3D printing equipment and powder spreading system thereof

Abstract

The 3D printing equipment comprises a forming platform and a forming chamber located on the forming platform, and the forming platform is provided with a forming area, a first area and a second area, and the first area and the second area are located on the two opposite sides of the forming area. The powder laying system comprises a first material receiving assembly arranged in the forming chamber and suspended in the first area and a powder laying device arranged on the lower side of the first material receiving assembly and used for conducting powder laying operation, and the powder laying device comprises a powder laying roller used for laying powder in the forming area and a second material receiving assembly used for low-position powder falling. And the second material receiving assembly is used for being in butt joint with the first material receiving assembly to receive and cache the powder when moving towards the first area along with the powder spreading roller, and releasing the powder at a low position by the powder spreading roller when moving towards the second area along with the powder spreading roller. Through butt joint and separation of the first material receiving assembly and the second material receiving assembly at the specific position, low-position release of powder is achieved, so that dust raising is avoided, and the forming environment in the forming chamber is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of 3D printing, and in particular to a 3D printing device and a powder spreading system thereof. Background Art

[0002] 3D printing technology is a type of rapid prototyping technology. It is a technology that uses digital model files as the basis, uses powdered metals, plastics, resins and other bondable materials, and constructs objects by printing layer by layer. With the rapid development of industrial technology, various 3D printing technologies using powder materials as raw materials are constantly emerging, such as 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 SLS 3D printing equipment as an example, when printing, it is necessary to use a powder laying system to lay powder layer by layer in the molding area. During the powder laying process, when the powder is dropped, the height of the powder falling will affect the molding quality. For example, in the related technology, the powder is directly dropped from the powder supply mechanism to the molding platform, which will form dust and affect the molding environment. Therefore, how to achieve low-level powder dropping during the powder laying operation is a technical problem that technicians in this field need to solve urgently. Summary of the invention

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

[0005] To achieve the above-mentioned purpose and other related purposes, the first aspect of the present application provides a powder spreading system for a 3D printing device, the 3D printing device comprising a molding platform and a molding chamber located on the molding platform, the molding platform having a molding area and a first area and a second area located on opposite sides of the molding area, the powder spreading system comprising: a first material receiving component, arranged in the molding chamber and suspended in the first area; a powder spreading device, arranged on the lower side of the first material receiving component, for being driven to move back and forth between the first area and the second area to perform powder spreading operations on the molding platform, the powder spreading device comprising a powder spreading roller for spreading powder on the molding 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 when following the powder spreading roller moving toward the first area to receive and cache the powder from the first material receiving component, and to release the cached powder at a low position by the powder spreading roller when following the powder spreading roller moving toward the second area.

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

[0007] In summary, the 3D printing device and powder spreading system thereof provided by the present application realize powder spreading operation through a powder spreading device that can move back and forth between the first area and the second area of ​​the molding 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 molding chamber, the first material receiving component and the second material receiving component can be docked when the powder spreading roller moves toward the first area, so that the powder material is buffered in the second material receiving component. In addition, when the powder spreading roller moves toward 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 material at a low position, thereby avoiding dust and ensuring the molding environment in the molding chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The specific features of the present application are shown in the attached claims. The features and advantages of the invention involved in the present application can be better understood by referring to the exemplary embodiments and drawings described in detail below. The drawings are briefly described as follows:

[0009] Figure 1 Shown is a schematic structural diagram of a 3D printing device in one embodiment of the present application.

[0010] Figure 2 Shown is a schematic structural diagram of a forming platform in one embodiment of the present application.

[0011] Figure 3 Shown is a schematic diagram of the structure of a powder spreading system in one embodiment of the present application.

[0012] Figure 4 and Figure 5 They are schematic diagrams of the first powder return tank in one embodiment of the present application.

[0013] Figure 6 Shown is a schematic diagram of a powder return detection mechanism detecting the powder surface distance in one embodiment of the present application.

[0014] Figure 7 It is a schematic diagram showing the forming area before the flattening stage in one embodiment of the present application.

[0015] Figure 8 Shown is a schematic diagram of the powder spreading operation during the leveling stage in one embodiment of the present application.

[0016] Fig. 9 It is a schematic diagram showing the lower limit distance of the detection slot of the powder return detection mechanism in one embodiment of the present application.

[0017] Fig.10 It is a schematic diagram showing the molding area after flattening in one embodiment of the present application.

[0018] Fig.11 Shown is a schematic diagram of the powder spreading operation during the printing stage in one embodiment of the present application.

[0019] Fig.12 and Fig.13 They are respectively shown as schematic diagrams of the structure of the powder return detection mechanism in one embodiment of the present application at different viewing angles.

[0020] Fig.14 Shown is a cross-sectional schematic diagram of a powder return detection mechanism in one embodiment of the present application.

[0021] Fig.15 Shown is a schematic diagram of the split structure of the second base in one embodiment of the present application.

[0022] Fig.16Shown is a cross-sectional schematic diagram of a cooling mechanism in one embodiment of the present application.

[0023] Fig.17 It is a schematic diagram showing that the cooling bodies are connected in series in one embodiment of the present application.

[0024] Fig.18 It is a schematic diagram showing that the cooling bodies are connected in parallel in one embodiment of the present application.

[0025] Fig.19 Shown is a schematic diagram of a gas guiding structure in one embodiment of the present application.

[0026] Fig. 20 Display as Fig.19 A schematic cross-sectional view of a gas guiding structure in the illustrated embodiment.

[0027] Fig.21 Display as Fig.19 A partial enlarged schematic diagram of the gas guiding structure in the illustrated embodiment.

[0028] Fig. 22 Shown is a schematic diagram of a gas guiding structure in another embodiment of the present application.

[0029] Fig.23 Shown is a schematic structural diagram of a second material receiving assembly in one embodiment of the present application.

[0030] Fig.24 and Fig.25 They are respectively shown as schematic diagrams of the structure of the second material receiving hopper in different embodiments of the present application.

[0031] Fig.26 Shown is a schematic diagram of the state of the second material receiving hopper in the reverse powder spreading operation in one embodiment of the present application.

[0032] Fig. 27 Shown is a schematic structural diagram of a door assembly in one embodiment of the present application.

[0033] Figures 28 to 30 They are respectively shown as schematic diagrams of the process in which the second material receiving hopper passes through the first material receiving component and docks with the first material receiving component in one embodiment of the present application.

[0034] Fig.31 Shown is a schematic diagram of a connecting member in one embodiment of the present application.

[0035] Fig.32 Shown is a schematic diagram of a first material receiving component in one embodiment of the present application.

[0036] Fig.33 It is a cross-sectional schematic diagram showing the second material receiving hopper docking with the first material receiving assembly in one embodiment of the present application.

[0037] Fig.34 Show this application Fig.33 A local enlarged schematic diagram of point A in the illustrated embodiment.

[0038] Fig.35 and Fig.36 They respectively show cross-sectional schematic diagrams of a powder spreading device in one embodiment of the present application at different viewing angles.

[0039] Fig.37 and Fig.38 They respectively show cross-sectional schematic diagrams of a powder spreading device in another embodiment of the present application at different viewing angles.

[0040] Fig.39 Shown is a schematic structural diagram of the first scraper in one embodiment of the present application.

[0041] Fig.40 It is a schematic diagram showing the split structure of the first scraper relative to the second base in one embodiment of the present application.

[0042] Fig.41 It is a schematic diagram showing that the first scraper is configured in the installation space in one embodiment of the present application.

[0043] Fig.42 It is a schematic diagram showing the contact between the first blade portion and the powder spreading roller in one embodiment of the present application.

[0044] Fig.43 Shown is a schematic structural diagram of a third scraper in one embodiment of the present application.

[0045] Fig.44 It is a schematic diagram showing that the second scraper and the third scraper are arranged on the second base in one embodiment of the present application.

[0046] Fig.45 It is a schematic diagram showing that the third blade portion is in line contact with the powder spreading roller in one embodiment of the present application.

[0047] Fig.46 It shows a schematic diagram of the split structure of the third scraper and the side support plate in one embodiment of the present application. DETAILED DESCRIPTION

[0048] The following specific embodiments are used to illustrate the embodiments of the present application, and those familiar with the technology can easily understand the advantages of the present application and the technical effects that can be achieved by the content disclosed in this specification. In the following description, some embodiments can refer to the accompanying drawings. It should be understood that other embodiments without drawing drawings can also be used, and specific structures, parts or mechanisms, components and operational changes can 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 limited only by the claims published in the present application. The terms used here are only for describing specific embodiments and are not intended to limit the present application.

[0049] It should be understood that, although the term first, second or third etc. can be used to describe various elements or parameters in this article in some embodiments, these elements or parameters should not be limited by these terms.These terms are only used to distinguish an element or parameter from another element or parameter, and are not used to limit the order, priority or the importance of multiple elements.For example, the first pick-up assembly can be referred to as the second pick-up assembly, and similarly, the second pick-up assembly can be referred to as the first pick-up assembly, and does not break away from the scope of various described embodiments.

[0050] Furthermore, as used in this article, the singular forms "one", "an" and "the" are intended to also include plural forms, unless there is an indication to the contrary in the context. It should be further understood that the terms "comprising", "including" indicate the presence of the described features, steps, operations, elements, components, projects, kinds, and / or groups, but do not exclude the presence, occurrence or addition of one or more other features, steps, operations, elements, components, projects, kinds, and / or groups. For example, the process, method, system, product or equipment comprising a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment. In addition, the term "and / or" that may be used hereinafter, describes the association relationship of associated objects, indicating that three kinds of relationships may exist, for example, A and / or B, which can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / ", if not otherwise specified, generally represents that the associated objects before and after are a kind of "and / or" relationship. In addition, in the description of the embodiments of the present application, "multiple" refers to two or more than two. Furthermore, the terms "or" and "and / or" used in this document are interpreted as inclusive, or mean any one or any combination. Exceptions to this definition will only occur when a combination of elements, functions, steps or operations are 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 "to" another element "above", the element may be directly on another element or directly extend to another element, or there may also be an intermediate element. Conversely, when an element is referred to as being "directly on" another element or "directly extending to" another element "above", there are no intermediate elements. It will also be understood that when an element is referred to as being "connected" or "coupled" to another element, it may be directly connected or coupled to another element, or there may be an intermediate element. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intermediate elements. In addition, the term "coupled" generally means physical, mechanical, magnetic, and / or electrical coupling or connection, and in the absence of specific contrary language, does not exclude the presence of intermediate elements between items that are 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 figure. It will be understood that these terms are intended to cover different device orientations other than the orientation depicted in the figure. In this application, the "vertical", "horizontal" and "parallel" are defined as: including the situation of ±10% on the basis of the standard definition. For example, vertical usually refers to an angle of 90° relative to the reference line, but in this application, vertical refers to the situation within 80° to 100°. Unless otherwise explicitly stated, comparative quantitative terms (such as "above" and "below") are intended to cover the concept of equality. As an example, "above" can not only mean "greater than" in a mathematical sense, but also "equal to".

[0053] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application. When used herein, the singular forms "a", "an", and "the" are intended to also include the plural forms unless the context clearly indicates otherwise. It will also be understood that when used herein, the terms "comprise", "include", "include" and / or "comprising" specify the presence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the presence or increase of one or more other features, integers, steps, operations, elements, parts and / or combinations thereof.

[0054] In view of the technical problems mentioned in the background technology, the present application discloses a 3D printing device and a powder spreading system thereof, wherein 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 molding 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 molding chamber, the first material receiving component and the second material receiving component can be docked when the powder spreading roller moves toward the first area, so that the powder is buffered in the second material receiving component. In addition, when the powder spreading roller moves toward 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 and ensuring the molding environment in the molding chamber.

[0055] In the present application, the 3D printing device is a device that uses powder as 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) and 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] Thermoplastic elastomers are a type of elastomer that has the elasticity of rubber at room temperature and can be plasticized and molded at high temperatures. They are physical mixtures of copolymers or polymers (usually plastics and rubbers) and are composed of materials with thermoplastic and elastomeric properties. Generally, thermoplastics are relatively easy to use in manufacturing, such as by injection molding.

[0057] In some embodiments, the powder can 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, or an SHS type 3D printing device, etc. In the following embodiments, the 3D printing device is an SLS type 3D printing device as an example for description.

[0059] For SLS (Selective Laser Sintering) equipment, 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 of preset power and stop emitting the laser beam. For another example, the laser emitter is controlled to increase the power of the laser beam and reduce the power of the laser beam. The flat-field focusing lens is used to adjust the focus position of the laser beam, and the galvanometer system is used to control the laser beam to scan the two-dimensional space of the printing reference surface of the powder bed. The powder material scanned by the beam is sintered into a corresponding pattern sintering layer.

[0060] The component platform of the SLS equipment is set in the powder bed or sintering molding chamber containing powder materials, and is used to attach and accumulate the pattern sintering layer after irradiation and sintering. After the powder bed is laid, the powder material to be sintered is heated to a temperature just below the sintering point of the powder through the constant temperature facility in the printing equipment, and the three-dimensional model slices of the printed component are printed by laser tracking of the optical system, and the slices are copied on the powder bed with the corresponding image, so that the powder material is heated to above the melting point under laser irradiation to achieve sintering, and printing is achieved with the corresponding layer height of the slices. After one layer is built, the powder bed drops accordingly, and the corresponding next slice pattern is built on the existing sintering layer, and the above process is repeated until printing is completed.

[0061] See also Figure 1 , which is a schematic diagram of the structure of a 3D printing device in one embodiment of the present application, such as Figure 1 As shown, the 3D printing device includes a molding platform 1, a powder spreading system 2, an optical system 3, and a control device 4. The molding platform 1 has a molding area (not shown in the figure), and a component mechanism 10 that can move layer by layer in the vertical direction is arranged corresponding to the molding area. The powder spreading system 2 is used to spread powder in the molding area. The optical system 3 is used to emit a light beam to irradiate the powder in the molding 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 powder in the molding area during the printing operation, control the optical system 3 to irradiate the powder in the molding 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 aforementioned embodiment, wherein the laser emitter may be a fiber laser, a YAG laser, etc., and the galvanometer system may be deflected under the drive of its drive motor. For example, the drive motor of the scanning galvanometer is controlled by the control instruction 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 to any position on the printing reference surface.

[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 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 a device independently installed in a 3D printing device such as an optical system, a component mechanism, a powder spreading system, and transmits data through an interface. The control device also includes at least one of the following: a prompt device, a human-computer interaction device, etc. The interface unit determines its interface type according to the connected device, which includes but is not limited to: a universal serial interface, a video / image interface, and an industrial control interface, etc.

[0064] See also Figure 2 , which is a schematic diagram of the structure of a molding platform in one embodiment of the present application. Figure 2 As shown, the molding platform 1 has a molding area 11, and a first area 12 and a second area 13 located on opposite sides of the molding area 11. Figure 2 In the example, the first area 12 corresponds to the spatial area on the left side of the molding area 11, and the second area 13 corresponds to the spatial area on the right side of the molding area 11, which is not a restriction on the orientation of the first area 12 and the second area 13.

[0065] It should be noted that, in the following embodiments, in order to clearly illustrate the relative positions of various components, structures, assemblies, mechanisms, components, equipment, or devices in the printing device, the first area 12 and the second area 13 of the forming platform 1 are used as references for distinction, and the side of each component, structure, assembly, mechanism, component, equipment, or device 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 In the example, the first area 12 is located on the left side and the second area 13 is located on the right side. Therefore, in the subsequent embodiments, the first side is also referred to as the left side and the second side is also referred to as the right side.

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

[0067] In one embodiment, if Figure 2 As shown, the molding area 11 is set as a space area that passes through the molding platform 1, the first area 12 is located on the left side of the space area, and the second area 13 is located on the right side of the space area. In some examples, the shape of the molding area can be a cube, a cuboid, or other shapes, and its shape and size determine the range of manufacturing and forming 3D components that the 3D printing device can provide. For example, if the size of the molding area is 600 mm×600 mm×400 mm, the maximum range of 3D components that the 3D printing device can print is no more than 600 mm×600 mm×400 mm.

[0068] In one embodiment, if Figure 1 The arrangement of the component mechanism 10 corresponding to the molding area 11 refers to the arrangement of the component mechanism 10 with the component surface facing the molding area 11 to cooperate with the molding area 11 to form a component space. Figure 2 Taking the molding platform 1 shown as an example, the component mechanism 10 is located on the lower side of the molding area 11 in a manner capable of closing the bottom opening of the molding area 11, and the top opening of the molding area faces the optical system, so that the component mechanism 10 can form a component space with the molding area 11 having an opening toward the optical system to receive the emitted light beam.

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

[0070] In one embodiment, the component mechanism 10 may be configured to include a warehouse body, a component platform, and a Z-axis moving mechanism connected to the component platform. The warehouse body is arranged at the lower side of the molding area in such a way that its entrance is butted against the bottom opening of the molding area. The component platform is arranged in the warehouse body to form a component space for printing 3D components together with the warehouse body and the molding area. During printing, the component platform is driven by the Z-axis driving mechanism to move vertically in the warehouse body to adjust the distance from the printing reference plane (it can also be understood as adjusting the volume of the component space), so that the sintered layers formed by the optical system can be accumulated layer by layer, and finally a 3D component is formed.

[0071] In one embodiment, the component platform is closely attached to the inner wall of the bin body, and its vertical movement driven by the Z-axis drive mechanism during printing can be understood as moving upward or downward in the bin body. In some examples, the component plate has a heat conduction function so that the bin body and the molding chamber can be maintained at 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, and the driving unit is used 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 the control instruction output by the control device. Among them, the control instruction includes: a directional instruction for indicating that the component plate rises, falls or stops, and may even include parameters such as speed / speed acceleration, or torque / torque. This is conducive to accurately controlling 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 fixed at one end to the component plate and an interlocking moving component fixed to the other end of the fixed rod, wherein the interlocking moving component is driven by the driving unit to drive the fixed rod to move along the Z-axis direction, and the interlocking moving component is exemplified by a limit moving component engaged by a toothed structure, such as a rack. For another example, the Z-axis moving unit includes: a screw and a positioning and moving structure screwed to the screw, wherein both ends of the screw are screwed to the drive unit, and the outer end of the positioning and moving structure is fixedly connected to the component plate. The positioning and moving structure can be, for example, a ball screw.

[0073] See also Figure 3 Combined with Figure 2 ,in, Figure 3 The schematic diagram of the structure of the powder spreading system in one embodiment of the present application is shown. Figure 2 and Figure 3 As shown, the powder spreading system 2 includes a powder spreading device 22 for being driven to move back and forth between the first area 12 and the second area 13 to perform powder spreading operations on the building platform 1 .

[0074] In one embodiment, each powder spreading operation includes a forward powder spreading operation and a reverse powder spreading operation, wherein the forward powder spreading operation is defined as the powder spreading device 22 moving from the first area to the second area (in a manner such as Figure 2 The reverse powder spreading operation is defined as the powder spreading device 22 moving from the second position toward the first area (in the direction indicated by Y in the figure, also referred to as forward movement). Figure 2 It should be noted that each powder spreading operation including forward powder spreading operation and reverse powder spreading operation is only an example. In other embodiments, each powder spreading operation may also include only forward powder spreading operation. For example, when performing the return movement, the powder spreading system can be lifted to a point where it does not contact the forming platform and only returns without spreading powder. In the subsequent embodiments, each powder spreading operation including forward powder spreading operation and reverse powder spreading operation will be used as an example for explanation, and it is not to be understood as a limitation on the present application.

[0075] In one embodiment, an initial position may be set in the first area 12, and a return position may be set in the second area 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, the operation from the initial position to the return position may be referred to as a forward powder spreading operation, and the operation from the return position to the initial position may be referred to as a reverse powder spreading operation. 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 of the powder spreading device 22 completing the powder spreading in one direction starting from the starting position.

[0076] In one embodiment, if Figure 2 As shown, a first powder return groove 14 is provided on the first area 12 of the molding platform 1, and when the powder spreading device 22 moves back to the first area 12, the excess powder can be pushed into the first powder return groove 14. In one example, the first powder return groove 14 is further located on the right side of the initial position, and when the powder spreading device 22 performs reverse powder spreading operation and moves to the initial position, the powder spreading device 22 will pass through the first powder return groove 14, so that the excess powder can be pushed into the first powder return groove 14. In this example, the first powder return groove 14 can also be lifted to be flush with the upper surface of the molding platform, and when the powder spreading device 22 performs forward powder spreading operation, the powder can be smoothly pushed from the first powder return groove 14 to the molding area 11.

[0077] For further information, see Figure 4 and Figure 5 , respectively, are schematic diagrams showing the first powder return tank in one embodiment of the present application, such as Figure 4 and Figure 5 As shown, the first powder return tank 14 includes a tank bottom plate 142 connected to the first lifting assembly 141, and the tank bottom plate 142 is driven by the first lifting assembly 141 to a first position P that is flush with the molding platform 1. 1 The powder spreading device 22 is provided to pass through when it moves to the second area 13, and after the powder spreading device 22 passes through the bottom plate 142, it is driven by the first lifting assembly 141 to sink to the second position P of the molding platform 1. 2 That is to say, the first lifting assembly 141 can drive the trough bottom plate 142 to perform lifting movement, so that the trough bottom plate 142 is located at the first position P 1 When the bottom plate 142 of the trough is at the second position P, the powder spreading device 22 may be allowed to pass through to perform a forward powder spreading operation. 2 When the powder spreading device 22 is performing reverse powder spreading operation, it can receive excess powder generated during the powder spreading process.

[0078] In one embodiment, the first position P 1The second position P is flush with the upper surface of the forming platform 1, which allows the powder spreading device 22 to pass through unhindered during the forward powder spreading operation, and can push the powder in the first powder return groove 14 onto the upper surface of the forming platform to replenish the powder amount during the forward powder spreading operation of the powder spreading device. 2 The first lifting assembly 141 can be arranged at the bottom of the first powder return trough 14 to form a space S that can accommodate powder, so that the powder spreading device 22 can push excess powder into the space S when performing reverse powder spreading. It should be understood that the volume provided by the space S determines the maximum capacity of the first powder return trough 14 that can accommodate powder. In this embodiment, the first lifting assembly 141 can drive the trough bottom plate 142 to move to the first position P 1 Or the second position P 2 , respectively presented as Figure 4 and Figure 5 status.

[0079] In one embodiment, the first lifting assembly 141 is disposed at the lower side of the trough bottom plate 142, and can be configured to include a first lifting shaft and a first lifting drive unit, wherein the first lifting shaft is connected to the trough bottom plate 142, and the first lifting drive unit can be, for example, disposed at the bottom of the first lifting shaft and associated with the first lifting shaft to realize the movement of the trough bottom plate 142 to the first position P. 1 Or the second position P 2 .

[0080] In some examples, the first lifting shaft may be configured as a threaded rod, and the first lifting drive unit may be configured as a rotary motor. For example, the rotary motor drives the threaded rod to rotate forward to achieve the upward movement of the trough bottom plate 142, and the rotary motor drives the threaded rod to rotate reversely to achieve the downward movement of the trough bottom plate 142. In other certain examples, the first lifting shaft may be configured as a telescopic rod, and the first lifting drive unit may be configured as a lifting motor. For example, the lifting motor drives the telescopic rod to extend to achieve the upward movement of the trough bottom plate 142, and the lifting motor drives the telescopic rod to retract to achieve the downward movement of the trough bottom plate 142. Of course, in other certain embodiments, the first lifting component 141 may also be configured in other forms, as long as it can drive the trough bottom plate 142 to perform lifting and lowering movements. In some examples, the first lifting component 141 may also include a limiting portion to prevent the trough bottom plate 142 from rising to the first position P. 1 or descend to the second position P 2 excessive movement.

[0081] In one embodiment, if Figure 2As shown, a second powder return groove 15 is provided on the second area 13 of the molding platform 1. In one example, the second powder return groove 15 is further located on the left side of the return position, and when the powder spreading device 22 moves from the initial position toward the return position to complete the forward powder spreading operation, the excess powder can be sent to the second powder return groove 15. In this example, the second powder return groove 15 can also be lifted to be flush with the upper surface of the molding platform, and during the reverse powder spreading operation of the powder spreading device 22, the powder can be smoothly pushed from the second powder return groove 15 to the molding 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 a second lifting assembly, wherein the second lifting assembly can also be configured to have the same structure as the first lifting assembly 141. For details, please refer to the description of the first powder return trough 14 in the aforementioned embodiment, which will not be repeated here.

[0083] Specifically, the bottom plate of the second powder return tank 15 is driven by the second lifting assembly to sink to the second position P on the molding platform 1. 2 The second lifting assembly is used to receive the powder pushed in by the powder spreading device 22 when it moves to the second area 13, and the powder spreading device 22 is driven by the second lifting assembly to the first position P that is flush with the molding platform 1 after passing through the bottom plate of the trough. 1 To push the received powder to a forming platform.

[0084] The following combination Figure 2 , Figure 4 ,and Figure 5 The process of completing a powder spreading operation is described below. The powder spreading device 22 first moves from the initial position to the return position to perform a forward powder spreading operation. At this time, the first lifting assembly 141 drives the bottom plate 142 of the first powder return trough 14 to rise to the first position P 1 The powder spreading device 22 passes through and continues to pass through the molding area 11 to spread powder in the molding area 11. Before the powder spreading device 22 moves to the second powder return trough 15, the second lifting assembly drives the bottom plate of the second powder return trough 15 to descend to the second position P. 2 When the powder spreading device 22 moves from the return position to the initial position to perform the reverse powder spreading operation, the second lifting assembly drives the bottom plate of the second powder return trough 15 to rise to the first position P 1 The powder spreading device 22 passes through the molding area 11 and continues to spread powder in the molding area 11. Before the powder spreading device 22 moves to the first powder return trough 14, the first lifting assembly 141 drives the bottom plate 142 of the first powder return trough 14 to descend to the second position P. 2To 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, if Figure 2 As shown, the first area 12 is also provided with a powder overflow port 16 located on the first side of the first powder return groove 14. As mentioned above, the volume provided by the space S in the first powder return groove 14 determines the maximum capacity of the powder that the first powder return groove 14 can receive. Therefore, if the amount of excess powder when the powder spreading device 22 completes a powder spreading operation is greater than the maximum capacity of the first powder return groove 14, the powder spreading device 22 will continue to drive the excess powder exceeding the maximum capacity of the first powder return groove 14 to move toward the powder overflow port 16 when passing through the first powder return groove 14, so as to recover the excess powder with the help of the powder overflow port 16. Further, in some examples, a powder recovery mechanism may be provided at the lower side of the powder overflow port 16 to recover the excess powder.

[0086] The powder laying operation described in the present application may be a powder laying operation in the flattening stage or a powder laying operation in the printing stage, wherein the flattening stage refers to the process of filling the bottom surface in the molding area before formal printing, and the printing stage refers to the process of using the emission light beam of the optical system to shape the powder layer by layer to construct a 3D component layer by layer.

[0087] It should be noted that the powder spreading operation in the paving stage is closely related to the quality of the printed 3D components. For example, if printing is started before the paving stage is completed, pores or cracks will appear in the 3D components. However, in the related art, operators usually use their naked eyes to judge whether the paving stage is completed, which is inefficient and inaccurate. In addition, the powder spreading operation in the printing stage is usually quantitative powder supply, which cannot adjust the powder supply in time according to parameters such as the thickness of the printing layer and the printing speed, which will cause problems such as excessive waste of powder supply or insufficient supply that cannot ensure the smooth progress of the printing process.

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

[0089] In one embodiment, the powder return detection mechanism 23 is disposed on the top of the upper shell 17 to project a laser toward the first powder return groove 14 to detect the powder surface distance. In one example, a first opening is disposed on the upper shell 17, and the powder return detection mechanism 23 is fixed on the upper shell with its emitting portion facing the opening, so that the laser projected by the powder return detection mechanism 23 can pass through the upper shell 17 and enter the first powder return groove 14, thereby realizing the detection of the powder surface distance. In this example, a second opening can also be provided on the upper shell 17 for arranging the optical system 3 and allowing the light beam emitted by the optical system 3 to pass through and be projected onto the molding area 11.

[0090] In one embodiment, the powder surface distance is reflected by the length of the laser emitted by the powder return detection mechanism 23 to the first powder return groove 14. Figure 6 , which is a schematic diagram showing the powder return detection mechanism detecting the powder surface distance in one embodiment of the present application, Figure 6 In the figure, a small dot indicates the powder return detection mechanism 23, and a straight line extending from the small dot indicates the laser emitted by the powder return detection mechanism 23. Figure 6 In the example shown, the powder surface distance corresponds to the emitted laser length L. It should be noted that the surface of the powder in the first powder return tank 14 is not necessarily the same as Fig. 9 The illustrated inclined surface, based on the randomness of the powder falling into the first powder return groove 14, the surface of the accumulated powder can be in any shape, for example, in an arc shape or an irregular shape. In these examples, the powder surface distance is the laser length L.

[0091] The following combination Figures 7 to 10 The powder return detection mechanism 23 is used to determine whether the flattening stage of the molding platform 1 is completed.

[0092] See also Figure 7 , which is a schematic diagram of the molding area before the flattening stage in one embodiment of the present application, as shown in Figure 7 As shown, the powder in the forming area 11 is not flat, for example, there may be holes, local accumulation or gaps on the powder layer, so it needs to be leveled. Figure 8 , which is a schematic diagram of the powder spreading operation in the flattening stage in one embodiment of the present application, such as Figure 8 As shown, when the powder spreading device 22 is used for the first forward powder spreading operation, the powder amount can be spread to M 1 At this time, all the powder is pushed to the forming area 11 and is not enough to completely fill the holes or gaps on the inner powder layer. Therefore, no excess powder will be pushed into the first powder return groove 14 during the reverse powder spreading operation. Figure 8 As shown in the figure, during the second, third, fourth and fifth powder spreading operations, the powder amount can be spread to M respectively. 2 、M3 、M 4 、M 5 The forming area 11 can be leveled only by applying powder several times.

[0093] Depending on the amount of powder or the filling area, the number of times the powder spreading device 22 needs to complete the 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 groove 14 based on the powder surface distance L measured by the powder return detection mechanism 23.

[0094] In one embodiment, whether there is powder in the first powder return trough 14 can be determined based on the measured powder surface distance L and a reference distance, wherein the reference distance can be determined by a trough lower limit distance. Figure 5 Combination Fig. 9 As shown in the example, Fig. 9 The figure shows a schematic diagram of the lower limit distance of the detection slot of the powder return detection mechanism in one embodiment of the present application, wherein the lower limit distance of the slot is the distance when the slot bottom plate 142 is located at the second position P. 2 The laser length L 2 In some examples, the reference distance can be set to the lower limit distance of the slot, or slightly less than the lower limit distance of the slot. When the powder surface distance L is less than the reference distance, the powder has exceeded the second position P. 2 , it can be determined that there is powder in the first powder return groove 14, that is, it can be determined that the molding area has been paved, and the state after paving is as follows Fig.10 As shown, Fig.10 It is a schematic diagram of the molding area after the paving is completed in one embodiment of the present application, so that the subsequent printing stage can be entered.

[0095] The following combination Fig.11 The powder return detection mechanism 23 is used to determine the powder supply amount for the next powder spreading operation.

[0096] See also Fig.11 , which is a schematic diagram of the powder spreading operation in the printing stage in one embodiment of the present application. Fig.11 As shown, after the paving is completed, the aforementioned component plate can be driven by the Z-axis driving mechanism to drop to a height of a printing layer. 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 spread in the forming area 11. Then, the optical system can emit a light beam to form the powder layer.

[0097] In order to ensure that the amount of powder dropped can match the amount of powder laid on each layer, the powder return detection mechanism 23 can be used to detect the powder surface distance L of the first powder return groove 14 when the powder laying device 22 completes a round trip movement to determine the powder supply amount for the next powder laying operation. Specifically, when the detected powder surface distance L indicates that the powder supply amount of this powder laying operation is large, the powder supply amount of the next powder laying operation should be reduced; when the detected powder surface distance L indicates that the powder supply amount of this powder laying operation is small, the powder supply amount of the next powder laying operation should be increased. In some implementations, the powder supply amount can be adjusted by 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 laying system 2 to adjust the powder supply amount according to the control instruction. In some examples, the powder supply amount can be adjusted by adjusting the quality or number of 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 of the next powder spreading operation can be determined based on the measured powder surface distance L and a reference powder surface distance interval. For example, when the measured powder surface distance L is less than the minimum value of the reference powder surface distance interval, the powder supply amount of 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 interval, the powder supply amount of the next powder spreading operation can be increased; when the measured powder surface distance L is within the reference powder surface distance interval, the powder supply amount of the next powder spreading operation can be left unchanged.

[0099] In one embodiment, the reference powder surface distance interval can be determined based on the slot lower limit distance and the slot upper limit distance. The slot lower limit distance and the slot upper limit distance can both be detected by the powder return detection mechanism 23. Figure 4 , Figure 5 ,and Fig. 9 As shown, the powder return detection mechanism 23 can respectively detect the bottom plate 142 of the groove at the first position P 1 The corresponding slot upper limit distance L 1 and the bottom plate 142 is in the second position P 2 The corresponding slot lower limit distance L 2 .

[0100] Specifically, when determining the reference powder surface distance interval, the lower limit distance L of the groove can be firstly 2 and the upper limit distance L of the groove 1 A reference value is determined, and then the reference powder surface distance interval is obtained from the reference value. For example, the reference value may be the lower limit distance L of the groove 2 and the upper limit distance L of the slot 1The reference powder surface distance interval is the average value or a numerical interval expanded up and down with the average value as the reference value. 1 50mm, slot lower limit distance L 2 When the average value is 100mm, the average value of the two is 75mm. The average value is used as the benchmark powder surface distance interval, which is 75mm. The average value is used as the benchmark value to expand up and down by 5%, which is [71.25,78.75].

[0101] See also Figure 12 to Figure 14 ,in, Fig.12 and Fig.13 They are schematic diagrams of the structure of the powder return detection mechanism in one embodiment of the present application at different viewing angles, Fig.14 The figure shows a cross-sectional schematic diagram of a powder return detection mechanism in one embodiment of the present application. Figure 12 to Figure 14 As shown, the powder return detection mechanism 23 includes a base 231 and a rangefinder 232. The base 231 is arranged on the top of the upper shell 17, and has an optical channel 2311 that runs through the upper and lower parts to connect to the molding chamber. The rangefinder 232 is arranged on the base 231 to project laser light toward the first powder return groove 14 through the optical channel 2311 and receive 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 first base 231 and the second base 221 will not be repeated later.

[0102] In one embodiment, the rangefinder 232 is configured as a laser rangefinder sensor, including a transmitter and a receiver, wherein the transmitter is used to project laser light toward the first powder return groove 14 through the optical channel 2311 , and the receiver is used to receive light reflected from the first powder return groove 14 .

[0103] See also Fig.15 , which is a schematic diagram of the split structure of the first base in one embodiment of the present application, such as Fig.15 As shown, the first base 231 includes a base plate 2312 fixed to the top of the upper housing 17 and a seat body 2313, the base plate 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 one example, the seat body 2313 is mounted on the mounting surface 23121 by a toggle clamp. In this example, please refer to Fig.14The optical channel 2311 includes a lower opening 23111 formed in the base plate 2312 and an upper opening 23112 formed in the seat body 2313. The lower opening 23111 and the upper opening 23112 are interconnected to ensure that the laser projected into the first powder return groove 14 is not blocked.

[0104] In one embodiment, if Fig.15 As shown, the seat body 2313 is generally a rectangular parallelepiped, 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 seat body 2313 is obliquely 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 obliquely projected from the optical channel 2311 into the first powder return groove 14.

[0105] It should be understood that the molding chamber may be provided with devices or components such as a powder spreading device 22 or an optical system, and the tilted setting 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 groove 14. In addition, if the laser projected by the rangefinder 232 is vertically projected onto the first powder return groove 14, it will affect the reception of the reflected light by the receiving unit. Therefore, the tilted posture of the rangefinder 232 can ensure the continuity of the light path and the accuracy of the acquired reflected light signal.

[0106] It should be noted that the high temperature environment in the molding chamber may also affect the normal operation of the rangefinder 232. In view of this, in one embodiment, Fig.12 As shown, the powder return detection mechanism 23 further includes a cooling mechanism 233 disposed on the first base 231, and the cooling mechanism 233 is attached to the distance meter 232 for cooling. In some examples, the cooling mechanism 233 can use a coolant or a gas to cool the distance meter 232.

[0107] In one embodiment, the cooling mechanism 233 includes at least one cooling body having a liquid inlet and a liquid outlet, and a cooling passage connecting the liquid inlet and the liquid outlet is provided in the cooling body for the cooling liquid to pass through.

[0108] In one embodiment, the cooling body is provided as two cooling bodies respectively attached to the two opposite side walls of the rangefinder 232. Fig.12 and Fig.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. Fig.12 As 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 Fig.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 Fig.16 shown, the first cooling body 2331 has a first liquid inlet 23311 and a first liquid outlet 23312. A first cooling passage 23313 communicating the first liquid inlet 23311 and the first liquid outlet 23312 is provided inside the first cooling body 2331 for the coolant to pass through. That is, the coolant flows through the first cooling passage 23313 via 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 the interfaces for the coolant to enter and exit the first cooling body 2331 respectively. 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 Fig.17 , which shows a schematic diagram of each cooling body connected in series in an embodiment of the present application. As Fig.17As shown, the first cooling body 2331 is provided with a first liquid inlet 23311 and a first liquid outlet 23312, and the second cooling body 2332 is provided with a second liquid inlet 23321 and a second liquid outlet 23322. In one example, the liquid inlet pipeline is connected to the first liquid inlet 23311, and the liquid outlet pipeline is connected to the second liquid outlet 23322. In this example, the flow path C of the coolant is as follows Fig.17 In the direction indicated by the middle arrow, specifically, the coolant is input into the first liquid inlet 23311 through the liquid inlet pipeline, output to the first liquid outlet 23312 through the cooling passage in the first cooling body 2331, and then input into the cooling passage of the second cooling body 2332 through the second liquid inlet 23321 connected to 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. Fig.18 , which is a schematic diagram showing that the cooling bodies are connected in parallel in one embodiment of the present application. Fig.18 As shown, the first cooling body 2331 is provided with a first liquid inlet 23311 and a first liquid outlet 23312, and the second cooling body 2332 is provided with a second liquid inlet 23321 and a second liquid outlet 23322. In one example, the liquid inlet pipeline is respectively connected to the first liquid inlet 23311 and the second liquid inlet 23321, and the liquid outlet pipeline is respectively connected to the first liquid outlet 23312 and the second liquid outlet 23322. In this example, the flow path of the coolant includes the first flow path B connected in parallel with each other. 1 and the second flow path B 2 , specifically as Fig.18 In the direction indicated by the arrow. That is, the coolant is simultaneously inputted into the first liquid inlet 23311 and the second liquid inlet 23321 from the liquid inlet pipeline to simultaneously enter the first cooling body 2331 and the second cooling body 2332, and after flowing through the respective cooling passages, is outputted to the liquid outlet pipeline from 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 and printing stages, some of the powder in the molding chamber may be blown up to form smoke. When the density of the smoke 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 Fig.14 and Fig.15As shown in the figure, the upper opening 23112 of the light channel 2311 is covered with a light-transmitting protective plate 23113, and the rangefinder 232 is located on the light-transmitting protective plate 23113. In this embodiment, the light-transmitting protective plate 23113 can be used as a physical barrier to block the powder, thereby ensuring the measurement accuracy. In some examples, the light-transmitting protective plate 23113 can be configured as a plexiglass plate. In some examples, the surface of the light-transmitting protective plate 23113 can be coated with an anti-reflection coating to reduce the reflection loss of the laser on the surface of the light-transmitting protective plate 23113.

[0115] In one embodiment, if Fig.14 As shown, a gas guiding structure 2314 connected to the upper opening 23112 is formed in the first base 231, and the gas guiding structure 2314 is used to guide the airflow from the cleaning mechanism to the bottom of the light-transmitting protective plate 23113 to clean the light-transmitting protective plate 23113. In this embodiment, the airflow of the cleaning mechanism can clean the dirt attached to the light-transmitting protective plate to avoid affecting the rangefinder 232 from receiving the reflected light signal. 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 protective 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 under the high temperature environment in the molding 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 protective plate 23113.

[0116] See also Fig.19 and Fig. 20 ,in, Fig.19 It is a schematic diagram of a gas guiding structure in one embodiment of the present application. Fig. 20 Display as Fig.19 A schematic cross-sectional view of the gas guiding structure in the embodiment shown. Fig.19 and Fig. 20 As shown, the gas guiding structure 2314 includes a first air inlet channel 23141, a buffer chamber 23142, and an air outlet channel 23143 which are connected in sequence. Fig.21 , displayed as Fig.19 A partial enlarged schematic diagram of the gas guide structure in the embodiment shown is as follows: Fig.21 As shown, the airflow is filled into 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, if Figures 19 to 21As shown, the buffer chamber 23142 is configured as a groove opened in the adjacent area of ​​the light channel 2311, and the air outlet channel 23143 is configured to be formed by sinking a preset area connected between the opening of the groove and the upper opening 23112. The preset area refers to an area pre-demarcated in the connection area between the opening of the groove corresponding to the buffer chamber 23142 and the upper opening 23112, for example Fig. 20 The outer contour of the air outlet channel 23143 shown in the figure corresponds to the pre-defined area. It should be noted that the height 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 airflow flowing to the air outlet channel 23143 is sharply reduced, thereby facilitating the formation of the high-speed airflow F.

[0118] In one embodiment, if Fig.19 As shown, the air outlet channel 23143 includes a transition section T connected to the buffer chamber 23142 1 and an air outlet section T connected to the upper opening 23112 2 , the transition section T 1 Used to introduce the airflow into the air outlet section T 2 , air outlet section T 2 The width of the upper opening 23112 is not less than the width of the upper opening 23112 so that the air passing through the air outlet section T 2 The guided airflow can completely cover the upper opening 23112. In this example, the transition section T 1 Set to present as Fig.19 The trumpet-shaped part shown in FIG. 1 is used to expand the airflow, and the air outlet section T 2 Set to present as Fig.19 The rectangular portion shown in FIG. 23 is used to guide the airflow to the light channel 2311 .

[0119] In one embodiment, the first air inlet channel 23141 is used to connect to the first cleaning component in the cleaning mechanism to perform the first cleaning operation. The first cleaning component may be configured to include a gas compressor for inputting high-pressure gas into the first air inlet channel 23141 to perform the first cleaning operation. In one example, the gas may 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 may 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 protective plate works intermittently, and its working frequency may be, for example, once a day.

[0120] See also Fig. 22 , which is a schematic diagram of a gas guiding structure in another embodiment of the present application. Fig. 22As shown, the gas guiding structure 2314 also includes a second air inlet channel 23144 connected to the buffer chamber 23142, and the second air inlet channel 23144 is used to connect the second cleaning component in the cleaning mechanism to perform the second cleaning operation. The second cleaning component can be configured as an air pump, which is used to input an inert gas into the second air inlet channel 23144 to perform the second cleaning operation. In this embodiment, the second cleaning component can work continuously to continuously blow airflow under the light-transmitting protective plate 23113, thereby preventing powder from adhering to the light-transmitting protective plate 23113. In some examples, the static pressure of the gas under the light-transmitting protective plate 23113 can reach 50324Pa.

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

[0122] In one embodiment, if Figure 3 As shown, the powder spreading roller 2211 is arranged below the second base 221, and its axis is perpendicular to its translation direction. In this embodiment, the second base 221, as a bearing structure supporting the powder spreading roller 2211, can be configured as a rigid material such as alloy, stainless steel, etc. to provide rigid support for the powder spreading roller 2211, thereby reducing the uneven powder spreading 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 layers of powder and improve the compactness of the laid powder, so as to avoid printing defects such as holes or warping caused by loose powder. In one example, the powder spreading roller 2211 is configured as a high hardness and wear-resistant material such as hardened steel, composite ceramics or carbon fiber composite materials to resist friction loss with the powder.

[0123] In one embodiment, the first driving mechanism can drive the powder spreading roller 2211 to perform 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 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 toward the return position, and 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 toward the initial position, and at the same time, the second driving mechanism drives the powder spreading roller 2211 to rotate clockwise around its axis.

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

[0125] In one implementation, the second driving mechanism may be configured to include a rotating shaft and a second driving source, wherein the rotating shaft is disposed on the axis of the powder spreading roller 2211, and the second driving source is associated with the rotating shaft and is used to drive the powder spreading roller 2211 to rotate counterclockwise or clockwise. In one example, the second driving source is configured as a rotary motor.

[0126] As mentioned above, in order to prevent the powder roller from rolling and spreading powder, which causes uneven subsequent powder spreading, it is necessary to clean the powder roller in the powder spreading device in a timely manner. In some related technologies, a brush is usually used to scrape off the residual powder on the powder spreading roller. However, the cleaning power of the brush is limited, and it can only scrape off large particles of powder. Small particles of powder or sticky powder attached to the brush may be left behind by the bristles and cannot be scraped off, thereby affecting the subsequent powder spreading process. In addition, in some related technologies, a flexible part is used to scrape off the residual powder on the powder spreading roller. However, due to its soft material, the flexible part will cause some powder with a certain hardness to be embedded in it. As the powder spreading roller rotates, these harder powders will scratch 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, Fig.35 and Fig.36 They are schematic cross-sectional views of a powder spreading device in one embodiment of the present application at different viewing angles. Fig.37 and Fig.38 They are schematic cross-sectional views of a powder spreading device in another embodiment of the present application at different viewing angles. Figures 35 to 38 As shown, the powder spreading device 22 provided in the present application further includes a scraper assembly 24, which is arranged on the second base 221, and includes at least one scraper 241 arranged along the length direction of the powder spreading roller 2211 and in contact with the powder spreading roller 2211, and the scraper 241 is used to cooperate with the rotation of the powder spreading roller 2211 to scrape off the powder adhering to the powder spreading roller 2211. The scraper assembly 24 provided in the present application can use the scraper 241 to fit the surface of the powder spreading roller 2211 as a whole, thereby preventing the powder from being left behind. In addition, the design of the scraper 241 can also prevent the powder with a certain hardness from being embedded therein, 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 roller 2211 has a first stiffness, and the scraper 241 has a second stiffness, and the second stiffness is greater than the first stiffness. The stiffness refers to the ability of the powder roller 2211 or the scraper 241 to resist elastic deformation when subjected to force, and is used to characterize the ease with which the powder roller 2211 or the scraper 241 is deformed, and can also be understood as the relative hardness of the powder roller 2211 or the scraper 241. In this embodiment, the stiffness of the scraper 241 is greater than the stiffness of the powder roller 2211, which can be understood as the hardness of the scraper 241 is greater than the hardness of the powder roller 2211, which allows the scraper 241 to clean the powder roller 2211 more thoroughly. For example, it can further scrape off the highly adhesive powder that is melted or sintered during the molding process. In one example, the powder spreading roller 2211 is made of stainless steel, and the scraper 241 is made of tungsten steel, but this is not limited to the above, as long as the stiffness of the scraper 241 is greater than that of the powder spreading roller 2211 .

[0130] In one embodiment, please combine Figure 2 ,as well as Figures 35 to 38 The second base 221 includes a main frame 2212 and a side support plate 2213 arranged at the lower side of the main frame 2212. The main frame 2212 spans the molding area 11 opened on the molding 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 installed on the first mounting portion on the side support plate 2213.

[0131] In one implementation, the main frame 2212 may be in the shape of a door as a whole, so that it can move on the molding platform 1 while supporting the powder spreading roller 2211 and the scraper 241. In one example, the main frame 2212 may be configured to include a transverse plate and two longitudinal plates. Fig.35 and Fig.37 For example, a horizontal plate 22121 and a vertical plate 22122 connected to each other are shown. Fig.35 and Fig.37 As shown, a reinforcing portion 22120 is provided at the connection between 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. Fig.35 and Fig.37In the example shown, the side support plate 2213 is arranged on the lower side of the transverse plate 22121 to install 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 avoid hindering 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 connect to the powder spreading roller 2211 to enable the second driving mechanism to drive the powder spreading roller 2211 to rotate.

[0132] In one embodiment, if Fig.35 and Fig.36 As shown, the scraper assembly 24 is configured to include a scraper 241. Fig.37 and Fig.38 The scraper assembly 24 shown includes a scraper 241, which can be Fig.35 and Fig.36 The scraper 241 included is referred to as the first scraper 241, and will not be described in detail later when the first scraper 241 is mentioned. Fig.35 and Fig.36 As shown, the first scraper 241 is arranged on the powder spreading roller 2211 perpendicular to the central axis O of the molding platform 1. 1 It is used to scrape off the powder by cooperating with the rotation of the powder spreading roller 2211 during the forward movement or return movement of the second base 221.

[0133] In this example, the central axis O 1 The first scraper 241 is vertically arranged at the highest position of the powder spreading roller 2211 through the diameter of the cross section where the powder spreading roller 2211 is located. As mentioned above, when the powder spreading device 22 performs forward powder spreading operation, that is, the second base 221 is in the process of moving forward, the powder spreading roller 2211 rotates counterclockwise, at this time, the first scraper 241 can scrape off the powder remaining on the powder spreading roller 2211 and retain the powder on the right side of the first scraper 241, 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, the second base 221 is in the process of moving back, the powder spreading roller 2211 rotates clockwise, at this time, the first scraper 241 can scrape off the powder remaining on the powder spreading roller 2211 and retain the powder on the left side of the first scraper 241, and the scraped powder can continue to be used for the reverse powder spreading operation.

[0134] See also Fig.39 , which is a schematic diagram of the structure of the first scraper in one embodiment of the present application, such as Fig.39As shown, the first scraper 241 is wedge-shaped as a whole, and can be configured to include an integrally formed main body 2411 and a blade 2412. In order to distinguish them from the main body and blade included in the second scraper in subsequent embodiments, the main body 2411 and the blade 2412 included in the first scraper 241 can be respectively referred to as the first main body 2411 and the first blade 2412. In this example, the first main body 2411 can be used to install the first scraper 241 on the second base 221, and the first blade 2412 can be used to scrape away the residual powder on the powder spreading roller 2211.

[0135] See also Fig.40 Combined with Fig.36 ,in, Fig.40 The diagram is a schematic diagram of the split structure of the first scraper relative to the second base in one embodiment of the present application. Fig.40 As shown, the main frame 2212 opens an installation space 22123 for setting the first scraper 241 along the length direction of the powder spreading roller 2211, and 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 and contacts the powder spreading roller 2211.

[0136] It should be understood that in the embodiment where the stiffness of the first scraper 241 is greater than the stiffness of the powder spreading roller 2211, forcibly scraping off the powder particles adhering to the powder spreading roller that are difficult to scrape off by the first scraper 241 may easily cause surface damage to the powder spreading roller 2211. In addition, the powder particles may also be stuck between the first scraper 241 and the powder spreading roller 2211, thereby affecting the rotation of the powder spreading roller 2211, making it difficult for the powder spreading operation to proceed smoothly.

[0137] In view of this, please refer to Fig.41 , which is a schematic diagram showing a first scraper configured in an installation space in one embodiment of the present application. Fig.41 As 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 matter to pass through. The foreign matter may be, for example, agglomerated powder with strong adhesion attached to the powder spreading roller 2211. In this embodiment, the redundant space 22125 provides a passable escape space for the foreign matter. When the foreign matter contacts the first scraper 241 as the powder spreading roller 2211 rotates, the redundant space 22125 allows the first scraper 241 to be pushed by the foreign matter and temporarily shifted sideways to separate from the powder spreading roller 2211, and a space is reserved for the foreign matter to pass through smoothly, which avoids the first scraper 241 forcibly scraping off the foreign matter and causing scratches on the surface of the powder spreading roller 2211, and at the same time avoids the foreign matter from 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 2411 of the first scraper 241 to form redundant spaces 22125 on both sides of the front and rear of the first main body 2411. For example, when the powder spreading roller 2211 rotates counterclockwise to perform a forward powder spreading operation, the foreign matter will contact the right side of the first scraper 241 and push the first scraper 241 to cling to the left side of the channel, so that the first scraper 241 deviates toward the central axis O. 1 The left side of the first scraper 241 is separated from the powder spreading roller 2211 at the same time, so that the foreign matter passes through the redundant space on the right side of the first main body 2411. When the powder spreading roller 2211 rotates clockwise to perform reverse powder spreading operation, the foreign matter will contact the left side of the first scraper 241 and push the first scraper 241 to the right side of the channel, so that the first scraper 241 deviates to the central axis O. 1 The right side of the first main body 2411 is separated from the powder spreading roller 2211 at the same time, so that the foreign matter passes through the redundant space on the left side of the first main body 2411.

[0139] In one embodiment, the installation space 22123 is configured as a channel that passes through the upper and lower surfaces of the main frame 2212, and the lower opening of the channel corresponds to the first opening 22124. The first scraper 241 is placed in the channel to press 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, Fig.40 As shown, the channel is configured as a rectangular parallelepiped structure that passes through the upper and lower sides of the main frame 2212 and is arranged in 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 rectangular parallelepiped 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., and this application does not impose any limitation on this.

[0140] In this embodiment, the first opening 22124 can form the redundant space on the upper and lower sides of the first scraper 241, so that the first scraper 241 can naturally adhere to the surface of the powder roller 2211 only by relying on its own gravity, thereby avoiding applying forced pressure to the powder roller 2211. For example, when large particles of powder that are difficult to remove are attached to the powder roller 2211, the first scraper 241 can be pushed by the large particles of powder and temporarily lifted from the installation space 22123, thereby avoiding surface damage of the powder roller 2211 caused by rigid contact.

[0141] In another embodiment, the redundant space can be formed on the front and rear sides and the upper and lower sides of the first scraper 241, that is, the first scraper 241 can have free movement space in the four directions of the upper, lower, left and right. This allows the first scraper 241 to be temporarily lifted or sideways when it contacts a foreign object with strong adhesion, and can be quickly reset by its own weight after the foreign object passes through. At the same time, the first scraper 241 is easy to install or remove from the installation space 22123, so as to facilitate the maintenance or replacement of the first scraper 241. In addition, this flexible avoidance method can reduce the hard friction between the first scraper 241 and the powder spreading roller 2211, avoid mechanical damage to the surface of the powder spreading roller 2211, and avoid the foreign object from blocking the powder spreading roller 2211. It should be understood that even if the foreign object is difficult to scrape off due to its strong adhesion and temporarily passes through the redundant space, it will contact the first scraper 241 again and again as the powder spreading roller 2211 rotates, thereby gradually becoming loose until it is scraped off by the first scraper 241.

[0142] See also Fig.42 , which is a schematic diagram showing the contact between the first blade portion and the powder spreading roller in one embodiment of the present application, such as Fig.42 As shown, the end of the first blade portion 2412 forms a contact surface 24121 so that the first scraper 241 scrapes the powder in surface contact. It should be understood that scraping the powder in the form of surface contact can increase the cleaning area of ​​the first scraper 241 on the powder spreading roller 2211 to ensure the cleaning effect, and on the other hand, can reduce the pressure of the first scraper 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 straight chamfer polished at the end of the first blade portion 2412.

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

[0144] In another embodiment, if Fig.37 and Fig.38 As shown, the scraper assembly 24 is configured to include two scrapers. In order to distinguish from the first scraper 241, Fig.37 and Fig.38The two scrapers included in the scraper assembly 24 are respectively referred to as the second scraper 242 and the third scraper 243. The second scraper 242 and the third scraper 243 will not be described in detail later. In this example, the second scraper 242 and the third scraper 243 are respectively located at the front and rear sides of the powder spreading roller 2211. Specifically, the second scraper 242 is located at the rear side of the powder spreading roller 2211, and is used to scrape off the powder in the forward rotation of the powder spreading roller 2211 during the return movement of the second base 221. The third scraper 243 is located at the front side of the powder spreading roller 2211, and is used to scrape off the powder in 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 a forward powder spreading operation, that is, the second base 221 is in the process of moving forward, the powder spreading roller 2211 rotates counterclockwise, at this time, the third scraper 243 can scrape off the powder remaining on the powder spreading roller 2211 and retain 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 a reverse powder spreading operation, that is, the second base 221 is in the process of moving back, the powder spreading roller 2211 rotates clockwise, at this time, the second scraper 242 can scrape off the powder remaining on the powder spreading roller 2211 and retain 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] See also Fig.43 , which is a schematic diagram of the structure of the third scraper in one embodiment of the present application, such as Fig.43 As shown, the side of the third scraper 243 is an irregular pentagon as a whole, and the third scraper 243 can be configured to include an integrally formed main body 2431 and a blade 2432. In one embodiment, the second scraper 242 and the third scraper 243 can be configured in the same manner, that is, Fig.38 As shown, the second scraper 242 includes a main body 2421 and a blade 2422. In order to distinguish from the first main body 2411 and the first blade 2412 included in the first scraper 241, the main body 2421 and the blade 2422 included in the second scraper 242 can be referred to as the second main body 2421 and the second blade 2422, and the main body 2431 and the blade 2432 included in the third scraper 243 can be referred to as the third main body 2431 and the third blade 2432. In this example, the second main body 2421 and the third main body 2431 can be used to respectively install the second scraper 242 and the third scraper 243 on the second base 221, and the second blade 2422 and the third blade 2432 can be used to respectively scrape away the residual powder on the powder spreading roller 2211.

[0147] See also Fig.44 Combined with Fig.38 ,in, Fig.44The schematic diagram of the second scraper and the third scraper in one embodiment of the present application is shown as follows: Fig.38 and Fig.44 As shown, the second scraper 242 and the third scraper 243 are perpendicular to the central axis O of the molding platform 1 with the powder spreading roller 2211. 1 In this example, the central axis O 1 The diameter of the cross section of the powder spreading roller 2211 is passed, and the second blade portion 2422 of the second scraper 242 and the third blade portion 2432 of the third scraper 243 symmetrically face and contact the surface of the powder spreading roller 2211 to scrape away the residual powder. Fig.44 As shown, the 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, this is not limited to the above, and the angle α can be adjusted according to actual production requirements.

[0148] In one embodiment, the second blade portion 2422 and the third blade portion 2432 scrape the powder in line contact. The line contact means that when scraping the powder, the ends of the second blade portion 2422 and the third blade portion 2432 are respectively attached to the surface of the powder roller 2211 in a straight line. In the example where the powder roller 2211 is configured as a cylinder, the straight line at the attachment point of the second blade portion 2422 and the powder roller 2211, or the third blade portion 2432 and the powder roller 2211 can appear to coincide with the generatrix of the cylinder. In this embodiment, scraping the powder in the form of line contact can increase the pressure of the second scraper 242 and the third scraper 243 on the powder roller 2211, making the powder easier to scrape off.

[0149] The following description is made by taking the third blade portion 2432 and the powder spreading roller 2211 in line contact to scrape off the powder as an example. Fig.45 , which is a schematic diagram showing that the third blade portion is in line contact with the powder spreading roller in one embodiment of the present application, such as Fig.45 As 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 formed between the end of the pentagonal cross section of the third scraper 243 and the circular cross section of the powder spreading roller 2211. Similarly, as Fig.44As shown, a contact point 24221 is formed between the second blade 2422 of the second scraper 242 and the circular cross section of the powder spreading roller 2211. For ease of description and distinction, the contact point 24221 between the second blade 2422 and the powder spreading roller 2211 is referred to as the second contact point 24221, and the contact point 24321 between the third blade 2432 and the powder spreading roller 2211 is referred to as the third contact point 24321.

[0150] In one embodiment, if Fig.44 As 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, about 270°, 275°, 280°, 285°, 290°, 295°, 300°, 305°, 310°, 315°, 320°, 325°, or 330°.

[0151] In one embodiment, the second scraper 242 and the third scraper 243 are arranged on the side support plate 2213 in a gravity-offset manner. The gravity-offset means that the gravity center of the second scraper 242 or the third scraper 243 deviates from its geometric center, so that the overall weight of the second scraper 242 or the third scraper 243 is offset toward the powder spreading roller 2211. In this embodiment, the second blade 2422 and the third blade 2432 are automatically attached to the surface of the powder spreading roller 2211 by the gravity-offset manner, so that the pressure distribution of the second blade 2422 and the third blade 2432 on the surface of the powder spreading roller 2211 is uniform, and at the same time, the impact force of the foreign matter on the second blade 2422 and the third blade 2432 can be reduced, and the probability of chipping can be reduced.

[0152] For example, the third scraper 243 is disposed on the side support plate 2213. Fig.46 Combined with Fig.37 and Fig.38 ,in, Fig.46 The schematic diagram of the split structure of the third scraper and the side support plate in one embodiment of the present application is shown as follows: Fig.46 As shown, the side support plate 2213 is provided with a second mounting portion 22131 on the basis of the first mounting portion for mounting the powder spreading roller 2211, and the third scraper 243 is mounted on the second mounting portion 22131 and tilted toward the powder spreading roller 2211 so that the third blade portion 2432 contacts the powder spreading roller 2211. In one example, the second mounting portion 22131 can be configured as a hole structure.

[0153] In one embodiment, if Fig.43 and Fig.46As shown, the side end surface of the third scraper 243 is provided with an axle connection member 2433 rotatably connected to the second mounting portion 22131, and the center of gravity of the third scraper 243 is located in a region above the axis of the axle connection member 2433 so that the third scraper 243 is tilted toward the powder spreading roller 2211 by gravity. In one implementation, the weight of the third main body portion 2431 is greater than that of the third blade portion 2432. Fig.43 As shown, the shaft connecting member 2433 is configured on the third blade portion 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. Fig.46 Rotate in the direction of the arrow shown in the middle arc. Fig.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. Fig.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 may also be configured to include more than two scrapers. For example, the scraper assembly 24 may also be configured to include three scrapers, and the three scrapers may be configured as a first scraper 241, a second scraper 242, and a third scraper 243, respectively. The first scraper 241 is disposed on the powder spreading roller 2211 perpendicular to the central axis O of the molding platform 1. 1 The second scraper 242 and the third scraper 243 are arranged along the central axis O 1 Symmetrical configuration, but not limited to this, can be determined according to actual production needs.

[0156] In one embodiment, if Figure 3 Shown and combined Figure 2The 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 receiving component 21 can be used to receive powder. In this embodiment, the powder spreading system 2 also includes a feeding component (not shown) for supplying powder to the first receiving component 21. In one example, the feeding component can be configured to include a storage bin, a screw feeder, and a vibration plate, the storage bin is used to store a certain amount of powder, the screw feeder can convey the powder from the storage bin to the first receiving component 21 in a spiral manner to achieve the supply of powder, and the vibration plate can keep the powder in a loose state during supply by vibration, thereby avoiding agglomeration of the powder.

[0158] In one embodiment, the powder spreading system 2 further includes the aforementioned regulating supply component, which is used to regulate the amount of powder supplied to the first receiving component 21 according to the received instruction. In some examples, the amount of powder refers to the weight or volume of powder supplied to the first receiving component 21. In some examples, the regulating supply component can adjust the amount of powder supplied or the number of powder supplies based on the printing requirements of each printing layer, such as layer thickness or printing speed, to achieve the regulation of the amount of powder supplied to the first receiving component 21.

[0159] In one example, the powder supply regulating component can be configured to include a weighing sensor to monitor the actual powder supply mass supplied to the first receiving component 21, and generate a powder supply signal to transmit 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 outputs the control instruction to the regulating supply component, the regulating supply component can adjust the powder supply amount in real time according to the control instruction, for example, by adjusting the rotation speed of the screw feeder. However, this is not limited to this, as long as the powder supply amount can be adjusted.

[0160] As mentioned above, during the powder spreading process, the height of the powder falling will affect the molding quality. For example, in the related art, the powder is directly dropped from the first receiving component to the molding platform, and the powder falling height can reach 120mm, which will form dust in the molding room, thereby affecting the molding quality. In view of this, in one embodiment, if Figure 3As shown, the powder spreading device 22 also includes a second material receiving component 222, and the second material receiving component 222 is used for low-position powder dropping. Specifically, the second material receiving component 222 is used to dock with the first material receiving component 21 when following the movement of the powder spreading roller 2211 toward the first area 12 to receive and cache the powder from the first material receiving component 21, and to release the cached powder at a low position by the powder spreading roller 2211 when following the movement of the powder spreading roller 2211 toward the second area 13. The second material receiving component capable of low-position powder dropping provided in this embodiment can reduce the powder dropping height to less than 10 mm, thereby effectively avoiding dust.

[0161] In one embodiment, the powder falling height of the powder spreading device 22 is greater than the accumulation height of the powder falling to the molding platform 1. The powder falling height refers to the vertical distance of the powder falling freely from the second material receiving component 222 to the molding platform 1, which is equal to the vertical distance from the second material receiving component 222 to the molding platform 1. It should be understood that if the powder falling height is less than or equal to the accumulation height, the powder outlet of the second material receiving component 222 may be blocked by the accumulated powder, thereby affecting the further falling of the powder in the second material receiving component 222, thereby causing interruption of powder spreading or uneven powder spreading.

[0162] In one embodiment, the powder falling height of the powder spreading device 22 is less than or equal to the height of the powder spreading roller 2211. The height of the powder spreading roller 2211 refers to the height of the highest point of the powder spreading roller 2211 from the molding platform 1. In the example where the powder spreading roller 2211 is attached to the upper surface of the molding platform, the height of the powder spreading roller 2211 can correspond to the diameter height of the powder spreading roller 2211 perpendicular to the molding platform. It should be understood that if the powder falling height is greater than the height of the powder spreading roller 2211, it will hinder the effect of the powder spreading device 22 in avoiding dust. In actual application, it is necessary to balance the powder falling height, the accumulation height of the powder, and the height of the powder spreading roller, so as to effectively avoid dust while ensuring the continuity of powder falling.

[0163] In one embodiment, if Figure 3 As shown, the second material receiving assembly 222 is disposed on the second side of the second base 221. Fig.23 , which is a schematic diagram of the structure of the second material receiving component in one embodiment of the present application. Fig.23 As shown, the second material receiving assembly 222 includes a connecting member 223 and a second material receiving hopper 224. The connecting member 223 has a fixing section 2231 fixed to the second base 221 and a connecting section 2232 extending toward the second side from the second base 221. The second material receiving hopper 224 is arranged on the connecting section 2232 to hang on the second side of the second base 221.

[0164] The hanging means that the upper side of the second receiving hopper 224 is fixed to the connecting section 2232, so that the lower side of the second receiving hopper 224 can hang freely. In one example, the connecting member 223 is configured as a connecting rod, the fixing section 2231 on the first side is fixed to the second base 221 in a screw connection manner, and the connecting section 2232 on the second side is connected to the second receiving hopper 224. In one example, Fig.23 As shown, there are two connecting members 223 , which are respectively connected to the opposite ends of the second receiving hopper 224 .

[0165] See also Fig.24 and Fig.25 , respectively, are schematic diagrams showing the structure of the second receiving hopper in different embodiments of the present application, such as Fig.24 and Fig.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 dropping port 2243. The second hopper body 2241 is used to cache powder, the second material receiving port 2242 is used to dock with the first material receiving assembly 21, and the second material dropping port 2243 is used to release the cached powder at a low position onto the moving path of the powder spreading roller 2211. Fig.24 and Fig.25 In the example shown, the powder material can be supplied to the first material receiving component 21 by the material supply component, and fall into the second bucket body 2241 through the second material receiving port 2242 , and finally fall onto the forming platform 1 from the second material receiving port 2242 .

[0166] In one embodiment, if Fig.24 and Fig.25 As shown, the second bucket body 2241 includes a buffer portion 22412 and a guide portion 22413, wherein the buffer portion 22412 is connected to the second material receiving port 2242, and the guide portion 22413 is formed in accordance with the buffer portion 22412 and connected to the second material dropping port 2243, and the guide portion 22413 is inclined toward the powder spreading roller 2211 to guide the powder dropping. Fig.24 and Fig.25 As shown, the buffer portion 22412 is the vertical portion of the second bucket body 2241, and the guide portion 22413 is the inclined portion of the second bucket body 2241. The connection between the buffer portion 22412 and the guide portion 22413 forms a corner on the second bucket body 2241, and the corner can provide a buffering effect for the powder cached in the buffer portion 22412 to fall. In this example, the feeding assembly supplies the powder to the first receiving assembly 21, and the powder enters the buffer portion 22412 of the second bucket body 2241 through the second receiving port 2242. The powder cached in the buffer portion 22412 flows to the inclined guide portion 22413 due to gravity, and falls through the second drop port 2243. In one example, the inner wall of the second bucket body 2241 can be smoothed to reduce the adhesion of the powder.

[0167] In one embodiment, if Fig.25 As shown, the second receiving hopper 224 further includes a door assembly 2246, which is disposed on the second hopper body 2241 to open or close the second material drop opening 2243. Fig.26 Combined with Fig.25 ,in, Fig.26 The schematic diagram of the state of the second receiving hopper in the reverse powder spreading operation in one embodiment of the present application is shown, wherein the second receiving hopper 224 includes a door assembly 2246. When the powder spreading device 22 performs the reverse powder spreading operation, that is, when the second receiving hopper 224 moves toward the first area 12 and docks with the first receiving assembly 21, the door assembly 2246 is in a closed state as shown in 25, and the powder can be cached in the second receiving hopper 224. When the powder spreading device 22 is about to perform the forward powder spreading operation, that is, when the second receiving hopper 224 moves toward the second area 13, the door assembly 2246 is in a closed state as shown in 25. Fig.26 In the open state shown, the powder can fall toward the powder spreading roller 2211 through the guide portion 22413, thereby further reducing the powder falling height to increase the effect of avoiding dust.

[0168] See also Fig. 27 Combined with Fig.25 ,in, Fig. 27 The structure diagram of the door assembly in one embodiment of the present application is shown as follows: Fig.25 and Fig. 27 As shown, 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 blanking opening 2243. One side of the door body 2248 is rotatably connected to the mounting assembly 2247 and forms an opening angle with the second blanking opening 2243 on the other side. The opening angle refers to the opening of the door body 2248 relative to the second blanking opening 2243. For example, when the door body 2248 is Fig.25 The closed state shown transitions to Fig.26 In the open state shown, the opening angle increases gradually.

[0169] In one embodiment, the mounting assembly 2247 can be configured as a hinge, one end of which can be connected to the second bucket body 2241 on the upper side of the second drop port 2243, for example, by bolts, 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 to achieve the opening and closing of the second drop port 2243.

[0170] In one embodiment, if Fig. 27 As shown, the door body 2248 includes a main body portion 22481 and a closing portion 22482 formed by bending at two sides of the main body portion 22481 . Fig.25As shown, the closing portion 22482 can be fitted with both sides of the second bucket body 2241 so that the door assembly 2246 can completely close the second drop opening 2243 when it is closed, thereby preventing the powder from leaking from the joint between the door body 2248 and the second bucket body 2241. In some examples, a buffer may be further configured at the closing portion 22482 to prevent the door body 2248 from colliding with the second bucket body 2241 when the door assembly 2246 is closed. The buffer may be configured as a rubber strip or a silicone pad, for example.

[0171] In one embodiment, if Fig.23 As shown, the second receiving hopper 224 is rotatably disposed on the connecting section 2232 . In some examples, the second receiving hopper 224 can rotate at 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 angle between the plane where the second receiving port 2242 is located and the plane where the two connecting sections 2232 are located. The rotation axis can be the shaft assembly 22411 described in the subsequent embodiments.

[0172] In one embodiment, if Fig.24 and Fig.25 As shown, the second hopper body 2241 is provided with an axis assembly 22411 installed on the connecting section 2232, and the axis assembly 22411 is supported on the connecting section 2232 so that the second receiving port 2242 of the second receiving hopper 224 is suspended in an inclined posture with the second side higher than the first side, and the suspended state of the second receiving hopper 224 is as shown in FIG. Fig.26 The hanging in an inclined posture refers to the natural state of the second receiving hopper 224 when it is not subjected to external force, for example, the state when the second receiving hopper 224 and the first receiving component 21 are not in contact.

[0173] In one embodiment, the height position of the first side of the second receiving port 2242 is lower than the first receiving assembly 21 to allow the second receiving hopper 224 to pass through the first receiving assembly 21. Figures 28 to 30 Combined with Fig.26 ,in, 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 Fig.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 and the first material receiving assembly 21 move relatively away from each other, and the second material receiving hopper 224 is in a suspended state.

[0174] Thereafter, as Fig.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 Fig.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, and thus the second material receiving hopper 224 gradually rotates from the suspended state to Fig.29 the docking state shown. In the docking state shown in Fig.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 Fig.30 and presents the suspended state shown in Fig.26 .

[0176] In an embodiment, please refer to Fig.31 and combine with Fig.23 . Fig.31 Shown is a schematic diagram of the connecting member in an embodiment of the present application. As Fig.23 and Fig.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 so that the shaft assembly 22411 can enter or leave the groove 22321. The shaft assembly 22411, as the rotating shaft of the second receiving hopper 224, can drive the second receiving hopper 224 to rotate in the groove 22321. In one example, the groove 22321 is generally "U"-shaped, 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 "U"-shaped opening, thereby facilitating cleaning or replacement of the second receiving hopper 224.

[0177] In one embodiment, if Fig.24 and Fig.25 As shown, the second receiving hopper 224 also includes a blocking portion 2244 protrudingly arranged on the second side of the second receiving port 2242, and the blocking portion 2244 is blocked by the first receiving component 21 when the second receiving hopper 224 passes through the first receiving component 21 and moves toward the first area 12, so as to prompt the second receiving hopper 224 to rotate toward the first receiving component 21 to dock with the first receiving component 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, which can be against the second side of the first receiving component 21 to block the first receiving component 21. In some implementations, it can be integrally formed with the side wall of the second hopper body 2241, or it can be fixed to the side wall of the second hopper body 2241 by welding or the like.

[0178] Please combine Figures 28 to 30 In the process that the second receiving hopper 224 follows the powder spreading roller 2211 to move toward the first area 12, the blocking portion 2244 gradually abuts against the second side of the first receiving component 21, and when the two are just in contact, a Fig.28 Then, due to the movement of the second receiving hopper 224 toward the first area, the second side of the first receiving component 21 applies a thrust to the blocking portion 2244, which causes the second receiving hopper 224 to rotate clockwise in the groove 22321 with the shaft component 22411 as the axis, so that the angle between the bottom of the first receiving component 21 and the top of the second receiving hopper 224 gradually decreases, thereby presenting Fig.29 The status shown. Fig.30 As shown, when the blocking portion 2244 is in contact with the second side of the first material receiving component 21, the second material receiving hopper 224 and the first material receiving component 21 can be docked.

[0179] In one embodiment, if Fig.24 and Fig.25 As shown, the second receiving hopper 224 further includes a second stop portion 2245 located at a first side of the second receiving opening 2242. Figures 28 to 30As shown, the first material receiving component 21 is provided with a first stopper 2133 corresponding to the second stopper 2245, and the first stopper 2133 cooperates with the first stopper 2133 when the second material receiving hopper 224 docks with the first material receiving component 21 to prevent the second material receiving hopper 224 from over-rotating. It should be noted that the first stopper 2133 can be further provided on the docking portion 213 of the first material receiving component 21, wherein 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 continued rotation of the second receiving hopper 224 after the first receiving component 21 is docked with the second receiving hopper 224, and the continued rotation will cause the first receiving component 21 and the second receiving hopper 224 to deviate from the docking state. For example, if the first stop portion and the second stop portion are not provided, when the first receiving component 21 and the second receiving hopper 224 are completely docked and present Fig.30 In the state shown, the second material receiving hopper 224 will still have a tendency to move toward the first area 12 driven by the powder spreading roller 2211. Under this tendency, the second material receiving hopper 224 will continue to rotate clockwise in the groove 22321 with the shaft assembly 22411 as the axis.

[0181] In one embodiment, the first stop portion 2133 and the second stop portion 2245 are both configured as a plate-like structure extending horizontally from the corresponding material receiving assembly. Fig.30 In the docking state shown, the first stop portion 2133 and the second stop portion 2245 fit together to serve as a limit device to prevent the second receiving hopper 224 from continuously rotating clockwise.

[0182] In e.g. Figures 28 to 30 In the embodiment where the second receiving hopper 224 is rotatable and includes a door body 2248, the door body 2248 gradually closes the opening angle to receive the material by its own weight when the second receiving hopper 224 rotates to connect with the first receiving assembly 21, and forms the opening angle again to drop the material by the rotational movement of the second receiving hopper 224 when it leaves the first receiving assembly 21 and moves toward the second area 13. That is to say, the opening or closing of the door body 2248 relative to the second dropping port 2243 is driven by the own weight of the door body 2248, such as Fig.26 As shown, the second receiving hopper 224 is suspended in a natural state due to its center of gravity. At this time, the door body 2248 naturally droops due to its own gravity, so that it is in an open state.

[0183] It should be understood that as the second receiving hopper 224 rotates clockwise, the door body 2248 will first maintain its naturally drooping state due to inertia, and then cover the second drop opening 2243 in accordance with 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 by the driving mechanism.

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

[0185] The following combination Fig.26 ,as well as Figures 28 to 30 The opening or closing process of the door body 2248 is described in detail: when the powder spreading device 22 completes the reverse powder spreading operation, that is, when the second receiving hopper 224 moves toward the first area 12, the second receiving hopper 224 is opened. Fig.26 The hanging state shown gradually changes to Fig.30 In the docking state shown in the figure, during this process, the opening angle of the door body 2248 gradually decreases until the second drop 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 assembly 21 and be buffered 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 toward the second area 13, the second receiving hopper 224 is Fig.30 The docking state shown gradually changes to Fig.26 The hanging state shown in the figure, during this process, the opening angle of the door body 2248 gradually increases until the second drop port 2243 is opened to present the open state of the door assembly 2246. At this time, the powder buffered in the second bucket body 2241 can fall toward the powder spreading roller 2211 at a low position to facilitate the powder spreading roller 2211 to spread the powder in the molding area 11.

[0186] See also Fig.32 and Fig.33 ,in, Fig.32 It is a schematic diagram of a first material receiving component in one embodiment of the present application. Fig.33 The cross-sectional view of the second receiving hopper docking with the first receiving assembly in one embodiment of the present application is shown. Fig.32 and Fig.33As shown, the first material receiving assembly 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 dropping port 2122. In this example, the first material receiving port 2121 and the first material dropping port 2122 are respectively located on the upper side and the lower side of the first hopper body 212, and the first material receiving port 2121 is used to connect the aforementioned material supply assembly to supply powder to the first material receiving assembly 21, and the first material dropping port 2122 is connected to the second material receiving port 2242 when the second material receiving assembly 222 is docked with the first material receiving assembly 21 so that the powder falls from the second material dropping port 2243. In one example, the first hopper body 212 and the docking portion 213 can be connected in an integral molding manner or a fixed connection manner. In one example, the inner wall of the first hopper body 212 can be smoothed to reduce the adhesion of powder. In one example, the width of the first bucket body 212 may be smaller than the width of the second bucket body 2241 so that the powder in the first material receiving component 21 can smoothly enter the second material receiving component 222 .

[0187] like Fig.32 and Fig.33 As shown, the docking portion 213 extends downwardly corresponding to the first material drop opening 2122, and enters the second material receiving opening 2242 to guide the powder material into the second material receiving assembly 222 when the second material receiving hopper 224 docks with the first material receiving assembly 21. It should be understood that when the second material receiving hopper 224 docks with the first material receiving assembly 21, the docking portion 213 can extend into the second material receiving opening 2242 to prevent the powder material from leaking from the joint between the first material receiving assembly 21 and the second material receiving assembly 222.

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

[0189] See also Fig.34 , shown as this application Fig.33 The local enlarged schematic diagram of A in the embodiment shown. Fig.34As shown, the docking portion 213 includes a second baffle 2132 located on the second side of the first drop port 2122, and the second baffle 2132 is used to block the blocking portion 2244, and the blocking portion 2244 is impacted by the second baffle 2132 when the second receiving hopper 224 rotates to shake off the powder remaining on the hopper wall of the first receiving hopper 211.

[0190] Specifically, when performing the reverse powder spreading operation, the first material receiving component 21 may be located at the initial position, for example, and the second material receiving hopper 224, driven by the powder spreading device 22, follows the powder spreading roller 2211 to complete a forward powder spreading operation and is located at the return position. At this time, the second material receiving hopper 224 is in Fig. 27 In the suspended state shown in the figure, as the powder spreading device 22 drives the second receiving hopper 224 to move toward the initial position to perform the reverse powder spreading operation, the first receiving component 21 and the second receiving hopper 224 gradually complete the Figures 28 to 30 The docking process is shown.

[0191] When the two are docked, the blocking portion 2244 and the second baffle 2132 fit each other. As mentioned above, the second receiving hopper 224 still has a tendency to move toward the first area 12 under the drive of the powder spreading roller 2211. Under this tendency, the blocking portion 2244 blocks the continued translation of the second receiving hopper 224 on the one hand, and causes it to rotate with the shaft assembly 22411 as the axis. On the other hand, the blocking portion 2244 will collide with the second baffle 2132, thereby shaking off the powder remaining on the hopper wall of the first receiving hopper 211. When the first receiving assembly 21 supplies powder for each powder spreading operation, it can ensure that the powder falls completely, which can prevent the first receiving assembly 21 from being blocked by the residual powder and prevent the waste of powder.

[0192] In one embodiment, if Fig.34 As shown, the docking portion 213 includes a first baffle 2131 located on the first side of the first drop port 2122, and the first baffle 2131 is used to collide with the second material receiving hopper 224 rotating by its own weight when the second material receiving hopper 224 moves toward the second area 13 to shake off the powder remaining on the hopper wall of the second material receiving hopper 224.

[0193] Specifically, when the second receiving hopper 224 moves toward the second area 13 to perform the forward powder spreading operation, the second receiving hopper 224 is Fig.30 The docking status shown changes to Fig.26 In the suspended state shown, the first baffle 2131 will collide with the bucket wall of the first side of the second receiving hopper 224, thereby shaking off the powder remaining on the bucket wall of the second receiving hopper 224. In one example, the first baffle 2131 or the second baffle 2132 can be configured as a collision-resistant material such as hardened steel.

[0194] In summary, the 3D printing device and powder spreading system disclosed in the present application realize powder spreading operation by a powder spreading device that can move back and forth between the first area and the second area of ​​the molding 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 molding chamber, the first material receiving component and the second material receiving component can be docked when the powder spreading roller moves toward the first area, so that the powder material is cached in the second material receiving component. In addition, when the powder spreading roller moves toward 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 material at a low position, thereby avoiding dust and ensuring the molding environment in the molding chamber. By arranging a door component that can open or close the second material drop port at the second material receiving hopper of the second material receiving component, the powder material can be cached in the second material receiving hopper and then fall, thereby further reducing the powder drop height. By arranging a second baffle or the 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 to prevent the powder from accumulating in the material receiving hopper and falling on the powder layer on which the powder spreading operation has been completed, thereby ensuring the powder spreading effect.

[0195] Furthermore, by providing a powder spreading roller in the powder spreading device that can be driven to rotate when following the horizontal movement of the base, the powder can be spread in the molding area. By providing 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 being left behind. In addition, the design of the scraper can also prevent powder with a certain hardness from being embedded therein, thereby avoiding scratches on the powder spreading roller.

[0196] When the scraper assembly is configured to include a scraper, the scraper is configured to press on the powder spreading roller by its own weight and redundant space for the scraper to move is provided in the installation space, so that the scraper can be temporarily lifted or moved sideways when it contacts foreign matter with strong adhesion, and can be quickly reset by its own weight after the foreign matter passes, which is also convenient for 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 matter from blocking the powder spreading roller.

[0197] When the scraper assembly is configured to include two scrapers, the two scrapers are arranged on the base in a manner with the center of gravity offset, and the torque generated by the dead weight of the two scrapers is used to make the blade portion automatically adhere to the surface of the powder spreading roller, so that the pressure of the blade portion on the surface of the powder spreading roller is evenly distributed. At the same time, the impact force of foreign matter on the blade portion can be reduced, reducing the probability of blade chipping.

[0198] In addition, by providing a powder spreading device that can move back and forth between the first area and the second area of ​​the molding platform in the powder spreading system, powder spreading operations in the flattening stage and the printing stage can be realized. By providing a powder return detection mechanism on the upper side of the first powder return trough, it is possible to detect the powder surface distance of the first powder return trough when the powder spreading device completes a back and forth movement, thereby realizing the detection of whether the flattening stage is completed, ensuring that the powder layer in the molding area has been flattened 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, it is possible to prevent the high temperature environment in the molding chamber from affecting the normal operation of the powder return detection mechanism. By providing a light-transmitting protective plate in the optical channel of the powder return detection mechanism, a physical barrier can be provided to prevent the powder from affecting the powder return detection mechanism from receiving the reflected light signal. By guiding the airflow from the cleaning mechanism to the bottom of the light-transmitting protective plate to clean the gas guiding structure of the light-transmitting protective plate, the powder or oil mist on the light-transmitting protective plate can be cleaned, thereby further ensuring the normal operation of the powder return detection mechanism.

[0199] The above embodiments are merely illustrative of the inventive essence of the present application and the beneficial effects obtained, and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the principles and scope of the present application. Therefore, all equivalent modifications or changes achieved by a person with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present application shall 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 comprises a molding platform and a molding chamber located on the molding platform, wherein the molding platform has a molding area and a first area and a second area located on opposite sides of the molding area, and the powder spreading system comprises: A first material receiving assembly is arranged in the molding chamber and suspended in the first area; A powder spreading device is arranged at the lower side of the first material receiving component, and is used for being driven to move back and forth between the first area and the second area to perform powder spreading operation on the molding platform, wherein the powder spreading device comprises a powder spreading roller for spreading powder on the molding area and a second material receiving component for dropping powder at a low position, 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 buffer it when following the powder spreading roller to move toward the first area, and to release the buffered powder at a low position by the powder spreading roller when following the powder spreading roller to move toward 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 the base and a connecting section extending from the base toward the second side, the second material receiving hopper is rotatably arranged on the connecting section and hangs on the second side of the base, the second material receiving hopper includes a second hopper body for caching powder, a second material receiving port for docking with the first material receiving component, a blocking portion protrudingly arranged on the second side of the second material receiving port, and a second material dropping port for dropping the cached powder at a low position to the moving path of the powder spreading roller, the blocking portion is blocked by the first material receiving component when the second material receiving hopper passes through the first material receiving component and moves toward the first area to prompt the second material receiving hopper to rotate toward the first material receiving component to dock with the first material receiving component.

2. The powder spreading system of the 3D printing device according to claim 1, characterized in that: The powder falling height of the powder spreading device is greater than the accumulation 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 falling 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 molding 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 assembly is arranged on a second side of the base.

5. The powder spreading system of the 3D printing device according to claim 1, characterized in that: The second receiving hopper can rotate at an angle of 10° to 60°.

6. The powder spreading system of the 3D printing device according to claim 1, characterized in that: The second hopper body is provided with an axis assembly installed on the connecting section, and the axis assembly is supported on the connecting section so that the second receiving port of the second material receiving hopper is suspended in an inclined posture with the second side higher than the first side; wherein the height position of the first side of the second material receiving port is lower than the first material receiving assembly to allow the second material receiving hopper to pass through the first material receiving assembly.

7. The powder spreading system of the 3D printing device according to claim 6, characterized in that: The connecting section is provided with a groove for accommodating the shaft assembly, and the groove has an opening so that the shaft assembly 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 assembly includes a first material receiving hopper, and the first material receiving hopper includes: The first bucket body has a first material receiving opening and a first material dropping opening; The docking portion is arranged to extend downwardly corresponding to the first material drop opening, and when the second material receiving hopper docks with the first material receiving component, it enters the second material receiving opening to guide the powder material 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 portion includes a second baffle located at the second side of the first drop port, the second baffle being used to block the blocking portion and being impacted by the second baffle when the second receiving hopper rotates to shake off powder remaining on the hopper wall of the first receiving hopper.

10. The powder spreading system of the 3D printing device according to claim 8, characterized in that: The docking portion includes a first baffle located on the first side of the first drop port, and the first baffle is used to collide with the second receiving hopper rotating by its own weight when the second receiving hopper moves toward the second area to shake off the powder remaining on the hopper wall of the second receiving hopper.

11. The powder spreading system of the 3D printing device according to claim 8, characterized in that: The second material receiving hopper also includes a second stop portion located on the first side of the second material receiving port, and the docking portion is provided with a first stop portion corresponding to the second stop portion, and the first stop portion cooperates with the first stop portion when the second material receiving hopper docks with the first material receiving assembly to prevent the second material receiving hopper from over-rotating.

12. The powder spreading system of the 3D printing device according to claim 1, characterized in that: The second bucket body includes a buffer portion connected to the second material receiving port and a guide portion formed in accordance with the buffer portion and connected to the second material dropping port, and the guide portion is inclined toward the powder spreading roller to guide the powder dropping.

13. The powder spreading system of the 3D printing device according to claim 1, characterized in that: The second receiving hopper also includes a door assembly arranged on the second hopper body to open or close the second material drop opening.

14. The powder spreading system of the 3D printing device according to claim 13, characterized in that: The door assembly comprises: A mounting assembly, arranged on the upper side of the second blanking opening; The door body has one side rotatably connected to the mounting assembly and forms an opening angle with the second material drop opening on the other side, and gradually closes the opening angle to receive materials by relying on its own weight when the second material receiving hopper rotates to dock with the first material receiving assembly, and forms the opening angle again to drop materials through the rotational movement of the second material receiving hopper when it leaves the first material receiving assembly and moves toward the second area.

15. The powder spreading system of the 3D printing device according to claim 14, characterized in that: The door body includes a main body portion and a closing portion formed by bending at two sides of the main body portion.

16. The powder spreading system of the 3D printing device according to claim 14, characterized in that: A counterweight is provided at one end of the door body close to the molding area.

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

18. The powder spreading system of the 3D printing device according to claim 1, characterized in that: The powder spreading system also includes a material supply adjustment component for adjusting the amount of powder supplied to the first material receiving component according to the received instructions.

19. A 3D printing device, characterized in that: include: A molding platform, which has a molding area and a first area and a second area located on opposite sides of the molding area, a component mechanism is provided corresponding to the molding area, and the component mechanism is used to move layer by layer in a vertical direction to attach a 3D component that is molded layer by layer by irradiating the molding area with an optical system; The powder spreading system according to any one of claims 1 to 18, used for spreading powder in the forming area; An optical system, used for emitting a light beam to irradiate the powder in the molding area; A control device 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 molding area during a printing operation, control the optical system to irradiate the powder in the molding area, and control the component mechanism to move vertically during a printing operation so as to attach the 3D component formed layer by layer to the component mechanism.

20. The 3D printing device according to claim 19, characterized in that: The 3D printing device is a selective laser sintering 3D printer.

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