Liquid metal droplet transition control device and method in space microgravity environment

Abstract

The invention discloses a device and a method for controlling a metal droplet transition process under a space environment condition. The device comprises a monitoring camera, a braking device, a welding wire, a driving wheel and a laser transmitter. In the space environment condition fuse wire manufacturing process, a welding wire is continuously fed into a molten pool under the action of a driving wheel, the end of the welding wire is molten to form molten drops under the action of a heat source, and the molten drops make contact with the molten pool and enter the molten pool in a transition mode under the action of surface tension. A monitoring camera is used for obtaining a molten drop image in real time, the maximum diameter d of a molten drop and the distance L between the molten drop and a molten pool are calculated based on an image vision algorithm, and when it is detected that the d value exceeds a set threshold value dmax or L is larger than 0, the molten drop transition process is correspondingly regulated and controlled; the molten welding wire can enter the molten pool in a transition mode under the space environment condition, and the forming quality of a component is guaranteed.

Description

Technical Field

[0001] The present invention relates to a device and method for controlling the transition of liquid metal droplets in a space microgravity environment, belonging to the technical field of manufacturing metal materials in a space environment. Background Art

[0002] Affected by factors such as meteorite particle and space debris impacts, long-term in-orbit spacecraft face serious damage risks, posing a serious threat to the development of extraterrestrial space resource exploration projects such as Mars and lunar exploration. There is an urgent need to study in-orbit maintenance and repair technologies for spacecraft.

[0003] The processing and manufacturing of metal structures are essential technologies to meet in-orbit maintenance of spacecraft and ensure the smooth implementation of various extraterrestrial space resource exploration plans. The fuse manufacturing process is involved in the processing and manufacturing of metal structures, that is, the wire melts under the action of a heat source to form droplets and then transitions into the molten pool.

[0004] Under ground conditions, various behaviors of molten metal are affected by both gravity and surface tension, but the influence of gravity is more significant and dominates the process. Under the conditions of a space microgravity environment, surface tension will gradually dominate the dynamic behavior of the molten pool, causing significant changes in droplet transition, molten pool flow, heat and mass transfer characteristics, etc. during the fuse manufacturing process. In a space environment, when the droplet separates from the molten pool during the fuse manufacturing process, the droplet cannot transition into the molten pool under the action of surface tension and gravity, resulting in a reduction in the forming quality of the component and even interruption of the manufacturing process. Summary of the Invention

[0005] The technical problem solved by the present invention is: overcoming the deficiencies of the prior art, providing a device and method for controlling the transition of liquid metal droplets in a space microgravity environment to ensure that the melted welding wire can transition into the molten pool under space environmental conditions and ensure the forming quality of the component.

[0006] The technical solution of the present invention is: A device for controlling the transition process of metal droplets in a space environment includes: a monitoring camera, a braking device, a welding wire, a driving wheel, and a laser emitter;

[0007] The monitoring camera is fixed on the side of the welding wire through a fixture and is used to collect the droplet image at the end of the welding wire during the processing;

[0008] There are two driving wheels on the left and right of the welding wire, both of which are in direct contact with the welding wire. When the driving wheels rotate, they drive the welding wire to continuously feed towards the substrate;

[0009] The braking device is connected to the rotating shaft of the driving wheel. By reducing the distance between the rotating shafts of the driving wheels, the driving wheel is controlled to clamp the welding wire, so that when the welding wire stops, an acceleration in the direction of the molten pool is provided for the droplet;

[0010] The laser emitter is fixed to the side of the welding wire by a fixture and is used to emit a laser beam to bombard the end of the molten droplet, prompting the molten droplet to separate from the end of the welding wire and transition into the molten pool.

[0011] The laser emitter is configured with a rotating shaft and can change the laser emission direction according to the position of the end of the molten droplet to ensure that the laser beam can bombard the end of the molten droplet.

[0012] The driving wheel has a diameter of 25 mm, can adapt to welding wires with diameters of 0.8 mm, 1.0 mm, and 1.2 mm, and can regulate the wire feeding speed in the range of 0 - 3000 mm / min.

[0013] The laser emitter can adjust the laser power between 0 - 1500 W; the rotating shaft configured on the laser emitter can change the included angle within the range of 0° - 180°, thereby adjusting the direction of the laser beam so that the laser beam can bombard the position of the end of the molten droplet.

[0014] The maximum resolution of the monitoring camera is 1280*1024, and the maximum frame rate is 50 FPS under the condition of the maximum resolution.

[0015] The braking device can adjust the distance between the axles of the two driving wheels within the range of 25 - 28 mm.

[0016] A method for controlling the transition of liquid metal droplets in a space microgravity environment using the above device includes:

[0017] Performing wire melting processing under space microgravity environment conditions; during the processing, during the welding process, the driving wheel controls the continuous feeding of the welding wire to the substrate. The end of the welding wire melts to form a molten droplet under the action of the heat source. The molten droplet contacts the molten pool and transitions into the molten pool under the action of surface tension to achieve the forming of the component; meanwhile, a monitoring camera is used to obtain the image of the molten droplet at the end of the welding wire in real time, calculate the maximum diameter d of the molten droplet and the distance L between the molten droplet and the molten pool based on the digital image processing algorithm, and regulate the molten droplet transition process according to the values of d and L to ensure that the molten droplet formed by the melting of the welding wire during the manufacturing process can always transition into the molten pool in the form of a liquid bridge.

[0018] The regulation of the molten droplet transition process according to the values of d and L includes:

[0019] When L is equal to 0, that is, the molten droplet contacts the molten pool, and the value of d is less than the set threshold d max At this time, the molten droplet transition process is stable, and it is not necessary to regulate various process parameters;

[0020] When L is greater than 0, that is, the molten droplet is separated from the molten pool, or L is equal to 0 and the value of d exceeds the set threshold d maxWhen controlling the droplet transfer process, specifically: first stop the rotation of the driving wheels, then control the braking device to act, clamp the welding wire by reducing the distance between the two driving wheels, stop the movement of the welding wire, provide an acceleration for the droplet towards the molten pool direction, then control the laser emitter to emit a laser beam to bombard the end of the welding wire, prompt the droplet to separate from the welding wire and contact the molten pool, and form a liquid bridge between the welding wire and the molten pool to ensure the stability of the metal droplet transfer process under space environmental conditions.

[0021] Both the welding wire and the substrate are 5A06 aluminum alloy, the diameter of the welding wire is 1.2 mm, and the wire feeding speed is 1200 mm / min; the initial value of the included angle of the laser emitter is 60°, the laser power is 1000 W, and the initial value of the distance m between the axes of the two driving wheels is 26 mm.

[0022] The set threshold d of the droplet diameter max = 3.0 mm.

[0023] The advantages of the present invention compared with the prior art are as follows:

[0024] 1. Using a monitoring camera to obtain the manufacturing process image and calculate the maximum diameter of the droplet and the distance between the droplet and the molten pool as the basis for controlling the droplet transfer process, which has the advantages of non-contact, high measurement accuracy, wide measurement range, etc.

[0025] 2. By adopting the method of reducing the distance between the driving wheels of the welding wire to clamp and stop the welding wire, providing an acceleration for the droplet towards the molten pool direction, which has the advantages of simple device structure, small volume, small weight, low energy consumption, etc.

[0026] 3. Adopting the method of bombarding the end of the droplet with a laser beam to promote the contact between the large-size droplet and the molten pool, ensuring the stability of the wire manufacturing process, which has the advantages of fast equipment response and regulation speed. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the wire manufacturing process under space environmental conditions;

[0028] Figure 2 It is a schematic diagram of the regulation of the wire manufacturing process under space environmental conditions. Detailed Embodiment

[0029] The present invention relates to a device for controlling the metal droplet transfer process under space environmental conditions, including: a monitoring camera, a braking device, a welding wire, a driving wheel, and a laser emitter;

[0030] The monitoring camera is fixed on the side of the welding wire through a fixture and is used to collect the droplet image at the end of the welding wire during the processing;

[0031] There are two driving wheels on the left and right of the welding wire, both of which are in direct contact with the welding wire. When the driving wheels rotate, they drive the welding wire to continuously feed into the substrate.

[0032] The braking device is connected to the rotating shaft of the driving wheel. By reducing the distance between the rotating shafts of the driving wheels, the braking device controls the driving wheels to clamp the welding wire, so that when the welding wire stops, an acceleration in the direction of the molten pool is provided for the molten droplet.

[0033] The laser emitter is fixed to the side of the welding wire by a fixture and is used to emit a laser beam to bombard the end of the molten droplet, prompting the molten droplet to separate from the end of the welding wire and transition into the molten pool.

[0034] The laser emitter is configured with a rotating shaft and can change the laser emission direction according to the position of the end of the molten droplet to ensure that the laser beam can bombard the end of the molten droplet.

[0035] The driving wheels have a diameter of 25 mm, can adapt to welding wires with diameters of 0.8 mm, 1.0 mm, and 1.2 mm, and can regulate the wire feeding speed in the range of 0 - 3000 mm / min.

[0036] The laser emitter can adjust the laser power between 0 - 1500 W; the rotating shaft configured on the laser emitter can change the included angle within the range of 0° - 180°, thereby adjusting the direction of the laser beam so that the laser beam can bombard the position of the end of the molten droplet.

[0037] The maximum resolution of the monitoring camera is 1280*1024, and the maximum frame rate is 50 FPS under the condition of the maximum resolution.

[0038] The braking device can adjust the distance between the axles of the two driving wheels within the range of 25 - 28 mm.

[0039] The present invention also relates to a method for controlling the transition of liquid metal droplets in a space microgravity environment by using the above device, including:

[0040] Conducting wire melting processing under the conditions of a space microgravity environment; during the processing, during the welding process, the driving wheels control the welding wire to continuously feed into the substrate. The end of the welding wire melts to form a molten droplet under the action of a heat source. The molten droplet contacts the molten pool and transitions into the molten pool under the action of surface tension to realize the forming of the component; meanwhile, a monitoring camera is used to continuously acquire images of the molten droplet at the end of the welding wire, calculate the maximum diameter d of the molten droplet and the distance L between the molten droplet and the molten pool based on a digital image processing algorithm, and regulate the molten droplet transition process according to the values of d and L to ensure that the molten droplets formed by the melting of the welding wire during the manufacturing process can always transition into the molten pool in the form of a liquid bridge.

[0041] The regulation of the molten droplet transition process according to the values of d and L includes:

[0042] When L equals 0, that is, the molten droplet contacts the molten pool, and the value of d is less than the set threshold d max the molten droplet transfer process is stable, and it is not necessary to adjust various process parameters;

[0043] When L is greater than 0, that is, the molten droplet separates from the molten pool, or L equals 0 and the value of d exceeds the set threshold d max the molten droplet transfer process is adjusted as follows: First, stop the rotation of the driving wheels, then control the action of the braking device, clamp the welding wire by reducing the distance between the two driving wheels, stop the movement of the welding wire, provide an acceleration in the direction of the molten pool for the molten droplet, then control the laser emitter to emit a laser beam to bombard the end of the welding wire, prompt the molten droplet to separate from the welding wire and contact the molten pool, and form a liquid bridge between the welding wire and the molten pool to ensure the stability of the metal molten droplet transfer process under space environmental conditions.

[0044] Both the welding wire and the substrate are 5A06 aluminum alloy, the diameter of the welding wire is 1.2 mm, and the wire feeding speed is 1200 mm / min; the initial value of the included angle of the laser emitter is 60°, the laser power is 1000 W, and the initial value of the distance m between the axes of the two driving wheels is 26 mm.

[0045] The set threshold d of the molten droplet diameter max = 3.0 mm.

[0046] As Figure 1 、 2 shown, a device and method for controlling the transfer process of liquid metal molten droplets in a space microgravity environment provided by the present invention are described by taking the aluminum alloy welding process as a specific embodiment:

[0047] 1) The welding wire grade is 5A06, the diameter is 1.2 mm, and the wire feeding speed is 1200 mm / min; the substrate grade is 5A06, and the size is 200*150*10 mm.

[0048] 2) Set the set threshold d of the molten droplet diameter max = 3.0 mm; the initial value of the included angle of the laser emitter is 60°, the laser power is 1000 W; the initial value of the distance m between the axes of the two driving wheels is 26 mm.

[0049] 3) During the welding process, the driving wheels control the continuous feeding of the welding wire to the substrate. The end of the welding wire melts to form a molten droplet under the action of the heat source. The molten droplet contacts the molten pool and transfers into the molten pool under the action of surface tension to realize the forming of the component.

[0050] 4) During the welding process, a monitoring camera is used to obtain the molten droplet image, and the maximum diameter d of the molten droplet and the distance L between the molten droplet and the molten pool are calculated in real time based on the digital image processing algorithm.

[0051] 5) When the value of d exceeds the set threshold dmax When L is greater than 0 (the droplet separates from the molten pool), the braking device is controlled to clamp the welding wire to stop the wire feeding. Under the action of inertia, the droplet moves towards the molten pool. Subsequently, a laser beam is emitted to bombard the end of the droplet, prompting the droplet to separate from the wire end and contact the molten pool. Under the action of surface tension, the droplet is transferred into the molten pool, realizing the regulation of the metal droplet transfer process in the space environment.

[0052] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the disclosed technical content without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A metal droplet transfer process control device under space environment conditions, characterized in that: include: Monitoring camera, brake device, welding wire, drive wheel, laser transmitter; The monitoring camera is fixed to the side of the welding wire by a clamp and is used to collect the molten droplet image at the end of the welding wire during the processing; There are two driving wheels on the left and right of the welding wire, both of which are in direct contact with the welding wire. When the driving wheels rotate, they drive the welding wire to be continuously fed to the substrate; The braking device is connected to the rotating shaft of the driving wheel, and controls the driving wheel to clamp the welding wire by reducing the distance between the rotating shafts of the driving wheels, so that the welding wire stops and the molten droplet is accelerated in the direction of the molten pool; The laser emitter is fixed to the side of the welding wire by a clamp, and is used to emit a laser beam to bombard the end of the molten droplet, so as to cause the molten droplet to separate from the end of the welding wire and transition into the molten pool.

2. The device according to claim 1, characterized in that The laser emitter is equipped with a rotating shaft, which can change the laser emission direction according to the position of the end of the molten droplet, so as to ensure that the laser beam can bombard the end of the molten droplet.

3. The device according to claim 1, characterized in that The driving wheel has a diameter of 25 mm, can adapt to welding wires with diameters of 0.8 mm, 1.0 mm, and 1.2 mm, and can adjust the wire feeding speed within the range of 0-3000 mm / min.

4. The device according to claim 1, characterized in that The laser emitter can adjust the laser power between 0-1500W; the rotating shaft configured for the laser emitter can change the angle within the range of 0°-180°, thereby adjusting the direction of the laser beam so that the laser beam can bombard the end position of the molten droplet.

5. The device according to claim 1, characterized in that The maximum resolution of the monitoring camera is 1280*1024, and the maximum frame rate is 50FPS under the maximum resolution condition.

6. The device according to claim 1, characterized in that The brake device can adjust the distance between the two drive wheel axles within the range of 25-28 mm.

7. A method for controlling the transfer of liquid metal droplets in a space microgravity environment using the device of claim 1, characterized in that: include: Conduct fuse processing and manufacturing in space microgravity environment; During the manufacturing process, the driving wheel controls the welding wire to be continuously fed to the substrate. The end of the welding wire melts under the action of the heat source to form a molten droplet. The molten droplet contacts the molten pool and transitions into the molten pool under the action of surface tension to realize the forming of the component. At the same time, a monitoring camera is used to obtain the image of the molten droplet at the end of the welding wire in real time. The maximum diameter d of the molten droplet and the distance L between the molten droplet and the molten pool are calculated based on the digital image processing algorithm. The molten droplet transition process is regulated according to the values ​​of d and L to ensure that the molten droplets formed by the melting of the welding wire during the manufacturing process can always transition into the molten pool in the form of a liquid bridge.

8. The method according to claim 7, characterized in that The method of regulating the droplet transfer process according to the values ​​of d and L includes: When L is equal to 0, the droplet is in contact with the molten pool, and the d value is less than the set threshold d max When the droplet transfer process is stable, there is no need to adjust the process parameters; When L is greater than 0, the droplet is separated from the molten pool, or L is equal to 0 and the d value exceeds the set threshold d max The molten droplet transfer process is regulated by first stopping the rotation of the driving wheel, and then controlling the action of the braking device to clamp the welding wire by reducing the distance between the two driving wheels, so that the welding wire stops moving and provides acceleration for the molten droplet toward the molten pool. Then, the laser emitter is controlled to emit a laser beam to bombard the end of the welding wire, so that the molten droplet separates from the welding wire and contacts with the molten pool, forming a liquid bridge between the welding wire and the molten pool, thereby ensuring the stability of the metal molten droplet transfer process under space environment conditions.

9. The method according to claim 8, characterized in that The welding wire and substrate are both 5A06 aluminum alloy, the welding wire diameter is 1.2 mm, and the wire feeding speed is 1200 mm / min; the initial value of the laser emitter angle is 60°, the laser power is 1000 W, and the initial value of the distance m between the two driving wheel shafts is 26 mm.

10. The method according to claim 8, characterized in that Setting threshold d for droplet diameter max =3.0mm.

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