Adjustable composite spot laser processing head and processing method

Abstract

The application provides an adjustable composite light spot laser processing head and a processing method, and belongs to the technical field of laser processing. The adjustable composite light spot laser processing head comprises a light source, a light splitting cone lens, a collimating mirror and a focusing mirror. The light source, the light splitting cone lens, the collimating mirror and the focusing mirror are sequentially and spacedly arranged along the light beam direction of the light source. The light entrance surface of the light splitting cone lens comprises a conical refractive zone arranged around the optical axis and a planar transmission zone located at the optical axis and parallel to the light exit surface of the light splitting cone lens. The distance between the light splitting cone lens and the collimating mirror is adjustable. The point ring composite light spot can be stably generated, the power ratio can be adjusted, the laser energy loss can be avoided, and the laser welding processing efficiency can be improved.

Description

Technical Field

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

[0002] Point-and-ring composite laser welding technology is an advanced laser processing method that achieves precise control of the weld pool by shaping the laser beam into a central point spot and an annular spot surrounding it. During welding, the central point spot is responsible for deep penetration to form the weld depth, while the annular spot preheats or slowly cools the periphery of the weld pool. This effectively suppresses spatter, improves weld flowability, and reduces porosity, thus significantly improving weld quality and stability. Therefore, it is widely used in laser processing in demanding fields such as power batteries, electronic components, and precision parts.

[0003] Existing point-and-ring composite laser processing heads typically include: a composite light source or beam splitter module for generating point and ring beams; a central fiber and a ring fiber for transmitting the point and ring beams respectively; and an optical adjustment mechanism located inside the processing head. In the processing head, the central beam and ring beam are usually collimated separately by independent collimating lens groups, then coaxially combined by a beam combiner group, and finally focused onto the workpiece surface by a focusing lens group, forming a coaxial point-and-ring composite spot. To adapt to the requirements of different welding processes regarding spot size and energy distribution, some existing technologies incorporate variable magnification beam expanders or other adjustable optical modules in the optical path.

[0004] However, existing point-and-ring composite spot laser processing heads with the aforementioned structure have significant drawbacks in practical applications. When the power ratio of the final point and ring spots needs to be adjusted, it is usually necessary to add an independent zoom beam expander or module in the optical path for adjustment. Although this setup can achieve the function of adjusting the spot size and power ratio to a certain extent, it inevitably increases the number of optical components inside the processing head, resulting in a more complex overall structure and larger size, which is not conducive to flexible integration in confined spaces or automated production lines. More importantly, after the high-power laser beam formed by the light source passes through the multiple lens groups of the zoom beam expander or module, each mirror reflection or transmission will cause unavoidable energy loss. This accumulated energy loss not only reduces the utilization rate of laser energy, but may also exacerbate the thermal lensing effect of optical components, ultimately affecting the efficiency and long-term stability of laser welding processing. Summary of the Invention

[0005] This invention provides an adjustable composite spot laser processing head and method, which can stably generate a point-ring composite spot and adjust its power ratio while avoiding laser energy loss and improving laser welding efficiency. The technical solution is as follows: In a first aspect, embodiments of the present invention provide an adjustable composite spot laser processing head, comprising: a light source, a beam-splitting lens, a collimating lens, and a focusing lens. The light source, the beam-splitting conic lens, the collimating lens, and the focusing lens are arranged sequentially at intervals along the direction of the light beam emitted by the light source. The light-incident surface of the beam-splitting conic lens includes a conical refractive area arranged around the optical axis and a planar transmission area located at the optical axis and parallel to the light-outceasing surface of the beam-splitting conic lens. The distance between the beam-splitting conic lens and the collimating lens is adjustable. The light beam emitted by the light source partially illuminates the planar transmission area and is directly transmitted to form a point spot base beam. The other part illuminates the conical refraction area and is deflected after refraction to form an annular diverging beam with a larger divergence angle. The point spot base beam and the annular diverging beam are collimated by the collimating lens to form two parallel beams with a certain angle between them. After being focused by the focusing lens, a point spot located in the center and an annular spot surrounding the point spot are formed at the focal plane.

[0006] Optionally, the beam-splitting conic lens is connected to a displacement adjustment structure, which is configured to be drively connected to the beam-splitting conic lens to drive the beam-splitting conic lens to perform linear reciprocating motion relative to the collimating lens along the optical axis.

[0007] Optionally, the displacement adjustment structure includes a precision guide rail, a lead screw and nut pair, and a drive motor, wherein the drive motor drives the beam-splitting cone lens to move on the precision guide rail via the lead screw and nut pair.

[0008] Optionally, the displacement adjustment structure is connected to a grating ruler or a displacement sensor to detect the actual distance between the beam splitter lens and the collimating lens in real time and to form a closed-loop feedback control.

[0009] Optionally, the diameter of the planar transmission region ranges from 5 to 15 mm, and the diameter of the conical refraction region ranges from 30 to 37 mm.

[0010] Optionally, the axial cone angle of the conical surface of the conical refraction region ranges from 0.1 to 1 degree.

[0011] Optionally, the focal length of the collimating lens is 150mm.

[0012] Optionally, both the collimating lens and the focusing lens are plano-convex lenses or aspherical lenses.

[0013] In a second aspect, embodiments of the present invention provide a processing method based on the adjustable composite spot laser processing head described in the first aspect, comprising: A light beam is emitted from the light source. Part of the light beam illuminates the planar transmission area of ​​the beam-splitting conic lens and is directly transmitted to form a light spot base beam. After being shaped into a parallel beam by the collimating lens, it is focused on the workpiece surface by the focusing lens to form a point light spot. The beam is deflected by the conical refraction zone of the beam splitter lens to form a ring-shaped diverging beam. After being shaped into a parallel beam by the collimating lens, it is focused on the workpiece surface by the focusing lens to form a ring-shaped spot surrounding the point spot.

[0014] Optionally, the processing method further includes: adjusting the power ratio of the spot and the ring spot by changing the divergence characteristics of the base beam and the ring diverging beam through adjusting the distance between the beam splitter lens and the collimating lens.

[0015] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: By employing a beam-splitting conical lens with a planar transmission region and a conical refraction region, a single specially designed lens can be used to split a single laser beam into a point spot base beam and an annular diverging beam. Compared to existing technologies that require independent dual light sources or complex beam splitting and combining modules, the optical path system consists of only three lenses: a beam-splitting conical lens, a collimating lens, and a focusing lens. This greatly simplifies the system structure and reduces manufacturing costs. Simultaneously, the number of mirrors through which the beam passes is significantly reduced, minimizing energy loss during each mirror transmission and effectively improving laser energy utilization. This avoids the thermal lensing effect caused by an excessive number of optical components, thus ensuring the efficiency and long-term stability of laser welding. Furthermore, since the distance between the beam-splitting conical lens and the collimating lens is adjustable, the power ratio of the point spot and the annular spot can be continuously adjusted by controlling only the axial displacement in a single dimension. The control logic is simple, the response speed is fast, and it is suitable for the differentiated energy distribution requirements of different welding processes. Attached Figure Description

[0016] 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.

[0017] Figure 1 This is a schematic diagram of the adjustable composite spot laser processing head provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the light-incident surface of the beam-splitting conic lens provided in an embodiment of the present invention; Figure 3This is a schematic diagram of the light-emitting surface of the beam-splitting cone lens provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the displacement adjustment structure provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the adjustable composite spot laser processing head in the form of a straight head provided in an embodiment of the present invention; Figure 6 yes Figure 5 Structural cross-sectional view; Figure 7 This is a schematic diagram of the adjustable composite spot laser processing head in the form of a double-swing welding head provided in an embodiment of the present invention; Figure 8 yes Figure 7 Structural cross-sectional view; Figure 9 This is a schematic diagram of the adjustable composite spot laser processing head in the form of a galvanometer welding head provided in an embodiment of the present invention; Figure 10 yes Figure 9 Structural cross-sectional view; Figure 11 This is a flowchart of the processing method provided in the embodiments of the present invention.

[0018] In the picture: 1-Light source; 2-Beam splitter lens; 21-Conical refraction zone; 22-Planar transmission zone; 3-Collimating lens; 4-Focusing lens; 5-Displacement adjustment structure; 51-Precision guide rail; 52-Screw and nut pair; 53-Drive motor. Detailed Implementation

[0019] 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.

[0020] like Figures 1 to 10 As shown, an embodiment of the present invention provides an adjustable composite spot laser processing head, including: a light source 1, a beam splitter lens 2, a collimating lens 3, and a focusing lens 4.

[0021] In this optical system, the light source 1, beam-splitting lens 2, collimating lens 3, and focusing lens 4 are arranged sequentially and at intervals along the direction of the laser beam emitted by the light source 1. Specifically, the light source 1 is located at the very front of the entire optical path system and is used to emit the original diverging laser beam backward. In this embodiment, the light source 1 can be a fiber laser, a semiconductor laser, or other types of laser source, and the laser beam emitted by it has a certain divergence angle. The laser beam emitted by the light source 1 propagates along the optical axis and passes through the beam-splitting lens 2, collimating lens 3, and focusing lens 4 sequentially for optical shaping.

[0022] Specifically, the beam-splitting conic lens 2 is one of the core optical elements of this invention. Its incident surface includes two functional regions: a conical refractive region 21 arranged around the optical axis, and a planar transmission region 22 located at the optical axis and parallel to the exiting surface of the beam-splitting conic lens 2. The exiting surface of the beam-splitting conic lens 2 is entirely planar. The conical refractive region 21 has a positive conical shape and is arranged around the optical axis outside the planar transmission region 22. The planar transmission region 22 is located at the center of the incident surface of the beam-splitting conic lens 2, and its surface is parallel to the exiting surface. Therefore, the incident light does not refract in this region and maintains its original divergence characteristics for direct transmission. Through this structural design, the beam-splitting conic lens 2 can simultaneously split a laser beam emitted by the light source 1 into two beams with different properties, without the need for additional beam-splitting elements or multiple light source beam combining structures.

[0023] Furthermore, the distance between the beam-splitting conic lens 2 and the collimating lens 3 is adjustable. This adjustable distance is a key design feature for achieving the power ratio adjustment of the point spot and the ring spot. When the beam-splitting conic lens 2 moves relative to the collimating lens 3 along the optical axis, the divergence state of the two beams incident on the collimating lens 3 changes accordingly, thereby altering the power ratio of the point spot and the ring spot formed on the focal plane after collimation and focusing.

[0024] Specifically, when the light beam passes through the beam-splitting conical lens 2, a portion of the beam emitted from the light source 1 that illuminates the planar transmission region 22 is directly transmitted. Since the planar transmission region 22 is parallel to the light-emitting surface, this portion of the beam retains its original divergence characteristics, forming a spot-spot base beam. Simultaneously, another portion of the beam illuminating the conical refraction region 21 is deflected outwards due to the refraction of the conical surface, forming a ring-shaped diverging beam with a larger divergence angle. Because the conical refraction region 21 is symmetrical about the optical axis, the refracted beam is symmetrically distributed along the optical axis, exhibiting a ring-shaped divergence.

[0025] The aforementioned spot-shaped base beam and annular diverging beam are collimated by collimating lens 3 to form two parallel beams with a certain angle between them. The spot-shaped base beam, after collimation, becomes a parallel beam propagating along the optical axis; the annular diverging beam, after collimation, becomes a parallel beam with a certain angle to the optical axis. Both parallel beams pass through focusing lens 4 and are focused at its focal plane. The spot-shaped base beam is focused to form a central spot, and the annular diverging beam is focused to form an annular spot surrounding this spot. Both beams are coaxially distributed and together constitute a point-and-ring composite spot.

[0026] The technical solution of this embodiment, by employing a beam-splitting conical lens 2 with a planar transmission region 22 and a conical refraction region 21, achieves the function of splitting a single laser beam into a point spot base beam and an annular diverging beam using only a single specially made lens. Compared with the existing technology that requires independent dual light sources or complex beam splitting and combining modules, the optical path system consists of only three lenses: the beam-splitting conical lens 2, the collimating lens 3, and the focusing lens 4, greatly simplifying the system structure and reducing manufacturing costs. Simultaneously, the number of mirrors through which the beam passes along the optical path is significantly reduced, decreasing energy loss during each mirror transmission and effectively improving the utilization rate of laser energy. This avoids the thermal lensing effect caused by an excessive number of optical components, thereby ensuring the efficiency and long-term stability of laser welding processing. Furthermore, since the distance between the beam-splitting conical lens 2 and the collimating lens 3 is adjustable, the power ratio of the point spot and the annular spot can be continuously adjusted by controlling only the axial displacement in a single dimension. The control logic is simple, the response speed is fast, and it is suitable for the differentiated energy distribution requirements of different welding processes.

[0027] For example, refer to Figures 5 to 10 This invention provides various forms of adjustable composite spot laser processing head structures, corresponding to straight welding heads, double-swing welding heads, and galvanometer welding heads. All three incorporate the adjustable lens configuration provided in this invention within a conventional laser welding head to achieve continuous adjustment of the power ratio between the point spot and the annular spot. In other possible implementations, the lens configuration described in this solution can also be incorporated into more types of composite spot laser processing heads; this invention does not limit this approach.

[0028] Optionally, the beam splitter lens 2 is connected to a displacement adjustment structure 5, which is configured to be connected to the beam splitter lens 2 in a transmission manner to drive the beam splitter lens 2 to reciprocate linearly relative to the collimating lens 3 along the optical axis.

[0029] Specifically, in this embodiment, the displacement adjustment structure 5 and the beam-splitting conic lens 2 are linked by a mechanical transmission connection. The beam-splitting conic lens 2 is mounted on the movable part of the displacement adjustment structure 5. When the displacement adjustment structure 5 is working, it drives the beam-splitting conic lens 2 to perform precise linear displacement along the optical axis. Through this displacement adjustment structure 5, the beam-splitting conic lens 2 can move back and forth along the optical axis within a preset stroke range, thereby changing the axial distance between the beam-splitting conic lens 2 and the collimating lens 3.

[0030] When the beam-splitter lens 2 is close to the collimating lens 3, the diffusion range of the annular diverging beam upon reaching the collimating lens 3 is smaller. After collimation and focusing, the diameter of the resulting annular spot is smaller, and a larger proportion of the annular diverging beam is effectively received by the collimating lens 3. This results in a relatively larger power ratio of the final focused annular spot, and the energy within the annular spot is more concentrated. When the beam-splitter lens 2 is far from the collimating lens 3, the annular diverging beam has a longer propagation distance before reaching the collimating lens 3, increasing its incident height on the collimating lens 3. If this ring radius is too large, some beams may exceed the effective aperture of the collimating lens 3, causing some edge beams to be cut off. This reduces the proportion of energy in the annular diverging beam that can be effectively collimated and transmitted by the collimating lens 3. Consequently, the power ratio of the final focused annular spot decreases, while the power ratio of the spot increases. These adjustments alter the energy proportion of the annular beam that ultimately passes through the collimating lens 3 and enters the focusing lens 4. Meanwhile, since the base beam of the point spot transmitted through the planar transmission region 22 maintains its original divergence characteristics, the power of the point spot formed after passing through the collimating lens 3 and the focusing lens 4 remains basically stable under different axial spacings. Therefore, by adjusting the spacing between the beam splitter lens 2 and the collimating lens 3, the power ratio between the annular spot and the point spot can be effectively changed.

[0031] In this embodiment, by setting the displacement adjustment structure 5 and the beam splitter lens 2 for transmission connection, the power ratio adjustment process is made mechanized and controllable. Compared with the manual adjustment method, it has higher positioning accuracy and repeatability, and can meet the requirements of industrial laser processing for processing consistency.

[0032] Furthermore, the displacement adjustment structure 5 includes a precision guide rail 51, a lead screw and nut pair 52, and a drive motor 53. The precision guide rail 51 is arranged along the optical axis and is used to constrain and guide the movement direction of the beam splitter lens 2, ensuring that the beam splitter lens 2 always moves in a straight line along the optical axis during the movement process, without swaying or radial offset, so as to ensure the coaxiality of the optical path and the concentricity of the light spot.

[0033] The lead screw and nut assembly 52 is used to convert the rotational motion of the drive motor 53 into linear motion of the beam splitter lens 2 along the precision guide rail 51. The lead screw of the lead screw and nut assembly 52 is connected to the output shaft of the drive motor 53, and the nut is fixed to the mounting base of the beam splitter lens 2. When the drive motor 53 rotates forward or in reverse, the rotation of the lead screw drives the nut to move along the lead screw axis, thereby driving the beam splitter lens 2 to move forward or backward along the optical axis on the precision guide rail 51.

[0034] The drive motor 53 can be a stepper motor or a servo motor. When a stepper motor is used, the displacement of the beam splitter lens 2 can be precisely controlled by controlling the number and frequency of pulses; when a servo motor is used, higher precision closed-loop position control can be achieved through encoder feedback.

[0035] This embodiment constructs a compact and highly accurate displacement adjustment structure 5 by combining a precision guide rail 51, a lead screw and nut assembly 52, and a drive motor 53. This mechanism can achieve micron-level displacement accuracy control, meeting the requirements of laser processing for fine adjustment of the beam power ratio. Simultaneously, the lead screw and nut assembly 52 has a self-locking function; after the drive motor 53 stops operating, the beam splitter lens 2 can reliably remain in its current position, preventing displacement due to external interference such as vibration, thus ensuring the stability of the beam parameters during processing.

[0036] Furthermore, the displacement adjustment structure 5 is connected to a grating ruler or displacement sensor to detect the actual distance between the beam splitter lens 2 and the collimating lens 3 in real time, and to form a closed-loop feedback control.

[0037] Specifically, the grating ruler or displacement sensor is mounted on the side of the precision guide rail 51 or at a position fixed relative to the mounting base of the beam splitter lens 2, enabling real-time measurement of the axial displacement of the beam splitter lens 2 relative to the collimating mirror 3. The grating ruler has high-resolution position detection capability, typically reaching micrometer or even sub-micrometer resolution, accurately reflecting the actual position information of the beam splitter lens 2. The displacement sensor can be a linear encoder, a linear variable differential transformer (LVDT), or a magnetic grating ruler, etc.

[0038] The detected displacement signal is fed back to the control system, which compares the actual distance value with the target set value and controls the drive motor 53 to make corresponding compensation adjustments based on the deviation signal until the actual distance reaches the target set value. This closed-loop feedback control loop can eliminate position deviations caused by factors such as gap errors, thermal expansion deformation, and load changes that may exist during mechanical transmission, ensuring that the distance between the beam splitter lens 2 and the collimating lens 3 is always accurately controllable.

[0039] This embodiment achieves closed-loop feedback control by introducing a grating ruler or displacement sensor, which further improves the position control accuracy of the beam splitter lens 2 and enables it to maintain a stable beam power ratio output during long-term continuous processing, thus meeting the process requirements of high-precision laser processing.

[0040] Optionally, the diameter of the planar transmission region 22 ranges from 5 to 15 mm, and the diameter of the conical refraction region 21 ranges from 30 to 37 mm. Here, the diameter of the conical refraction region 21 refers to the outer diameter of the conical refraction region 21 on the incident surface of the beam-splitting lens 2.

[0041] Specifically, in this embodiment of the invention, the diameter of the planar transmission region 22 is set to 5 to 15 mm. This is significant because the diameter of the planar transmission region 22 determines the size of the beam cross-section that can be directly transmitted to form the base beam of the point spot. When the diameter of the planar transmission region 22 is small, the transmitted beam cross-section is small, and the power of the formed base beam of the point spot is relatively low. Correspondingly, more beams are incident on the conical refraction region 21 to form an annular diverging beam, and the power proportion of the annular spot is higher. When the diameter of the planar transmission region 22 is large, the opposite is true; the power proportion of the point spot increases. Therefore, selecting the diameter of the planar transmission region 22 within the range of 5 to 15 mm allows for the determination of a suitable basic power allocation ratio during the design phase, based on the actual laser processing requirements.

[0042] The diameter of the conical refractive region 21 is set to 30 to 37 mm. This size range matches the incident beam aperture of a conventional laser processing head, enabling it to effectively receive all or most of the laser beam emitted by the light source 1 and reduce edge beam loss. The proportional relationship between the diameters of the conical refractive region 21 and the planar transmission region 22 determines the initial energy distribution reference for the two beams.

[0043] In this embodiment, by reasonably setting the size parameters of the planar transmission area 22 and the conical refraction area 21, the basic power distribution range of the spot and the ring spot is determined in the design stage of the beam splitter lens 2. Combined with the adjustable spacing between the beam splitter lens 2 and the collimating lens 3, the power ratio can be continuously and finely adjusted within this basic range.

[0044] Optionally, the axial-cone angle of the conical refraction region 21 ranges from 0.1 to 1 degree. Exemplarily, in this embodiment of the invention, the axial-cone angle refers to the angle between the generatrix of the conical surface and the optical axis of the beam-splitting conic lens 2. The size of the axial-cone angle directly affects the divergence angle of the annular diverging beam after refraction by the conical surface. According to Snell's law of refraction, when the axial-cone angle is small, the deflection angle of the beam after refraction by the conical surface is small, the angle between the formed annular diverging beam and the optical axis is small, and the diameter of the annular spot formed after collimation and focusing is small, and the annular spot is closer to the center spot; when the axial-cone angle is large, the deflection angle of the beam increases, the diameter of the final annular spot is large, and the distance between the annular spot and the center spot increases.

[0045] Setting the axial cone angle within the range of 0.1 to 1 degree ensures that the refracted annular diverging beam remains within the effective aperture of collimating lens 3 when it propagates to it, preventing energy loss due to beam overflow caused by excessive deflection angle. It also ensures that the final annular spot has a suitable diameter, forming an effective spatial composite distribution with the center spot, meeting the spot size requirements of the point-ring composite laser welding process. Furthermore, within this angle range, adjusting the distance between the beam splitter lens 2 and the collimating lens 3 allows for relatively sensitive and continuous power ratio adjustment.

[0046] Optionally, in this embodiment of the invention, the focal length of the collimating lens 3 is 150mm. The selection of the focal length of the collimating lens 3 needs to take into account multiple factors: when the focal length is too short, the collimating lens 3 is highly sensitive to changes in the beam divergence angle, and even a small change in the axial spacing can lead to a significant change in the output beam parameters, requiring high adjustment precision and making control difficult; when the focal length is too long, although the adjustment stability is good, the overall length of the system increases accordingly, which is not conducive to the compact design of the laser processing head.

[0047] Setting the focal length of collimating lens 3 to 150mm provides sufficient travel space for adjusting the distance between the beam splitter lens 2 and collimating lens 3, while ensuring a reasonable overall system size. This allows for smooth and continuous adjustment of the power ratio of the spot and annular spots within the practically usable range. Simultaneously, the 150mm focal length, in conjunction with the axial cone angle range of the aforementioned conical refraction region 21, ensures that the collimated parallel beam has a suitable beam aperture and beam quality, providing favorable incident conditions for the subsequent focusing lens 4.

[0048] Optionally, both the collimating lens 3 and the focusing lens 4 are plano-convex lenses or aspherical lenses. In this embodiment of the invention, when the collimating lens 3 and the focusing lens 4 are plano-convex lenses, a plano-convex lens is a lens with one side being a plane and the other side being a spherical surface, which has the advantages of simple structure and low manufacturing cost. In use, the plane of the collimating lens 3 faces the side of the beam divergence, and the convex surface faces the side of the parallel beam. The mirror surface of the focusing lens 4 faces the opposite direction to that of the collimating lens 3, which can effectively reduce spherical aberration while ensuring basic optical performance and obtain a spot quality that meets general processing accuracy requirements.

[0049] When collimating lens 3 and focusing lens 4 are made of aspherical lenses, the surface curvature of the aspherical lens changes continuously in the radial direction, enabling more precise correction of various aberrations such as spherical aberration and coma. Using aspherical lenses results in higher focusing quality of the collimated and focused beam, higher energy concentration of the point spot, better uniformity of the annular spot, and higher concentricity between the point and annular spots. In applications requiring high welding quality and processing precision, aspherical lenses are the preferred choice.

[0050] In this embodiment, by selecting plano-convex or aspherical lenses as collimating lens 3 and focusing lens 4, aberrations are reduced while ensuring the quality of the focused spot. This allows the center spot to maintain the original beam quality, and the annular spot to have good uniformity, thereby improving the accuracy and consistency of laser processing.

[0051] Figure 11 This is a flowchart of the processing method provided in an embodiment of the present invention. For example... Figure 11 As shown, embodiments of the present invention also provide a processing method, based on... Figures 1 to 10 The adjustable composite spot laser processing head shown includes: S1. A light beam is emitted through the light source 1. Part of the light beam illuminates the planar transmission area 22 of the beam splitter lens 2 and is directly transmitted to form a light spot base beam. After being shaped into a parallel beam by the collimating lens 3, it is focused on the workpiece surface by the focusing lens 4 to form a point light spot.

[0052] Specifically, a light beam is emitted from the light source 1 and propagates along the optical axis to the beam-splitting conic lens 2. The portion of the light beam that illuminates the planar transmission area 22 of the beam-splitting conic lens 2 does not deflect the light beam because the planar transmission area 22 is parallel to the light-emitting surface. Therefore, this portion of the light beam is directly transmitted through the beam-splitting conic lens 2, maintaining its original divergence characteristics and forming a spot-spot base beam.

[0053] The spot beam continues to propagate along the optical axis to collimating lens 3, where it is refracted and shaped into a parallel beam. This parallel beam then propagates to focusing lens 4, where it is focused onto the workpiece surface at the focal plane of the focusing lens 4, forming a spot. Since the planar transmission zone 22 does not change the divergence angle of the original beam, the center spot formed after collimation and focusing maintains the beam quality of the original beam, exhibiting high power density and good focusing characteristics, making it suitable for deep penetration welding to achieve sufficient penetration depth.

[0054] S2. The cone-shaped refraction zone 21 of the beam splitter lens 2 is used to deflect another part of the beam to form a ring-shaped diverging beam. After being shaped into a parallel beam by the collimating lens 3, it is focused on the workpiece surface by the focusing lens 4 to form a ring-shaped beam surrounding the outside of the spot.

[0055] Specifically, another portion of the beam emitted from the light source 1, which illuminates the conical refraction region 21 of the beam-splitting conic lens 2, is deflected outward due to the refraction of the conical surface, forming a ring-shaped diverging beam with a larger divergence angle. Since the conical refraction region 21 is symmetrically arranged around the optical axis, the refracted beam is distributed in a ring-shaped symmetrical pattern in space.

[0056] After the annular diverging beam propagates to collimating lens 3, it is refracted by collimating lens 3 and shaped into a parallel beam with a certain angle to the optical axis. This parallel beam continues to propagate to focusing lens 4, where it is focused to form an annular spot surrounding the center spot on the workpiece surface. The diameter of the annular spot is larger than that of the center spot, and the two are coaxially distributed, together forming a point-ring composite spot. The annular spot can preheat or slowly cool the outer area of ​​the weld pool, effectively suppressing spatter, improving weld pool fluidity, and reducing porosity. Working synergistically with the center spot, it significantly improves welding quality and stability.

[0057] S3. By adjusting the distance between the beam splitter lens 2 and the collimating lens 3, the divergence characteristics of the base beam and the ring diverging beam are changed, thereby adjusting the power ratio of the spot and the ring beam.

[0058] Specifically, when the axial distance between the beam-splitting conic lens 2 and the collimating lens 3 is increased, the annular diverging beam expands over a longer propagation distance after refraction by the conic surface. This increases its incident height on the incident surface of the collimating lens 3, causing some edge beams in the annular diverging beam to exceed the effective aperture of the collimating lens 3 and be truncated. This reduces the energy of the annular beam ultimately participating in focusing, lowers the power proportion of the annular spot, and correspondingly increases the power proportion of the point spot. Conversely, when the axial distance between the beam-splitting conic lens 2 and the collimating lens 3 is decreased, the expansion of the annular diverging beam decreases, more of the annular beam can enter the effective aperture of the collimating lens 3, and the power proportion of the annular spot increases.

[0059] Furthermore, changes in the axial spacing also affect the parallelism of the annular beam after collimation and the diameter of the annular spot after focusing. By precisely controlling the spacing between the beam-splitting conic lens 2 and the collimating lens 3, the power and size of the annular spot can be adjusted simultaneously. In actual processing, operators or automatic control systems can precisely adjust this spacing through the displacement adjustment structure 5 according to different welding process requirements to obtain the optimal point-to-ring power ratio and spot size parameters, meeting the welding process requirements of different application scenarios such as power batteries, electronic components, and precision parts.

[0060] The processing method in this embodiment uses a beam-splitting conical lens 2 to simultaneously shape a single laser beam into a point-spot base beam and a ring-shaped diverging beam. After collimation and focusing, a coaxial point-ring composite spot is formed on the workpiece surface. The process steps are simple and efficient. Furthermore, the power ratio can be continuously adjusted by adjusting the distance between the beam-splitting conical lens 2 and the collimating lens 3. During the adjustment process, there is no need to replace optical components or change the light source parameters, making the operation convenient and able to quickly adapt to the switching needs of different welding conditions.

[0061] Unless otherwise defined, the technical or scientific terms used herein should be understood in their ordinary sense by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this 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 elements or objects preceding “comprising” or “including” encompass or are identical to the elements or objects listed following “comprising” or “including,” 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. The terms “upper,” “lower,” “left,” and “right” 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.

[0062] 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. An adjustable composite spot laser processing head, characterized in that, include: Light source (1), beam splitter lens (2), collimating lens (3) and focusing lens (4). The light source (1), the beam splitter lens (2), the collimating lens (3), and the focusing lens (4) are arranged sequentially at intervals along the direction of the light beam emitted by the light source (1). The light incident surface of the beam splitter lens (2) includes a conical refractive area (21) arranged around the optical axis and a planar transmission area (22) located at the optical axis and parallel to the light exit surface of the beam splitter lens (2). The distance between the beam splitter lens (2) and the collimating lens (3) is adjustable. The light beam emitted by the light source (1) partially illuminates the planar transmission area (22) and is directly transmitted to form a spot base beam. The other part illuminates the conical refraction area (21) and is deflected after refraction to form an annular diverging beam with a larger divergence angle. The spot base beam and the annular diverging beam are collimated by the collimating lens (3) to form two parallel beams with a certain angle between them. After being focused by the focusing lens (4), a spot located in the center and an annular spot surrounding the spot are formed at the focal plane.

2. The adjustable composite spot laser processing head according to claim 1, characterized in that, The beam splitter lens (2) is connected to a displacement adjustment structure (5), which is configured to be connected to the beam splitter lens (2) in a transmission manner to drive the beam splitter lens (2) to reciprocate linearly relative to the collimating lens (3) along the optical axis.

3. The adjustable composite spot laser processing head according to claim 2, characterized in that, The displacement adjustment structure (5) includes a precision guide rail (51), a lead screw and nut pair (52), and a drive motor (53). The drive motor (53) drives the beam splitter lens (2) to move on the precision guide rail (51) through the lead screw and nut pair (52).

4. The adjustable composite spot laser processing head according to claim 2, characterized in that, The displacement adjustment structure (5) is connected to a grating ruler or displacement sensor to detect the actual distance between the beam splitter lens (2) and the collimating lens (3) in real time and form a closed-loop feedback control.

5. The adjustable composite spot laser processing head according to claim 1, characterized in that, The diameter of the planar transmission region (22) ranges from 5 to 15 mm, and the diameter of the conical refractive region (21) ranges from 30 to 37 mm.

6. The adjustable composite spot laser processing head according to claim 5, characterized in that, The axial cone angle of the cone surface of the conical refraction region (21) ranges from 0.1 to 1 degree.

7. The adjustable composite spot laser processing head according to claim 6, characterized in that, The focal length of the collimating lens (3) is 150mm.

8. The adjustable composite spot laser processing head according to claim 1, characterized in that, Both the collimating lens (3) and the focusing lens (4) are plano-convex lenses or aspherical lenses.

9. A processing method, implemented based on the adjustable composite spot laser processing head as described in any one of claims 1 to 8, characterized in that, include: A light beam is emitted through the light source (1). Part of the light beam is irradiated by the planar transmission area (22) of the beam splitter lens (2) and then directly transmitted to form a light spot base beam. After being shaped into a parallel beam by the collimating lens (3), it is focused on the surface of the workpiece by the focusing lens (4) to form a point light spot. The beam is deflected by the cone-shaped refraction area (21) of the beam splitter lens (2) to form an annular diverging beam. After being shaped into a parallel beam by the collimating lens (3), it is focused on the workpiece surface by the focusing lens (4) to form an annular spot surrounding the spot.

10. The processing method according to claim 9, characterized in that, The processing method further includes: adjusting the distance between the beam splitter lens (2) and the collimating lens (3) to change the divergence characteristics of the spot base beam and the ring diverging beam, so as to adjust the power ratio of the spot and the ring beam.

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