A wind field system for airflow uniform distribution for large-format forming platforms in additive manufacturing

Abstract

This application relates to the field of additive manufacturing technology, and in particular to an airflow distribution system for a large-format additive manufacturing platform. The system includes an inlet tee unit and a negative pressure exhaust unit. The inlet tee unit comprises a main air supply duct, an upper air outlet duct, and a lower air outlet duct. Both the upper and lower air outlet ducts are equipped with a flow-dividing grid assembly, which divides the outlets of the upper and lower air outlets into several sub-outlets of the same opening size. Each outlet of the upper and lower air outlets is equipped with a guide pipe. An airflow dispersion unit is located on one side of the guide pipe near the sub-outlet, and a straight air outlet is formed on the other side of the guide pipe. A conical flow channel with a conical cross-section is formed between the airflow dispersion unit and the straight air outlet. This application achieves uniform airflow distribution across all areas of the large-format additive manufacturing platform under low airflow conditions through multi-stage flow diversion and guidance design.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing technology, and in particular to a wind field system for uniformly distributing airflow for a large-format additive manufacturing platform. Background Technology

[0002] In the field of additive manufacturing, selective laser melting (SLM) technology is increasingly widely used in industrial production. With the expansion of printing areas and the increase in layer thickness, airflow control within the forming chamber has become a core bottleneck restricting the development of SLM technology. For this technology, an ideal airflow within the forming chamber needs to achieve uniform coverage of the entire forming platform. This means ensuring that the airflow can promptly remove smoke and splatter generated during the printing process, while also maintaining a stable thermal field to prevent thermal stress deformation of the printed parts due to uneven heat dissipation.

[0003] To achieve the ideal airflow field, existing technologies typically employ a single high-speed airflow circulation mode. This involves increasing the airflow coverage by introducing high-speed airflow and increasing the air volume, while adding a heat exchanger in the middle of the airflow duct to cool the duct and prevent the laser and galvanometer from overheating. However, in practical use, it has been found that a single high-speed airflow circulation mode cannot guarantee the uniformity of airflow on the large-format forming platform, making it difficult to cover the large-format printing platform. This can easily lead to the residue of smoke and splashed debris, affecting print quality. At the same time, high-speed airflow can easily cause filter clogging, increasing the frequency of backflushing and cleaning the filter, thus reducing its lifespan. Furthermore, high-volume airflow can cause vibration and temperature rise in the airflow bends, leading to an overall temperature rise in the forming chamber and affecting the cooling control of the laser and galvanometer. Even with the addition of a heat exchanger to cool the duct, these problems cannot be fundamentally solved. In addition, the addition of a heat exchanger also increases the complexity of the system and production costs.

[0004] Therefore, there is an urgent need for an airflow structure that can improve filter life and reduce the rate of temperature rise in the molding chamber by reducing airflow rate, while ensuring the uniformity and stability of airflow in large-format printing platforms and thick-layer sintering scanning, under the premise of ensuring airflow uniformity and stability. Summary of the Invention

[0005] In order to reduce airflow while ensuring the uniformity and stability of airflow in the large-format printing platform, this application provides an airflow uniform distribution airflow system for large-format additive manufacturing platforms.

[0006] This application provides a wind field system for uniform airflow distribution in a large-format additive manufacturing platform, which adopts the following technical solution:

[0007] A wind field system for uniform airflow distribution in a large-format additive manufacturing platform includes an inlet tee unit and a negative pressure exhaust unit. The inlet tee unit comprises a main air supply duct, an upper air outlet duct, and a lower air outlet duct. The connection between the main air supply duct and the upper and lower air outlet ducts is an arc transition, and the opening size of the connection between the upper air outlet duct and the main air supply duct is smaller than the opening size of the connection between the lower air outlet duct and the main air supply duct. A flow-diverting grid assembly is installed inside both the upper and lower air outlet ducts. The air outlets of the upper and lower air outlets are divided into several sub-air outlets with the same opening size. A guide pipe is provided at the air outlet of both the upper and lower air outlets. An airflow dispersion unit is provided on one side of the guide pipe near the sub-air outlet. Multiple straight air outlets are formed on the other side of the guide pipe. The airflow channel between the airflow dispersion unit and the straight air outlets is set as a conical flow channel with a conical cross-section, and the smaller opening end of the conical flow channel faces the straight air outlet.

[0008] The airflow dispersion unit is used to disperse the inertial airflow flowing out of the sub-outlet and redistribute it so that it is evenly distributed in the conical flow channel. The conical flow channel is used to compress and accelerate the dispersed airflow and guide it into the straight air outlet. The airflow is then delivered to the laser lens protection area and the forming platform protection area through the straight air outlet to form lens protection airflow and printing area protection airflow respectively. The negative pressure exhaust unit is used to extract the lens protection airflow and printing area protection airflow under negative pressure and re-converge them to guide the cyclone separator for filtration and recycling.

[0009] By adopting the above technical solution, with the cooperation of the air inlet tee unit, the diversion grille assembly, the airflow dispersion unit, the conical flow channel and the straight air outlet, the total airflow generated by the fan is diverted, dispersed, redistributed and guided in multiple stages. This achieves uniform distribution of airflow in all areas of the large-format forming platform, effectively preventing the accumulation of smoke and dust and splashes, improving printing quality. At the same time, it also achieves the effect of high-speed flow in the printing platform area with a small air volume, reducing the fan speed requirement, thereby effectively reducing fan energy consumption and filter load. It also avoids fan bend vibration and overheating problems caused by large air volume, and improves the stability of equipment operation.

[0010] Preferably, the diversion grid assembly includes a horizontal grid plate, a vertical grid plate, and a first arc-shaped guide plate. A plurality of first arc-shaped guide plates are provided, and the plurality of first arc-shaped guide plates are distributed at intervals on both sides of the vertical grid plate. A second arc-shaped guide plate is provided between two adjacent first arc-shaped guide plates. The length and curvature of the plurality of second arc-shaped guide plates are different.

[0011] By adopting the above technical solution, during use, the airflow delivered by the circular air inlet of the main air supply duct needs to be redistributed to cover the entire rectangular platform area. Under the guidance of the arc-shaped structure of the upper and lower air outlet ducts, the airflow must turn during the flow process. Due to the influence of the airflow inertia, the airflow that turns directly tends to converge into a bundle and flow in a certain area, making it difficult to achieve uniform airflow distribution. With the cooperation of the horizontal grid plate, the vertical grid plate, the first arc-shaped guide plate and the second arc-shaped guide plate, the airflow delivered by the main air supply duct is initially distributed and its flow direction is guided, so that it is divided into multiple airflows more evenly and flows out from multiple sub-air outlets with the same opening size, thereby improving the uniformity of airflow distribution at the air outlets of the upper and lower air outlet ducts.

[0012] Preferably, the airflow dispersion unit includes several sets of triangular perforated plates arranged in a linear array. Adjacent sets of triangular perforated plates are fixedly connected. Each triangular perforated plate includes a first vertical inclined plate and a second vertical inclined plate. The end of the first vertical inclined plate away from the sub-air outlet and the end of the second vertical inclined plate away from the sub-air outlet are fixedly connected. There is an included angle between the first vertical inclined plate and the second vertical inclined plate. Both the first vertical inclined plate and the second vertical inclined plate are provided with perforated holes. In the straight inertial airflow flowing out of the sub-air outlet, part of the airflow is deflected under the action of the inclined surfaces of the first vertical inclined plate and the second vertical inclined plate, while the other part of the airflow passes directly through the perforated holes.

[0013] By adopting the above technical solution, during use, under the guidance of the arc-shaped structure of the upper air outlet duct, lower air outlet duct, first arc-shaped guide plate, and second arc-shaped guide plate, the airflow flows in an arc shape. Due to the influence of flow inertia, the airflow in a single channel tends to converge to one side to form a straight inertial airflow, which then flows out from the sub-air outlet. In areas with less airflow distribution in the channel, vortex phenomena are easily formed. Therefore, the inclined surfaces of the first and second vertical inclined plates are used to deflect part of the straight inertial airflow flowing out of the air outlet. At the same time, the setting of the perforated holes allows some airflow to pass directly, thereby redistributing the straight inertial airflow in the corresponding area of ​​the airflow dispersion unit, so that the airflow in this area is evenly dispersed in the channel, while also suppressing the generation of vortex phenomena and ensuring the uniform flow of airflow afterwards.

[0014] Preferably, a reinforcing rib connects the first vertical inclined plate and the adjacent second vertical inclined plate.

[0015] By adopting the above technical solution, when in use, the connection strength of the first vertical inclined plate and the second vertical inclined plate is increased by reinforcing ribs, and several groups of airflow dispersion units are connected into a whole, reducing the probability of overall deformation of the airflow dispersion unit after airflow is introduced.

[0016] Preferably, the size of the perforations at both ends of the airflow dispersion unit is larger than the size of the perforation in the middle of the airflow dispersion unit.

[0017] By adopting the above technical solution, when in use, since the airflow in the middle of the sub-outlet is greater than the airflow on both sides, the airflow that passes directly through the larger perforated holes on both sides is increased, while the airflow reflected by the inclined surfaces of the first and second vertical inclined plates is reduced, thereby ensuring that the airflow dispersion unit disperses and redistributes the airflow from the sub-outlet.

[0018] Preferably, the negative pressure exhaust unit includes an upper exhaust pipe, a lower exhaust pipe, and a negative pressure tee pipe. The air inlet of the upper exhaust pipe is correspondingly arranged with the air outlet of the upper exhaust pipe, and the air inlet of the lower exhaust pipe is correspondingly arranged with the air outlet of the lower exhaust pipe. The air outlets of the upper and lower exhaust pipes are respectively connected to the two air inlets of the negative pressure tee pipe, and the air outlet of the negative pressure tee pipe is used to connect to a cyclone separator.

[0019] By adopting the above technical solution, during use, the lens protection airflow is drawn and recovered through the upper exhaust pipe, and the printing area protection airflow is drawn and recovered through the lower exhaust pipe. Then, the recovered lens protection airflow and printing area protection airflow are re-converged into one stream through the negative pressure three-way pipe and introduced into the cyclone separator for filtration. The filtered airflow is then recycled for subsequent reuse.

[0020] Preferably, both the upper and lower exhaust pipes are arrayed with a number of diversion grid plates. These diversion grid plates are used to ensure that the negative pressure distribution in each area of ​​the upper and lower exhaust pipes is uniform, and at the same time guide the airflow to enter the negative pressure tee pipe stably.

[0021] By adopting the above technical solution, during use, the flow channels inside the upper and lower exhaust pipes are divided into several flow channels by several diversion grid plates, thereby ensuring that the negative pressure distribution in each area of ​​the flow channel is uniform, thus ensuring the stability of the airflow in the subsequent suction forming cavity.

[0022] Preferably, a decorative grille is provided at the air inlet of the upper exhaust pipe.

[0023] By adopting the above technical solution, when in use, the decorative grille plate, on the one hand, corresponds to the structural shape formed by the straight air outlet, increasing the aesthetics of the overall structure, and on the other hand, forms an initial interception and filtration of the intake airflow.

[0024] Preferably, the air inlet of the lower exhaust pipe is provided with a guide plate, and the lowest end of the guide plate is flush with the top surface of the forming platform.

[0025] By adopting the above technical solution, the height of the flow channel inside the lower exhaust duct is raised by the guide ramp during use. This helps to guide the airflow in and also initially intercepts the heavier powder material, reducing the chance of the powder material being carried into the lower exhaust duct by the airflow. This reduces material consumption and saves printing material costs.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] 1. With the cooperation of the air inlet tee unit, the flow divider grid assembly, the airflow dispersion unit, the conical flow channel and the straight air outlet, the total airflow generated by the fan is multi-stage diverted, dispersed, redistributed and guided, realizing the uniform distribution of airflow in various areas of the large-format forming platform, effectively preventing the accumulation of smoke and dust and splashes, improving printing quality, and also achieving the effect of high-speed flow in the printing platform area with a small air volume, reducing the fan speed requirement, thereby effectively reducing fan energy consumption and filter load, and avoiding fan bend vibration and overheating problems caused by large air volume, thus improving the stability of equipment operation;

[0028] 2. Through the cooperation of several sets of first and second vertical inclined plates and hollow holes, the straight inertial airflow formed by the upper and lower air outlet pipes, the first arc-shaped guide plate and the second arc-shaped guide plate of the arc structure are effectively dispersed, while suppressing the formation of vortex phenomenon in the flow channel, and ensuring that the airflow distribution in the corresponding area of ​​the airflow dispersion unit is more uniform.

[0029] 3. By improving the uniform distribution of airflow on the large-format forming platform, the thermal field distribution inside the forming chamber is optimized, ensuring uniform heat dissipation of printed parts and reducing thermal stress deformation and cracking.

[0030] 4. By raising the height of the flow channel inside the lower exhaust duct through the guide ramp, the waste of powder caused by excessive regional airflow is reduced while realizing the recovery of airflow, thus improving the material utilization rate. Attached Figure Description

[0031] Figure 1 This is an isometric schematic diagram of the overall structure installation state, which is the main embodiment of this application.

[0032] Figure 2 This is an isometric schematic diagram of the main overall structure in the embodiments of this application;

[0033] Figure 3 This is a structural analysis diagram illustrating the external design of the air inlet tee unit in the embodiments of this application;

[0034] Figure 4 This is a cross-sectional view of the internal structure of the air inlet tee unit, which is the main feature of this application embodiment;

[0035] Figure 5 This is a schematic diagram illustrating the main distribution structure of the sub-air outlets in the embodiments of this application;

[0036] Figure 6 This is an isometric schematic diagram showing the main distribution positions of the diversion grid assembly in the embodiments of this application;

[0037] Figure 7 This is an isometric schematic diagram of the main airflow dispersion unit structure in the embodiments of this application;

[0038] Figure 8 yes Figure 6 The image mainly shows an enlarged view of the structure of section A;

[0039] Figure 9 This is a cross-sectional view of the main structure of the negative pressure exhaust unit in the embodiments of this application;

[0040] Figure 10 This is a schematic diagram illustrating the main distribution structure of the diversion grid plate in the embodiments of this application;

[0041] Figure 11 This is a schematic diagram of the airflow distribution simulation results corresponding to different distribution states of the diversion grid assembly in the embodiments of this application;

[0042] Figure 12 This is a schematic diagram of the simulation results of the sub-outlet flow velocity corresponding to different distribution states of the diversion grille assembly in the embodiments of this application;

[0043] Figure 13 This is a schematic diagram of the flow velocity simulation results of the corresponding region of the airflow dispersion unit in the embodiments of this application;

[0044] Figure 14 This is a schematic diagram of the flow velocity simulation results in the port region in the embodiments of this application;

[0045] Figure 15 This is a schematic diagram of the flow velocity simulation results at the straight air outlet in the embodiment of this application;

[0046] Figure 16 This is a schematic diagram of the flow velocity simulation results within the overall area of ​​the printing platform in this embodiment of the application.

[0047] Reference numerals: 1. Inlet tee unit; 11. Main air supply duct; 12. Upper outlet duct; 13. Lower outlet duct; 14. Sub-outlet; 2. Negative pressure exhaust unit; 21. Upper exhaust duct; 22. Lower exhaust duct; 23. Negative pressure tee; 24. Diversion grille; 25. Guide ramp; 3. Diversion grille assembly; 31. Horizontal grille; 32. Vertical grille; 33. First arc-shaped guide plate; 34. Second arc-shaped guide plate; 4. Guide pipe; 5. Airflow dispersion unit; 51. First vertical ramp; 52. Second vertical ramp; 53. Hole; 54. Reinforcing rib; 6. Straight air outlet; 7. Conical flow channel; 8. Decorative grille. Detailed Implementation

[0048] The following is in conjunction with the appendix Figure 1 -Appendix Figure 16 This application will be described in further detail.

[0049] This application discloses an airflow uniform distribution wind field system for a large-format additive manufacturing platform.

[0050] Reference Figure 1 and Figure 2 A wind field system for uniform airflow distribution in a large-format additive manufacturing platform includes an air inlet tee unit 1 and a negative pressure exhaust unit 2. The air inlet tee unit 1 consists of a main air supply pipe 11, an upper air outlet pipe 12, and a lower air outlet pipe 13. In this application, the main air supply pipe 11, the upper air outlet pipe 12, and the lower air outlet pipe 13 form a Y-shaped tee with one inlet and two outlets. The main air supply pipe 11 is a circular pipe with a tapered cross-section. Its smaller diameter end is connected to the air inlet of the upper air outlet pipe 12 and the lower air outlet pipe 13. The air outlets of the upper air outlet pipe 12 and the lower air outlet pipe 13 are square to accommodate the square processing area in the molding cavity. The connection between the main air supply pipe 11 and the upper air outlet pipe 12 and the lower air outlet pipe 13 is set with an arc transition. A square guide pipe 4 is connected to the air outlet end of the upper air outlet pipe 12 and the lower air outlet pipe 13. The other end of the guide pipe 4 is used to connect to the molding cavity.

[0051] Reference Figure 1 and Figure 2 In use, the airflow generated by the fan is first compressed and accelerated through the tapered main air supply duct 11 to ensure the airflow velocity into the upper air outlet duct 12 and the lower air outlet duct 13. During processing, the air inlet tee unit 1 is designed using A-grade curved surface standards for fluid dynamics. The curvature variation of the curved surface is controlled to ensure the smoothness of the zebra stripe pattern after forming meets the standards. Figure 3As shown, the uniformity and smoothness of the zebra stripe distribution on the curved surface of the upper air outlet duct 12 and the lower air outlet duct 13 must meet the Class A curved surface standard to reduce the flow resistance of the curved structure to the airflow. After being manufactured by 3D printing in one piece, the inner wall surface of the duct is then coated with a smooth coating to minimize the airflow resistance and ensure smooth airflow.

[0052] Reference Figure 2 and Figure 4 The connection opening size between the upper air outlet duct 12 and the main air supply duct 11 is smaller than the connection opening size between the lower air outlet duct 13 and the main air supply duct 11. In this embodiment, the cross-sectional area of ​​the air inlet of the upper air outlet duct 12 accounts for 15%-30% of the cross-sectional area of ​​the air outlet of the main air supply duct 11, preferably 30%. This design ensures that the gas flow rate delivered to the upper air outlet duct 12 is less than the gas flow rate delivered to the lower air outlet duct 13, thereby ensuring that the subsequent air flow rate delivered to the forming platform area is moderate, that is, minimizing the total input air flow rate while ensuring that the smoke and splashes generated during the printing process are discharged.

[0053] Reference Figure 4 and Figure 5 A diversion grille assembly 3 is also provided in the upper air outlet duct 12 and the lower air outlet duct 13. The diversion grille assembly 3 is used to initially distribute and guide the input airflow. The diversion grille assembly 3 is installed in the same way, in the same position and in the same way in the upper air outlet duct 12 and the lower air outlet duct 13. The lower air outlet duct 13 is used as an example for description: The diversion grille assembly 3 includes a horizontal grille plate 31, a vertical grille plate 32 and a first arc-shaped guide plate 33. The lengths of the horizontal grille plate 31, the vertical grille plate 32 and the first arc-shaped guide plate 33 all extend from the air inlet to the air outlet of the lower air outlet duct 13. The vertical grille plate 32 separates the inner flow channel of the lower air outlet duct 13 along the vertical middle, so that the two sides of the vertical grille plate 32 are symmetrically arranged.

[0054] Reference Figure 4 and Figure 5 The horizontal grille 31 separates the inner flow channel of the lower air outlet duct 13 in the horizontal direction, ensuring that the area of ​​the air inlet and air outlet of the lower air outlet duct 13 is divided into two parts. That is, at the air inlet and air outlet of the lower air outlet duct 13, the horizontal grille 31 and the vertical grille 32 are perpendicular to each other. In practical applications, different numbers of horizontal grilles 31 can be set according to the size of the air inlet and air outlet, so as to guide and divert the total airflow through several horizontal grilles 31, so as to ensure that the airflow in the inner flow channel of the lower air outlet duct 13 is more evenly distributed in each area.

[0055] Reference Figure 5 and Figure 6Multiple first arc-shaped guide plates 33 are provided, and the multiple first arc-shaped guide plates 33 are divided into two groups and symmetrically distributed on both sides of the vertical grid plate 32. A second arc-shaped guide plate 34 is also provided between two adjacent first arc-shaped guide plates 33. The length and curvature of the multiple second arc-shaped guide plates 34 are different. In this application, the length of the second arc-shaped guide plates 34 gradually increases along both sides of the vertical grid plate 32. The ends of the first arc-shaped guide plates 33 and the second arc-shaped guide plates 34 cooperate with the horizontal grid plate 31 and the vertical grid plate 32 to divide the air outlet of the lower air outlet 13 into multiple rectangular arrays of sub-air outlets 14. The opening size of the multiple sub-air outlets 14 is the same.

[0056] Reference Figure 4 and Figure 5 In use, the horizontal grille plate 31, the vertical grille plate 32, the first arc-shaped guide plate 33 and the second arc-shaped guide plate 34 work together to redistribute the airflow input from the single circular air inlet and guide the airflow to leave from the rectangular air outlet to cover the entire rectangular platform area. At the same time, due to the arc design of the air inlet tee unit 1, the airflow must turn during the flow process. Due to the inertia of the airflow, it is difficult to achieve uniform distribution by turning directly. Therefore, the first arc-shaped guide plate 33 and the second arc-shaped guide plate 34 are used to guide the flow path of the airflow, thereby improving the uniformity of the airflow volume from the multiple sub-air outlets 14.

[0057] Reference Figure 4 and Figure 7 To further improve the uniformity of airflow, an airflow dispersion unit 5 is provided inside the end of the guide pipe 4 near the sub-outlet 14. The airflow dispersion unit 5 is used to disperse and redistribute the airflow flowing out of the sub-outlet 14, thereby improving the uniformity of airflow distribution in this area. The airflow dispersion unit 5 is composed of several sets of triangular hollow plates. The several sets of triangular hollow plates are arranged in a rectangular linear array along the length of the air inlet of the guide pipe 4. In this embodiment, the number of triangular hollow plates is the same as the number of sub-outlets 14 arranged in the length direction of the air outlets of the lower air outlet 13 and the upper air outlet 12. That is, each set of triangular hollow plates corresponds to a set of sub-outlets 14. A set of sub-outlets 14 includes two sub-outlets 14 separated by a transverse grille plate 31.

[0058] Reference Figure 7 and Figure 8Each set of triangular perforated plates includes a first vertical inclined plate 51 and a second vertical inclined plate 52. The end of the first vertical inclined plate 51 away from the sub-air outlet 14 and the end of the second vertical inclined plate 52 away from the sub-air outlet 14 are fixedly connected together. The other ends of the first vertical inclined plate 51 and the second vertical inclined plate 52 are set with openings, and these openings are aligned with a set of sub-air outlets 14. That is, there is an included angle α between the first vertical inclined plate 51 and the second vertical inclined plate 52. The angle α is set between 15 degrees and 70 degrees. The specific value of α is adaptively adjusted according to the number of sub-air outlets 14 and the size of the opening. In this embodiment, α is preferably set to 30 degrees. The height of the first vertical inclined plate 51 and the second vertical inclined plate 52 is the same as the height of the inner channel of the guide pipe 4. Multiple perforated holes 53 are formed on the first vertical inclined plate 51 and the second vertical inclined plate 52. The hole shape of the perforated holes 53 can be square or honeycomb. In this embodiment, it is set to square holes.

[0059] Reference Figure 4 and Figure 7 When in use, the airflow from the sub-outlet 14 is a straight inertial airflow. Under the action of the angle structure between the first vertical inclined plate 51 and the second vertical inclined plate 52, the direction of part of the straight inertial airflow is deflected by the reflection effect of the inclined surface. At the same time, the setting of the hollow hole 53 allows another part of the straight inertial airflow to pass directly. Under the synergistic effect of the two, the straight inertial airflow flowing through the area can be effectively dispersed and the eddy phenomenon can be suppressed, thereby further improving the uniformity of the distribution of the subsequent airflow process. The inclination angle of the first vertical inclined plate 51 and the second vertical inclined plate 52, the density of the hollow hole 53 and the opening size need to be optimized and adjusted according to the simulation analysis or actual test results. The triangular hollow plate formed after adjustment is made by 3D printing.

[0060] Reference Figure 4 and Figure 7 Furthermore, the opening size and density of the perforated holes 53 in a set of airflow dispersion units 5 can be the same or different. In this application, the opening size of the perforated holes 53 on a first vertical inclined plate 51 and a second vertical inclined plate 52 located at both ends of the air inlet of the guide pipe 4 is larger, while the opening size of the perforated holes 53 in the middle area is smaller. Moreover, the distribution density of the perforated holes 53 in the edge area is less than that in the middle area. In addition, except for a first vertical inclined plate 51 and a second vertical inclined plate 52 on both sides, the opening size and density of the perforated holes 53 on all other first vertical inclined plates 51 and second vertical inclined plates 52 are the same. In actual use, since the airflow flowing through the guide pipe 4 is relatively concentrated in the middle area, that is, the airflow in the two edge areas is relatively small, the density design of the perforated holes 53 above makes the airflow in the middle area more fully dispersed, while the airflow dispersion effect on the edge is weaker, thereby ensuring that the airflow in the middle area and the edge area gradually becomes uniform after distribution.

[0061] Reference Figure 7 and Figure 8 In this application, in two adjacent sets of triangular perforated plates, the first vertical inclined plate 51 of one set of triangular perforated plates and the second vertical inclined plate 52 of the other set of triangular perforated plates are connected, that is, multiple triangular perforated plates of a set of airflow dispersion unit 5 are connected into a whole. At the same time, in order to further improve the structural strength of the airflow dispersion unit 5, a reinforcing rib 54 is connected between the adjacent first vertical inclined plate 51 and second vertical inclined plate 52. In use, the setting of the reinforcing rib 54 increases the structural strength of the entire airflow dispersion unit 5, thereby reducing the deformation of the triangular perforated plates during the airflow impact process.

[0062] Reference Figure 4 A straight air outlet 6 is formed on the inner wall of the end of the guide pipe 4 away from the airflow dispersion unit 5. Multiple straight air outlets 6 are arranged in a rectangular array. In this application, the straight air outlet 6 is a long, narrow rectangular hole. In other embodiments, the straight air outlet 6 can also be circular or honeycomb-shaped. A tapered flow channel 7 is provided between the air inlet of the straight air outlet 6 and the triangular hollow plate. The vertical cross-section of the tapered flow channel 7 is tapered, and the end with the smaller opening size faces the straight air outlet 6. In use, the application... According to Bernoulli's principle, the airflow, after being dispersed and redistributed by the airflow dispersion unit 5, is compressed and accelerated by the conical flow channel 7 and guided into the straight air outlet 6. Thus, the airflow is kept flowing at high speed and in a straight line through the slender straight air outlet 6, so as to stably sweep across the entire printing platform surface, achieving the effect of high-speed flow in the printing platform area with a small air volume. The small air volume reduces the fan speed requirement, thereby effectively reducing fan energy consumption and filter load, while also reducing the problems of fan bend vibration and overheating, and improving the operational stability of the equipment.

[0063] Reference Figure 2 and Figure 9 The negative pressure exhaust unit 2 is used to extract the protective airflow of the lens and the protective airflow of the printing area under negative pressure and re-converge them to guide the cyclone separator for filtration and recycling. The negative pressure exhaust unit 2 consists of an upper exhaust pipe 21, a lower exhaust pipe 22 and a negative pressure three-way pipe 23. The air inlets of the upper exhaust pipe 21 and the lower exhaust pipe 22 are rectangular and the air outlets are circular. The air inlet of the upper exhaust pipe 21 is set to correspond to the air outlet of the upper exhaust pipe 12, and the air inlet of the lower exhaust pipe 22 is set to correspond to the air outlet of the lower exhaust pipe 13. The air outlets of the upper exhaust pipe 21 and the lower exhaust pipe 22 are respectively connected to the two air inlets of the negative pressure three-way pipe 23. The air outlet of the negative pressure three-way pipe 23 is connected to the cyclone separator through an external ventilation pipe.

[0064] Reference Figure 2 and Figure 9In use, the airflow in the laser lens protection area is drawn through the upper exhaust pipe 21 and introduced into the negative pressure three-way pipe 23. The airflow in the forming platform protection area is drawn through the lower exhaust pipe 22 and poured into the negative pressure three-way pipe 23. Then, the two airflows are converged into one through the negative pressure three-way pipe 23 and poured into the cyclone separator. The cyclone separator intercepts and filters the smoke and dust and splashes carried in the airflow. The filtered airflow is guided to the external filtration system for secondary fine filtration. The filtration system can automatically perform back-flushing cleaning and inerting treatment based on the data of the differential pressure sensor, so as to collect the separated impurities into the ash bucket. The purified gas is finally delivered to the fan assembly, thus realizing recycling.

[0065] Reference Figure 9 and Figure 10 To ensure a uniform distribution of negative pressure in all areas of the flow channels within the upper exhaust duct 21 and lower exhaust duct 22, several diversion grid plates 24 are installed in both the upper exhaust duct 21 and lower exhaust duct 22. These diversion grid plates 24 are arranged in an array along the length of the air inlet end of the upper exhaust duct 21. In this embodiment, the diversion grid plates 24 are L-shaped, and the corners of the diversion grid plates 24 are arc-shaped. In use, the diversion grid plates 24 separate the flow channels within the upper exhaust duct 21 and lower exhaust duct 22, thereby ensuring a uniform distribution of negative pressure in all areas of the flow channels as much as possible. This allows for the suction of airflow in all areas of the molding cavity, while simultaneously guiding the sucked-in airflow stably into the negative pressure tee pipe 23, ensuring the effective discharge of airflow from the molding cavity.

[0066] Reference Figure 9 and Figure 10 In this embodiment, the outlet size of the upper exhaust pipe 21 is smaller than that of the lower exhaust pipe 22. In addition, a decorative grille plate 8 is provided at the air inlet of the upper exhaust pipe 21. The shape of the decorative grille plate 8 is the same as that of the air outlet of the guide pipe 4 corresponding to the upper exhaust pipe 12. That is, by setting the decorative grille plate 8, on the one hand, the negative pressure exhaust system is aesthetically pleasing, and on the other hand, it also has a simple filtration effect to prevent large particles from entering the upper exhaust pipe 21 and blocking the flow channel. A guide inclined plate 25 is integrally formed at the air inlet of the lower exhaust pipe 22. The bottom end of the guide inclined plate 25 is flush with the top surface of the molded matching. When in use, the setting of the guide inclined plate 25 guides the airflow to enter the lower exhaust pipe 22 normally. At the same time, some heavier powders on the molding platform are blocked by the guide inclined plate 25 to prevent the powders from being carried into the lower exhaust pipe 22 by the airflow, thereby reducing raw material waste and saving raw material costs.

[0067] Simulations were performed using fluid analysis software. A finite element model was established, and a fixed amount of airflow at a constant velocity was applied to the pipe. The simulated airflow trend is as follows: Figure 11 , Figure 12 , Figure 13 and Figure 14As shown, the closer the area is to the blue area, the smaller the airflow distribution in that area; the closer the area is to the red area, the more concentrated the airflow distribution in that area.

[0068] Reference Figure 11 and Figure 12 ,according to Figure 11 A comparison of the results shown in the three state diagrams (a, b, and c) reveals that as the curvature and length of the second arc-shaped guide vane 34 change, the airflow distribution within the arc-shaped flow channel also changes, until... Figure 11 In the state shown in diagram c, the length of the second arc-shaped guide vane 34 is relatively small, and the curvature is smoother, resulting in a more uniform airflow distribution within the flow channel; similarly... Figure 12 The three states a, b, and c correspond to respectively Figure 11 The flow velocity of the sub-outlet 14 in states a, b, and c is shown above. It can be seen from the above results that the length and curvature of the second arc-shaped guide plate 34 directly affect the uniformity of the airflow distribution. The structure disclosed in this embodiment is a structural design with relatively uniform airflow distribution.

[0069] Reference Figure 13 and Figure 14 In the figure, a1, b1, and c1 mainly reflect the airflow distribution state after the total airflow passes through the diversion grid assembly 3, the airflow dispersion unit 5, and the straight air outlet 6. a2, b2, and c2 mainly reflect the airflow distribution state at the port under the states of a1, b1, and c1. Comparing the three states, it can be seen that without the airflow dispersion unit 5, the airflow flowing out of the port is obviously concentrated in a region. After setting the airflow dispersion unit 5, the airflow distribution is relatively uniform. As the gap and density of the opening size of the hollow holes 53 on the airflow dispersion unit 5 increase, the airflow distribution also gradually becomes uniform. Among them, c1 and c2 are the simulation results corresponding to the airflow dispersion unit 5 in this embodiment.

[0070] Reference Figure 15 In the diagrams for states a, b, and c, it is evident that in state c, due to the absence of the airflow dispersion unit 5, there are significant differences in the airflow from the corresponding straight air outlets 6 in each region. In state b, the airflow dispersion unit 5 is added, resulting in a significant improvement in airflow distribution compared to state a, although some regions still experience insufficient airflow. In state a, the size and density of the perforations 53 in the airflow dispersion unit 5 are optimized, leading to a more uniform airflow distribution compared to state b, with the airflow distribution in each region gradually approaching the preset target. (Refer to...) Figure 16 This embodiment adopts a structural design of flow divider grid assembly 3, airflow dispersion unit 5, conical flow channel 7 and straight air outlet 6, which makes the airflow distribution in each area of ​​the entire printing platform more uniform and more conducive to use.

[0071] The implementation principle of this application embodiment is as follows: During use, the airflow is divided into the following stages:

[0072] Phase 1: The total airflow generated by the fan is divided into two paths after passing through the main air supply duct 11, and is delivered to the upper air outlet duct 12 and the lower air outlet duct 13 respectively to form the upper airflow and the lower airflow, wherein the flow rate of the upper airflow is less than the flow rate of the lower airflow.

[0073] Phase Two: Under the guidance and diversion of the diversion grid assembly 3, the upper and lower airflows are evenly distributed in various regions of the inner flow channels of the upper air outlet 12 and the lower air outlet 13. This redistributes the airflow from the single circular air inlet into multiple airflows, achieving initial dispersion of the uniform flow of the airflow. During this process, due to the guidance of the arc-shaped structures of the upper air outlet 12, the lower air outlet 13, the first arc-shaped guide plate 33, and the second arc-shaped guide plate 34, the airflow must turn during the flow process. Under the action of the airflow inertia, the airflow in each channel converges to form a straight inertial airflow, which flows out from the corresponding sub-air outlet 14. At the same time, the side with less airflow is prone to forming vortex phenomena.

[0074] Phase 3: When multiple straight inertial airflows pass through the airflow dispersion unit 5, part of the airflow impacts the first vertical inclined plate 51 and the second vertical inclined plate 52, and deflects its flow direction under the reflection of the inclined surface, thus mixing with the airflow in other areas and flowing out from its corresponding perforation 53. The other part of the airflow passes directly through the perforation 53. Under the synergistic effect of these two mechanisms, the straight inertial airflow flowing through this area is effectively dispersed and secondary distribution is carried out, further improving the uniformity of airflow distribution in each area of ​​the flow, and also effectively suppressing the generation of eddy phenomena.

[0075] Phase 4: Utilizing Bernoulli's principle, the airflow uniformly dispersed by the airflow dispersion unit 5 is compressed and accelerated through the conical flow channel 7 and then guided into the straight air outlet 6. Under the guidance of the straight air outlet 6, the airflow flows out, covering the entire rectangular platform area with a lower flow rate and a higher flow velocity. The airflow from the straight air outlet 6 corresponding to the upper air outlet duct 12 is transported to the laser lens protection area to form a lens protection airflow. The airflow from the straight air outlet 6 corresponding to the lower air outlet duct 13 is transported to the molding platform protection area to form a printing area protection airflow.

[0076] Phase 5: The upper exhaust pipe 21 and lower exhaust pipe 22, which are distributed vertically, work together to collect the protective airflow for the lens and the protective airflow for the printing area. During the collection process, the setting of multiple diversion grid plates 24 ensures that the suction negative pressure in the flow channels of the upper exhaust pipe 21 and lower exhaust pipe 22 is evenly distributed in each area, thereby ensuring the effective capture of smoke and unmelted particles.

[0077] Stage Six: The collected airflow is guided by the diversion grid plate 24, causing the rectangular cross-section airflow collected from the air inlets of the upper exhaust pipe 21 and the lower exhaust pipe 22 to gradually converge into a circular cross-section airflow, and then transported to the negative pressure tee pipe 23. During this process, the diversion grid plate 24 optimizes the turning path of the airflow, suppresses the generation of eddies, reduces the flow resistance of the airflow, and maintains the air pressure stability of the subsequent convergence process.

[0078] Stage 7: The two airflows collected by the upper exhaust pipe 21 and the lower exhaust pipe 22 are re-converged into one through the negative pressure three-way pipe 23, and then stably delivered to the cyclone separator for filtration and recycling. After that, the airflow filtered by the cyclone separator is subjected to secondary fine filtration through the filtration system. The separated impurities are collected in the ash bucket, and the purified airflow is reintroduced into the fan for secondary recycling.

[0079] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A wind field system for uniformly distributing airflow for a large-format additive manufacturing platform, characterized in that: The system includes an air inlet tee unit (1) and a negative pressure exhaust unit (2). The air inlet tee unit (1) includes a main air supply duct (11), an upper air outlet duct (12), and a lower air outlet duct (13). The connection between the main air supply duct (11), the upper air outlet duct (12), and the lower air outlet duct (13) is an arc transition. The opening size of the connection between the upper air outlet duct (12) and the main air supply duct (11) is smaller than the opening size of the connection between the lower air outlet duct (13) and the main air supply duct (11). Both the upper air outlet duct (12) and the lower air outlet duct (13) are equipped with a diversion grille assembly (3). The diversion grille assembly (3) divides the upper air outlet duct (12) into two sections. The air outlets of the upper air outlet (12) and the lower air outlet (13) are divided into several sub-air outlets (14) with the same opening size. A guide pipe (4) is provided at the air outlet of both the upper air outlet (12) and the lower air outlet (13). An airflow dispersion unit (5) is provided on one side of the guide pipe (4) near the sub-air outlet (14). A plurality of straight air outlet holes (6) arranged in an array are formed on the other side of the guide pipe (4). The airflow channel between the airflow dispersion unit (5) and the straight air outlet holes (6) is set as a conical flow channel (7) with a conical cross section. The smaller end of the conical flow channel (7) is set towards the straight air outlet hole (6). The airflow dispersion unit (5) is used to disperse the inertial airflow flowing out of the sub-outlet (14) and redistribute it so that it is evenly distributed in the conical flow channel (7). The conical flow channel (7) is used to compress and accelerate the dispersed airflow and introduce it into the straight air outlet (6). The airflow is then transported to the laser lens protection area and the forming platform protection area through the straight air outlet (6) to form the lens protection airflow and the printing area protection airflow. The negative pressure exhaust unit (2) is used to extract the lens protection airflow and the printing area protection airflow under negative pressure and re-converge them to the cyclone separator for filtration and recycling. The diversion grid assembly (3) includes a horizontal grid plate (31), a vertical grid plate (32), and a first arc-shaped guide plate (33). There are several first arc-shaped guide plates (33), which are distributed at intervals on both sides of the vertical grid plate (32). A second arc-shaped guide plate (34) is provided between two adjacent first arc-shaped guide plates (33). The length and curvature of the several second arc-shaped guide plates (34) are different.

2. The airflow uniform distribution wind field system for a large-format additive manufacturing platform according to claim 1, characterized in that: The airflow dispersion unit (5) includes several sets of triangular perforated plates arranged in a linear array. Adjacent sets of triangular perforated plates are fixedly connected. The triangular perforated plates include a first vertical inclined plate (51) and a second vertical inclined plate (52). The end of the first vertical inclined plate (51) away from the sub-air outlet (14) and the end of the second vertical inclined plate (52) away from the sub-air outlet (14) are fixedly connected. There is an included angle between the first vertical inclined plate (51) and the second vertical inclined plate (52). Both the first vertical inclined plate (51) and the second vertical inclined plate (52) are provided with perforated holes (53). In the straight inertial airflow flowing out of the sub-air outlet (14), part of the airflow is deflected under the action of the inclined surfaces of the first vertical inclined plate (51) and the second vertical inclined plate (52), and the other part of the airflow passes directly through the perforated holes (53).

3. The airflow uniform distribution wind field system for a large-format additive manufacturing platform according to claim 2, characterized in that: A reinforcing rib (54) connects the first vertical inclined plate (51) and the adjacent second vertical inclined plate (52).

4. The airflow uniform distribution wind field system for a large-format additive manufacturing platform according to claim 2, characterized in that: The size of the perforated holes (53) located at both ends of the airflow dispersion unit (5) is larger than the size of the perforated hole (53) located in the middle of the airflow dispersion unit (5).

5. The airflow uniform distribution wind field system for a large-format additive manufacturing platform according to claim 1, characterized in that: The negative pressure exhaust unit (2) includes an upper exhaust pipe (21), a lower exhaust pipe (22), and a negative pressure three-way pipe (23). The air inlet of the upper exhaust pipe (21) is correspondingly set with the air outlet of the upper exhaust pipe (12), and the air inlet of the lower exhaust pipe (22) is correspondingly set with the air outlet of the lower exhaust pipe (13). The air outlet of the upper exhaust pipe (21) and the air outlet of the lower exhaust pipe (22) are respectively connected to the two air inlets of the negative pressure three-way pipe (23). The air outlet of the negative pressure three-way pipe (23) is used to connect to the cyclone separator.

6. The airflow uniform distribution wind field system for a large-format additive manufacturing platform according to claim 5, characterized in that: Both the upper exhaust pipe (21) and the lower exhaust pipe (22) are equipped with a number of diversion grid plates (24). The number of diversion grid plates (24) are used to ensure that the negative pressure distribution of the air intake in each area of ​​the upper exhaust pipe (21) and the lower exhaust pipe (22) is uniform, and at the same time guide the airflow to enter the negative pressure tee pipe (23) stably.

7. The airflow uniform distribution wind field system for a large-format additive manufacturing platform according to claim 5, characterized in that: A decorative grille (8) is provided at the air inlet of the upper exhaust pipe (21).

8. The airflow uniform distribution wind field system for a large-format additive manufacturing platform according to claim 5, characterized in that: The air inlet of the lower exhaust pipe (22) is provided with a guide plate (25), and the lowest end of the guide plate (25) is flush with the top surface of the forming platform.

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