3D printing equipment and its powder return mechanism

Abstract

This application discloses a powder return mechanism for a 3D printing equipment. The 3D printing equipment includes a molding chamber and a powder spreading device disposed within the molding chamber. The powder return mechanism includes: a first powder return trough and a second powder return trough, respectively disposed on opposite sides of the bottom surface of the molding chamber for collecting excess powder during the reciprocating powder spreading process of the powder spreading device; a first recovery chamber and a second recovery chamber, respectively disposed on the lower side of the molding chamber for collecting powder from the first powder return trough and the second powder return trough; a first powder return pipe and a second powder return pipe, the first powder return pipe connecting the first powder return trough and the first recovery chamber, and the second powder return pipe connecting the second powder return trough and the second recovery chamber; wherein at least one air passage is connected between the first powder return pipe and the second powder return pipe. By establishing an air passage connection between the first powder return pipe and the second powder return pipe, this application allows the air pressure in the recovery chamber to be released, thereby preventing powder from clogging the first powder return pipe or the second powder return pipe.

Description

Technical Field

[0001] This application relates to the field of 3D printing technology, and in particular to a 3D printing device and its powder return mechanism. Background Technology

[0002] With the rapid development of industrial technology, various 3D printing technologies using powder materials as raw materials are emerging, such as Selective Laser Melting (SLM), Selective Laser Sintering (SLS), Direct Laser Metal Deposition (DLMD), Electron Beam Melting (EBM), and Selective Heat Sintering (SHS).

[0003] Taking SLM-type 3D printing equipment as an example, in existing SLM-type 3D printing equipment, when the powder spreading device performs the powder spreading operation, excess powder is recovered into the powder recovery chamber through the powder return pipe. However, in actual use, powder falling solely under gravity may adhere to the pipe wall, or when a large amount of powder enters the pipe, the air pressure in the powder recovery chamber connected to the pipe may hinder the powder's fall, causing powder to clog the pipe and thus affecting printing efficiency and print quality.

[0004] Therefore, how to design a powder recovery mechanism that can eliminate the problem of blockage in the powder recovery pipeline when recovering excess powder is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of the shortcomings of the above-mentioned related technologies, the purpose of this application is to provide a 3D printing device and its powder return mechanism to solve the technical problem of powder recycling causing blockage of the powder return pipeline in the related technologies.

[0006] To achieve the above and other related objectives, a first aspect of this application provides a powder return mechanism for a 3D printing device. The 3D printing device includes a molding chamber and a powder spreading device disposed within the molding chamber. The powder return mechanism includes: a first powder return trough and a second powder return trough, respectively disposed on opposite sides of the bottom surface of the molding chamber for collecting excess powder during the reciprocating powder spreading by the powder spreading device; a first recovery chamber and a second recovery chamber, respectively disposed on the lower side of the molding chamber for collecting powder from the first powder return trough and the second powder return trough; a first powder return pipe and a second powder return pipe, the first powder return pipe connecting the first powder return trough and the first recovery chamber, and the second powder return pipe connecting the second powder return trough and the second recovery chamber; wherein at least one air passage is connected between the first powder return pipe and the second powder return pipe.

[0007] A second aspect of this application provides a 3D printing device, comprising: a forming platform having a forming chamber thereon, the forming platform having a forming hopper, a component platform and a Z-axis drive mechanism disposed within the forming hopper, the component platform being used to attach a 3D component formed layer by layer by an optical system, the Z-axis drive mechanism being connected to the component platform and being controlled to move vertically to adjust the distance between the component platform and the printing reference surface; a powder spreading device disposed within the forming chamber for spreading powder within the forming hopper; a powder return mechanism as described in the first aspect of this application for recovering excess powder from the powder spreading device during powder spreading; an optical system for emitting a light beam to irradiate the powder within the forming hopper; and a control device connected to the optical system, the Z-axis drive mechanism, and the powder spreading device for controlling the powder spreading device to spread powder into the forming hopper during a printing operation, controlling the optical system to irradiate the powder within the forming hopper, and controlling the Z-axis drive mechanism to move vertically during a printing operation to attach a solidified layer of a stacked pattern on the component platform to obtain a corresponding 3D component.

[0008] In summary, the 3D printing equipment and its powder return mechanism provided in this application achieve airflow communication between the first powder return pipe connecting the first powder return tank and the first recovery chamber and the second powder return pipe connecting the second powder return tank and the second recovery chamber by connecting at least one air passage pipe. This allows the airflow in the first powder return pipe or the second powder return pipe to flow through the air passage pipe when the air pressure in the recovery chamber obstructs the powder from falling into the first or second powder return pipe. This releases the air pressure in the recovery chamber and prevents the powder from clogging the first or second powder return pipe. Attached Figure Description

[0009] The specific features involved in this application are shown in the appended claims. A better understanding of the features and advantages of the invention can be achieved by referring to the exemplary embodiments and accompanying drawings described in detail below. A brief description of the drawings is as follows:

[0010] Figure 1 The diagram shown is a three-dimensional structural schematic of the powder return mechanism and the molding chamber of the 3D printing equipment connected thereto in one embodiment of this application, viewed from one perspective.

[0011] Figure 2 The diagram shown is a three-dimensional structural schematic of the powder return mechanism in one embodiment of this application from another perspective.

[0012] Figure 3 The diagram shown is a three-dimensional structural schematic of the powder return pipe and gas pipeline in one embodiment of this application from a single perspective. Detailed Implementation

[0013] The following specific embodiments illustrate the implementation of this application. Those skilled in the art can easily understand the advantages and technical effects of this application from the content disclosed in this specification. In the following description, some embodiments may be referenced to the accompanying drawings. It should be understood that other embodiments not shown in the drawings may also be used, and changes in specific structures, parts or mechanisms, components, and operations may be made without departing from the spirit and scope of this application. The following detailed description should not be considered limiting, and the scope of the embodiments of this application is limited only by the claims published in this application. The terminology used herein is for describing particular embodiments only and is not intended to limit this application.

[0014] It should be understood that although the terms first, second, or third, etc., may be used herein to describe various elements or parameters in some embodiments, these elements or parameters should not be limited by these terms. These terms are used only to distinguish one element or parameter from another, and not to define the order, priority, or importance of multiple elements. For example, a first connection portion may be referred to as a second connection portion, and similarly, a second connection portion may be referred to as a first connection portion, without departing from the scope of the various described embodiments.

[0015] Furthermore, as used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context indicates otherwise. It should be further understood that the terms “comprising,” “including,” and “including” indicate the presence of the stated features, steps, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. For example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices. Additionally, the term “and / or,” which may be used hereinafter, describes the relationship between related objects, indicating that three relationships may exist; for example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, the character “ / ”, unless otherwise specified, generally indicates that the preceding and following related objects have an “and / or” relationship. Additionally, in the description of embodiments of this application, “multiple” refers to two or more. Furthermore, the terms “or” and “and / or” as used herein are interpreted as inclusive, or mean either one or any combination thereof. Exceptions to this definition only arise when a combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0016] 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 "on" another element, the element may be directly on or directly extending onto the other element, or intermediate elements may be present. Conversely, when an element is referred to as being "directly on" another element or "directly extending onto" another element, no intermediate elements are present. It will also be understood that when an element is referred to as being "connected" or "attached" to another element, it may be directly connected or coupled to the other element, or intermediate elements may be present. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, no intermediate elements are present. Furthermore, the term "coupled" generally means physical, mechanical, magnetic, and / or electrical coupling or connection, and in the absence of specific contrasting language, the presence of intermediate elements between coupled or associated items is not excluded.

[0017] Relative terms such as “below,” “above,” “upper,” “lower,” “horizontal,” or “vertical” may be used herein to describe the relationship between one element, layer, or region and another element, layer, or region illustrated in the figures. It will be understood that these terms are intended to cover different device orientations other than those depicted in the figures. In this application, “vertical,” “horizontal,” and “parallel” are defined as including cases within ±10% of the standard definition. For example, vertical typically refers to an angle of 90° relative to a reference line, but in this application, vertical refers to cases including those within 80° to 100°. Unless otherwise expressly stated, comparative quantitative terms (such as “above” and “below”) are intended to cover the concept of equality. As an example, “above” can mean not only “greater than” in a mathematical sense but also “equal to.”

[0018] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. When used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that, when used herein, the terms “comprising,” “including,” “containing,” and / or “comprising” designate the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0019] In view of the technical problems mentioned in the background art, this application discloses a 3D printing device and its powder return mechanism. By connecting at least one air passage between the first powder return pipe connecting the first powder return tank and the first recovery chamber and the second powder return pipe connecting the second powder return tank and the second recovery chamber, the air passage between the first powder return pipe and the second powder return pipe is realized. When the air pressure in the recovery chamber hinders the powder from falling in the first powder return pipe or the second powder return pipe, the airflow in the first powder return pipe or the second powder return pipe will flow to the second powder return pipe or the first powder return pipe through the air passage, thereby releasing the air pressure in the recovery chamber and preventing the powder from clogging the first powder return pipe or the second powder return pipe.

[0020] In this application, the 3D printing equipment is a device that uses powder as raw material and constructs 3D components by molding the powder layer by layer. The powder is a powdered material, including nylon powder, metal powder, plastic powder, ceramic powder, and mixed powders. The powder may be, for example, thermoplastic rubber (TPR) or 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.

[0021] The thermoplastic elastomer is a type of elastomer that exhibits the elasticity of rubber at room temperature and the plasticity of molding at high temperatures. It is a physical mixture of copolymers or polymers (usually plastics and rubber) and is composed of materials with thermoplastic and elastomer properties. Thermoplastic plastics are generally relatively easy to manufacture, for example, through injection molding.

[0022] In some embodiments, the powder material may also be polypropylene, acrylonitrile butadiene styrene (ABS), polycarbonate (PC), PC-ABS, PLA, polystyrene, lignin, polyamide, polyamide foam, polyamide with additives such as glass or metal particles, methyl methacrylate-acrylonitrile-butadiene-styrene copolymer, absorbable materials such as polymer-ceramic composites, and other similar materials suitable for SLS printing processes.

[0023] The 3D printing equipment can be an SLM type 3D printing equipment, an SLS type 3D printing equipment, a DLMD type 3D printing equipment, an EBM type 3D printing equipment, or an SHS type 3D printing equipment, etc. In the following embodiments, the 3D printing equipment will be described as an SLM type 3D printing equipment, and correspondingly, the powder material will be described as a metal powder.

[0024] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. The technical solutions in the embodiments of the present application are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, not all of them. Based on the embodiments in the present application, all other embodiments and technical effects obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application. The terms "an embodiment," "implementation," or similar wording used throughout this specification mean that a specific feature, structure, or characteristic described together with an embodiment is included in at least one embodiment of the present application. Therefore, the appearance of the phrases "in an embodiment," "in an embodiment," and similar wording throughout this specification may (but does not necessarily) refer to the same embodiment.

[0025] In this application, the 3D printing equipment includes a forming platform, a powder spreading device, a powder return mechanism, an optical system, and a control device.

[0026] The forming platform has a forming chamber. The powder spreading device is used to spread powder in the forming chamber. The optical system is used to emit a light beam to illuminate the powder in the forming chamber. The control device is connected to the powder spreading device and the optical system to control the powder spreading device to spread powder in the forming chamber and to control the optical system to illuminate the powder in the forming chamber during a printing operation.

[0027] In one embodiment, the forming platform serves as a base for the powder spreading device to perform powder spreading operations, while also providing storage space for the forming chamber. In some examples, the forming chamber can be a cube, cuboid, or other shapes, the shape and size of which determine the range of 3D components that the 3D printing equipment can manufacture. For example, if the forming chamber is 600mm × 600mm × 400mm, then the maximum range of 3D components that the 3D printing equipment can print is no greater than 600mm × 600mm × 400mm.

[0028] In one embodiment, the molding platform has a molding chamber 1 (e.g., Figure 1 As shown, the forming chamber can be formed, for example, by a box disposed above the forming platform. In some examples, the box can be detachably disposed on the forming platform by means of, for example, screws, clips, etc. In some examples, an inert gas can be introduced into the forming chamber for protection so that the powder is prevented from oxidizing at high temperatures when the entire printing operation of the 3D printing equipment is performed in the forming chamber. The inert gas is, for example, nitrogen or argon, and the powder spreading device is disposed in the forming chamber.

[0029] In one embodiment, a component platform and a Z-axis drive mechanism are provided within the forming chamber. The component platform is used to attach 3D components that are formed layer by layer by an optical system. In one example, the component platform is in close contact with the inner wall of the forming chamber and moves vertically under the drive of the Z-axis drive mechanism during printing. In some examples, the component platform has a heat conduction function to maintain a certain high-temperature environment within the forming chamber to optimize print quality.

[0030] In one embodiment, the Z-axis drive mechanism is connected to the component platform and is used to move in a controlled vertical direction to adjust the distance between the component platform and the printing reference surface. Specifically, the control device controls the Z-axis drive mechanism to adjust the distance between the component platform and the printing reference surface according to the thickness of each printed layer, that is, to adjust the height of the forming area. The forming area is the area formed by the printing reference surface and the upper surface of the component platform or the upper surface of the 3D component during the printing process.

[0031] In one embodiment, the Z-axis drive mechanism includes a drive unit and a Z-axis moving unit. The drive unit drives the Z-axis moving unit so that the Z-axis moving unit moves the component plate along the Z-axis direction. For example, the drive unit is a drive motor. The drive unit is controlled by control commands output by the control device. These control commands include directional commands indicating whether the component plate is rising, falling, or stopping, and may even include parameters such as rotational speed / speed acceleration or torque / torque. This facilitates precise control of the rising distance of the Z-axis moving unit, enabling precise adjustment of the Z-axis. Here, the Z-axis moving unit may include, for example, a fixed rod fixed at one end to the component plate and an engaging moving assembly fixed to the other end of the fixed rod. The engaging moving assembly is driven by the drive unit to move the fixed rod along the Z-axis direction. An example of the engaging moving assembly is a limiting moving assembly with a toothed structure, such as a rack. For example, the Z-axis moving unit includes a lead screw and a positioning and moving structure screwed to the lead screw, wherein both ends of the lead screw are screwed to a drive unit, and the outer end of the positioning and moving structure is fixedly connected to the component plate. The positioning and moving structure may be, for example, a ball screw.

[0032] In one embodiment, the optical system includes a light source and a scanning galvanometer. The light source is used to controllably emit a light beam of a preset intensity. The light source can be a laser, such as a fiber laser or a YAG laser. The choice of light source depends on the type of printing equipment. For example, in SLM-type 3D printing equipment that requires melting metal, the light source can be a high-power-density laser. The scanning galvanometer can be deflected under the drive of its drive motor. For example, the drive motor of the scanning galvanometer is controlled by control commands output by the control device. By adjusting the deflection angle of the scanning galvanometer, the propagation direction of the light beam is adjusted to precisely position the light beam at any position on the printing reference surface. The control commands include directional commands indicating whether the scanning galvanometer rotates or stops, and may even include parameters such as rotational speed / rotational acceleration.

[0033] In one specific embodiment, the optical system includes a light source, a beam expander, a scanning galvanometer, an F-θ scanning lens, and a protective lens. The light beam emitted from the light source first passes through the beam expander, which increases the beam diameter, reduces the beam divergence angle, and decreases energy loss. After passing through the beam expander, the light beam reaches the scanning galvanometer, where the scanning galvanometer controls the beam's propagation direction. The F-θ scanning lens is positioned below the scanning galvanometer to converge the deflected light beam, allowing the light to form a focused spot at any position on the printing reference surface. The F-θ scanning lens also helps prevent optical distortion. The protective lens is positioned below the F-θ scanning lens, and the light beam finally passes through the protective lens to reach the printing reference surface. The protective lens prevents dust from affecting the optical components. In some examples, the optical system may consist of one or more components.

[0034] In one embodiment, the control device, in addition to being connected to the powder spreading device and the optical system, can also be connected to the Z-axis drive mechanism. This control device controls the vertical movement of the Z-axis drive mechanism during a printing operation to attach a solidified layer of the deposited pattern to the component platform to obtain the corresponding 3D component. Specifically, the control device is electrically connected to the drive motor of the Z-axis drive mechanism, causing the Z-axis drive mechanism to move vertically to attach the solidified layer of the deposited pattern to the component platform to obtain the corresponding 3D component.

[0035] In one embodiment, the control device is an electronic device that includes a processor, such as a computer device, an embedded device, or an integrated circuit with a CPU, such as a control board or main control board.

[0036] For example, the control device includes a processing unit, a storage unit, and multiple interface units. Each interface unit is connected to an independently installed device in the 3D printing equipment, such as a powder spreading device, an optical system, or a Z-axis drive mechanism, and transmits data through the interface. The control device also includes at least one of the following: a prompting device, a human-computer interaction device, etc. The interface unit determines its interface type according to the connected device, which includes, but is not limited to: a universal serial interface, a video / image interface, and an industrial control interface, etc.

[0037] For example, the interface unit includes: a USB interface, an HDMI interface, and an RS232 interface. Multiple USB and RS232 interfaces are available. The USB interfaces can connect to human-computer interaction devices, etc. The RS232 interfaces connect to the powder spreading device and the Z-axis drive mechanism, and the HDMI interfaces connect to the optical system. The storage unit is used to store files required for 3D printing. These files include: program files and configuration files required for CPU operation, etc.

[0038] The storage unit includes non-volatile memory and a system bus. Examples of the non-volatile memory include solid-state drives (SSDs) or USB flash drives. The system bus connects the non-volatile memory to the CPU, wherein the CPU may be integrated into the storage unit or packaged separately from the storage unit and connected to the non-volatile memory via the system bus.

[0039] The processing unit includes at least one of the following: a CPU or a chip with an integrated CPU, a programmable logic device (FPGA), and a multi-core processor. The processing unit also includes memory, registers, and other storage devices for temporary data storage.

[0040] The processing unit serves as an industrial control unit that controls the sequential execution of each device. For example, after controlling the Z-axis drive mechanism to move the component platform to a position a distance from the preset printing reference surface, the processing unit transmits a control signal to the drive motor of the powder spreading device to control the powder spreading device to perform powder spreading operations. After the powder spreading device completes the powder spreading, the control device transmits control signals to the motors of the light source and galvanometer of the optical system. After the optical system completes the curing of the powder on the component platform, it controls the Z-axis drive mechanism to adjust and move the component platform to a new position a distance from the preset printing reference surface, repeating the above printing process until the printing of the entire 3D component is completed.

[0041] It should be understood that when the powder spreading device in a 3D printing equipment performs powder spreading operations, excess powder is recycled into the powder recycling chamber through the powder return pipe. However, powder falling solely by gravity may stick to the pipe wall, or when a large amount of powder enters the pipe, the air pressure in the powder recycling chamber connected to the pipe may hinder the powder from falling, causing the powder to clog the pipe. Therefore, a powder return mechanism is needed that can eliminate the problem of powder return pipe clogging when recycling excess powder.

[0042] In view of this, this application provides a toner return mechanism for 3D printing equipment. Please refer to [link / reference]. Figure 1 and Figure 2 , Figure 1 The diagram shown is a three-dimensional structural schematic of the powder return mechanism and the molding chamber of the 3D printing equipment connected thereto, as described in one embodiment of this application, from a single perspective. Figure 2 The figure shows a three-dimensional structural schematic diagram of the powder return mechanism in one embodiment of this application from another perspective. As shown, the 3D printing equipment includes a forming chamber 1 and a powder spreading device 11 disposed within the forming chamber, wherein the powder spreading device 11... Figure 1 The material is reciprocated in the first direction indicated by arrow A and the second direction indicated by arrow B to lay the powder.

[0043] In this application, the powder return mechanism 2 for a 3D printing equipment includes a first powder return trough 21, a second powder return trough 22, a first recovery chamber 31, a second recovery chamber 32, a first powder return pipe 41, and a second powder return pipe 42. The first powder return trough 21 and the second powder return trough 22 are respectively disposed on opposite sides of the bottom surface of the forming chamber 1 to recover excess powder during the reciprocating powder application by the powder spreading device 11. Specifically, in one embodiment, the first powder return trough 21 is disposed on the bottom surface of the forming chamber 1 facing direction A, and the second powder return trough 22 is disposed on the bottom surface of the forming chamber 1 facing direction B. After the powder spreading device 11 completes the powder spreading operation in the first or second direction, it pushes excess powder into the first powder return trough 21 or the second powder return trough 22 for powder recovery. In one embodiment, the molding chamber 1 is also provided with a grid (not shown) covering the top of the first powder return trough 21 and the second powder return trough 22. The grid can both let excess powder fall into the powder return trough and prevent the powder in the powder return trough from forming dust and escaping into the molding chamber.

[0044] The first recycling bin 31 and the second recycling bin 32 are respectively disposed on the lower side of the molding chamber 1 to collect powder from the first powder return tank 21 and the second powder return tank 22, respectively. Specifically, in one embodiment, the first recycling bin 31 is disposed inside the 3D printing equipment base and is located on the same side as the first powder return tank 21, and the second recycling bin 32 is disposed inside the 3D printing equipment base and is located on the same side as the second powder return tank 22, so as to facilitate the establishment of a shorter connection path between the powder return tank and the recycling bin.

[0045] The first powder return pipe 41 connects the first powder return trough 21 and the first recovery chamber 31 to transport powder from the first powder return trough 21 to the first recovery chamber 31. The second powder return pipe 42 connects the second powder return trough 22 and the second recovery chamber 32 to transport powder from the second powder return trough 22 to the first recovery chamber 32. At least one air passage pipe 43 connects the first powder return pipe 41 and the second powder return pipe 42 to adjust or release the air pressure inside the first powder return pipe 41 or the second powder return pipe 42, so that excess powder can fall smoothly into the first recovery chamber 31 or the second recovery chamber 32 without clogging the first powder return pipe 31 or the second powder return pipe 32. Specifically, in one embodiment, when a large amount of excess powder such as Figure 2 As indicated by arrow C, when the powder falls from the first powder return trough 21 along the first powder return pipe 41, the presence of air pressure in the first recovery chamber 31 will cause the powder in the first powder return pipe 41 to undergo a process similar to... Figure 2 As indicated by the upward obstruction in the direction of the middle arrow D, in this case, the air passage 43 causes the airflow in the first powder return pipe 41 to flow through the air passage 43 to the second powder return pipe 42, thereby regulating or releasing the air pressure in the first powder return pipe 41 and the first recovery chamber 31, so as to eliminate the obstruction force on the powder in the first powder return pipe 41, so that the powder in the first powder return pipe 41 can fall smoothly into the first recovery chamber 31.

[0046] In one embodiment, the air duct and the dust return pipe can be configured as a single integral component to facilitate installation and prevent dust escaping. For example, the air duct 43 is integrally formed with the first dust return pipe 41. Alternatively, the air duct 43 is integrally formed with the second dust return pipe 42. Yet another example is that the air duct 43 is integrally formed with the first dust return pipe 41 and the second dust return pipe 42.

[0047] In another embodiment, the air duct and the dust return pipe can be configured as separate components to facilitate production, processing, and transportation. For example, the air duct 43 is detachably connected to the first dust return pipe 41. Similarly, the air duct 43 is detachably connected to the second dust return pipe 42. Furthermore, the air duct 43 is detachably connected to both the first dust return pipe 41 and the second dust return pipe 43. During actual disassembly and installation, sealing elements are added at the connections of the first dust return pipe 41, the second dust return pipe 42, and the air duct 43 to ensure a good seal between the installed air duct and the dust return pipe, preventing dust from escaping.

[0048] Please see Figure 3 , Figure 3 The figure shows a three-dimensional structural diagram of the powder return pipe and gas pipeline in one embodiment of this application from a perspective. As shown, the gas pipeline 43 includes at least two pipe sections 431 and 432 that can be assembled and connected, and connecting sections 433 and 434 that are respectively connected to the first powder return pipe 41 and the second powder return pipe 42. The lengths of the pipe sections 431 and 432 can be set according to requirements.

[0049] In one embodiment, the pipe portion of the gas passage 43 is configured as a detachable component to facilitate cleaning of residual powder in the middle of the gas passage 43. Specifically, in one embodiment, the gas passage 43 includes two pipe portions 431 and 432 that can be assembled and communicated.

[0050] In another embodiment, the connecting portion of the air passage 43 can be integrally formed with the dust return pipe to reduce the risk of dust escaping at the connection point. For example, the connecting portion 433 and the first dust return pipe 41 are integrally formed. Alternatively, the connecting portion 434 and the second dust return pipe 42 are integrally formed. Furthermore, the connecting portions 433 and 434 are integrally formed with the first dust return pipe 41 and the second dust return pipe 42, respectively. In another embodiment, the connecting portion of the air passage 43 can be detachably connected to the dust return pipe for ease of production, processing, and transportation. For example, the connecting portion 433 and the first dust return pipe 41 are detachably connected. Alternatively, the connecting portion 434 and the second dust return pipe 42 are detachably connected. Furthermore, the connecting portions 433 and 434 are detachably connected with the first dust return pipe 41 and the second dust return pipe 42, respectively.

[0051] In one embodiment, refer again Figure 1 and Figure 2 The powder return trough is funnel-shaped to maximize the collection of excess powder from the powder spreading device 11 during powder application at its upper part and to quickly gather the collected powder at its lower part for transfer to the powder return pipe. Specifically, for example, the first powder return trough 21 is funnel-shaped. Similarly, the second powder return trough 22 is funnel-shaped. Furthermore, both the first and second powder return troughs 21 and 22 may be funnel-shaped. In other embodiments, the shape of the powder return trough can be any shape with openings at the top and bottom, as long as it has an opening at the top for receiving powder and a powder discharge port at the bottom.

[0052] In another embodiment, the powder return pipe is connected to the bottom end of one side wall of the powder return trough, so that the collected powder can quickly enter the powder return pipe under the action of gravity, avoiding the situation where there is a bend at the connection between the powder return pipe and the powder return trough, which would affect the falling of the powder. Specifically, for example, the first powder return pipe 41 is connected to the bottom end of one side wall of the first powder return trough 21. Another example is that the second powder return pipe 42 is connected to the bottom end of one side wall of the second powder return trough 22. Yet another example is that the first powder return pipe 41 is connected to the bottom end of one side wall of the first powder return trough 21, and the second powder return pipe 42 is connected to the bottom end of one side wall of the second powder return trough 22.

[0053] In one embodiment, the relative position between the powder return pipe and the recovery bin is set so that the powder can quickly fall from the powder return pipe into the recovery bin. For example, the included angle between the planes where the first powder return pipe 41 and the first recovery bin 31 are located is set (e.g., ...). Figure 1 The included angle α shown is less than 45°. For example, the included angle between the planes where the second powder return pipe 42 and the second recovery chamber 32 are located (e.g., ...) is set... Figure 1 The included angle β shown is less than 45°. For example, the included angle between the plane where the first powder return pipe 41 and the first recovery chamber 31 are located is less than 45°, and the included angle between the plane where the second powder return pipe 42 and the second recovery chamber 32 are located is less than 45°. Preferably, the above included angles are in the range of 30° to 45°, for example, approximately 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, or 45°.

[0054] In one embodiment, a vibration device is also provided on the powder return pipe to allow the powder adhering to the wall of the powder return pipe to fall off the wall under the action of an external force. For example, a vibration device is provided on the first powder return pipe 41. Another example is that a vibration device is provided on the second powder return pipe 42. Yet another example is that a vibration device is provided on both the first powder return pipe 41 and the second powder return pipe 42. In one example, the vibration device may be a pneumatic device.

[0055] In practical use, most of the powder may accumulate at the connection between the air duct and the return powder pipe, or at the connection between the recovery bin and the return powder pipe. To further remove the powder accumulated at the connection, in one embodiment, the vibration device is installed on the opposite side of the first or second return powder pipe to the side connected to the air duct, to facilitate shaking off the powder accumulated at and near the connection between the air duct and the return powder pipe. Specifically, the vibration device 411 (e.g., Figure 2 (As shown) is installed on the opposite side of the first powder return pipe 41 to the side connected to the air passage pipe 43; or the vibration device 421 (as shown) is installed on the opposite side of the first powder return pipe 41 to the side connected to the air passage pipe 43; Figure 2 (As shown in the diagram) The vibrating device is located on the opposite side of the second powder return pipe 42, opposite to the connection side of the air passage pipe 43. In another embodiment, the vibrating device is located on the first powder return pipe or the second powder return pipe and between the first recovery bin or the second recovery bin and the connection point of the air passage pipe and the first powder return pipe or the second powder return pipe, to facilitate shaking off the powder accumulated at and near the recovery bin opening. Specifically, the vibrating device (not shown) is located on the first powder return pipe 41 and between the first recovery bin 31 and the connection point of the air passage pipe 43 and the first powder return pipe 41; or the vibrating device (not shown) is located on the second powder return pipe 42 and between the second recovery bin 32 and the connection point of the air passage pipe 43 and the second powder return pipe 42.

[0056] In one embodiment, the air passage is connected to a negative pressure pipe (not shown) for applying negative pressure airflow to the air passage. By actively applying negative pressure to the air passage, the airflow inside the air passage is extracted, thereby releasing the air pressure in the recovery chamber and the powder return pipe. For example, a vacuum pump (not shown) can be installed on the negative pressure pipe to assist in air extraction, which helps to release the air pressure in the recovery chamber and the powder return pipe and avoids powder blockage. In actual implementation, a filter element is installed on the negative pressure pipe to filter dust that may be carried in the airflow from the air passage.

[0057] In one embodiment, a sensor for detecting the pressure inside the first and / or second recycling bins may also be provided to facilitate powder dispensing operations in real time based on the pressure inside the recycling bins. In one example, the sensor is electrically connected to the aforementioned vibration device. When the sensor detects that the air pressure inside the recycling bin is greater than a preset threshold, the vibration device vibrates to assist in powder dispensing. In another example, the sensor is electrically connected to the aforementioned vacuum pump. When the sensor detects that the air pressure inside the recycling bin is greater than a preset threshold, the vacuum pump performs a pumping operation to release the air pressure in the recycling bins and powder return pipes, preventing powder blockage.

[0058] In summary, the 3D printing equipment and its powder return mechanism disclosed in this application, on the one hand, achieve airflow communication between the first powder return pipe connecting the first powder return tank and the first recovery chamber, and the second powder return pipe connecting the second powder return tank and the second recovery chamber, so that when the air pressure in the recovery chamber obstructs the powder from falling into the first or second powder return pipe, the airflow in the first or second powder return pipe will flow through the airflow pipe to the second or first powder return pipe, thereby releasing the air pressure in the recovery chamber and preventing powder from clogging the first or second powder return pipe. On the other hand, the connection relationship and relative position of the powder return tank, powder return pipe, airflow pipe, and recovery chamber facilitate the rapid falling of powder from the powder return pipe into the recovery chamber. Furthermore, by incorporating a vibration device, a negative pressure pipe, and a sensing device, the handling of falling powder is further enhanced, further preventing powder clogging.

[0059] The above embodiments are merely illustrative of the inventive essence and beneficial effects of this application, and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the principles and scope of this application. Therefore, all equivalent modifications or alterations achieved by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A powder return mechanism for a 3D printing device, the 3D printing device comprising a forming chamber and a powder spreading device disposed within the forming chamber, characterized in that, The powder return mechanism includes: The first and second powder troughs are respectively located on opposite sides of the bottom surface of the forming chamber to collect excess powder when the powder spreading device repeatedly spreads the powder. The first and second recycling bins are respectively located on the lower side of the forming chamber to collect powder from the first and second powder return tanks respectively. A first powder return pipe and a second powder return pipe, wherein the first powder return pipe is connected to the first powder return tank and the first recovery bin, and the second powder return pipe is connected to the second powder return tank and the second recovery bin; wherein at least one air passage pipe is connected between the first powder return pipe and the second powder return pipe.

2. The powder return mechanism according to claim 1, characterized in that, The gas pipeline is integrally formed with the first powder return pipe and / or the second powder return pipe, or the gas pipeline is detachably connected to the first powder return pipe and / or the second powder return pipe.

3. The powder return mechanism according to claim 1, characterized in that, The gas pipeline includes at least two pipe sections that can be assembled and connected, and a connecting section that is respectively connected to the first powder return pipe and the second powder return pipe. The connecting section is integrally formed with the first powder return pipe and / or the second powder return pipe, or the connecting section is detachably connected to the first powder return pipe and / or the second powder return pipe.

4. The powder return mechanism according to any one of claims 1-3, characterized in that, The first powder return trough and / or the second powder return trough are configured as funnels.

5. The powder return mechanism according to claim 4, characterized in that, The first powder return pipe is connected to the bottom end of one side wall of the first powder return trough, and / or the second powder return pipe is connected to the bottom end of one side wall of the second powder return trough.

6. The powder return mechanism according to any one of claims 1-3 or 5, characterized in that, The angle between the first powder return pipe and the plane where the first recycling bin is located is less than 45°, and / or the angle between the second powder return pipe and the plane where the second recycling bin is located is less than 45°.

7. The powder return mechanism according to claim 6, characterized in that, The included angle is in the range of 30° to 45°.

8. The powder return mechanism according to any one of claims 1-3, 5, or 7, characterized in that, A vibration device is provided on the first powder return pipe and / or the second powder return pipe.

9. The powder return mechanism according to claim 8, characterized in that, The vibration device is installed on the opposite side of the first or second powder return pipe to the side connected to the gas pipeline.

10. The powder return mechanism according to claim 8, characterized in that, The vibration device is installed on the first or second return powder pipe and is located between the first or second recovery bin and the connection between the air pipeline and the first or second return powder pipe.

11. The powder return mechanism according to claim 1, characterized in that, The gas pipeline is connected to a negative pressure pipeline for applying negative pressure airflow to the gas pipeline.

12. The powder return mechanism according to claim 1 or 11, characterized in that, The first and / or second recycling bins are equipped with sensors for detecting the pressure inside the bins.

13. A 3D printing device, characterized in that, include: A molding platform is provided with a molding chamber. The molding platform has a molding compartment, and a component platform and a Z-axis drive mechanism are provided inside the molding compartment. The component platform is used to attach 3D components that are formed layer by layer by irradiation by an optical system. The Z-axis drive mechanism is connected to the component platform and is used to move in a controlled manner along the vertical direction to adjust the distance between the component platform and the printing reference surface. A powder spreading device is installed in the molding chamber to spread powder in the molding chamber. The powder recovery mechanism as described in any one of claims 1-12 is used to recover excess powder from the powder spreading device during powder spreading. An optical system is used to emit a light beam to illuminate the powder inside the molding chamber; A control device, connected to the optical system, Z-axis drive mechanism, and powder spreading device, is used to control the powder spreading device to spread powder into the forming chamber during printing, control the optical system to irradiate the powder in the forming chamber, and control the Z-axis drive mechanism to move vertically during printing to attach a solidified layer of the deposited pattern on the component platform to obtain the corresponding 3D component.

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