Self-adaptive cutting method and system based on femtosecond laser

Abstract

The invention relates to a self-adaptive cutting method and system based on femtosecond laser applied to the technical field of laser precision machining. The method comprises the steps that the thickness parameter of a to-be-cut material is obtained and compared with a preset threshold value; if the thickness is larger than the threshold value, an optical system is controlled to guide laser to a Bessel optical system for longitudinal cutting; and if the thickness is smaller than or equal to the threshold value, guiding to a time compression and space dispersion system for transverse cutting. The system comprises a femtosecond laser, a longitudinal and transverse cutting optical system, a Bessel optical system, a time compression and space dispersion system and a controller. Two sets of optical systems are integrated and switched in a self-adaptive mode, the technical contradiction that a single system cannot give consideration to longitudinal cutting of thick materials and transverse precision cutting of thin materials is solved, and high-quality one-key type machining of brittle and hard materials with the thickness ranging from the micron level to the centimeter level is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to a cutting method and system, in particular to a self-adaptive cutting method and system based on femtosecond laser applied to the field of laser precision machining technology. BACKGROUND

[0002] Laser cutting technology has been widely used in brittle and hard material processing field due to its high precision, non-contact and other advantages. Femtosecond laser can realize "cold processing" and significantly reduce the heat affected zone due to its ultra-short pulse and ultra-high peak power characteristics, becoming an ideal tool for precision machining.

[0003] However, the existing femtosecond laser cutting technology has significant limitations when facing different surface types and thicknesses of brittle and hard materials:

[0004] Longitudinal cutting problem: for materials with large thickness (such as >100 μm), the traditional focused Gaussian beam has uneven energy distribution along the depth direction, which easily leads to overburning at the top and incomplete cutting at the bottom of the material, and large cutting taper and poor cutting quality.

[0005] Transverse cutting problem: for thin or high-precision edge materials (such as thickness ≤10 μm), although femtosecond laser has small heat affected zone, the traditional method still has hundreds of microns of heat affected zone, which easily leads to cracking of thin brittle materials. At the same time, spatial dispersion and temporal broadening occur during laser pulse transmission and focusing, leading to spot distortion and peak power reduction inside the material, resulting in insufficient cutting precision and efficiency.

[0006] Lack of versatility and flexibility: the existing technical solutions have single function, and a set of system is usually optimized for a specific thickness or cutting direction. When the thickness of the processed object changes, the equipment needs to be replaced or the optical path needs to be adjusted complexly, which cannot realize the intelligent adaptive cutting mode of "one-key switching" according to the thickness requirement of the material, and the equipment has poor versatility and is complicated to operate.

[0007] Therefore, there is an urgent need in the art for a high-efficiency and high-precision femtosecond laser cutting solution that can adapt to different thickness materials and balance longitudinal deep cutting and transverse precision cutting. SUMMARY

[0008] The present application aims to overcome the shortcomings of the prior art and provide a self-adaptive cutting method and system based on femtosecond laser, which aims to solve the technical contradiction that the prior art cannot adaptively select the optimal cutting mode according to the material thickness, and realize high-quality and high-efficiency "one-key" invisible cutting from micron-level thin sheets to centimeter-level thick brittle and hard materials.

[0009] To achieve the above purpose, in a first aspect, the present application provides a self-adaptive cutting method based on femtosecond laser, comprising the following steps:

[0010] acquire a thickness parameter of the material to be cut, and compare the thickness parameter with a predetermined threshold value;

[0011] if the thickness parameter is greater than the predetermined threshold value, control the longitudinal and lateral cutting optical system to direct the femtosecond laser beam to a Bessel optical system; the Bessel optical system converts the beam into a Bessel beam by means of a conical lens, and focuses the Bessel beam into the material by means of a lens group for longitudinal cutting;

[0012] if the thickness parameter is less than or equal to the predetermined threshold value, control the longitudinal and lateral cutting optical system to direct the femtosecond laser beam to a time compression and spatial dispersion system; the time compression and spatial dispersion system performs spatial dispersion on the beam by means of a reflective grating, and reflects the dispersed beam back to the reflective grating by means of a mirror pair composed of a first mirror and a second mirror for collimation, and finally time and spatially focuses the collimated parallel spectrum into the material for lateral cutting.

[0013] Preferably, the predetermined threshold value is 10 μm.

[0014] Preferably, the lens group is a 4f lens system composed of a first focusing mirror and a second focusing mirror, which is used to adjust the focal depth and spot diameter of the Bessel beam.

[0015] Preferably, in the time compression and spatial dispersion system, time dispersion compensation is performed on the collimated parallel spectrum to re-synchronize different wavelength components in time.

[0016] Preferably, in the time compression and spatial dispersion system, the optical path between the first mirror and the second mirror and the reflective grating is adjusted by driving an axial displacement platform to achieve time dispersion compensation.

[0017] The time dispersion compensation is used to achieve time and spatial focusing of the laser pulse when focused.

[0018] As a further improvement of the present application, during the cutting process, the following steps are further included:

[0019] real-time acquisition of a monitoring signal reflecting the cutting quality;

[0020] comparison of the monitoring signal with a preset quality threshold value;

[0021] if the monitoring signal is worse than the quality threshold value, control the longitudinal and lateral cutting optical system to dynamically switch the cutting mode.

[0022] Preferably, the monitoring signal is a laser-induced plasma spectrum signal.

[0023] Preferably, the monitoring signal being worse than the quality threshold value means that the continuous background spectrum intensity representing incomplete vaporization of the material is lower than a preset intensity threshold value.

[0024] Preferably, the dynamic switching of cutting modes is as follows: temporarily switch from the current main cutting mode to another fine-tuning cutting mode, and then switch back to the main cutting mode after the fine-tuning is completed.

[0025] Preferably, the main cutting mode and the fine cutting mode correspond to two different cutting modes provided by the Bessel optical system and the time compression and spatial dispersion system, respectively.

[0026] On the other hand, the present invention provides an adaptive cutting system based on femtosecond laser, comprising:

[0027] Femtosecond laser;

[0028] The longitudinal and transverse cutting optical system has its optical input end connected to a femtosecond laser, and its optical output end can be switched to a Bessel optical system or a time compression and spatial dispersion system.

[0029] A Bessel optical system comprises a conical lens and a lens group arranged sequentially along the optical path;

[0030] The time compression and spatial dispersion system includes a laser beam expander, a reflective grating, and a first and second reflector arranged perpendicularly to each other along the optical path.

[0031] The controller, which is connected to the longitudinal and transverse cutting optical system, is configured to receive thickness parameters and, based on a comparison of the thickness parameters with a predetermined threshold, issue a switching command to the longitudinal and transverse cutting optical system.

[0032] Preferably, the longitudinal and transverse cutting optical system is an electrically controllable optical switch or optical path switcher.

[0033] Preferably, the lens group is a 4f lens system.

[0034] Preferably, the time compression and spatial dispersion system further includes an axial displacement platform, on which the first and second reflectors are mounted.

[0035] Preferably, the time compression and spatial dispersion system also includes a laser focusing system and a third reflecting mirror;

[0036] The third mirror is used to reflect the parallel spectrum emitted from the self-reflecting grating to the laser focusing system.

[0037] Preferably, the adaptive cutting system also includes a thickness measurement sensor for automatically acquiring the thickness parameters of the material to be cut.

[0038] As a further improvement of the present invention, the adaptive cutting system also includes a real-time cutting quality monitoring module, which is connected to the controller signal.

[0039] The controller is also configured as follows:

[0040] Receives monitoring signals reflecting the cutting quality from the real-time cutting quality monitoring module;

[0041] The monitoring signal is compared with a preset quality threshold.

[0042] If the monitored signal is worse than the quality threshold, a dynamic switching command is generated and sent to the longitudinal and transverse cutting optical system.

[0043] Preferably, the real-time cutting quality monitoring module is a spectral monitoring unit, which is integrated into the laser transmission optical path from the femtosecond laser to the material to be cut through a beam splitter, and is used to collect the plasma spectral signal at the processing point.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] This invention utilizes a closed-loop control system of "sensing-judgment-switching," enabling a single system to intelligently select the optimal cutting mode. This overcomes the limitations of narrow processing ranges in single systems, achieving seamless coverage of processing across the entire thickness range from micrometers to centimeters. For thick materials, the long depth of field and non-diffraction characteristics of Bessel beams ensure uniform energy across the entire cutting path, resulting in high perpendicularity, no taper, and resistance to interference from internal material defects due to self-healing properties. For thin materials, spatiotemporal dual-focusing technology reduces the heat-affected zone to the sub-micrometer level, producing smooth, crack-free edges and extremely high cutting precision. Furthermore, "one-click switching" is achieved simply by user input or automatic system acquisition of the material thickness, eliminating the need for equipment replacement or complex optical path readjustment. This significantly reduces equipment and maintenance costs, lowers the technical barrier for operators, and provides an efficient and economical solution for the diversified and large-scale processing of brittle and hard materials.

[0046] Furthermore, this invention introduces real-time quality feedback and dynamic switching, enabling the system to possess "online diagnosis and self-repair" capabilities. It can proactively detect and compensate for microscopic defects such as insufficient cutting depth and microcracks caused by material micro-inhomogeneities, thereby significantly improving the consistency and yield of the entire batch of workpieces. In particular, this capability intelligently addresses the processing challenges of materials with "critical thickness," effectively broadening the stable processing window by dynamically integrating the advantages of two cutting modes. In addition, the real-time acquired physical signals lay a solid foundation for the accumulation of process data and subsequent process optimization. Attached Figure Description

[0047] Figure 1 This is a structural block diagram of the adaptive cutting system in the first embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram of the optical path of the Bessel optical system in the first embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of the optical path of the time compression and spatial dispersion system in the first embodiment of the present invention;

[0050] Figure 4 This is a flowchart of the adaptive cutting method in the first embodiment of the present invention;

[0051] Figure 5 This is a structural block diagram of the adaptive cutting system in the second embodiment of the present invention;

[0052] Figure 6 This is a flowchart of the adaptive cutting method in the second embodiment of the present invention.

[0053] Explanation of the labels in the diagram:

[0054] 1. Femtosecond laser; 2. Bessel optical system; 21. Conical lens; 22. Lens group; 3. Time compression and spatial dispersion system; 31. Laser beam expander; 32. Reflection grating; 33. First mirror; 34. Second mirror; 35. Axial displacement platform; 36. Third mirror; 37. Laser focusing system. Detailed Implementation

[0055] The following detailed description of two embodiments of the present invention, with reference to the accompanying drawings, is provided. It should be noted that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0056] First implementation method:

[0057] Figures 1-3 An adaptive cutting system based on a femtosecond laser is shown, which mainly includes a femtosecond laser 1, a longitudinal and transverse cutting optical system, a Bessel optical system 2, a time compression and spatial dispersion system 3, and a controller.

[0058] The femtosecond laser 1 is used to generate an ultrashort pulse femtosecond laser beam. As a preferred embodiment, a commercially available femtosecond laser with a center wavelength in the infrared band, such as 1030 nm or 1053 nm, and a pulse width on the order of hundreds of femtoseconds can be used.

[0059] To automate the acquisition of thickness parameters, as a preferred embodiment, the adaptive cutting system also includes a thickness measurement sensor. This sensor is preferably a non-contact laser rangefinder or a spectral confocal displacement sensor, mounted near the sample stage with its measuring beam perpendicularly incident on the measurement area of ​​the material to be cut. Before the processing begins or after material change, the controller can drive the sensor or sample stage to perform scanning measurements, thereby automatically and accurately obtaining the material's thickness information. Thickness parameters can also be manually input by the operator through a human-machine interface. The system supports both automatic and manual modes to adapt to different application scenarios.

[0060] The longitudinal and transverse cutting optical system is the core of achieving adaptive switching of the optical path. In a specific embodiment, the system can use a translational mirror assembly driven by a stepper motor or servo motor as an electrically controllable optical switch.

[0061] The controller (which may be integrated into an industrial computer or PLC) is configured to receive the thickness parameter of the material to be cut from a thickness measurement sensor or human-machine interface, and compare the parameter with a built-in predetermined threshold (in this embodiment, the threshold is preferably set to 10 μm). Based on the comparison result, the controller issues a switching command to the longitudinal and transverse cutting optical systems: if the thickness is >10 μm, the drive motor moves the reflector to the first working position corresponding to the Bessel optical system 2, allowing the light beam to enter the Bessel optical system 2; if the thickness is ≤10 μm, it drives the reflector to the second working position corresponding to the time compression and spatial dispersion system 3, allowing the light beam to enter the time compression and spatial dispersion system 3.

[0062] Please see Figure 2 The Bessel optical system 2 includes a conical lens 21 and a lens group 22 arranged sequentially along the optical path. In a preferred embodiment, the lens group 22 is a 4f lens system composed of a first focusing lens and a second focusing lens. The femtosecond laser beam first passes through the conical lens 21, whose unique conical structure converts the incident Gaussian beam into a Bessel beam with a bright central spot and no diffraction characteristics. Subsequently, the Bessel beam undergoes spatial filtering and Fourier transform through the 4f lens system composed of the first and second focusing lenses, thereby achieving precise control over the depth of focus and spot diameter of the Bessel beam. Finally, the long depth of focus Bessel beam is focused into the interior of the material to form a uniform modified layer. By moving the sample stage, the non-diffraction characteristics of this beam can be used to achieve high-quality one-time longitudinal cutting of thick materials, effectively avoiding the problems of cut taper and top overheating.

[0063] Please see Figure 3 The time compression and spatial dispersion system 3 is used to achieve high-precision spatiotemporal focusing and cutting. The system includes a laser beam expander 31, a reflective grating 32, a first reflector 33, a second reflector 34, a third reflector 36, and a laser focusing system 37, which are arranged sequentially along the optical path, a first reflector 33, a second reflector 34, and a third reflector 36, which are arranged perpendicularly to each other and mounted on a high-precision axial displacement platform 35.

[0064] The working principle of the time compression and spatial dispersion system 3 is as follows: The femtosecond laser beam is first expanded by the laser beam expander 31, and then incident on the reflection grating 32. The reflection grating 32 produces different diffraction angles for light of different wavelengths, achieving spatial dispersion and obtaining a spatially separated first spectrum. This first spectrum is reflected by a mirror pair consisting of a first reflecting mirror 33 and a second reflecting mirror 34, returning along the original path to the reflection grating 32 for a second diffraction and collimation, forming a parallel spectrum with different wavelength components propagating in parallel in space.

[0065] To achieve the core effect of "spatiotemporal dual focusing," this system introduces an active dispersion compensation mechanism. By precisely driving the high-precision axial displacement platform 35, the optical path difference between the mirror pair and the reflective grating 32 can be accurately adjusted. This optical path difference is used to introduce a dispersion amount opposite to the negative dispersion introduced by the laser focusing system 37, thereby achieving precise compensation for temporal dispersion and resynchronizing laser components of different wavelengths in time.

[0066] Subsequently, the parallel spectrum, after dispersion compensation, is deflected by the third reflecting mirror 36 and enters the laser focusing system 37 (e.g., a high numerical aperture objective lens), where it is spatiotemporally and dually focused at a predetermined depth within the material. At this focal point, the laser pulse achieves extremely high energy density both spatially and temporally, enabling lateral cutting of the material through nonlinear absorption effects, while causing almost no damage to the material outside the focal point. This reduces the heat-affected zone to the submicron level, resulting in a precise cutting effect with smooth edges and no microcracks.

[0067] The "spatiotemporal dual focusing" in this invention refers to the spatial dispersion achieved through a reflection grating 32 within the time compression and spatial dispersion system 3. A mirror composed of a first reflecting mirror 33 and a second reflecting mirror 34 is used to reflect the laser beam back to the grating for collimation. Simultaneously, the optical path is adjusted via an axial displacement platform 35 to compensate for the temporal dispersion (i.e., group velocity dispersion) generated during the transmission and focusing of the laser pulse. Ultimately, different wavelength components of the laser pulse can simultaneously reach the focal point within the material. This allows for a high concentration of laser energy in both the spatial and temporal dimensions, resulting in an extremely high peak power density at the focal point, achieving efficient and precise cutting.

[0068] Please see Figure 4 Based on the aforementioned adaptive cutting system, an adaptive cutting method based on femtosecond laser includes the following steps: First, the controller receives thickness parameters (automatically acquired or manually input) and compares them with a preset threshold (e.g., 10 μm); then, the controller drives the longitudinal and transverse cutting optical systems to switch optical paths according to the judgment result: if it is a thick material, the Bessel optical system 2 is activated to perform long focal depth longitudinal cutting; if it is a thin material, the time compression and spatial dispersion system 3 is activated to perform spatiotemporal dual focusing transverse cutting.

[0069] Second implementation method:

[0070] This implementation method, based on the first implementation method, introduces a real-time cutting quality monitoring module and dynamic closed-loop control logic, achieving a leap from "static switching based on preset parameters" to "dynamic optimization based on real-time processing quality," aiming to solve microscopic quality defects caused by uneven materials or process fluctuations during the cutting process.

[0071] The system architecture of this embodiment is as follows: Figure 5 As shown, based on all the components of the first embodiment, a real-time cutting quality monitoring module connected to the controller signal is added.

[0072] As a preferred embodiment, the real-time cutting quality monitoring module is a spectral monitoring unit. Specifically, it is seamlessly integrated into the laser transmission optical path from the femtosecond laser 1 to the material to be cut via a beam splitter, enabling its acquisition probe to be precisely aligned with the laser processing point for real-time acquisition of the laser-induced plasma spectral signal generated during the processing.

[0073] The control logic in this implementation constitutes a complete "perception-decision-execution" closed loop. The specific steps are as follows:

[0074] (1) Initial mode selection

[0075] The system first strictly follows the logic of the first implementation: the controller compares the acquired thickness parameters with a predetermined threshold (e.g., 10μm) and selects either the Bezier cutting mode or the spatiotemporal focusing cutting mode as the "main cutting mode" for this cutting task. This mode will be responsible for completing the vast majority of the cutting tasks.

[0076] (2) Real-time quality feedback and dynamic decision-making

[0077] During the cutting process in the "main cutting mode", the real-time cutting quality monitoring module continuously transmits the collected plasma spectral signals to the controller.

[0078] The controller has a pre-stored "quality threshold" corresponding to the "insufficient cutting depth" defect. This threshold is specifically defined as a preset intensity value representing the continuous background spectral intensity of incomplete material vaporization. This threshold can be calibrated through preliminary process experiments. The calibration method includes: cutting a known fully cut sample material under standard process parameters, collecting the continuous background intensity value of its plasma spectrum, and setting this intensity value as the threshold after deducting a certain safety factor.

[0079] If the real-time monitoring signal is better than or equal to the quality threshold, the controller maintains the current main cutting mode.

[0080] If the real-time monitoring signal is worse than the quality threshold (i.e., the continuous background spectral intensity is lower than the preset value), the controller determines that there is a risk of "insufficient cutting depth" and immediately triggers the dynamic switching mechanism.

[0081] (3) Implementation of composite cutting process

[0082] Once the dynamic switching mechanism is triggered, the controller executes the following composite processing technology:

[0083] Instantaneous switching: The controller immediately sends a command to the longitudinal and transverse cutting optical system to temporarily switch the laser beam from the current "main cutting mode" to the "fine cutting mode".

[0084] Refinement Processing: The "Refinement Cutting Mode" utilizes its unique processing advantages to compensate for areas with insufficient cutting depth. As a key optimization, the "Refinement Cutting Mode" and the "Main Cutting Mode" are provided by the Bessel optical system 2 and the time compression and spatial dispersion system 3, respectively. For example:

[0085] Scenario A: When the main cutting mode is Bezier cutting (for thick materials), if the bottom is not cut through, the system switches to spatiotemporal focusing cutting mode. The latter utilizes its extremely high peak power density to "clean" the bottom of the cut, ensuring a complete cut.

[0086] Scenario B: When the main cutting mode is spatiotemporal focusing cutting (for thin materials), if a specific area is detected to require a larger amount of removal, the mode can be temporarily switched to Bezier cutting for rapid etching.

[0087] (4) Judgment of completion of refinement and pattern restoration

[0088] To ensure the integrity and feasibility of the process, this invention explicitly provides specific criteria for determining "refinement completion," the following of which are feasible embodiments:

[0089] Rule 1 (Time-Based Control): Preset a fixed duration (e.g., 5-20 milliseconds) for the finishing process. This duration is determined through process experiments and is sufficient to repair this type of defect. Once the time is up, the controller determines that the finishing process is complete.

[0090] Criterion 2 (Signal Feedback Control): During the finishing process, the plasma spectral signal is continuously monitored. When the signal (such as the continuous background spectral intensity) recovers to a level better than the quality threshold, the controller determines that the defect has been eliminated and the finishing process is complete.

[0091] Criterion 3 (Position-Based Control): Based on the coordinate information of the motion system, a precision repair path is preset for the identified defect area. Once the laser processing head completes the scanning of this path, the precision repair is considered complete.

[0092] The above judgment criteria can be used individually or in combination according to process requirements. When used in combination, priorities can be set, such as determining completion upon meeting any one condition, or requiring multiple conditions to be met simultaneously.

[0093] Once the "fine-tuning is completed" determination is made, the controller immediately instructs the longitudinal and transverse cutting optical systems to switch back to the initial "main cutting mode" and continue to execute subsequent cutting tasks.

[0094] In this invention, the main cutting mode refers to the cutting mode initially selected by the controller based on the comparison between the thickness parameter of the material to be cut and a predetermined threshold (e.g., 10 μm). Specifically, when the thickness is greater than the threshold, the main cutting mode is the Bezier cutting mode; when the thickness is less than or equal to the threshold, the main cutting mode is the spatiotemporal focusing cutting mode. This mode is responsible for completing the vast majority of the cutting tasks. The finishing cutting mode refers to another cutting mode different from the main cutting mode, used to compensate for specific processing defects diagnosed in real time during the main cutting process. For example, when the main cutting mode is the Bezier mode, the finishing cutting mode is the spatiotemporal focusing mode, utilizing its high precision and high peak power characteristics to solve the problem of insufficient cutting depth; when the main cutting mode is the spatiotemporal focusing mode, the finishing cutting mode is the Bezier mode, utilizing its long focal depth and large volume removal characteristics to solve the problem of an excessively large heat-affected zone or the need for rapid etching. Taking the cutting of a sapphire wafer with a thickness of 15 μm as an example, the system first uses the Bezier mode as the main cutting mode. When the continuous background intensity of the plasma spectrum is detected to be below the threshold in real time (indicating that the bottom has not been cut through), the controller switches to spatiotemporal focusing mode for fine-tuning. During the fine-tuning process, the controller continuously monitors the spectral signal. Once the intensity recovers to above the threshold, the fine-tuning is considered complete, and the controller automatically switches back to Bezier mode to continue cutting.

[0095] Accordingly, please refer to Figure 6 The femtosecond laser-based adaptive cutting method in this embodiment further includes the following steps during the cutting process:

[0096] Based on real-time acquired processing quality monitoring signals, dynamic decisions are made and switching is performed between Bezier cutting mode and spatiotemporal focusing cutting mode to compensate for processing defects online.

[0097] In light of current practical needs, the above-described embodiments of this invention are not limited to these specific implementations. Any changes made within the scope of knowledge possessed by those skilled in the art, without departing from the concept of this invention, still fall within the protection scope of this invention.

Claims

1. An adaptive cutting method based on femtosecond laser, characterized in that, Includes the following steps: Obtain the thickness parameters of the material to be cut and compare them with a predetermined threshold. If the thickness parameter is greater than the predetermined threshold, the longitudinal and transverse cutting optical system is controlled to guide the femtosecond laser beam to the Bessel optical system (2); the Bessel optical system (2) uses a conical lens (21) to convert the beam into a Bessel beam and uses a lens group (22) to focus it into the interior of the material for longitudinal cutting; If the thickness parameter is less than or equal to the predetermined threshold, the longitudinal and transverse cutting optical system is controlled to guide the femtosecond laser beam to the time compression and spatial dispersion system (3). The time compression and spatial dispersion system (3) spatially disperses the beam through the reflection grating (32) and uses a pair of mirrors consisting of the first mirror (33) and the second mirror (34) to reflect the dispersed beam back to the reflection grating (32) for collimation. Finally, the collimated parallel spectrum is spatiotemporally double-focused into the interior of the material for transverse cutting.

2. The adaptive cutting method based on femtosecond laser according to claim 1, characterized in that, The predetermined threshold is 10 μm; The lens group (22) is a 4f lens system composed of a first focusing lens and a second focusing lens, used to adjust the depth of focus and spot diameter of the Bessel beam.

3. The adaptive cutting method based on femtosecond laser according to claim 1, characterized in that, In the time compression and spatial dispersion system (3), time dispersion compensation is performed on the collimated parallel spectrum so that the different wavelength components are resynchronized in time; In the time compression and spatial dispersion system (3), the optical path between the first reflector (33) and the second reflector (34) and the reflective grating (32) is adjusted by the drive shaft displacement platform (35) to achieve the time dispersion compensation; The time dispersion compensation is used to enable the laser pulse to achieve spatiotemporal dual focusing during focusing.

4. The adaptive cutting method based on femtosecond laser according to claim 1, characterized in that, The cutting process also includes the following steps: Real-time acquisition of monitoring signals to reflect cutting quality; The monitoring signal is compared with a preset quality threshold. If the monitoring signal is worse than the quality threshold, the longitudinal and transverse cutting optical system is controlled to dynamically switch cutting modes.

5. The adaptive cutting method based on femtosecond laser according to claim 4, characterized in that, The monitoring signal is a laser-induced plasma spectral signal; The monitoring signal being inferior to the quality threshold means that the intensity of the continuous background spectrum representing the incomplete vaporization of the material is lower than a preset intensity threshold. The dynamic switching cutting mode is as follows: temporarily switching from the current main cutting mode to another fine-tuning cutting mode, and then switching back to the main cutting mode after the fine-tuning is completed; The main cutting mode and the fine cutting mode correspond to two different cutting modes provided by the Bessel optical system (2) and the time compression and spatial dispersion system (3), respectively.

6. An adaptive cutting system based on femtosecond laser, used to implement the adaptive cutting method according to any one of claims 1 to 5, characterized in that, include: Femtosecond laser (1); The longitudinal and transverse cutting optical system has its optical path input end connected to the femtosecond laser (1), and its optical path output end can be switched to the Bessel optical system (2) or the time compression and spatial dispersion system (3). The Bessel optical system (2) includes a conical lens (21) and a lens group (22) arranged sequentially along the optical path. The time compression and spatial dispersion system (3) includes a laser beam expander (31) and a reflection grating (32) arranged sequentially along the optical path, as well as a first reflection mirror (33) and a second reflection mirror (34) arranged perpendicularly to each other. The controller, which is signal-connected to the longitudinal and transverse cutting optical system, is configured to: receive the thickness parameter and, based on the comparison result of the thickness parameter and a predetermined threshold, issue a switching command to the longitudinal and transverse cutting optical system.

7. The adaptive cutting system based on femtosecond laser according to claim 6, characterized in that, The longitudinal and transverse cutting optical system is an electrically controllable optical switch or optical path switcher, and the lens group (22) is a 4f lens system.

8. The adaptive cutting system based on femtosecond laser according to claim 6, characterized in that, The time compression and spatial dispersion system (3) also includes an axial displacement platform (35), a laser focusing system (37), and a third reflecting mirror (36). The first reflector (33) and the second reflector (34) are mounted on the axial displacement platform (35); The third mirror (36) is used to reflect the parallel spectrum emitted from the reflection grating (32) to the laser focusing system (37). The adaptive cutting system also includes a thickness measurement sensor for automatically acquiring the thickness parameters of the material to be cut.

9. The adaptive cutting system based on femtosecond laser according to claim 6, characterized in that, The adaptive cutting system also includes a real-time cutting quality monitoring module, which is connected to the controller signal. The controller is also configured to: Receives monitoring signals reflecting the cutting quality from the real-time cutting quality monitoring module; The monitoring signal is compared with a preset quality threshold. If the monitoring signal is inferior to the quality threshold, a dynamic switching command is generated and sent to the longitudinal and transverse cutting optical system.

10. The adaptive cutting system based on femtosecond laser according to claim 9, characterized in that, The real-time cutting quality monitoring module is a spectral monitoring unit, which is integrated into the laser transmission optical path from the femtosecond laser (1) to the material to be cut through a beam splitter, and is used to collect the plasma spectral signal at the processing point.

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