forming quality. For example, in the related art, the powder directly falls from the first powder receiving component to the forming platform, and the powder falling height at this time can reach 120 mm, which will form dust in the forming chamber, thereby affecting the forming quality. In view of this, in one embodiment, as Figure 3 shown, the powder spreading device 22 further includes a second powder receiving component 222 for low-position powder falling. Specifically, the second powder receiving component 222 is used to dock with the first powder receiving component 21 to receive the powder materials from the first powder receiving component 21 and cache them when following the powder spreading roller 2211 towards the first area 12, and release the cached powder materials at a low position by the powder spreading roller 2211 when following the powder spreading roller 2211 towards the second area 13. The second powder receiving component provided in this embodiment that can perform low-position powder falling can reduce the powder falling height to less than 10 mm, thereby effectively avoiding dust.

[0161] In one embodiment, the powder dropping height of the powder spreading device 22 is greater than the stacking height of the powder material falling onto the forming platform 1. Wherein, the powder dropping height refers to the vertical distance that the powder material freely drops from the second material receiving component 222 to the forming platform 1, which is equal to the vertical distance from the second material receiving component 222 to the forming platform 1. It should be understood that if the powder dropping height is less than or equal to the stacking height, it may cause the powder outlet of the second material receiving component 222 to be blocked by the stacked powder material, thereby affecting the further dropping of the powder material in the second material receiving component 222, resulting in the interruption or uneven spreading of the powder spreading.

[0162] In one embodiment, the powder dropping height of the powder spreading device 22 is less than or equal to the height of the powder spreading roller 2211. Wherein, the height of the powder spreading roller 2211 refers to the height from the highest point of the powder spreading roller 2211 to the forming platform 1. In the example where the powder spreading roller 2211 is attached to the upper surface of the forming platform, the height of the powder spreading roller 2211 can correspond to the diameter height of the powder spreading roller 2211 perpendicular to the forming platform. It should be understood that if the powder dropping height is greater than the height of the powder spreading roller 2211, it will interfere with the effect of the powder spreading device 22 in avoiding dust emission. In practical applications, it is necessary to balance the powder dropping height, the stacking height of the powder material, and the height of the powder spreading roller, so as to ensure the continuity of powder dropping while effectively avoiding dust emission.

[0163] In one embodiment, as Figure 3 shown, the second material receiving component 222 is arranged on the second side of the second base 221. Please refer to Figure 23 , which shows the structural schematic diagram of the second material receiving component in one embodiment of the present application. As Figure 23 shown, the second material receiving component 222 includes a connecting member 223 and a second material receiving hopper 224. The connecting member 223 has a fixed section 2231 fixed on the second base 221 and a connecting section 2232 extending out of the second base 221 towards the second side. The second material receiving hopper 224 is arranged on the connecting section 2232 and hangs on the second side of the second base 221.

[0164] Wherein, the hanging means that the upper side of the second material receiving hopper 224 is fixed to the connecting section 2232, so that the lower side of the second material receiving hopper 224 can freely hang down. In one example, the connecting member 223 is configured as a connecting rod, and the fixed section 2231 on its first side is fixed to the second base 221 in a screwed manner, and the connecting section 2232 on the second side is connected to the second material receiving hopper 224. In one example, as Figure 23 shown, the connecting member 223 is configured as two, which are respectively connected to the opposite ends of the second material receiving hopper 224.

[0165] Please refer to Figure 24 and Figure 25 , which respectively show the structural schematic diagrams of the second material receiving hopper in different embodiments of the present application. As Figure 24 andFigure 25 As shown, the second material receiving hopper 224 includes a second hopper body 2241, a second material receiving port 2242, and a second material discharging port 2243. The second hopper body 2241 is used for caching powder materials, the second material receiving port 2242 is used for docking with the first material receiving assembly 21, and the second material discharging port 2243 is used for releasing the cached powder materials at a low position onto the moving path of the powder spreading roller 2211. In Figure 24 and Figure 25 the illustrated example, the powder materials can be supplied by the feeding assembly to the first material receiving assembly 21, fall into the second hopper body 2241 through the second material receiving port 2242, and finally fall onto the forming platform 1 through the second material receiving port 2242.

[0166] In one embodiment, as shown in Figure 24 and Figure 25 the second hopper body 2241 includes a caching portion 22412 and a guiding portion 22413. The caching portion 22412 is in communication with the second material receiving port 2242. The guiding portion 22413 is formed following the caching portion 22412 and is in communication with the second material discharging port 2243. The guiding portion 22413 is inclined towards the powder spreading roller 2211 to guide the falling powder. In one example, as shown in Figure 24 and Figure 25 the caching portion 22412 is the vertical portion of the second hopper body 2241, and the guiding portion 22413 is the inclined portion of the second hopper body 2241. The connection between the caching portion 22412 and the guiding portion 22413 forms a corner on the second hopper body 2241, and this corner can provide a buffering effect for the falling of the powder cached in the caching portion 22412. In this example, the feeding assembly supplies the powder materials to the first material receiving assembly 21, which enters the caching portion 22412 of the second hopper body 2241 through the second material receiving port 2242. The powder cached in the caching portion 22412 flows towards the inclined guiding portion 22413 due to gravity and falls through the second material discharging port 2243. In one example, the inner wall of the second hopper body 2241 can be made smooth to reduce the adhesion of powder materials.

[0167] In one embodiment, as shown in Figure 25 the second material receiving hopper 224 further includes a door assembly 2246. The door assembly 2246 is arranged on the second hopper body 2241 to open or close the second material discharging port 2243. Please refer to Figure 26 and in combination with Figure 25 , wherein, Figure 26Shown is a schematic diagram of the state of the second material receiving hopper during reverse powder spreading operation in an embodiment of the present application. Among them, the second material receiving hopper 224 includes a door assembly 2246. When the powder spreading device 22 performs reverse powder spreading operation, that is, when the second material receiving hopper 224 moves towards the first area 12 and docks with the first material receiving component 21, the door assembly 2246 is in the closed state as shown in 25. At this time, powder can be cached in the second material receiving hopper 224. When the powder spreading device 22 is about to perform forward powder spreading operation, that is, when the second material receiving hopper 224 moves towards the second area 13, the door assembly 2246 is in the open state as shown in Figure 26 . At this time, the powder can fall onto the powder spreading roller 2211 through the guiding portion 22413, thereby further reducing the powder falling height to enhance the effect of avoiding dust generation.

[0168] Please refer to Figure 27 and combine with Figure 25 . Among them, Figure 27 Shown is a schematic diagram of the structure of the door assembly in an embodiment of the present application. As shown in Figure 25 and Figure 27 , the door assembly 2246 includes a mounting assembly 2247 and a door body 2248. The mounting assembly 2247 is arranged on the upper side of the second material falling opening 2243. One side of the door body 2248 is rotatably connected to the mounting assembly 2247 and forms an included angle with the second material falling opening 2243 on the other side. Among them, the included angle refers to the opening degree of the door body 2248 relative to the second material falling opening 2243. For example, when the door body 2248 is switched from the closed state shown in Figure 25 to the open state shown in Figure 26 , the included angle gradually increases.

[0169] In an embodiment, the mounting assembly 2247 can be configured as a hinge. One end of it can be connected to the second hopper body 2241 on the upper side of the second material falling opening 2243 through bolts, for example, and the other end can be connected to the upper side of the door body 2248, so that the door body 2248 can rotate around the hinge as the axis to realize the opening and closing of the second material falling opening 2243.

[0170] In an embodiment, as shown in Figure 27 , the door body 2248 includes a body portion 22481 and a closed portion 22482 bent on both sides of the body portion 22481. Figure 25As shown, the closing portion 22482 can be attached to both sides of the second hopper body 2241 so that the door assembly 2246 can completely close the second discharge opening 2243 when closed, thereby preventing powder from leaking from the joint between the door body 2248 and the second hopper body 2241. In some examples, a buffer member may be disposed at the closing portion 22482 to prevent impact between the door body 2248 and the second hopper body 2241 when the door assembly 2246 is closed. The buffer member may be configured as, for example, a rubber strip or a silica gel pad, etc.

[0171] In one embodiment, as Figure 23 shown, the second receiving hopper 224 is rotatably disposed on the connecting section 2232. In some examples, the second receiving hopper 224 can be rotated by an angle of 10° to 45°, for example, approximately 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, 45°, 46°, 47°, 48°, 49°, 50°, 51°, 52°, 53°, 54°, 55°, 56°, 57°, 58°, 59°, 60°, etc. It should be noted that the rotation angle refers to the rotation angle of the second receiving hopper 224 around a certain rotation axis, which can be presented by the included angle between the plane where the second receiving opening 2242 is located and the planes where the two connecting sections 2232 are located. Among them, the rotation axis can be the shaft assembly 22411 described in subsequent embodiments.

[0172] In one embodiment, as Figure 24 and Figure 25 shown, a shaft assembly 22411 mounted on the connecting section 2232 is provided on the second hopper body 2241. The shaft assembly 22411 is supported on the connecting section 2232 so that the second receiving opening 2242 of the second receiving hopper 224 hangs in an inclined posture with the second side higher than the first side. The hanging state of the second receiving hopper 224 is as shown in Figure 26 illustrated. Among them, the inclined posture hanging means the natural state of the second receiving hopper 224 when not affected by external forces, for example, the state when the second receiving hopper 224 does not come into contact with the first receiving assembly 21.

[0173] In one embodiment, the height position of the first side of the second receiving opening 2242 is lower than that of the first receiving assembly 21 to allow the second receiving hopper 224 to pass through the first receiving assembly 21. Specifically, please refer to Figures 28 to 30 and combine with Figure 26 , where Figures 28 to 30Schematically shown is the process of the second material receiving hopper passing through the first material receiving assembly and docking with the first material receiving assembly in an embodiment of the present application. As described above, the first material receiving assembly 21 is suspended in the first area 12, and the upper side of the second material receiving hopper 224 is fixed to the connecting section 2232. As Figure 26 shown, when the second material receiving hopper 224 moves towards the first area 12 following the powder spreading roller 2211, the second material receiving hopper 224 moves relatively away from the first material receiving assembly 21, and the second material receiving hopper 224 is in a hanging state.

[0174] Thereafter, as Figure 28 shown, the second material receiving hopper 224 moves towards the first material receiving assembly 21 driven by the powder spreading device 22 and gradually approaches the first material receiving assembly 21 until the second side of the second material receiving hopper 224 contacts the second side of the first material receiving assembly 21. As Figure 29 shown, the second material receiving hopper 224 continues to move towards the first area 12. During this process, the second material receiving hopper 224 will rotate clockwise under the resistance of the first material receiving assembly 21, thereby causing the second material receiving hopper 224 to gradually rotate from the hanging state to Figure 29 the docking state shown. In the docking state shown in Figure 30 , the second material receiving assembly 222 can receive the powder from the first material receiving assembly 21 and cache it.

[0175] It should be noted that Figures 28 to 30 only schematically illustrates the docking process of the second material receiving hopper 224 and the first material receiving assembly 21 when the powder spreading device 22 performs reverse powder spreading operation. It should be understood that during the forward powder spreading operation of the powder spreading device 22, the second material receiving hopper 224 gradually moves away from the first material receiving assembly 21 from the docking state shown in Figure 30 and presents the hanging state shown in Figure 26 .

[0176] In an embodiment, please refer to Figure 31 and combine with Figure 23 . Figure 31 Shown is a schematic diagram of the connecting member in an embodiment of the present application. As Figure 23 and Figure 31As shown, a groove 22321 for accommodating the shaft assembly 22411 is provided on the connecting section 2232 of the connecting member 223, and the groove 22321 has an opening to enable the shaft assembly 22411 to enter or leave the groove 22321. Among them, the shaft assembly 22411, as the rotating shaft of the second material receiving hopper 224, can drive the second material receiving hopper 224 to rotate within the groove 22321. In one example, the groove 22321 is generally in a "U" shape, and its opening corresponds to the opening of the "U" shape, so that the shaft assembly 22411 can enter or leave the groove 22321 from the opening of the "U" shape, facilitating the cleaning or replacement of the second material receiving hopper 224.

[0177] In one embodiment, as Figure 24 and Figure 25 shown, the second material receiving hopper 224 further includes a blocking portion 2244 protruding from the second side of the second material receiving opening 2242. When the second material receiving hopper 224 moves toward the first area 12 through the first material receiving assembly 21, the blocking portion 2244 is blocked by the first material receiving assembly 21 to cause the second material receiving hopper 224 to rotate toward the first material receiving assembly 21 for docking with the first material receiving assembly 21. In one example, the blocking portion 2244 is configured as a plate-like structure extending from the side wall of the second side of the second hopper body 2241, and it can abut against the second side of the first material receiving assembly 21 to block the first material receiving assembly 21. In some implementation manners, it can be integrally formed with the side wall of the second hopper body 2241 or fixed to the side wall of the second hopper body 2241 by welding or other means.

[0178] Please refer to Figures 28 to 30 , during the process of the second material receiving hopper 224 following the powder spreading roller 2211 and moving toward the first area 12, the blocking portion 2244 gradually abuts against the second side of the first material receiving assembly 21, and when they just come into contact, it can present the state shown in Figure 28 . Then, due to the movement of the second material receiving hopper 224 toward the first area, a thrust is exerted on the second side of the first material receiving assembly 21 by the blocking portion 2244. This thrust causes the second material receiving hopper 224 to rotate clockwise within the groove 22321 with the shaft assembly 22411 as the axis, so that the angle between the bottom of the first material receiving assembly 21 and the top of the second material receiving hopper 224 gradually decreases, and then presents the state shown in Figure 29 . As shown in Figure 30 , when the blocking portion 2244 fits against the second side of the first material receiving assembly 21, the second material receiving hopper 224 and the first material receiving assembly 21 can complete the docking.

[0179] In one embodiment, as Figure 24 and Figure 25 shown, the second material receiving hopper 224 further includes a second stopping portion 2245 located on the first side of the second material receiving opening 2242. As shown in Figures 28 to 30As shown, a first stopping portion 2133 corresponding to the second stopping portion 2245 is provided on the first material receiving assembly 21. When the second material receiving hopper 224 is docked with the first material receiving assembly 21, the first stopping portion 2133 cooperates with the first stopping portion 2133 to prevent the second material receiving hopper 224 from over-rotating. It should be noted that the first stopping portion 2133 can be further provided on the docking portion 213 of the first material receiving assembly 21. The specific structure of the docking portion 213 will be described in detail later.

[0180] It should be understood that the over-rotation refers to the continuous rotation of the second material receiving hopper 224 after the first material receiving assembly 21 is docked with the second material receiving hopper 224. This continuous rotation will cause the first material receiving assembly 21 and the second material receiving hopper 224 to deviate from the docking state. For example, if the first stopping portion and the second stopping portion are not provided, when the first material receiving assembly 21 is completely docked with the second material receiving hopper 224 and presents Figure 30 the state shown, the second material receiving hopper 224 will still have a tendency to move towards the first area 12 under the drive of the powder spreading roller 2211. Under this tendency, the second material receiving hopper 224 will continuously rotate clockwise in the groove 22321 with the shaft assembly 22411 as the axis.

[0181] In one embodiment, both the first stopping portion 2133 and the second stopping portion 2245 are configured as plate-like structures extending horizontally from the corresponding material receiving assemblies. When the first material receiving assembly 21 and the second material receiving hopper 224 are in Figure 30 the docking state shown, the first stopping portion 2133 and the second stopping portion 2245 are attached to each other to serve as a limiting device to prevent the second material receiving hopper 224 from continuously rotating clockwise.

[0182] In, for example, Figures 28 to 30 the embodiment where the second material receiving hopper 224 is rotatable and includes the door body 2248, when the second material receiving hopper 224 rotates to dock with the first material receiving assembly 21, the door body 2248 gradually closes the included angle by its own weight to receive materials, and forms the included angle again through the rotational movement when the second material receiving hopper 224 moves away from the first material receiving assembly 21 towards the second area 13 to discharge materials. That is to say, the opening or closing of the door body 2248 relative to the second material discharging port 2243 is driven by the self-weight of the door body 2248. As Figure 26 shown, the second material receiving hopper 224 hangs vertically due to its center of gravity in the natural state. At this time, the door body 2248 naturally hangs down due to its own gravity, so that it is in the open state.

[0183] It should be understood that as the second receiving hopper 224 rotates clockwise, the door body 2248 will first maintain its natural hanging state due to inertia, and then cover the second material dropping opening 2243 following the rotation of the second receiving hopper 224 to achieve its closed state. Of course, in some other embodiments, the door body 2248 can also be connected to a driving mechanism, and the opening angle of the door body 2248 can be automatically adjusted through the driving mechanism.

[0184] In one embodiment, a counterweight portion is provided at one end of the door body 2248 close to the forming area 11. The counterweight portion can lower the center of gravity of the door body 2248 to make the rotation of the door body 2248 around the mounting assembly 2247 more stable. In some examples, the counterweight portion can be configured as a metal block.

[0185] The following will combine Figure 26 and Figures 28 to 30 to describe the opening or closing process of the door body 2248 in detail: When the powder spreading device 22 completes the reverse powder spreading operation, that is, when the second receiving hopper 224 moves towards the first area 12, the second receiving hopper 224 gradually changes from the Figure 26 hanging state shown to the Figure 30 docking state shown. During this process, the opening angle of the door body 2248 gradually decreases until the second material dropping opening 2243 is closed to present the closed state of the door assembly 2246. At this time, the powder can enter the second receiving hopper 224 from the first receiving component 21 and be cached in the second hopper body 2241. When the powder spreading device 22 is about to perform the forward powder spreading operation, that is, when the second receiving hopper 224 moves towards the second area 13, the second receiving hopper 224 gradually changes from the Figure 30 docking state shown to the Figure 26 hanging state shown. During this process, the opening angle of the door body 2248 gradually increases until the second material dropping opening 2243 is opened to present the open state of the door assembly 2246. At this time, the powder cached in the second hopper body 2241 can drop powder towards the lower position of the powder spreading roller 2211, so as to facilitate the powder spreading roller 2211 to perform powder spreading in the forming area 11.

[0186] Please refer to Figure 32 and Figure 33 , where Figure 32 shows a schematic diagram of the first receiving component in one embodiment of the present application, Figure 33 shows a cross-sectional schematic diagram of the second receiving hopper docking with the first receiving component in one embodiment of the present application. As shown in Figure 32 and Figure 33As shown, the first material receiving component 21 includes a first material receiving hopper 211, and the first material receiving hopper 211 includes a first hopper body 212 and a docking portion 213. Further, the first hopper body 212 has a first material receiving port 2121 and a first material discharging port 2122. In this example, the first material receiving port 2121 and the first material discharging port 2122 are respectively located on the upper side and the lower side of the first hopper body 212. The first material receiving port 2121 is used to communicate with the aforementioned feeding component to supply the powder material to the first material receiving component 21. When the second material receiving component 222 is docked with the first material receiving component 21, the first material discharging port 2122 is communicated with the second material receiving port 2242 to facilitate the powder material to fall from the second material discharging port 2243. In one example, the first hopper body 212 and the docking portion 213 can be connected in an integrally formed manner or a fixed connection manner. In one example, the inner wall of the first hopper body 212 can be made smooth to reduce the adhesion of the powder material. In one example, the width of the first hopper body 212 can be smaller than the width of the second hopper body 2241 so that the powder material in the first material receiving component 21 can smoothly enter the second material receiving component 222.

[0187] As Figure 32 and [[ID=280 shown, the docking portion 213 extends downward corresponding to the first material discharging port 2122, and enters the second material receiving port 2242 when the second material receiving hopper 224 is docked with the first material receiving component 21 to guide the powder material into the second material receiving component 222. It should be understood that when the second material receiving hopper 224 is docked with the first material receiving component 21, the docking portion 213 can extend into the second material receiving port 2242 to prevent the powder material from leaking from the joint between the first material receiving component 21 and the second material receiving component 222.

[0188] It should be understood that if there is powder material attached to the hopper wall of the first material receiving hopper or the second material receiving hopper, these powder materials may accumulate in the first material receiving hopper or the second material receiving hopper due to caking or electrostatic adsorption, thereby affecting the supply of the powder material. More importantly, these powder materials may fall onto the powder layer that has completed the powder spreading operation, thus affecting the printing operation. For example, when the powder spreading device 22 drives the second material receiving hopper 224 to perform a reverse powder spreading operation and passes through the forming area 11, the area on the right side of the second material receiving hopper 224 has completed the powder spreading operation. At this time, if the powder material in the second material receiving hopper 224 falls onto the forming area 11 again, the current powder spreading operation will be in vain. In view of this, a second baffle or a first baffle is provided on the docking portion 213 of the first material receiving hopper 211 disclosed in this application to shake off the powder materials remaining on the hopper wall of the first material receiving hopper 211 or the second material receiving hopper 224 respectively.

[0189] Please refer to ​ , which shows a partial enlarged schematic view of the A position in the embodiment shown in this application ​ As ​As shown, the docking portion 213 includes a second baffle 2132 located on the second side of the first blanking port 2122. The second baffle 2132 is used to block the blocking portion 2244. Moreover, when the blocking portion 2244 rotates with the second material receiving hopper 224, it is impacted by the second baffle 2132 to shake off the powder residue on the inner wall of the first material receiving hopper 211.

[0190] Specifically, during the reverse powder spreading operation, the first material receiving assembly 21 may first be located at, for example, the initial position. The second material receiving hopper 224 is driven by the powder spreading device 22 to complete a forward powder spreading operation with the powder spreading roller 2211 and is located at the return position. At this time, the second material receiving hopper 224 is in ​ the hanging state as shown. As the powder spreading device 22 drives the second material receiving hopper 224 to move towards the initial position for the reverse powder spreading operation, the first material receiving assembly 21 and the second material receiving hopper 224 gradually complete ​ the docking process as shown.

[0191] When the two are docked, the blocking portion 2244 and the second baffle 2132 are in mutual contact. As previously described, the second material receiving hopper 224 still has a tendency to move towards the first area 12 under the drive of the powder spreading roller 2211. Under this tendency, on the one hand, the blocking portion 2244 blocks the continuous translation of the second material receiving hopper 224 and causes it to rotate around the shaft assembly 22411 as the axis. On the other hand, the blocking portion 2244 will impact the second baffle 2132, thereby shaking off the powder residue on the inner wall of the first material receiving hopper 211. This enables the first material receiving assembly 21 to ensure the complete drop of the powder during each powder spreading operation, preventing both the first material receiving assembly 21 from being blocked by the residual powder and powder waste.

[0192] In one embodiment, as ​ shown, the docking portion 213 includes a first baffle 2131 located on the first side of the first blanking port 2122. The first baffle 2131 is used to impact the second material receiving hopper 224 that rotates by its own weight when the second material receiving hopper 224 moves towards the second area 13 to shake off the powder residue on the inner wall of the second material receiving hopper 224.

[0193] Specifically, when the second material receiving hopper 224 moves towards the second area 13 for the forward powder spreading operation, the second material receiving hopper 224 changes from ​ the docking state as shown to ​ the hanging state as shown. At this time, the first baffle 2131 will impact the inner wall of the first side of the second material receiving hopper 224, thereby shaking off the powder residue on the inner wall of the second material receiving hopper 224. In one example, the first baffle 2131 or the second baffle 2132 may be configured with an impact-resistant material such as hardened steel.

[0194] In summary, for the 3D printing device and powder spreading system disclosed in this application, the powder spreading operation is realized by a powder spreading device that can move back and forth between the first area and the second area of the forming platform. By arranging a first material receiving component suspended in the first area and a second material receiving component that can move with the powder spreading roller in the forming chamber, when the powder spreading roller moves towards the first area, the docking of the first material receiving component and the second material receiving component can be realized, so that the powder is cached in the second material receiving component. In addition, when the powder spreading roller moves towards the second area, the first material receiving component and the second material receiving component can be separated from each other, so that the second material receiving component releases the powder at a low position, thus avoiding dusting and ensuring the forming environment in the forming chamber. By arranging a door component that can open or close the second material dropping port at the second material receiving hopper of the second material receiving component, the powder can be cached in the second material receiving hopper and then dropped, thereby further reducing the powder dropping height. By arranging a second baffle or a first baffle on the docking part of the first material receiving hopper, the powder remaining on the hopper wall of the first material receiving hopper or the second material receiving hopper can be shaken off respectively, so as to prevent the powder from accumulating in the material receiving hopper and prevent the powder from falling onto the powder layer that has completed the powder spreading operation, ensuring the powder spreading effect.

[0195] Furthermore, by arranging a powder spreading roller in the powder spreading device that can be driven to rotate when following the base to move horizontally, the powder can be laid in the forming area. By arranging a scraper in the powder spreading device that contacts the powder spreading roller along the length direction of the powder spreading roller, the scraper can be integrally attached to the surface of the powder spreading roller, thereby preventing the powder from remaining. In addition, the design of the scraper can also prevent the powder with a certain hardness from being embedded therein, thus avoiding scratches on the powder spreading roller.

[0196] When the scraper assembly is configured to include one scraper, by configuring the scraper to press on the powder spreading roller by its own weight and arranging a redundant space for the scraper to move in the installation space, when the scraper contacts a foreign object with strong adhesiveness, the scraper can be briefly lifted or shifted laterally, and can quickly reset by its own weight after the foreign object passes, which is also beneficial to the disassembly and assembly of the scraper. In addition, this flexible avoidance method reduces the hard friction between the scraper and the powder spreading roller, avoids mechanical damage to the surface of the powder spreading roller, and avoids the foreign object jamming the powder spreading roller.

[0197] When the scraper assembly is configured to include two scrapers, by arranging the two scrapers on the base in a way that the center of gravity is offset, the moment generated by the self-weight of the two scrapers makes the blade parts automatically fit the surface of the powder spreading roller respectively, so that the pressure distribution on the surface of the powder spreading roller by the blade parts is uniform, and at the same time, it can slow down the impact force of foreign objects on the blade parts, reducing the probability of edge chipping.

[0198] In addition, by providing a powder spreading device in the powder spreading system that can move back and forth between the first area and the second area of the forming platform, the powder spreading operations in the leveling stage and the printing stage can be achieved. By providing a powder return detection mechanism above the first powder return tank, the detection of the powder surface distance of the first powder return tank can be achieved when the powder spreading device completes one round trip movement, so that the detection of whether the leveling stage is completed can be achieved, ensuring that the powder layer in the forming area has been leveled before the printing stage. Alternatively, the powder return detection mechanism can determine the powder supply amount for the next powder spreading operation, thereby preventing excessive or insufficient powder supply, avoiding waste of powder, and ensuring the smooth progress of the printing operation. By providing a cooling mechanism in the powder return detection mechanism, the normal operation of the powder return detection mechanism can be prevented from being affected by the high temperature environment in the forming chamber. By providing a light-transmitting protection plate in the optical channel of the powder return detection mechanism, a physical barrier can be provided to prevent powder from affecting the powder return detection mechanism from receiving the reflected light signal. By providing a gas guiding structure that can direct the airflow from the cleaning mechanism to the lower side of the light-transmitting protection plate to clean the powder or oil mist on the light-transmitting protection plate, the powder or oil mist on the light-transmitting protection plate can be cleaned, thereby further ensuring the normal operation of the powder return detection mechanism.

[0199] The above embodiments merely illustrate the essence of the invention of the present application and the beneficial effects obtained thereby, and are not intended to limit the present application. Any person familiar with this technology can modify or change the above embodiments without departing from the principles and scope of the present application. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present application should still be covered by the claims of the present application.

Claims

1. A powder spreading system for a 3D printing device, characterized in that, The 3D printing device includes a forming platform and a forming chamber located on the forming platform. The forming platform has a forming area, and a first area and a second area located on opposite sides of the forming area. The powder spreading system includes: A first material receiving component, which is arranged in the forming chamber and suspended in the first area. The first material receiving component includes a first material receiving hopper, the first material receiving hopper has a first material discharging opening and a docking portion extending downward corresponding to the first material discharging opening. The docking portion includes a first baffle located on a first side of the first material discharging opening; A powder spreading device, which is arranged under the first material receiving component and is used to perform forward powder spreading operation on the forming platform when driven to move from the first area towards the second area and perform reverse powder spreading operation on the forming platform when moving from the second area back to the first area. The powder spreading device includes a powder spreading roller for spreading powder on the forming area and a second material receiving component for low-position powder dropping. Wherein, the second material receiving component is used to dock with the first material receiving component to receive powder from the first material receiving component and cache it when following the powder spreading roller towards the first area, and release the cached powder at a low position when following the powder spreading roller towards the second area; Wherein, the second material receiving component includes a connecting piece and a second material receiving hopper. The connecting piece has a fixed section fixed on a base and a connecting section extending out of the base towards a second side. The second material receiving hopper is rotatably arranged on the connecting section and hangs vertically on the second side of the base. The second material receiving hopper includes a second hopper body for caching powder, a second material receiving opening for docking with the first material discharging opening of the first material receiving component, a blocking portion protruding on a second side of the second material receiving opening, and a second material discharging opening for dropping the cached powder to the moving path of the powder spreading roller at a low position. The blocking portion is blocked by the first material receiving component when the second material receiving hopper moves towards the first area past the first material receiving component, so as to cause the second material receiving hopper to rotate towards the first material receiving component to dock with the first material receiving component. When the second material receiving hopper moves towards the second area and rotates by its own weight to drop powder at a low position, it impacts the first baffle to shake off the powder remaining on the inner wall of the second material receiving hopper.

2. The powder spreading system of the 3D printing device according to claim 1, characterized in that The powder dropping height of the powder spreading device is greater than the stacking height of the powder falling onto the forming platform.

3. The powder spreading system of the 3D printing device according to claim 1, characterized in that The powder dropping height of the powder spreading device is less than or equal to the height of the powder spreading roller.

4. The powder spreading system of the 3D printing device according to claim 1, characterized in that, The powder spreading device includes a base arranged in the forming chamber and connected to a powder spreading driving mechanism. The powder spreading roller is arranged on the base and located on a first side, and the second material receiving component is arranged on a second side of the base.

5. The powder spreading system of the 3D printing device according to claim 1, wherein The rotatable angle of the second material receiving hopper is 10° to 60°.

6. The powder spreading system of the 3D printing device according to claim 1, wherein An axial component is arranged on the second hopper body and installed on the connection section. The axial component is supported on the connection section so that the second material receiving port of the second material receiving hopper is suspended in an inclined posture with the second side higher than the first side. Among them, the height position of the first side of the second material receiving port is lower than that of the first material receiving component to allow the second material receiving hopper to pass through the first material receiving component.

7. The powder spreading system of the 3D printing device according to claim 6, characterized in that A groove for accommodating the axial component is arranged on the connection section, and the groove has an opening so that the axial component can enter or leave the groove.

8. The powder spreading system of the 3D printing device according to claim 1 or 6, characterized in that, The first material receiving component includes a first material receiving hopper, and the first material receiving hopper includes: A first hopper body having a first material receiving port and a first material discharging port; A docking part extending downward corresponding to the first material discharging port, which enters the second material receiving port when the second material receiving hopper docks with the first material receiving component to guide the powder into the second material receiving component.

9. The powder spreading system of the 3D printing device according to claim 8, characterized in that, The docking part includes a second baffle located on the second side of the first material discharging port. The second baffle is used to block the blocking part and is impacted by the second baffle when the second material receiving hopper rotates to shake off the powder remaining on the hopper wall of the first material receiving hopper.

10. The powder spreading system of the 3D printing device according to claim 8, characterized in that, The second material receiving hopper further includes a second stopping part located on the first side of the second material receiving port. The docking part is provided with a first stopping part corresponding to the second stopping part. The first stopping part cooperates with the first stopping part when the second material receiving hopper docks with the first material receiving component to prevent the second material receiving hopper from over-rotating.

11. The powder spreading system of the 3D printing device according to claim 1, characterized in that, The second hopper body includes a buffer part communicated with the second material receiving port and a guiding part formed in compliance with the buffer part and communicating with the second material discharging port. The guiding part inclines towards the powder spreading roller to guide the falling powder.

12. The powder spreading system of the 3D printing device according to claim 1, wherein The second material receiving hopper further includes a door assembly arranged on the second hopper body to open or close the second material discharging port.

13. The powder spreading system of the 3D printing device according to claim 12, characterized in that, The door assembly includes: An installation assembly arranged on the upper side of the second material discharging port; A door body, one side of which is rotatably connected to the installation assembly and forms an included angle with the second material discharging port on the other side. When the second material receiving hopper rotates to dock with the first material receiving component, it gradually closes the included angle by its own weight to receive materials, and forms the included angle again through the rotational movement when the second material receiving hopper leaves the first material receiving component and moves towards the second area to discharge materials.

14. The powder spreading system of the 3D printing device according to claim 13, characterized in that, The door body includes a body part and closing parts bent on both sides of the body part.

15. The powder spreading system of the 3D printing device according to claim 13, characterized in that, A counterweight part is arranged at one end of the door body close to the forming area.

16. The powder spreading system of the 3D printing device according to claim 1, characterized in that, The powder spreading system further includes a feeding component for supplying powder to the first material receiving component.

17. The powder spreading system of the 3D printing device according to claim 1, characterized in that The powder spreading system further includes an adjusting feeding component for adjusting the amount of powder supplied to the first material receiving component according to the received instruction.

18. A 3D printing device, characterized in that, Including: A forming platform having a forming area and a first area and a second area located on opposite sides of the forming area. A component mechanism is arranged corresponding to the forming area. The component mechanism is used to move layer by layer in the vertical direction to attach 3D components formed layer by layer by irradiating the forming area through an optical system. The powder spreading system according to any one of claims 1 to 17, for spreading powder in the forming area; An optical system for emitting a light beam to irradiate powder in the shaping area; A control device, connected to the optical system, the component mechanism, and the powder spreading system, for controlling the powder spreading system to spread powder into the shaping area under a printing operation, controlling the optical system to irradiate the powder in the shaping area, and controlling the component mechanism to move vertically under a printing operation to attach the 3D component formed layer by layer to the component mechanism.

19. The 3D printing device according to claim 18, wherein, The 3D printing device is a selective laser sintering 3D printer.

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