CN118808888A - A low-spatter laser welding method and device - Google Patents

Abstract

The present application relates to the field of laser welding technology, and specifically to a low-spatter laser welding method and a laser welding device. The laser welding method includes: shaping the laser beam to form a light spot with different energy distribution areas, and the different energy distribution areas of the light spot are used for preheating and welding respectively. By using a laser welding method provided by the present application, the shape of the light spot and the energy distribution of the laser beam are changed after shaping, and the welds on the working area are preheated and welded through different energy distribution areas, which can reduce the rapid evaporation and spatter caused by the concentration of heat energy during the welding process, stabilize the molten pool, and reduce the generation of metal vapor. The technical solution of the present application solves the problem of large spatter in the existing welding solution.

Description

A low-spatter laser welding method and device

Technical Field

The present application relates to the technical field of laser welding, and in particular to a low-spatter laser welding method and device thereof.

Background Art

The laser welding device is a high-precision welding tool that combines laser technology and welding technology. Laser radiation heats the surface of the workpiece, and the surface heat diffuses to the inside through heat conduction. By controlling the width, energy, peak power, and repetition rate of the laser pulse, the workpiece is melted and a specific molten pool is formed.

However, the laser welding devices in the prior art are prone to spatter when used in actual scenarios. Spatter refers to the droplets of molten metal ejected from the molten pool during the welding process. These droplets may fall on the surrounding work surface, resulting in a rough and uneven workpiece surface, and may even cause a loss of molten pool quality, such as pits and blast spots on the weld surface, which ultimately leads to poor welding results and affected weld quality performance.

Therefore, the present application specifically proposes a low-splash laser welding method and device thereof to solve the spatter phenomenon generated when welding workpieces in the prior art.

Summary of the invention

In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a low-spatter laser welding method and device thereof, which are used to solve the problems of large spatter and poor molten pool stability in existing welding solutions.

To achieve the above purpose, the technical solution adopted in this application is:

A low-spatter laser welding method, comprising:

The laser beam is shaped to form a light spot with different energy distribution areas, and the different energy distribution areas of the light spot are used for preheating and welding respectively.

As a preferred solution, the spot shape after shaping is different from the spot shape of the original laser beam.

As a preferred solution, the spot shape formed by the shaped laser beam is non-circular, and at least part of the energy gradually decreases along the processing direction.

As a preferred solution, the energy used for preheating of the light spot accounts for 2%-25% of the total energy of the light spot, and the energy used for welding accounts for 75%-98% of the total energy of the light spot.

As a preferred embodiment, shaping the laser beam further includes: using a collimator and a focusing mirror to shape the divergent laser beam, the main optical axis of the collimator intersects with the central axis of the divergent light beam and is set at a preset angle, and the main optical axis of the focusing mirror coincides with the central axis of the laser beam; or, the main optical axis of the collimator and the main optical axis of the focusing mirror respectively intersect with the central axis of the divergent light beam and are set at a preset angle.

As a preferred solution, it also includes: using a focusing mirror to shape the collimated laser beam, and the main optical axis of the focusing mirror intersects with the central axis of the collimated beam and is arranged at a preset angle.

As a preferred solution, the preset angle ranges from 1.5° to 4°.

As a preferred solution, the low-spatter laser welding method further comprises: using a beam splitting component to split the shaped laser beam, and after the beam splitting, forming a preheating beam and a welding beam in a predetermined ratio.

As another aspect of the present application, the present application also proposes a laser welding device for executing the laser welding method of any of the above-mentioned schemes, the laser welding device includes a laser emission source and a beam shaping element arranged in sequence along the light beam emission direction, wherein the laser emission source is used to emit a laser beam; the beam shaping element is used to shape the laser beam to form a light spot with different energy distribution areas.

As a preferred solution, the laser welding device is used to weld materials with a plate thickness between 2mm and 6mm.

Different from the prior art, the embodiment of the present application provides a low-spatter laser welding method and device thereof, the laser welding method comprising: shaping the laser beam to form a light spot with different energy distribution areas, the different energy distribution areas of the light spot are used for preheating and welding respectively. By adopting a laser welding method provided by the present application, the shape of the light spot and the energy distribution of the laser beam are changed after shaping, and the weld on the working area is preheated and welded through different energy distribution areas, which can reduce the rapid evaporation and spatter caused by the concentration of heat energy during hand-held welding, stabilize the molten pool, and reduce the generation of metal vapor; in the laser welding device of the present application, the beam shaping element (i.e., the collimator and the focusing lens/focusing lens) is arranged at the beam input end of the beam reflecting element, that is, the laser is shaped and converged before reflection, and by arranging the focusing lens at the rear end of the welding device, it is helpful to prevent the splashes at the nozzle from flowing back and causing damage to the focusing lens.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

FIG1 is a schematic diagram of an optical path inside a laser welding device according to an embodiment of the present application;

FIG2 is a schematic diagram of the light spot shape when the angle between the main optical axis of the collimating mirror and the central axis of the laser beam is 3.2° and the main optical axis of the focusing mirror is coaxial with the central axis of the laser beam;

FIG3 is a schematic diagram of the light spot shape when the angle between the main optical axis of the collimating mirror and the central axis of the laser beam is 2.2° and the main optical axis of the focusing mirror is coaxial with the central axis of the laser beam;

FIG4 is a schematic diagram of the light spot shape when the main optical axis of the collimating mirror of the present application is coaxial with the central axis of the laser beam and the angle between the main optical axis of the focusing mirror and the central axis of the laser beam is 4.9°;

FIG5 is a schematic diagram of the light spot shape when the main optical axis of the collimating mirror of the present application is coaxial with the central axis of the laser beam and the angle between the main optical axis of the focusing mirror and the central axis of the laser beam is 3.1°;

FIG6 is a schematic diagram of a laser welding device in one embodiment of the present application;

FIG. 7 is a schematic diagram of the optical path inside a laser welding device in another embodiment of the present application.

Description of reference numerals: 100, first connecting portion; 110, optical fiber; 120, end cap; 130, collimator; 140, focusing lens; 150, first spacer; 160, second spacer; 170, beam splitter; 1, main optical axis of collimator; 12, main optical axis of focusing lens;

200, second connecting part; 201, first part; 202, second part; 210, protective mirror; 220, rod body; 230, nozzle;

310, reflector; 320, lens clip; 330, actuator.

DETAILED DESCRIPTION

In order to facilitate the understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on another element, or there can be one or more centered elements therebetween. When an element is described as "electrically connected" to another element, it can be directly connected to another element, or there can be one or more centered elements therebetween. The orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "bottom", etc. used in this specification is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and/or" used in this specification includes any and all combinations of one or more of the related listed items.

In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

At present, when laser welding equipment is used to continuously weld the parent material, due to the rapid temperature rise of the welded workpiece, serious spatter is easily generated at the welding part, which further causes pit defects and deformation on the welding surface, and the welding effect is not ideal. In addition, the main shaping element (focusing mirror) in the laser welding device is usually set at the output end of the reflector. The debris formed by the spatter is easy to flow back from the nozzle into the device and directly damage the focusing mirror, resulting in high repair costs.

Based on the above problems, the present application provides a low-splash laser welding method and a laser welding device. With this welding method, not only can the welding part of the working area be directly preheated and welded with high quality through the spot formed by a single light beam, but also the area with lower energy on the spot is used to heat the base material and expand the keyhole opening, and the area with higher energy is used to penetrate the metal and achieve deep fusion welding. The two cooperate with each other to reduce the spatter generated at the welding part of the working area to avoid pit defects and welding deformation; at the same time, the present application also sets the shaping element at the beam input end of the reflector, so that even if the external spatter flows back into the device, it cannot directly damage the shaping element, which is conducive to improving the safety of the device.

A low-spatter laser welding method proposed in the present application specifically comprises the following steps: shaping the laser beam to form a light spot with different energy distribution areas, wherein the different energy distribution areas of the light spot are used for preheating and welding respectively.

In the actual welding process, the laser welding method of the present application is used. The area on the spot used for preheating first reaches the welding part on the working area. As the light beam scans, the preheating area gradually moves forward along the welding path. The welding area of the spot reaches the part of the preheating area that has been preheated before, and penetrates the metal to achieve deep fusion welding. It can be understood that the spot shape and energy distribution of the laser beam after shaping are changed. Preheating and welding the weld on the working area through different energy distribution areas can not only reduce the rapid evaporation and spattering caused by the concentration of heat energy during handheld welding, stabilize the molten pool, reduce the occurrence of metal vapor, but also help protect the shaping elements in the device from damage by backflow and spatter.

It is understandable that the spot shape after shaping is different from the spot shape of the original laser beam. Before shaping, the laser beam is emitted from a point light source, and its spot shape (and the radial cross-sectional shape of the laser beam) is circular. After shaping, the spot shape of the laser beam is different from the aforementioned circle, and at least part of the energy gradually decreases along the processing direction.

For example, please refer to any one of Figures 2 to 5. The spot formed by the shaped laser beam has an extension tendency, such as a teardrop shape or an ellipse, and the working area can be preheated and welded in different areas according to energy partitioning.

Preferably, in order to achieve a better welding effect, the energy used for preheating of the spot accounts for 2%-25% of the total energy of the spot, and the energy used for welding accounts for 75%-98% of the total energy of the spot. Under such an energy distribution ratio, the energy at the edge of the spot drops sharply, and the energy area used for preheating is distributed around the energy area used for welding, that is, with the swing of the light beam, the weld in the working area can be welded only after sufficient preheating, which can make the laser energy distribution of the spot in the width scanning direction more uniform, which is more conducive to forming a flat and uniform cladding layer, reducing spatter generated during welding, and further improving the welding effect.

It is understood that in the technical solution of the welding method of the present application, the solutions that can be used for laser beam shaping include but are not limited to the following embodiments:

When the laser beam is a divergent beam, a collimator and a focusing lens are used to shape the laser beam. The main optical axis of the collimator intersects with the central axis of the laser beam and is set at a preset angle, and the main optical axis of the focusing lens coincides with the central axis of the laser beam. Please refer to Figure 1 for details. After the laser beam passes through the collimator set at a preset angle relative to its central axis, it is shaped into a first astigmatic beam. By configuring a specific tilt angle with the collimator, the energy distribution in the diffuse light spot can be controlled to form a light spot with different energy distribution areas. In an embodiment of the present application, the first astigmatic beam collimated and shaped by the collimator continues to be incident on the focusing lens, and the main optical axis of the focusing lens coincides with the central axis of the original laser beam. Therefore, based on the same principle, the first astigmatic beam further forms a second astigmatic beam after passing through the focusing lens, and at the same time, a light spot with different energy density distribution areas is formed at the focal plane of the focusing lens. It should be noted that the second astigmatic beam no longer forms a point image, but forms an asymmetric diffuse light spot with a shrinking trend.

Alternatively, when the laser beam is a divergent beam, a collimator and a focusing lens are used to shape the laser beam, and the main optical axis of the collimator and the main optical axis of the focusing lens respectively intersect with the central axis of the divergent beam and are set at a preset angle. This embodiment is based on the same principle as the aforementioned embodiment, so it is not repeated here. The angle formed by the main optical axis of the collimator and the central axis of the divergent beam is a first preset angle, and the angle formed by the main optical axis of the focusing lens and the central axis of the divergent beam is a second preset angle. It should be noted that the first preset angle can be the same or different. It can be understood that after the technicians in this field make a reasonable optical path design according to the actual situation, the two angles being the same or different can make the optical path finally output light spots with different energy distribution areas, so as to preheat and weld the welds in the working area.

When the laser beam is a collimated beam, a focusing mirror is used to shape the laser beam, and the main optical axis of the focusing mirror intersects with the central axis of the collimated beam and is arranged at a preset angle.

Preferably, in the above scheme, the preset angle formed by the intersection of the main optical axis of the optical lens and the main optical axis of the laser beam is 1.5°-4°. It has been verified by simulation that when the angle is within the above range, the energy used for preheating and the energy used for welding are more ideal, the temperature of the molten pool is more uniform, and the effect of suppressing welding spatter is significantly improved. In actual application, the offset angle of the lens can be appropriately adjusted according to the thickness of the parent material, and the optical path design method is more flexible and changeable. It can be understood that after the technicians in this field make a reasonable optical path design according to the actual situation, the two angles are the same or different, which can make the optical path finally output light spots with different energy distribution areas, so as to preheat and weld the welds in the working area.

Please refer to FIG. 2 to FIG. 5 , which respectively show schematic diagrams of the shapes of light spots after final shaped reflection in different embodiments.

When the angle between the main optical axis l1 of the collimator and the central axis of the laser beam is 3.2°, and the main optical axis l2 of the focusing mirror is coaxial with the central axis of the laser beam, the overall light spot is in the shape of a water droplet, and the energy in the area used for preheating accounts for about 80% of the total energy of the light spot, as shown in Figure 2.

When the angle between the main optical axis l1 of the collimator and the central axis of the laser beam is 2.2°, and the main optical axis l2 of the focusing mirror is coaxial with the central axis of the laser beam, the overall light spot is in the shape of a water droplet, and the energy in the area used for preheating accounts for about 90% of the total energy of the light spot, as shown in Figure 3.

When the main optical axis l1 of the collimating mirror is coaxial with the central axis of the laser beam, and the main optical axis l2 of the focusing mirror is at an angle of 4.9° with the central axis of the laser beam, the overall light spot is drop-shaped, and the energy of the area used for preheating accounts for about 85% of the total energy of the light spot, as shown in Figure 4.

When the main optical axis l1 of the collimating mirror is coaxial with the central axis of the laser beam, and the main optical axis l2 of the focusing mirror is at an angle of 3.1° with the central axis of the laser beam, the light spot is elliptical as a whole, and the energy of the area used for preheating accounts for about 95% of the total energy of the light spot, as shown in FIG5 .

By reasonably setting the angle between the main optical axis of the optical lens and the main optical axis of the laser beam, the present application provides a better preheating effect for the weld while also obtaining a better focused spot at the focal plane, relative to the solution in which the lens is set perpendicular to the optical axis of the incident light beam.

In an ideal optical system, it is usually assumed that the lens is a thin lens, and the main optical axis of the optical lens is usually coaxial with the central axis of the light beam, so that the output light beam can be correctly focused or collimated, thereby achieving a good focusing effect. However, in fact, the lens has a certain thickness, which will lead to differences between the optical theoretical model and the actual light propagation process, and it cannot be guaranteed that the main optical axis of the lens completely coincides with the central axis of the light beam, which is easy to cause coma. The design idea of the present application is to control the angle between at least one of the collimating lens and the focusing lens and the main optical axis of the incident light beam, and to achieve changes in the shape of the light spot and the partitioning of the energy under the premise of controllable coma, so as to preheat and weld the welds on the working area.

Furthermore, the low-spatter laser welding method of the present application further includes: using a beam splitter component to split the shaped laser beam, and after the beam splitting, a preheating beam and a welding beam are formed according to a predetermined ratio. Among them, the preheating beam is reflected to the working plane by the beam splitter of the beam splitter component to form a fixed-point light spot, and the welding beam is transmitted through the beam splitter of the beam splitter component, and further reflected to the working area by the reflector 310 to form a welding light spot. Please refer to Figure 7. The preheating beam first reaches the welding part on the working area, and gradually preheats the welding part in the first stage. After that, the welding beam reaches the welding part, and the low-energy distribution area of its light spot continues to preheat it in the second stage. Finally, the high-energy distribution area reaches the previously preheated part and penetrates the metal to achieve deep fusion welding.

By providing such a laser welding method, the present application can change the spot shape and beam energy of the divergent beam/collimated beam after passing through the beam shaping element. The weld is preheated and welded through areas corresponding to different energies, which can reduce rapid evaporation and spattering caused by heat concentration during handheld welding, stabilize the molten pool, and reduce the generation of metal vapor. The shaped beam can be further divided into a preheating beam and a welding beam. The weld on the working area is preheated through the low-energy distribution area of the preheating beam and the welding beam, which can not only reduce rapid evaporation and spattering caused by heat concentration during the formal welding process, stabilize the molten pool, reduce the generation of metal vapor, but also help protect the shaping elements in the device from damage by backflow and spatter. The energy distribution of the processing beam spot finally obtained by the method of the present application is optimized and no longer focused on a single point, ensuring uniform heating.

As another aspect of the present application, the present application also proposes a laser welding device, which is used to perform the welding method in any of the above schemes. The welding device includes a laser emission source and a beam shaping element arranged in sequence along the light beam emission direction. The laser emission source is used to emit a laser beam; and the beam shaping element is used to shape the laser beam to form a light spot with different energy distribution areas.

Please refer to Figure 6, which provides a three-dimensional schematic diagram of the laser welding device in one embodiment. The welding device is now described as a laser welding gun. At this time, the laser welding device also includes a beam reflecting element arranged at the laser emitting end of the beam shaping element.

In some embodiments, the laser emission source may adopt the following structures. For example, when the laser emission source is used to emit a divergent light beam, it includes an optical fiber 110 and an end cap 120 arranged in sequence. One end of the optical fiber 110 is connected to the laser, and the other end is fused to the end cap 120. At this time, the beam shaping element includes a collimator 130 and a focusing lens 140, the main optical axis of the collimator 130 intersects with the central axis of the divergent light beam at a preset angle, and the focusing lens 140 is arranged between the collimator 130 and the light beam reflecting element, and the focusing lens 140 is coaxial with the divergent light beam.

Alternatively, when the laser emission source is used to emit a collimated light beam, it includes an optical fiber, an end cap, and a collimator lens arranged in sequence, one end of the optical fiber is connected to the laser, the other end of the optical fiber is fused to the end cap, and the collimator lens is arranged at the output end of the end cap. In this case, the beam shaping element includes a focusing lens, and the main optical axis of the focusing lens intersects with the central axis of the collimated light beam at a preset angle.

Alternatively, when the laser emission source is used to emit a collimated light beam, it includes an optical fiber and a collimating end cap arranged in sequence, one end of the optical fiber is connected to the laser, and the other end is fused to the collimating end cap. At this time, the beam shaping element includes a focusing mirror, and the main optical axis of the focusing mirror intersects with the central axis of the collimated light beam at a preset angle. Exemplarily, the collimating end cap may adopt the structure in patent application number 2021115238008. It can be understood that the use of the collimating end cap is conducive to reducing the number of optical components in the optical path, thereby simplifying the assembly and adjustment of components, and is conducive to lightweight design using the laser welding device of the optical system.

Please continue to refer to Figure 6, and the technical solution of the present application will be further described by taking the laser emission source including the optical fiber 110, the end cap 120 and the collimator 130, and the beam shaping element including the focusing lens 140 as an example. The first end of the optical fiber 110 is connected to the laser, the second end of the optical fiber 110 is fused to the end cap, and the end cap 120, the collimator 130 and the focusing lens 140 are optically connected in sequence; the main optical axis of the beam shaping element intersects with the central axis of the collimated light beam emitted from the laser emission source at a preset angle.

Preferably, the laser emission source and the focusing lens 140 are both installed inside the hollow sleeve, and a light passage is provided inside the hollow sleeve. The laser emission source is fixedly arranged at the first end of the axial direction of the hollow sleeve by a fixing member to form a closed interval from the optical fiber 110 to the laser output. It can be understood that the first end is usually arranged near the output end of the laser light source (that is, the laser), and a mounting groove is provided, and the fixing member abuts against the laser emission source to seal the laser emission source inside the stepped hole of the light passage. Specifically, the end of the laser emission source away from the focusing lens 140 is connected to the optical fiber armor cable of the laser through an optical fiber, and the laser output by the laser is transmitted to the laser emission source through an optical cable and an optical fiber and then shaped and collimated. A focusing lens barrel (not shown in the figure) is also movably installed in the hollow sleeve, and the focusing lens 140 is installed in the focusing lens barrel. In order to further reduce the installation error of the laser emission source, the fixing member used to fix the laser emission source can adopt an elastic pressure ring.

Please continue to refer to FIG6 . The laser welding device of the present application further includes a first connecting part 100 and a second connecting part 200. The laser emission source and the beam shaping element are detachably installed inside the first connecting part 100. A first installation cavity is provided inside the first connecting part 100, and a light output channel is provided in the second connecting part. The first installation cavity is connected to the light output channel. The laser emission source and the beam shaping element are installed in the first installation cavity, and the converging beam output by the laser emission source and the beam shaping element is output from the light output channel.

The second connection part 200 is also provided with a transition cavity, and the first installation cavity, the transition cavity and the light exit channel are connected in sequence. A reflector 310 is movably installed in the transition cavity, and the reflector 310 is connected to an actuator 330 fixedly installed inside the transition cavity. The actuator 330 is used to drive the reflector 310 to swing or vibrate in at least one dimensional direction. After the collimated light beam outputted from the laser emission source reaches the focusing mirror 140, it is focused by the focusing mirror 140 and transmitted to the reflector 310, and then reflected to the part to be processed to complete the processing of the workpiece. The welding gun adopts the above structure. Since the focusing mirror is integrated into the first connection part held by the hand during welding, the collimated light in the handheld welding gun can be converged before reaching the reflector, which is conducive to reducing the weight of the front end of the welding gun, making the staff more convenient and flexible when performing welding operations, and at the same time avoiding the situation where debris inside the gun barrel falls and causes damage to the focusing mirror.

Optionally, a beam splitter assembly (not shown in the figure) is fixedly installed in the transition cavity, and the beam splitter assembly includes a beam splitter 170 and an adjustment unit, the beam splitter 170 has a reflection surface and a transmission surface arranged oppositely, and the adjustment unit is used to adjust the reflectivity and transmittance of the beam splitter 170. Preferably, the reflectivity of the beam splitter to the incident light beam is 10% and the transmittance is 90%, so that a better preheating effect can be improved for the weld while achieving a higher welding efficiency.

Specifically, the beam splitter 170 is arranged upstream of the focusing mirror. The light beam converged by the focusing mirror 140 is divided into a preheating beam and a welding beam in proportion after passing through the beam splitter 170. The preheating beam is directly reflected by the beam splitter 170 and reaches the working area through the light output channel. The welding beam is transmitted from the beam splitter 170 to the reflector 310, and then reflected by the reflector 310 and reaches the weld in the working area through the light output channel.

In order to further achieve a better preheating effect, the angle between the beam splitter 170 and the optical axis of the original light beam is in the range of 50°-65°, and the light beam reflection assembly includes a reflector 310, and the angle between the reflector 310 and the optical axis of the original light beam is 55°. Under such an angle range, while achieving a higher welding efficiency, a better preheating effect can be achieved for the weld, the uniformity of the molten pool temperature is improved, and it is helpful to reduce the spatter generated during welding. In an embodiment of the present application, the preheating beam reaches the working area in advance after being reflected from the reflecting surface to achieve preheating of the weld.

It is understandable that the coverage area of the preheating spot formed by the preheating beam on the working area is much larger than the coverage area of the welding spot formed by the welding beam on the working area, which depends on the focal length of the optical lens in the beam shaping element and the working distance. In the actual design of the optical path, the preheating spot is sufficient to cover the complete weld on the working area to achieve uniform preheating at the first level.

In the embodiment of the present application, a spectroscopic component is used, and the preheating beam formed by the spectroscopic component provides primary preheating for the weld in the working area, and the welding beam provides secondary preheating and welding conditions for the weld in the working area, thereby greatly reducing the rapid evaporation and spattering caused by the concentration of heat energy during handheld welding, and achieving a high degree of stability of the molten pool.

Optionally, when the actuator 330 is configured as one, the reflector 310 can be directly driven to swing or vibrate in two-dimensional directions; when the actuator 330 is configured as two, the two actuators can respectively drive the reflector 310 to swing or vibrate in different directions. Preferably, the actuator 330 is a micro motor, and the micro motor is connected to the reflector 310 through the lens clamp 320.

It can be understood that the first installation cavity is arranged along the extension direction of the first connection part and is connected to the end of the first connection part. The laser emission source is fixedly installed at the rear end of the first installation cavity by fasteners such as bolts, and the focusing mirror 140 is located downstream of the laser emission source. By installing the focusing mirror originally arranged in the second connection part 200 in the first connection part, the weight of the second connection part 200 at the front end of the welding gun is effectively reduced, making the staff more convenient and flexible when performing welding operations, and reducing fatigue from long-term welding. Preferably, the first connection part and the second connection part 200 are directly connected and arranged at a preset angle to form a gun-shaped structure that is convenient for the staff to hold in their hands, so as to ensure that the staff maintains the best processing angle when holding the first connection part. Specifically, when using the laser welding gun, the staff holds the first connection part in their hands, aligns the output end of the second connection part 200 with the workpiece to be processed, turns on the power supply of the welding gun, and performs welding after determining various parameters.

In some embodiments, the laser emission source and the beam shaping element form a laser output head, which is directly inserted into the first mounting cavity from the end of the first connecting portion and is locked and sealed by an end cover.

In an embodiment of the present application, the first connecting part and the second connecting part 200 are detachably connected, and/or the transition cavity of the second connecting part 200 and the light output channel are detachably connected; a protective lens is provided between the first connecting part and the second connecting part 200, and between the transition cavity in the second connecting part and the light output channel.

In other embodiments, the first connection part and the second connection part 200 may also be integrally formed. The integrally formed laser welding device avoids problems such as seams and oxidation, which is beneficial to improving the performance and stability of the parts.

Since the focused beam energy outputted from the laser emission source and the beam shaping element is relatively high, the reflector 310 of the present application is provided with a preset anti-damage threshold to receive the convergent beam emitted from the focusing mirror 140 and reflect it to a preset position. Optionally, the reflective surface of the reflector 310 is coated with a dielectric film for strong lasers to effectively resist high-intensity laser beams and maintain its own performance from being damaged. Preferably, the reflectivity of the reflector 310 to the convergent beam reaches 99.9%.

It is understandable that in the embodiment of the present application, the collimated light beam is focused by the focusing mirror 140 before reaching the reflector 310, so the light beam energy received by the reflector 310 is relatively strong and generates relatively more heat. Therefore, the laser welding gun further includes a heat dissipation component (not shown in the figure), and the heat dissipation component is thermally connected to the reflector 310 to timely dissipate the heat of the reflector 310 to prevent it from being deformed by heat and affecting the welding effect.

Please continue to refer to Figure 6. The laser welding device of the present application also includes a first spacer ring 150 and a second spacer ring 160. The first spacer ring 150 is installed between the end cap 120 and the collimating lens 130, and the end cap 120 and the collimating lens 130 are respectively abutted against the two ends of the first spacer ring 150; the second spacer ring 160 is installed between the collimating lens 130 and the focusing lens 140, and the collimating lens 130 and the focusing lens 140 are respectively abutted against the two ends of the second spacer ring 160.

It is understandable that, in the technical solution of the present application, the first spacer 150 and the second spacer 160 have a step surface for fixing the lens inside to enhance the fixing effect and improve the assembly stability of the lens. Preferably, the contact surface between the second spacer 160 and the focusing lens 140 is an arc surface, which can make the second spacer 160 and the focusing lens 140 have a larger contact area, which is helpful for the heat dissipation of the focusing lens 140. Exemplarily, the second connecting part 200 includes a first part 201 and a second part 202 connected in sequence. The first part 201 is arranged close to the connection between the second connecting part 200 and the first connecting part, and the second part 202 includes a rod body and a nozzle connected thereto, and the second part 202 is connected to one end of the first part 201 through the connecting piece. Optionally, the second part 202 is quickly released and quickly locked relative to the first part 201 through the connecting piece to improve the disassembly and assembly efficiency of the welding gun during production or rework.

The protective mirror 210 is disposed in the second mounting cavity of the second connecting portion 200, and the reflector 310 is optically connected to the protective mirror 210. The protective mirror 210 is used to separate the external environment from the reflector 310, the focusing mirror 140 and the laser emission source inside the welding gun, thereby protecting the above optical components, specifically protecting each lens in the second connecting portion from dust, smoke, splashes and other pollution, and preventing the attenuation and scattering of the laser beam. The convergent light beam reflected from the reflector 310 passes through the protective mirror 210 and hits the workpiece to be processed for welding.

During the use of the device, the protective mirror 210 needs to be cleaned or replaced regularly to ensure the quality and stability of the laser beam. Therefore, optionally, the protective mirror 210 is configured as a drawer-type box structure and is detachably installed in the second installation cavity by elastic clips or fasteners so that it can be easily removed when replacing the protective mirror.

In summary, compared with the prior art, the present application provides a low-spatter laser welding method and device thereof. By using a laser welding method provided by the present application, the spot shape and energy distribution of the laser beam are changed after shaping. The weld on the working area is preheated and welded through different energy distribution areas, which can reduce the rapid evaporation and spatter caused by the concentration of heat energy during handheld welding, stabilize the molten pool, and reduce the generation of metal vapor. In the laser welding device of the present application, the beam shaping element (i.e., the collimator and the focusing lens/focusing lens) is arranged at the beam input end of the beam reflecting element, that is, the laser is shaped and converged before reflection. By arranging the focusing lens at the rear end of the welding device, it is helpful to prevent the splashes at the nozzle from flowing back and causing damage to the focusing lens. Therefore, the present application effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims (10)

1. A low spatter laser welding method, comprising: The laser beam is shaped to form a light spot with different energy distribution areas, and the different energy distribution areas of the light spot are used for preheating and welding respectively. 2 . The low-spatter laser welding method according to claim 1 , wherein the spot shape after shaping is different from the spot shape of the original laser beam. 3. The low-spatter laser welding method according to claim 2 is characterized in that the spot shape formed by the shaped laser beam is non-circular, and at least part of the energy gradually decreases along the processing direction. 4. The low-spatter laser welding method according to claim 3 is characterized in that the energy used for preheating of the light spot accounts for 2%-25% of the total energy of the light spot, and the energy used for welding accounts for 75%-98% of the total energy of the light spot. 5. The low-spatter laser welding method according to claim 1 is characterized in that laser beam shaping includes: using a collimator and a focusing lens to shape the divergent laser beam, the main optical axis of the collimator intersects with the central axis of the divergent light beam and is set at a preset angle, and the main optical axis of the focusing lens coincides with the central axis of the laser beam; or, the main optical axis of the collimator and the main optical axis of the focusing lens respectively intersect with the central axis of the divergent light beam and are set at a preset angle. 6. The low-spatter laser welding method according to claim 1 is characterized in that shaping the laser beam includes: using a focusing mirror to shape the collimated laser beam, and the main optical axis of the focusing mirror intersects with the central axis of the collimated beam and is set at a preset angle. 7. The low-spatter laser welding method according to claim 5 or 6, characterized in that the preset angle is in the range of 1.5°-4°. 8. The low-spatter laser welding method according to claim 5 or 6 is characterized in that the low-spatter laser welding method further comprises: using a splitting component to split the shaped laser beam, and after the splitting, a preheating beam and a welding beam are formed according to a predetermined ratio. 9. A laser welding device, characterized in that it is used to perform the laser welding method described in any one of claims 1 to 8, and the laser welding device comprises a laser emission source and a beam shaping element arranged in sequence along the light beam emission direction, wherein the laser emission source is used to emit a laser beam; and the beam shaping element is used to shape the laser beam to form a light spot with different energy distribution areas. 10. The laser welding device according to claim 9, characterized in that the laser welding device is used to weld materials with a plate thickness between 2 mm and 6 mm.