Composite spot laser processing head and method

Abstract

The application provides a composite light spot laser processing head and a processing method, and belongs to the technical field of laser processing. The composite light spot laser processing head comprises a light source, a collimating mirror, a light splitting cone lens and a multi-curvature focusing mirror, wherein the light source, the collimating mirror, the light splitting cone lens and the multi-curvature focusing mirror are sequentially arranged along the light beam direction of the light source, the center of the light splitting cone lens is provided with a center hole, the light entrance surface of the multi-curvature focusing mirror is an outer convex aspheric arc surface, the aspheric arc surface comprises a first mirror surface area and a second mirror surface area which are sequentially arranged from the inside to the outside in the radial direction, and the mirror surface curvature of the first mirror surface area is smaller than that of the second mirror surface area. The composite light spot laser processing head can stably generate a point-ring composite light spot, reduce the structural complexity and manufacturing cost, realize the miniaturization of the structure and the improvement of the scene use adaptability.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and in particular to a composite spot laser processing head and processing method. Background Technology

[0002] In the field of laser material processing, especially in demanding welding applications, the point-ring composite spot technology has attracted much attention due to its ability to significantly improve the stability of the welding process and the quality of the weld. This technology combines a central spot with one or more surrounding ring spots, working together on the workpiece. The central spot, with its high energy density, is primarily responsible for deep penetration welding, forming a deep and narrow molten pool; while the outer ring spots, with their more uniform energy distribution, mainly serve to preheat, slow cool, or stabilize the keyhole of the molten pool, effectively suppressing spatter, eliminating porosity, and improving weld formation. This synergistic effect gives point-ring composite spot lasers significant advantages when welding aluminum alloys, highly reflective materials, and dissimilar metals.

[0003] In existing technologies, laser processing heads that achieve point-ring composite light spots typically employ a discrete design for their core optical path structure. Specifically, the point and ring light spots are generated through independent optical paths and ultimately coupled to the same output mirror group. For example, two independent fiber lasers are used as the point source and ring source, respectively, and their output beams are coupled through a spatial combiner or a fiber combiner.

[0004] However, the existing discrete optical path structures described above have significant limitations. When processing requirements upgrade from a single-ring spot to a dual-ring or even multi-ring composite spot, the usual solution in existing technologies is to introduce more independent laser sources or to set up a more complex beam splitting and combining system, such as using multiple diffractive optical elements cascaded together. This approach directly leads to a surge in the number of system components and extremely complex optical path debugging, resulting in a large overall size and high manufacturing cost for the laser processing head, thus limiting the widespread application of point-ring composite spot technology in advanced manufacturing scenarios that require flexible adjustment of spot modes and power ratios. Summary of the Invention

[0005] This invention provides a composite spot laser processing head and method, which can stably generate point-ring composite spots while reducing structural complexity and manufacturing costs, achieving miniaturization and improved adaptability to various application scenarios. The technical solution is as follows:

[0006] In a first aspect, embodiments of the present invention provide a composite spot laser processing head, comprising: a light source, a collimating lens, a beam-splitting conic lens, and a multi-curvature focusing lens.

[0007] The light source, the collimating lens, the beam splitter lens, and the multi-curvature focusing lens are arranged sequentially along the direction of the light beam emitted by the light source. The beam splitter lens has a central hole at its center. The light incident surface of the multi-curvature focusing lens is an outwardly convex aspherical arc surface. The aspherical arc surface includes a first mirror area and a second mirror area arranged radially from the inside to the outside. The mirror curvature of the first mirror area is less than the mirror curvature of the second mirror area.

[0008] The light beam emitted by the light source is shaped into a parallel beam by the collimating lens. Part of the beam is focused to form a point spot after passing through the central hole of the beam splitter lens and the multi-curvature focusing lens. Another part of the beam is shaped into a ring beam by the beam splitter lens and illuminates the first and second mirror areas on the multi-curvature focusing lens. The multi-curvature focusing lens then focuses the light beam to form an inner ring spot and an outer ring spot surrounding the point spot.

[0009] Optionally, the beam-splitting conical lens is detachably installed inside the composite spot laser processing head, and multiple beam-splitting conical lenses are provided, each with a different central hole diameter.

[0010] Optionally, it also includes a variable magnification beam expander module disposed between the collimating lens and the beam splitter lens, comprising a first positive lens, a negative lens and a second positive lens arranged sequentially along the beam direction emitted by the light source, wherein the distance between the negative lens and the second positive lens is adjustable.

[0011] Optionally, the variable magnification beam expander module further includes an adjustment slide rail arranged along the beam direction emitted by the light source, and both the negative lens and the second positive lens are slidably mounted on the adjustment slide rail.

[0012] Optionally, the collimating lens is a variable focus collimating lens.

[0013] Optionally, it also includes a power control unit for controlling the output power of the light source.

[0014] In a second aspect, embodiments of the present invention provide a processing method, implemented based on the composite spot laser processing head described in the first aspect, comprising:

[0015] The light beam emitted by the light source is shaped into a parallel beam by the collimating lens. A portion of the light beam is transmitted through the central hole of the beam splitter lens and focused on the workpiece surface by the multi-curvature focusing lens to form a spot.

[0016] The beam splitter lens shapes another portion of the light beam into a ring beam and illuminates the first and second mirror areas on the multi-curvature focusing mirror. The multi-curvature focusing mirror focuses the light beam illuminating the first mirror area onto the workpiece surface to form an inner ring spot surrounding the spot. The multi-curvature focusing mirror also focuses the light beam illuminating the second mirror area onto the workpiece surface to form an outer ring spot surrounding the inner ring spot.

[0017] Optionally, the beam-splitting conic lens is configured to be detachably mounted inside the composite spot laser processing head, and the processing method further includes:

[0018] By replacing the beam-splitter lens with a central aperture of a different diameter, the energy ratio of the central beam used to focus and form the point spot and the annular beam used to form the inner and outer annular spots can be adjusted.

[0019] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0020] The adjustable composite spot laser processing head provided in this invention employs a compact structure combining a single light source with a beam-splitting conical lens and a multi-curvature focusing mirror. After beam splitting by the perforated beam-splitting conical lens, the different curvatures of the first and second mirror areas of the multi-curvature focusing mirror enable the invention to stably generate point spots, inner ring spots, and outer ring spots from a single light source. Compared to single-ring composite spots, double-ring composite spots can better control the temperature distribution and flow state of the molten pool, further improving welding quality and stability. Compared to existing technologies that require two or more independent laser sources to generate point spots and ring spots separately, the optical path structure of this invention is simpler, smaller, easier to integrate and maintain, achieving structural miniaturization while improving adaptability to various application scenarios. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the optical path structure of a composite spot laser processing head provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the light-emitting surface side of the beam-splitting conic lens provided in an embodiment of the present invention;

[0024] Figure 3This is a schematic diagram of the light-incident surface of the multi-curvature focusing lens provided in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the light-emitting surface side of the multi-curvature focusing lens provided in an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the internal structure of the variable magnification beam expander module provided in an embodiment of the present invention;

[0027] Figure 6 This is a block diagram of the control structure of the power control unit provided in an embodiment of the present invention;

[0028] Figure 7 This is a schematic diagram of the optical path structure of another composite spot laser processing head provided in an embodiment of the present invention;

[0029] Figure 8 This is a flowchart of the processing method provided in the embodiments of the present invention.

[0030] In the picture:

[0031] 1-Light source; 2-Collimating lens; 3-Beam splitter lens; 4-Multi-curvature focusing lens; 5-Variable magnification beam expander module; 6-Power control unit; 7-Plan-concave lens; 8-Plan-convex lens; 31-Center hole; 41-First mirror area; 42-Second mirror area; 51-First positive lens; 52-Negative lens; 53-Second positive lens; 54-Adjusting slide rail. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0033] Figure 1 This is a schematic diagram of the optical path structure of a composite spot laser processing head provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the light-emitting surface side of the beam-splitting conic lens provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the light-incident surface of the multi-curvature focusing lens provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the light-emitting surface side of the multi-curvature focusing lens provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the internal structure of the variable magnification beam expander module provided in an embodiment of the present invention; Figure 6 This is a block diagram of the control structure of the power control unit provided in an embodiment of the present invention. Figures 1 to 6 As shown, this embodiment of the invention provides a composite spot laser processing head, comprising: a light source 1, a collimating lens 2, a beam splitter lens 3, and a multi-curvature focusing lens 4.

[0034] In this configuration, the light source 1, collimating lens 2, beam-splitting conic lens 3, and multi-curvature focusing lens 4 are arranged sequentially along the beam direction emitted by the light source 1. The beam-splitting conic lens 3 has a central hole 31 at its center. The light-incident surface of the multi-curvature focusing lens 4 is an outwardly convex aspherical arc surface. The aspherical arc surface includes a first mirror area 41 and a second mirror area 42 arranged radially from the inside out. The mirror curvature of the first mirror area 41 is smaller than that of the second mirror area 42.

[0035] After the light beam emitted by the light source 1 is shaped into a parallel beam by the collimating lens 2, part of the beam passes through the central hole 31 of the beam splitter lens 3 and the multi-curvature focusing lens 4 and is focused to form a point spot. The other part of the beam is shaped into a ring beam by the beam splitter lens 3 and illuminates the first mirror area 41 and the second mirror area 42 on the multi-curvature focusing lens 4. The multi-curvature focusing lens 4 focuses the beam to form an inner ring spot and an outer ring spot around the outside of the point spot.

[0036] In this embodiment of the invention, the light source 1, collimating lens 2, beam splitter lens 3, and multi-curvature focusing lens 4 are arranged sequentially on the same optical axis along the beam direction emitted by the light source 1, forming a complete optical path transmission chain. The beam splitter lens 3 has a central hole 31 at its center. This central hole 31 is a circular through-hole, and its diameter is designed according to the energy distribution ratio between the required center point spot power and the ring spot power. The multi-curvature focusing lens 4 is one of the core optical elements of this invention, and its incident surface is a convex aspherical arc surface. This aspherical arc surface includes a first mirror area 41 and a second mirror area 42 arranged radially from the inside out. The first mirror area 41 and the second mirror area 42 transition continuously in the radial direction, but have different curvature characteristics: the mirror curvature of the first mirror area 41 is smaller than that of the second mirror area 42. Specifically, the first mirror area 41 is located in the central region of the multi-curvature focusing lens 4, and its radius of curvature is relatively large, and its surface is relatively flat, used to refract and focus the inner ring beam from the beam splitter lens 3. The second mirror region 42 is located outside the first mirror region 41. Its radius of curvature is relatively small, and the mirror surface is more curved, providing stronger refractive power for refracting and focusing the outer ring beam from the beam splitter lens 3.

[0037] The working principle of this invention is based on the principle of beam splitting and zone focusing, and the specific working process is as follows:

[0038] Collimation stage: The initial beam emitted by light source 1 first passes through collimating lens 2. Collimating lens 2 collimates and shapes the incident beam, converting divergent or converging beams into parallel beams. After being shaped by collimating lens 2, the beam diameter remains constant, and the light rays are parallel to each other, creating ideal incident conditions for subsequent beam splitting and focusing.

[0039] Beam splitting stage: The collimated parallel beam is incident on the beam-splitting conic lens 3. Because the beam-splitting conic lens 3 has a central aperture 31, the beam is split into two parts here:

[0040] Part 1: The portion of the beam located at the center of the beam, whose incident position is exactly aligned with the central aperture 31, is unaffected by the conical surface of the beam-splitting lens 3 and continues to propagate directly through the central aperture 31 in a parallel state, forming the central point beam. The energy of this central point beam is determined by the diameter of the central aperture 31.

[0041] The second part: The beam in the annular region surrounding the main beam has its incident position on the conical surface of the beam-splitting lens 3. This part of the beam is shaped into an annular beam by refraction through the conical surface. Specifically, the conical surface causes the incident parallel light to diverge outward at different angles, forming one or more annular light cones with different cone angles. Based on the geometry of the conical surface, these annular beams can be further divided into inner and outer ring beams, corresponding to different refraction angles.

[0042] Focusing Stage: The beam split by the beam-splitting conic lens 3 continues to propagate to the multi-curvature focusing mirror 4. The multi-curvature focusing mirror 4 performs segmented focusing based on the different characteristics of the incident beam:

[0043] For the center point beam: This beam is incident on the central region of the multi-curvature focusing mirror 4 while remaining parallel to the light source. The central region of the multi-curvature focusing mirror 4 converges the beam, focusing it onto the focal plane of the workpiece surface to form a high-energy-density spot. This spot is used to achieve deep penetration welding, forming a deep and narrow weld pool, ensuring weld depth and quality.

[0044] For the ring beam: the beam is incident at different cone angles onto the first mirror region 41 and the second mirror region 42 of the multi-curvature focusing mirror 4. Because the first mirror region 41 has a smaller mirror curvature, it provides moderate refractive force to the inner ring beam, focusing it onto the focal plane of the workpiece surface, forming an inner ring spot surrounding the outer edge of the spot. Because the second mirror region 42 has a larger mirror curvature, it provides stronger refractive force to the outer ring beam, focusing it onto the focal plane of the workpiece surface, forming an outer ring spot surrounding the outer edge of the inner ring spot.

[0045] Figure 7 This is a schematic diagram of the optical path structure of another composite spot laser processing head provided in an embodiment of the present invention, for reference. Figure 7 In another possible implementation, an additional set of lenses can be added in conjunction with the multi-curvature focusing lens 4 to form a variable focal length focusing lens group during the focusing phase. For example, a set of lenses can be placed behind the multi-curvature focusing lens 4, such as... Figure 7The plano-concave lens 7 and plano-convex lens 8, with focal lengths ranging from 100 to 150 mm, are coaxially arranged with the multi-curvature focusing mirror 4. A through-hole for the center point beam is also provided in the center of the plano-concave lens 7 and plano-convex lens 8. During adjustment, moving the positive lens group closer to the multi-curvature focusing mirror 4 shifts the focal plane where the inner and outer ring beams converge relative to the point beam forward; moving the positive lens group further away from the multi-curvature focusing mirror 4 shifts the focal plane where the inner and outer ring beams converge relative to the point beam backward. This typically allows for a linear displacement adjustment range of 20-50 mm. This structural configuration allows for adaptation to different processing positions through rear-end fine-tuning.

[0046] Through the above-described beam splitting and zone focusing design, this invention achieves a composite beam structure on the workpiece surface consisting of a central point beam, an inner ring beam, and an outer ring beam. The three beams act simultaneously on the same plane of the workpiece surface, ensuring the synergy and stability of the processing.

[0047] In actual processing, the workflow of this invention is as follows:

[0048] Light source 1 is activated to emit a laser beam. The power of the laser beam is set according to the processing requirements. The laser beam is then shaped into a parallel beam by collimating lens 2. The focal length and lens parameters of collimating lens 2 are selected based on the divergence angle of the laser beam and the required collimated beam diameter. The parallel beam then enters beam-splitting conical lens 3. The central portion of the beam passes through the central aperture 31, maintaining its parallel propagation state; the outer portion of the beam is refracted by the conical surface of beam-splitting conical lens 3, shaping it into a ring beam. The central beam and the ring beam then continue propagating to multi-curvature focusing lens 4. The central beam enters the central region of multi-curvature focusing lens 4 and is focused to form a point spot; the ring beam enters the first mirror area 41 and the second mirror area 42 respectively, and is focused to form an inner ring spot and an outer ring spot. Finally, the combined spot acts on the workpiece surface for laser processing. The spot spot provides high energy density, enabling deep penetration welding; the inner and outer ring spots provide preheating and stabilize the molten pool, suppressing spatter and porosity, and improving weld formation.

[0049] The adjustable composite spot laser processing head provided in this embodiment of the invention employs a compact structure consisting of a single light source 1, a beam-splitting conical lens 3, and a multi-curvature focusing mirror 4. After beam splitting by the perforated beam-splitting conical lens 3, the multi-curvature focusing mirror 4 utilizes the different curvature designs of its first mirror area 41 and second mirror area 42 to stably generate point spots, inner ring spots, and outer ring spots using a single light source. Compared to single-ring composite spots, double-ring composite spots can better control the temperature distribution and flow state of the molten pool, further improving welding quality and stability. Compared to existing technologies that require two or more independent laser sources to generate point spots and ring spots separately, the optical path structure of this invention is simpler, smaller, easier to integrate and maintain, achieving structural miniaturization while improving adaptability to various application scenarios.

[0050] Optionally, the beam-splitting conical lens 3 is detachably mounted inside the composite spot laser processing head. Multiple beam-splitting conical lenses 3 are provided, each with a different diameter of its central aperture 31. Exemplarily, in this embodiment of the invention, by replacing beam-splitting conical lenses 3 with different central aperture 31 diameters, the energy ratio between the central point beam and the annular beam can be flexibly adjusted. For example, when increasing the welding depth is required, a larger diameter central aperture 31 can be selected, concentrating more energy on the point spot; when enhancing the stability of the molten pool is required, a smaller diameter central aperture 31 can be selected, distributing more energy to the annular spot. This design provides flexible adaptability to different process requirements.

[0051] Specifically, the beam-splitting conic lens 3 can be installed inside the housing of the processing head via a quick-release mechanism. This quick-release mechanism can employ snap-fit, threaded, or magnetic connections to ensure that the beam-splitting conic lens 3 can be installed and removed quickly and stably, while maintaining optical axis alignment accuracy.

[0052] Optionally, the system also includes a variable magnification beam expander module 5 disposed between the collimating lens 2 and the beam splitter lens 3. This module includes a first positive lens 51, a negative lens 52, and a second positive lens 53 arranged sequentially along the beam direction emitted from the light source 1. The distance between the negative lens 52 and the second positive lens 53 is adjustable. The first positive lens 51 receives the parallel beam output from the collimating lens 2 and initially contracts it. The focal length of the first positive lens 51 is selected based on the diameter of the collimated beam and the required contraction ratio, and is typically a positive focal length lens. The negative lens 52, located after the first positive lens 51, diverges the beam contracted by the first positive lens 51. The focal length of the negative lens 52 is negative, and its divergence angle determines the degree of beam expansion of subsequent beams. The second positive lens 53, located after the negative lens 52, refocuses the diverged beam from the negative lens 52 into parallel light for emission. The focal length of the second positive lens 53 is selected based on the divergence angle of the negative lens 52 and the required diameter of the emitted beam. The distance between the negative lens 52 and the second positive lens 53 is adjustable. By adjusting the distance between the negative lens 52 and the second positive lens 53, the diameter of the emitted parallel beam can be changed, thereby achieving the variable magnification beam expansion function. When the distance increases, the diverging beam has a longer propagation distance before reaching the second positive lens 53, resulting in a larger beam diameter and a larger diameter of the parallel beam converged by the second positive lens 53; conversely, when the distance decreases, the diameter of the emitted parallel beam also decreases. The emitted parallel beam continues to propagate to the beam-splitting conic lens 3 and the multi-curvature focusing lens 4, forming a composite spot according to the aforementioned working principle. Because the variable magnification beam expansion module 5 changes the beam diameter incident on the beam-splitting conic lens 3, the size of the final composite spot also changes accordingly. Specifically, when the emitted beam diameter increases, the diameter of the beam at the center point through the central aperture 31 increases, resulting in a larger point spot size; simultaneously, the radial dimension of the annular beam refracted by the beam-splitting conic lens 3 also increases, resulting in larger inner and outer ring spots.

[0053] By adjusting the magnification of the variable magnification beam expander module 5, the size of the composite beam spot can be continuously adjusted. This allows a single processing head to adapt to various processing scales, from precision welding to large-area cladding, greatly improving the versatility and flexibility of the equipment. With a fixed output power of the light source 1, changing the beam spot size alters the power density acting on the workpiece surface. A smaller beam spot size results in a higher power density, suitable for deep-penetration welding and precision machining; a larger beam spot size results in a lower power density, suitable for surface cladding and large-area processing. The variable magnification beam expander module 5 provides coarse adjustment capabilities for the total power density and size of the entire composite beam spot system, while fine adjustment of the energy distribution ratio can be achieved by replacing the beam splitter lens 3 with different central hole diameters 31. The combination of these two features provides users with multi-dimensional adjustment capabilities to meet complex and varied processing requirements.

[0054] Optionally, the variable magnification beam expander module 5 further includes an adjustment slide rail 54 arranged along the beam direction emitted by the light source 1, on which the negative lens 52 and the second positive lens 53 are slidably mounted. Exemplarily, in this embodiment, the adjustment slide rail 54 is a precision guide rail structure arranged along the beam propagation direction. The negative lens 52 and the second positive lens 53 are respectively mounted on the adjustment slide rail 54 via sliding seats, allowing them to slide freely along the guide rail direction. A low-friction coefficient material or a ball bearing guide structure is used between the sliding seats and the guide rail to ensure smooth and precise sliding. In one possible implementation, the adjustment slide rail 54 is equipped with a scale and a locking mechanism. The scale indicates the position coordinates of the negative lens 52 and the second positive lens 53, facilitating precise adjustment and repeated positioning by the operator. The locking mechanism is used to fix the lens position after adjustment, preventing positional displacement due to vibration or external force during processing. In manual adjustment mode, the operator can move the negative lens 52 and the second positive lens 53 along the adjustment slide rail 54 by rotating the adjustment handwheel or pushing the sliding seat. By observing the position coordinates on the scale, the distance between the two lenses can be precisely controlled, thereby accurately adjusting the beam magnification.

[0055] In another possible implementation, the adjusting slide rail 54 is equipped with an electric adjusting mechanism. This electric adjusting mechanism includes a stepper motor or servo motor, a transmission mechanism such as a lead screw, rack and pinion, and a control system. The operator can input the desired beam expansion ratio or spot size through the control system, and the electric adjusting mechanism automatically calculates and drives the negative lens 52 and the second positive lens 53 to the corresponding positions, achieving automated adjustment. In automatic adjustment mode, the operator inputs the desired beam expansion ratio or spot size through the control system. The control system calculates the position coordinates of the negative lens 52 and the second positive lens 53 according to a preset optical calculation model, and then drives the electric adjusting mechanism to move the two lenses to the target positions. The entire process is completed automatically without manual intervention, greatly improving adjustment efficiency and accuracy.

[0056] Optionally, the collimating lens 2 is a variable-focus collimating lens. For example, in this embodiment of the invention, by setting a variable-focus collimating lens, the divergence angle of the light source 1 can be compensated. Regardless of whether the light source 1 uses a laser diode or fiber optic output, adjustments are made according to changes in the light source characteristics, thereby outputting a high-quality parallel beam. This ensures that the beam is in the optimal input state during the subsequent processes of the variable-magnification beam expander module 5 and beam splitting to form a point ring spot, thus being compatible with diverse light source forms and processing requirements.

[0057] Optionally, a power control unit 6 is also included, which controls the output power of the light source 1. Exemplarily, in this embodiment of the invention, the power control unit 6 controls the output power of the light source 1. The power control unit 6 is electrically connected to the light source 1 and can monitor and adjust the operating parameters of the light source 1 in real time, such as injection current, pump power, or output laser power, thereby achieving precise control of the output laser power. In one possible implementation, the power control unit 6 includes a power sensor, a controller, and a drive circuit. The power sensor monitors the output power of the light source 1 in real time; the controller calculates the required control signal based on the feedback signal from the power sensor and the target power set by the user; the drive circuit adjusts the operating parameters of the light source 1 according to the control signal to achieve the target output power. By combining the power control unit 6 with the variable magnification beam expander function, the user can adjust the power density from two dimensions: power and spot size. This provides great flexibility, adapting to the processing needs of different materials, thicknesses, and processes.

[0058] Figure 8 This is a flowchart of the processing method provided in an embodiment of the present invention. For example... Figure 8 As shown, embodiments of the present invention also provide a processing method, based on... Figures 1 to 7 The composite spot laser processing head shown includes:

[0059] S1. A light beam is emitted from the light source 1, and after being shaped into a parallel beam by the collimating lens 2, part of the light beam is transmitted through the central hole 31 of the beam splitter lens 3, and then focused on the workpiece surface by the multi-curvature focusing lens 4 to form a spot.

[0060] S2. Using the beam splitter lens 3, another part of the beam is shaped into a ring beam and irradiated onto the first mirror area 41 and the second mirror area 42 on the multi-curvature focusing mirror 4. The beam irradiated onto the first mirror area 41 is focused on the workpiece surface by the multi-curvature focusing mirror 4 to form an inner ring spot surrounding the outside of the spot. The beam irradiated onto the second mirror area 42 is focused on the workpiece surface by the multi-curvature focusing mirror 4 to form an outer ring spot surrounding the outside of the inner ring spot.

[0061] Optionally, the beam-splitting conic lens 3 is configured to be detachably mounted inside the composite spot laser processing head, and the processing method further includes:

[0062] S3. By replacing the beam splitter lens 3 with a center hole 31 of different diameters, the energy ratio of the center beam used to focus and form the point spot and the ring beam used to form the inner ring spot and the outer ring spot can be adjusted.

[0063] Using the composite spot laser processing head provided in this embodiment of the invention, and performing laser welding through the above-described processing method, the composite spot structure can simultaneously achieve deep penetration welding and molten pool stability, effectively suppressing defects such as spatter, porosity, and cracks during the welding process, thus improving the quality and reliability of the weld. The synergistic effect of the composite spot improves welding speed and stability, reduces defects and rework rates, and increases production efficiency and product qualification rate. By replacing the beam splitter lens 3 with different central hole diameters 31, the energy distribution ratio can be flexibly adjusted to adapt to the processing needs of different materials such as aluminum alloys, stainless steel, and titanium alloys, different thicknesses such as thin plates and thick plates, and different processes such as welding, cladding, and quenching.

[0064] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the element or object preceding “comprising” or “including” encompasses all elements or objects listed following “comprising” or “including” and are identical to them, but do not exclude other elements or objects. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. “Up,” “down,” “left,” “right,” etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0065] The above description is merely an optional embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A composite spot laser processing head, characterized in that, include: Light source (1), collimating lens (2), beam splitter lens (3) and multi-curvature focusing lens (4). The light source (1), the collimating lens (2), the beam splitter lens (3), and the multi-curvature focusing lens (4) are arranged sequentially along the beam direction emitted by the light source (1). The beam splitter lens (3) has a central hole (31) at its center. The light incident surface of the multi-curvature focusing lens (4) is an outwardly convex aspherical arc surface. The aspherical arc surface includes a first mirror area (41) and a second mirror area (42) arranged radially from the inside to the outside. The mirror curvature of the first mirror area (41) is smaller than that of the second mirror area (42). The light beam emitted by the light source (1) is shaped into a parallel beam by the collimating lens (2). Part of the beam passes through the central hole (31) of the beam splitter lens (3) and the multi-curvature focusing lens (4) and is focused to form a point spot. Another part of the beam is shaped into a ring beam by the beam splitter lens (3) and illuminates the first mirror area (41) and the second mirror area (42) on the multi-curvature focusing lens (4). The multi-curvature focusing lens (4) focuses the beam to form an inner ring spot and an outer ring spot around the outside of the point spot.

2. The composite spot laser processing head according to claim 1, characterized in that, The beam splitter lens (3) is detachably installed inside the composite spot laser processing head. Multiple beam splitter lenses (3) are provided, and the diameter of the central hole (31) of the multiple beam splitter lenses (3) is different.

3. The composite spot laser processing head according to claim 1, characterized in that, It also includes a variable magnification beam expander module (5) disposed between the collimating lens (2) and the beam splitter lens (3), comprising a first positive lens (51), a negative lens (52) and a second positive lens (53) arranged sequentially along the beam direction emitted by the light source (1), wherein the distance between the negative lens (52) and the second positive lens (53) is adjustable.

4. The composite spot laser processing head according to claim 3, characterized in that, The variable magnification beam expander module (5) also includes an adjustment slide rail (54) arranged along the beam direction emitted by the light source (1), and the negative lens (52) and the second positive lens (53) are slidably mounted on the adjustment slide rail (54).

5. The composite spot laser processing head according to claim 1, characterized in that, The collimating lens (2) is a variable focus collimating lens.

6. The composite spot laser processing head according to claim 1, characterized in that, It also includes a power control unit (6) for controlling the output power of the light source (1).

7. A processing method, implemented based on the composite spot laser processing head as described in any one of claims 1 to 6, characterized in that, include: The light beam emitted by the light source (1) is shaped into a parallel beam by the collimating lens (2), and then part of the light beam is transmitted through the central hole (31) of the beam splitter lens (3), and then focused on the workpiece surface by the multi-curvature focusing lens (4) to form a spot. The beam splitter lens (3) is used to shape another part of the beam into a ring beam and irradiate the first mirror area (41) and the second mirror area (42) on the multi-curvature focusing lens (4). The multi-curvature focusing lens (4) focuses the beam irradiating the first mirror area (41) on the workpiece surface to form an inner ring spot surrounding the outside of the spot. The multi-curvature focusing lens (4) focuses the beam irradiating the second mirror area (42) on the workpiece surface to form an outer ring spot surrounding the outside of the inner ring spot.

8. The processing method according to claim 7, characterized in that, The beam-splitting conic lens (3) is configured to be detachably installed inside the composite spot laser processing head, and the processing method further includes: By replacing the beam splitter lens (3) with a central hole (31) of a different diameter, the energy ratio of the central beam used to focus and form the point spot and the annular beam used to form the inner and outer annular spots can be adjusted.

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