Flow field device for purifying printing cavity and 3D printer

Abstract

The invention 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 arranged in the forming cavity in a communicating mode, 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. The gas flow field can be formed near the laser scanning area, so that black smoke generated during laser scanning can be comprehensively and effectively taken away, and the influence of the black smoke on the printing quality in the printing process can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printers, and in particular to a flow field device for purifying a printing cavity and a 3D printer. Background Art

[0002] Additive manufacturing, also known as 3D printing, refers to an emerging manufacturing technology that uses digital models as the basis to stack materials layer by layer to create physical objects. Additive manufacturing equipment can directly build physical parts "from scratch" without following the traditional process of roughing, rough processing, and finishing, nor relying on special forming molds. It has the advantages of design freedom, manufacturing flexibility, low cost, and short cycle. Additive manufacturing technology has been widely used in aerospace, automotive, machinery, energy, medical and other industries for rapid development, rapid manufacturing, and rapid repair.

[0003] Laser powder bed fusion (LPBF) is one of the most common technologies 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. When existing metal 3D printers are working, the laser scans the metal powder. The carbon element, low-melting point alloy elements and impurity elements contained in the metal powder burn and gasify, generating black smoke and impurity splashes in the molding cavity.

[0004] The black smoke in the molding cavity will pollute the powder bed and the optical channel glass, especially when scanning at low speed, the laser energy input is large and the amount of black smoke generated is also large. After working for a long time, a large amount of black smoke will adhere to the surface of the optical channel glass, which will cause the laser power to attenuate seriously when passing through the optical channel glass, and most of the laser energy is absorbed by the optical channel glass, causing the optical channel glass to heat up quickly, get hot or even burst; and the pollution of the optical channel glass by black smoke will also cause insufficient power when the laser is incident on the metal powder, resulting in insufficient melting of the metal powder; further, black smoke and impurity splashes, such as falling on the surface of the unprocessed metal powder, mix with the powder, pollute the powder bed, and thus affect the production quality of laser processing. Summary of the invention

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

[0006] In order to solve the above technical problems, in a first aspect, the flow field device for purifying a printing cavity provided by the present invention adopts the following technical solutions:

[0007] A flow field device for purifying a printing cavity comprises a molding cavity, an air inlet member and an air outlet member arranged on both sides of the molding cavity, the air inlet member and the air outlet member are both connected to the molding cavity, the air inlet member comprises an air inlet pipe and a lower air equalizing pipe connected to the air inlet pipe, the lower air equalizing pipe is arranged at the lower part of the molding cavity and is connected to the molding cavity, the edge profile of the lower air equalizing pipe away from the air outlet of the air inlet pipe is rectangular or elliptical and its long side is parallel to the bottom wall of the molding cavity, a plurality of air equalizing plates arranged along the air flow direction are arranged in the lower air equalizing pipe, and a plurality of the air equalizing plates are each provided with a plurality of air equalizing holes.

[0008] By adopting the above technical solution, airflow is introduced from the air inlet pipe to the lower air equalizing pipe, and the airflow enters the interior of the molding cavity through the lower air equalizing pipe, and the interior of the molding cavity is the printing cavity. Since the contour of the edge of the end of the lower air equalizing pipe away from the air inlet pipe is rectangular and its long side is parallel to the bottom wall of the molding cavity, the concentrated and cylindrical airflow in the air inlet pipe can be dispersed to form a rectangular airflow, so that the airflow can pass through the bottom wall (laser scanning area) of the molding cavity more comprehensively and closely, that is, a gas flow field is formed near the laser scanning area, so that the black smoke generated during laser scanning can be taken away comprehensively and effectively, thereby reducing the impact of black smoke on the printing quality during the printing process. At the same time, the distribution and speed of the airflow are adjusted through multiple air equalizing plates, so that the airflow entering the molding cavity is evenly distributed and a certain flow rate is increased, so that the airflow field formed in the molding cavity is more uniform and stable, so that the black smoke can be taken away more comprehensively and effectively, and an effective purification effect is achieved on the molding cavity.

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

[0010] Optionally, the air inlet pipe is also connected to an upper air equalizing pipe, the outline of the edge of one end of the upper air equalizing pipe away from the air inlet pipe is rectangular, the upper air equalizing pipe is connected to the inside of the molding cavity and the connection point is located at the upper part of the molding cavity, and a plurality of air equalizing plates are also arranged in the upper air equalizing pipe.

[0011] By adopting the above technical solution, although the gas flow field at the lower part of the molding cavity can take away most of the black smoke, a small amount of black smoke will still escape to the upper part of the molding cavity. By dividing the airflow in the air inlet pipe through the upper air balancing pipe and the lower air balancing pipe, the airflow is introduced into the upper part of the molding cavity through the upper air balancing pipe to form a gas flow field, so as to take a small amount of escaped black smoke out of the molding cavity, further reducing the pollution of black smoke to the laser channel glass, thereby further improving the purification effect.

[0012] Optionally, a first flow-dividing net is provided at the air inlet end of the upper air-equalizing pipe, and a second flow-dividing net is provided at the air inlet end of the lower air-equalizing pipe, and the mesh number of the first flow-dividing net is greater than that of the second flow-dividing net.

[0013] By adopting the above technical solution, since black smoke is generated when the laser scans the metal powder, the black smoke is mainly concentrated in the lower part of the molding cavity. The first diverter net and the second diverter net control the amount of air entering the upper and lower air equalizing tubes. Since the mesh size of the first diverter net is larger than that of the second diverter net, that is, the aperture of the first diverter net is smaller than that of the second diverter net, the amount of air that can enter the upper air equalizing tube is smaller than that of the lower air equalizing tube, so that the airflow output by the lower air equalizing tube can take away most of the black smoke, and the airflow output by the upper air equalizing tube takes away a small amount of black smoke that escapes to the upper part of the molding cavity.

[0014] Optionally, the caliber of the air outlet end of the upper air balancing pipe is smaller than the caliber of the air outlet end of the lower air balancing pipe.

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

[0016] Optionally, the outlet end of the upper air equalizing pipe is connected to an upper buffer pipe, and the outlet end of the lower air equalizing pipe is connected to a lower buffer pipe. The upper buffer pipe and the lower buffer pipe are both located in the molding cavity and the ventilation paths are parallel to the bottom wall of the molding cavity.

[0017] By adopting the above technical solution, the upper buffer tube and the lower buffer tube are both located in the molding cavity, so that the ventilation path length of the upper gas equalizing tube and the lower gas equalizing tube in the molding cavity can be increased, so that the air inlet end is closer to the laser scanning area and the laser channel glass, so that the gas flow field can more effectively take away the black smoke in the laser scanning area and the laser channel glass. At the same time, the airflow after passing through the gas equalizing plate enters the buffer tube for a certain degree of mixing, so that it can be buffered and stabilized, further increasing the stability of the gas flow field in the molding cavity.

[0018] Optionally, the air outlet ends of the upper buffer tube and the lower buffer tube are both provided with jet plates, and the jet plates are provided with a plurality of rows of jet holes, the opening contours of the jet holes are triangular, and every two rows of the jet holes are arranged in an alternating manner.

[0019] By adopting the above technical solution, the opening contour of the jet hole is triangular and every two rows of jet holes are arranged in an interlaced manner, so that the jet plate can have a larger air outlet area. Jet plates with a larger air outlet area are arranged at the air outlet ends of the upper buffer tube and the lower buffer tube, so that the airflow can have a moderate flow rate without affecting the stability, avoiding the situation where the airflow velocity is too low. The opening contour of the jet hole is triangular, which can also play a role in stabilizing the pressure of the airflow passing through.

[0020] Optionally, a flow field enclosure is arranged in the molding cavity, and the flow field enclosure is in the shape of a square tube and its axis is perpendicular to the bottom wall of the molding cavity, and the buffer tubes of the upper and lower air equalizing pipes and the air inlet ends of the air outlet pieces are connected to the internal space of the flow field enclosure.

[0021] By adopting the above technical solution, the flow field enclosure 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 opening edge contour of the lower air outlet pipe is rectangular and its long side is parallel to the bottom wall of the molding cavity, and the ventilation paths of the lower air outlet pipe and the lower air equalizing pipe are located in the same horizontal direction.

[0023] By adopting the above technical solution, since the edge contours of the opening of the lower air outlet duct are rectangular and are located in the same horizontal direction as the ventilation path of the lower air duct, the airflow in the molding cavity carries black smoke into the lower air outlet duct, which is not easy to affect the stability of the gas flow field in the molding cavity.

[0024] Optionally, the air outlet component also includes a flow stabilizer connected to the lower air outlet duct, the interior of the flow stabilizer is a hollow structure, and the flow stabilizer is a triangular or trapezoidal structure in a plane parallel to the air outlet surface. The lower air outlet duct is connected to the molding cavity and the lower part of the flow stabilizer, and 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. Most of the pipes are set to a circular cross-section, so the air outlet of the flow field device should usually be set in a circular tube shape. In order to connect the pipe with a circular cross-section and the lower air outlet pipe with a rectangular opening edge contour, a flow stabilizer is provided. The flow stabilizer can change the rectangular air outlet surface into a circle, so as to facilitate the connection duct to discharge the exhaust gas. Since the air outlet is set on the center line 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, so that the difference in air outlet velocity between each air outlet point on the long side of the lower air outlet pipe becomes smaller, thereby reducing the possibility that the gas flow field in the molding cavity is deformed and fluctuated due to the large difference in air outlet velocity, which makes it difficult for the gas flow field to cover the entire laser scanning area and the purification effect deteriorates.

[0026] Optionally, an upper air outlet pipe is provided between the flow stabilizer and the forming cavity, and the ventilation paths of the upper air outlet pipe and the upper air equalizing pipe are located in the same horizontal direction.

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

[0028] In a second aspect, the 3D printer provided by the present invention adopts the following technical solution:

[0029] A 3D printer comprises the above-mentioned flow field device for purifying a molding cavity.

[0030] In summary, the present invention includes at least one of the following beneficial technical effects:

[0031] 1. The lower air equalizing pipe disperses the concentrated and cylindrical airflow in the air inlet pipe to form a rectangular airflow, so that the airflow can pass through the bottom wall (laser scanning area) of the molding cavity more comprehensively and closely, that is, a gas flow field is formed near the laser scanning area, so that the black smoke generated during laser scanning can be fully and effectively taken away, thereby reducing the impact of black smoke on the printing quality during the printing process; at the same time, the distribution and speed of the airflow are adjusted through multiple air equalizing plates, so that the airflow entering the molding cavity is evenly distributed and a certain flow rate is increased, so that the airflow field formed in the molding cavity is more uniform and stable, so that the black smoke can be taken away more comprehensively and effectively, and the molding cavity can be effectively purified;

[0032] 2. By dividing the air flow in the air inlet pipe through the upper air balancing pipe and the lower air balancing pipe, the air flow is introduced into the upper part of the molding cavity through the upper air balancing pipe to form a gas flow field, so as to bring a small amount of escaped black smoke out of the molding cavity, further reducing the pollution of black smoke to the laser channel glass, thereby further improving the purification effect;

[0033] 3. The upper buffer tube and the lower buffer tube can increase the ventilation path length of the upper air equalizing tube and the lower air equalizing tube in the molding cavity, so that the air inlet end is closer to the laser scanning area and the laser channel glass, so that the gas flow field can more effectively take away the black smoke in the laser scanning area and the laser channel glass; at the same time, the airflow after passing through the air equalizing plate enters the buffer tube for a certain degree of mixing, which can be buffered and stabilized, further increasing the stability of the gas flow field in the molding cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the overall structure of the flow field device used to purify the printing cavity of the present invention.

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

[0036] Figure 3 It is a first structural schematic diagram of the present invention after the front baffle is removed.

[0037] Figure 4 yes Figure 3 Schematic diagram of the enlarged structure of part B.

[0038] Figure 5 It is a second structural schematic diagram of the present invention after the front baffle is removed.

[0039] Explanation of the reference numerals in the accompanying drawings: 1. Molding cavity; 11. Light outlet hole; 12. Laser scanning area; 13. Flow field enclosure; 14. Front baffle; 2. Lower air equalizing pipe; 21. Second flow distribution net; 22. Lower buffer pipe; 3. Upper air equalizing pipe; 31. First flow distribution net; 32. Upper buffer pipe; 4. Air equalizing 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 DESCRIPTION

[0040] The following is combined with Figure 1-5 The present invention is described in further detail.

[0041] The embodiment of the present invention discloses a flow field device for purifying a printing chamber. Figure 1 The flow field device for purifying the printing cavity includes a molding cavity 1, an air inlet and an air outlet. The molding cavity 1 is a hollow rectangular structure. The internal space of the molding cavity 1 is a printing cavity. One side wall of the molding cavity 1 is opened, and two vertical edges of the opening of the molding cavity 1 are provided with a front baffle. The top wall of the molding cavity 1 is provided with a light outlet hole 11 for installing a laser emitter and a laser channel glass. The bottom wall of the molding cavity 1 is provided with a laser scanning area 12. The air inlet is provided on one side wall of the molding cavity 1, and the air outlet is provided on a side wall away from the air inlet.

[0042] Reference Figure 1 The air inlet part includes an air inlet pipe 5, a lower air balancing pipe 2 and an upper air balancing pipe 3. One end of the air inlet pipe 5 is an air inlet end. The air outlet end of the air inlet pipe 5 is fixed with a tee pipe through a clamp. The air inlet ends of the lower air balancing pipe 2 and the upper air balancing pipe 3 are respectively fixedly connected to the other two end pipe openings of the tee pipe through a bend pipe and a clamp. The air inlet pipe 5 is provided with an anemometer 51 for monitoring the air inlet volume and air inlet velocity of the air inlet pipe 5.

[0043] Reference Figure 1 and Figure 2, the lower air equalizing tube 2 and the upper air equalizing tube 3 are both vertically fixed to the side wall of the molding cavity 1 and connected to the inside of the molding cavity 1, the lower air equalizing tube 2 is arranged at the lower part of the molding cavity 1, and the upper air equalizing tube 3 is arranged at the upper part of the molding cavity 1. Several air equalizing plates 4 are fixedly arranged in the lower air equalizing tube 2 and the upper air equalizing tube 3, and the air equalizing plates 4 are perpendicular to the axis of the lower air equalizing tube 2 or the upper air equalizing tube 3, and the air equalizing plates 4 are provided with several air equalizing holes. Since one end of the lower air equalizing tube 2 and the upper air equalizing tube 3 is a circular cross-section and the other end is a rectangular cross-section, and multiple air equalizing plates 4 are arranged inside, the lower air equalizing tube 2 and its air equalizing plates 4, the upper air equalizing tube 3 and its air equalizing plates 4 of the present application are formed by 3D printing as a whole during processing and manufacturing; to facilitate 3D printing, the cross-section of the air equalizing plate 4 is set to be V-shaped and the tip is away from the molding cavity 1.

[0044] Airflow is introduced from the air inlet pipe 5 into the upper air equalizing pipe 3 and the lower air equalizing pipe 2, and the airflow enters the molding cavity 1 through the upper air equalizing pipe 3 and the lower air equalizing pipe 2. Since the edge contour of the opening of the lower air equalizing pipe 2 at one end away from the air inlet pipe 5 is rectangular and its long side is parallel to the bottom wall of the molding cavity 1, the concentrated and cylindrical airflow in the air inlet pipe can be dispersed to form a rectangular airflow, so that the airflow can pass through the bottom wall (laser scanning area 12) of the molding cavity 1 more comprehensively and closely, that is, a gas flow field is formed near the laser scanning area 12, so that the black smoke generated during laser scanning can be fully and effectively taken away, thereby reducing the impact of black smoke on the printing quality during the printing process. At the same time, the distribution and speed of the airflow are adjusted through multiple air equalizing plates 4, so that the airflow entering the molding cavity 1 is evenly distributed and a certain flow rate is increased, so that the airflow field formed in the molding cavity 1 is more uniform and stable, so that the black smoke can be taken away more comprehensively and effectively, and the molding cavity 1 can achieve an effective purification effect.

[0045] Although the gas flow field at the bottom of the molding cavity 1 can take away most of the black smoke, a small amount of black smoke will still escape to the upper part of the molding cavity 1. By diverting the airflow in the air inlet pipe 5 through the upper air balancing pipe 3 and the lower air balancing pipe 2, the airflow is introduced into the upper part of the molding cavity 1 through the upper air balancing pipe 3 to form a gas flow field, so that a small amount of escaped black smoke can also be taken out of the molding cavity 1, further reducing the pollution of the laser channel glass by black smoke, thereby further improving the purification effect.

[0046] Reference Figure 2Since black smoke is generated when the laser scans the metal powder, the black smoke is mainly concentrated in the lower part of the molding cavity 1. The openings at one end of the lower air equalizing pipe 2 and the upper air equalizing pipe 3 away from the air inlet pipe 5 are the air outlet ends. The contours of the opening edges of the air outlet ends are rectangular and their long sides are parallel to the bottom wall of the molding cavity 1. The caliber of the air outlet end of the upper air equalizing pipe 3 is smaller than the caliber of the air outlet end of the lower air equalizing pipe 2. The air inlet end of the upper air equalizing pipe 3 is provided with a first diverter net 31, and the air inlet end of the lower air equalizing pipe 2 is provided with a second diverter net 21. The first diverter net 31 is perpendicular to the axis of the upper air equalizing pipe 3, and the second diverter net 21 is perpendicular to the axis of the lower air equalizing pipe 2. The mesh number of the first diverter net 31 is greater than that of the second diverter net 21.

[0047] The first flow-dividing net 31 and the second flow-dividing net 21 control the amount of air entering the upper air-equalizing tube 3 and the lower air-equalizing tube 2. Since the mesh number of the first flow-dividing net 31 is larger than that of the second flow-dividing net 21, that is, the aperture of the first flow-dividing net 31 is smaller than that of the second flow-dividing net 21, the amount of air entering the upper air-equalizing tube 3 is smaller than that of the lower air-equalizing tube 2, so that the airflow output by the lower air-equalizing tube 2 can take away most of the black smoke, and then the airflow output by the upper air-equalizing tube 3 takes away a small amount of black smoke escaping to the upper part of the molding cavity 1. The caliber of the air outlet end of the upper air-equalizing tube 3 is set to be smaller than the caliber of the air outlet end of the lower air-equalizing tube 2 to adapt to the relatively small amount of airflow in the upper air-equalizing tube 3, so that the airflow output by the upper air-equalizing tube 3 can also have a sufficient flow rate to effectively take away the black smoke.

[0048] Reference Figure 2 and Figure 3 In order to make the airflow output by the upper and lower air equalizing tubes 3 and 2 more stable, the air outlet end of the upper and lower air equalizing tubes 3 is fixedly connected with the upper buffer tube 32, and the air outlet end of the lower and lower air equalizing tubes 2 is fixedly connected with the lower buffer tube 22. The upper and lower buffer tubes 32 and 22 are both located in the molding cavity 1. The ventilation paths of the upper and lower buffer tubes 32 and 22 are parallel to the bottom wall of the molding cavity 1. The opening edge contours of the upper and lower buffer tubes 32 and 22 are both rectangular and their long sides are parallel to the bottom wall of the molding cavity 1. Multiple partitions are arranged in the upper and lower buffer tubes 32 and 22 along the long side direction of the opening edge, and the multiple partitions are perpendicular to the bottom wall of the molding cavity 1. The upper and lower buffer tubes 32 and 22 of the present application are formed by 3D printing as a whole during processing and manufacturing.

[0049] Reference Figure 3 and Figure 4 The outlet ends of the upper buffer tube 32 and the lower buffer tube 22 are both provided with jet plates 9, which are arranged perpendicularly to the axes of the upper buffer tube 32 and the lower buffer tube 22. The jet plates 9 are provided with a plurality of rows of jet holes 91, the opening profile of the jet holes 91 is triangular, and every two rows of jet holes 91 are arranged in an interlaced manner.

[0050] The upper buffer tube 32 and the lower buffer tube 22 are both located in the molding cavity 1, so that the ventilation path length of the upper gas equalizing tube 3 and the lower gas equalizing tube 2 in the molding cavity 1 can be increased, so that the air inlet end is closer to the laser scanning area 12 and the laser channel glass, so that the gas flow field can more effectively take away the black smoke at the laser scanning area 12 and the laser channel glass. At the same time, the airflow after passing through the gas equalizing plate 4 enters the buffer tube for a certain degree of mixing, so that it can be buffered and stabilized, further increasing the stability of the gas flow field in the molding cavity 1. The opening contour of the jet hole 91 is triangular and every two rows of jet holes 91 are staggered and arranged, so that the jet plate 9 has a larger air outlet area. A jet plate 9 with a larger air outlet area is set at the air outlet end of the upper buffer tube 32 and the lower buffer tube 22, so that the airflow can have a moderate flow rate without affecting the stability, avoiding the situation where the airflow velocity is too small. The opening contour of the jet hole 91 is triangular, and it can also play a role in stabilizing the pressure of the airflow passing through.

[0051] Reference Figure 2 , Figure 3 and Figure 5 In order to further improve the stability of the gas flow field in the molding cavity 1, a flow field enclosure 13 is provided in the molding cavity 1. The flow field enclosure 13 is in a square tube shape and its axis is perpendicular to the bottom wall of the molding cavity 1. The buffer tubes and the air inlet ends of the air outlets of the upper and lower gas equalizing pipes 3 and 2 are connected to the internal space of the flow field enclosure 13. The flow field enclosure 13 can reduce the size of the space where the gas flow field in the molding cavity 1 is located, thereby making the gas flow field more concentrated and stable.

[0052] Reference Figure 1 and Figure 5 In order to ensure that the air outlet process does not affect the stability of the flow field in the molding cavity 1, the air outlet part includes a lower air outlet duct 6 and an upper air outlet duct 7. The upper air outlet duct 7 and the lower air outlet duct 6 are fixedly installed on the side wall of the molding cavity 1 away from the lower air equalizing pipe 2. The upper air outlet duct 7 and the lower air outlet duct 6 are both connected to the internal space of the flow field enclosure 13. The upper air outlet duct 7 is arranged at the upper part of the molding cavity 1, and the lower air outlet duct 6 is arranged at the lower part of the molding cavity 1. The opening edge contours of the upper air outlet duct 7 and the lower air outlet duct 6 are both rectangular and their long sides are parallel to the bottom wall of the molding cavity 1. The caliber of the upper air outlet duct 7 is smaller than that of the lower air outlet duct 6; the ventilation paths of the lower air outlet duct 6 and the lower air equalizing pipe 2 are located in the same horizontal direction, and the ventilation paths of the upper air outlet duct 7 and the lower air equalizing pipe 2 are located in the same horizontal direction.

[0053] Since the edge contours of the opening of the lower air outlet pipe 6 are rectangular and are located in the same horizontal direction as the ventilation path of the lower air outlet pipe 2, the airflow in the molding cavity 1 carries black smoke into the lower air outlet pipe 6, which is not likely to affect the stability of the gas flow field in the molding cavity 1. In addition, the gas flow field in the upper part of the molding cavity 1 is discharged from the upper air outlet pipe 7, thereby reducing the possibility that the upper airflow flows to the lower air outlet pipe 6 and causes 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 , the exhaust gas is usually discharged through a pipe, and most of the pipes are set to a circular cross-section, so the air outlet 81 of the flow field device should usually be set in a circular tube shape. In order to connect the pipe with a circular cross-section and the upper air outlet duct 7 and the lower air outlet duct 6 with a rectangular opening edge contour, the air outlet member also includes a flow stabilizer 8, the interior of the flow stabilizer 8 is a hollow structure, and the upper air outlet duct 7 and the lower air outlet duct 6 are fixedly connected to the flow stabilizer 8 and connected to the interior of the flow stabilizer 8. The flow stabilizer 8 is parallel to the plane of the air outlet surface and has a triangular or trapezoidal structure. In the embodiment of the present application, it is a trapezoidal structure. An air outlet 81 is provided at the vertical center line of the upper part of the flow stabilizer 8. The lower air outlet duct 6 is connected to the lower part of the flow stabilizer 8, and the upper air outlet duct 7 is connected to the upper part of the flow stabilizer 8. An air outlet 81 is opened at the upper part of the flow stabilizer 8, and the air outlet 81 is located on the center line of the lower air outlet duct 6, and the air outlet 81 is located below the upper air outlet duct 7.

[0055] The flow stabilizer 8 can change the rectangular air outlet surface into a circular shape so as to facilitate the connection duct to guide the exhaust gas out. Since the air outlet 81 is arranged on the center line of the lower air outlet pipe 6, the distance between each air outlet point on the long side of the lower air outlet pipe 6 and the air outlet 81 is relatively closer, so that the difference in air outlet speed between each air outlet point on the long side of the lower air outlet pipe 6 becomes smaller, thereby reducing the possibility that the gas flow field in the molding cavity 1 is deformed and fluctuated due to the large difference in air outlet speed, which makes it difficult for the gas flow field to cover the entire laser scanning area 12, and the purification effect becomes poor.

[0056] The implementation principle of a flow field device for purifying a printing cavity in an embodiment of the present invention is as follows: airflow is introduced from the air inlet pipe 5 into the upper air equalizing pipe 3 and the lower air equalizing pipe 2, and the airflow enters the molding cavity 1 through the upper air equalizing pipe 3 and the lower air equalizing pipe 2. Since the edge contour of the opening of the lower air equalizing pipe 2 at one end away from the air inlet pipe 5 is rectangular and its long side is parallel to the bottom wall of the molding cavity 1, the concentrated and cylindrical airflow in the air inlet pipe can be dispersed to form a rectangular airflow, so that the airflow can pass through the bottom wall (laser scanning area 12) of the molding cavity 1 more comprehensively and closely, and form a gas flow field near the laser scanning area 12, so as to be able to comprehensively and effectively take away the black smoke generated during laser scanning, thereby reducing the influence of black smoke on the printing quality during the printing process. Multiple air equalizing plates 4 make the airflow entering the molding cavity 1 evenly distributed and increase a certain flow rate, so that the airflow field formed in the molding cavity 1 is more uniform and stable, so that the black smoke can be taken away more comprehensively and effectively, and the molding cavity 1 can achieve an effective purification effect.

[0057] By diverting the air flow in the air inlet pipe 5 through the upper air equalizing pipe 3 and the lower air equalizing pipe 2, the air flow is introduced into the upper part of the molding cavity 1 through the upper air equalizing pipe 3 to form a gas flow field, so that a small amount of escaping black smoke is also brought out of the molding cavity 1, further reducing the pollution of the black smoke to the laser channel glass, thereby further improving the purification effect.

[0058] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A flow field device for purifying a printing cavity, characterized in that: The invention comprises a molding cavity (1), an air inlet member and an air outlet member arranged on both sides of the molding cavity (1), wherein the air inlet member and the air outlet member are both connected to the molding cavity (1), the air inlet member comprises an air inlet pipe (5) and a lower air equalizing pipe (2) connected to the air inlet pipe (5), the lower air equalizing pipe (2) is arranged at the lower part of the molding cavity (1) and is connected to the molding cavity (1), the edge contour of the air outlet of the lower air equalizing pipe (2) away from the air inlet pipe (5) is rectangular or elliptical and its long side is parallel to the bottom wall of the molding cavity (1), and a plurality of air equalizing plates (4) arranged along the air flow direction are arranged in the lower air equalizing pipe (2), and a plurality of air equalizing holes are opened on the plurality of air equalizing plates (4).

2. A flow field device for purifying a printing chamber according to claim 1, characterized in that: The air inlet pipe (5) is also connected to an upper air equalizing pipe (3), and the outline of the edge of one end of the upper air equalizing pipe (3) away from the air inlet pipe (5) is rectangular. The upper air equalizing pipe (3) is connected to the inside of the molding cavity (1) and the connection point is located at the upper part of the molding cavity (1). A plurality of air equalizing plates (4) are also arranged in the upper air equalizing pipe (3).

3. A flow field device for purifying a printing chamber according to claim 2, characterized in that: The air inlet end of the upper air balancing pipe (3) is provided with a first flow dividing net (31), and the air inlet end of the lower air balancing pipe (2) is provided with a second flow dividing net (21), and the mesh number of the first flow dividing net (31) is greater than that of the second flow dividing net (21).

4. A flow field device for purifying a printing chamber according to claim 3, characterized in that: The caliber of the gas outlet end of the upper gas equalizing pipe (3) is smaller than the caliber of the gas outlet end of the lower gas equalizing pipe (2).

5. A flow field device for purifying a printing chamber according to claim 2, characterized in that: The air outlet end of the upper air equalizing pipe (3) is connected to an upper buffer pipe (32), and the air outlet end of the lower air equalizing pipe (2) is connected to a lower buffer pipe (22). Both the upper buffer pipe (32) and the lower buffer pipe (22) are located in the molding cavity (1), and the ventilation paths are parallel to the bottom wall of the molding cavity (1).

6. A flow field device for purifying a printing chamber according to claim 5, characterized in that: The air outlet ends of the upper buffer tube (32) and the lower buffer tube (22) are both provided with a jet plate (9), and the jet plate (9) is provided with a plurality of rows of jet holes (91), the opening profile of the jet holes (91) is triangular, and every two rows of the jet holes (91) are arranged in a staggered manner.

7. A flow field device for purifying a printing chamber according to claim 6, characterized in that: A flow field enclosure (13) is arranged in the molding cavity (1); the flow field enclosure (13) is in the shape of a square tube and its axis is perpendicular to the bottom wall of the molding cavity (1); the buffer tubes and air inlet ends of the air outlet pieces of the upper air balancing pipe (3) and the lower air balancing pipe (2) are both connected to the internal space of the flow field enclosure (13).

8. The flow field device for purifying a printing chamber according to claim 1, characterized in that: The air outlet component comprises a lower air outlet pipe (6) which is connected to the molding cavity (1); the opening edge of the lower air outlet pipe (6) is rectangular in outline and its long side is parallel to the bottom wall of the molding cavity (1); the ventilation paths of the lower air outlet pipe (6) and the lower air equalizing pipe (2) are located in the same horizontal direction.

9. A flow field device for purifying a printing chamber according to claim 8, characterized in that: The air outlet member further comprises a flow stabilizer (8) connected to the lower air outlet pipe (6); the interior of the flow stabilizer (8) is a hollow structure; the flow stabilizer (8) is in a triangular or trapezoidal structure in a plane parallel to the air outlet surface; the lower air outlet pipe (6) is connected to the molding cavity (1) and the lower part of the flow stabilizer (8); an air outlet (81) is provided at the upper part of the flow stabilizer (8); and the air outlet (81) is located on the center line of the lower air outlet pipe (6).

10. A 3D printer, characterized in that: The invention comprises a flow field device for purifying a printing chamber as described in any one of claims 1 to 9.

Images