Device and method for controlling laser wire welding droplets based on environmental pressure changes

Abstract

This invention discloses a device and method for controlling laser filler wire welding droplets based on changes in environmental pressure. In the device, a laser transmission window is located in a high-pressure cavity and aligned with the laser welding head to guide the laser beam. A quartz glass plate is vertically connected to the side opposite to the quartz glass to collect metal vapor nanoparticles generated during laser welding at different heights. A movable slider is slidably connected to a guide rail, and the sample is supported on the movable slider to move to the welding position. A wire feeding pulley group is located in the high-pressure cavity to deliver the welding wire to the welding position. A camera faces the observation window to capture image information of the welding process. A plasma spectrometer is aligned with the laser transmission window at a predetermined angle to collect spectral signals generated during the welding process. Based on the image information and spectral signals, the pressure in the high-pressure cavity is adjusted. The environmental pressure level during the welding process can be controlled at any time to regulate the droplet transition behavior and weld formation characteristics.

Description

Technical Field

[0001] The invention belongs to the field of welding technology, and in particular to a device and method for controlling a laser wire-filling welding droplet based on a change in environmental pressure. Background Art

[0002] Wire welding can not only reduce the requirements of workpiece processing for laser welding, but also improve the composition of the weld by using different welding wires. At the same time, it can effectively avoid solidification cracks caused by welding seam cooling. Therefore, it is increasingly widely used in new nuclear fuel rod welding, internal high-pressure gas packaging of devices in nuclear power and electronics industries, underwater welding and repair. For every 100 meters increase in water depth, the pressure increases by 1MPa. Therefore, it is necessary to study the relevant physical mechanism of laser wire welding in high-pressure environment and develop equipment.

[0003] The use of high-pressure chambers provides the required high-pressure environment for high-pressure welding. Traditional high-pressure environment welding tests use arc welding heat sources such as TIG welding and MIG welding, and install the welding head inside the chamber, which makes the chamber volume too large. Increasing the environmental pressure by means of a booster pump can easily cause gas residue inside the chamber, affecting the welding results and low operating efficiency. Laser wire welding uses an external laser heat source and built-in welding wire, which greatly reduces the chamber volume.

[0004] The biggest difference between laser wire welding and traditional laser autogenous welding is that welding wire is added as a supplementary material for weld formation. The quality of welding and the quality of weld formation are closely related to the state of welding wire when it is melted. Usually, there are three types of transition forms of molten droplets in laser wire welding, namely particle transition, mixed transition and liquid bridge transition. The welding results obtained by these three types of molten droplet transition forms are very different, so it is necessary to study the transition behavior of molten droplets in different pressure environments.

[0005] During the laser welding process, plasma and metal vapor will be generated above the area where the laser beam directly acts, collectively known as plasma plume. When the laser beam passes through the plasma plume, part of the energy will be absorbed by the plasma, and the laser beam will also be refracted and scattered, resulting in a decrease in laser energy density. The density of the gas in the space increases in a high-pressure environment, and more gas is ionized to produce plasma in a high-temperature environment. At the same time, changes in environmental pressure will also affect the melting and boiling points of the metal, affecting the metal evaporation process, thereby affecting the efficiency and quality of welding. Therefore, it is necessary to study the behavior of plasma plume under different environmental pressures.

[0006] The dynamic behavior of the molten pool during laser welding is an important research object that affects the welding quality. It directly determines the weld defects, weld structure, etc. The generation and change of plasma plume is an important factor driving the flow of the molten pool; at the same time, the transition of the molten droplet directly acts on the molten pool during laser wire welding, and its transition form will greatly affect the dynamic change process of the molten pool. Both can directly affect the flow, heat transfer and stability of the molten pool. Therefore, studying the changes in plasma plume and the transition form of molten droplets during laser wire welding has guiding significance for improving welding quality.

[0007] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0008] In view of the problems existing in the prior art, the present invention proposes a device and method for controlling the molten droplet in laser wire welding based on changes in ambient pressure, studies the correlation between the molten droplet transition behavior, molten pool behavior and molten pool dynamics behavior and ambient pressure under different ambient pressures, and designs the weld morphology by controlling the molten droplet transition behavior by controlling the ambient pressure.

[0009] The object of the present invention is achieved through the following technical scheme: a device for controlling laser wire welding droplets based on environmental pressure changes comprises:

[0010] a laser welding head that controllably emits a laser beam;

[0011] A high pressure chamber comprising:

[0012] An air inlet, which is provided at one end of the high-pressure cavity and can be connected to the argon gas cylinder in an on-off manner;

[0013] An air outlet, which is arranged at the other end of the high-pressure cavity away from the air inlet, and the air outlet and the air inlet regulate the high-pressure cavity to be at a pressure p;

[0014] an observation window, which is visually arranged on the high-pressure chamber;

[0015] A laser transmission window, which is disposed in the high-pressure cavity and aligned with the laser welding head to introduce the laser beam;

[0016] Quartz glass, located on a side of the laser projection window opposite to the laser welding head;

[0017] A quartz glass sheet, which is connected to the side of the quartz glass opposite to the quartz glass in a liftable manner to collect metal vapor nanoparticles generated during laser welding at different heights;

[0018] A linear movable slide, which is arranged in the high-pressure cavity, and the linear movable slide comprises a guide rail extending in the high-pressure cavity;

[0019] A movable slider, which is slidably connected to the guide rail, and the sample is supported on the movable slider to move to a welding position;

[0020] A wire feeding pulley assembly, which is arranged in the high-pressure chamber to transport the welding wire to the welding position;

[0021] A camera facing the observation window to capture image information of the welding process;

[0022] a plasma spectrometer, which is aligned with the laser transmission window at a predetermined angle to collect spectral signals generated during the welding process;

[0023] A processor is connected to the high-pressure chamber, the camera and the plasma spectrometer, and is used to adjust the pressure in the high-pressure chamber based on the image information and the spectral signal.

[0024] In the device for controlling laser wire welding droplets based on environmental pressure changes, the image information includes the size of plasma generated during welding, the melting state information of the welding wire and / or the number range of metal vapor nanoparticles.

[0025] In the device for controlling laser wire welding droplets based on changes in ambient pressure, the gas inlet is connected to an argon gas cylinder via a pressure reducing valve, and the pressure reducing valve is connected to the processor.

[0026] In the device for controlling laser wire welding droplets based on changes in ambient pressure, the gas outlet is provided with a back pressure valve, and the back pressure valve is connected to the processor.

[0027] In the device for controlling laser wire welding droplets based on changes in ambient pressure, the linear movable slide is adjustable in height.

[0028] In the device for controlling laser wire filling welding droplets based on changes in ambient pressure, the linear movable slide includes a motor that drives the movable slider, the motor is wirelessly connected to the slide remote control trigger module, the wire feeding pulley group is wirelessly connected to the wire feeding remote control trigger module, and the wire feeding remote control trigger module is respectively coupled with the laser welding head so that the sample, welding wire and laser beam are triggered simultaneously.

[0029] In the device for controlling laser wire welding droplets based on environmental pressure changes, the pressure p is 50Pa-2.0MPa, and the predetermined angle is 45 degrees.

[0030] In the device for controlling laser wire welding droplets based on environmental pressure changes, the processor adjusts the welding process so that the weld penetration H changes with the pressure P, H=6.5*P^(-0.264), and the droplet transition T period is T=36.4+0.24*P as the pressure P changes.

[0031] In the device for controlling laser wire welding droplets based on environmental pressure changes, a filter is arranged between the camera and the observation window, and the transmittance of quartz glass to 1070nm fiber laser is greater than or equal to 95%.

[0032] The control method of the device for controlling laser wire welding droplets based on environmental pressure changes comprises the following steps:

[0033] The sample is placed on a moving slide to move to a welding position with the movement and a wire feeding pulley group delivers welding wire to the welding position, and the welding position is directly below the quartz glass sheet;

[0034] The laser welding head emits a laser beam toward the welding position, the spot center of the laser beam coincides with the junction of the sample and the welding wire, half of the spot is on the sample, and the other half is on the welding wire;

[0035] The camera captures image information of the welding process, and the plasma spectrometer collects spectral signals generated during the welding process. The pressure in the high-pressure chamber is adjusted based on the image information and spectral signals, so that the laser wire welding droplets in the welding process can be controlled.

[0036] Compared with the prior art, the present invention has the following advantages: the outlet of the argon gas bottle of the present invention is connected to the high-pressure cavity after passing through the pressure reducing valve, the entry of the gas is controlled by the switch of the argon gas bottle, and the pressure level in the high-pressure cavity is controlled by adjusting its size, so that the pressure level inside the high-pressure cavity can be adjusted instantly and smoothly, the pressure adjustment range of the high-pressure cavity is 50Pa-2MPa, and it is steplessly adjusted during the adjustment process, the position of the laser welding head remains unchanged during the welding process, and continuous displacement is achieved by adjusting the linear moving slide inside the high-pressure cavity, and at the same time, the slide remote control trigger module and the wire feeding remote control trigger module are coupled and connected with the laser electric control cabinet to achieve the simultaneous movement, light emission and wire feeding of the trinity, in the actual operation process, the welding speed is controlled by adjusting the sliding speed of the moving slider, and the wire feeding speed is controlled by adjusting the parameters of the wire feeding remote control trigger module, and at the same time, the height of the quartz glass sheet can be adjusted to collect metal vapor nanoparticles generated during laser welding at different heights, and the nano metal particles inside and outside the beam path can be distinguished. In addition, the plasma size and spectral signal generated by the interaction between the laser and the metal material during the welding process, as well as the melting transfer process of the welding wire, can be detected by a plasma spectrometer and a camera, so as to achieve the purpose of observing and controlling the melting transfer behavior of the laser wire welding droplet under different ambient pressures, the correlation and connection between the interaction behavior of the molten droplet and the ambient pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0038] In the attached picture:

[0039] Figure 1 is a schematic diagram of an apparatus according to an embodiment of the present invention;

[0040] Figure 2 is a schematic diagram of the laser transmission window;

[0041] Figure 3 is a schematic diagram of a mobile device sample of the present invention;

[0042] Figure 4 Schematic diagram of nano-metal particle beam flow in the welding process of coated transparent quartz glass;

[0043] Figure 5Schematic diagram of the sample;

[0044] Figure 6 The effect of ambient pressure on the weld and cross-sectional macroscopic morphology of 304 stainless steel laser wire welding;

[0045] Figure 7 The effect of ambient pressure on nano-metal particles inside and outside the beam path during laser wire welding of 304 stainless steel;

[0046] Figure 8 This is the effect of ambient pressure on the plasma and metal melting transfer process in pulsed laser welding of 304 stainless steel;

[0047] Fig. 9 This is the effect of ambient pressure on the plasma spectrum during laser wire welding of 304 stainless steel;

[0048] In the above figure: 1 is a laser welding head, 2 is a laser transmission window, 3 is a high-pressure cavity, 4 is an observation window, 5 is a wire feeding pulley group, 6 is a camera, 7 is a linear movable slide, 8 is a plasma spectrometer, 9 is an argon gas bottle, 10 is a back pressure valve, 11 is a wire feeding nozzle, 12 is a sample, 13 is a pressure reducing valve, 14 is a first rubber ring, 15 is quartz glass, 16 is a quartz glass sheet, 17 is a second rubber ring, 18-1 is a sealing groove, 18-2 is a light-transmitting hole, 19 is a motor, 20 is a movable slide transmission wheel group, 21 is a movable slider, 22 is a guide rail, 23 is a metal vapor particle, and 24 is a filter.

[0049] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0050] The following will refer to the attached Figures 1 to 9 Specific embodiments of the present invention are described in more detail. Although specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0051] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.

[0052] To facilitate understanding of the embodiments of the present invention, further explanation will be given below by taking specific embodiments as examples in conjunction with the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0053] For a better understanding, Figures 1 to 9 As shown, a device for controlling laser wire welding droplets based on environmental pressure changes includes: a camera 6 capable of high-speed photography, a plasma spectrometer 8 and a high-pressure chamber 3, an argon gas bottle 9, a laser welding head 1, a pressure reducing valve 13, a back pressure valve 10, and an electric wire feeding pulley group 5 arranged inside the high-pressure chamber 3, a wire feeding remote control trigger module, a miniature linear moving slide 7, a slide remote control trigger module, a light-transmitting quartz glass 15, and a quartz glass sheet 16.

[0054] The welding pre-treatment process includes: coupling the wire feeding remote control trigger module and the slide remote control trigger module with the laser welding head respectively to ensure that the three can be triggered at the same time; fixing the wire feeding nozzle 11 of the electric wire feeding pulley group at a suitable position inside the high-pressure chamber 3; fixing the sample on the moving slider 21 of the miniature linear moving slide 7 and adjusting the position; a laser transmission window 2 is provided on the top of the high-pressure chamber 3, and an observation window 4 is provided in front of the high-pressure chamber 3, and the camera 6 is aligned with the observation window 4, and the plasma spectrometer 8 is kept at a 45-degree angle to the laser transmission window 2.

[0055] The light-transmitting quartz glass 15 is located directly above the sample 12 , and the laser emitted by the laser welding head 1 passes through the laser transmission window 2 and the light-transmitting quartz glass 15 and irradiates onto the sample 12 .

[0056] The outlet of the argon gas cylinder 9 is connected to the high-pressure chamber 3 at the side through the pressure reducing valve 13 and the pipeline I.

[0057] In one embodiment, the laser transmission window 2 at the top of the high-pressure cavity 3 is divided into a sealing groove 18-1 and a light-transmitting hole 18-2, which are distributed in sequence from the outside to the inside. The light-transmitting window provided on the cover plate 3-1 is substantially the same as the laser transmission window 2 at the top of the high-pressure cavity 3, and the size difference between the two does not exceed 10%. A sealing groove and a light-transmitting hole are provided at the bottom thereof. The sealing grooves provided on the laser transmission window 2 at the top of the high-pressure cavity 3 and the light-transmitting window at the top of the cover plate 3-1 are respectively provided with a first rubber ring 14 and a second rubber ring 17. The upper side of the highly pure quartz glass 15 coated with a film is located in the light-transmitting glass groove of the laser transmission window 2 at the top of the high-pressure cavity 3, and its upper surface contacts the first rubber ring 14. The lower surface of the quartz glass 15 contacts the upper surface of the quartz glass sheet 16. The lower surface of the quartz glass sheet 16 contacts the second rubber ring located in the sealing groove 18-1 provided on the cover plate.

[0058] 17 Contact.

[0059] In one embodiment, a gas outlet II with a back pressure valve 10 is provided on the side of the high pressure chamber 3. A filter 25 is provided between the camera 6 of a high speed camera and the observation window 4. The transmittance of the quartz glass 15 to the 1070 nm fiber laser is greater than or equal to 95%. The level control of the welding environment pressure is monitored and controlled by the pressure reducing valve 13 installed at the argon gas bottle 9.

[0060] In one embodiment, gas is continuously introduced or extracted during the welding process to ensure the dynamic balance of gas flow inside the cavity to maintain the ambient pressure level. The pressure level control range is 50Pa-2.0MPa, within which the internal pressure of the high-pressure cavity 3 can be stably maintained; during the welding process, the tooling, laser and wire feeding positions are kept unchanged, and the movement of the moving slider in a certain direction is achieved through a miniature linear moving slide, and its welding size is related to the internal space size of the high-pressure cavity; cable-type welding wire is used during welding, and the welding wire should not be preset too long in a narrow space, so as to improve the laser absorption efficiency, increase the metal cladding rate and increase the welding wire stiffness; the wire feeding remote control trigger module, the remote control slide trigger module and the laser emission are linked, and the three can be triggered at the same time; the linear moving slide 7 can adjust the height in the direction of gravity; with the change of pressure P, the change of weld penetration H meets the characteristic H=6.5*P^(-0.264), and with the change of pressure P, the change of droplet transition T period meets the characteristic T=36.4+0.24*P.

[0061] In one embodiment, the form of droplet transition changes with the change of ambient pressure. Under negative pressure, the droplets present small particle droplet transition and liquid bridge transition, and under high pressure, the droplets present large particle droplet transition.

[0062] In one embodiment, the device includes an argon gas bottle 9, a laser welding head 1, a pressure reducing valve 13, a camera 6, a plasma spectrometer 8, a wire feeding pulley group 5, a wire feeding nozzle 11, a miniature linear movable slide 7, a high-pressure chamber 3, and a quartz glass 15 and a quartz glass sheet 16 inside the high-pressure chamber 3; the miniature linear movable slide 7 is fixed inside the high-pressure chamber 3, and the electric wire feeding pulley group 5 is installed inside the high-pressure chamber 3, and the wire feeding nozzle 11 is fixed in a position to ensure that the welding wire is sent out and intersects with the laser beam at a suitable position, and the wire feeding pulley group 5 is fixed in a position to ensure that the welding wire is sent out and intersects with the laser beam at a suitable position. The cable is fastened by an armored sealing head. A laser transmission window 2 is provided on the top of the high-pressure cavity 3, and an observation window 4 is provided on the front side. A high-speed camera 6 is aimed at the front observation window 4, and a plasma spectrometer 8 is aimed at the top transmission window at a certain deflection angle. The quartz glass 15 and the quartz glass sheet 16 are located directly above the sample. The laser passes through the laser transmission window 2, the quartz glass 15 and the quartz glass sheet 16 and irradiates the welding wire 25 and the sample 12. The outlet of the argon gas bottle 9 is connected to the high-pressure cavity 3 through the pressure reducing valve 13. The laser transmission window 2 at the top of the high-pressure cavity is divided into a sealing groove 18-1 and a light transmission hole 18-2, which are distributed in sequence from the outside to the inside. The light transmission window set on the cover plate is roughly the same as the laser transmission window at the top of the high-pressure cavity, and a sealing groove and a light transmission hole are set at the bottom. The sealing grooves set on the laser transmission window 2 at the top of the high-pressure cavity 3 and the light transmission window at the top of the cover plate are respectively equipped with a first rubber ring 14 and a second rubber ring 17. The upper surface of the quartz glass 15 contacts the first rubber ring 14, and its lower surface contacts the upper surface of the quartz glass sheet 16, and the lower surface of the quartz glass sheet 16 contacts the second rubber ring 17.

[0063] The side of the high-pressure cavity is provided with an outlet II with a back pressure valve 10. A filter 24 is provided between the high-speed camera 6 and the observation window 4. The transmission of the quartz glass 15 and the quartz glass sheet 16 to the 1070nm fiber laser is greater than or equal to 95%.

[0064] The welding wire used in the laser wire-filling welding is a twisted wire 25. The gaps between the welding wires allow the laser to be reflected multiple times, which is beneficial to improving energy utilization.

[0065] In one embodiment, an air inlet I and an air outlet II are respectively provided on the left and right sides of the high-pressure cavity. The air outlet of the argon gas bottle 9 is connected to the pressure reducing valve 13, and is connected to the air inlet I on one side of the high-pressure cavity through a gas pipeline. The gas is filled into the high-pressure cavity. When the back pressure valve 10 on the other side is closed, the cavity pressure is increased. When the back pressure valve 10 is opened, the gas is released and the pressure is reduced. A laser transmission window 2 is provided on the top of the high-pressure cavity 3. The welding laser head 1 is directly facing the laser transmission window 2 on the top of the high-pressure cavity. The laser beam emitted by the welding laser head enters the transmission hole, passes through the quartz glass 15 and the quartz glass sheet 16, enters the high-pressure cavity 3, and irradiates the junction of the sample 12 and the welding wire 25. Welding; an observation window 4 is arranged on the front of the high-pressure chamber 3, a high-speed camera 6 is aimed at the front observation window 4, and a plasma spectrometer 8 is aimed at the laser incident window 2 at a certain angle to collect the plasma emitted light beam; a miniature linear movable slide 7 and a miniature wire feeding pulley group 5 are arranged inside the high-pressure chamber 2, the miniature linear movable slide 7 is provided with a movable slider 21 and a guide rail 22, a stainless steel sample 12 is placed on the movable slider 21, and can move with the slider, and the miniature wire feeding pulley group 5 is equipped with a copper wire feeding nozzle 11, which can complete the wire feeding process, and the two are respectively configured with a wire feeding remote control trigger module and a mobile remote control trigger module.

[0066] The top of the high-pressure cavity is provided with a laser transmission window 2, which is mainly composed of a light-transmitting hole 18-2 and a sealing groove 18-1. The first rubber ring 14 is placed in the sealing groove in the transmission window and directly contacts the upper surface of the quartz glass 15. The lower surface of the quartz glass sheet contacts the upper surface of the quartz glass sheet 16. The thin quartz glass sheet directly contacts the second rubber ring 17 placed in the sealing groove of the cover plate. The two sides of the high-pressure cavity 3 are respectively provided with an air inlet I and an air outlet II with a back pressure valve 10; the camera 6 is aimed at the observation window, and there is a filter 24 between the two.

[0067] The control method comprises the following steps,

[0068] 1. Connect the argon gas bottle 9 to the pressure reducing valve 13, and connect it to the gas inlet I on the side of the high-pressure tooling 3 through the connecting pipe;

[0069] 2. Place the micro wire feeding pulley assembly 5 and the micro linear moving slide 7 inside the high pressure chamber 3, and fix the welding wire 25 and the sample 12 to be welded on the moving slide 21;

[0070] 3. Tighten and install the transmission window 2-first rubber ring 14-quartz glass 15-quartz glass sheet 16-second sealing rubber ring 17-cover plate 3-1 in the following order and keep them sealed;

[0071] 4. Tighten the cover plate 3-1, align the welding laser head 1 with the laser transmission window 2, and align the center of the laser beam spot with the joint position of the welding wire 25 and the sample 12;

[0072] 5. Open the argon gas bottle 9 and the pressure reducing valve 13, close the back pressure valve 10, and keep it for 30 seconds. Open the back pressure valve 10 to exhaust the air inside the high pressure chamber 3 for one minute, then close the back pressure valve 10 and start to inflate. Adjust the pressure reducing valve 13 to make the pressure inside the high pressure chamber 3 reach the required level.

[0073] 6. Install the high-speed camera 6 and the plasma spectrometer 8, aim the high-speed camera 6 at the observation window 4, and aim the plasma spectrometer 8 at the laser transmission window 2 at an angle of 45 degrees;

[0074] 7. After completing the preparation work, start welding and collect the required information at the same time. After welding, maintain the argon environment until the sample cools down and remove the sample.

[0075] The method can realize a pressure device with stepless pressure change, which has the characteristics of small size, easy operation and stepless pressure change. Compared with the existing pressure vessels, the stepless pressure change is a major feature of this equipment. It also has a certain working space to pre-set a certain length of welding wire and perform laser wire filling welding. Through this test device, the environmental pressure level in the welding process can be adjusted at any time to control the molten droplet transition behavior and the forming characteristics of the weld.

[0076] In one embodiment, the sample 12 and the welding wire 25 of the experiment are both 304 stainless steel, and the stainless steel sample 12 and the welding wire 25 are in contact. In the actual welding process, the sample 12 and the welding wire 25 are firstly polished to remove the oxide scale, and then wiped with alcohol, and then the stainless steel sample 12 is placed on the moving slider 21, and a part of the welding wire is preset to be close to the sample surface, and at the same time, the light-transmitting quartz glass 15 and the quartz glass sheet 16 are placed just above the sample, and the glass is fixed and sealed by using the first rubber ring 14 and the second rubber ring placed in the sealing groove. , then make the spot center of the laser welding head coincide with the junction of the sample and the welding wire, with half of the spot on the sample and half on the welding wire, seal the laser transmission window 2 and the front observation window 4 on the top of the high-pressure chamber, close the back pressure valve 10, open the argon gas bottle 9 and the pressure reducing valve 13, wait for 30 seconds, then open the back pressure valve 10 to exhaust the air inside the high-pressure chamber, the exhaust process lasts for one minute, then close the back pressure valve 10 and start to inflate the high-pressure chamber, so that the pressure inside the high-pressure chamber reaches the required ambient pressure, and then close the argon gas bottle 9 and the pressure reducing valve 13;

[0077] Turn on the high-speed camera 6 and the plasma spectrometer 8, and complete the focus adjustment and other operations of the high-speed camera 6, turn on the plasma spectrometer 8 to complete the dark field calibration operation, and fix the two to the corresponding positions, align the center of the laser beam spot with the contact position of the welding wire 25 and the sample 12 to perform welding; add a filter 24, take pictures through the high-speed camera 6, detect and record the electron density of the plasma and the sample temperature through the plasma spectrometer 8, and collect the metal vapor particles 23 through the quartz glass sheet 16;

[0078] After the sample welding is completed, the argon environment is maintained for a period of time until the sample cools down, the back pressure valve 10 is opened to release the gas inside the high pressure cavity 3, so that the environment of the high pressure cavity reaches normal pressure, and then the sample is taken out.

[0079] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific embodiments and application fields, and the above specific embodiments are only illustrative and instructive, rather than restrictive. A person of ordinary skill in the art can also make many forms under the guidance of this specification and without departing from the scope of protection of the claims of the present invention, all of which belong to the protection of the present invention.

Claims

1. A device for controlling laser wire welding droplets based on environmental pressure changes, characterized in that: These include, a laser welding head that controllably emits a laser beam; A high pressure chamber comprising: An air inlet, which is provided at one end of the high-pressure cavity and can be connected to the argon gas cylinder in an on-off manner; An air outlet, which is arranged at the other end of the high-pressure cavity away from the air inlet, and the air outlet and the air inlet regulate the high-pressure cavity to be at a pressure p; an observation window, which is visually arranged on the high-pressure chamber; A laser transmission window, which is disposed in the high-pressure cavity and aligned with the laser welding head to introduce the laser beam; Quartz glass, located on a side of the laser projection window opposite to the laser welding head; A quartz glass sheet, which is connected to the side of the quartz glass opposite to the quartz glass in a liftable manner to collect metal vapor nanoparticles generated during laser welding at different heights; A linear moving slide is arranged in the high pressure chamber, and the linear moving slide comprises: a guide rail extending within the high pressure chamber; A movable slider, which is slidably connected to the guide rail, and the sample is supported on the movable slider to move to a welding position; A wire feeding pulley assembly, which is arranged in the high-pressure chamber to transport the welding wire to the welding position; A camera facing the observation window to capture image information of the welding process; a plasma spectrometer, which is aligned with the laser transmission window at a predetermined angle to collect spectral signals generated during the welding process; A processor is connected to the high-pressure chamber, the camera and the plasma spectrometer, and is used to adjust the pressure in the high-pressure chamber based on the image information and the spectral signal.

2. The device for controlling laser wire welding droplets based on environmental pressure changes according to claim 1 is characterized in that: Preferably, the image information includes the size of plasma generated during welding, information on the melting state of the welding wire and / or the number range of metal vapor nanoparticles.

3. The device for controlling laser wire welding droplets based on environmental pressure changes according to claim 1 is characterized in that: The gas inlet is connected to an argon gas cylinder via a pressure reducing valve, and the pressure reducing valve is connected to the processor.

4. The device for controlling laser wire welding droplets based on environmental pressure changes according to claim 1, characterized in that: The gas outlet is provided with a back pressure valve, and the back pressure valve is connected to the processor.

5. The device for controlling laser wire welding droplets based on environmental pressure changes according to claim 1, characterized in that: The linear movable slide is adjustable in height direction.

6. The device for controlling laser wire welding droplets based on environmental pressure changes according to claim 1, characterized in that: The linear movable slide includes a motor for driving the movable slider, the motor is wirelessly connected to the slide remote control trigger module, the wire feeding pulley group is wirelessly connected to the wire feeding remote control trigger module, and the wire feeding remote control trigger module is respectively coupled with the laser welding head so that the sample, welding wire and laser beam are triggered simultaneously.

7. The device for controlling laser wire welding droplets based on environmental pressure changes according to claim 1, characterized in that: The pressure p is 50Pa-2.0MPa, and the predetermined angle is 45 degrees.

8. The device for controlling laser wire welding droplets based on environmental pressure changes according to claim 1, characterized in that: The processor adjusts the welding process so that the weld penetration H changes with the pressure P, H=6.5*P^(-0.264), and the droplet transition T period T changes with the pressure P to T=36.4+0.24*P.

9. The device for controlling laser wire welding droplets based on environmental pressure changes according to claim 1, characterized in that: A filter is arranged between the camera and the observation window, and the transmittance of the quartz glass to the 1070nm fiber laser is greater than or equal to 95%.

10. A control method for a device for controlling a laser wire welding droplet based on an environmental pressure change as claimed in any one of claims 1 to 9, characterized in that: It includes the following steps, The sample is placed on a moving slide to move to a welding position with the movement and a wire feeding pulley group delivers welding wire to the welding position, and the welding position is directly below the quartz glass sheet; The laser welding head emits a laser beam toward the welding position, the spot center of the laser beam coincides with the junction of the sample and the welding wire, half of the spot is on the sample, and the other half is on the welding wire; The camera captures image information of the welding process, and the plasma spectrometer collects spectral signals generated during the welding process. The pressure in the high-pressure chamber is adjusted based on the image information and spectral signals, so that the laser wire welding droplets in the welding process can be controlled.

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