Flow field device for purifying printing cavity and 3D printer

Abstract

The utility model discloses a flow field device for purifying a printing cavity and a 3D printer, the flow field device comprises a forming cavity, an air inlet piece and an air outlet piece, the air inlet piece and the air outlet piece are communicated and arranged in the forming cavity, the air inlet piece and the air outlet piece are arranged away from each other, and the air inlet piece comprises an air inlet pipe and a lower air equalizing pipe connected to the air inlet pipe; the lower gas homogenizing pipe is arranged in the forming cavity in a communicating mode, the communicating position is located on the lower portion of the forming cavity, the outline of the edge of the end, away from the air inlet pipe, of the lower gas homogenizing pipe is rectangular, the long edge of the lower gas homogenizing pipe is parallel to the bottom wall of the forming cavity, a plurality of gas homogenizing plates are arranged in the lower gas homogenizing pipe, and a plurality of gas homogenizing holes are formed in the gas homogenizing plates. According to the utility model, a gas flow field can be formed near a laser scanning area, so that black smoke generated during laser scanning can be taken away comprehensively and effectively, and the influence of the black smoke on the printing quality in the printing process can be reduced.

Description

Technical Field

[0001] This utility model relates to the technical field of 3D printers, and in particular to a flow field device for purifying the printing cavity and a 3D printer. Background Technology

[0002] Additive manufacturing, also known as 3D printing, is an emerging manufacturing technology that uses digital models as a basis to build up materials layer by layer to create physical objects. Additive manufacturing equipment can directly construct solid parts "from scratch," without following the traditional processes of blanking, rough machining, and finishing, and without relying on specialized forming molds. It offers advantages such as design freedom, manufacturing flexibility, low cost, and short cycle times. Additive manufacturing technology has been widely applied in industries such as aerospace, automotive, machinery, energy, and medical for rapid development, rapid manufacturing, and rapid repair.

[0003] Laser powder bed fusion (LPBF) is one of the most common techniques in metal additive manufacturing. It uses a laser energy source to selectively fuse granular materials such as metals, ceramics, or polymers together according to a model to form a three-dimensional object. In existing metal 3D printers, when working, the laser scans the metal powder. The carbon elements, low-melting-point alloying elements, and impurity elements contained in the metal powder burn and vaporize, generating black smoke and impurity splatter within the forming cavity.

[0004] The black smoke inside the forming cavity can contaminate the powder bed and the optical path glass, especially during low-speed scanning when the laser energy input is high and the amount of black smoke generated is also large. After prolonged operation, a large amount of black smoke will adhere to the surface of the optical path glass. This will cause severe power attenuation when the laser passes through the optical path glass, and most of the laser energy will be absorbed by the optical path glass, resulting in rapid heating, overheating, or even cracking of the optical path glass. Furthermore, the contamination of the optical path glass by black smoke will also lead to insufficient power when the laser is incident on the metal powder, resulting in incomplete melting of the metal powder. In addition, if black smoke and impurities fall onto the surface of unprocessed metal powder, they will mix with the powder and contaminate the powder bed, thus affecting the production quality of laser processing. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a flow field device for purifying the printing cavity and a 3D printer, which can quickly and comprehensively expel the black smoke generated by laser scanning when the metal 3D printer is working, thereby reducing the impact of the black smoke generated by laser scanning on the printing quality.

[0006] To solve the above-mentioned technical problems, firstly, the flow field device for purifying a printing cavity provided by this utility model adopts the following technical solution:

[0007] A flow field device for purifying a printing cavity includes a forming cavity, an air inlet and an air outlet disposed on both sides of the forming cavity, both of which are connected to the forming cavity. The air inlet includes an air inlet pipe and a lower air distribution pipe connected to the air inlet pipe. The lower air distribution pipe is disposed at the lower part of the forming cavity and is connected to the forming cavity. The edge contour of the air outlet of the lower air distribution pipe away from the air inlet pipe is rectangular or elliptical, and its long side is parallel to the bottom wall of the forming cavity. A plurality of air distribution plates are disposed inside the lower air distribution pipe, arranged along the airflow direction, and each of the plurality of air distribution plates has a plurality of air distribution holes.

[0008] By adopting the above technical solution, airflow is introduced into the lower equalization pipe from the air inlet pipe. The airflow enters the forming cavity through the lower equalization pipe, which is the printing cavity. Because the lower equalization pipe has a rectangular outline at the end furthest from the air inlet pipe, with its long side parallel to the bottom wall of the forming cavity, it can disperse the concentrated, cylindrical airflow in the air inlet pipe into a rectangular airflow. This allows the airflow to pass more comprehensively and closely over the bottom wall of the forming cavity (laser scanning area), forming a gas flow field near the laser scanning area. This effectively removes the black smoke generated during laser scanning, thus reducing the impact of black smoke on print quality. Simultaneously, multiple equalization plates adjust the airflow distribution and speed, ensuring a uniform airflow distribution and increased velocity within the forming cavity. This results in a more uniform and stable airflow field within the forming cavity, further effectively removing black smoke and achieving a purification effect on the forming cavity.

[0009] Optionally, the long side of the lower air outlet is greater than or equal to the length of the laser scanning area of ​​the forming cavity.

[0010] Optionally, the air inlet pipe is also connected to an upper air distribution pipe. The outline of the upper air distribution pipe at the end away from the air inlet pipe is rectangular. The upper air distribution pipe is connected to the inside of the molding cavity and the connection point is located at the upper part of the molding cavity. Several air distribution plates are also provided inside the upper air distribution pipe.

[0011] While the gas flow field at the bottom of the forming cavity can remove most of the black smoke using the above technical solution, a small amount of black smoke will still escape to the top of the forming cavity. By splitting the airflow in the inlet duct through the upper and lower equalization pipes, and introducing airflow into the upper part of the forming cavity through the upper equalization pipe to form a gas flow field, the small amount of escaped black smoke will also be carried out of the forming cavity, further reducing the contamination of the laser channel glass by black smoke, thereby further improving the purification effect.

[0012] Optionally, the upper air equalization pipe has a first diversion mesh at its inlet end and the lower air equalization pipe has a second diversion mesh at its inlet end, wherein the mesh size of the first diversion mesh is greater than that of the second diversion mesh.

[0013] By adopting the above technical solution, since the black smoke is generated when the laser scans the metal powder, it is mainly concentrated in the lower part of the molding cavity. The first and second diversion meshes control the airflow entering the upper and lower equalization pipes. Because the mesh size of the first diversion mesh is larger than that of the second diversion mesh (i.e., the aperture of the first diversion mesh is smaller than that of the second diversion mesh), the airflow entering the upper equalization pipe is less than that entering the lower equalization pipe. This allows the airflow output from the lower equalization pipe to carry away most of the black smoke, while the airflow output from the upper equalization pipe carries away a small amount of black smoke that escapes to the upper part of the molding cavity.

[0014] Optionally, the diameter of the outlet end of the upper equalization pipe is smaller than the diameter of the outlet end of the lower equalization pipe.

[0015] By adopting the above technical solution, in order to adapt to the relatively small air flow in the upper equalization pipe, the diameter of the outlet end of the upper equalization pipe is set to be smaller than the diameter of the outlet end of the lower equalization pipe, so that the airflow output by the upper equalization pipe has sufficient flow velocity to effectively carry away the black smoke.

[0016] Optionally, the outlet end of the upper air equalization pipe is connected to an upper buffer pipe, and the outlet end of the lower air equalization pipe is connected to a lower buffer pipe. Both the upper and lower buffer pipes are located inside the molding cavity, and their ventilation paths are parallel to the bottom wall of the molding cavity.

[0017] By adopting the above technical solution, both the upper and lower buffer tubes are located within the forming cavity, thereby increasing the ventilation path length of the upper and lower gas equalization tubes within the forming cavity. This allows the air inlet to be closer to the laser scanning area and the laser channel glass, enabling the gas flow field to more effectively remove the black smoke from the laser scanning area and the laser channel glass. Simultaneously, the airflow after passing through the equalization plate enters the buffer tube for a certain degree of mixing, thus achieving buffering and pressure stabilization, further increasing the stability of the gas flow field within the forming cavity.

[0018] Optionally, both the upper and lower buffer tubes are equipped with jet plates at their air outlets. The jet plates have several rows of jet holes with triangular openings. Each pair of jet holes is staggered and arranged in a staggered manner.

[0019] By adopting the above technical solution, the opening profile of the jet orifice is triangular, and the two rows of jet orifices are staggered, which allows the jet plate to have a larger air outlet area. By installing jet plates with a larger air outlet area at the outlet ends of the upper and lower buffer pipes, the airflow can maintain a moderate velocity without affecting stability, avoiding excessively low airflow velocity. The triangular opening profile of the jet orifice also helps to stabilize the pressure of the flowing air.

[0020] Optionally, a flow field containment component is provided inside the molding cavity. The flow field containment component is in the shape of a square tube with its axis perpendicular to the bottom wall of the molding cavity. The buffer pipes of the upper and lower air equalization pipes and the air inlet of the air outlet are all connected to the internal space of the flow field containment component.

[0021] By adopting the above technical solution, the flow field containment component can reduce the size of the space where the gas flow field is located in the molding cavity, thereby making the gas flow field more concentrated and stable.

[0022] Optionally, the air outlet component includes a lower air outlet pipe connected to the molding cavity. The lower air outlet pipe has a rectangular opening edge and its long side is parallel to the bottom wall of the molding cavity. The ventilation paths of the lower air outlet pipe and the lower air distribution pipe are in the same horizontal direction.

[0023] By adopting the above technical solution, since the outline of the opening edge of the lower air outlet duct is rectangular and located in the same horizontal direction as the ventilation path of the lower air distribution duct, the airflow in the forming cavity carries black smoke into the lower air outlet duct, which is less likely to affect the stability of the gas flow field in the forming cavity.

[0024] Optionally, the air outlet component also includes a flow stabilizer connected to the lower air outlet duct. The flow stabilizer has a hollow internal structure, and the plane of the flow stabilizer parallel to the air outlet surface is triangular or trapezoidal. The lower air outlet duct is connected to the lower part of the forming cavity and the flow stabilizer. An air outlet is opened on the upper part of the flow stabilizer, and the air outlet is located on the center line of the lower air outlet duct.

[0025] By adopting the above technical solution, the exhaust gas is usually discharged through a pipe, and most pipes are designed with a circular cross-section. Therefore, the air outlet of the flow field device should usually be set in a circular pipe. In order to connect the circular cross-section pipe and the lower air outlet pipe with a rectangular opening edge, a flow stabilizer is installed. The flow stabilizer can transform the rectangular air outlet surface into a circle to facilitate the connection of the duct to discharge the exhaust gas. Since the air outlet is set on the centerline of the lower air outlet pipe, the distance from each air outlet point on the long side of the lower air outlet pipe to the air outlet is relatively closer. This reduces the difference in air velocity among the air outlet points on the long side of the lower air outlet pipe, thereby reducing the possibility that the gas flow field in the forming cavity will deform and fluctuate due to excessive air velocity differences, which would prevent the gas flow field from covering the entire laser scanning area and thus reduce the purification effect.

[0026] Optionally, an upper air outlet duct is provided between the flow stabilizer and the molding cavity, and the air passage paths of the upper air outlet duct and the upper air distribution duct are located in the same horizontal direction.

[0027] By adopting the above technical solution, the gas flow field in the upper part of the molding cavity is discharged from the upper air outlet pipe, thereby reducing the possibility of the upper airflow flowing to the lower air outlet pipe and causing instability and fluctuations in the lower gas flow field, and further increasing the overall stability of the gas flow field.

[0028] Secondly, the 3D printer provided by this utility model adopts the following technical solution:

[0029] A 3D printer includes the aforementioned flow field device for purifying the molding cavity.

[0030] In summary, this utility model has at least one of the following beneficial technical effects:

[0031] 1. The lower air distribution pipe disperses the concentrated, cylindrical airflow in the inlet pipe into a rectangular airflow, allowing the airflow to pass more comprehensively and closely over the bottom wall of the forming cavity (laser scanning area). This creates a gas flow field near the laser scanning area, effectively removing the black smoke generated during laser scanning and reducing its impact on print quality. Simultaneously, multiple air distribution plates adjust the airflow distribution and speed, ensuring a uniform airflow distribution and increased velocity within the forming cavity. This results in a more uniform and stable airflow field within the forming cavity, further enhancing the removal of black smoke and achieving effective purification of the forming cavity.

[0032] 2. By diverting the airflow in the air inlet pipe through the upper and lower equalization pipes, and then introducing the airflow into the upper part of the forming cavity through the upper equalization pipe to form a gas flow field, a small amount of escaping black smoke is also carried out of the forming cavity, further reducing the pollution of the laser channel glass by black smoke, thereby further improving the purification effect.

[0033] 3. The upper and lower buffer tubes can increase the ventilation path length of the upper and lower gas equalization tubes in the forming cavity, making the air inlet closer to the laser scanning area and the laser channel glass, so that the gas flow field can more effectively remove the black smoke in the laser scanning area and the laser channel glass; at the same time, the airflow after passing through the gas equalization plate enters the buffer tube for a certain degree of mixing, which can achieve buffering and pressure stabilization, further increasing the stability of the gas flow field in the forming cavity. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of the flow field device for purifying the printing cavity, which is a feature of this invention.

[0035] Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure along line AA.

[0036] Figure 3 This is a schematic diagram of the first structure of this utility model after the front baffle has been removed.

[0037] Figure 4 yes Figure 3 A magnified structural diagram of part B.

[0038] Figure 5 This is a schematic diagram of the second structure of this utility model after the front baffle has been removed.

[0039] Explanation of reference numerals in the attached drawings: 1. Molding cavity; 11. Light outlet hole; 12. Laser scanning area; 13. Flow field enclosure component; 14. Front baffle; 2. Lower air distribution pipe; 21. Second flow divider; 22. Lower buffer pipe; 3. Upper air distribution pipe; 31. First flow divider; 32. Upper buffer pipe; 4. Air distribution plate; 5. Air inlet pipe; 51. Anemometer; 6. Lower air outlet pipe; 7. Upper air outlet pipe; 8. Flow stabilizer; 81. Air outlet; 9. Jet plate; 91. Jet hole. Detailed Implementation

[0040] The following is in conjunction with the appendix Figure 1-5 The present invention will be described in further detail below.

[0041] This utility model discloses a flow field device for purifying a printing cavity. (Refer to...) Figure 1 The flow field device for purifying the printing cavity includes a forming cavity 1, an air inlet, and an air outlet. The forming cavity 1 is a hollow cuboid structure, and its internal space is the printing cavity. One side wall of the forming cavity 1 has an opening, and two vertical edges at the opening of the forming cavity 1 are provided with front baffles. The top wall of the forming cavity 1 has a light outlet hole 11 for mounting a laser emitter and a laser channel glass, and the bottom wall of the forming cavity 1 has a laser scanning area 12. The air inlet is located on one side wall of the forming cavity 1, and the air outlet is located on the side wall away from the air inlet.

[0042] Reference Figure 1 The air inlet assembly includes an air inlet pipe 5, a lower equalizing pipe 2, and an upper equalizing pipe 3. One end of the air inlet pipe 5 is the air inlet end, and the air outlet end of the air inlet pipe 5 is fixedly connected to a tee pipe by a clamp. The air inlet ends of the lower equalizing pipe 2 and the upper equalizing pipe 3 are respectively fixedly connected to the other two ends of the tee pipe by bends and clamps. An anemometer 51 is installed in the air inlet pipe 5 to monitor the air volume and air velocity of the air inlet pipe 5.

[0043] Reference Figure 1 and Figure 2The lower equalizing pipe 2 and the upper equalizing pipe 3 are both vertically fixed to the side wall of the molding cavity 1 and connected to the interior of the molding cavity 1. The lower equalizing pipe 2 is located at the lower part of the molding cavity 1, and the upper equalizing pipe 3 is located at the upper part of the molding cavity 1. Several equalizing plates 4 are fixedly installed inside the lower equalizing pipe 2 and the upper equalizing pipe 3. The equalizing plates 4 are perpendicular to the axis of the lower equalizing pipe 2 or the upper equalizing pipe 3, and have several equalizing holes. Since one end of the lower equalizing pipe 2 and the upper equalizing pipe 3 has a circular cross-section and the other end has a rectangular cross-section, and multiple equalizing plates 4 are installed inside, the lower equalizing pipe 2 and its equalizing plate 4, and the upper equalizing pipe 3 and its equalizing plate 4 are all formed by 3D printing during the processing and manufacturing of this application; the cross-section of the equalizing plate 4 is set as V-shaped and the tip is away from the molding cavity 1.

[0044] Airflow is introduced into the upper equalization pipe 3 and lower equalization pipe 2 through the air inlet pipe 5. The airflow enters the forming cavity 1 through these pipes. Since the lower equalization pipe 2 has a rectangular opening at the end furthest from the air inlet pipe 5, with its long side parallel to the bottom wall of the forming cavity 1, it disperses the concentrated, cylindrical airflow from the air inlet pipe into a rectangular airflow. This allows the airflow to pass more comprehensively and closely over the bottom wall of the forming cavity 1 (laser scanning area 12), forming a gas flow field near the laser scanning area 12. This effectively removes the black smoke generated during laser scanning, reducing the impact of black smoke on print quality. Simultaneously, multiple equalization plates 4 adjust the airflow distribution and speed, ensuring a uniform airflow distribution and increased velocity within the forming cavity 1. This results in a more uniform and stable airflow field within the forming cavity 1, further effectively removing black smoke and achieving a thorough purification of the forming cavity 1.

[0045] Although the gas flow field at the bottom of the forming cavity 1 can remove most of the black smoke, a small amount of black smoke will still escape to the top of the forming cavity 1. By splitting the airflow in the air inlet duct 5 through the upper equalization duct 3 and the lower equalization duct 2, and by introducing airflow into the upper part of the forming cavity 1 through the upper equalization duct 3 to form a gas flow field, the small amount of escaped black smoke will also be carried out of the forming cavity 1, further reducing the contamination of the laser channel glass by black smoke, thereby further improving the purification effect.

[0046] Reference Figure 2Since the black smoke is generated when the laser scans the metal powder, it mainly concentrates in the lower part of the forming cavity 1. The ends of the lower equalizing pipe 2 and the upper equalizing pipe 3 furthest from the inlet pipe 5 are the outlet ends. The outline of the outlet openings is rectangular, with its long side parallel to the bottom wall of the forming cavity 1. The diameter of the outlet end of the upper equalizing pipe 3 is smaller than that of the outlet end of the lower equalizing pipe 2. The inlet end of the upper equalizing pipe 3 is equipped with a first diverter mesh 31, and the inlet end of the lower equalizing pipe 2 is equipped with a second diverter mesh 21. The first diverter mesh 31 is perpendicular to the axis of the upper equalizing pipe 3, and the second diverter mesh 21 is perpendicular to the axis of the lower equalizing pipe 2. The mesh size of the first diverter mesh 31 is larger than that of the second diverter mesh 21.

[0047] The first diversion mesh 31 and the second diversion mesh 21 control the airflow entering the upper equalization pipe 3 and the lower equalization pipe 2. Since the mesh size of the first diversion mesh 31 is larger than that of the second diversion mesh 21 (i.e., the aperture of the first diversion mesh 31 is smaller than that of the second diversion mesh 21), the airflow entering the upper equalization pipe 3 is less than that entering the lower equalization pipe 2. This allows the airflow output from the lower equalization pipe 2 to carry away most of the black smoke, while the airflow output from the upper equalization pipe 3 carries away a small amount of black smoke that has escaped to the upper part of the forming cavity 1. The diameter of the outlet end of the upper equalization pipe 3 is set smaller than that of the outlet end of the lower equalization pipe 2 to accommodate the relatively small airflow in the upper equalization pipe 3, ensuring that the airflow output from the upper equalization pipe 3 also has sufficient velocity to effectively carry away the black smoke.

[0048] Reference Figure 2 and Figure 3 To stabilize the airflow output from the upper equalizing pipe 3 and the lower equalizing pipe 2, an upper buffer pipe 32 is fixedly connected to the outlet end of the upper equalizing pipe 3, and a lower buffer pipe 22 is fixedly connected to the outlet end of the lower equalizing pipe 2. Both the upper buffer pipe 32 and the lower buffer pipe 22 are located inside the molding cavity 1. The air passages of the upper buffer pipe 32 and the lower buffer pipe 22 are parallel to the bottom wall of the molding cavity 1. The opening edges of the upper buffer pipe 32 and the lower buffer pipe 22 are both rectangular, and their long sides are parallel to the bottom wall of the molding cavity 1. Multiple baffles are spaced apart along the long side of the opening edge inside the upper buffer pipe 32 and the lower buffer pipe 22. The multiple baffles are perpendicular to the bottom wall of the molding cavity 1. The upper buffer pipe 32 and the lower buffer pipe 22 of this application are both formed by 3D printing during processing and manufacturing.

[0049] Reference Figure 3 and Figure 4 Both the upper buffer pipe 32 and the lower buffer pipe 22 are equipped with jet plates 9 at their outlet ends. The jet plates 9 are vertically arranged on the axes of the upper buffer pipe 32 and the lower buffer pipe 22. Several rows of jet holes 91 are opened on the jet plates 9. The opening contour of the jet holes 91 is triangular, and every two rows of jet holes 91 are staggered and arranged.

[0050] Both the upper buffer tube 32 and the lower buffer tube 22 are located within the forming cavity 1, thereby increasing the ventilation path length of the upper equalizing tube 3 and the lower equalizing tube 2 within the forming cavity 1. This allows the air inlet to be closer to the laser scanning area 12 and the laser channel glass, enabling the gas flow field to more effectively remove the black smoke from the laser scanning area 12 and the laser channel glass. Simultaneously, the airflow after passing through the equalizing plate 4 enters the buffer tube for a certain degree of mixing, achieving buffering and pressure stabilization, further increasing the stability of the gas flow field within the forming cavity 1. The triangular opening profile of the jet orifice 91, with each row of jet orifices 91 staggered, allows the jet plate 9 to have a larger air outlet area. The jet plate 9 with a larger air outlet area at the outlet ends of the upper buffer tube 32 and the lower buffer tube 22 ensures that the airflow has a moderate velocity without affecting stability, avoiding excessively low airflow velocity. The triangular opening profile of the jet orifice 91 also helps to stabilize the flowing airflow.

[0051] Reference Figure 2 , Figure 3 and Figure 5 To further improve the stability of the gas flow field within the molding cavity 1, a flow field containment component 13 is installed inside the molding cavity 1. The flow field containment component 13 is a square tubular shape with its axis perpendicular to the bottom wall of the molding cavity 1. The buffer pipes of the upper gas equalization pipe 3 and the lower gas equalization pipe 2, as well as the air inlet of the air outlet, are all connected to the internal space of the flow field containment component 13. The flow field containment component 13 can reduce the size of the space where the gas flow field is located within the molding cavity 1, thereby making the gas flow field more concentrated and stable.

[0052] Reference Figure 1 and Figure 5 To ensure that the air outlet process does not affect the stability of the flow field within the forming cavity 1, the air outlet components include a lower air outlet pipe 6 and an upper air outlet pipe 7. The upper air outlet pipe 7 and the lower air outlet pipe 6 are fixedly installed on the side wall of the forming cavity 1 away from the lower equalizing pipe 2. Both the upper air outlet pipe 7 and the lower air outlet pipe 6 are connected to the internal space of the flow field enclosure component 13. The upper air outlet pipe 7 is located at the upper part of the forming cavity 1, and the lower air outlet pipe 6 is located at the lower part of the forming cavity 1. The opening edges of both the upper air outlet pipe 7 and the lower air outlet pipe 6 are rectangular, with their long sides parallel to the bottom wall of the forming cavity 1. The diameter of the upper air outlet pipe 7 is smaller than that of the lower air outlet pipe 6. The ventilation paths of the lower air outlet pipe 6 and the lower equalizing pipe 2 are located in the same horizontal direction, as are the ventilation paths of the upper air outlet pipe 7 and the lower equalizing pipe 2.

[0053] Since the opening edges of the lower exhaust duct 6 are all rectangular and located in the same horizontal direction as the ventilation path of the lower air duct 2, the airflow carrying black smoke into the molding cavity 1 is unlikely to affect the stability of the gas flow field within the molding cavity 1. Furthermore, the gas flow field in the upper part of the molding cavity 1 exits through the upper exhaust duct 7, thereby reducing the possibility of the upper airflow flowing down to the lower exhaust duct 6 and causing instability and fluctuations in the lower gas flow field, further increasing the overall stability of the gas flow field.

[0054] Reference Figure 1 , Figure 2 and Figure 5 Exhaust gas is typically discharged through pipes, most of which have a circular cross-section. Therefore, the outlet 81 of the flow field device should generally be located in a circular tube shape. To connect the circular cross-section pipes with the rectangular opening edges of the upper and lower outlet pipes 7 and 6, the air outlet component also includes a flow stabilizer 8. The flow stabilizer 8 has a hollow internal structure, and both the upper and lower outlet pipes 7 and 6 are fixedly connected to and communicate with the interior of the flow stabilizer 8. The plane of the flow stabilizer 8 parallel to the air outlet surface has a triangular or trapezoidal structure. In this embodiment, it is a trapezoidal structure, and the outlet 81 is located at the vertical centerline of the upper part of the flow stabilizer 8. The lower outlet pipe 6 is connected to the lower part of the flow stabilizer 8, and the upper outlet pipe 7 is connected to the upper part of the flow stabilizer 8. The upper part of the flow stabilizer 8 has an outlet 81, which is located on the centerline of the lower outlet pipe 6 and below the upper outlet pipe 7.

[0055] The flow stabilizer 8 can transform the rectangular air outlet surface into a circle, facilitating the connection of a duct to discharge the exhaust gas. Since the air outlet 81 is located on the centerline of the lower air outlet duct 6, the distance from each air outlet point on the long side of the lower air outlet duct 6 to the air outlet 81 is relatively closer, thus reducing the difference in air outlet rates at each air outlet point on the long side of the lower air outlet duct 6. This reduces the possibility that the gas flow field in the forming cavity 1 will deform and fluctuate due to excessive differences in air outlet rates, making it difficult for the gas flow field to cover the entire laser scanning area 12 and resulting in a deterioration in the purification effect.

[0056] The implementation principle of the flow field device for purifying the printing cavity according to this utility model embodiment is as follows: airflow is introduced into the upper air distribution pipe 3 and the lower air distribution pipe 2 from the air inlet pipe 5. The airflow enters the forming cavity 1 through the upper air distribution pipe 3 and the lower air distribution pipe 2. Since the opening edge of the lower air distribution pipe 2 away from the air inlet pipe 5 is rectangular and its long side is parallel to the bottom wall of the forming cavity 1, it can disperse the concentrated cylindrical airflow in the air inlet pipe into a rectangular airflow. This allows the airflow to pass through the bottom wall (laser scanning area 12) of the forming cavity 1 more comprehensively and at a closer distance, forming a gas flow field near the laser scanning area 12. This can comprehensively and effectively remove the black smoke generated during laser scanning, thereby reducing the impact of black smoke on printing quality during the printing process. Multiple air distribution plates 4 make the airflow entering the forming cavity 1 evenly distributed and increase the flow velocity, so that the airflow field formed in the forming cavity 1 is more uniform and stable, thereby more comprehensively and effectively removing black smoke and achieving an effective purification effect on the forming cavity 1.

[0057] By diverting the airflow in the air inlet duct 5 through the upper equalization duct 3 and the lower equalization duct 2, and then introducing the airflow into the upper part of the forming cavity 1 through the upper equalization duct 3 to form a gas flow field, a small amount of escaping black smoke is also carried out of the forming cavity 1, further reducing the pollution of the laser channel glass by the black smoke, thereby further improving the purification effect.

[0058] The above are all preferred embodiments of this utility model, and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape and principle of this utility model should be covered within the scope of protection of this utility model.

Claims

1. A flow field device for purifying a printing cavity, characterized in that: The utility model provides a kind of air supply device, including forming cavity (1), the air inlet piece and air outlet piece being arranged in the both sides of forming cavity (1), the air inlet piece and air outlet piece are communicated in forming cavity (1), the air inlet piece includes air inlet pipe (5) and the lower uniform air pipe (2) being connected to air inlet pipe (5), the lower uniform air pipe (2) is arranged in the lower portion of forming cavity (1) and is communicated in forming cavity (1), the edge profile of the air outlet of lower uniform air pipe (2) away from air inlet pipe (5) is rectangle or oval and its long side is parallel to the bottom wall of forming cavity (1), the lower uniform air pipe (2) is provided with several uniform air plates (4) being arranged along the air flow direction, and several uniform air plates (4) are provided with several uniform air holes.

2. The flow field device for purging a print chamber of claim 1, wherein: The air inlet pipe (5) is also connected with the upper uniform air pipe (3), the edge profile of the end of the upper uniform air pipe (3) away from air inlet pipe (5) is rectangle, the upper uniform air pipe (3) is communicated and arranged in the inside of forming cavity (1) and the communication place is in the upper portion of forming cavity (1), and the upper uniform air pipe (3) is also provided with several uniform air plates (4).

3. The flow field device for purging a print chamber of claim 2, wherein: The air inlet end of the upper uniform air pipe (3) is provided with the first shunt net (31), the air inlet end of the lower uniform air pipe (2) is provided with the second shunt net (21), and the mesh number of the first shunt net (31) is greater than that of the second shunt net (21).

4. The flow field device for purging a print cavity of claim 3, wherein: The caliber of the air outlet end of the upper uniform air pipe (3) is smaller than that of the air outlet end of the lower uniform air pipe (2).

5. The flow field device for purging a print chamber of claim 2, wherein: The air outlet end of the upper uniform air pipe (3) is connected with the upper buffer pipe (32), the air outlet end of the lower uniform air pipe (2) is connected with the lower buffer pipe (22), and the upper buffer pipe (32) and the lower buffer pipe (22) are both located in the forming cavity (1) and the air passage is parallel to the bottom wall of the forming cavity (1).

6. The flow field device for purging a print cavity of claim 5, wherein: The air outlet end of the upper buffer pipe (32) and the lower buffer pipe (22) is provided with the jet plate (9), the jet plate (9) is provided with several rows of jet holes (91), the opening profile of the jet hole (91) is triangular, and every two rows of jet holes (91) are staggered and matched.

7. The flow field device for purging a print cavity of claim 6, wherein: The flow field surrounding piece (13) is arranged in the forming cavity (1), the flow field surrounding piece (13) is square tubular and its axis is perpendicular to the bottom wall of the forming cavity (1), and the buffer pipe of the upper uniform air pipe (3) and the lower uniform air pipe (2) and the air inlet end of the air inlet piece are all communicated in the internal space of the flow field surrounding piece (13).

8. The flow field device for purging a print chamber of claim 1, wherein: The air inlet end of the air inlet piece is communicated and arranged in the lower air outlet pipe (6) of the forming cavity (1), the opening edge profile of the lower air outlet pipe (6) is rectangle and its long side is parallel to the bottom wall of the forming cavity (1), and the air passage of the lower air outlet pipe (6) and the lower uniform air pipe (2) is located in the same horizontal direction.

9. The flow field device for purging a print cavity of claim 8, wherein: The air inlet piece also includes the flow stabilizer (8) being connected to the lower air outlet pipe (6), the inside of the flow stabilizer (8) is hollow structure, the flow stabilizer (8) is parallel to the plane of the air outlet surface and is triangular or trapezoidal structure, the lower air outlet pipe (6) is connected to the lower portion of the forming cavity (1) and the flow stabilizer (8), the upper portion of the flow stabilizer (8) is provided with the air outlet (81), and the air outlet (81) is located on the center line of the lower air outlet pipe (6).

10. A 3D printer characterized by: A flow field device for purging a print chamber as claimed in any one of claims 1 to 9.

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