Powder feeding system and 3D printing equipment

Abstract

The utility model discloses a powder feeding system and 3D printing equipment, and the powder feeding system comprises a powder feeding pipeline used for conveying powder in the pipeline through input airflow; the powder storage device is arranged on the powder feeding pipeline and used for conveying the stored powder into the powder feeding pipeline; the first filtering container is arranged in the 3D printing equipment, communicates with the powder feeding pipeline and comprises a first cavity, a first powder inlet and a first gas outlet, and the first powder inlet and the first gas outlet are formed in the first cavity; the second filtering container is arranged in the 3D printing equipment, the second filtering container and the first filtering container are connected to the powder feeding pipeline in parallel, and the second filtering container comprises a second cavity, and a second powder inlet and a second gas outlet which are formed in the second cavity; the valve assembly comprises a plurality of valves which are arranged on the channels of the powder feeding pipeline and the first filtering container and the second filtering container respectively and used for switching the channels of the powder feeding pipeline and the first filtering container and the second filtering container.

Description

Technical Field

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

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

[0003] Taking SLM type 3D printing equipment as an example, in the powder feeding process of existing SLM type 3D printing equipment, in order to ensure the safety of workers and reduce the workload of workers, a pneumatic powder feeding system is usually used to transport the powder used for printing to the 3D printing equipment. For example, a fan is used to provide a circulating airflow in a closed powder feeding pipeline so that the powder in the powder feeding pipeline is transported to the 3D printing equipment.

[0004] The existing pneumatic powder delivery system usually has only one filter container for separating gas and solid powder. When the filter container is blocked or there is a problem with the powder delivery pipeline where the filter container is located, the fan needs to be stopped for processing. In order to ensure the safety of powder delivery, that is, to avoid too much oxygen from entering the powder delivery pipeline, when the fan stops during the powder delivery process, it is necessary to pass inert gas into the powder delivery pipeline for air washing before delivering the powder. Such frequent fan start and stop and air washing will reduce the powder delivery efficiency. Therefore, how to improve the powder delivery efficiency and safety of pneumatic powder delivery is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of the shortcomings of the above-mentioned related technologies, the purpose of the present application is to provide a powder feeding system and a 3D printing device to overcome the technical problems existing in the above-mentioned related technologies on how to improve the powder feeding efficiency and safety of pneumatic powder feeding.

[0006] To achieve the above-mentioned purpose and other related purposes, the first aspect of the present application provides a powder delivery system for delivering powder to a 3D printing device, the powder delivery system comprising: a powder delivery pipeline for delivering powder in the pipeline through an input airflow; a powder storage device, arranged on the powder delivery pipeline, for delivering the stored powder to the powder delivery pipeline; a first filter container, arranged in the 3D printing device and connected to the powder delivery pipeline, comprising a first cavity, and a first powder inlet and a first gas outlet arranged on the first cavity, for separating powder and gas entering from the first powder inlet, so as to discharge the gas from the first gas outlet to the powder delivery pipeline. and collects the powder in the first cavity; a second filter container is arranged in the 3D printing device and connected to the powder delivery pipeline in parallel with the first filter container, comprising a second cavity, and a second powder inlet and a second gas outlet arranged on the second cavity, for separating the powder and gas entering from the second powder inlet, so as to discharge the gas from the second gas outlet to the powder delivery pipeline, and collect the powder in the second cavity; a valve assembly comprises a plurality of valves, which are respectively arranged on the passages between the powder delivery pipeline and the first filter container and the second filter container, for switching the passages between the powder delivery pipeline and the first filter container and the second filter container.

[0007] According to a second aspect of the present application, there is provided a 3D printing device, the 3D printing device comprising: a forming table, arranged in a forming chamber of the 3D printing device, the forming table comprising a forming table body and a forming tank; a component platform and a Z-axis driving mechanism are arranged in the forming tank, the component platform is used to attach a 3D object formed by layer-by-layer solidification by irradiation of an optical system, the Z-axis driving mechanism is connected to the component platform, and is used to controllably move vertically to adjust the distance between the component platform and a printing reference plane; a first filtering container is arranged in the 3D printing device and connected to a powder delivery pipeline, comprising a first cavity, and a first powder inlet and a first gas outlet arranged on the first cavity, for separating powder and gas entering from the first powder inlet, so as to discharge the gas from the first gas outlet to the powder delivery pipeline, and collect the powder in the first cavity; a second filtering container is arranged in the 3D printing device and connected to the powder delivery pipeline The first filter container is connected in parallel to the powder delivery pipeline, including a second cavity, and a second powder inlet and a second gas outlet arranged on the second cavity, which are used to separate the powder and gas entering from the second powder inlet, so as to discharge the gas from the second gas outlet to the powder delivery pipeline, and collect the powder in the second cavity; wherein the passages between the powder delivery pipeline and the first filter container and the second filter container can be switched by a plurality of valves respectively arranged on the passages between the powder delivery pipeline and the first filter container and the second filter container; an optical system, which is used to emit a light beam to irradiate the powder in the molding area of ​​the molding tank; a control device, which is connected to the optical system and the Z-axis drive mechanism, is used to control the optical system to irradiate the powder in the molding area under the printing operation, and to control the Z-axis drive mechanism to move vertically under the printing operation, so as to attach and deposit the pattern solidified layer on the component platform to obtain the corresponding 3D object.

[0008] In summary, the powder feeding system and 3D printing device provided by the present application, by arranging a first filter container and a second filter container in the 3D printing device, connecting the first filter container and the second filter container in parallel in a powder feeding pipeline, and arranging a valve assembly for switching the passages between the powder feeding pipeline and the first filter container and the second filter container, can enable the powder feeding system to use one of the filter containers to feed powder to the 3D printing device. If the filter container is blocked or needs to be cut off from the powder feeding pipeline, the valve assembly can be used to switch the powder feeding pipeline to another filter container, thereby avoiding stopping the fan and frequent air washing during the powder feeding process, thereby improving the powder feeding efficiency and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The features and advantages of the inventions of 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:

[0010] Figure 1 It is a schematic diagram of a circulation loop in which a first filter container is connected to a powder delivery pipeline in a powder delivery system in one embodiment of the present application.

[0011] Figure 2 It is a schematic diagram of a circulation loop in which a second filter container is connected to a powder delivery pipeline in a powder delivery system in one embodiment of the present application.

[0012] Figure 3 Display as Figure 1 A partial enlarged schematic diagram of the position F1 in the illustrated embodiment.

[0013] Figure 4 Display as Figure 2 A partial enlarged schematic diagram of F2 in the illustrated embodiment.

[0014] Figure 5 Shown is a schematic diagram of a gas passage for pre-filling the powder delivery pipeline with inert gas in one embodiment of the present application.

[0015] Figure 6 It is a schematic diagram of the gas passage when the powder screening device screens the recovered powder on the forming table in one embodiment of the present application.

[0016] Figure 7 It is a schematic diagram of the gas circulation passage when the powder screening device screens the recovered powder in the powder recovery barrel in one embodiment of the present application.

[0017] Figure 8 It is a schematic diagram showing that the third filtering container in the powder screening device in one embodiment of the present application is connected with the powder feeding pipeline.

[0018] Fig. 9 It is a schematic diagram showing that the fourth filtering container in the powder screening device in one embodiment of the present application is connected with the powder feeding pipeline. DETAILED DESCRIPTION

[0019] The following is an explanation of the implementation of the present application by means of specific embodiments. People familiar with the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification.

[0020] In the following description, with reference to the accompanying drawings, several embodiments of the present application are described. It should be understood that other embodiments may also be used, and mechanical composition, structure, electrical and operational changes may be made without departing from the spirit and scope of the present disclosure. 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 of the published patents. The terms used here are only to describe specific embodiments and are not intended to limit the present application. Spatially related terms, such as "upper", "lower", "left", "right", "below", "below", "lower", "above", "upper", etc., may be used in the text to facilitate the description of the relationship between an element or feature shown in the figure and another element or feature.

[0021] Although the terms first, second, etc. are used to describe various elements or parameters in this article in some instances, these elements or parameters should not be limited by these terms. These terms are only used to distinguish one element or parameter from another element or parameter. For example, the first filter container can be referred to as the second filter container, and similarly, the second filter container can be referred to as the first filter container without departing from the scope of the various described embodiments. The first filter container and the second filter container are both describing a filter container, but unless the context clearly indicates otherwise, they are not the same filter container.

[0022] The present application is further described in detail below in conjunction with 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 embodiments of a part of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application. The "one embodiment", "implementation method" or similar words mentioned in the whole text of this specification mean that the specific features, structures or characteristics described together with the implementation method are included in at least one implementation method of the present application. Therefore, in the whole text of this specification, the appearance of the phrases "in one embodiment", "in an embodiment", "in an embodiment" and similar words may (but not necessarily) relate to the same embodiment.

[0023] As described in the background technology, in a pneumatic powder delivery system, there is usually only one filter container for separating gas and solid powder. When the filter container is blocked or there is a problem with the powder delivery pipeline where the filter container is located, the fan needs to be stopped for processing, and air washing is required before re-delivering the powder. However, frequent start and stop of the fan and air washing will reduce the powder delivery efficiency. In addition, ensuring that the powder delivery pipeline is always in a safe atmosphere and isolated from the outside air (especially from oxygen) during the powder delivery process is an important factor in ensuring safe production.

[0024] In view of this, the present application proposes a powder feeding system and a 3D printing device. By arranging a first filter container and a second filter container in the 3D printing device, connecting the first filter container and the second filter container in parallel in a powder feeding pipeline, and arranging a valve assembly for switching the passages between the powder feeding pipeline and the first filter container and the second filter container, the powder feeding system can use the valve assembly to switch the powder feeding pipeline to another filter container when using one of the filter containers to feed powder to the 3D printing device if the filter container is blocked or needs to be cut off from the powder feeding pipeline, thereby avoiding stopping the fan and frequent air washing during the powder feeding process, thereby improving the powder feeding efficiency and safety.

[0025] In the present application, the 3D printing device is a device that uses powder as raw material and solidifies the powder layer by layer to construct a 3D object. The powder is a powder material, and the powder includes metal powder, plastic powder, ceramic powder, mixed powder, etc. The 3D printing device can be an SLM type 3D printing device, an SLS type 3D printing device, a DLMD type 3D printing device, an EBM type 3D printing device, and an SHS type 3D printing device. In the following embodiments, the 3D printing device is an SLM type 3D printing device as an example.

[0026] In one embodiment, see Figures 1 to 4 , Figure 1 It is a schematic diagram of a circulation loop in which the first filter container is connected to the powder delivery pipeline in a powder delivery system in one embodiment of the present application. Figure 2 It is a schematic diagram of a circulation loop in which the second filter container is connected to the powder delivery pipeline in the powder delivery system in one embodiment of the present application. Figure 3 Display as Figure 1 A partial enlarged schematic diagram of F1 in the embodiment shown, Figure 4 Display as Figure 2The partial enlarged schematic diagram at F2 in the illustrated embodiment, as shown in the figure, the powder delivery system includes a powder delivery pipeline L1, a powder storage device 10, a first filter container 110, a second filter container 111, and a valve assembly 12. Specifically, the powder delivery pipeline L1 is used to transport the powder in the pipeline through the input air flow. The powder storage device 10 provided on the powder delivery pipeline L1 is used to transport the stored powder to the powder delivery pipeline L1. The first filter container 110 is used to separate the powder and gas entering from its first powder inlet 1102, discharge the gas from the first gas outlet 1101 to the powder delivery pipeline L1, and collect the powder in its first cavity 1103. The second filter container 111 is used to separate the powder and gas entering from its second powder inlet 1112, discharge the gas from the second gas outlet 1111 to the powder delivery pipeline L1, and collect the powder in its second cavity 1113. The valve components 12 respectively arranged on the passages between the powder delivery pipeline L1 and the first filter container 110 and the second filter container 111 are used to switch the passages between the powder delivery pipeline L1 and the first filter container 110 and the second filter container 111. This ensures that when a problem occurs in the filter container for powder delivery, the valve component 12 can be used to directly switch another filter container to be connected to the powder delivery pipeline L1 without stopping the fan to deliver powder to the 3D printing device.

[0027] In one embodiment, the powder delivery pipeline L1 is used to transport the powder in the pipeline through the input airflow. In one example, the airflow input in the powder delivery pipeline L1 is generated by an airflow generating device 17 connected to the powder delivery pipeline L1. For example, the airflow generating device 17 is a fan or a vacuum pump. The airflow generated by the airflow generating device 17 can drive the powder to move in the powder delivery pipeline L1, so that the powder delivery pipeline L1 transports the powder and gas to the first filter container 110 or the second filter container 111. It should be noted here that in order to distinguish it from other subsequent airflow generating devices, in the embodiment, the airflow generating device in the powder delivery pipeline is also referred to as the first airflow generating device.

[0028] In one embodiment, in order to ensure the safety of the powder delivery process and avoid the explosion caused by excessive dust concentration in the air due to open powder delivery, the powder delivery pipeline is a closed pipeline. Figure 1 and Figure 2 As shown, the powder delivery pipeline L1 is a closed pipeline shown by the dotted line in the figure. One end of the closed powder delivery pipeline L1 is connected to the blowing port of the first airflow generating device 18, and the other end of the closed powder delivery pipeline L1 is connected to the air inlet of the first airflow generating device 18.

[0029] It should be understood that the pipelines described in the present application (powder delivery pipeline, pre-filling pipeline, first back-blowing pipeline, powder screening pipeline, and second back-blowing pipeline, etc.) are paths for transferring at least one of powder, recovered powder, impurities and gas between the various components of the powder delivery system (e.g., powder storage device, first filter container), so that the pipelines widely include pipes, hoses, or other structures such as one or more lumens adapted to transfer powder and / or gas between two ends. Among them, the materials of the powder delivery pipeline include but are not limited to polyvinyl chloride "PVC" materials, thermoplastic resin "PE" materials, polypropylene "PP" materials, etc. The valve in the pipeline is used to control the conduction and closing of the pipeline. In one embodiment, the valve in the pipeline is a pneumatic valve, and the pneumatic valve can be opened or closed by changes in gas pressure.

[0030] In order to avoid accidents such as explosions due to high oxygen content in the powder delivery pipeline L1 during the powder delivery process and to ensure the safety of the staff, in one embodiment, please refer to Figure 5 , shows a schematic diagram of a gas passage for pre-filling the powder delivery pipeline with inert gas in one embodiment of the present application. As shown in the figure, the powder delivery system also includes a pre-filling pipeline L3, and a second gas source (not shown) is provided on the pre-filling pipeline L3. When the pre-filling pipeline L3 is connected to the powder delivery pipeline L1 and the second gas source is started, the second gas source pre-fills the powder delivery pipeline L1 with inert gas through the pre-filling pipeline L3. After the pre-filling is completed, the powder delivery pipeline L1 contains a large amount of inert gas, so that the safety of powder transportation can be guaranteed and explosion caused by excessive oxygen can be avoided.

[0031] In a specific embodiment, one end of the pre-filling pipeline L3 is connected to the second gas source, and the other end is connected to the powder delivery pipeline L1. The powder storage device 10 is connected in series in the pre-filling pipeline L3. The inert gas generated by the second gas source enters the pre-filling pipeline L3, and then the inert gas enters the upper space of the powder storage device 10 (for example, Figure 5 The space above the curve in the powder storage device 10 where there is no powder) then enters the pre-filling pipeline L3 through the upper space of the powder storage device 10, and enters the powder delivery pipeline L1 along the direction indicated by the arrow in the pre-filling pipeline L3, thereby pre-filling the powder delivery pipeline L1 with inert gas.

[0032] It should be noted that when the inert gas is pre-filled into the powder delivery pipeline L1, the valves on the pre-filling pipeline L3 are all opened to open the communication passage between the pre-filling pipeline L3 and the powder delivery pipeline L1, and the various valves on the first reverse blowing pipeline L2 are closed, and the multiple valves (12a, 12b, 12c, 12d) in the powder delivery pipeline L1 are opened to ensure that the inert gas enters the powder delivery pipeline L. For example, Figure 5 As shown, the inert gas is fed from the pre-filling pipeline L3 into the powder delivery pipeline L1 along the direction indicated by the arrow on the pre-filling pipeline L3.

[0033] The second gas source is an inert gas source. In one embodiment, the inert gas source is, for example, a nitrogen gas source or an argon gas source.

[0034] After the pre-charging is completed, for example, after the oxygen content in the powder delivery pipeline L1 reaches a preset oxygen content threshold, or after a fixed pre-charging time, the valve on the pre-charging pipeline L3 and the second gas source are closed, the various valves on the first reverse blowing pipeline L2 continue to remain closed, and a portion of the multiple valves (12a, 12b, 12c, 12d) in the powder delivery pipeline L1 are opened to open the communication passage between the first filter container or the second filter container and the powder delivery pipeline L1 for powder delivery. Further, in one embodiment, an oxygen content sensor 153 is also provided in the powder delivery pipeline L1, and the oxygen content sensor 153 is used to measure the oxygen content in the powder delivery pipeline L1.

[0035] like Figure 1 and Figure 2 As shown, the powder storage device 10 is disposed on the powder delivery pipeline L1 , and the powder storage device 10 is used to deliver the stored powder to the powder delivery pipeline L1 .

[0036] In one embodiment, the powder storage device 10 includes a powder storage container 100 and a quantitative feeding mechanism 101, wherein the quantitative feeding mechanism 101 is connected to the powder storage container 100, and the quantitative feeding mechanism 101 is used to quantitatively input the powder in the powder storage container 100 into the powder delivery pipeline L1. In one example, a valve is provided between the quantitative feeding mechanism 101 and the powder storage container 100, and after the pre-filling is completed, the valve between the quantitative feeding mechanism 101 and the powder storage container 100 is opened so that the quantitative feeding mechanism 101 can quantitatively input the powder into the powder delivery pipeline L1. In this embodiment, by providing a quantitative feeding mechanism, the powder can be uniformly input into the powder delivery pipeline L1, thereby preventing the powder from blocking the powder delivery pipeline.

[0037] In one embodiment, the powder storage container has a cavity for accommodating powder, an opening for conveying powder, and an injection port for injecting powder. For example, the injection port for powder includes a manual injection port and an automatic injection port. The user injects the powder into the cavity of the powder storage container from the manual injection port, and the powder screening mechanism described later injects the powder into the cavity of the powder storage container from the automatic injection port, and the powder is output from the opening of the powder storage container to the quantitative feeding mechanism. Furthermore, an inert gas input port and an inert gas output port are also provided on the powder storage container, and the inert gas input port and the inert gas output port are both arranged in the upper space of the powder storage container, so that the inert gas generated by the second gas source can enter the powder storage container from the inert gas input port and enter the pre-filling pipeline from the inert gas output port.

[0038] In one embodiment, in order to monitor whether the material level of the powder in the powder storage container is lower than the preset material level threshold, the powder storage container is also provided with a sensor for material level detection. When the sensor determines that the material level in the powder storage container is lower than the preset material level threshold, the powder delivery system can issue a warning to the user. For example, the powder delivery system also includes a display screen, and the powder delivery system displays the information that the material level is lower than the preset material level threshold on the display screen. For another example, the powder delivery system also includes a sound alarm device, and the powder delivery system issues a warning to the user by means of a sound alarm.

[0039] In one embodiment, the quantitative feeding mechanism includes a rotatable distributor, which is a powder roller with multiple axial grooves of equal size evenly distributed on the outer surface. The distributor is connected to its drive motor, and the distributor can rotate along its central axis under the drive of the drive motor, and when rotating, it transports the powder in the axial groove to the powder delivery pipeline. It should be noted that the present application does not limit the structure of the quantitative feeding mechanism. In other examples, the quantitative feeding mechanism may also include a valve with a timer switch, so that the quantitative feeding mechanism can achieve quantitative input of powder into the powder delivery pipeline by adjusting the switch time of the powder storage container.

[0040] It should be noted that the communication passage inside the powder storage device and / or the communication passage between the powder storage device and the powder delivery pipeline may be formed by a pipeline.

[0041] In one embodiment, the powder storage device is a device in the powder feeding device, for example, the powder feeding device is a movable powder feeding device or a powder feeding device fixed next to the 3D printing device. Furthermore, the powder feeding device also includes the first airflow generating device and part of the powder feeding pipeline mentioned above. In other words, the powder storage device in the powder feeding device is connected to the powder feeding pipeline through a pipeline to realize the transportation of powder to the powder feeding pipeline. In other embodiments, the powder storage device can also be directly arranged on the 3D printing device, for example, directly arranged at the bottom of the 3D printing device.

[0042] like Figure 1 and Figure 3 As shown, the first filter container 110 is arranged in the 3D printing device and connected to the powder delivery pipeline L1. The first filter container 110 includes a first cavity 1103 and a first powder inlet 1102 and a first gas outlet 1101 arranged on the first cavity 1103. The first filter container 110 is used to separate the powder and gas entering from the first powder inlet 1102, so as to discharge the gas from the first gas outlet 1101 to the powder delivery pipeline L1, and collect the powder in the first cavity 1103. In one example, the first gas outlet 1101 is arranged on the upper side of the first filter container 110, so as to facilitate the gas to be discharged from the first gas outlet 1101.

[0043] In one embodiment, the first filter container 110 is a cyclone filter container. When the gas and powder enter the cyclone filter container through the first powder inlet, the airflow starts to rotate due to the conical bottom of the cyclone filter container, thereby generating centrifugal force. Due to the centrifugal force, the heavier powder will be deposited in the first cavity of the cyclone filter container under the action of the centrifugal force, and the gas will be discharged from the first gas outlet on the upper side of the cyclone filter container.

[0044] In one embodiment, a first filter element 1100 is disposed in the first cavity 1103 of the first filter container 110, the first gas outlet 1101 is connected to the inner space of the first filter element 1100, and the first powder inlet 1102 is connected to the powder delivery pipeline L1 and the powder collection space outside the first filter element 1100 for collecting powder. Specifically, the first filter element 1100 can allow gas to enter its inner space, blocking solid powder in the powder collection space, and then, the first filter container 110 can use its first filter element 1100 to separate the gas and powder entering from the first powder inlet 1102, so that the gas is discharged from the first gas outlet 1101 to the powder delivery pipeline L1, and the powder is collected in the powder collection space of the first filter container 110. In a specific embodiment, the first filter container is a cyclone filter container, and a first filter element is disposed in the first cavity of the cyclone filter container.

[0045] like Figure 2 and Figure 4 As shown, the second filter container 111 is arranged in the 3D printing device and connected to the powder delivery pipeline L1 in parallel with the first filter container 110. The second filter container 111 includes a second cavity 1113 and a second powder inlet 1112 and a second gas outlet 1111 arranged on the second cavity 1113. The second filter container 111 is used to separate the powder and gas entering from the second powder inlet 1112, so as to discharge the gas from the second gas outlet 1111 to the powder delivery pipeline L1, and collect the powder in the second cavity 1113. In one example, the second gas outlet 1111 is arranged on the upper side of the second filter container 111, so as to facilitate the gas to be discharged from the second gas outlet 1111.

[0046] In one embodiment, the second filter container is a cyclone filter container. When the gas and powder enter the cyclone filter container through the second powder inlet, the airflow starts to rotate due to the conical bottom of the cyclone filter container, thereby generating centrifugal force. Due to the centrifugal force, the heavier powder will be deposited in the second cavity of the cyclone filter container under the action of the centrifugal force, and the gas will be discharged from the second gas outlet on the upper side of the cyclone filter container.

[0047] In one embodiment, a second filter element 1110 is disposed in the second cavity 1113 of the second filter container 111, the second gas outlet 1111 is connected to the inner space of the second filter element 1110, and the second powder inlet 1112 is connected to the powder delivery pipeline L1 and the powder collection space outside the second filter element 1110 for collecting powder. Specifically, the second filter element 1110 can allow gas to enter its inner space, blocking solid powder in the powder collection space, and then, the second filter container 111 can use its second filter element 1110 to separate the gas and powder entering from the second powder inlet 1112, so that the gas is discharged from the second gas outlet 1111 to the powder delivery pipeline L1, and the powder is collected in the powder collection space of the second filter container 111. In a specific embodiment, the second filter container is a cyclone filter container, and a second filter element is disposed in the second cavity of the cyclone filter container.

[0048] The pore sizes of the first filter element and the second filter element are both in the micron range to prevent powder from entering the inner space of the first filter element and the second filter element. In one embodiment, the pore sizes of the first filter element and the second filter element are both in the range of 0.1 micron to 10 microns. For example, the pore sizes of the first filter element and the second filter element are both 0.5 microns.

[0049] It should be noted that the powder collected in the powder collecting space of the first filter container or the second filter container does not necessarily have to be cached in the powder collecting space of the first filter container or the second filter container. In other embodiments, when feeding powder, the powder collecting space of the first filter container or the second filter container may also be continuously or intermittently connected to the powder cache bin in the 3D printing device. When the powder collecting space of the first filter container or the second filter container is connected to the powder cache bin, the powder may also directly enter the powder cache bin through the powder collecting space of the first filter container or the second filter container. The powder cache bin will be described in detail later.

[0050] The powder delivery system further includes a valve assembly, which includes a plurality of valves. The plurality of valves are respectively arranged on the passages between the powder delivery pipeline and the first filter container and the second filter container, and are used to switch the passages between the powder delivery pipeline and the first filter container and the second filter container. In other words, the first filter container and the second filter container do not perform the work of separating gas and powder at the same time. For example, when the first filter container is disconnected from the powder delivery pipeline and the second filter container is connected to the powder delivery pipeline, only the second filter container in the powder delivery system performs the work of separating gas and powder, and the passage between the powder delivery pipeline and the first filter container is closed by the valve assembly. For another example, when the second filter container is disconnected from the powder delivery pipeline and the first filter container is connected to the powder delivery pipeline, only the first filter container in the powder delivery system performs the work of separating gas and powder, and the passage between the powder delivery pipeline and the second filter container is closed by the valve assembly.

[0051] In one embodiment, if Figure 1 and Figure 2 As shown, the valve assembly 12 includes four valves (12a, 12b, 12c, and 12d). The valves 12a and 12b are arranged on the passage between the powder delivery pipeline L1 and the first filter container 110. When the valves 12a and 12b are opened, the powder delivery pipeline L1 is connected to the first filter container 110. When the valves 12a and 12b are closed, the powder delivery pipeline L1 is disconnected from the first filter container 110. The valves 12c and 12d are arranged on the passage between the powder delivery pipeline L1 and the second filter container 111. When the valves 12c and 12d are opened, the powder delivery pipeline L1 is connected to the second filter container 111. When the valves 12c and 12d are closed, the powder delivery pipeline L1 is disconnected from the second filter container 111. Specifically, as Figure 1 As shown, valves 12a and 12b are opened while valves 12c and 12d are closed. At this time, the powder delivery pipeline L1 is only connected to the first filter container 110, and the first filter container 110 can be used to separate the powder and the gas. Figure 2 As shown, valves 12c and 12d are opened while valves 12a and 12b are closed. At this time, the powder delivery pipeline L1 is only connected to the second filter container 111. At this time, the second filter container 111 can be used to separate powder and gas.

[0052] It should be noted that the present application only takes the example that the valve assembly includes four valves. In other embodiments, the number of valves in the valve assembly can also be two, and each valve is a three-way valve.

[0053] When the first filter element 1100 or the second filter element 1110 separates gas and powder for a long time, powder may adhere to the outer surface of the first filter element 1100 or the second filter element 1110 , thereby clogging the first filter element 1100 or the second filter element 1110 .

[0054] To this end, in one embodiment, Figure 1 and Figure 2 As shown, the powder delivery system further includes a first reverse blowing pipeline L2, the first reverse blowing pipeline L2 includes a first dust removal gas input port (not shown), the first dust removal gas input port is provided with a first gas source 20, the first gas source 20 can pass dust removal gas into the core space of the first filter element 1100 to remove the powder attached to the outer surface of the first filter element 1100, or pass dust removal gas into the core space of the second filter element 1110 to remove the powder attached to the outer surface of the second filter element 1110. The outer surfaces of the first filter element 100 and the second filter element 1110 are surfaces facing their respective powder collecting spaces.

[0055] In one specific embodiment, see Figure 2 Combined with Figure 4 , while the first gas source 20 is connected to the inner space of the first filter element 1100 and the first filter container 110 is disconnected from the powder delivery pipeline L1, the second filter container 111 is connected to the powder delivery pipeline L1. In other words, when the first filter element 1100 of the first filter container 110 is back-blown, the connection between the first filter container 110 and the powder delivery pipeline L1 is cut off, and the powder and gas are separated by the second filter container 111 in the powder delivery system. Specifically, when the first filter element 1100 is back-blown, the valve on the first back-blowing pipeline L2 that is connected to the first filter container 110 is opened, and the valve on the first back-blowing pipeline L2 that is connected to the second filter container 111 is closed. For example, Figure 2 The valves 210 and 212 in the valve assembly are both opened, the valves 211 and 213 are both closed, and the valves 12a and 12b in the valve assembly are closed and the valves 12c and 12d are opened at the same time.

[0056] In another specific embodiment, see Figure 1Combined with Figure 3 , while the first gas source 20 is connected to the inner space of the second filter element 1110 and the second filter container 111 is disconnected from the powder delivery pipeline L1, the first filter container 110 is connected to the powder delivery pipeline L1. In other words, when the second filter element 1110 of the second filter container 111 is back-blown, the connection between the second filter container 111 and the powder delivery pipeline L1 is cut off, and the powder and gas are separated by the first filter container 110 in the powder delivery system. Specifically, when the second filter element 1110 is back-blown, the valve on the first back-blowing pipeline L2 that is connected to the second filter container 111 is opened, and the valve on the first back-blowing pipeline L2 that is connected to the first filter container 110 is closed. For example, Figure 1 The valves 210 and 212 in the valve assembly are both closed, the valves 211 and 213 are both opened, and the valves 12a and 12b in the valve assembly are opened and the valves 12c and 12d are closed at the same time.

[0057] In one embodiment, the first reverse blowing pipeline further includes a first dust removal gas outlet, which is connected to a ventilation duct connected to the outside of the room. When the powder collecting space of the first filter container is connected to the first dust removal gas outlet, the dust removal gas in the first filter container is discharged to the outside of the room through the ventilation duct. When the powder collecting space of the second filter container is connected to the first dust removal gas outlet, the dust removal gas in the second filter container is discharged to the outside of the room through the ventilation duct. Figure 1 and Figure 2 As shown, the first reverse blowing pipeline L2 includes a first dust removal gas outlet (214a, 214b), and the first dust removal gas outlet (214a, 214b) is connected to the ventilation duct. Figure 1 As shown, when valves 210 and 212 are closed and valves 211 and 213 are open, the powder collecting space of the second filter container 111 is connected to the first dust removal gas outlet 214b, and the dust removal gas in the second filter container 111 is discharged through the ventilation duct. Figure 2 As shown, when valve 210 and valve 212 are both opened and valve 211 and valve 213 are both closed, the powder collecting space of the first filter container 110 is connected to the first dust removal gas output port 214a, and the dust removal gas in the first filter container 110 is discharged through the ventilation duct.

[0058] In order to ensure that the dust-removed gas does not carry powder with it and is discharged outdoors from the ventilation duct during back-blowing, a filter is provided between the ventilation duct and the second filter container 111 and / or between the ventilation duct and the first filter container 110. The filter on the first back-blowing pipeline is used to prevent powder from entering the ventilation duct. In one embodiment, the filter includes a filter element.

[0059] In one embodiment, the powder delivery system includes a timing device. The timing device is used to detect the time when the first filter container is connected to the powder delivery pipeline. After the time when the first filter container is connected to the powder delivery pipeline reaches a preset time, the first filter element may be blocked. At this time, the first gas source is connected to the inner space of the first filter element, and the first filter container is disconnected from the powder delivery pipeline, and the second filter container is connected to the powder delivery pipeline; in other words, after the time when the first filter container is connected to the powder delivery pipeline reaches a preset time, the first gas source back-blows the first filter element, and the second filter container separates the powder and the gas. It should be noted here that in order to distinguish it from other subsequent timing devices, in the embodiment, the timing device used to detect the time when the first filter container is connected to the powder delivery pipeline is also referred to as the first timing device.

[0060] In one embodiment, the powder delivery system includes a timing device. The timing device is a timing device for detecting the time when the second filter container is connected to the powder delivery pipeline. After the time when the second filter container is connected to the powder delivery pipeline reaches a preset time, the second filter element may be blocked, so at this time, the first gas source is connected to the core space of the second filter element and the second filter container is disconnected from the powder delivery pipeline, and the first filter container is connected to the powder delivery pipeline; in other words, after the time when the second filter container is connected to the powder delivery pipeline reaches a preset time, the first gas source back-blows the second filter element, and the first filter container separates the powder and the gas. It should be noted here that in order to distinguish it from other timing devices, in the embodiment, the timing device for detecting the time when the second filter container is connected to the powder delivery pipeline is also referred to as the second timing device.

[0061] It should be noted that the first timing device and the second timing device may be the same timing device or different timing devices. In the following embodiments, the first timing device and the second timing device are taken as the same timing device for example.

[0062] In one embodiment, the first timing device and the second timing device are exemplified as timers in the control system of the powder delivery system. For example, when the valves 12a and 12b in the powder delivery pipeline are opened by a control signal of the control system, the timer is started to detect the time when the first filter container is connected to the powder delivery pipeline. For another example, when the valves 12c and 12d in the powder delivery pipeline are opened by a control signal of the control system, the timer is started to detect the time when the second filter container is connected to the powder delivery pipeline.

[0063] In one embodiment, the powder feeding system includes a pressure detection device, such as Figure 1 and Figure 3 As shown, the pressure detection device includes a first differential pressure sensor 13a, which is connected to the powder collecting space and the inner core space of the first filter element 1100, and is used to measure the pressure difference between the powder collecting space and the inner core space of the first filter element 1100. After determining that the pressure difference is greater than the preset pressure difference, the first filter element 1100 may have a blockage problem. At this time, the first gas source 20 is connected to the inner core space of the first filter element 1100 and the first filter container 110 is disconnected from the powder delivery pipeline L1, and the second filter container 111 is connected to the powder delivery pipeline L1; in other words, after the pressure difference between the powder collecting space of the first filter element 1100 and the inner core space of the first filter element 1100 reaches the preset pressure difference, the first gas source 20 back-blows the first filter element 1100, and the second filter container 111 separates the powder and gas. For example, the communication path of the powder delivery gas is Figure 1 Switch to Figure 2 .

[0064] In one embodiment, the powder feeding system includes a pressure detection device, such as Figure 2 and Figure 4As shown, the pressure detection device includes a second differential pressure sensor 13b, for example, the pressure detection device includes the first differential pressure sensor 13a and the second differential pressure sensor 13b described above. The second differential pressure sensor 13b is connected to the powder collecting space of the second filter element 1110 and the inner space thereof, and is used to measure the pressure difference between the powder collecting space of the second filter element 1110 and the inner space thereof. After determining that the pressure difference is greater than the preset pressure difference, the second filter element 1110 may be blocked. At this time, the first gas source 20 is connected to the core space of the second filter element 1110, and the second filter container 111 is disconnected from the powder delivery pipeline L1, and the first filter container 110 is connected to the powder delivery pipeline L1; in other words, after the pressure difference between the powder collecting space of the second filter element 1110 and the core space of the second filter element 1110 reaches the preset pressure difference, the first gas source 20 back-blows the second filter element 1110, and the first filter container 110 separates the powder and the gas. For example, the communication path of the powder delivery gas is Figure 2 Switch to Figure 1 .

[0065] In other embodiments, the powder delivery system may also include a flow meter for detecting the pneumatic valve, and whether the first pneumatic valve or the second pneumatic valve has a blockage problem may be inferred based on the flow rate detected by the flow meter.

[0066] In one embodiment, if Figure 1 and Figure 2 As shown, a filter 14 is also provided in the powder delivery pipeline, and the filter 14 in the powder delivery pipeline is used to prevent powder from entering the first airflow generating device 18 through the air inlet of the first airflow generating device 18 (such as a fan). In this way, the influence of powder on the first airflow generating device 18 can be avoided. In one embodiment, the filter 14 includes a filter element.

[0067] In one embodiment, if Figure 1 and Figure 2 As shown, the powder delivery pipeline L1 is also provided with a temperature sensor 151, and the temperature sensor 151 is used to monitor the temperature in the powder delivery pipeline L1. When the control system of the powder delivery system determines that the temperature exceeds a preset temperature value, the powder delivery system is controlled to stop working to avoid explosion.

[0068] In one embodiment, if Figure 1 and Figure 2 As shown, the powder delivery pipeline L1 is also provided with a pressure sensor 152, and the pressure sensor 152 is used to monitor the pressure in the powder delivery pipeline L1. When the control system of the powder delivery system determines that the pressure exceeds a preset pressure value, the powder delivery system is controlled to stop working to avoid explosion.

[0069] In one embodiment, if Figure 1 and Figure 2 As shown, the powder feeding system also includes a powder buffer bin 16, which is arranged in the 3D printing device. The powder buffer bin 16 is used to receive the powder in the first filter container 110 and / or the second filter container 111 and supply the powder to the powder spreading device of the 3D printing device when communicating with the first filter container 110 and / or the second filter container 111, so that the powder spreading device can spread the powder on the component platform of the 3D printing device during printing. For example, a valve 17a is provided on the passage between the powder buffer bin 16 and the first filter container 110, and a valve 17b is provided on the passage between the powder buffer bin 16 and the second filter container 111. When powder needs to be delivered to the powder buffer bin 16, valve 17a and / or valve 17b can be opened. For example, valve 17a is opened and valve 17b is closed, and the powder buffer bin 16 is connected to the first filter container 110, and the powder buffer bin 16 receives the powder in the first filter container 110. For another example, when valve 17b is opened and valve 17a is closed, the powder buffer bin 16 is connected to the second filter container 111, and the powder buffer bin 16 can receive the powder in the second filter container 111. For another example, when valves 17a and 17b are both opened, the powder buffer bin 16 is connected to the first filter container 110 and the second filter container 111 at the same time, and the powder buffer bin 16 receives the powder in the first filter container 110 and the second filter container 111.

[0070] During the printing process of each layer of the 3D printing device, the amount of powder delivered from the powder buffer to the molding table is greater than the amount of powder required for printing the layer, and the excess powder will be collected in the powder recovery bucket of the 3D printing device, and after the printing is completed, powder will remain in the molding table of the 3D printing device. It should be noted that in order to distinguish it from the powder described above, in the embodiment, the powder in the powder recovery bucket and the powder remaining on the molding table are referred to as recovered powder.

[0071] In order to screen the recycled powder and convey the screened powder to the powder storage device of the 3D printing device, the powder feeding system also includes a powder screening device, which is connected to the powder storage device, and is used to screen the recycled powder on the forming table or the recycled powder in the powder recovery barrel and convey the screened powder to the powder storage device. Specifically, when screening the powder, the powder screening device is connected to the forming table or the powder recovery barrel, collects the recycled powder in the forming table or the powder recovery barrel, screens the recycled powder, and conveys the screened powder to the powder storage device. Then, after stopping the powder screening, the powder storage device conveys the collected impurity-free powder to the first filter container or the second filter container of the 3D printing device, and then the powder buffer in the 3D printing device can receive the powder in the first filter container and / or the second filter container.

[0072] In one embodiment, see Figure 6 and Figure 7 , Figure 6 It is a schematic diagram of the gas passage when the powder screening device screens the recovered powder on the forming table in one embodiment of the present application. Figure 7 The figure shows a schematic diagram of a gas circulation path when a powder screening device in one embodiment of the present application screens the recovered powder in the powder recovery barrel. As shown in the figure, the powder screening device includes a powder screening pipeline L4, a third filter container 40, a screening mechanism 46, and a waste collection barrel 42. Specifically, the powder screening pipeline L4 is used to convey the recovered powder on the forming table 60 or the recovered powder in the powder recovery barrel 61 through the airflow in the pipeline. The third filter container 40 is connected to the powder screening pipeline L4, and the third filter container 40 includes a third cavity 403, and a third powder inlet 402 and a third gas outlet 401 arranged on the third cavity 403. The third filter container 40 is used to separate the recovered powder and gas entering from the third powder inlet 402, so as to discharge the gas from the third gas outlet 401 to the powder screening pipeline L4, and collect the recovered powder in the third cavity 403. The screening mechanism 46 is connected to the third filter container 40 to receive the recovered powder in the third cavity 403, and then the screening mechanism 46 screens the recovered powder to transport the screened powder to the powder storage device 10. The waste collection cylinder 42 is connected to the screening mechanism 46 to collect impurities screened by the screening mechanism 46.

[0073] In one embodiment, if Figure 6As shown, when the powder screening pipeline L4 is used to transport the recycled powder on the molding table 60, the recycled powder input end of the powder screening pipeline L4 is connected to the molding table 60 to collect the recycled powder from the molding table 60, and the gas output end of the powder screening pipeline L4 is connected to the ventilation duct connected to the outside of the room. In this embodiment, the powder screening pipeline L4 is a non-closed pipeline. For example, the powder screening pipeline L4 is the pipeline shown by the dotted line.

[0074] In one embodiment, if Figure 7 As shown, when the powder screening pipeline L4 is used to transport the recovered powder in the powder recovery barrel 61, the powder screening pipeline L4 is a closed pipeline, and the powder recovery barrel 61 is arranged on the powder screening pipeline L4.

[0075] In one embodiment, the powder screening pipeline and the powder delivery pipeline include a common pipeline, and the powder delivery system further includes valves respectively arranged at both ends of the common pipeline, and the valves arranged at both ends of the common pipeline are used to switch the passage between the common pipeline and the remaining pipeline in the powder screening pipeline after removing the common pipeline and the remaining pipeline in the powder delivery pipeline after removing the common pipeline. Figure 6 and Figure 7 As shown, valves 43a and 43b are respectively provided at both ends of the common pipeline. When the powder feeding system screens and recovers the powder, valves 43a and 43b are closed at the same time, and the common pipeline is connected with the remaining pipeline in the powder screening pipeline except the common pipeline, and the common pipeline is disconnected from the communication passage with the remaining pipeline in the powder feeding pipeline except the common pipeline, thereby Figure 6 and Figure 7 The powder screening pipeline described by the dotted line is in a connected state. When the powder feeding system stops screening and recovering powder, valve 43a and valve 43b are opened at the same time, the common pipeline is disconnected from the connection passage of the remaining pipeline in the powder screening pipeline except the common pipeline, and the common pipeline is connected with the remaining pipeline in the powder feeding pipeline except the common pipeline, so as to feed powder to the 3D printing device through the powder feeding pipeline. In one embodiment, the valve 43a and valve 43b can be two-way valves or three-way valves. For example, Figure 6 When the powder screening pipeline L4 is a non-closed pipeline, the valve 43b is a three-way valve, and the valve 43a is a two-way valve.

[0076] The airflow in the powder screening pipeline is generated by a second airflow generating device connected to the powder screening pipeline. For example, the second airflow generating device may be a fan or a vacuum pump. The second airflow generating device and the first airflow generating device described above may be the same airflow generating device or different airflow generating devices. In the following embodiments, the second airflow generating device and the first airflow generating device are taken as an example to be the same airflow generating device.

[0077] The airflow generated by the second airflow generating device drives the recovered powder to move in the powder screening pipeline L4 , so that the powder screening pipeline L4 transports the recovered powder and gas to the third filtering container 40 .

[0078] In one embodiment, the third filter container 40 is a cyclone filter container. When the gas and the recovered powder enter the cyclone filter container through the third powder inlet 402, the airflow starts to rotate due to the conical bottom of the cyclone filter container, thereby generating centrifugal force. Due to the centrifugal force, the heavier recovered powder will be deposited in the third cavity 403 of the cyclone filter container under the action of the centrifugal force, and the gas will be discharged from the third gas outlet 401 on the upper side of the cyclone filter container.

[0079] In one embodiment, a third filter element 400 is disposed in the third cavity 403 of the third filter container 40, the third gas outlet 401 is connected to the inner space of the third filter element 400, and the third powder inlet 402 is connected to the powder screening pipeline L4 and the powder collecting space outside the third filter element 400. Specifically, the third filter element 400 can allow gas to enter its inner space and block solid recovered powder in the powder collecting space. Then, the third filter container 40 can use its third filter element 400 to separate the gas and recovered powder entering from the third powder inlet 402, so that the gas is discharged from the third gas outlet 401 to the powder screening pipeline L4, and the recovered powder is collected in the powder collecting space of the third filter container 40. In a specific embodiment, the third filter container is a cyclone filter container, and a third filter element is disposed in the third cavity of the third filter container.

[0080] In one embodiment, if Figure 6 As shown, the powder delivery system also includes a second reverse blowing pipeline L5, the second reverse blowing pipeline L5 includes a second dust removal gas input port, and the second dust removal gas input port is provided with a third gas source 50, and the third gas source 50 is used to pass dust removal gas into the core space of the third filter element 400 to remove the powder attached to the outer surface of the third filter element 400. Among them, the outer surface of the third filter element 400 is the surface facing the powder collecting space of the third filter element. When the third gas source 50 is reverse blowing, it is necessary to cut off the communication path between the third filter container 40 and the powder screening pipeline L4, and connect the third filter container 40 with the second reverse blowing pipeline L5.

[0081] In one embodiment, see Figure 8 and Fig. 9 , Figure 8 It is a schematic diagram showing that the third filter container in the powder screening device in one embodiment of the present application is connected with the powder delivery pipeline, Fig. 9The schematic diagram of the fourth filter container in the powder screening device in one embodiment of the present application being connected to the powder delivery pipeline is shown. As shown in the figure, the powder screening device further includes a fourth filter container 41 connected in parallel with the third filter container 40 on the powder screening pipeline L4. Fig. 9 As shown, the fourth filter container 41 includes a fourth cavity 413, and a fourth powder inlet 412 and a fourth gas outlet 411 arranged on the fourth cavity 413. The fourth filter container 41 is used to separate the recovered powder and gas entering from the fourth powder inlet 412, and discharge the gas from the fourth gas outlet 411 to the powder screening pipeline L4, and collect the recovered powder in the fourth cavity 413.

[0082] In one embodiment, if Fig. 9 As shown, a fourth filter element 410 is disposed in the fourth cavity 413 of the fourth filter container 41, the fourth gas outlet 411 is connected to the inner core space of the fourth filter element 410, and the fourth powder inlet 412 is connected to the powder screening pipeline L4 and the powder collecting space outside the fourth filter element 410. Specifically, the fourth filter element 410 can allow gas to enter its inner core space, blocking solid recovered powder in the powder collecting space, and then, the fourth filter container 41 can use its fourth filter element 410 to separate the gas entering from the fourth powder inlet 412 from the recovered powder, so that the gas is discharged from the fourth gas outlet 411 to the powder screening pipeline L4, and the recovered powder is collected in the powder collecting space of the fourth filter container 41. In a specific embodiment, the fourth filter container is a cyclone filter container, and a fourth filter element is disposed in the fourth cavity of the fourth filter container.

[0083] Furthermore, the powder screening device further includes a plurality of valves arranged on the passages between the powder screening pipeline and the third filter container and the fourth filter container, and the plurality of valves on the powder screening pipeline are used to switch the passages between the powder screening pipeline and the third filter container and the fourth filter container. In other words, the third filter container and the fourth filter container do not perform the work of separating gas and recovering powder at the same time. For example, when the third filter container is disconnected from the powder screening pipeline and the communication passage is disconnected, the fourth filter container is connected to the powder screening pipeline, and only the fourth filter container in the powder delivery system performs the work of separating gas and recovering powder, and the passage between the powder screening pipeline and the third filter container is closed by the valve. For another example, when the fourth filter container is disconnected from the powder screening pipeline and the communication passage is disconnected, the third filter container is connected to the powder screening pipeline, and only the third filter container in the powder delivery system performs the work of separating gas and recovering powder, and the passage between the powder screening pipeline and the fourth filter container is closed by the valve.

[0084] In one embodiment, when valves 45a and 45b are opened, the powder screening pipeline L4 is connected to the third filter container 40, and when valves 45a and 45b are closed, the powder screening pipeline L4 is disconnected from the third filter container 40. Valves 45c and 45d are arranged on the passage between the powder screening pipeline L4 and the fourth filter container 41, and when valves 45c and 45d are opened, the powder screening pipeline L4 is connected to the fourth filter container 41, and when valves 45c and 45d are closed, the powder screening pipeline L4 is disconnected from the fourth filter container 41. Specifically, Figure 8 As shown, valves 45a and 45b are opened while valves 45c and 45d are closed. At this time, the powder screening pipeline L4 is only connected to the third filter container 40. At this time, the third filter container 40 can be used to separate the recovered powder and gas. Fig. 9 As shown, valves 45a and 45b are closed while valves 45c and 45d are opened. At this time, the powder screening pipeline L4 is only connected to the fourth filter container 41. At this time, the fourth filter container 41 can be used to separate the recovered powder and gas.

[0085] Furthermore, when the powder screening device further includes a fourth filter container, the second back-blowing pipeline may also be connected to the fourth filter container 41, so as to back-blow the fourth filter container when the fourth filter container may be blocked. It should be noted that the manner and timing of back-blowing the fourth filter container or the third filter container by the second back-blowing pipeline are the same or similar to the manner and timing of back-blowing the first filter container or the second filter container by the first back-blowing pipeline, and will not be described in detail here.

[0086] In one embodiment, if Figure 6 and Figure 7 As shown, the screening mechanism 46 is connected to the third filtering container 40, and the screening mechanism 46 is used to screen the recovered powder and transport the screened powder to the powder storage device 10. In another embodiment, as Figure 8 and Fig. 9 As shown, when the powder screening device includes a fourth filtering container 41 , the screening mechanism 46 can also be connected to the fourth filtering container 41 .

[0087] The sieved powder is the powder after the impurities in the recycled powder are removed. In one embodiment, the screening mechanism 46 includes a vibrating screening mechanism. For example, the screening mechanism includes a vibrating device and a screen, and the vibrating device is used to cause the screen to vibrate so as to discharge larger particles of impurities into the waste collection bucket 42, and the powder after the impurities are removed passes through the screen into the powder storage device 10. The vibrating device is exemplified by a vibration motor or an ultrasonic system.

[0088] In one embodiment, the waste collecting barrel 42 is in communication with the screening mechanism 46 , and the waste collecting barrel 42 is used to collect impurities screened out by the screening mechanism 46 .

[0089] In one embodiment, the powder delivery system further includes a control system, and the control system of the powder delivery system is used to control the operation of various devices in the powder delivery system, such as controlling the operation of devices such as temperature sensors, pressure sensors, oxygen content sensors, or airflow generating devices in the powder delivery system. The control system of the powder delivery system is also used to control the closing and opening of various valves in the system, and the opening and closing of the first gas source, the second gas source, or the third gas source. In one embodiment, the control system includes a memory and a processor. Further, the control system also includes a plurality of interface units.

[0090] It should be noted that the present application does not limit the physical locations of various valves, pipelines, gas sources, and various devices in the powder delivery system. For example, the first filter container, the second filter container, and the powder buffer bin of the powder delivery system can be located in the 3D printing device, and the various valves of the powder delivery system can all be located in an independent powder delivery device, or the various valves of the powder delivery system can also be partially located in an independent powder delivery device and partially located in the 3D printing device, or the various valves of the powder delivery system can also all be located in the 3D printing device. In one embodiment, the independent powder delivery device includes a first airflow generating device and a powder storage device in the powder delivery system.

[0091] The present application also provides a 3D printing device, which includes a molding table, a first filtering container, a second filtering container, an optical system, and a control device.

[0092] The entire printing operation of the 3D printing device is performed in a molding chamber protected by an inert gas to prevent the powder from oxidizing at high temperatures. A molding table is provided in the molding chamber of the 3D printing device, and the entire printing operation of the 3D printing device can be performed on the molding table. For example, the 3D printing device performs a powder spreading operation on the molding table. For another example, the 3D printing device prints a 3D object on the molding table.

[0093] The forming table includes a forming table body and a forming groove. The forming table body can be detachably fixed to the inner wall of the forming chamber by various suitable devices (such as screws, buckles, etc.).

[0094] In one embodiment, the molding groove is provided on the molding platform body, the opening of the molding groove faces the optical system, and is used to accommodate the powder. In some embodiments, the molding groove may be in the shape of a cube, a cuboid, or other shapes.

[0095] The molding tank is provided with a component platform and a Z-axis driving mechanism, and the component platform is used to attach the 3D object which is solidified layer by layer by the optical system. The component platform is closely attached to the inner wall of the molding tank, and during the printing process, it moves layer by layer in the vertical direction under the drive of the Z-axis driving mechanism.

[0096] In one embodiment, the component platform includes a component plate and a mounting assembly detachably connected to the component plate, the upper surface of the component plate is used to attach a 3D object that is solidified layer by layer through irradiation by the optical system, and the lower surface of the component plate is detachably connected to the mounting assembly. When the printing job is completed, the staff can separate the component plate from the mounting assembly to take out the component plate and the 3D object attached thereto, and then perform post-processing operations on the 3D object (for example, cutting, support removal, polishing, grinding or sandblasting, etc.).

[0097] The Z-axis driving mechanism is connected to the component platform and is used to controllably move in the vertical direction (Z-axis direction) to adjust the distance between the component platform and the printing reference surface. The control device controls the Z-axis driving mechanism to adjust the distance between the component platform and the printing reference surface according to the thickness of each layer printed, that is, to adjust the height of the molding area. The molding 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 object during the printing process.

[0098] In one embodiment, the Z-axis drive mechanism is directly connected to the mounting assembly of the component platform to adjust the distance between the component platform and the printing reference surface. In another embodiment, when the component platform includes the sealing assembly, the Z-axis drive mechanism is connected to the bottom plate on the lower side of the mounting assembly to adjust the distance between the component platform and the printing reference surface.

[0099] Specifically, 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 platform 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 platform 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 on the component platform 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 platform. The positioning and moving structure can be, for example, a ball screw.

[0100] In one embodiment, the molding table further includes a recycling groove. The recycling groove is provided on the side of the molding table body. For example, after the powder spreading device of the 3D printing device completes the powder spreading operation, the remaining powder is pushed into the recycling groove, and then the powder in the recycling groove can be collected into the powder recovery barrel mentioned above.

[0101] The first filter container is arranged in the 3D printing device and connected to the powder delivery pipeline. The first filter container includes a first cavity, and a first powder inlet and a first gas outlet arranged on the first cavity. The first filter container is used to separate the powder and gas entering from the first powder inlet, so as to discharge the gas from the first gas outlet to the powder delivery pipeline and collect the powder in the first cavity.

[0102] The second filter container is arranged in the 3D printing device and connected to the powder delivery pipeline in parallel with the first filter container. The second filter container includes a second cavity, and a second powder inlet and a second gas outlet arranged on the second cavity. The second filter container is used to separate the powder and gas entering from the second powder inlet, so as to discharge the gas from the second gas outlet to the powder delivery pipeline and collect the powder in the second cavity. The passages between the powder delivery pipeline and the first filter container and the second filter container can be switched by a plurality of valves respectively arranged on the passages between the powder delivery pipeline and the first filter container and the second filter container.

[0103] The working principles of the first filter container and the second filter container in the 3D printing device and the switching between the two and the powder delivery pipeline are the same or similar to those described above and will not be repeated here.

[0104] In one embodiment, the 3D printing device also includes a powder buffer bin for receiving powder in the first filter container and / or the second filter container. The powder buffer bin can supply the powder to the powder spreading device of the 3D printing device, so that the powder spreading device can spread the powder supplied by the powder buffer bin on the component platform, and can push the remaining powder into the recovery trough mentioned above.

[0105] The optical system is arranged above the molding chamber, and is used for emitting a light beam to irradiate the powder in the molding area of ​​the molding groove.

[0106] 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 preset intensity. The light source may be a laser, such as a fiber laser, a YAG laser, etc. The choice of light source is related to different types of printing equipment. For example, if an SLM-type 3D printing device needs to melt metal, the light source may be a high-power density light laser. The scanning galvanometer can be deflected when driven by its drive motor. For example, the drive motor of the scanning galvanometer is controlled by a control instruction output by the control device. The propagation direction of the light beam is adjusted by adjusting the deflection angle of the scanning galvanometer to accurately position the light beam to any position on the printing reference surface. Among them, the control instruction includes: a directional instruction for indicating the rotation or stop of the scanning galvanometer, and may even include parameters such as rotation speed / speed acceleration.

[0107] In a specific embodiment, the optical system includes a light source, a beam expander, a scanning galvanometer, an F-θ scanning lens, and a protective mirror. The light beam emitted by the light source first passes through the beam expander. After passing through the beam expander, the diameter of the light beam is enlarged, the divergence angle of the light beam is reduced, and the energy loss is reduced; after the light beam passes through the beam expander and reaches the scanning galvanometer, the scanning galvanometer controls the propagation direction of the light beam; the F-θ scanning lens is arranged at the lower side of the scanning galvanometer to converge the deflected light beam so that the light beam forms a focusing spot at any position on the printing reference surface, and the F-θ scanning lens can also avoid optical distortion; the protective mirror is arranged below the F-θ scanning lens, and the light beam finally passes through the protective mirror to reach the printing reference surface. The protective mirror is used to isolate the molding groove from optical devices such as the light source, the beam expander, the galvanometer, and the F-θ scanning lens to prevent dust from affecting the optical devices.

[0108] In one embodiment, the number of the optical systems is one or more. For example, when there are multiple optical systems, that is, when the number of the light source, the beam expander, the scanning galvanometer, the F-θ scanning lens, and the protective mirror is multiple, the multiple optical systems are arranged in parallel above the molding groove along the powder spreading direction, which can increase the area of ​​the molding area, thereby printing and realizing large-size 3D objects.

[0109] The control device is connected to the Z-axis drive mechanism and the optical system, and is used to control the optical system to irradiate the powder in the molding area, and to control the Z-axis drive mechanism to move vertically during printing operations, so as to attach a deposited pattern solidified layer on the component platform to obtain a corresponding 3D object. Specifically, the control device is electrically connected to the drive motor of the Z-axis drive mechanism, so that the Z-axis drive mechanism moves vertically to attach a deposited pattern solidified layer on the component platform to obtain a corresponding 3D object; the control device is electrically connected to the drive motor and light source of the galvanometer of the optical system, so that the optical system emits a light beam of a preset intensity at a preset angle.

[0110] The control device is an electronic device including a processor, for example, the control device is a computer device, an embedded device, or an integrated circuit with an integrated CPU, such as a control board or a main control board.

[0111] 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 the 3D printing device such as an optical system and a Z-axis drive mechanism 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.

[0112] For example, the interface unit includes: a USB interface, an HDMI interface and an RS232 interface, wherein there are multiple USB interfaces and RS232 interfaces, the USB interface can be connected to a human-computer interaction device, etc., the RS232 interface is connected to a Z-axis drive mechanism, and the HDMI interface is connected to an optical system. The storage unit is used to store files required for printing by the 3D printing device. The files include: program files and configuration files required for CPU operation, etc.

[0113] The storage unit includes a non-volatile memory and a system bus. The non-volatile memory is, for example, a solid state drive or a USB flash drive. The system bus is used to connect the non-volatile memory with the CPU, wherein the CPU can be integrated in the storage unit, or packaged separately from the storage unit and connected to the non-volatile memory through the system bus.

[0114] The processing unit includes: at least one of a CPU or a chip integrated with a CPU, a field programmable logic device (FPGA), and a multi-core processor. The processing unit also includes a memory, a register, and other storage devices for temporarily storing data.

[0115] In summary, the powder feeding system and 3D printing device provided by the present application, by arranging a first filter container and a second filter container in the 3D printing device, connecting the first filter container and the second filter container in parallel in a powder feeding pipeline, and arranging a valve assembly for switching the passages between the powder feeding pipeline and the first filter container and the second filter container, can enable the powder feeding system to use one of the filter containers to feed powder to the 3D printing device. If the filter container is blocked or needs to be cut off from the powder feeding pipeline, the valve assembly can be used to switch the powder feeding pipeline to another filter container, thereby avoiding stopping the fan and frequent air washing during the powder feeding process, thereby improving the powder feeding efficiency and safety.

[0116] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art 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 feeding system for feeding powder to a 3D printing device, characterized in that: include: A powder delivery pipeline, used for conveying powder in the pipeline through an input air flow; A powder storage device, arranged on the powder delivery pipeline, for delivering the stored powder to the powder delivery pipeline; a first filtering container, arranged in the 3D printing device and connected to the powder delivery pipeline, comprising a first cavity, and a first powder inlet and a first gas outlet arranged on the first cavity, for separating powder and gas entering from the first powder inlet, so as to discharge the gas from the first gas outlet to the powder delivery pipeline, and collect the powder in the first cavity; A second filter container is disposed in the 3D printing device and connected to the powder delivery pipeline in parallel with the first filter container, comprising a second cavity, and a second powder inlet and a second gas outlet disposed on the second cavity, for separating powder and gas entering from the second powder inlet, discharging the gas from the second gas outlet to the powder delivery pipeline, and collecting the powder in the second cavity; The valve assembly includes a plurality of valves, which are respectively arranged on the passages between the powder delivery pipeline and the first filter container and the second filter container, and are used for switching the passages between the powder delivery pipeline and the first filter container and the second filter container.

2. The powder feeding system according to claim 1, characterized in that: When the first filter container and the powder delivery pipeline are disconnected from each other, the second filter container is connected to the powder delivery pipeline.

3. The powder feeding system according to claim 1, characterized in that: When the second filter container is disconnected from the powder delivery pipeline, the first filter container is connected to the powder delivery pipeline.

4. The powder feeding system according to claim 1, characterized in that: The first filter container and the second filter container are cyclone filter containers.

5. The powder feeding system according to claim 1, characterized in that: A first filter element is arranged in the first cavity, the first gas outlet is connected to the core space of the first filter element, and the first powder inlet is connected to the powder delivery pipeline and the powder collecting space outside the first filter element for collecting powder; a second filter element is arranged in the second cavity, the second gas outlet is connected to the core space of the second filter element, and the second powder inlet is connected to the powder delivery pipeline and the powder collecting space outside the second filter element for collecting powder.

6. The powder feeding system according to claim 5, characterized in that: The powder delivery system also includes a first reverse blowing pipeline, which includes a first dust removal gas input port, and the first dust removal gas input port is provided with a first gas source, and the first gas source passes dust removal gas into the core space of the first filter element to remove powder attached to the outer surface of the first filter element, or the first gas source passes dust removal gas into the core space of the second filter element to remove powder attached to the outer surface of the second filter element.

7. The powder feeding system according to claim 6, characterized in that: The first reverse blowing pipeline also includes a first dust removal gas outlet, which is connected to a ventilation duct outside the room. When the powder collecting space of the first filter container is connected to the first dust removal gas outlet, the dust removal gas in the first filter container is discharged through the ventilation duct. When the powder collecting space of the second filter container is connected to the first dust removal gas outlet, the dust removal gas in the second filter container is discharged through the ventilation duct.

8. The powder feeding system according to claim 5, characterized in that: The powder delivery system further comprises a timing device for detecting the time when the first filter container is connected to the powder delivery pipeline.

9. The powder feeding system according to claim 5, characterized in that: The powder delivery system further comprises a timing device for detecting the time when the second filter container is connected to the powder delivery pipeline.

10. The powder feeding system according to claim 5, characterized in that: The powder feeding system further comprises a pressure detection device for detecting a pressure difference between the powder collecting space of the first filter element and the inner space of the first filter element.

11. The powder feeding system according to claim 5, characterized in that: The powder feeding system further comprises a pressure detection device for detecting the pressure difference between the powder collecting space of the second filter element and the inner space of the first filter element.

12. The powder feeding system according to claim 10 or 11, characterized in that: The pressure detection device includes a first differential pressure sensor and a second differential pressure sensor. The first differential pressure sensor is connected to the powder collecting space of the first filter element and the space inside the core, and is used to measure the pressure difference between the powder collecting space of the first filter element and the space inside the core. The second differential pressure sensor is connected to the powder collecting space of the second filter element and the space inside the core, and is used to measure the pressure difference between the powder collecting space of the second filter element and the space inside the core.

13. The powder feeding system according to claim 1, characterized in that: The powder delivery system also includes a pre-filling pipeline, on which a second gas source is provided. When the pre-filling pipeline is connected to the powder delivery pipeline and the second gas source is started, the second gas source pre-fills the powder delivery pipeline with inert gas through the pre-filling pipeline.

14. The powder feeding system according to claim 1, characterized in that: The powder feeding system also includes a powder buffer bin, which is arranged in the 3D printing device and is used to receive the powder in the first filter container and / or the second filter container and supply the powder to the powder spreading device of the 3D printing device when connected to the first filter container and / or the second filter container.

15. The powder feeding system according to claim 1, characterized in that: The powder delivery pipeline is a closed pipeline.

16. The powder feeding system according to claim 1, characterized in that: The powder delivery pipeline is also provided with at least one of a filter, a temperature sensor, a pressure sensor, and an oxygen content sensor.

17. The powder feeding system according to claim 1, characterized in that: The powder storage device comprises a powder storage container and a quantitative feeding mechanism, wherein the quantitative feeding mechanism is connected to the powder storage container and is used for quantitatively inputting the powder in the powder storage container into the powder delivery pipeline.

18. The powder feeding system according to claim 1, characterized in that: The powder feeding system also includes a powder screening device, which is connected to the powder storage device and is used to screen the recovered powder on the forming table or the recovered powder in the powder recovery barrel and transport the screened powder to the powder storage device.

19. The powder feeding system according to claim 18, characterized in that: The powder screening device comprises: A powder screening pipeline is used to convey the recovered powder on the forming table or the recovered powder in the powder recovery barrel through the airflow in the pipeline; a third filtering container, connected to the powder screening pipeline, comprising a third cavity, and a third powder inlet and a third gas outlet arranged on the third cavity, for separating the recovered powder and gas entering from the third powder inlet, so as to discharge the gas from the third gas outlet to the powder screening pipeline, and collect the recovered powder in the third cavity; A screening mechanism, connected to the third filter container, for screening and recovering powder materials, so as to transport the screened powder materials to the powder storage device; The waste collection cylinder is connected to the screening mechanism and is used to collect impurities screened by the screening mechanism.

20. The powder feeding system according to claim 19, characterized in that: The powder screening device also includes a fourth filter container connected to the powder screening pipeline and connected in parallel with the third filter container, the fourth filter container includes a fourth cavity, and a fourth powder inlet and a fourth gas outlet arranged on the fourth cavity, for separating the recovered powder and gas entering from the fourth powder inlet, so as to discharge the gas from the fourth gas outlet to the powder screening pipeline, and collect the recovered powder in the fourth cavity.

21. The powder feeding system according to claim 20, characterized in that: A third filter element is arranged in the third cavity, the third gas outlet is connected to the inner space of the third filter element, and the third powder inlet is connected to the powder screening pipeline and the powder collecting space outside the third filter element; a fourth filter element is arranged in the fourth cavity, the fourth gas outlet is connected to the inner space of the fourth filter element, and the fourth powder inlet is connected to the powder screening pipeline and the powder collecting space outside the fourth filter element.

22. The powder feeding system according to claim 21, characterized in that: The powder delivery system also includes a second back-blowing pipeline, the second back-blowing pipeline includes a second dust removal gas input port, the second dust removal gas input port is provided with a third gas source, the third gas source passes dust removal gas into the core space of the third filter element to remove powder attached to the outer surface of the third filter element, or the third gas source passes dust removal gas into the core space of the fourth filter element to remove powder attached to the outer surface of the fourth filter element.

23. The powder feeding system according to claim 19, characterized in that: When the powder screening pipeline is used to transport the recycled powder on the forming table, the recycled powder input end of the powder screening pipeline is connected to the forming table to collect the recycled powder from the forming table, and the gas output end of the powder screening pipeline is connected to the ventilation duct connected to the outside of the room.

24. The powder feeding system according to claim 19, characterized in that: When the powder screening pipeline is used to transport the recovered powder in the powder recovery barrel, the powder screening pipeline is a closed pipeline, and the powder recovery barrel is arranged on the powder screening pipeline.

25. The powder feeding system according to claim 19, characterized in that: The powder screening pipeline and the powder delivery pipeline include a common pipeline, and the powder delivery system also includes valves respectively arranged at both ends of the common pipeline, and the valves arranged at both ends of the common pipeline are used to switch the passage between the common pipeline and the remaining pipeline in the powder screening pipeline after removing the common pipeline and the remaining pipeline in the powder delivery pipeline after removing the common pipeline.

26. A 3D printing device, characterized in that: include: A molding table, arranged in a molding chamber of the 3D printing device, the molding table comprising a molding table body and a molding tank; A component platform and a Z-axis driving mechanism are arranged in the molding tank, the component platform is used to attach the 3D object that is solidified layer by layer by the optical system, and the Z-axis driving mechanism is connected to the component platform and is used to controllably move vertically to adjust the distance between the component platform and the printing reference surface; a first filtering container, arranged in the 3D printing device and connected to the powder delivery pipeline, comprising a first cavity, and a first powder inlet and a first gas outlet arranged on the first cavity, for separating powder and gas entering from the first powder inlet, so as to discharge the gas from the first gas outlet to the powder delivery pipeline, and collect the powder in the first cavity; A second filter container is arranged in the 3D printing device and connected to the powder delivery pipeline in parallel with the first filter container, comprising a second cavity, and a second powder inlet and a second gas outlet arranged on the second cavity, for separating powder and gas entering from the second powder inlet, so as to discharge the gas from the second gas outlet to the powder delivery pipeline, and collect the powder in the second cavity; wherein the passages between the powder delivery pipeline and the first filter container and the second filter container can be switched by a plurality of valves respectively arranged on the passages between the powder delivery pipeline and the first filter container and the second filter container; An optical system for emitting a light beam to illuminate the powder in the forming area of ​​the forming tank; A control device is connected to the optical system and the Z-axis drive mechanism, and is used to control the optical system to irradiate the powder in the molding area during the printing operation, and to control the Z-axis drive mechanism to move vertically during the printing operation, so as to attach and deposit the pattern solidified layer on the component platform to obtain the corresponding 3D object.

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