Additive manufacturing apparatus and method of swashing

Abstract

The invention relates to an additive manufacturing apparatus and a gas scrubbing method. The apparatus comprises: a forming chamber (11); a beam unit (15) configured to control a beam (152) to scan the powder layer by layer in the forming chamber (11) to build an object during a build phase; at least one layer of barrier (110) movably constructed within the forming chamber (11) and configured to divide at least a portion of the forming chamber (11) into an initial space (111) to be scrubbed during a scrubbing phase; and the gas supply unit (16) is configured to fill the initial space (111) with cleaning gas (160) and control the cleaning gas (160) to gradually expand from the initial space (111) to the target space (112) so as to improve the gas flow uniformity and the gas washing efficiency in the gas washing process.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing technology, and more particularly to an additive manufacturing apparatus and a purging method. Background Art

[0002] Additive manufacturing (also known as 3D printing) uses the principle of layer-by-layer construction to manufacture complex components, and its manufacturing process has high requirements for the environmental atmosphere inside the apparatus. For example, when using a powder bed-based additive manufacturing apparatus to construct an object, in order to make the chemical reaction and heat transfer processes during the construction process in an optimal state, it is usually necessary to maintain a specific atmosphere environment in the forming chamber. This requires purging the forming chamber before constructing the object, that is, by introducing a cleaning gas to displace the original air in the forming chamber to reduce the content of harmful substances such as oxygen and moisture, and to ensure the stability of the object construction process.

[0003] However, traditional purging methods usually perform overall purging on the entire forming chamber. However, due to the large volume of the forming chamber, uneven air flow is likely to occur during the purging process, resulting in incomplete displacement of impurity gases in some areas, thereby affecting the stability of the construction process. In addition, since overall purging takes a long time, it increases the waiting period of the apparatus and reduces the production efficiency. Summary of the Invention

[0004] This application relates to an additive manufacturing apparatus and a purging method to solve at least one of the above-described or un-described defects.

[0005] In a first aspect of this application, there is provided an additive manufacturing apparatus, including: a forming chamber; a beam unit configured to control a beam to scan powder layer by layer in the forming chamber during a construction stage to construct an object; at least one layer of barrier movably configured in the forming chamber and configured to divide at least a part of the forming chamber into an initial space to be purged during a purging stage; and a gas supply unit configured to fill the initial space with a cleaning gas and control the cleaning gas to gradually expand from the initial space to a target space.

[0006] According to a preferred embodiment of the first aspect, the gas supply unit is further configured to control the cleaning gas to gradually expand from the initial space to the target space as the at least one layer of barrier moves, wherein the volume of the initial space is not less than the minimum volume that enables the cleaning gas to enter.

[0007] According to a preferred embodiment of the first aspect, the movement of the at least one layer of barrier during the purging stage is driven by a pressure difference formed by continuously filling the initial space with the cleaning gas.

[0008] According to a preferred embodiment of the first aspect, the device further comprises: a gas monitoring unit configured to monitor in real time the amount of gas charged in the initial space; and a moving unit configured to drive the at least one layer of barrier to move when it is detected that the amount of gas charged in the initial space reaches a preset threshold, so as to transform the initial space into a target space.

[0009] According to a preferred embodiment of the first aspect, the at least one layer of barrier is constructed horizontally in the forming chamber and is provided with a notch; a hatch is provided at the top of the forming chamber, and the hatch and the notch correspond to each other in the vertical direction; the beam unit can be docked with the notch through the hatch to construct the target space below the at least one layer of barrier.

[0010] According to a preferred embodiment of the first aspect, the expansion rate of the initial space into the target space is 0.

[0011] According to a preferred embodiment of the first aspect, the at least one layer of barrier has a first barrier and a second barrier located below the first barrier, the notch is provided on the first barrier, the second barrier is configured to divide at least a part of the space below the first barrier into an initial space during the gas washing stage, and the gas supply unit is further configured to control the cleaning gas to gradually expand from the initial space to the target space as the second barrier moves.

[0012] According to a preferred embodiment of the first aspect, the at least one layer of barrier is configured to have a first height during the building stage and a second height during the gas washing stage, wherein the first height is greater than the second height.

[0013] According to a preferred embodiment of the first aspect, the device further comprises: a motion unit connected to the beam unit and configured to drive the beam unit to move so that it is docked with the notch through the hatch, and then to disengage from the notch and the hatch in sequence and expose at least part of the notch and the hatch.

[0014] According to a preferred embodiment of the first aspect, the device further comprises: a coating unit constructed in the forming chamber and configured to move in a coating direction to transport and uniformly coat powder above the building platform to form a powder layer for the beam unit to scan; wherein, at least during the gas washing stage, the coating unit is disposed outside the initial space.

[0015] According to a preferred embodiment of the first aspect, at least one end of the at least one layer of barrier is provided with a bent portion, and the bent portion forms a receiving space for receiving the coating unit.

[0016] According to a preferred embodiment of the first aspect, the apparatus further comprises: an air flow circulation system configured to collect the gas discharged from the forming chamber during the gas washing stage and guide the discharged gas above the scanning area of the beam for purging during the building stage.

[0017] According to a preferred embodiment of the first aspect, the apparatus further comprises: at least one filler having an expandable state and configured to expand and fill in the non-gas washing space of the forming chamber.

[0018] A second aspect of the present application provides an additive manufacturing apparatus, comprising: a forming chamber; a beam unit configured to control a beam to scan powder layer by layer in the forming chamber to build an object during a building stage; at least one barrier movably configured in the forming chamber and configured to divide at least a part of the forming chamber into an initial space to be gas washed during a gas washing stage; and a gas supply unit configured to charge a cleaning gas into the initial space and control the cleaning gas to gradually expand from the initial space to a target space as the at least one barrier moves, wherein the volume of the initial space is not less than the minimum volume that enables the cleaning gas to enter.

[0019] A third aspect of the present application provides an additive manufacturing apparatus, comprising: a forming chamber having a hatch at the top; a beam unit configured to control a beam to scan powder layer by layer in the forming chamber to build an object during a building stage; at least one barrier constructed horizontally in the forming chamber and having a notch corresponding to the hatch in the vertical direction, configured to divide at least a part of the forming chamber into a target space to be gas washed during a gas washing stage, wherein the beam unit can be docked through the hatch and the notch to construct the target space below the at least one barrier; and a gas supply unit configured to charge a cleaning gas into the target space.

[0020] A fourth aspect of the present application provides a gas washing method for an additive manufacturing apparatus, wherein the apparatus comprises: a forming chamber; a gas supply unit; a beam unit configured to control a beam to scan powder layer by layer in the forming chamber to build an object during a building stage; and at least one barrier movably configured in the forming chamber; wherein the method comprises: during the gas washing stage, controlling the at least one barrier to move in a predetermined direction in the forming chamber to a predetermined position to divide at least a part of the forming chamber into an initial space to be gas washed; controlling the gas supply unit to charge a cleaning gas into the initial space and controlling the cleaning gas to gradually expand from the initial space to a target space as the at least one barrier moves in a direction opposite to the predetermined direction, wherein the volume of the initial space is not less than the minimum volume that enables the cleaning gas to enter.

[0021] According to a preferred embodiment of the fourth aspect, during the purging stage, the movement of the barrier in the direction opposite to the predetermined direction satisfies the following relationship: V = K * (P i - P e - ΔP 0 ); where V is the movement speed of the barrier, K is a proportionality constant related to the barrier structure and friction characteristics, P i is the output pressure of the purging gas filled, P e is the ambient pressure, and ΔP 0 is the minimum pressure difference required to overcome the initial static friction of the barrier.

[0022] According to a preferred embodiment of the fourth aspect, the method further includes: adjusting the proportionality constant K and / or the minimum pressure difference ΔP 0 according to the material properties of the constructed object, and adjusting the output pressure P i of the purging gas filled accordingly.

[0023] It should be understood that the above general description and the following detailed description are only exemplary and do not limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings incorporated herein and forming a part of the specification illustrate one or more embodiments of the present application and, together with the description, are used to explain the principles of the present application and to enable those of ordinary skill in the relevant art to make and use the present application.

[0025] Figure 1A is a schematic diagram of an exemplary conventional additive manufacturing device during the building stage;

[0026] Figure 1B is a schematic diagram of an exemplary conventional additive manufacturing device during the purging stage;

[0027] Figure 2A and Figure 2B are respectively schematic diagrams of the structure of the forming chamber of an exemplary additive manufacturing device of the present application;

[0028] Figure 3 is a schematic diagram of the evolution of purging of an exemplary additive manufacturing device of the present application;

[0029] Figure 4 is a schematic diagram of a structure of an exemplary additive manufacturing device of the present application;

[0030] Figure 5 is a schematic diagram of another structure of an exemplary additive manufacturing device of the present application;

[0031] Figure 6 is a schematic diagram of the application of an exemplary additive manufacturing device of the present application during the object taking stage;

[0032] Figure 7 It is a schematic structural view of the forming chamber of the exemplary additive manufacturing equipment of the present application;

[0033] Figure 8A It is a schematic structural view of the forming chamber with fillers of the additive manufacturing equipment of the present application;

[0034] Figure 8B It is a schematic structural view of the additive manufacturing equipment with fillers of the present application;

[0035] Figure 9 It is a schematic flow chart of the gas scrubbing method for AM equipment of the present application. Detailed Embodiments

[0036] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are described so as to make the present application more thorough and complete, and to fully convey the concept of the example embodiments to those skilled in the art. The features, structures, or characteristics described may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to gain a deeper understanding of the embodiments of the present application.

[0037] The type of additive manufacturing (AM) involved herein is not specifically limited, and its scope of application covers various AM processes based on powder bed technology, including but not limited to laser powder bed fusion (LPBF), electron beam melting (EBM), selective laser melting (SLM), selective laser sintering (SLS), and other additive manufacturing processes that use powder as the building material.

[0038] The "powder" herein refers to the raw material used to build a three-dimensional object, whose physical structure is in the form of powder particles, and these particles can have different shapes, sizes, and particle diameters. Preferably, the powder is a metal powder, such as stainless steel, aluminum, aluminum alloy, titanium, and titanium alloy, etc.; in addition, in alternative embodiments, powders of ceramics, plastics, or composite materials can also be used to build three-dimensional objects.

[0039] Figure 1A Shows a conventional AM equipment in the building stage. The AM equipment 10 has a forming chamber 11, and the forming chamber 11 provides a closed working space for the building of the beam 152 on the powder bed PB.

[0040] The construction of the beam 152 in the powder bed PB is performed by the beam unit 15, which is used to control the beam 152 to scan the powder layer by layer in the forming chamber 11 during the construction stage to build an object. It mainly has a beam emitter 150 and a beam deflector 151. The beam deflector 151 is used to deflect the beam 152 along a predetermined trajectory to irradiate the powder, melt it and solidify it to form a solid structure (taking LPBF or SLM as an example). The beam 152 refers to various forms of energy focused into a beam shape. In addition to the laser beam, in some cases, it can also be an electron beam or other beam shapes. In one example, the beam unit 15 can be composed of optical elements such as a laser emitter, a collimating mirror, a galvanometer scanner, and a field lens in sequence along the propagation path of the light beam.

[0041] The AM device 10 also has a build cylinder 13 communicating with the forming chamber. The build cylinder 13 has a build platform 130 (substrate) and a lifter 131 arranged below the build platform 130. The build platform 130 can move up and down along the inner wall of the build cylinder 13 under the drive of the lifter 131 to promote the formation of the powder bed PB in the build cylinder 13 to build a three-dimensional object.

[0042] The AM device 10 also has a spreading unit 14 (such as a scraper or a roller). The spreading unit 14 is arranged in the forming chamber 11, specifically arranged on the processing plane at the bottom end of the forming chamber 11 and can move on the processing plane (i.e., move along the spreading direction) to layer by layer transport and evenly spread the powder P accumulated on one side of the processing plane onto the build platform 130 to form a flat powder layer PL.

[0043] The AM device 10 also has a powder cylinder 12. The powder cylinder 12 has a container 120 for storing the powder used for AM and a lifter 121 arranged below the container 120. The container 120 can overflow a part of the powder P to the processing plane under the drive of the lifter 121 for the spreading unit 14 located on the processing plane to transport and spread. In some examples, in addition to being arranged on the left side of the build cylinder 13 as shown Figure 1A in the figure, the powder cylinder 12 can also be arranged on the right side of the build cylinder 13, or can also be set to two and arranged on the left and right sides of the build cylinder 13 respectively (in this arrangement, the two powder cylinders 12 can be powder collectors for each other). As Figure 1A an addition or replacement of the example, the powder P can be processed by the spreading unit 14 without being in the form of being piled up on the processing plane. For example, the powder P can be released onto the build platform 130 by dropping powder from top to bottom (in this case, the setting of the powder cylinder 12 can be cancelled). It should be understood that the powder bed PB is an overall form stacked by multiple powder layers PL. After each layer is constructed, the build platform 130 will descend a distance to lay a new layer of powder on it. In this way, the powder layers PL stacked layer by layer finally form the entire powder bed 211.

[0044] Before AM, modeling software, such as computer-aided design (CAD) software, is required to create a three-dimensional model of the desired object. The three-dimensional model is then layered and divided into multiple planed sections, each of which represents a layer to be constructed, and corresponding layered data is generated. Through this layered processing, a series of layered data of the layers to be constructed are generated to describe the geometry and scanning path of each layer. The control device (such as a computer control system) can control the operation of the various components of the AM equipment based on these layered data, and realize layer-by-layer scanning to build a complete object.

[0045] In the AM device 10, the molding chamber 11 is usually filled with an inert gas (such as argon or nitrogen) to form a stable, low-oxygen environment, thereby effectively reducing oxidation and other adverse chemical reactions of metals or other printing materials during the construction process. To this end, the AM device 10 is usually also equipped with a gas supply unit 16, which is used to replace the original air in the molding chamber 11 by continuously injecting inert gas before building the object.

[0046] Figure 1B An example of AM equipment in the gas washing stage is shown, and its operation process generally includes: after starting the gas washing, the gas supply unit 16 continuously delivers inert gas to the entire molding chamber 11 until the indoor atmosphere reaches the predetermined requirements. However, due to the large volume of the molding chamber 11 (especially for AM equipment used to build large-sized objects), when the inert gas is injected into the entire space at one time, the gas flow distribution is often uneven, and it is easy to form local low flow rate or dead corner areas in certain areas. Insufficient gas replacement in these areas is likely to cause local residual air or impurity gas, thereby reducing the uniformity of the environment during the construction process. In addition, in order to achieve the expected atmosphere purity in the entire molding chamber 11, the gas washing process usually takes a long time, which prolongs the waiting period of the equipment and increases the energy consumption and operating cost of the overall process. In addition, since the entire large volume space needs to be replaced by gas, the required inert gas consumption is large, which further aggravates the waste of resources. Finally, during the gas washing process, due to the uneven gas flow, local pressure fluctuations are likely to occur, which sometimes have an adverse effect on the heat conduction and molten pool stability during the construction process, thereby affecting the construction quality of the object. Therefore, the existing gas washing technology still has room for improvement in ensuring the purity of the atmosphere in the molding chamber 11. How to achieve uniform and rapid gas washing, reduce gas consumption and shorten the gas washing time has become a technical problem that needs to be urgently solved in existing AM equipment.

[0047] To this end, the present application embodiment provides an improved AM device, which optionally adopts Figure 1A and Figure 1B The AM device 10 shown in the figure may be composed of any component, structure or function. For example, in some embodiments, the AM device of the present application may includeFigure 1A and Figure 1B the forming chamber 11, the beam unit 15, and the gas supply unit 16 disclosed in

[0048] Figure 2A and Figure 2B shows an example of the forming chamber structure provided by the embodiment of the present application. As Figure 2A and Figure 2B shown (also refer to Figure 1B ), the AM device 10 provided by the present application further has a barrier 110, which is arranged inside the forming chamber 11 and is arranged to be movable along the inner wall of the forming chamber 11. The movement of the barrier 110 can be carried out according to a predetermined time period and the scrubbing requirements. For example, in the scrubbing stage, by driving the barrier 110 to move in a predetermined direction (such as Figure 2A in the horizontal direction or Figure 2B in the vertical direction) to a preset position, the cavity of the forming chamber 11 is divided into several different regions. One of the divided regions is designated as the initial space 111 for scrubbing. The specific structure and arrangement manner of the barrier 110 are not limited to a single form: in some embodiments, the barrier 110 can be arranged in a single direction, or a combination of multiple barriers 110 can be adopted to achieve zoned scrubbing.

[0049] The specific form of the barrier 110 can be set. For example, it can adopt a plate-like structure as shown in Figure 2A and Figure 2B to form a planar shape to form a clear separation interface; it can also be set as a flexible curtain, and its material and structure allow the barrier to present a certain arc or curve shape. In addition, the barrier 110 can also be set as a structure with a wavy or other irregular contour to optimize the guiding and distribution of the airflow during scrubbing.

[0050] To achieve effective scrubbing of the initial space 111, one or more air inlets are provided on the side wall of the forming chamber 11. Figure 2A shows the symmetric air inlets 111A and 111B arranged on both sides of the forming chamber 11 in Figure 2B , and

[0051] Figure 2B shows the setting of the air inlet 111C. Through the connection with the gas supply unit 16, the cleaning gas 160 can be continuously transported into the initial space 111 during the scrubbing stage. At the same time, to achieve more efficient gas replacement and quickly expel the original air and impurities in the cavity, in some embodiments, an air outlet (not shown in the figure) is also provided on the side wall of the forming chamber 11 for discharging the gas displaced during scrubbing. In some embodiments, negative pressure suction can also be used for scrubbing, for example, using a vacuum pump to evacuate first and then inject an inert gas, without continuous exhaust.During the gas washing stage, the gas supply unit 16 continuously injects the cleaning gas 160 into the initially set volume of the initial space 111, so that this space can be quickly filled within a very short time. When the initial space 111 is filled with the cleaning gas 160, the target space is formed. At this time, the initial space 111 coincides with the target space, that is, the expansion rate of the initial space 111 to the target space is 0. This not only shortens the gas washing time, but also avoids the uneven air flow phenomenon common in the overall gas washing process. It should be understood that when the expansion rate of the initial space 111 to the target space is 0, that is, the volume of the initial space 111 remains unchanged during the gas washing process. In this embodiment, the original space required for constructing the object (whether it is the entire forming chamber 11 or a partial area thereof) is compressed into the initial space 111, so that the gas washing is only carried out within the initial space 111.

[0052] In some embodiments, the expansion rate of the initial space 111 to the target space can be greater than 0, that is, after the initial space 111 is filled with the cleaning gas 160, the initial space 111 is gradually expanded to the target space (the initial space 111 is part of the target space) by moving the barrier 110. This method can achieve step-by-step gas washing according to specific process requirements. Its advantage is that it further optimizes the gas distribution and pressure balance, providing a more stable environmental condition for the subsequent construction process. Specifically, during the gas washing stage, the gas supply unit 16 first fills the initial space 111 with the cleaning gas 160. After the initial space 111 is filled with the cleaning gas 160, that is, after the gas washing is completed, the gas supply unit 16 continues to fill the initial space 111 with the cleaning gas 160, and controls the cleaning gas 160 to gradually expand from the initial space 111 to the target space as the barrier 110 moves.

[0053] To enable the cleaning gas 160 to smoothly enter the initial space 111 during the gas washing stage, the volume of the initial space 111 is set to be not less than the minimum volume that allows the cleaning gas 160 to enter. Here, the "minimum volume" refers to the minimum volume requirement necessary to ensure that the cleaning gas 160 can fully flow in and completely fill this space under specific gas flow rate, output pressure, and flow velocity conditions. If the volume of the initial space 111 is less than this minimum value, the cleaning gas 160 may have poor flow due to excessive air flow resistance or insufficient inlet effect during the entry process, affecting the gas washing efficiency and atmosphere uniformity. On the contrary, by ensuring that the volume of the initial space 111 meets or exceeds this minimum requirement, the cleaning gas 160 can fill the initial space 111 within a very short time, quickly forming a stable and high-purity working environment. This can not only shorten the gas washing time, but also prevent local air flow disorder caused by insufficient space.

[0054] In some embodiments, the movement of the barrier 110 during the gas washing stage is driven by the pressure difference formed by the gas supply unit 16 continuously injecting the cleaning gas 160 into the initial space 111.Figure 3 The evolution process of the scrubbing of the additive manufacturing equipment of the present application is shown. Specifically, after the scrubbing is started, the gas supply unit 16 continuously injects the cleaning gas 160 into the initial space 111 at a predetermined flow rate and output pressure, resulting in a rapid increase in the air pressure in this space, while the air pressure outside the initial space is relatively low. This air pressure difference forms a net force on both sides of the barrier 110, causing it to receive a driving force in the direction of the target space 112. When this net force exceeds the static friction and other resistances of the barrier 110, the barrier 110 begins to automatically move along a predetermined trajectory, dividing the original larger space into the initial space 111 dedicated to scrubbing and the subsequently gradually expanding target space 112. As the barrier 110 moves, the cleaning gas 160 gradually diffuses from the initial space 111 to the target space 112 under the action of the pressure gradient, forming a continuous and stable scrubbing process. During the whole process, the moving speed and distance of the barrier 110 are determined by the air pressure difference formed by the continuously injected cleaning gas 160, without the need for an additional mechanical device for driving. In addition, adaptive control can also be realized: when the injection rate and pressure of the cleaning gas 160 meet the preset conditions, the barrier 110 moves smoothly, making the scrubbing process uniform and without obvious fluctuations; on the contrary, when the air pressure difference is not sufficient to drive the movement of the barrier 110, the control device connected to the gas supply unit 16 can compensate by adjusting the gas injection parameters to ensure that a high-purity atmosphere is always maintained. By using the method of driving the barrier 110 to move with the air pressure difference, the scrubbing speed can be accelerated, and the problems of uneven air flow and local dead corners commonly found in traditional overall scrubbing can be effectively avoided, providing a uniform gas environment for the subsequent construction stage.

[0055] The volume of the target space 112 can be defined. For example, in some examples, the volume of the target space 112 can be set to be equal to the overall volume of the forming chamber 11, that is, after the scrubbing stage is completed, the entire interior of the forming chamber 11 is filled with the cleaning gas 160, forming a uniform high-purity atmosphere. In other examples, the volume of the target space 112 can also be adjusted according to the forming requirements and scrubbing efficiency, and can be set to be smaller than the volume of the forming chamber 11, only covering a part of the construction area, so as to reduce the consumption of the cleaning gas 160 and improve the scrubbing efficiency.

[0056] As Figure 3As shown, in the specific structure, a guide rail 113 is further provided on the inner wall of the forming chamber 11 to provide movement guidance for the barrier 110. The guide rail 113 can be made into a groove, a protrusion or a channel structure, and its purpose is to enable the barrier 110 to slide smoothly along a predetermined direction when affected by a pressure difference or other driving forces, without lateral deviation or vibration. To achieve this purpose, a sliding member, a roller or a low-friction surface matching the guide rail 113 can be provided at the edge or bottom of the barrier 110, so that after the gas supply unit 16 continuously injects the cleaning gas 160, the pressure difference formed in the inner cavity drives the barrier 110 to move along the guide rail 113. In addition, the setting of the guide rail 113 can also play roles such as stabilizing the posture of the barrier 110, reducing the frictional resistance, and preventing the airtightness from decreasing due to uneven movement during the movement of the barrier 110. Combined with a position sensor or a feedback control system, the guide rail 113 can also monitor the real-time movement position of the barrier 110 to ensure that the barrier 110 always stays at a predetermined position during the gas washing process.

[0057] In some embodiments, the movement of the barrier 110 during the gas washing stage can be adjusted not only by the pressure difference but also by an electric drive control method. For this purpose, the AM device can further include a gas monitoring unit and a moving unit. The gas monitoring unit is used to monitor the gas filling amount in the initial space 111 in real time to judge whether the preset cleaning gas filling requirement is met. This monitoring can be carried out in various ways. For example, the gas pressure, flow rate or concentration in the initial space 111 can be directly measured to obtain the current gas filling amount; or it can be measured indirectly by calculating the current gas filling amount according to the known volume of the initial space 111, the gas delivery volume of the gas supply unit 16 and the time. The gas monitoring unit can transmit the detection data to the control device for subsequent movement control of the barrier 110. The moving unit is used to drive the barrier 110 to move when it is detected that the gas filling amount in the initial space 111 reaches the preset threshold, so that the initial space 111 expands towards the target space 112. The specific structure of the moving unit can be defined. For example, when the guide rail 113 is provided on the inner wall of the forming chamber 11, the moving unit can adopt a motor drive mechanism, such as a stepper motor or a servo motor, and the barrier 110 is moved along the guide rail 113 through a transmission structure (such as a rack and pinion, a ball screw or a linear drive device) connected to the barrier 110.

[0058] In some embodiments, the mobile unit may further include a deceleration device and a feedback control system. For example, by using a motor drive mechanism with a reduction gear set, the moving speed of the barrier 110 can be reduced, enabling it to gradually expand the target space 112 and avoiding turbulence and uneven atmosphere caused by too fast gas flow. The feedback control system can be combined with displacement sensors, pressure sensors, or ranging sensors, etc., to monitor the position and movement state of the barrier 110 in real time, and adjust the moving speed or stop moving according to the data of the gas monitoring unit to ensure the efficient and stable gas washing process.

[0059] Figure 4 shows the structure of the AM device of the present application. In Figure 4 In the shown AM device 10, a hatch 115 is provided at the top of the forming chamber 11. The barrier 110 is arranged horizontally in the forming chamber 11 and is provided with a notch 114. The hatch 115 and the notch 114 are (partially or completely) corresponding to each other in the vertical direction, and also (partially or completely) corresponding to the build platform 130 in the vertical direction. The beam unit 15 can be docked with the notch 114 through the hatch 115, so that its optical components can be effectively aligned and irradiated on the powder bed during the building process. More specifically, the beam unit 15 can achieve a sealed docking with the notch 114 through the hatch 115. For example, a seal can be provided at the docking position of the beam unit 15 and the notch 114 to form a seal when the beam unit 15 is docked with the notch 114. To achieve this docking, the beam unit 15 also has a housing 153 for accommodating optical elements such as a beam emitter 150 and a beam deflector 151. The housing 153 is composed of a main body portion 153A and an extension portion 153B. The main body portion 153A is arranged above the forming chamber 11, extends horizontally for a certain distance, and then extends downward to form the extension portion 153B. The extension portion 153B can be inserted from the hatch 115 and achieve precise docking with the notch 114, thereby positioning the working area of the beam unit 15 in the space below the barrier 110.

[0060] It should be understood that this arrangement actually reduces the building environment from the entire forming chamber 11 to the area below the barrier 110, that is, the target space 112 is constructed below the barrier 110. In this embodiment, the target space 112 is the same as the initial space 111 (i.e., the expansion rate of the initial space 111 to the target space 112 is 0). During the gas washing stage, the control device 17 controls the gas supply unit 16 to inject the cleaning gas 160 only into the space below the barrier 110 (which is both the initial space 111 and the target space 112) to achieve the gas washing process. Since only a smaller area below the barrier 110 is gas washed, the space required for gas washing is effectively reduced, the gas washing efficiency is improved, and the uniformity of the gas flow during the gas washing process can be ensured, without having an adverse impact on the object building process.

[0061] Continue to refer to Figure 4 In addition, the barrier 110 can also be configured to have different vertical heights during the building stage and the purging stage, namely a first height during the building stage and a second height during the purging stage, where the first height is greater than the second height. In this embodiment, the beam unit 15 is docked with the notch 114 through the hatch 115 to form an integral structure with the barrier 110, so that the barrier 110 and the beam unit 15 can move synchronously in the vertical direction. Specifically, during the building stage, in order to provide a larger height for the building environment to meet the requirement of scanning the powder bed within a larger angular range by the beam (for example, when building a large-format object), the control device 17 controls the motor drive mechanism to move the barrier 110 along the guide rail 113 on the inner wall of the forming chamber 11 and rise to a preset first height. At this time, the barrier 110 and the beam unit 15 move synchronously, so that the installation position of the beam unit 15 is consistent with the docking position of the barrier 110, thereby providing sufficient scanning height and field of view for large-format building. During the purging stage, in order to achieve a more efficient gas purging effect, the barrier 110 can be lowered from the first height to a preset second height. At this time, since the docking relationship between the barrier 110 and the beam unit 15 remains stable, the entire purging area is restricted to a lower height range, that is, the target space 112 (or the initial space 111) is the area below the barrier 110. By reducing the height of the purging area, the purging gas volume in the forming chamber 11 is significantly reduced, and the cleaning gas can quickly fill the purging area in a shorter time, thus realizing a fast and uniform purging process. In this way, through the height-adjustable setting scheme, the requirements of large-format scanning and complex component manufacturing can be met during the building stage, and at the same time, the purging efficiency can be improved by reducing the working area during the purging stage.

[0062] Figure 5 shows Figure 4 A variant embodiment is shown, in which the barrier 110 is divided into two independent parts, namely a first barrier 110A and a second barrier 110B. In this embodiment, the first barrier 110A is arranged in the upper part of the forming chamber 11, and the second barrier 110B is located below the first barrier 110A. A notch 114 is formed on the first barrier 110A. Through this notch 114, the beam unit 15 can be inserted from the hatch 115 at the top of the forming chamber 11 and docked with the first barrier 110A to realize the normal operation during the building stage. Since the beam unit 15 and the first barrier 110A are docked through the notch 114, the building environment is mainly located in the area below the first barrier 110A.

[0063] In the gas washing stage, the second barrier 110B is configured to divide at least a part of the space below the first barrier 110A into an initial space 111 for gas washing. For example, the space below the second barrier 110B can be both the initial space 111 and the target space 112. The build environment is further compressed within the space below the second barrier 110B. In the gas washing stage, the control device 17, by controlling the gas supply unit 16, only needs to inject the cleaning gas into the space below the second barrier 110B (which is both the initial space 111 and the target space 112) to achieve the gas washing process. Since the volume of the gas washing area is effectively compressed, the cleaning gas can fill this area in a very short time, improving the gas washing efficiency. And because the space size is small, it is also easier to achieve uniform distribution of the air flow, avoiding local dead corners or uneven air flow phenomena that occur in traditional overall gas washing. To ensure that the beam can still effectively irradiate the build platform 130 during the gas washing stage, the second barrier 110B is provided with a transparent area at least in the vertical direction corresponding to the build platform 130, so that the beam unit 15 can penetrate this area to irradiate the powder bed on the build platform 130, even when the build space is compressed during the gas washing process.

[0064] The volume of the space below the second barrier 110B can be set, that is, the volume of the build environment can be set. For example, in the gas washing stage, the second barrier 110B can move along the inner wall of the forming chamber 11 (such as driven by a pressure difference). The gas supply unit 16 is configured to control the cleaning gas to gradually expand from the initial space 111 to the target space 112 as the second barrier 110B moves. The movement of the second barrier 110B can adjust the volume of the gas washing area, and its movement parameters (such as speed, distance) can also be preset and controlled according to actual process requirements, so that the cleaning gas can gradually expand from the initial space 111 to the target space 112, realizing step-by-step and uniform gas washing. It can be seen that through the synergistic effect of the first barrier 110A and the second barrier 110B, it is possible to achieve the normal docking and efficient operation of the beam unit 15 during the build stage, while effectively compressing the build environment during the gas washing stage, improving the gas washing efficiency and improving the air flow uniformity.

[0065] In some embodiments, after the construction phase is completed and when it is necessary to take out the constructed object, the control device 17 can instruct the barrier 110 to move to drive the beam unit 15 to disengage from the notch 114 and the bin opening 115 in sequence. Specifically, the barrier 110 can gradually retreat (ascend) along the guide rail 113 on the inner wall of the forming chamber 11, so that the area originally blocked by the notch 114 is gradually exposed, and at the same time, the area of the bin opening 115 is also revealed. This process enables the overall linkage structure of the beam unit 15 and the barrier 110 to disengage from the original docking state during the object taking phase, providing the necessary space for the subsequent object taking. At the same time, the control device 17 also instructs the elevator 131 to drive the construction platform 130 to ascend along the inner wall of the construction cylinder 13 until it completely disengages from the bin opening 115. In this setting, the width of the construction cylinder 13 is the same as the width of the extension 153B of the housing 151 of the beam unit 15, so that after the beam unit 15 is separated from the barrier 110, the construction platform 130 can be smoothly exposed in the object taking area above the forming chamber 11. The advantage is that even when constructing objects with a relatively large size, it can avoid the difficulty of taking out objects due to the insufficient overall height of the forming chamber 11, enabling the staff to directly take out the constructed objects from above the forming chamber 11.

[0066] It should be understood that although the barrier 110 can move synchronously with the beam unit 15 through the guide rail 113, due to certain limitations on the height of the guide rail 113, the ascending height of the beam unit 15 is also limited. For this reason, the AM device of the present application is separately equipped with a motion unit. Figure 6 Shows the application of the AM device in the object taking phase. Refer to Figure 6 , the motion unit 18 is configured to be connected to the beam unit 15 and is configured to drive the beam unit 15 to move during the gas washing phase and the construction phase, so that it passes through the bin opening 115 and docks with the notch 114, and during the object taking phase, drive the beam unit 15 to disengage from the notch 114 and the bin opening 115 in sequence, and expose at least part of the notch 114 and the bin opening 115 for taking out the object. In terms of specific structure, the motion unit 18 can adopt a lifting device, a linear actuator or a multi-axis (X-axis, Y-axis and Z-axis) motion mechanism, such as a robotic arm, etc., to meet the requirements for taking out constructed objects of different sizes and complexities. Through the detachable combination of the top bin opening 114 of the forming chamber 11 and the beam unit 15, the constructed object can be directly taken out from the top bin opening 114 of the forming chamber 11, removing the restriction on the height of the constructed object by the side opening, and being applicable to taking parts of large-sized or high aspect ratio objects.

[0067] In some embodiments, the height of the forming chamber 11 is less than the length and / or width to construct a flattened indoor structure. The flattened structure of the forming chamber 11 can, on the one hand, reduce the air flow disturbance inside the chamber to optimize the wind field; on the other hand, it can reduce the height of the AM device, which is suitable for low equipment spaces.

[0068] In one example, the height of the forming chamber 11 is at least less than half of the length and / or width to optimize the aspect ratio of the forming chamber 11, making it longer in the length direction and significantly reduced in the height direction.

[0069] In one example, the length of the forming chamber 11 is twice the width and the height is half of the width to construct a flattened structure. The forming chamber 11 has a significant aspect ratio, that is, its length is much greater than the width, making the overall structure more flattened and suitable for constructing slender objects such as aerospace structural parts, guide rails, and tubular components.

[0070] In one example, the length of the forming chamber 11 is close to the width and the height is half of the length or width to construct a flattened structure. The forming chamber 11 is suitable for large flat objects.

[0071] It should be understood that the structure of the forming chamber 11 is not limited to the aspect ratio of length, width, and height provided in the above examples, and it can be any ratio to construct the flattened forming chamber 11.

[0072] In some embodiments, when the coating unit 14 disclosed above is provided in the forming chamber 11, since the coating unit 14 is configured on the processing plane, its structural height will affect the moving range of the barrier 110. Specifically, the barrier 110 will be restricted by the height of the coating unit 14 during the descending process, thereby affecting its ability to compress the space during the gas washing stage. Therefore, in order to optimize the space utilization rate during the gas washing stage, the present application proposes an improvement scheme, that is, during the gas washing stage, the coating unit 14 is located outside the initial space 111, so that the barrier 110 can descend more significantly, realizing further compression of the construction space.

[0073] Figure 7 An example of the forming chamber structure provided by the embodiment of the present application is shown. In this example, a bending portion 116 is provided at one end of the barrier 110, and the bending portion 116 forms a space for accommodating the coating unit 14. During the gas washing stage, the control device 17 can instruct the coating unit 14 to move into the accommodating space formed by the bending portion 116, so that the coating unit 14 does not affect the descending range of the barrier 110. In this state, the volume of the initial space 111 is further compressed, enabling the cleaning gas to flow efficiently in a smaller space and enhancing the effect of the gas washing process. In addition, the setting position of the bending portion 116 is not limited to one side of the barrier 110. In some variant embodiments, the bending portion 116 can be provided at the other end of the barrier 110, or provided at both ends of the barrier 110 to meet the requirements of different equipment layouts.

[0074] In addition to optimizing the space utilization rate in the gas washing stage, the bending part 116 can also be used in the building stage to further compress the volume of the building space and improve the building efficiency. For example, in the building stage, after the coating unit 14 completes one powder delivery and coating, the control device 17 can drive it to move into the accommodation space formed by the bending part 116, so as to temporarily avoid the processing area. In this state, the control device 17 can further drive the barrier 110 (especially the second barrier 110B in the Figure 5 example) to move downward, so that the building space is maintained within the smallest possible volume range, in order to improve the energy utilization rate and reduce external environmental interference. After the current layer is built, the control device 17 drives the barrier 110 to rise again, so that the coating unit 14 returns to the processing plane and continues to perform subsequent powder coating operations.

[0075] It should be understood that the advantage of the above solution is that the bending part 116 of the barrier 110 cleverly provides a storage space for the coating unit 14, and maximally optimizes the space utilization rate in the gas washing and building stages without affecting the normal processing flow.

[0076] In some embodiments, the gas supply unit 16 can also be configured to blow air above the scanning area (i.e., the powder bed) of the beam during the building stage. Specifically, this configuration includes setting a wind guiding system or nozzle on the side of the forming chamber 11 to blow air flow directly above the powder bed. This air flow forms a protective air hood to reduce air flow disorder. By controlling the wind speed, wind direction and temperature of the blowing, the gas supply unit 16 can inhibit the scattering of processing debris caused by local air flow fluctuations, and can slow down the influence of external environmental temperature changes on the molten pool and solidification process, thereby improving the uniformity of heat transfer during the building process.

[0077] In some embodiments, the AM device 10 further includes an air flow circulation system, which is configured to collect the gas discharged from the forming chamber 11 in the gas washing stage and guide the discharged gas above the scanning area of the beam 152 for purging during the building stage. The air flow circulation system can include, for example, a gas collection device, a processing module and a wind guiding pipeline. In the gas washing stage, the gas discharged from the forming chamber 11 is captured by the gas collection device through a preset exhaust port and transported to the processing module for purification and pressurization treatment to meet the requirements of subsequent purging. The processed gas is then redirected above the scanning area of the beam 152 through the wind guiding pipeline to form a uniform and stable purging air flow, so as to remove the dust and particles suspended in the scanning area and maintain the stability of the environmental atmosphere above the scanning area, ensuring ideal optical transmission and heat transfer effects when the beam 152 scans the powder bed.

[0078] It should be understood that in some of the examples described above, by compressing the scrubbing space of the forming chamber 11, the scrubbing space that originally needed to be compressed for the entire forming chamber 11 is compressed into the target space. However, during actual scrubbing operations, due to mechanical structure limitations, it is difficult to achieve complete sealing of the scrubbing space. Therefore, when scrubbing the scrubbing space (initial space / target space), the cleaning gas filled is likely to leak into the non-scrubbing space of the forming chamber 11. For this reason, the AM device 10 of the present application further includes at least one filler, and the at least one filler has an expandable state and is configured to expand and fill in the non-scrubbing space of the forming chamber 11.

[0079] Figure 8A The schematic structural diagram of the forming chamber with fillers is shown. Figure 8B The schematic structural diagram of the AM device with fillers is shown. Figure 8A Based on Figure 2A the example is deformed, that is, fillers 19A and 19B are added on the basis of the original structure; Figure 8B Then based on Figure 4 the example is similarly deformed, that is, fillers 19A and 19B are added to the structure where the beam unit 15 is docked with the barrier 110. Referring to Figure 8A , assuming that the target moving position of the barrier 110 in the forming chamber 11 is represented by a dotted line, the area formed below the dotted line is the target space required during scrubbing, and the area above the dotted line constitutes the non-scrubbing space 117. In this arrangement, the scrubbing area and the non-scrubbing area are physically separated. Referring to Figure 8B , the beam unit 15 can be docked with the notch 114 on the first barrier 110A through the hatch 115 to compress the object building area (i.e., the scrubbing space) below the barrier 110; a non-scrubbing space 117 is formed above the barrier 110. During the scrubbing stage, gas is filled into the fillers (such as fillers 19A and 19B) in the non-scrubbing space 117 through the gas filling device 190, causing them to expand rapidly. The expanded fillers can occupy most of the volume of the non-scrubbing space 117, ensuring that even if there is a certain degree of gas leakage during the scrubbing stage, since the non-scrubbing space 117 is mainly filled with fillers, its impact on the atmosphere in the scrubbing area can be ignored.

[0080] It should be understood that the present application does not limit the number of fillers, and one or more fillers can be set according to the specific device structure and scrubbing requirements; at the same time, the present application does not limit the specific form of the fillers, as long as the fillers can expand after being filled with gas and occupy the volume of the non-scrubbing space. For example, the fillers can be in the form of airbags, expandable foams or other structures with similar expansion properties to achieve the expected space occupation effect.

[0081] Referring to FIGS. 1 to Figure 3, the barrier 110 undergoes at least two movement processes within the forming chamber 11 to achieve an efficient and uniform gas scrubbing effect. First, at the initial stage of gas scrubbing, the control device 17 sends an instruction to the barrier 110 to move it to a preset position along a predetermined direction (e.g., from top to bottom), thereby dividing a part of the area of the forming chamber 11 into an initial space 111 to be gas-scrubbed. Subsequently, during the gas scrubbing process, the gas supply unit 16 continuously injects the cleaning gas 160 into the initial space 111, resulting in a continuous increase in the air pressure within the initial space. The control device 17 monitors the charging amount of the cleaning gas 160 in real time during this process and, by adjusting the gas transmission parameters, enables the cleaning gas 160 to gradually expand from the initial space 111 to the target space 112 under the action of the pressure gradient. Specifically, when the pressure within the initial space 111 reaches the preset threshold, the barrier 110 starts to slowly retreat in the direction opposite to the initial movement direction under the drive of the pressure difference, further expanding the gas scrubbing area to the target space 112.

[0082] In some embodiments, for example, during the gas scrubbing stage, the gas supply unit 16 continuously injects the cleaning gas 160 into the initial space 111, causing the pressure in this space to rise rapidly, thereby forming a net pressure difference between the initial space 111 and the surrounding area. This pressure difference is determined by the output pressure P i of the cleaning gas 160 charged by the gas supply unit 16 e and the ambient pressure P 0 , but must overcome the minimum pressure difference ΔP required to overcome the initial static friction of the barrier 110 0 . For example, it exceeds the minimum pressure ΔP required to overcome the static friction between the barrier 110 and its guide rail or the inner wall of the forming chamber i . When (P e - P 0 ) > ΔP i , the net driving force is (P e - P 0 - ΔP i ). This driving force prompts the barrier 110 to move smoothly in the direction opposite to the predetermined direction, and its moving speed V is proportional to the net driving force. The relationship is: V = K * (P e - P 0 - ΔP

[0083] . Among them, the proportionality constant K represents factors such as the structural characteristics and friction coefficient of the barrier 110. During this process, as the cleaning gas 160 continues to be injected, the net pressure difference gradually increases, enabling the barrier 110 to move at a stable and controllable speed, gradually expanding the initial space 111 into the target space 112, and achieving continuous expansion of the gas scrubbing area. 0, and accordingly adjust the output pressure P of the purging gas filled therein i Specifically, different materials (such as metal powders like stainless steel, titanium, aluminum alloy, or ceramic and plastic powders) have different requirements for the environmental atmosphere, temperature distribution, and oxygen content during the forming process. This requires the airflow and pressure control during the gas washing process to achieve the best match. To this end, the control device can adjust the proportional constant K related to the movement of the barrier 110 and the minimum pressure difference ΔP required to overcome the static friction of the barrier 0 For example, when constructing materials with high melting points and strict requirements for the atmosphere, it is necessary to reduce the value of K and / or increase ΔP 0 to make the acceleration and displacement of the barrier 110 more stable when moving, and prevent airflow disturbance from affecting the forming quality; conversely, for materials with more lenient requirements for the atmosphere, the value of K can be appropriately increased or ΔP can be reduced 0 to achieve faster barrier movement and a more rapid gas washing process. At the same time, the control device can, according to the adjusted parameters, adjust the output pressure P of the gas supply unit i so that the injected purging gas 160 can meet the net pressure difference requirement during the gas washing process (i.e., P i -P e -ΔP 0 ), and at the same time, be able to control the moving speed of the barrier 110 (satisfying V = K*(P i -P e -ΔP 0 )) to enable the gas washing process to meet the requirements of different materials in terms of atmosphere, temperature, and pressure, and at the same time optimize the gas washing efficiency.

[0084] It should be understood that the above control process of the control device can also constitute a gas washing method for the AM device, and this gas washing method can be implemented in whole or in part through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions according to the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium.

[0085] Further examples are described below to facilitate the understanding of the AM device of the present application.

[0086] Aspect 1: Provide an AM device, comprising: a forming chamber; a beam unit configured to control a beam to scan powder layer by layer in the forming chamber to build an object during a building phase; at least one layer of barrier movably constructed in the forming chamber and configured to divide at least a part of the forming chamber into an initial space to be purged during a purging phase; and a gas supply unit configured to fill the initial space with a cleaning gas and control the cleaning gas to gradually expand from the initial space to a target space.

[0087] Aspect 2: Provide an AM device, comprising: a forming chamber; a beam unit configured to control a beam to scan powder layer by layer in the forming chamber to build an object during a building phase; at least one layer of barrier movably constructed in the forming chamber and configured to divide at least a part of the forming chamber into an initial space to be purged during a purging phase; and a gas supply unit configured to fill the initial space with a cleaning gas and control the cleaning gas to gradually expand from the initial space to a target space as the at least one layer of barrier moves, wherein the volume of the initial space is not less than the minimum volume that enables the cleaning gas to enter.

[0088] Aspect 3: Provide an AM device, comprising: a forming chamber with a hatch opening at its top; a beam unit configured to control a beam to scan powder layer by layer in the forming chamber to build an object during a building phase; at least one layer of barrier constructed horizontally in the forming chamber and having a notch corresponding to the hatch opening in the vertical direction, configured to divide at least a part of the forming chamber into a target space to be purged during a purging phase, wherein the beam unit can be docked with the hatch opening and the notch to construct the target space below the at least one layer of barrier; and a gas supply unit configured to fill the target space with a cleaning gas.

[0089] Figure 9 Shows the purging method flow for the AM device of the present application. Refer to Figure 9 , in a basic method flow example, specifically during the purging phase, the method 20 has the following steps 201 and 202.

[0090] 201. Control at least one layer of barrier to move in a predetermined direction in the forming chamber to a predetermined position to divide at least a part of the forming chamber into an initial space to be purged.

[0091] 202. Control the gas supply unit to fill the initial space with a cleaning gas and control the cleaning gas to gradually expand from the initial space to a target space as the at least one layer of barrier moves in a direction opposite to the predetermined direction, wherein the volume of the initial space is not less than the minimum volume that enables the cleaning gas to enter.

[0092] Other embodiments of the present application will be readily contemplated by those skilled in the art upon consideration of the specification and practice of the disclosure herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include known common knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and examples are only regarded as exemplary, and the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. An additive manufacturing device, comprising: Molding room; A beam unit configured to control the beam to scan the powder layer by layer in the molding chamber to build the object during the building phase; at least one barrier movably constructed in the molding chamber and configured to divide at least a portion of the molding chamber into an initial space to be scrubbed during the scrubbing stage; as well as The gas supply unit is configured to fill the initial space with cleaning gas and control the cleaning gas to gradually expand from the initial space to the target space.

2. The device according to claim 1, wherein: The gas supply unit is further configured to control the cleaning gas to gradually expand from the initial space to the target space as the at least one barrier moves, wherein the volume of the initial space is not less than a minimum volume that allows the cleaning gas to enter.

3. The device according to claim 2, wherein: The movement of the at least one barrier during the scrubbing phase is driven by the pressure difference formed by continuously filling the initial space with the scrubbing gas.

4. The device according to claim 2, further comprising: A gas monitoring unit configured to monitor the gas volume in the initial space in real time; as well as The moving unit is configured to drive the at least one layer of barrier to move when it is detected that the air volume in the initial space reaches a preset threshold, so as to transform the initial space into a target space.

5. The device according to claim 1, wherein: The at least one barrier is horizontally constructed in the molding chamber and is provided with slots; A hatch is provided on the top of the molding chamber, and the hatch and the notch correspond to each other in the vertical direction; The beam unit can be docked with the slot through the bay opening to construct the target space below the at least one barrier layer.

6. The device according to claim 5, wherein: The expansion rate of the initial space to the target space is 0.

7. The device according to claim 5, wherein: The at least one barrier layer comprises a first barrier and a second barrier located below the first barrier, The notch is opened on the first barrier, The second barrier is configured to divide at least a portion of the space below the first barrier into an initial space during the scrubbing phase, The gas supply unit is further configured to control the cleaning gas to gradually expand from the initial space to the target space as the second barrier moves.

8. The device according to claim 5, wherein: The at least one barrier is configured to have a first height in the building phase and a second height in the scrubbing phase, wherein the first height is greater than the second height.

9. The device according to claim 5, further comprising: The motion unit is connected to the beam unit and is configured to drive the beam unit to move so that it can dock with the slot through the bay opening, and to detach from the slot and bay opening in turn and make the slot and bay opening at least partially exposed.

10. The device according to any one of claims 1 to 9, further comprising: A coating unit is constructed in the molding chamber and is configured to move along a coating direction to transport and evenly coat the powder onto the building platform to form a powder layer for scanning by the beam unit; Wherein, at least in the washing stage, the smearing unit is arranged outside the initial space.

11. The device according to claim 10, wherein: At least one end of the at least one layer of barrier is provided with a bending portion, and the bending portion forms an accommodating space for accommodating the smearing unit.

12. The device according to any one of claims 1 to 9 and 11, further comprising: The gas circulation system is configured to collect the gas exhausted from the molding chamber in the purge phase and guide the exhausted gas to the scanning area of ​​the beam for purging in the build phase.

13. The device according to any one of claims 1 to 9 and 11, further comprising: At least one filler is in an expandable state and is configured to be expanded and filled in the non-washing space of the molding chamber.

14. An additive manufacturing device comprising: Molding room; A beam unit configured to control the beam to scan the powder layer by layer in the molding chamber to build the object during the building phase; at least one barrier movably constructed in the molding chamber and configured to divide at least a portion of the molding chamber into an initial space to be scrubbed during the scrubbing stage; as well as The gas supply unit is configured to fill the initial space with cleaning gas and control the cleaning gas to gradually expand from the initial space to the target space as the at least one barrier moves, wherein the volume of the initial space is not less than the minimum volume that allows the cleaning gas to enter.

15. An additive manufacturing device comprising: A molding chamber, with a hatch opening on the top; A beam unit configured to control the beam to scan the powder layer by layer in the molding chamber to build the object during the building phase; At least one barrier is constructed in the molding chamber in a horizontal direction and is provided with a slot corresponding to the porthole in a vertical direction, and is configured to divide at least a portion of the molding chamber into a target space to be scrubbed during the scrubbing stage, wherein the beam unit can be connected to the slot through the porthole to construct the target space below the at least one barrier; as well as The gas supply unit is configured to fill the target space with a cleaning gas.

16. A gas scrubbing method for an additive manufacturing device, wherein the device comprises: Molding room; Gas supply unit; A beam unit configured to control the beam to scan the powder layer by layer in the molding chamber to build the object during the building phase; as well as at least one barrier movably configured within the molding chamber; The method comprises: During the scrubbing phase, Controlling the at least one barrier to move to a predetermined position in a predetermined direction within the molding chamber to divide at least a portion of the molding chamber into an initial space to be scrubbed; The gas supply unit is controlled to fill the initial space with cleaning gas, and the cleaning gas is controlled to gradually expand from the initial space to the target space as the at least one layer of barrier moves in a direction opposite to the predetermined direction, wherein the volume of the initial space is not less than the minimum volume that allows the cleaning gas to enter.

17. The method according to claim 16, wherein: During the scrubbing phase, The movement of the barrier in the opposite direction to the predetermined direction satisfies the following relationship: V=K*(P i -P e -ΔP0); Where V is the moving speed of the barrier, K is the proportional constant related to the barrier structure and friction characteristics, and P i is the output pressure of the cleaning gas filled, P e is the ambient pressure, and ΔP0 is the minimum pressure difference required to overcome the initial static friction of the barrier.

18. The method according to claim 17, further comprising: The proportional constant K and / or the minimum pressure difference ΔP0 are adjusted according to the material properties of the object being constructed, and the output pressure P of the cleaning gas filled in is adjusted accordingly. i Make adjustments.

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