Laser coaxial fuse wire additive manufacturing equipment and method for simulating microgravity environment

Abstract

The invention discloses a laser coaxial fuse wire additive material device and method for simulating a microgravity environment, and the device comprises a laser coaxial fuse wire additive material device body, and a laser coaxial fuse wire feeding nozzle part is provided with a negative pressure suction method device. A plurality of liquid nitrogen circulation pipes are arranged on the outer side of the top of the negative pressure suction method device and externally connected with a cooling substance through the liquid nitrogen circulation pipes, airflow pipes are installed on the two sides of the negative pressure suction method device, a cooling shell is fixedly connected to the top of the negative pressure suction method device through the airflow pipes, and an annular negative pressure suction field is built in the vertical direction according to the Bernoulli principle in the whole process; according to the device, the gravity is balanced in real time, the laser fuse wire additive material in the microgravity environment can be simulated continuously and truly for a long time at low cost, the liquid nitrogen cooling and air flow protection device is integrated, the influence of thermal expansion caused by high temperature generated by laser heating on air flow disturbance and negative pressure suction method device deformation can be counteracted, and the laser fuse wire additive material is obtained. And meanwhile, a side-blowing protective gas device can be replaced, and oxidation in the additive printing process is prevented.

Description

Technical Field

[0001] The present invention belongs to the field of laser coaxial fuse additive equipment, and in particular relates to a laser coaxial fuse additive equipment and method for simulating a microgravity environment. Background Art

[0002] Currently, the mainstream mature methods for simulating the microgravity environment of additive manufacturing or welding processes are mainly the drop tower method and the parabolic flight method. The device falls with the gravitational acceleration g, and mg is all used to provide the acceleration g to achieve gravity offset and achieve the effect of microgravity.

[0003] Drop tower method: The experimental chamber is freely dropped from a height (about 100-200 meters) in a vacuum environment to obtain a microgravity environment for about 3-5 seconds. Parabolic flight method: A modified aircraft is used to climb at a 45° elevation angle and then dive along a parabolic trajectory. During the dive phase, a microgravity environment is generated for about 20-30 seconds. The disadvantages of the drop tower method and parabolic flight method in simulating the microgravity environment for additive manufacturing and welding processes are as follows: 1. Single microgravity simulations are short and discontinuous: Parabolic flight (15-30 seconds per run) and drop tower (3-5 seconds per run) experiments are limited by physical mechanisms, forcing them to be segmented. This makes it impossible to cover continuous process cycles, such as multi-layer deposition in fused filament additive manufacturing. This results in the forced interruption of key thermodynamic processes. For example, residual heat from the melt pool from the previous experiment disappears upon restart. Thermal accumulation effects cause nonlinear distortion due to intermittent interruptions, making it impossible to verify process parameters (such as the dynamic matching of wire feed speed and laser power) under real continuous conditions. Ultimately, ground-based experiments cannot accurately replicate the true thermodynamic boundary conditions of continuous manufacturing in space.

[0004] 2. High experimental cost and long time: The drop tower method and parabolic flight method are expensive to manufacture and the experimental cost is high. There are restrictions on the size and weight of the test equipment. The preparation, debugging and processing time of a single experiment are long. In order to piece together complete data, multiple short-term experiments need to be repeated. Intermittent interruptions increase energy consumption and time costs. Summary of the Invention

[0005] The purpose of the present invention is to provide a laser coaxial fuse additive device and method that simulates a microgravity environment to solve the problems mentioned in the above background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solutions: a laser coaxial fuse additive device for simulating a microgravity environment, comprising a laser coaxial fuse additive device body, a negative pressure suction device installed on the laser coaxial fuse wire feed nozzle, a plurality of liquid nitrogen flow tubes disposed on the outside of the top of the negative pressure suction device, and a cooling material connected to the liquid nitrogen flow tubes, airflow tubes installed on both sides of the negative pressure suction device, and a cooling housing fixedly connected to the top of the negative pressure suction device through the airflow tubes, and the cooling housing communicates with the interior of the negative pressure suction device through the airflow tubes; A fan is provided inside the airflow tube and a high-speed airflow is generated by the fan. The inner wall of the negative pressure suction method device opposite the fan is processed with a curved cross-sectional structure and the curved cross-sectional structure enables the center of the fan to generate an enhanced uniform annular rising airflow due to the pressure difference, thereby balancing the gravity of the molten droplets dripping from the welding wire.

[0007] Preferably, the liquid nitrogen flow pipes are provided in four and arranged in a circular array outside the negative pressure suction method device. The external cooling material is specifically cooled nitrogen and is filled into the negative pressure suction method device through the liquid nitrogen flow pipe to achieve the purpose of cooling. The cooled nitrogen acts as a protective gas by utilizing the properties of the cooled nitrogen.

[0008] Preferably, a cooling nitrogen gas outlet is provided at the bottom of the negative pressure suction method device near the inner side, and the outlet is arranged obliquely upward to form a high-speed airflow to generate a negative pressure area.

[0009] Preferably, the negative pressure suction method device further includes an arc-shaped partition inside, which divides the negative pressure suction method device into two areas. A plurality of pressure nozzles are provided on the arc-shaped partition, and the number of the pressure nozzles matches the number and position of the airflow tubes.

[0010] Preferably, a plurality of airflow regulating components are provided on the outer side of the arc-shaped partition plate, and the plurality of airflow regulating components are respectively provided between a plurality of pressure nozzles and the airflow pipes.

[0011] Preferably, the airflow adjustment assembly includes a guide plate 1 and a guide plate 2 that are movably connected to each other, and the guide plate 1 and the guide plate 2 are movably connected between a rotating shaft and the inner wall of the arc-shaped partition. A spring is provided on the outer side of the rotating shaft and the two ends of the spring are respectively connected to the guide plate 1 and the guide plate 2.

[0012] A method for using a laser coaxial fused wire additive device in a simulated microgravity environment, comprising the following steps: S1. Startup and calibration of negative pressure suction method microgravity simulation: Start the negative pressure suction method device (6) and the internal fan (4), open the external liquid nitrogen flow to fill the liquid nitrogen flow tube (3), generate an initial negative pressure field, and determine the air flow parameters for balancing gravity according to the characteristics of the materials used; S2. Preparation of laser coaxial fuse additive equipment and in-situ detection equipment: debug the coaxial fuse, high-speed camera and infrared thermal imager equipment, fix the substrate, and determine the relevant parameters; S3. Additive Manufacturing and Droplet Transfer in Microgravity: A laser beam is focused on a substrate to form a molten pool. A metal wire is fed into the center of the molten pool to achieve droplet transfer and spreading in a microgravity environment simulated by a negative pressure suction field. S4. Multi-physics field in-situ monitoring: A high-speed camera system captures the droplet detachment, spreading, and solidification processes in real time; an infrared thermal imager monitors the temperature distribution of the molten pool; S5. Additive manufacturing in microgravity environment is completed: After the target structure is formed layer by layer, the laser and wire feeding system are turned off, and the negative pressure suction field is maintained until the molten pool is completely solidified.

[0013] The technical effects and advantages of the present invention are as follows: 1. The entire process, based on the Bernoulli principle, creates an annular negative pressure suction field in the vertical direction, balancing gravity in real time. This allows for long-term, continuous, low-cost, and realistic simulation of laser-fused additive manufacturing in a microgravity environment. The present invention integrates a liquid nitrogen cooling and protective airflow device to offset the effects of thermal expansion caused by the high temperature generated by laser heating on airflow disturbances and deformation of the negative pressure suction method device. It can also replace the side-blowing protective gas device to prevent oxidation during the additive printing process, significantly reducing the cost of experimental verification of additive manufacturing in a microgravity environment. 2. When the corresponding air flow tube is inflated through the air flow regulating component, it will bend under force. When one of the air flow tubes is cut off, the guide plate 1 and the guide plate 2 in the air flow regulating component will be reset by the spring rebound force, so that the guide plate 1 and the guide plate 2 on the air flow regulating components on both sides that have not been cut off will still press against the inner wall of the arc-shaped partition to guide the air flow to the inner side of the guide plate 2 and the guide plate 1 that have been reset, that is, directly fill it into the pressure nozzle corresponding to the cut-off air flow tube to supplement the pressure, so that multiple pressure nozzles will not produce uneven pressure when one air flow tube is cut off. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the laser coaxial fuse device based on the negative pressure suction method of the present invention; Figure 2 Schematic diagram of the negative pressure suction method device of the present invention; Figure 3 This is a schematic cross-sectional view of the fan portion of the negative pressure suction method device of the present invention; Figure 4 This is a schematic cross-sectional view of the liquid nitrogen gas flow cooling channel of the present invention; Figure 5 It is a right cross-section and principle diagram of the negative pressure suction method device of the present invention; Figure 6 A three-dimensional diagram of the negative pressure suction method device of the present invention; Figure 7 Schematic diagram of the internal structure of the negative pressure suction method device of the present invention; Figure 8 This is a schematic structural diagram of the airflow adjustment assembly of the present invention; Figure 9 For the present invention Figure 8 A partial enlarged view of part A in the middle.

[0015] In the figure: 1. Cooling shell; 2. Air flow pipe; 3. Liquid nitrogen flow pipe; 4. Fan; 5. Curved cross-section structure; 6. Negative pressure suction method device; 601. Arc partition; 602. Pressure nozzle; 603. Air flow adjustment component; 6031. Guide plate 1; 6032. Guide plate 2; 6033. Spring; 6034. Rotating shaft. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] The present invention provides Figures 1-9 A laser coaxial fuse additive device for simulating a microgravity environment is shown in the figure, comprising a laser coaxial fuse additive device body, a laser coaxial fuse wire feeding nozzle equipped with a negative pressure suction method device 6, a plurality of liquid nitrogen flow tubes 3 are provided on the outside of the top of the negative pressure suction method device 6, and a cooling material is externally connected through the liquid nitrogen flow tubes 3, air flow tubes 2 are installed on both sides of the negative pressure suction method device 6, and a cooling shell 1 is fixedly connected to the top of the negative pressure suction method device 6 through the air flow tubes 2, and the cooling shell 1 is connected to the inside of the negative pressure suction method device 6 through the air flow tubes 2; A fan 4 is provided inside the airflow tube 2 and a high-speed airflow is generated by the fan 4. The inner wall of the negative pressure suction method device 6 opposite the fan 4 is processed with a curved cross-sectional structure 5, and the curved cross-sectional structure 5 enables the center of the fan 4 to generate an enhanced uniform annular rising airflow due to the pressure difference, thereby balancing the gravity of the molten droplets dripping from the welding wire.

[0018] Specifically, four liquid nitrogen flow pipes 3 are arranged in a circular array outside the negative pressure suction method device 6. The external cooling material is specifically cooled nitrogen and is filled into the negative pressure suction method device 6 through the liquid nitrogen flow pipes 3 to achieve the purpose of cooling. The cooled nitrogen acts as a protective gas by utilizing the properties of the cooled nitrogen.

[0019] Specifically, a cooling nitrogen gas outlet is provided at the bottom near the inner side of the negative pressure suction device 6 and the outlet is arranged obliquely upward to form a high-speed airflow to generate a negative pressure area.

[0020] Specifically, the negative pressure suction method device 6 also includes an arc-shaped partition 601 inside, which divides the negative pressure suction method device 6 into two areas. A plurality of pressure nozzles 602 are provided on the arc-shaped partition 601, and the number of the pressure nozzles 602 matches the number and position of the airflow tubes 2.

[0021] Specifically, a plurality of airflow regulating components 603 are provided outside the arc-shaped partition plate 601 , and the plurality of airflow regulating components 603 are respectively provided between the plurality of pressure nozzles 602 and the airflow pipe 2 .

[0022] Specifically, the airflow adjustment component 603 includes a guide plate 1 6031 and a guide plate 2 6032 that are movably connected to each other. The guide plate 1 6031 and the guide plate 2 6032 are movably connected to the inner wall of the arc-shaped partition 601 through a rotating shaft 6034. A spring 6033 is provided on the outside of the rotating shaft 6034 and the two ends of the spring 6033 are respectively connected to the guide plate 1 6031 and the guide plate 2 6032.

[0023] Example 1: Start the negative pressure suction device, turn on the liquid nitrogen flow, generate an initial negative pressure field, determine the gas flow parameters that can just balance the gravity according to the characteristics of the material used, debug the coaxial fuse, high-speed camera and infrared thermal imager and other equipment (the equipment here is directly installed in the existing technology and is available in laser coaxial fuse additive equipment, so it is not explained in detail), fix the substrate, determine the relevant parameters, focus the laser beam on the substrate to form a molten pool, and the metal wire is sent into the center of the molten pool to achieve molten droplet transfer and spreading in the microgravity environment simulated by the negative pressure suction field; after each single cladding is completed, the motion platform moves according to the preset path, and the laser head adjusts its position synchronously to carry out the next step or layer of additive manufacturing, and the high-speed camera system (the high-speed camera system here is specifically a high-speed camera, which is directly installed in the existing technology, so it is not described in detail) captures the molten pool in real time Droplet detachment, spreading and solidification process; infrared thermal imager monitors the temperature field distribution of the molten pool. After the target structure is formed layer by layer, the laser and wire feeding system are turned off, and the negative pressure suction field is retained until the molten pool is completely solidified. The differences in droplet detachment frequency, spreading radius and solidification morphology under microgravity and conventional gravity are compared and analyzed, and the forming quality and performance are analyzed. The entire process is based on Bernoulli's principle, creating an annular negative pressure suction field in the vertical direction to balance gravity in real time. It can simulate laser fuse additive in a microgravity environment for a long time, continuously, at low cost and realistically. The present invention integrates liquid nitrogen cooling and protective airflow devices, which can offset the effects of thermal expansion caused by the high temperature generated by laser heating on airflow disturbances and deformation of the negative pressure suction method device. At the same time, it can replace the side-blowing protective gas device to prevent oxidation during the additive printing process, greatly reducing the cost of additive experimental verification in a microgravity environment; Embodiment 2: Based on embodiment 1, an arc-shaped partition 601 is provided. This design is applied to special circumstances. When one of the air flow tubes 2 fans or channels leaks, in order to form a relatively balanced negative pressure area around the molten droplet by the negative pressure suction method device 6 as a whole, the present invention designs an arc-shaped partition 601. The arc-shaped partition 601 is used to isolate the air flow tube 2 from the liquid nitrogen cooling air flow outlet at the bottom of the negative pressure suction method device 6, so that the air flow is pre-charged on one side of the arc-shaped partition 601. When the pressure is met, the pressure nozzle 602 will automatically spray gas. At this time, the multiple pressure nozzles 602 spray out the air flow at equal pressure. When a problem occurs in one of the air flow tubes 2 and the flow is interrupted, the air flow regulating component 603 can be used. The setting is that the airflow regulating component 603 will be bent by force when the corresponding airflow tube 2 is inflated. When one of the airflow tubes 2 is cut off, the guide plate 1 6031 and the guide plate 2 6032 in the airflow regulating component 603 will be reset by the rebound force of the spring 6033, so that the guide plate 1 6031 and the guide plate 2 6032 on the airflow regulating components 603 on both sides that have not been cut off will still press against the inner wall of the arc-shaped partition 601 to guide the airflow to the inner side of the guide plate 2 6032 and the guide plate 1 6031 that have been reset, that is, directly fill it into the pressure nozzle 602 corresponding to the airflow tube 2 that is cut off, for pressure replenishment, so that multiple pressure nozzles 602 will not produce uneven pressure when one airflow tube 2 is cut off.

[0024] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A laser coaxial fused wire additive device for simulating a microgravity environment, comprising a laser coaxial fused wire additive device body, characterized in that: A negative pressure suction device is installed on the laser coaxial fuse wire feeding nozzle. Several liquid nitrogen flow tubes are provided on the outside of the top of the negative pressure suction device, and a cooling material is connected to the outside through the liquid nitrogen flow tubes. Airflow tubes are installed on both sides of the negative pressure suction device, and a cooling shell is fixedly connected to the top of the negative pressure suction device through the airflow tubes. The cooling shell is connected to the inside of the negative pressure suction device through the airflow tubes. A fan is provided inside the airflow tube and a high-speed airflow is generated by the fan. The inner wall of the negative pressure suction method device opposite the fan is processed with a curved cross-sectional structure and the curved cross-sectional structure enables the center of the fan to generate an enhanced uniform annular rising airflow due to the pressure difference, thereby balancing the gravity of the molten droplets dripping from the welding wire.

2. The laser coaxial fused wire additive device for simulating a microgravity environment according to claim 1, characterized in that: The liquid nitrogen flow pipes are provided with four and are arranged in a circular array outside the negative pressure suction method device. The external cooling material is specifically cooled nitrogen and is filled into the negative pressure suction method device through the liquid nitrogen flow pipe to achieve the purpose of cooling. The cooled nitrogen is used as a protective gas by utilizing the properties of the cooled nitrogen.

3. The laser coaxial fused wire additive device for simulating a microgravity environment according to claim 2, characterized in that: A cooling nitrogen gas outlet is provided near the inner side of the bottom of the negative pressure suction method device, and the outlet is arranged obliquely upward to form a high-speed airflow to generate a negative pressure area.

4. The laser coaxial fused wire additive device for simulating a microgravity environment according to claim 3, characterized in that: The negative pressure suction method device further includes an arc-shaped partition inside, which divides the negative pressure suction method device into two areas. A plurality of pressure nozzles are provided on the arc-shaped partition, and the number of the pressure nozzles matches the number and position of the airflow tubes.

5. The laser coaxial fused wire additive device for simulating a microgravity environment according to claim 4, characterized in that: A plurality of airflow regulating components are arranged on the outer side of the arc-shaped partition plate, and the plurality of airflow regulating components are respectively arranged between the plurality of pressure nozzles and the airflow pipes.

6. The laser coaxial fused wire additive device for simulating a microgravity environment according to claim 5, characterized in that: The airflow adjustment assembly includes a guide plate 1 and a guide plate 2 that are movably connected to each other. The guide plate 1 and the guide plate 2 are movably connected to each other through a rotating shaft and the inner wall of the arc-shaped partition. A spring is provided on the outer side of the rotating shaft and the two ends of the spring are respectively connected to the guide plate 1 and the guide plate 2.

7. The method for using the laser coaxial fused wire additive device for simulating a microgravity environment according to claim 6, characterized in that: The specific steps are as follows: S1. Start and calibrate the negative pressure suction microgravity simulation: Start the negative pressure suction device and its internal blower, and start the external liquid nitrogen flow to fill the liquid nitrogen flow tube to generate an initial negative pressure field. Based on the material properties used, determine the airflow parameters to balance gravity. S2. Preparation of laser coaxial fuse additive equipment and in-situ detection equipment: debug the coaxial fuse, high-speed camera and infrared thermal imager equipment, fix the substrate, and determine the relevant parameters; S3. Additive Manufacturing and Droplet Transfer in Microgravity: A laser beam is focused on a substrate to form a molten pool. A metal wire is fed into the center of the molten pool to achieve droplet transfer and spreading in a microgravity environment simulated by a negative pressure suction field. S4. Multi-physics field in-situ monitoring: A high-speed camera system captures the droplet detachment, spreading, and solidification processes in real time; an infrared thermal imager monitors the temperature distribution of the molten pool; S5. Additive manufacturing in microgravity environment is completed: After the target structure is formed layer by layer, the laser and wire feeding system are turned off, and the negative pressure suction field is maintained until the molten pool is completely solidified.

Images