Laser high-fidelity cross-domain transmission system for laser welding

Abstract

The invention discloses a laser high-fidelity cross-domain transmission system for laser welding, and belongs to the technical field of laser welding. The invention aims to solve the problem of loss when laser beams are transmitted from an atmospheric environment to a vacuum environment. Comprising an input optical fiber used for being connected with an optical fiber interface of a laser and transmitting a laser beam; the optical coupling structure is used for performing collimation and focusing adjustment on the laser beam transmitted by the input optical fiber to obtain a target laser beam; the cross-domain transmission optical fiber interface is arranged on the closed cabin and used for transmitting the target laser beam into the closed cabin and irradiating the target laser beam to the surface of the workpiece to be welded; the sealing device is used for sealing the joint of the closed cabin and the cross-domain transmission optical fiber interface; the input end and the output end of the optical coupling structure are provided with cooling devices. The device is used for transmitting laser from the atmospheric environment to the vacuum environment.

Description

Technical Field

[0001] The invention relates to a laser high-fidelity cross-domain transmission system for laser welding, and belongs to the technical field of laser welding. Background Art

[0002] Vacuum laser welding is a welding technology that uses a high-energy laser beam as a heat source to connect materials in a vacuum environment. Under vacuum conditions, the laser welding plume is suppressed, increasing the material's energy absorption rate. The increase in evaporation recoil pressure caused by changes in the material's physical properties significantly increases the laser's penetration depth, making the processing capabilities and weld quality of vacuum laser welding close to those of electron beam welding. With the development of vacuum laser welding technology, due to its significant advantages such as no magnetic bias, no radiation hazards, low vacuum requirements, high processing flexibility, and good system integration, it has become a preferred alternative to electron beam welding. Its application in aerospace component manufacturing is becoming increasingly widespread, and it has become one of the key welding and repair technologies for in-orbit space manufacturing.

[0003] However, whether vacuum laser welding is implemented on the ground or lasers are applied in space environments, lasers usually need to operate in an atmospheric environment. This requires that the laser beam must be generated from the atmospheric environment and efficiently transmitted to the vacuum environment. In this cross-domain transmission process, a series of core challenges need to be urgently addressed: high-reliability sealing under conditions of large pressure difference between the atmosphere and vacuum, suppression of beam quality loss at the interface, and management of thermal effects caused by high-power laser transmission. Therefore, the development of a comprehensive solution that can achieve lossless and high-fidelity transmission of high-power lasers under large pressure difference between the atmosphere and vacuum, and collaboratively solve the efficient entry of water, electricity, gas and other media required for laser welding into the cabin, has become an urgent need for the development of vacuum laser and space on-orbit laser welding technology.

[0004] There are two main methods for implementing vacuum laser welding: placing the welding head externally within a sealed vacuum chamber and placing the welding head internally within the chamber. In existing vacuum laser welding and wire filling methods with an external welding head, a laser transmission window is set above the sealed chamber. The laser is emitted through the welding head outside the chamber and enters the vacuum chamber through the window. A two-stage vacuum chamber is used to enhance the protection of the window. This layout improves the utilization of the vacuum space and avoids the problem of frequent replacement of laser lenses. However, the external method limits the flexibility of laser processing, restricting the position and structure of the workpiece that can be processed. In existing vacuum laser welding methods with an internal welding head, the laser is introduced into the vacuum chamber via optical fiber and vacuum laser welding is achieved through the laser welding head inside the chamber. This method can achieve welding of complex paths or components through an internal motion mechanism, improving processing flexibility. However, since optical fiber is directly used to introduce the laser into the chamber, the overall sealing of the chamber is affected by the optical fiber. The vacuum glue sealing has problems such as poor sealing and impaired beam quality, which limits the overall sealing and energy transmission effects. In addition, existing technologies have also proposed an insertable laser inlet device that can achieve air cooling and protection of vacuum laser welding lenses. This device uses inert gas to cool the incident lens to prevent the lens from being affected by heat and reducing the beam quality. However, when using gas for cooling, a large flow rate can easily lead to an increase in the vacuum level inside the cabin, thereby affecting the welding quality. Considering the vacuum level and beam quality requirements of vacuum laser and space-orbit welding technology, further development requires solving the problems of atmosphere-vacuum cross-domain transmission sealing and beam quality loss. At the same time, considering the problems of thermal management in the actual welding process, it is also necessary to overcome the difficulties of auxiliary water, electricity, and gas coordinated entry into the cabin. However, there are no related reports in the field of laser atmosphere-vacuum high-fidelity cross-domain transmission.

[0005] In summary, developing a method that can achieve high-fidelity cross-domain transmission of laser beams for welding is of great significance for improving vacuum laser welding processing capabilities and promoting the development and application of vacuum laser welding technology and on-orbit laser welding in space. Summary of the Invention

[0006] In response to the loss problem of laser beam transmitted from atmospheric environment to vacuum environment, the present invention provides a laser high-fidelity cross-domain transmission system for laser welding.

[0007] A laser high-fidelity cross-domain transmission system for laser welding of the present invention comprises:

[0008] Input optical fiber, used to connect to the optical fiber interface of the laser to transmit the laser beam;

[0009] The optical coupling structure is used to collimate and focus the laser beam transmitted by the input optical fiber to obtain the target laser beam;

[0010] A cross-domain transmission optical fiber interface is provided on the closed cabin, and is used to transmit the target laser beam from outside the closed cabin to inside the closed cabin or from inside the closed cabin to outside the closed cabin, and irradiate the surface of the workpiece to be welded; the closed cabin is in a vacuum environment or an atmospheric environment, and the corresponding closed cabin is in an atmospheric environment or a vacuum environment;

[0011] Sealing device, used to achieve sealing of the connection between the closed cabin and the cross-domain transmission optical fiber interface;

[0012] The input end and the output end of the optical coupling structure are configured with cooling devices.

[0013] According to the present invention, the laser high-fidelity cross-domain transmission system for laser welding also includes an XY position adjustment device and a mirror group adjustment device. The XY position adjustment device is used to adjust the XY direction position of the input optical fiber, and the mirror group adjustment device is used to adjust the position of the optical coupling structure. The target laser beam is obtained through the coordinated adjustment of the XY position adjustment device and the mirror group adjustment device.

[0014] According to the laser high-fidelity cross-domain transmission system for laser welding of the present invention, the optical coupling structure includes a light-emitting optical fiber, a collimating lens group, a beam combiner, a focusing lens group and a light outlet. The light-emitting optical fiber is connected to the input optical fiber. The output laser beam of the light-emitting optical fiber is collimated by the collimating lens group and then incident on the beam combiner. The reflected laser beam of the beam combiner is focused by the focusing lens group, and then the target laser beam is obtained through the light outlet and transmitted to the cross-domain transmission optical fiber interface.

[0015] The optical outlet is connected to the cross-domain transmission optical fiber interface.

[0016] According to the laser high-fidelity cross-domain transmission system for laser welding of the present invention, an end cap is fused to the end face of the light-emitting optical fiber.

[0017] According to the laser high-fidelity cross-domain transmission system for laser welding of the present invention, the lenses in the collimating lens group and the focusing lens group are both coated with a high-energy laser film.

[0018] According to the laser high-fidelity cross-domain transmission system for laser welding of the present invention, the single-sided residual reflection of the high-energy laser film is less than 1%, and the corresponding lens can withstand a power of 15W / cm 2 above.

[0019] According to the laser high-fidelity cross-domain transmission system for laser welding of the present invention, the sealing device includes a water jacket sealing device and a window sealing device, and the sealing device is equipped with a reserved water and electrical interface.

[0020] According to the laser high-fidelity cross-domain transmission system for laser welding of the present invention, the cooling device adopts a water-cooling circulation system.

[0021] According to the laser high-fidelity cross-domain transmission system for laser welding of the present invention, a temperature sensor is configured for the optical coupling structure, and a water pressure sensor is configured for the cooling device;

[0022] The temperature sensor is used to sense the online temperature of the optical coupling, and the water pressure sensor is used to sense the water pressure in the cooling device;

[0023] The state of the cooling device is adjusted according to the online temperature and the water pressure in the cooling device.

[0024] According to the laser high-fidelity cross-domain transmission system for laser welding of the present invention, the input optical fiber adopts a QBH / QD interface, and the cross-domain transmission optical fiber interface adopts a laser welding head-optical fiber-QBH / QD interface; the optical fiber diameters of the input optical fiber and the cross-domain transmission optical fiber interface are both 100~400μm.

[0025] Beneficial effects of the present invention: The system of the present invention is used to achieve high-fidelity cross-domain transmission of lasers for laser welding, and is suitable for achieving high-fidelity cross-domain transmission of high-power laser energy in vacuum and atmospheric environments in metal material welding, and is particularly suitable for application scenarios of vacuum laser welding and on-orbit laser welding in space. In order to address the problems of interface sealing, energy dissipation, beam quality suppression, and thermal effects caused by the cross-domain transmission process of high-power lasers in different gas environments, the present invention uses optical path elements to transmit laser beams, achieving high-fidelity cross-domain transmission of high-power lasers in an atmospheric-vacuum environment, solving the problem of coordinated water / electricity / gas entry into the cabin, and providing core support for vacuum welding of complex aerospace components and on-orbit manufacturing of space stations.

[0026] The system of the present invention has made a breakthrough in the high-fidelity transmission technology of high-power laser across domains (atmosphere-vacuum), and has realized stable, lossless and high-quality transmission of high-power laser between the atmosphere and vacuum environments.

[0027] The system of the present invention realizes lossless and high-fidelity transmission of high-power lasers across large pressure difference conditions in vacuum-atmosphere environments through an optical coupling structure with a lens optical path system. The system of the present invention can be used for vacuum laser welding and space on-orbit laser welding, and has a wide range of process applicability, and can be applied to the welding process of various metal materials such as steel, aluminum alloys, magnesium alloys, and titanium alloys. Through the setting of the optical coupling structure, not only the beam quality during cross-domain transmission of the laser is guaranteed, but also the sealing and thermal management problems of closed containers in the atmosphere-vacuum environment are solved. The present invention provides important equipment support for the further application and integration of vacuum laser welding technology in complex components, and provides a solution to the cross-domain transmission of space lasers faced by future space on-orbit laser welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1Schematic diagram of the structure of the laser high-fidelity cross-domain transmission system for laser welding according to the present invention;

[0029] Figure 2 It is a structural schematic diagram of the optical coupling structure. DETAILED DESCRIPTION

[0030] 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 any creative efforts shall fall within the scope of protection of the present invention.

[0031] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0033] Specific implementation method 1. Combination Figure 1 and Figure 2 As shown, the present invention provides a laser high-fidelity cross-domain transmission system for laser welding, comprising:

[0034] Input fiber 1, used to connect to the optical fiber interface of the laser to transmit the laser beam;

[0035] The optical coupling structure 5 is used to collimate and focus the laser beam transmitted by the input optical fiber 1 to obtain a target laser beam;

[0036] The cross-domain transmission optical fiber interface 8 is provided on the closed cabin 7 and is used to transmit the target laser beam from outside the closed cabin to inside the closed cabin or from inside the closed cabin to outside the closed cabin, and irradiate the surface of the workpiece to be welded; the closed cabin is in a vacuum environment or an atmospheric environment, and the corresponding closed cabin is in an atmospheric environment or a vacuum environment;

[0037] Sealing device 6, used to achieve sealing at the connection between the closed compartment 7 and the cross-domain transmission optical fiber interface 8;

[0038] The input and output ends of the optical coupling structure 5 are configured with cooling devices 2 .

[0039] In this embodiment, in order to ensure the stable operation of the optical coupling structure 5 in a vacuum / atmospheric environment, a cooling device 2 and a sealing device 6 are provided.

[0040] The optical coupling structure 5 can couple and transmit the laser beam in the atmospheric environment to the vacuum environment for laser processing and ensure coupling efficiency. It can also realize laser beam coupling transmission in a space environment by placing the laser in a closed cabin by exchanging the input and output ends.

[0041] Combine Figure 1 As shown, this embodiment further includes an XY position adjustment device 3 and a mirror group adjustment device 4. The XY position adjustment device 3 is used to adjust the XY direction position of the input optical fiber 1, and the mirror group adjustment device 4 is used to adjust the position of the optical coupling structure 5. The target laser beam is obtained by the coordinated adjustment of the XY position adjustment device 3 and the mirror group adjustment device 4.

[0042] The XY position adjustment device 3 and the lens group adjustment device 4 serve as a focus adjustment system, ensuring the smooth transmission of laser energy.

[0043] The lens group adjustment device 4 can adjust the position of each lens group individually and perform comprehensive joint adjustment.

[0044] As an example, combined with Figure 2 As shown, the optical coupling structure 5 includes a light-emitting fiber 51, a collimating lens group 53, a beam combining lens 54, a focusing lens group 55 and a light outlet 56. The light-emitting fiber 51 is connected to the input fiber 1. The outgoing laser beam of the light-emitting fiber 51 is collimated by the collimating lens group 53 and then incident on the beam combining lens 54. The reflected laser beam of the beam combining lens 54 is focused by the focusing lens group 55, and then obtained through the light outlet 56 to transmit the target laser beam to the cross-domain transmission fiber interface 8; the cross-domain transmission fiber interface 8 can realize the transmission of the laser beam to the outside or inside of the closed cabin when the laser is placed inside or outside the closed cabin;

[0045] The light outlet 56 is connected to the cross-domain transmission optical fiber interface 8 .

[0046] An end cap 52 is fused to the end face of the light-emitting optical fiber 51 to reduce power density and protect the light beam system.

[0047] The lenses in the collimating lens group 53 and the focusing lens group 55 are coated with a high-energy laser film to protect the lenses.

[0048] In this embodiment, as a preference, the single-side residual reflection of the high-energy laser film is less than 1%, and the corresponding lens can withstand a power of 15W / cm 2 above.

[0049] As an example, the sealing device 6 includes a water jacket sealing device and a window sealing device. The sealing device 6 is equipped with a reserved water and electricity interface and adopts a dry air source as a safety guarantee.

[0050] In this embodiment, the cooling device 2 adopts a water cooling circulation system.

[0051] A temperature sensor is configured for the optical coupling structure 5, and a water pressure sensor is configured for the cooling device 2;

[0052] The temperature sensor is used to sense the online temperature of the optical coupling, and the water pressure sensor is used to sense the water pressure in the cooling device 2;

[0053] The PC monitoring interface 9 can be used to monitor and adjust the status of the cooling device 2 according to the online temperature and the water pressure in the cooling device 2, and to issue a safety alarm.

[0054] As an example, the input optical fiber 1 adopts a QBH / QD interface, and the cross-domain transmission optical fiber interface 8 adopts a laser welding head-optical fiber-QBH / QD interface; the optical fiber diameters of the input optical fiber 1 and the cross-domain transmission optical fiber interface 8 are both 100~400μm, and the optical fiber diameters are both downward compatible.

[0055] Preferably, the input optical fiber 1 may have a core diameter of 300 μm, which makes coupling and alignment less difficult than when the core diameter is 200 μm.

[0056] The specific use method of the present invention includes:

[0057] S1: Turn on the cooling device 2, ensure that the sealing device is in good condition, and clamp and fix the workpiece to be welded in the closed chamber 7;

[0058] In step S1: The cooling device uses water cooling to cool the external and internal optical devices. The whole device is equipped with a water cooling circulation system, and the water cooler is standard with real-time feedback of water temperature. The sealing device uses water jacket seals and window seals to separate the internal and external atmospheres, and adds sealing rings to each level of pipelines to achieve coordinated entry of water, electricity and gas into the cabin and ensure sealing. The atmosphere inside and outside the closed cabin is different. In the application scenario of vacuum laser welding, the interior is a vacuum environment and the exterior is an atmospheric environment. The laser is placed outside the cabin, and the laser welding head and the workpiece to be welded are placed inside the cabin; in the application scenario of on-orbit laser welding in space, the interior is an atmospheric environment and the exterior is a space environment. The laser is placed inside the cabin, and the welding head and the workpiece to be welded are placed outside the cabin.

[0059] S2: The optical fiber interface output from the laser is input into the optical coupling structure 5 through the input optical fiber 1 from the atmospheric environment;

[0060] In step S2, the input fiber uses a QBH / QD interface with a diameter of 100-400μm and backward compatibility to reduce coupling and focusing difficulties and improve coupling efficiency. The optical coupling structure 5 has an end cap 52 fused to the end face of the output fiber 51 to reduce power density and protect the beam system. The lenses in the collimating lens assembly 53 and focusing lens assembly 55 are coated with a high-energy laser coating for protection.

[0061] S3: Use the laser teaching light to pass through the XY position adjustment device 3 to ensure the spatial position accuracy of the input laser and determine the focal position and focal length of the laser through the lens group adjustment device 4;

[0062] In step S3, the XY position adjustment device 3 and the lens group adjustment device 4 in the focus adjustment system can adjust the position of each lens group individually and in combination, thereby achieving changes in the spatial position of the optical path and precisely controlling the laser light path and focus position. If the fiber core diameter is relatively small, such as 100-200μm, more precise adjustment of the adjustment mechanism is required to ensure the accuracy of the system light source position.

[0063] S4: Monitoring the working status of the optical coupling structure 5 through the PC monitoring interface 9;

[0064] In step S4, the system's temperature, water flow, and water pressure sensors are all monitored in real time by the PC interface 9, with safety alarms issued when monitoring parameters exceed thresholds. Furthermore, the QBH output head has two metal slip rings. When inserted into the QBH collimator, they contact the collimator's internal contacts, forming a closed loop and providing feedback via the PC monitoring interface 9.

[0065] S5: Turn on the laser, and the high-power laser beam is transmitted from the atmospheric environment through the optical coupling structure 5 and output to the closed chamber 7 by the cross-domain transmission optical fiber interface 8, and irradiated to the vacuum environment inside the chamber, focusing on the surface of the workpiece to be welded for processing.

[0066] In step S5: the laser beam quality should be BPP < 5 mm mrad, including conventional low-power lasers and high-energy lasers (such as continuous laser power up to kW or even MW level, pulsed laser energy up to J or even kJ level, power density up to MW / cm 2 The laser type used is determined by the welding characteristics of the workpiece and the available power interface for the application. High-energy lasers are often used for vacuum laser welding of medium and thick plates, while lower-power lasers are often used for thin plate welding or in-orbit laser welding of spacecraft. The output uses a laser welding head-fiber-QBH / QD interface (100-400μm), with backward compatibility across all fiber diameters.

[0067] Example:

[0068] In order to facilitate understanding of the present invention, Figure 1 and Figure 2 , the vacuum laser welding process and IPG laser, IPG D50 Wobble oscillating laser head are used as examples to describe the present invention in more detail.

[0069] S1: Turn on the cooling device through the operation interface, set the water temperature to 25±1℃, the flow rate to 10L / min, and ensure that the sealing device is sealed. Clamp the workpiece to be welded in the designated position of the closed chamber 7.

[0070] S2: The IPG laser is placed in an atmospheric environment, and its 300μm output fiber QBH interface is inserted into the collimation structure of the input fiber 1. The light output port is connected to the cross-domain transmission fiber interface 8 through the QBH interface and connected to the IPG D50 Wobble swing laser head. When the connection is successful, the monitoring interface shows that the coupling transmission input and output fiber connection is completed.

[0071] S3: Start the laser's teaching laser (red light) and operate the XY position adjustment device 3 (accuracy ±0.01mm) to adjust the horizontal offset of the optical path so that the center of the light spot is located at the center of the lens; adjust the collimating lens group 53 and the focusing lens group 55 through the lens group adjustment device 4 (including the Z-axis focusing module) to set the focal length to the same as the standard focal length of the IPG D50 welding head, which is 247mm, and adjust the focus to focus on the workpiece surface.

[0072] S4: According to the display on PC monitoring interface 9, set the optical module temperature to less than 35°C, the water pressure to 0.5 MPa, and the QBH interface slip ring circuit closure signal to be normal, and confirm that the optical fiber connection is correct.

[0073] S5: Set the laser to 6000W output power and a beam quality (BPP) of 3.5mm·mrad. Evacuate chamber 7 to 0.1kPa. The chamber is now in a vacuum, while the laser is exposed to the atmosphere outside. The laser beam is transmitted from the atmosphere through an optical coupling structure and then transmitted through cross-domain transmission fiber interface 8 to the enclosed chamber 7, where it irradiates the workpiece surface for welding.

[0074] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be employed in conjunction with other described embodiments.

Claims

1. A laser high-fidelity cross-domain transmission system for laser welding, characterized in that: include: Input optical fiber, used to connect to the optical fiber interface of the laser to transmit the laser beam; The optical coupling structure is used to collimate and focus the laser beam transmitted by the input optical fiber to obtain the target laser beam; A cross-domain transmission optical fiber interface is provided on the closed cabin, and is used to transmit the target laser beam from outside the closed cabin to inside the closed cabin or from inside the closed cabin to outside the closed cabin, and irradiate the surface of the workpiece to be welded; the closed cabin is in a vacuum environment or an atmospheric environment, and the corresponding closed cabin is in an atmospheric environment or a vacuum environment; Sealing device, used to achieve sealing of the connection between the closed cabin and the cross-domain transmission optical fiber interface; The input end and the output end of the optical coupling structure are configured with cooling devices.

2. The laser high-fidelity cross-domain transmission system for laser welding according to claim 1, characterized in that: It also includes an XY position adjustment device and a mirror group adjustment device. The XY position adjustment device is used to adjust the XY direction position of the input optical fiber, and the mirror group adjustment device is used to adjust the position of the optical coupling structure. The target laser beam is obtained through the coordinated adjustment of the XY position adjustment device and the mirror group adjustment device.

3. The laser high-fidelity cross-domain transmission system for laser welding according to claim 2, characterized in that: The optical coupling structure includes a light-emitting fiber, a collimating lens group, a beam combiner, a focusing lens group and a light outlet. The light-emitting fiber is connected to the input fiber. The output laser beam of the light-emitting fiber is collimated by the collimating lens group and then incident on the beam combiner. The reflected laser beam of the beam combiner is focused by the focusing lens group and then obtained through the light outlet to obtain a target laser beam and transmitted to the cross-domain transmission fiber interface. The optical outlet is connected to the cross-domain transmission optical fiber interface.

4. The laser high-fidelity cross-domain transmission system for laser welding according to claim 3, characterized in that: An end cap is fused at the end face of the light-emitting optical fiber.

5. The laser high-fidelity cross-domain transmission system for laser welding according to claim 4, characterized in that: The lenses in the collimating lens group and the focusing lens group are coated with high-energy laser film.

6. The laser high-fidelity cross-domain transmission system for laser welding according to claim 5, characterized in that: The single-side residual reflection of the high-energy laser film is less than 1%, and the corresponding lens can withstand a power of 15W / cm 2 above.

7. The laser high-fidelity cross-domain transmission system for laser welding according to claim 1, characterized in that: The sealing device includes a water jacket sealing device and a window sealing device, and the sealing device is equipped with a reserved water, electricity and gas interface.

8. The laser high-fidelity cross-domain transmission system for laser welding according to claim 1, characterized in that: The cooling device adopts a water cooling circulation system.

9. The laser high-fidelity cross-domain transmission system for laser welding according to claim 8, characterized in that: A temperature sensor is configured for the optical coupling structure, and a water pressure sensor is configured for the cooling device; The temperature sensor is used to sense the online temperature of the optical coupling, and the water pressure sensor is used to sense the water pressure in the cooling device; The state of the cooling device is adjusted according to the online temperature and the water pressure in the cooling device.

10. The laser high-fidelity cross-domain transmission system for laser welding according to claim 1, characterized in that: The input optical fiber adopts a QBH / QD interface, and the cross-domain transmission optical fiber interface adopts a laser welding head-optical fiber-QBH / QD interface; the optical fiber diameters of the input optical fiber and the cross-domain transmission optical fiber interface are both 100~400μm.

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