Laser engraving machine and control method

Abstract

The invention relates to the technical field of desktop laser engraving, and provides a laser engraving machine and a control method. The laser engraving machine comprises a light source assembly, a dynamic zooming assembly, a light reflection assembly and a field lens, the dynamic zooming assembly and the light reflection assembly are sequentially arranged on a propagation path of emergent light of the light source assembly, and the field lens is arranged on a propagation path of emergent light of the light reflection assembly; the light source assembly is used for emitting light beams to the dynamic zooming assembly. The light reflection assembly is used for reflecting the light beam passing through the dynamic zooming assembly to the field lens; the field lens is used for focusing the light beam to enable the focus of the light beam to act on a to-be-processed surface; the dynamic zooming assembly is used for adjusting the acting position of the focus of the light beam.

Description

Technical Field

[0001] This application relates to the field of desktop laser engraving technology, and more particularly to laser engraving machines and control methods. Background Technology

[0002] Laser engraving machines, as high-precision, non-contact processing equipment, have been widely used in industrial manufacturing, cultural and creative industries, and personalized customization. A typical desktop galvanometer-type laser engraving machine usually includes core components such as a laser source, a scanning galvanometer (as a light reflection component 3), and an F-theta field lens 4. During operation, the laser beam is deflected by the galvanometer and then focused by the field lens 4, forming a high-energy-density focal point on the workpiece surface, thereby achieving engraving or cutting.

[0003] However, such devices in the prior art generally suffer from a fundamental limitation: their focal plane is fixed. To accommodate machining surfaces of varying heights or three-dimensional curved workpieces, traditional solutions typically employ one of the following two methods: Firstly, the workpiece is moved as a whole using a mechanical lifting platform; Secondly, the entire laser head (including the light source, galvanometer, and field lens 4) is driven to move along the Z-axis to adjust the focal length.

[0004] The above method has obvious drawbacks: First, mechanical movement has a large moment of inertia and a slow response speed, making it difficult to meet the requirements of high-speed, high-precision dynamic focusing. Secondly, frequent machine movements can easily introduce vibration and positioning errors, affecting processing quality; Furthermore, for complex free-form surfaces (such as spheres and irregular curved surfaces), the fixed focal plane cannot keep the focus in constant contact with the workpiece surface throughout the entire processing area, resulting in severe defocusing at the edge areas, deterioration of the processing effect, or even failure to form the shape. Finally, due to the limited depth of field of field lens 4, the effective processing area is strictly limited, which further restricts the application range of the equipment.

[0005] In addition, although some high-end devices have attempted to introduce motorized zoom lenses or acousto-optic focusing elements, these solutions are often costly, complex in structure, and difficult to be compatible with multi-wavelength lasers (such as blue light and infrared light), which is not conducive to their widespread adoption in desktop devices.

[0006] Therefore, there is an urgent need for a new type of laser engraving machine structure that can quickly, accurately, and dynamically adjust the position of the laser focus without moving the entire machine or workpiece, thereby achieving high-quality and high-efficiency processing of any three-dimensional curved or stepped surface. Summary of the Invention

[0007] This application aims to address at least one of the technical problems existing in the related art.

[0008] A laser engraving machine according to a first aspect of this application includes a light source assembly, a dynamic zoom assembly, a light reflection assembly, and a field lens. The dynamic zoom assembly and the light reflection assembly are sequentially disposed on the propagation path of the emitted light from the light source assembly, and the field lens is disposed on the propagation path of the emitted light from the light reflection assembly. The light source assembly is used to emit a light beam to the dynamic zoom assembly; The light reflection component is used to reflect the light beam that has passed through the dynamic zoom component to the field lens; The field lens is used to focus the light beam so that the focal point of the beam acts on the surface to be processed; The dynamic zoom component is used to adjust the focal point of the light beam.

[0009] According to one embodiment of this application, the dynamic zoom component includes a moving element, a first concave lens, a first convex lens, and a second convex lens. The first concave lens, the first convex lens, and the second convex lens are sequentially disposed on the propagation path of the emitted light of the light source component, and the light reflection component is located on the propagation path of the emitted light of the second convex lens. The movable component is connected to the first concave lens, and the movable component is used to move the first concave lens relative to the first convex lens to change the distance between the first concave lens and the second convex lens.

[0010] According to one embodiment of this application, the light source assembly includes a first light source, a second light source, a first light adjustment assembly, a second light adjustment assembly, and a beam combiner. The first light source and the first light adjustment component are arranged opposite to each other. The first light adjustment component is used to expand and collimate the emitted light from the first light source and transmit the resulting first beam to the beam combiner. The second light source and the second light adjustment component are arranged opposite to each other. The second light adjustment component is used to expand and collimate the emitted light from the second light source and transmit the resulting second beam to the beam combiner. The beam combiner is located between the light source assembly and the dynamic zoom assembly. The beam combiner is used to combine the first beam and the second beam and transmit the resulting mixed beam to the dynamic zoom assembly.

[0011] According to one embodiment of this application, the light source assembly further includes a reflector, the first light adjustment assembly is located between the first light source and the reflector, the first light adjustment assembly is used to expand and collimate the emitted light from the first light source and transmit the resulting first beam to the reflector, and the reflector is used to reflect the first beam to the beam combiner.

[0012] According to one embodiment of this application, the first light adjustment component includes a second concave lens and a third convex lens, wherein the second concave lens is located between the first light source and the third convex lens, and the third convex lens is located between the second concave lens and the reflector.

[0013] According to one embodiment of this application, the second light adjustment component includes a third concave lens and a fourth convex lens, wherein the third concave lens is located between the fourth convex lens and the second light source, and the fourth convex lens is located between the reflector and the third concave lens.

[0014] According to one embodiment of this application, the light reflecting component includes a first galvanometer and a second galvanometer that are parallel to each other; The first galvanometer is located on the propagation path of the emitted light from the dynamic zoom component. The first galvanometer is used to reflect the light beam passing through the dynamic zoom component to the second galvanometer, and the second galvanometer is used to reflect the light beam to the field lens.

[0015] According to one embodiment of this application, the laser engraving machine further includes a fixed base plate, a depth camera, and a control module. The depth camera and the field lens are mounted on the same side of the fixed base plate. The control module is connected to the fixed base plate. The depth camera is electrically connected to the control module. The depth camera is used to acquire three-dimensional image data of the object to be processed. The control module is configured to: determine control parameters based on the three-dimensional image data acquired by the depth camera; and control the operation of the dynamic zoom component according to the control parameters.

[0016] The control method for a laser engraving machine as described above, according to a second aspect embodiment of this application, includes: Acquire 3D image data of the object to be processed; Based on the three-dimensional image data, the target focus position is determined; Based on the target focal position, the operation of the dynamic zoom component is controlled so that the focal point of the laser engraving machine's beam acts on the target focal position.

[0017] According to one embodiment of this application, the dynamic zoom component includes a first concave lens, a first convex lens, and a second convex lens. The first concave lens, the first convex lens, and the second convex lens are sequentially disposed on the propagation path of the emitted light of the light source component, and the light reflection component is located on the propagation path of the emitted light of the second convex lens. The step of controlling the operation of the dynamic zoom component based on the target focus position includes: Based on the target focal position, determine the target movement distance of the first concave lens; Based on the target moving distance, control the movement of the first concave lens.

[0018] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a simplified structural diagram of the laser engraving machine provided in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the laser engraving machine provided in the embodiments of this application; Figure 3 This is a partial structural schematic diagram of the laser engraving machine provided in the embodiments of this application. Detailed Implementation

[0021] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but should not be used to limit the scope of this application.

[0022] In the description of the embodiments of this application, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0024] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0025] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0026] The following is combined with Figures 1 to 3 This application describes the laser engraving machine and its control method.

[0027] According to the embodiments of the first aspect of this application, such as Figure 1 As shown, the laser engraving machine includes a light source assembly 1, a dynamic zoom assembly 2, a light reflection assembly 3, and a field lens 4. The dynamic zoom assembly 2 and the light reflection assembly 3 are sequentially arranged on the propagation path of the emitted light from the light source assembly 1, and the field lens 4 is arranged on the propagation path of the emitted light from the light reflection assembly 3. Light source assembly 1 is used to emit a light beam to dynamic zoom assembly 2; The light reflection component 3 is used to reflect the light beam that has passed through the dynamic zoom component 2 to the field lens 4; Field lens 4 is used to focus the light beam so that the focal point of the beam acts on the surface to be processed; The dynamic zoom component 2 is used to adjust the focal point of the light beam.

[0028] During operation, the laser beam emitted by the light source assembly 1 is first incident on the dynamic zoom assembly 2. The dynamic zoom assembly 2 uses its internal adjustable optical elements (such as an axially movable lens group) to change the wavefront curvature or divergence angle of the beam in real time, thereby controlling the focusing depth of the beam after transmission through the subsequent optical path. The beam modulated by the dynamic zoom assembly 2 enters the light reflection assembly 3 (such as a two-dimensional scanning galvanometer), which deflects it at high speed in the horizontal plane to control the XY coordinates of the light spot. Finally, the beam is focused onto the surface to be processed by the field lens 4. Since the dynamic zoom assembly 2 can independently and quickly adjust the position of the focal point along the Z-axis without moving the light source assembly 1, the light reflection assembly 3, or the workpiece, the system can ensure that the focal point always accurately matches the actual contour of the material, even when facing a workpiece surface with a complex three-dimensional shape, thus achieving high-precision processing throughout the entire process.

[0029] Compared to related technologies that rely on mechanical lifting platforms or overall laser head movement to adjust the focal length, this application fundamentally eliminates the response delay, vibration interference, and cumulative positioning errors caused by large-inertia mechanical motion by integrating a dynamic zoom component 2 into the optical path. At the same time, the dynamic focus control capability breaks through the physical limitations of traditional fixed focal planes, effectively solving the processing degradation problem caused by defocusing in the edge areas of complex free-form surfaces (such as spheres and irregular curved surfaces). In addition, by compensating for the optical path difference at different scanning positions in real time, the effective depth of field and usable processing area are significantly expanded. This structure does not require expensive acousto-optic focusing devices and is compatible with multi-wavelength laser sources, balancing high performance with the cost controllability of desktop equipment, thereby achieving high-quality, high-efficiency, and highly adaptable laser processing of any three-dimensional curved or stepped surface.

[0030] In some examples, the dynamic zoom component 2 includes a zoom lens group consisting of a movable concave lens driven by a drive motor and a fixed convex lens; the light source component 1 can output 450nm blue light and 1064nm infrared light, and achieve coaxial confocal output through the beam combiner 15; the light reflection component 3 is a high-speed MEMS galvanometer or an electromagnetically driven scanning galvanometer; the field lens 4 is an F-theta flat field lens; the control system is based on the three-dimensional point cloud data acquired by the depth camera 6, and calculates and synchronously controls the movement of the dynamic zoom component 2 and the galvanometer in real time; this structure is suitable for marking electronic components, precision mold engraving, personalized customization of handicrafts and consumer-grade 3D curved surface laser processing equipment.

[0031] In one embodiment of this application, such as Figure 1 and Figure 3 As shown, the dynamic zoom component 2 includes a moving part 21, a first concave lens 22, a first convex lens 23, and a second convex lens 24. The first concave lens 22, the first convex lens 23, and the second convex lens 24 are sequentially arranged on the propagation path of the emitted light of the light source component 1, and the light reflection component 3 is located on the propagation path of the emitted light of the second convex lens 24. The movable component 21 is connected to the first concave lens 22. The movable component 21 is used to drive the first concave lens 22 to move relative to the first convex lens 23, so as to change the distance between the first concave lens 22 and the second convex lens 24.

[0032] Understandably, the collimated beam from the light source assembly 1 first passes through the first concave lens 22, and then sequentially through the first convex lens 23 and the second convex lens 24. The first concave lens 22, acting as a dynamic focusing element, is driven by a moving component 21 (such as a miniature linear motor or lead screw drive mechanism), allowing for precise displacement relative to the fixedly mounted first convex lens 23 and second convex lens 24 along the optical axis. As the first concave lens 22 moves, the optical distance between it and the second convex lens 24 changes, thereby adjusting the equivalent focal length of the entire zoom assembly and the divergence characteristics of the output beam. This change, transmitted through the subsequent light reflection assembly 3 and field lens 4, ultimately manifests as a shift in the focal point's position along the normal direction (Z-axis) of the surface to be processed. By controlling the stroke of the moving component 21, the focal depth can be adjusted continuously and in real time without moving the entire machine or the workpiece.

[0033] This design utilizes the principle of nonlinear optical levers to effectively amplify the minute displacement of the first concave lens 22 into a significant focal point movement, achieving both high sensitivity and a large focusing range. Simultaneously, the first convex lens 23 and the second convex lens 24 form a stable conjugate imaging system. The second convex lens 24 is preferably a cemented doublet achromatic lens, which effectively corrects focal separation caused by dispersion in lasers of different wavelengths (such as blue and infrared light), ensuring multi-path laser confocal output. Thus, without increasing system complexity, high-precision dynamic focusing on three-dimensional curved surfaces is achieved, solving problems such as defocusing, edge blurring, and limited area in curved surface processing caused by slow mechanical focusing response and low precision in related technologies.

[0034] In some examples, the moving component 21 is a piezoelectric ceramic driver or a stepper motor with a precision guide rail, and the displacement resolution can reach the micrometer level; the first concave lens 22 is a negative power lens, and the first convex lens 23 and the second convex lens 24 are both positive power lenses, which together form a Galilean zoom structure; the second convex lens 24 adopts a double-cemented design to eliminate chromatic aberration and ensure that the focal points of 450nm blue light and 1064nm infrared light coincide; this dynamic zoom component 2 is integrated into a compact optical path module and is suitable for desktop multi-material compatible 3D laser engraving equipment.

[0035] In one embodiment of this application, such as Figure 1 and Figure 3 As shown, the light source assembly 1 includes a first light source 11, a second light source 12, a first light adjustment assembly 13, a second light adjustment assembly 14, and a beam combiner 15; The first light source 11 and the first light adjustment component 13 are arranged opposite to each other. The first light adjustment component 13 is used to expand and collimate the emitted light from the first light source 11 and transmit the resulting first beam to the beam combiner 15. The second light source 12 and the second light adjustment component 14 are arranged opposite to each other. The second light adjustment component 14 is used to expand and collimate the emitted light from the second light source 12 and transmit the resulting second beam to the beam combiner 15. The beam combiner 15 is located between the light source assembly 1 and the dynamic zoom assembly 2. The beam combiner 15 is used to combine the first beam and the second beam and transmit the resulting mixed beam to the dynamic zoom assembly 2.

[0036] Understandably, the beam emitted by the first light source 11 (such as a 450nm blue laser) is expanded and collimated by the first light adjustment component 13 (usually a Galilean beam expander system composed of concave and convex lenses) to form a first beam with good parallelism. Simultaneously, the beam emitted by the second light source 12 (such as a 1064nm infrared pulsed laser) undergoes similar processing by the second light adjustment component 14 to form a second beam. The two collimated beams are incident on the beam combiner 15 from different directions: one side of the beam combiner 15 highly reflects the first wavelength light (such as blue light), while the other side highly transmits the second wavelength light (such as infrared light), thus coaxially combining the two beams into a single collinear propagating mixed beam, which is then guided into the downstream dynamic zoom component 2. This mixed beam is subsequently focused by dynamic zoom, galvanometer scanning, and field lens 4 to form a switchable or synergistic processing focus on the workpiece surface.

[0037] By integrating dual-wavelength light sources and employing a beam combiner 15 to achieve coaxial output, this application significantly expands the material adaptability of laser engraving machines. For example, blue light is suitable for the fine processing of highly reflective metals (such as copper and gold) and transparent materials, while infrared light excels at the efficient etching of non-metallic materials such as plastics, wood, and ceramics. More importantly, since the two beams are spatially overlapped before entering the dynamic zoom assembly 2, and the second convex lens 24 in the dynamic zoom assembly 2 adopts an achromatic design, it can effectively suppress the focus shift caused by the difference in refractive index of different wavelengths of light, ensuring that the two lasers remain confocal at any focusing position, thereby avoiding ghosting or energy dispersion problems during multi-wavelength processing. This solution achieves integrated high-precision 3D engraving capabilities for multiple materials and processes without increasing mechanical complexity.

[0038] In some examples, the first light source 11 is a 450±10nm semiconductor blue laser, and the second light source 12 is a 1064nm fiber pulsed laser; both the first light adjustment component 13 and the second light adjustment component 14 are two-piece beam expander collimating lens assemblies; the beam combiner 15 is a dielectric film beam splitter with a reflectivity ≥98% for 450nm light and a transmittance ≥95% for 1064nm light; the optical axis consistency error of the mixed beam is less than 0.1 mrad; this dual-light source structure, combined with a dynamic zoom module, is widely used in scenarios such as electronic component marking, jewelry micro-carving, composite material cutting, and personalized consumer product customization.

[0039] In one embodiment of this application, such as Figure 1 and Figure 3 As shown, the light source assembly 1 also includes a reflector 16. The first light adjustment assembly 13 is located between the first light source 11 and the reflector 16. The first light adjustment assembly 13 is used to expand and collimate the emitted light from the first light source 11 and transmit the resulting first beam to the reflector 16. The reflector 16 is used to reflect the first beam to the beam combiner 15.

[0040] Understandably, the original beam emitted by the first light source 11 (such as a 450nm blue laser) is first processed by the first light adjustment component 13 (usually a beam expander and collimator system composed of concave and convex lenses) to form a first beam with high parallelism and a small divergence angle. This beam is then incident on the reflector 16, which reflects it at a specific angle (usually 90°) and guides it to the beam combiner 15. At the same time, the second beam from the second light source 12, processed by the second light adjustment component 14, is directly incident on the beam combiner 15. Through the introduction of the reflector 16, the propagation path of the first beam is deflected, allowing the two light sources to be spatially staggered, effectively avoiding physical interference between the two optical paths in the initial stage, while also optimizing the compactness of the overall internal layout. After being deflected by the reflector 16, the first beam and the second beam are coaxially combined at the beam combiner 15 to form a single mixed beam that enters the dynamic zoom component 2.

[0041] This design, through the rational planning of the optical path of the first beam using reflector 16, achieves efficient integration of a dual-light source system within a limited device volume. This not only reduces the risk of assembly interference between optical components but also facilitates the separate debugging and maintenance of each light source channel. More importantly, the introduction of reflector 16 does not alter the collimation characteristics of the first beam, ensuring that it maintains good coaxiality and wavefront consistency with the second beam after beam combining. This provides stable input conditions for the subsequent multi-wavelength confocal control of the dynamic zoom component 2. Thus, without sacrificing beam quality, the manufacturability and space utilization of the overall structure are improved.

[0042] In some examples, the reflector 16 is a high-reflectivity dielectric film plane mirror with a reflectivity of ≥99% for a wavelength of 450nm; the reflector 16 is mounted on a mirror mount that can be finely adjusted for pitch and yaw, for precise calibration of the incident angle of the first beam; the optical path length between the first light adjustment component 13 and the reflector 16 is optimized according to the overall system size, and is usually controlled within the range of 30–80 mm; this layout is widely used in desktop multi-wavelength laser engraving equipment, and is especially suitable for consumer-grade or small industrial models with high requirements for internal space compactness.

[0043] In one embodiment of this application, such as Figure 1 and Figure 3 As shown, the first light adjustment assembly 13 includes a second concave lens 131 and a third convex lens 132. The second concave lens 131 is located between the first light source 11 and the third convex lens 132, and the third convex lens 132 is located between the second concave lens 131 and the reflector 16.

[0044] Understandably, the diverging beam emitted by the first light source 11 (such as a 450nm blue laser) first enters the second concave lens 131, where its negative optical power initially expands the beam. Subsequently, the expanded beam enters the third convex lens 132, where its positive optical power collimates the beam, ultimately outputting a collimated first beam with high parallelism and a diameter suitable for the subsequent optical path, which is then transmitted to the reflector 16. The second concave lens 131 and the third convex lens 132 constitute a typical Galilean beam-expanding system, with their combined focal length and spacing precisely designed to match the original divergence angle of the first light source 11 and the spatial constraints of the overall optical path. After this adjustment, the first beam not only meets the beam quality requirements for beam combining and dynamic zooming but also effectively suppresses edge aberrations, ensuring good wavefront consistency during long-distance transmission.

[0045] The two-piece beam expander structure, consisting of a second concave lens 131 and a third convex lens 132, offers advantages over single-lens or complex multi-piece systems, including simple structure, low cost, high transmittance, and ease of assembly. Furthermore, the Galilean design eliminates the internal solid focal point, avoiding the risk of air ionization or optical component damage at the focal point due to high-power lasers, thus improving system reliability under high energy density conditions. In addition, the beam expansion ratio can be independently optimized based on the characteristics of different wavelength light sources, allowing for the configuration of appropriate light adjustment components for each of the two laser beams (such as blue light and infrared light). This ensures the coaxiality and focusing performance of the mixed beam after beam combining, laying the foundation for precise multi-wavelength confocal control of the subsequent dynamic zoom component 2.

[0046] In some examples, the focal length ratio of the second concave lens 131 to the third convex lens 132 is 1:3 to 1:5 to achieve a beam expansion ratio of 3–5 times; the two lenses are coaxially mounted in a metal lens barrel, and the spacing is adjusted by precision shims or threads; the lens surface is coated with an anti-reflection coating for the 450nm band, with a single-sided reflectivity of less than 0.2%; this light adjustment component is integrated into a compact light source module and is suitable for desktop multi-material laser engraving equipment with high requirements for beam quality and system stability.

[0047] In one embodiment of this application, such as Figure 1 and Figure 3 As shown, the second light adjustment assembly 14 includes a third concave lens 141 and a fourth convex lens 142. The third concave lens 141 is located between the fourth convex lens 142 and the second light source 12, and the fourth convex lens 142 is located between the reflector 16 and the third concave lens 141.

[0048] Understandably, the diverging beam emitted by the second light source 12 (such as a 1064nm infrared pulsed laser) first undergoes preliminary beam expansion through the third concave lens 141, and then enters the fourth convex lens 142 for collimation, ultimately forming a second beam with good parallelism and diameter matching system requirements, which is then directly transmitted to the beam combiner 15. The third concave lens 141 and the fourth convex lens 142 also constitute a Galilean beam expansion and collimation system. Their optical parameters (such as focal length and spacing) are specifically optimized according to the wavelength characteristics (such as 1064nm) and beam divergence angle of the second light source 12 to ensure that the output beam has low divergence and high collimation characteristics, in order to meet the requirements of efficient beam combining with the first beam and subsequent dynamic zoom control. Since this optical path does not pass through the reflector 16 for deflection, the position of the fourth convex lens 142 is set on the side closer to the beam combiner 15, and located between the third concave lens 141 and the reflector 16, thus forming a spatially symmetrical or staggered arrangement with the first light adjustment component 13 in the overall layout, avoiding cross-interference between the two beam paths.

[0049] This two-piece beam expander structure not only simplifies the assembly complexity of the second optical adjustment component 14 but also effectively improves the light energy utilization rate. The Galilean design, without an internal solid focal point, prevents energy loss or beam distortion caused by air breakdown or thermal lensing effects during the transmission of high-power infrared lasers. Simultaneously, the optimized lens coating and material selection (such as fused silica) for the 1064nm band further ensure beam quality and the long-term stability of the system. More importantly, by independently configuring a beam expander and collimator system matching its wavelength for the second light source 12, it ensures that the second beam and the first beam guided by the reflector 16 have similar beam diameters and wavefront curvatures when combined, providing a crucial prerequisite for achieving high-precision coaxial beam combining and multi-wavelength confocal focusing.

[0050] In some examples, the combined beam expansion ratio of the third concave lens 141 and the fourth convex lens 142 is 2.5–4.5 times, which is adapted to the output characteristics of typical fiber lasers; the two lenses are mounted in temperature-controlled or shockproof brackets to suppress the influence of thermal drift on alignment accuracy; the lens surface is coated with a broadband antireflection film for the 1064nm band, with a single-sided reflectivity of less than 0.15%; the second light adjustment component 14 works in conjunction with the first light adjustment component 13 to jointly support the high compatibility and high processing consistency of dual-wavelength lasers in dynamic zoom engraving systems, and is suitable for multiple application scenarios such as metal marking, plastic micro-carving and precision cutting of composite materials.

[0051] In one embodiment of this application, such as Figure 1 and Figure 3 As shown, the light reflecting component 3 includes a first galvanometer 31 and a second galvanometer 32 that are parallel to each other; The first galvanometer 31 is located on the propagation path of the emitted light from the dynamic zoom assembly 2. The first galvanometer 31 is used to reflect the light beam that has passed through the dynamic zoom assembly 2 to the second galvanometer 32, and the second galvanometer 32 is used to reflect the light beam to the field mirror 4.

[0052] Understandably, the mixed beam modulated by the dynamic zoom component 2 first enters the first galvanometer 31, which deflects around its rotation axis to control the scanning angle of the beam in the first direction (e.g., the X-axis). The reflected beam then enters the second galvanometer 32, which is arranged strictly parallel to the first galvanometer 31. The second galvanometer 32 deflects around its orthogonal rotation axis to further control the scanning angle of the beam in the second direction (e.g., the Y-axis). Finally, the beam is reflected by the second galvanometer 32 into the field mirror 4 and focused on the surface to be processed. The parallel arrangement of the two galvanometers ensures that the optical path is stable and the deflection angle superposition relationship is clear during the two reflections, thereby achieving high-precision two-dimensional planar scanning. At the same time, since the dynamic zoom component 2 has pre-adjusted the focal depth (Z-axis), the galvanometer system only needs to focus on high-speed positioning in the XY plane. The functions of the two are decoupled, significantly improving the response speed and coordination accuracy of the overall machine control.

[0053] This parallel configuration of dual galvanometers effectively avoids beam drift, focus eccentricity, or scanning distortion problems that may be caused by non-parallel installation, ensuring the consistency of spot position and energy distribution across the entire processing area. Especially when used with the dynamic zoom assembly 2 to process three-dimensional curved surfaces, the stable optical path structure ensures that even with real-time changes in focal depth, the XY scanning coordinates can still accurately map to the actual contour of the workpiece surface, preventing image distortion. Furthermore, the parallel arrangement simplifies the optical path calibration process, improves assembly efficiency and long-term operational reliability, and provides a solid optical scanning foundation for high-speed, high-precision 3D laser engraving.

[0054] In some examples, the first galvanometer 31 and the second galvanometer 32 are both high-speed electromagnetically driven scanning galvanometers with a response frequency of 5–10 kHz. The 16 surfaces of the mirrors of the two galvanometers are coated with a wide-band high-reflectivity film, with a reflectivity of ≥98% for both 450nm blue light and 1064nm infrared light. The galvanometer mounting base is made of a low thermal expansion alloy material and integrates a position feedback sensor to achieve closed-loop control. This parallel dual-galvanometer structure is widely used in desktop and industrial-grade dynamic focusing laser processing equipment and is suitable for high-requirement scenarios such as electronic marking, precision micro-engraving, and engraving of complex curved surface patterns.

[0055] In one embodiment of this application, such as Figure 2 and Figure 3 As shown, the laser engraving machine also includes a fixed base plate 5, a depth camera 6, and a control module. The depth camera 6 and the field lens 4 are mounted on the same side of the fixed base plate 5. The control module is connected to the fixed base plate 5. The depth camera 6 is electrically connected to the control module. The depth camera 6 is used to acquire three-dimensional image data of the object to be processed. The control module is configured to: determine control parameters based on the three-dimensional image data acquired by the depth camera 6; and control the operation of the dynamic zoom component 2 according to the control parameters.

[0056] Understandably, the fixed base plate 5 serves as the core support platform for the entire machine, with the field lens 4 and depth camera 6 mounted on the same side to ensure a stable relative position and shared field of view. During operation, the depth camera 6 (such as a binocular stereo vision camera or a structured light sensor) performs non-contact scanning of the object to be processed, acquiring its surface 3D point cloud data in real time. After receiving this data, the control module reconstructs the 3D curved surface model of the workpiece using a built-in algorithm, maps the preset 2D engraving graphic onto the curved surface, and then calculates the Z-axis height information corresponding to each processing point. Based on this height information, the control module generates corresponding control parameters (such as the target displacement ΔS of the dynamic lens) and outputs a drive signal to the actuator of the dynamic zoom component 2, causing it to synchronously adjust the focus position during laser scanning to ensure that the focus always accurately matches the actual contour of the workpiece.

[0057] This integrated solution achieves closed-loop control of "perception-decision-execution": the depth camera 6 provides high-precision 3D perception capabilities, the control module completes spatial mapping and focus trajectory planning, and the dynamic zoom component 2 performs millisecond-level focus adjustment. The three work together to solve the fundamental problem that traditional equipment cannot adapt to free-form surface processing. Since the depth camera 6 and the field lens 4 are mounted on the same base plate 5, calibration drift caused by relative displacement is avoided, ensuring long-term consistency between 3D data and processing coordinates. At the same time, the entire focusing process does not require moving the workpiece or laser head, completely avoiding vibration and delay introduced by mechanical motion, and significantly improving the accuracy, efficiency, and edge sharpness of complex surface engraving.

[0058] In some examples, the depth camera 6 is configured as a binocular stereo camera with a measurement accuracy of ±0.1 mm; the control module includes a main control board and a dedicated FPGA or DSP chip, which can calculate the Z-axis compensation in real time and output it synchronously to the dynamic zoom driver and galvanometer controller; the fixed base plate 5 is made of aluminum alloy or Invar steel, which has high rigidity and low thermal deformation characteristics; the system is suitable for application scenarios with strict requirements for three-dimensional adaptability, such as jewelry curved surface marking, irregular shape engraving of mobile phone cases, mold repair and personalized cultural and creative products.

[0059] According to an embodiment of the second aspect of this application, the control method applied to the above-described laser engraving machine includes: Step S1: Obtain the 3D image data of the object to be processed; Step S2: Determine the target focus position based on the 3D image data; Step S3: Based on the target focal position, control the operation of the dynamic zoom component 2 so that the focal point of the laser engraving machine's beam acts on the target focal position.

[0060] It is understood that this application provides a control method for a laser engraving machine, which includes a dynamic zoom component 2, a light reflection component 3, a field lens 4, and a depth camera 6. This control method is primarily executed by a control module and specifically includes the following steps: Step S1: Obtain the three-dimensional image data of the object to be processed.

[0061] The control module activates depth camera 6, which performs a non-contact scan of the object to be processed, thereby acquiring three-dimensional image data of the object's surface. Three-dimensional image data refers to a point cloud set containing the lateral position and height information of each point on the object's surface in a spatial Cartesian coordinate system, where each point has a unique lateral coordinate and a corresponding height coordinate. For example, depth camera 6 employs a binocular stereo vision principle, simultaneously capturing images of the object from different perspectives using two imaging units. The height of each point on the object's surface relative to the reference plane of depth camera 6 is then calculated based on parallax, ultimately generating three-dimensional point cloud data covering the entire area to be processed. In one specific embodiment, depth camera 6 is a structured light 3D scanner, which projects an coded grating pattern onto the object and captures the deformed pattern using a single high-resolution camera. A phase-shifting algorithm is used to calculate the precise three-dimensional shape of the object's surface, resulting in a spatial resolution of at least four sampling points per square millimeter for the obtained three-dimensional image data.

[0062] Step S2: Determine the target focus position based on the 3D image data.

[0063] The control module receives the 3D image data acquired in step S1 and maps the preset 2D engraving pattern onto the surface represented by the 3D image data, thereby determining the specific position where the laser beam should act at each moment during the processing. This position is the target focal point position. The target focal point position refers to the spatial coordinates of the high-energy-density focal point that the laser beam needs to form on the surface of the object to be processed, which is defined by both the horizontal and vertical coordinates. Specifically, the control module first performs surface reconstruction processing on the 3D image data to generate a continuous 3D surface model; then, it performs conformal mapping of the user-input 2D vector graphics according to the geometric features of the surface model, so that each processing trajectory point in the graphic corresponds to an actual physical point on the surface; finally, it extracts the height coordinates of the physical point as the basis for adjusting the target focal point position in the optical axis direction. In a specific embodiment, the control module uses a triangular mesh interpolation algorithm to fit the discrete point cloud to the surface, and then uses parametric mapping to fit the circular engraving pattern onto the surface of a spherical workpiece, thereby obtaining a series of target focal points distributed along the spherical surface, each position containing a precise Z-axis height value.

[0064] Step S3: Based on the target focal position, control the operation of the dynamic zoom component 2 so that the focal point of the laser engraving machine's beam acts on the target focal position.

[0065] Based on the height coordinates of the target focal position determined in step S2, the control module calculates the required adjustment displacement of the movable lens in the dynamic zoom assembly 2 and outputs a corresponding drive signal to the actuator of the dynamic zoom assembly 2, thereby adjusting the focusing depth of the beam in real time to ensure that the laser focus always accurately acts on the target focal position. The dynamic zoom assembly 2 includes a first concave lens 22 that can move along the optical axis, a fixed first convex lens 23, and a fixed second convex lens 24. There is a defined optical function relationship between the focal position and the position of the first concave lens 22. The control module internally stores a mapping table or analytical expression of this function relationship. When the height coordinates of the target focal position are input, the target displacement of the first concave lens 22 can be obtained by looking up the table or numerical calculation. Subsequently, the control module sends a pulse command to the drive motor, which drives the lead screw mechanism to move the first concave lens 22 to the designated position. In one specific embodiment, the control module calls a pre-calibrated optical transfer function according to the instruction that the target focal point needs to be offset upward by 2.3 mm, calculates that the first concave lens 22 should move 0.18 mm towards the light source, and outputs a corresponding number of stepping pulses to the micro linear motor, so that the first concave lens 22 completes the positioning within 5 milliseconds, thereby causing the beam focal point to move upward by 2.3 mm synchronously and fall precisely on the specified point on the workpiece surface.

[0066] Through the overall scheme of steps S1 to S3 described above, the control module achieves closed-loop control from 3D perception to dynamic focusing: First, the depth camera 6 acquires the true 3D shape of the workpiece; then, the processing graphic is accurately mapped onto this shape to determine the target focal position of each processing point; finally, the dynamic zoom component 2 is driven to adjust the beam focal depth in real time, ensuring that the focal point remains in contact with the actual surface of the complex curved surface throughout the entire engraving process. This method eliminates the need to move the workpiece or laser head, avoiding mechanical inertia and vibration interference, significantly improving the processing accuracy and edge sharpness of free-form surfaces (such as spheres and irregular curved surfaces), while also expanding the effective processing area and solving the defocusing degradation problem caused by a fixed focal plane in related technologies.

[0067] In some embodiments, the dynamic zoom component 2 includes a first concave lens 22, a first convex lens 23, and a second convex lens 24. The first concave lens 22, the first convex lens 23, and the second convex lens 24 are sequentially disposed on the propagation path of the emitted light of the light source component 1, and the light reflection component 3 is located on the propagation path of the emitted light of the second convex lens 24. The steps for controlling the operation of the dynamic zoom component 2 based on the target focus position include: Based on the target focal position, determine the target movement distance of the first concave lens 22; Based on the target moving distance, control the movement of the first concave lens 22.

[0068] It is understood that this application provides a control method for a laser engraving machine. The laser engraving machine includes a light source assembly 1, a dynamic zoom assembly 2, a light reflection assembly 3, and a field lens 4. The dynamic zoom assembly 2 includes a first concave lens 22, a first convex lens 23, and a second convex lens 24. The first concave lens 22, the first convex lens 23, and the second convex lens 24 are sequentially disposed on the propagation path of the emitted light from the light source assembly 1. The light reflection assembly 3 is located on the propagation path of the emitted light from the second convex lens 24. This control method is executed primarily by a control module and specifically includes the following steps: Step 1: Determine the target movement distance of the first concave lens 22 based on the target focal position.

[0069] The control module receives the target focal position determined in the preceding steps. This target focal position represents the spatial height coordinates of the focal point that the laser beam needs to form on the surface of the object to be processed. Based on these height coordinates, the control module calls a pre-stored optical mapping relationship to calculate the target movement distance required for the first concave lens 22. The target movement distance refers to the linear displacement that the first concave lens 22 needs to produce relative to its reference mounting position along the optical axis. This displacement is adjusted by changing the relative distance between the first concave lens 22 and the first convex lens 23 and the second convex lens 24, thereby adjusting the equivalent focal length of the entire dynamic zoom assembly 2 and ultimately controlling the focusing depth of the output beam. The optical mapping relationship is a nonlinear function obtained through system calibration or optical design simulation. Its input is the Z-axis offset of the focal position, and its output is the axial displacement of the first concave lens 22. In one specific embodiment, when the target focal position needs to be moved down 2.0 mm from the standard plane, the control module queries the calibration data table to determine that the first concave lens 22 should be moved 0.15 mm away from the first convex lens 23. This value has taken into account the optical leverage amplification effect of the conjugate imaging system composed of the first convex lens 23 and the second convex lens 24 on the small displacement, ensuring that the sensitivity and travel range of the focal adjustment meet the requirements of three-dimensional curved surface processing.

[0070] Step 2: Based on the target moving distance, control the movement of the first concave lens 22.

[0071] The control module generates a corresponding drive command based on the target movement distance determined in step one, and sends the drive command to the moving component 21 connected to the first concave lens 22. The moving component 21 drives the first concave lens 22 to move precisely to the target position along the optical axis. The moving component 21 is an actuator fixedly connected to the first concave lens 22, and its type includes a micro stepper motor with a precision ball screw, a piezoelectric ceramic actuator, or a voice coil motor. The drive command is an electrical signal proportional to the target movement distance, and its form includes the number of pulses, analog voltage values, or digital position codes. In a specific embodiment, the control module outputs 225 pulse signals to the stepper motor driver, each pulse corresponding to a mechanical displacement resolution of 0.00067 mm, thereby driving the lead screw to push the first concave lens 22 to complete a precise movement of 0.15 mm and reach a stable state within 5 milliseconds, ensuring that the laser focus acts synchronously and without lag on the target focus position.

[0072] Through the overall scheme of steps one and two described above, the control module accurately converts the target focal position into a physical displacement command for the first concave lens 22, and achieves rapid execution through the high-response, high-precision moving component 21, enabling the dynamic zoom component 2 to adjust the beam focal depth in real time during laser scanning. This scheme fully utilizes the structural characteristics of the first concave lens 22 as a dynamic focusing element, combined with the nonlinear optical lever effect, to achieve a wide range of focal adjustment with minimal mechanical displacement. Simultaneously, since focal control relies entirely on the movement of the internal lens, without requiring movement of the entire machine or workpiece, it completely avoids mechanical inertia and vibration interference, significantly improving the processing accuracy and edge sharpness of complex free-form surfaces (such as spheres and irregular curved surfaces), and effectively expanding the effective depth of field and usable processing area, thus solving the defocusing degradation problem caused by a fixed focal plane in related technologies.

[0073] In some embodiments, the step of determining the target movement distance of the first concave lens 22 based on the target focal position includes: The focal movement distance is determined based on the current focal position and the target focal position of the laser engraving machine's beam; The target movement distance is determined based on the focal point movement distance, the focal length of the first convex lens 23, and the focal length of the second convex lens 24.

[0074] It is understood that this application provides a control method for a laser engraving machine. The laser engraving machine includes a light source assembly 1, a dynamic zoom assembly 2, a light reflection assembly 3, and a field lens 4. The dynamic zoom assembly 2 includes a first concave lens 22, a first convex lens 23, and a second convex lens 24, which are sequentially positioned along the propagation path of the emitted light from the light source assembly 1. This control method is executed primarily by a control module and specifically includes the following steps: Step 1: Determine the focal movement distance based on the current focal position of the laser engraving machine's beam and the target focal position.

[0075] The control module acquires the current focal position and the target focal position, and calculates the difference between them along the optical axis. This difference is the focal movement distance. The current focal position refers to the spatial height coordinates of the laser beam actually focused on the surface to be processed when performing the current processing action; the target focal position refers to the spatial height coordinates of the next processing point to be focused on, determined based on the three-dimensional shape of the object to be processed; the focal movement distance is the algebraic difference between the two, and its positive or negative sign indicates the direction in which the focal point needs to be adjusted upwards or downwards along the optical axis. In a specific embodiment, the current focal position is located on the standard processing plane (height defined as 0 mm), while the target focal position needs to be moved upwards to +1.8 mm due to the curvature of the workpiece surface. Therefore, the focal movement distance is +1.8 mm, indicating that the focal point needs to be moved 1.8 mm away from the surface to be processed.

[0076] Step 2: Determine the target movement distance based on the focal point movement distance, the focal length of the first convex lens 23, and the focal length of the second convex lens 24.

[0077] The control module calculates the target movement distance required for the first concave lens 22 based on the focal length obtained in step one, combined with the focal lengths of the first convex lens 23 and the second convex lens 24, using a pre-stored optical transfer function. The focal length of the first convex lens 23 is a measure of its ability to converge parallel incident light, and its value is positive. The focal length of the second convex lens 24 is a corresponding optical parameter, also with a positive value. In a preferred embodiment, the second convex lens 24 employs a cemented doublet achromatic structure to accommodate multi-wavelength lasers. The optical transfer function is a nonlinear mapping relationship derived from the Gaussian optics formula, and its form is: the target movement distance is equal to an analytical expression determined by the focal length movement distance, the focal length of the first convex lens 23, and the focal length of the second convex lens 24. This expression reflects the amplification effect between the change in lens spacing within the dynamic zoom assembly 2 and the output focal displacement. In one specific embodiment, the focal length of the first convex lens 23 is known to be 50 mm, the focal length of the second convex lens 24 is known to be 100 mm, and the focal point movement distance is +1.8 mm. The control module calls the calibrated transfer function to perform numerical calculations and obtains that the target movement distance of the first concave lens 22 is -0.14 mm (the negative sign indicates movement towards the first convex lens 23). This result has been experimentally verified to make the focal point move up precisely by 1.8 mm.

[0078] Through the overall scheme described in steps one and two above, the control module transforms the focus position adjustment requirement into a precise lens displacement command based on the system's inherent optical parameters. This method fully utilizes the nonlinear optical lever structure formed by the first concave lens 22, the first convex lens 23, and the second convex lens 24 in the dynamic zoom component 2, enabling even a small lens displacement to drive a large range of depth changes in the focus. Simultaneously, by explicitly introducing the focal lengths of the first convex lens 23 and the second convex lens 24 as calculation parameters, it ensures a high degree of consistency between the control model and the actual optical path characteristics, significantly improving the accuracy and robustness of focus control. Thus, without relying on external mechanical movement, real-time, high-precision dynamic focusing on any three-dimensional curved surface is achieved, effectively overcoming the defects of traditional fixed focal plane systems in complex contour processing, such as defocusing, blurring, and limited area, ensuring the clarity of the engraved edges and processing consistency.

[0079] In some preferred embodiments, the dynamic zoom component 2 is composed of a first concave lens 22, a first convex lens 23, and a second convex lens 24, wherein the focal length of the first convex lens 23 is denoted as f2, and the focal length of the second convex lens 24 is denoted as f3, both of which are positive numbers; when it is necessary to move the focal point of the laser beam from the reference plane by ZZ millimeters, the control module calculates the distance ΔS that the first concave lens 22 needs to move according to the pre-calibrated optical system parameters using the following formula: Where ΔS is the displacement of the first concave lens 22 along the optical axis relative to its initial position, in millimeters; Z is the offset of the target focal point position relative to the reference plane, in millimeters. This formula is derived based on the Gaussian optical imaging principle and reflects the nonlinear optical leverage effect of the three-lens structure inside the dynamic zoom component 2, that is, a small lens displacement can cause a large change in focal depth. After receiving the target focal point position, the control module calls this formula to perform numerical calculation to obtain ΔS, and generates a drive command accordingly to drive the moving component 21 to push the first concave lens 22 to move a corresponding distance, thereby achieving high-precision, real-time control of the laser focal point position.

[0080] The introduction of this formula allows the control system to directly map the focal position to the lens displacement without relying on experimental table lookups, significantly improving control response speed and mathematical modeling accuracy. It is particularly suitable for closed-loop control requirements in high-speed, continuous zoom scenarios. Furthermore, the formula is applicable to different wavelengths (such as 450nm and 1064nm), ensuring the compatibility and consistency of the dual-wavelength confocal system.

[0081] In some embodiments, the step of determining the target movement distance includes: The target distance between the first concave lens 22 and the second convex lens 24 is determined based on the focal shift distance, the focal length of the first convex lens 23, and the focal length of the second convex lens 24. Obtain the actual distance between the first concave lens 22 and the second convex lens 24; The target's movement distance is determined based on the actual distance and the target distance.

[0082] It is understood that this application provides a control method for a laser engraving machine. The laser engraving machine includes a light source assembly 1, a dynamic zoom assembly 2, a light reflection assembly 3, and a field lens 4. The dynamic zoom assembly 2 includes a first concave lens 22, a first convex lens 23, and a second convex lens 24, which are sequentially positioned along the propagation path of the emitted light from the light source assembly 1. This control method is executed primarily by a control module and specifically includes the following steps: Step 1: Based on the focal point movement distance, the focal length of the first convex lens 23, and the focal length of the second convex lens 24, determine the target distance between the first concave lens 22 and the second convex lens 24.

[0083] The control module calculates the target distance between the first concave lens 22 and the second convex lens 24 required to achieve the focus movement based on the known focus movement distance and the focal lengths of the first convex lens 23 and the second convex lens 24, using a pre-stored optical design model. The focus movement distance refers to the difference between the current focus position and the target focus position along the optical axis. The focal length of the first convex lens 23 refers to its converging capability parameter for the incident beam, and its value is positive. The focal length of the second convex lens 24 refers to its corresponding optical parameter, which is also positive, and in a preferred embodiment, a double-cemented achromatic structure is used to correct multi-wavelength dispersion. The target distance refers to the ideal distance along the optical axis between the image-side principal plane of the first concave lens 22 and the object-side principal plane of the second convex lens 24 within the dynamic zoom assembly 2; this distance directly determines the focusing depth of the output beam. In one specific embodiment, when the focal point moves by a distance of +2.0 mm (indicating that the focal point needs to be moved upward), the focal length of the first convex lens 23 is 45 mm, and the focal length of the second convex lens 24 is 90 mm, the control module calls the mapping relationship derived from the Gaussian optical formula to calculate that the target distance between the first concave lens 22 and the second convex lens 24 should be 138.5 mm.

[0084] Step 2: Obtain the actual distance between the first concave lens 22 and the second convex lens 24.

[0085] The control module reads the real-time signal fed back by the position sensor mounted on the moving part 21 to obtain the actual distance between the first concave lens 22 and the second convex lens 24. The actual distance refers to the true physical distance between the first concave lens 22 and the second convex lens 24 along the optical axis at the current moment. The position sensor is a high-precision displacement detection device integrated with the moving part 21, and its type includes, but is not limited to, a magnetostrictive displacement sensor, a grating ruler, or a Hall element. It is used to monitor the position of the first concave lens 22 in real time and indirectly calculate the distance between it and the fixedly mounted second convex lens 24. In one specific embodiment, the position sensor outputs an analog voltage signal, which the control module converts into a digital quantity using an analog-to-digital converter, and calculates the current actual distance as 138.7 mm based on a calibration coefficient.

[0086] Step 3: Determine the target's movement distance based on the actual distance and the target distance.

[0087] The control module compares the target distance determined in step one with the actual distance obtained in step two, and calculates the absolute value and direction of the difference between the two. This difference is the target movement distance that the first concave lens 22 needs to adjust. The target movement distance refers to the displacement that the first concave lens 22 needs to move along the optical axis, and its sign indicates the direction of movement (positive indicates moving away from the second convex lens 24, negative indicates moving closer to the second convex lens 24). In a specific embodiment, the target distance is 138.5 mm, and the actual distance is 138.7 mm. Then the target movement distance is -0.2 mm, which means that the first concave lens 22 needs to move 0.2 mm closer to the second convex lens 24 to achieve the required optical configuration of the system.

[0088] Through the overall scheme of steps one through three described above, the control module realizes closed-loop calculation from focus adjustment requirements to precise lens displacement: firstly, based on optical principles, the focus movement is converted into an ideal lens spacing; then, the current state is acquired through real-time sensing; and finally, precise displacement correction commands are generated. This method fully combines the structural characteristics of the dynamic zoom component 2 with the closed-loop feedback mechanism, which not only improves the accuracy of focus adjustment but also effectively compensates for static errors caused by mechanical backlash, thermal drift, or assembly tolerances. Therefore, even during high-speed scanning, the focus can maintain close tracking of the three-dimensional curved surface, significantly improving the processing quality of complex free-form surfaces (such as spheres and irregularly shaped shells), avoiding problems such as edge defocusing and blurred lines, while enhancing the system's stability and repeatability during long-term operation, and solving the focusing deviation problem caused by open-loop control in related technologies.

[0089] In some embodiments, the step of determining the target focus position based on three-dimensional image data includes: Based on the 3D image data acquired by depth camera 6, the surface geometry of the object to be processed is reconstructed to obtain the 3D curved surface of the surface to be processed. Based on the preset two-dimensional carving graphic and the three-dimensional surface of the surface to be processed, each graphic point of the two-dimensional carving graphic is mapped to the three-dimensional surface of the surface to be processed to obtain the three-dimensional carving trajectory corresponding to the two-dimensional carving graphic. Based on the 3D carving trajectory, the Z-axis coordinate value of each trajectory point in space is extracted to obtain the focus height sequence; Based on the focal height sequence and combined with the working distance parameters of the field lens 4 of the laser engraving machine, the target focal position corresponding to each trajectory point is calculated.

[0090] Understandably, this application provides a method for determining the target focal position of a laser engraving machine based on three-dimensional image data. This method acquires three-dimensional image data of the object to be processed using a depth camera 6, and calculates the target focal position corresponding to each trajectory point by combining preset two-dimensional engraving graphics and the working distance parameters of the field lens 4. The specific implementation steps are as follows: Step 1: Reconstruct the surface geometry of the object to be processed to obtain the three-dimensional surface of the surface to be processed.

[0091] First, a depth camera 6 is used to scan the object to be processed, acquiring its 3D image data. The depth camera 6 can be a structured light 3D scanner, a Time-of-Flight (TOF) camera, or a stereo vision system, capable of accurately capturing the depth information of the object's surface. Then, based on this depth information, computer-aided design (CAD) software or specific algorithms (such as triangulation mesh generation algorithms) are used to reconstruct the surface geometry of the object to be processed, thereby obtaining a precise 3D surface model of the surface to be processed. This step ensures that the 3D surface used in subsequent processing has high accuracy and detail retention.

[0092] Step 2: Map the two-dimensional engraved graphic onto the three-dimensional curved surface of the surface to be processed to obtain the three-dimensional engraving trajectory corresponding to the two-dimensional engraved graphic.

[0093] After obtaining the 3D surface of the surface to be processed, based on the preset 2D carving graphic, coordinate transformation and projection techniques are used to map each point on the 2D carving graphic to its corresponding position on the 3D surface. This process involves complex mathematical operations, including but not limited to coordinate system transformation, nonlinear transformation, and possible interpolation operations, to ensure that the 2D graphic can adapt to the complex shape of the 3D surface without distortion. Finally, a 3D carving trajectory is generated that corresponds to the original 2D carving graphic but is adapted to the geometric features of the actual surface to be processed.

[0094] Step 3: Extract the spatial Z-axis coordinates of each trajectory point in the 3D carving trajectory to form a focus height sequence.

[0095] Along the established 3D carving trajectory, the Z-axis coordinates of each trajectory point in its spatial location are extracted, representing its height relative to the reference plane. These height values ​​constitute the so-called "focal height sequence," which represents the different height positions that the laser beam focus needs to reach throughout the carving process, ensuring that the carved pattern can be accurately presented on the 3D curved surface as expected.

[0096] Step 4: Combine the working distance parameters of the laser engraving machine's field lens 4 to calculate the target focal position corresponding to each trajectory point.

[0097] Finally, considering the working characteristics and focusing mechanism of the field lens 4 in the laser engraving machine, and based on the previously obtained focal height sequence and the working distance parameters of the field lens 4 (e.g., the optimal focusing range of the field lens 4), the optimal focal position corresponding to each trajectory point is calculated. Here, the working distance refers to the effective distance range from the field lens 4 to the final clear imaging point, which directly affects the engraving quality. By reasonably setting and adjusting this parameter, it can be ensured that the laser energy is concentrated and stably applied to the workpiece surface, thereby achieving a high-quality engraving effect.

[0098] In summary, the method described above, through data acquired by the depth camera 6 and advanced image processing technology, achieves a precise conversion from 2D design to 3D physical engraving. This not only improves engraving efficiency and accuracy but also enhances the ability to handle complex curved surfaces, solving the problem that traditional planar engraving struggles with three-dimensional workpieces and greatly expanding the application areas and technological possibilities of laser engraving. Furthermore, the highly automated process reduces the possibility of human intervention, further improving production consistency and stability.

[0099] In some embodiments, the steps of controlling the operation of the dynamic zoom component 2 based on the target focus position include: Based on the target focus location, a sequence of target focus locations is obtained; Based on the target focus position sequence, during the engraving process, the target focus positions are output sequentially to the control interface of the dynamic zoom component 2 in chronological order, so that the dynamic zoom component 2 can adjust the position of the beam focus in real time.

[0100] It is understood that this application provides a control method for a laser engraving machine, which includes a light source assembly 1, a dynamic zoom assembly 2, a light reflection assembly 3, a field lens 4, and a control module. The control method is primarily executed by the control module and specifically includes the following steps: Step 1: Obtain the target focus position sequence based on the target focus position.

[0101] The control module receives multiple target focal positions determined by the aforementioned processing steps and sorts them according to the scanning path order of the laser beam on the surface to be processed, forming a target focal position sequence. A target focal position refers to the spatial coordinates required for focusing at each trajectory point on the three-dimensional engraving trajectory, including lateral and height coordinates. The target focal position sequence is an ordered set arranged chronologically or in scanning order, used to guide the dynamic zoom component 2 to adjust the focal depth point by point during the engraving process. In a specific embodiment, when the two-dimensional engraving graphic is a circle with a diameter of 20 mm mapped onto a spherical cap surface, the control module discretizes the circumference into 500 trajectory points and generates a corresponding sequence containing 500 target focal positions, each position marked with its Z-axis height value and the corresponding scanning time.

[0102] Step 2: Based on the target focus position sequence, during the engraving process, the target focus positions are output sequentially to the control interface of the dynamic zoom component 2 in chronological order, so that the dynamic zoom component 2 can adjust the position of the beam focus in real time.

[0103] After initiating the engraving operation, the control module extracts the target focus positions sequentially from the target focus position sequence according to the preset scanning speed and trajectory planning, converts them into corresponding control commands, and sends them to the control interface of the dynamic zoom component 2 in real time. The control interface is the electronic input port of the driving moving part 21 (such as a micro stepper motor or piezoelectric actuator) in the dynamic zoom component 2; the control commands include the focus depth value corresponding to the target focus position or the displacement of the first concave lens 22 directly corresponding to it. After receiving the command, the dynamic zoom component 2 immediately drives the first concave lens 22 to move to the designated position, thereby changing the focusing depth of the beam and making the laser focus synchronously act on the target focus position of the current trajectory point. In a specific embodiment, the control module reads the next target focus position from the sequence at a frequency of once per millisecond and sends the Z-axis offset (e.g., +1.35 mm) to the drive controller of the dynamic zoom component 2 through the serial communication bus. The latter completes the lens positioning within 2 milliseconds to ensure that the focus is accurately in place before the galvanometer scans to that point.

[0104] Through the overall scheme of steps one and two described above, the control module achieves highly efficient and synchronized control of the dynamic zoom component 2: the target focal position is organized into a sequence strictly aligned with the scanning timing, and output to the dynamic zoom component 2 point by point in real time during the engraving process, enabling it to pre-adjust the focal depth before the laser beam reaches each processing point. This method fully utilizes the advantages of the dynamic zoom component 2's fast response and lack of mechanical inertia, achieving millisecond-level coordination between the focal position and the XY scanning coordinates, effectively solving the problem of blurred or dispersed energy in curved surface processing caused by focal lag under high-speed scanning. Thus, without moving the entire machine or workpiece, it ensures that each engraving point on complex three-dimensional curved surfaces (such as freeform surfaces, stepped surfaces, or multi-curvature transition areas) obtains the optimal focusing state, significantly improving processing accuracy, edge sharpness, and overall consistency, breaking through the performance bottleneck of traditional fixed focal plane systems in dynamic three-dimensional processing.

[0105] In some embodiments, the steps of controlling the operation of the dynamic zoom component 2 based on the target focus position include: The intensity signal of the reflected light is obtained based on the laser scattered light reflected back from the surface to be processed, which is collected by a photodetector. Based on the reflected light intensity signal, determine whether the current reflected light intensity is less than a preset intensity threshold; Based on the judgment result that the current reflected light intensity is less than the preset intensity threshold, the focus offset direction is determined to be away from the surface to be processed; Based on the fact that the focus offset direction is away from the surface to be processed, the dynamic zoom component 2 is controlled to drive the first concave lens 22 to move a first preset fine-tuning distance toward the first convex lens 23; Based on the state after the first concave lens 22 moves a first preset fine-tuning distance, a new reflected light intensity signal is acquired again, and the step of judging whether the current reflected light intensity is less than the preset intensity threshold is repeated until the reflected light intensity signal is greater than or equal to the preset intensity threshold.

[0106] It is understood that this application provides a control method for a laser engraving machine. The laser engraving machine includes a light source assembly 1, a dynamic zoom assembly 2, a light reflection assembly 3, a field lens 4, a photodetector, and a control module. The dynamic zoom assembly 2 includes a first concave lens 22, a first convex lens 23, and a second convex lens 24. The control method is mainly executed by the control module and specifically includes the following steps: Step 1: Obtain the intensity signal of the reflected light based on the laser scattered light reflected back from the surface to be processed, collected by the photodetector.

[0107] During laser engraving, a photodetector receives a portion of the laser energy reflected or scattered from the surface being processed in real time and converts it into an electrical signal. The control module amplifies and filters this electrical signal to obtain a reflected light intensity signal characterizing the current focal state. The photodetector is installed near field lens 4, and its field of view covers the laser focal area, ensuring that the acquired signal accurately reflects the intensity of light-material interaction at the focal point.

[0108] Step 2: Based on the reflected light intensity signal, determine whether the current reflected light intensity is less than the preset intensity threshold.

[0109] The control module compares the reflected light intensity signal obtained in step one with a preset intensity threshold. The preset intensity threshold is a fixed value calibrated based on the typical reflection intensity produced by a specific material under optimal focusing conditions. If the amplitude of the reflected light intensity signal is lower than this threshold, it is determined that the current focus is not accurately applied to the surface to be processed, and there is a defocusing phenomenon.

[0110] Step 3: Based on the judgment result that the current reflected light intensity is less than the preset intensity threshold, the focus offset direction is determined to be away from the surface to be processed.

[0111] When the result indicates that the intensity of reflected light is insufficient, the control module infers based on the optical focusing characteristics: for most non-transparent materials, the focus deviating from the surface (whether upward or downward) usually leads to a decrease in reflection intensity. However, combined with the initial calibration state of the system and the reference position of the processing start point, it can be determined that if the intensity remains low during the current scanning stage, the focus is more likely to be located above the surface to be processed, that is, the offset direction is away from the surface to be processed.

[0112] Step 4: Based on the focus offset direction being away from the surface to be processed, control the dynamic zoom component 2 to drive the first concave lens 22 to move a first preset fine-tuning distance toward the first convex lens 23.

[0113] Based on the focus offset direction obtained in step three, the control module generates a drive command and sends it to the moving component 21 of the dynamic zoom assembly 2. The moving component 21 responds to the command, moving the first concave lens 22 along the optical axis towards the first convex lens 23 by a fixed small displacement, i.e., a first preset fine-tuning distance. This fine-tuning distance is typically 0.02–0.1 mm, sufficient to cause a detectable change in the depth of focus while avoiding over-adjustment oscillation.

[0114] Step 5: Based on the state after the first concave lens 22 moves by the first preset fine-tuning distance, acquire a new reflected light intensity signal again, and repeat the step of judging whether the current reflected light intensity is less than the preset intensity threshold until the reflected light intensity signal is greater than or equal to the preset intensity threshold.

[0115] After the first concave lens 22 completes its fine-tuning, the control module immediately triggers a new round of reflected light acquisition to obtain an updated reflected light intensity signal, and then re-executes the comparison and judgment step two. If the signal is still below the threshold, fine-tuning continues in the same direction; if the signal exceeds the threshold, adjustment stops. This closed-loop process typically converges within 2–5 iterations, ensuring that the focal point quickly returns to its optimal position.

[0116] Through the overall scheme of steps one through five described above, the control module achieves adaptive focus adjustment based on optical feedback: using the surface reflection intensity of the material as a direct criterion for focus quality, and achieving closed-loop correction through small-step, directional lens displacement. This method does not rely on precise 3D models or preset material parameters, and can address instantaneous defocusing caused by workpiece clamping errors, abrupt surface undulations, or differences in local material properties. It significantly improves the robustness and consistency of multi-material and non-flat surface processing, and is particularly suitable for focus-sensitive applications such as high-reflectivity metal marking and composite material engraving.

[0117] In some embodiments, after determining the target focus position based on three-dimensional image data, the method further includes: Based on the spatial coordinates of three consecutive adjacent trajectory points in the 3D carving trajectory, the local radius of curvature at the middle trajectory point is obtained. Based on the local radius of curvature, determine whether the local radius of curvature is less than a preset radius of curvature threshold; Based on the judgment result that the local radius of curvature is less than the preset radius of curvature threshold, it is determined that the intermediate trajectory point belongs to the high curvature region; Based on the fact that the intermediate trajectory point belongs to a high curvature region, the acceleration adjustment of the dynamic zoom component 2 is started at a preset advance time before the laser beam reaches the intermediate trajectory point. Based on a preset lead time, the dynamic zoom component 2 is controlled to start changing the position of the first concave lens 22 before the laser beam reaches the intermediate trajectory point, so that the focus of the beam has already acted on the target focus position corresponding to the intermediate trajectory point when the laser beam reaches the intermediate trajectory point.

[0118] It is understood that this application provides a control method for a laser engraving machine. The laser engraving machine includes a light source assembly 1, a dynamic zoom assembly 2, a light reflection assembly 3, a field lens 4, and a control module. The dynamic zoom assembly 2 includes a first concave lens 22, a first convex lens 23, and a second convex lens 24. This control method is primarily executed by the control module. After determining the target focal position based on three-dimensional image data, it further includes the following steps: Step 1: Based on the spatial coordinates of three consecutive adjacent trajectory points in the 3D carving trajectory, obtain the local radius of curvature at the middle trajectory point.

[0119] The control module sequentially extracts the spatial coordinates of three consecutive adjacent trajectory points from the generated 3D carving trajectory, namely the previous point, the middle point, and the next point. Based on the spatial coordinates of these three points, a minimum curvature circle passing through these three points is determined using geometric calculation methods (such as the three-point circle fitting method), and the radius of this curvature circle is used as the local radius of curvature at the middle trajectory point. This local radius of curvature characterizes the degree of curvature of the carving path near that point.

[0120] Step 2: Based on the local radius of curvature, determine whether the local radius of curvature is less than the preset radius of curvature threshold.

[0121] The control module compares the local radius of curvature obtained in step one with a preset radius of curvature threshold. The preset radius of curvature threshold is an empirical value derived from the response capability of the dynamic zoom component 2 and the laser scanning speed, used to distinguish between gentle areas and high curvature areas. If the local radius of curvature is less than the threshold, the area is determined to be a high rate of change area such as a sharp bend or a sharp angle.

[0122] Step 3: Based on the judgment result that the local radius of curvature is less than the preset radius of curvature threshold, it is determined that the intermediate trajectory point belongs to the high curvature region.

[0123] When the judgment result is that the local radius of curvature is less than the preset radius of curvature threshold, the control module clearly marks the intermediate trajectory point as a key point in the high curvature region, indicating that the laser focus needs to be adjusted to a large depth in a very short time. Otherwise, the focus may deviate from the ideal position due to system response lag.

[0124] Step 4: Based on the fact that the intermediate trajectory point belongs to the high curvature region, determine the preset advance time before the laser beam reaches the intermediate trajectory point to start the acceleration adjustment of the dynamic zoom component 2.

[0125] The control module calculates a fixed preset advance time based on the current scanning speed of the laser beam and the mechanical response delay characteristics of the dynamic zoom component 2; this time ensures that the dynamic zoom component 2 has sufficient time to complete the lens acceleration movement. The control module associates this preset advance time with the intermediate trajectory point as the trigger time for initiating the focus adjustment action.

[0126] Step 5: Based on the preset advance time, control the dynamic zoom component 2 to start changing the position of the first concave lens 22 before the laser beam reaches the intermediate trajectory point, so that the beam focus has acted on the target focus position corresponding to the intermediate trajectory point when the laser beam reaches the intermediate trajectory point.

[0127] When the remaining scanning time of the laser beam from the intermediate trajectory point is equal to the preset advance time, the control module immediately sends a drive command to the dynamic zoom component 2, causing it to start the displacement control of the first concave lens 22 in advance; the dynamic zoom component 2 accelerates the adjustment of the position of the first concave lens 22 accordingly, ensuring that the beam focus is accurately and stably fixed at the target focus position corresponding to the point at the instant when the laser beam actually scans to the intermediate trajectory point.

[0128] Through the overall scheme of steps one through five described above, the control module achieves advanced focus adjustment in high curvature areas: by identifying local geometric features of the trajectory, it actively triggers dynamic zoom before the physical scan arrives, effectively compensating for the inherent delay of the electromechanical system. This method significantly improves the processing quality at sharp angles, small arcs, or inflection points of complex contours, avoiding problems such as "trailing," energy dispersion, or insufficient engraving depth caused by focus lag. Thus, without increasing hardware bandwidth, it enhances the overall machine's ability to reproduce high-precision 3D graphics and edge sharpness, making it particularly suitable for applications with stringent requirements for contour fidelity, such as logo engraving, precision mold engraving, and microstructure replication.

[0129] In some embodiments, the step of determining the target focus position based on three-dimensional image data includes: The number of carving layers is obtained based on the user-defined total carving depth and the preset single-layer carving depth. Based on the number of carving layers and the carving depth of a single layer, the focal height of each layer is obtained; Based on the focal height of each layer, generate a two-dimensional sculpted graphic of the layer corresponding to that focal height. Based on the currently executing Nth layer engraving, control the dynamic zoom component 2 to fix the beam focus at the layer focus height corresponding to the Nth layer; Based on the state where the beam focus is fixed at the layer focus height corresponding to the Nth layer, the light reflection component 3 is controlled to complete the full-field scanning of the two-dimensional engraved graphic corresponding to the Nth layer. Then, the process is switched to the N+1th layer and the step of controlling the dynamic zoom component 2 to fix the beam focus at the layer focus height is repeated until the engraving of all layers is completed.

[0130] It is understood that this application provides a control method for a laser engraving machine. The laser engraving machine includes a light source assembly 1, a dynamic zoom assembly 2, a light reflection assembly 3, a field lens 4, and a control module. The dynamic zoom assembly 2 includes a first concave lens 22, a first convex lens 23, and a second convex lens 24. This control method is primarily executed by the control module, and the step of determining the target focal position based on three-dimensional image data specifically includes the following processes: Step 1: Based on the total carving depth set by the user and the preset single-layer carving depth, obtain the number of carving layers.

[0131] The control module receives the total engraving depth parameter input by the user and the single-layer engraving depth parameter preset by the system. The total engraving depth refers to the vertical depth of the final recess or relief to be achieved on the surface to be processed. The single-layer engraving depth refers to the thickness of material that can be safely removed or modified in a single laser scan. The control module divides the total engraving depth by the single-layer engraving depth and rounds the result up to obtain the number of engraving layers in integer form, ensuring that the total depth is completely covered.

[0132] Step 2: Based on the number of carving layers and the carving depth of a single layer, obtain the layer focal height corresponding to each layer.

[0133] The control module uses the reference surface of the surface to be processed as the zero height reference and assigns the focal position layer by layer downwards starting from the surface layer. For the first layer, its layer focal height is equal to the standard working distance of the field lens 4. For the Nth layer (N≥2), its layer focal height is equal to the standard working distance plus (N-1) times the single-layer engraving depth. Thus, the control module generates a sequence of layer focal heights containing several elements of the engraving layer, with each element corresponding to the precise focal position of the layer.

[0134] Step 3: Based on the focal height of each layer, generate a 2D sculpted graphic corresponding to that focal height.

[0135] The control module replicates the original 2D engraved graphic multiple times to form multiple identical 2D engraved graphics. Each 2D engraved graphic is spatially associated with its corresponding layer focal height, but the horizontal coordinate remains unchanged. All 2D engraved graphics together constitute a layered engraving task set, which is used to guide the layer-by-layer scanning operation.

[0136] Step 4: Based on the currently executing Nth layer engraving, control the dynamic zoom component 2 to fix the beam focus at the layer focus height corresponding to the Nth layer.

[0137] Before starting the engraving of the Nth layer, the control module reads the layer focal height corresponding to the Nth layer and calculates the target position required for the first concave lens 22 accordingly. Then, the control module drives the moving part 21 of the dynamic zoom component 2 to move the first concave lens 22 and lock it at the target position. In this state, the beam output by the dynamic zoom component 2 is focused by the field lens 4, and its focal point is stably applied to the depth plane corresponding to the Nth layer and remains stationary throughout the scanning process of this layer.

[0138] Step 5: Based on the state where the beam focus is fixed at the layer focus height corresponding to the Nth layer, control the light reflection component 3 to complete the full-field scan of the two-dimensional engraved graphic corresponding to the Nth layer, then switch to the N+1th layer and repeat the step of controlling the dynamic zoom component 2 to fix the beam focus at the layer focus height until the engraving of all layers is completed.

[0139] After the focus is locked, the control module activates the light reflection component 3 and controls the galvanometer to complete the full-field scan according to the path of the two-dimensional engraving pattern corresponding to the Nth layer, so as to achieve the complete engraving of the layer. After the scan of the layer is completed, the control module determines whether N is less than the number of engraving layers. If so, it sets N=N+1 and returns to step four to reset the focus height and engrave the next layer. If not, the entire engraving process ends.

[0140] Through the overall scheme described in steps one through five, the control module decomposes the deep engraving task into multiple statically focused thin-layer processing steps, avoiding the control complexity and accuracy fluctuations caused by continuous dynamic focusing over a large depth range. This layered strategy ensures that each layer is completed under optimal focusing conditions, significantly improving the sidewall verticality, bottom flatness, and interlayer consistency of the deep-engraved structure. Simultaneously, since the dynamic zoom component 2 remains stationary within each layer, the bandwidth requirements of the drive mechanism are reduced, improving system stability and long-term operational reliability. This method is particularly suitable for processing scenarios requiring high-precision depth control, such as wood relief carving, deep marking on metal nameplates, ceramic micro-milling, and multi-layer engraving inside transparent materials.

[0141] In some embodiments, the control method further includes: The current temperature value is obtained based on the temperature sensor installed inside the dynamic zoom component 2; The temperature change is obtained based on the current temperature value and the initial temperature value when the equipment is started. Based on the temperature change, query the pre-stored correspondence table between the temperature change and the focus drift to obtain the current focus compensation amount to be applied; Based on the current amount of focus compensation to be applied, the original target focus position is corrected to obtain the corrected target focus position; Based on the corrected target focal position, the dynamic zoom component 2 is controlled to adjust the position of the first concave lens 22 so that the beam focal point acts on the corrected target focal position.

[0142] It is understood that this application provides a control method for a laser engraving machine. The laser engraving machine includes a light source assembly 1, a dynamic zoom assembly 2, a light reflection assembly 3, a field lens 4, a temperature sensor, and a control module. The dynamic zoom assembly 2 includes a first concave lens 22, a first convex lens 23, and a second convex lens 24. The temperature sensor is disposed inside the dynamic zoom assembly 2. The control method is mainly executed by the control module and specifically includes the following steps: Step 1: Obtain the current temperature value based on the temperature sensor installed inside the dynamic zoom component 2.

[0143] During the operation of the laser engraving machine, the control module reads the signal output by the temperature sensor installed inside the dynamic zoom assembly 2 in real time. The temperature sensor is fixed on the mounting bracket of the first convex lens 23 or the second convex lens 24 and can accurately sense the temperature changes of the optical element and its supporting structure. After the control module converts the signal into a digital quantity, it obtains the current temperature value that represents the current thermal state.

[0144] Step 2: Based on the current temperature value and the initial temperature value when the equipment was started, obtain the temperature change.

[0145] The control module calls the initial temperature value recorded at the time of device startup and subtracts the current temperature value obtained in step one from the initial temperature value to obtain the temperature change. The temperature change represents the net increase or decrease in the internal temperature of the dynamic zoom component 2 since the device was started, and its unit is degrees Celsius (°C).

[0146] Step 3: Based on the temperature change, query the pre-stored correspondence table between the temperature change and the focus drift to obtain the current focus compensation amount to be applied.

[0147] The control module accesses a pre-calibrated and stored correspondence table between temperature changes and focus drift in its internal storage unit. This correspondence table is obtained through experimental calibration and records the systematic focus shift patterns caused by material thermal expansion or optical element displacement under different temperature changes. Based on the temperature changes obtained in step two, the control module searches for or interpolates the corresponding focus drift in the table and uses this focus drift as the focus compensation amount to be applied at the moment.

[0148] Step 4: Based on the current focus compensation amount to be applied, correct the original target focus position to obtain the corrected target focus position.

[0149] The control module superimposes the focus compensation amount obtained in step three onto the height coordinate of the original target focus position determined by the 3D image data. If the focus drift is manifested as the focus moving upward, the compensation amount is negative, otherwise it is positive. After this correction, the corrected target focus position is generated, which already includes the cancellation of the current thermal drift effect.

[0150] Step 5: Based on the corrected target focal position, control the dynamic zoom component 2 to adjust the position of the first concave lens 22 so that the beam focal point acts on the corrected target focal position.

[0151] The control module calculates the target movement distance required by the first concave lens 22 based on the corrected target focal position, and sends a drive command to the moving part 21 of the dynamic zoom assembly 2; the moving part 21 responds to the command and drives the first concave lens 22 to move to a new position along the optical axis; in this state, the beam output by the dynamic zoom assembly 2 is focused by the field lens 4, and its focal point is precisely applied to the corrected target focal position, thereby canceling the focal drift caused by temperature.

[0152] Through the overall scheme of steps one through five described above, the control module achieves active compensation for the thermal drift effect: it uses a built-in temperature sensor to monitor the temperature rise of the dynamic zoom component 2 in real time, and quickly obtains the corresponding focus offset through a lookup table, thereby performing feedforward correction on the target focus position. This method does not rely on complex thermodynamic models or online calibration processes, and can maintain the long-term stability of the focus position during long-term continuous processing. It effectively solves problems such as inconsistent processing depth between the first and last parts, blurry graphics, or decreased energy density caused by equipment heating, significantly improving process repeatability and finished product consistency in mass production. It is especially suitable for precision marking and micromachining tasks in industrial-grade high-load operation scenarios.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate this application and are not intended to limit this application. Although this application has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of this application do not depart from the spirit and scope of the technical solutions of this application and should be covered within the scope of the claims of this application.

Claims

1. A laser engraving machine, characterized in that, It includes a light source component, a dynamic zoom component, a light reflection component, and a field lens. The dynamic zoom component and the light reflection component are sequentially disposed on the propagation path of the light emitted from the light source component, and the field lens is disposed on the propagation path of the light emitted from the light reflection component. The light source assembly is used to emit a light beam to the dynamic zoom assembly; The light reflection component is used to reflect the light beam that has passed through the dynamic zoom component to the field lens; The field lens is used to focus the light beam so that the focal point of the beam acts on the surface to be processed. The dynamic zoom component is used to adjust the focal point of the light beam.

2. The laser engraving machine according to claim 1, characterized in that, The dynamic zoom component includes a moving part, a first concave lens, a first convex lens, and a second convex lens. The first concave lens, the first convex lens, and the second convex lens are sequentially disposed on the propagation path of the emitted light of the light source component, and the light reflection component is located on the propagation path of the emitted light of the second convex lens. The movable component is connected to the first concave lens, and the movable component is used to drive the first concave lens to move relative to the first convex lens, so as to change the distance between the first concave lens and the second convex lens.

3. The laser engraving machine according to claim 1, characterized in that, The light source assembly includes a first light source, a second light source, a first light adjustment assembly, a second light adjustment assembly, and a beam combiner. The first light source and the first light adjustment component are arranged opposite to each other. The first light adjustment component is used to expand and collimate the emitted light from the first light source and transmit the resulting first beam to the beam combiner. The second light source and the second light adjustment component are arranged opposite to each other. The second light adjustment component is used to expand and collimate the emitted light from the second light source and transmit the resulting second beam to the beam combiner. The beam combiner is located between the light source assembly and the dynamic zoom assembly. The beam combiner is used to combine the first beam and the second beam and transmit the resulting mixed beam to the dynamic zoom assembly.

4. The laser engraving machine according to claim 3, characterized in that, The light source assembly further includes a reflector. The first light adjustment assembly is located between the first light source and the reflector. The first light adjustment assembly is used to expand and collimate the emitted light from the first light source and transmit the resulting first beam to the reflector. The reflector is used to reflect the first beam to the beam combiner.

5. The laser engraving machine according to claim 3, characterized in that, The first light adjustment component includes a second concave lens and a third convex lens, wherein the second concave lens is located between the first light source and the third convex lens, and the third convex lens is located between the second concave lens and the reflector.

6. The laser engraving machine according to claim 3, characterized in that, The second light adjustment component includes a third concave lens and a fourth convex lens, wherein the third concave lens is located between the fourth convex lens and the second light source, and the fourth convex lens is located between the reflector and the third concave lens.

7. The laser engraving machine according to any one of claims 1 to 6, characterized in that, The light reflection component includes a first galvanometer and a second galvanometer that are parallel to each other. The first galvanometer is located on the propagation path of the emitted light from the dynamic zoom component. The first galvanometer is used to reflect the light beam passing through the dynamic zoom component to the second galvanometer, and the second galvanometer is used to reflect the light beam to the field lens.

8. The laser engraving machine according to any one of claims 1 to 6, characterized in that, The laser engraving machine also includes a fixed base plate, a depth camera, and a control module. The depth camera and the field lens are mounted on the same side of the fixed base plate. The control module is connected to the fixed base plate. The depth camera is electrically connected to the control module. The depth camera is used to acquire three-dimensional image data of the object to be processed. The control module is configured to: determine control parameters based on the three-dimensional image data acquired by the depth camera; and control the operation of the dynamic zoom component according to the control parameters.

9. A control method for a laser engraving machine as described in any one of claims 1 to 8, characterized in that, include: Acquire 3D image data of the object to be processed; Based on the three-dimensional image data, the target focus position is determined; Based on the target focal position, the operation of the dynamic zoom component is controlled so that the focal point of the laser engraving machine's beam acts on the target focal position.

10. The control method according to claim 9, characterized in that, The dynamic zoom component includes a first concave lens, a first convex lens, and a second convex lens. The first concave lens, the first convex lens, and the second convex lens are sequentially disposed on the propagation path of the emitted light from the light source component. The light reflection component is located on the propagation path of the emitted light from the second convex lens. The step of controlling the operation of the dynamic zoom component based on the target focus position includes: Based on the target focal position, determine the target movement distance of the first concave lens; Based on the target moving distance, control the movement of the first concave lens.

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