A wind field structure for an SLM device, an SLM device

Abstract

This invention provides a blowing structure for an SLM (Self-Drying Molding) device and the SLM device itself. The SLM device includes a forming chamber. The blowing structure includes an upper air inlet and a lower air inlet disposed on the same side wall of the forming chamber, with the upper air inlet located above the lower air inlet. Air outlet pipes are installed on opposite side walls of the forming chamber where the upper and lower air inlets are located. Both the upper and lower air inlets include a gas diffusion section, a mixing section, and a rectification section along the gas flow direction. The inlet of the gas diffusion section is connected to a gas source. Along the gas flow direction, the width of the gas diffusion section gradually increases and its height gradually decreases. The mixing section is used to mix and homogenize the airflow from the gas diffusion section, and the rectification section is used to homogenize and directionally rectify the airflow from the mixing section. The blowing structure of this invention can precisely control the outflow state of the protective gas, fundamentally optimizing the airflow distribution above the forming area.

Description

Technical Field

[0001] This invention belongs to the field of wind farm technology for SLM equipment, and particularly relates to a wind farm structure for SLM equipment and SLM equipment. Background Technology

[0002] Selective Laser Melting (SLM) is a metal 3D printing process. Software slices the part to be printed into layers, and a high-energy-density laser scans the metal powder according to the geometry of each layer, causing the powder to melt rapidly and then solidify again to form metal layers. The final part is produced through the accumulation of these metal layers. Because it can directly manufacture high-performance, complex-structured metal parts, it has achieved large-scale application in high-end manufacturing fields such as aerospace precision components and personalized medical implants. However, with the increasing size of the formed parts (i.e., large-format SLM equipment is becoming a trend) and the growing demand for long-term continuous printing, the large amounts of metal vapor, fumes, and molten spatter generated when the high-energy laser acts on the metal powder pose a serious challenge to the stability of the forming process and the quality of the final part. The uniformity of the protective gas flow field within the forming cavity is a core control element that directly determines process stability and part quality. Non-uniform flow field, i.e., significant differences in airflow velocity, direction, or stability at different locations on the working area (powder bed plane), will trigger a series of chain reactions, ultimately leading to serious forming defects and production problems. The specific hazards are mainly manifested as follows: In the low-speed zone, the airflow cannot effectively guide and exhaust smoke and metal vapor, causing them to stagnate and leading to laser energy attenuation, molten pool contamination and local protection failure; In the high-speed zone, the excessive airflow physically impacts the molten pool and powder bed, directly causing molten pool instability, increased splashing, powder erosion and uneven cooling, thereby systematically destroying the stability and consistency of the forming process.

[0003] Ultimately, the aforementioned problems are all directly related to the inability of traditional air intake structural designs to generate and maintain a laminar or quasi-laminar flow wind field that covers a large working area, has a highly uniform velocity field, and possesses strong directional transport capabilities. Therefore, to solve the various forming defects caused by insufficient wind speed uniformity, ensure the quality consistency and process stability of parts produced by large-format SLM equipment, and reduce maintenance costs, an innovative air intake structural design is urgently needed. Summary of the Invention

[0004] In view of this, the present invention provides a wind field structure for SLM equipment and an SLM equipment. The blowing structure of the present invention can precisely control the outflow state of the protective gas, fundamentally optimizing the wind field distribution above the forming area.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: The first aspect of the present invention provides a wind field structure for an SLM device, the SLM device including a forming chamber, the blowing structure including an upper air inlet, a lower air inlet and an air outlet pipe disposed on the same side wall of the forming chamber, the upper air inlet being located above the lower air inlet, and the air outlet pipe being installed on the side wall of the forming chamber opposite to the side wall where the upper air inlet and the lower air inlet are installed; Both the upper and lower air intakes include a gas diffusion section, a mixing section, and a rectification section along the gas flow direction. The inlet of the gas diffusion section is connected to the gas source. Along the gas flow direction, the width of the gas diffusion section gradually increases and the height gradually decreases. The mixing section is used to mix and homogenize the airflow from the gas diffusion section, and the rectification section is used to homogenize and directionally rectify the airflow from the mixing section.

[0006] In a preferred embodiment of the first aspect of the present invention, a plurality of guide vanes are provided inside the gas diffusion section to form a plurality of air intake ducts.

[0007] In a preferred embodiment of the first aspect of the present invention, the guide plate is adapted to the structure of the gas diffusion section in terms of height and length.

[0008] In a preferred embodiment of the first aspect of the present invention, the gas diffusion section and the rectification section are arranged horizontally, the mixing section is an inclined air duct, and the gas diffusion section and the rectification section are respectively at an angle to the mixing section.

[0009] In a preferred embodiment of the first aspect of the present invention, multiple layers of grid plates are arranged at intervals along the gas flow direction for uniform directional airflow. The grating plate has a preset thickness and has multiple channels.

[0010] In a preferred embodiment of the first aspect of the present invention, a first grid plate and a second grid plate are arranged at intervals along the gas flow direction within the rectifying section.

[0011] In a preferred embodiment of the first aspect of the present invention, the cross-sectional area of ​​the pores of the first grid plate is smaller than the cross-sectional area of ​​the pores of the second grid plate.

[0012] In a preferred embodiment of the first aspect of the present invention, the cross-sectional shape of the holes on the first and second grid plates is a regular shape such as a circle, rhombus, square, rectangle or regular hexagon.

[0013] In a preferred embodiment of the first aspect of the present invention, the upper edge of the upper air inlet is aligned with the inner surface of the top wall of the molding chamber, the lower edge of the lower air inlet is 10 mm above the printing plane of the molding chamber, and the height of the air outlet of the lower air inlet is not less than 50 mm.

[0014] In a preferred embodiment of the first aspect of the present invention, the width of the air outlets of the upper and lower air inlets is at least 100 mm larger than the maximum printing width of the SLM device.

[0015] A second aspect of the present invention provides an SLM device, including the blowing structure for an SLM device according to all embodiments of the first aspect.

[0016] Because the present invention adopts the above technical solution, it has the following advantages and positive effects compared with the prior art: The airflow structure provided by this invention includes an upper air inlet and a lower air inlet installed on the same side wall of the SLM forming chamber. The upper air inlet is installed above the laser scanning working area and its function is to generate a uniform and clean downward protective air curtain to isolate the smoke and splashes generated by the printing plane below and protect the optical system above. The lower air inlet is installed on the side wall of the powder bed area and its function is to construct a uniform and stable main process airflow covering the powder bed for immediate removal of smoke and dust, guidance of splashes, and stabilization of the molten pool flow field. Both the upper and lower air inlets include a diffusion section, a mixing section, and a rectifying section along the gas flow direction. Along the gas flow direction, the width of the diffusion section gradually increases and its height gradually decreases. The mixing section mixes and homogenizes the airflow from the diffusion section. The rectifying section is a constant cross-section air duct responsible for the final velocity homogenization and directional rectification of the airflow. Therefore, this invention achieves uniform coverage of the protective airflow and three-dimensional graded treatment of pollutants through the synergistic effect of upper and lower dual air intakes with diffusion, mixing and rectification functions. It fundamentally overcomes the problems of uneven air field, local protection failure and incomplete pollutant removal in traditional single-side or top air intake schemes. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the wind field structure in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the lower air intake of the wind field structure in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the diffusion section of the wind field structure in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the mixing section of the wind field structure in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the rectification section of the wind farm structure in Embodiment 1 of the present invention.

[0018] Figure descriptions: 1-Forming chamber; 2-Lower air inlet; 21-Diffuser section; 211-Guide plate; 22-Mixing section; 23-Rectifying section; 231-First grid plate; 232-Second grid plate; 3-Outlet pipe; 4-Air source; 5-Upper air inlet; 6-Channel. Detailed Implementation

[0019] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a wind farm structure for SLM equipment and the SLM equipment proposed in this invention. The advantages and features of this invention will become clearer from the following description.

[0020] Example 1 like Figure 1 As shown, this embodiment provides an airflow structure for an SLM (Surface Mount Technology) device. The SLM device includes a forming chamber 1. The airflow structure includes an upper air inlet 5, a lower air inlet 2, and an exhaust pipe 3, all disposed on the same side wall of the forming chamber 1. The upper air inlet 5 is located above the lower air inlet 2. The exhaust pipe 3 is installed on the opposite side walls of the forming chamber 1 where the upper air inlet 5 and lower air inlet 2 are installed. The exhaust port of the upper air inlet 5 is located above the laser scanning working area, and its function is to generate a uniform and clean downward protective air curtain to isolate the smoke and splashes generated by the printing plane below, protecting the optical system above. The exhaust port of the lower air inlet 2 is located on the side wall of the powder bed plane (usually located on both sides of the scraper running direction), and its function is to construct a uniform and stable main process airflow on the powder bed surface to instantly remove smoke and dust, guide splashes, and stabilize the melt pool flow field. The upper air inlet 5 and lower air inlet 2 can be connected to the same filtered air source 4 (e.g., Figure 1 (As shown), it can also be controlled independently.

[0021] like Figure 2 As shown, both the upper air intake duct 5 and the lower air intake duct 2 include a gas diffusion section 21, a mixing section 22, and a rectifying section 23 along the gas flow direction. Taking the lower air intake duct as an example, the structure of the air intake duct is explained in detail. The inlet of the gas diffusion section 21 is connected to the gas source. Along the gas flow direction, the width of the gas diffusion section 21 gradually increases and its height gradually decreases. The gradually increasing width of the gas diffusion section 21 matches the outlet width of the gas diffusion section 21 with the required printing area. The gradually decreasing height of the gas diffusion section 21 serves to concentrate the airflow and accelerate its flow within the gas diffusion section 21. The mixing section 22 connects to the outlet of the diffusion section 21. The mixing section 22 is configured to exchange momentum and mix the airflow from the diffusion section 21 to initially homogenize the velocity distribution. The rectifying section 23 connects after the mixing section 22. The rectifying section 23 is a constant cross-section air duct, which performs final velocity homogenization and directional rectification of the airflow.

[0022] In one embodiment, multiple guide vanes 211 can be provided inside the gas diffusion section 21, forming multiple air intake ducts inside the gas diffusion section 21. For example... Figure 3 As shown, the guide vane 211 is adapted to the structure of the gas diffusion section 21 in terms of height and length. Specifically, in terms of length, the guide vane 211 gradually expands outward from the inlet to the outlet of the gas diffusion section 21, so as to... Figure 3For example, there are 7 guide vanes 211 in the gas diffusion section 21. The central guide vane 211 is centrally located, while the guide vanes 211 on both sides gradually expand outward. With such a structure and layout, the channel in the gas diffusion section 21 can be divided into multiple air ducts, which can effectively guide the airflow and make each air duct evenly distributed to make the airflow in each air duct balanced, avoid separation and eddies, and ensure that the airflow is evenly diffused to the entire outlet.

[0023] In one embodiment, the mixing section 22 connects the diffuser section 21 and the rectifying section 23, and the mixing section 22 is located after the diffuser section 21 in the airflow direction, such as... Figure 1 and 2 As shown, the diffuser section 21 and the rectifier section 23 are horizontally arranged, and the mixing section 22 forms an angle with the diffuser section 21 and the rectifier section 23 respectively, as shown. Figure 4 As shown, the mixing section 22 is an inclined air duct with a constant cross-section, which can be inclined upwards or downwards, as... Figure 1 As shown, the mixing section 22 in the upper air intake duct 5 is inclined upwards along the airflow direction, while the mixing section 22 in the lower air intake duct 2 is inclined downwards along the airflow direction. The airflow, whose velocity distribution is still uneven after being expanded by the diffuser section 21, enters this inclined flow channel, where its streamlines are forcibly altered and intersected, resulting in redistribution. This design utilizes the flow field disturbance generated by the ramp structure to force the airflow from different micro-channels to undergo intense momentum exchange and mixing, thereby rapidly homogenizing the large-area dispersed airflow after diffusion, laying the foundation for the subsequent rectification section 23.

[0024] In another embodiment, the rectifying section 23 is connected after the mixing section 22 in the airflow direction. Its main function is to perform final fine-tuning of the velocity field and straightening of the airflow after it has been thoroughly mixed and basically homogenized. Specifically, as follows... Figure 2 and Figure 5 As shown, multiple layers of grid plates are arranged at intervals within the rectifier section 23 along the gas flow direction. The grid plates have a preset thickness and multiple channels 6. Gas can only flow through the channels 6 to the intervals or outlets of the grid plates, thereby forcing the airflow along the channels 6, thus directional airflow and dispersing vortices.

[0025] The cross-sectional shape of the holes 6 on the grating plate can be a regular shape or an irregular shape. The regular shape can be a circle, rhombus, square, rectangle or regular hexagon, etc.

[0026] Preferably, along the gas flow direction, the first grid plate and the second grid plate 232 are arranged at intervals within the rectifying section 23. Too many grid plates will increase resistance and pressure; therefore, it is preferable to use... Figure 4 The first and second grid plates 232 are arranged at the intervals shown.

[0027] Furthermore, the cross-sectional area of ​​the channel 6 in the first grid plate is smaller than that in the second grid plate 232. If the cross-sectional shape of the channel 6 is circular, then the aperture of the channel 6 in the first grid plate is smaller than that in the second grid plate 232. Located in the direction of gas flow, the cross-sectional area of ​​the channel 6 in the upstream first grid plate is smaller, primarily serving to initially equalize and stabilize the gas flow. The cross-sectional area of ​​the channel 6 in the downstream second grid plate 232 is larger, enabling it to perform final sorting and orientation of the airflow, forcing the airflow along the axis of the channel 6 (i.e., the designed outlet direction), thereby outputting an air curtain with consistent direction and uniform velocity. A predetermined distance is maintained between the first and second grid plates 232 to provide stable space for airflow adjustment.

[0028] To optimize the airflow effect, the upper edge of the upper air inlet 5 is aligned with the inner surface of the top wall of the molding chamber 1, the lower edge of the lower air inlet 2 is 10 mm above the printing plane (substrate plane) of the molding chamber 1, and the height of the air outlet of the lower air inlet 2 is not less than 50 mm. Simulated airflow effects show that the above installation method effectively optimizes the airflow.

[0029] Furthermore, the width of the air outlets of the upper air intake duct 5 and the lower air intake duct 2 is at least 100mm wider than the maximum print width of the SLM device to ensure complete coverage and eliminate edge effects. Here, the maximum print width of the SLM device refers to the maximum length and width that the SLM device supports for printing.

[0030] Example 2 This embodiment provides an SLM device, including the wind farm structure for the SLM device of Embodiment 1.

[0031] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A wind farm structure for an SLM (Sequencing Power Management) device, the SLM device comprising a molding chamber, characterized in that, The blowing structure includes an upper air inlet and a lower air inlet disposed on the same side wall of the molding chamber. The upper air inlet is located above the lower air inlet. An air outlet pipe is installed on the side wall opposite to the side wall where the upper air inlet and the lower air inlet are installed in the molding chamber. Both the upper and lower air intakes include a gas diffusion section, a mixing section, and a rectification section along the gas flow direction. The inlet of the gas diffusion section is connected to the gas source. Along the gas flow direction, the width of the gas diffusion section gradually increases and the height gradually decreases. The mixing section is used to mix and homogenize the airflow from the gas diffusion section, and the rectification section is used to homogenize and directionally rectify the airflow from the mixing section.

2. The wind farm structure for SLM equipment according to claim 1, characterized in that, The gas diffusion section is equipped with multiple guide vanes to form multiple air intake ducts.

3. The wind farm structure for SLM equipment according to claim 2, characterized in that, The guide plate is adapted to the structure of the gas diffusion section in terms of height and length.

4. The wind farm structure for SLM equipment according to claim 1, characterized in that, The gas diffusion section and the rectification section are horizontally arranged, and the mixing section is an inclined air duct. The gas diffusion section and the rectification section are at an angle to the mixing section.

5. The wind farm structure for SLM equipment according to claim 1, characterized in that, Along the gas flow direction, multiple layers of grid plates are arranged at intervals within the rectifying section to uniformly directional airflow. The grating plate has a preset thickness and has multiple channels.

6. The wind farm structure for SLM equipment according to claim 4, characterized in that, Along the gas flow direction, the first grid plate and the second grid plate are arranged at intervals within the rectifying section.

7. The wind farm structure for SLM equipment according to claim 5, characterized in that, The cross-sectional area of ​​the pores in the first grid plate is smaller than that in the second grid plate.

8. The wind farm structure for SLM equipment according to claim 1, characterized in that, The upper edge of the upper air inlet is aligned with the inner surface of the top wall of the molding chamber, the lower edge of the lower air inlet is 10 mm above the printing plane of the molding chamber, and the height of the air outlet of the lower air inlet is not less than 50 mm.

9. The wind farm structure for SLM equipment according to claim 1, characterized in that, The width of the air outlets of the upper and lower air inlets is at least 100 mm larger than the maximum printing width of the SLM device.

10. An SLM device, characterized in that, The wind farm structure for SLM equipment as described in any one of claims 1-9.

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