Ultrafast laser processing system and control method thereof

Abstract

The invention relates to the technical field of laser processing, in particular to an ultrafast laser processing system and a control method thereof. According to the technical scheme, the ultrafast laser processing system is constructed based on a laser device, an acousto-optic deflection assembly, a galvanometer assembly, a field lens and a controller. The laser device is used for transmitting a laser beam with the pulse width lower than the picosecond magnitude during a processing task. The acousto-optic deflection assembly is used for executing processing path modulation of a laser beam in a first mode and outputting the modulated laser beam through the field lens; the galvanometer assembly is used for jointly executing processing path modulation of the laser beams in the second mode based on the acousto-optic deflection assembly and outputting the modulated laser beams through the field lens. According to the scheme, the machining system can be controlled to enter different modes, the response delay of the galvanometer assembly executing machining path modulation is compensated through the acousto-optic deflection assembly, the machining path modulation of the laser beam meets the corresponding requirements of precision and efficiency, and the local ablation defect caused by ultrafast laser in the machining process is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing, and in particular to an ultrafast laser processing system and a control method thereof. Background Art

[0002] In the field of laser processing, ultrafast lasers have pulse widths below picoseconds (10 -12 Ultrafast lasers have the advantages of short pulses and small thermal effects in "cold processing". In order to further reduce the cumulative thermal effect, ultrafast lasers need to have faster scanning speeds. For example, when processing some polymer films for electronic devices, even if the thermal effect of the ultrafast laser itself is relatively small, if the scanning speed is too slow, heat will still accumulate in local areas, which may cause material deformation, performance degradation and other problems. In order to maintain the stability of material performance, a faster scanning speed is required to quickly complete the processing process.

[0003] Currently, ultrafast lasers face some technical challenges when applied to processing. Traditional laser processing systems have limitations in optical path modulation. Although a single galvanometer modulation method can achieve a large range of scanning, it has a response hysteresis problem. This response hysteresis will lead to a decrease in the accuracy of ultrafast laser processing, especially in the field of micro-nano processing, which requires extremely high processing accuracy. The response hysteresis will cause local ablation, making the processed parts fail to meet quality requirements.

[0004] Therefore, how to reduce the local ablation defects caused by ultrafast laser during the processing is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to provide an ultrafast laser processing system and a control method thereof, so that the processing path modulation of the ultrafast laser takes into account both the modulation accuracy and the modulation efficiency, thereby reducing the local ablation defects caused by the ultrafast laser during the processing. The technical solutions adopted are as follows: In a first aspect, an embodiment of the present invention provides an ultrafast laser processing system, the system comprising: Lasers, used to emit laser beams with pulse widths below picoseconds for processing tasks; an acousto-optic deflection assembly, arranged adjacent to the laser; the acousto-optic deflection assembly is used to perform processing path modulation of the laser beam in a first mode, and output the modulated laser beam to the outside through a field mirror; The galvanometer assembly is arranged adjacent to the acousto-optic deflection assembly; the galvanometer assembly is used to perform processing path modulation of the laser beam based on the acousto-optic deflection assembly in the second mode, and output the modulated laser beam to the outside through the field mirror; A controller is connected to the laser, the acousto-optic deflection assembly and the galvanometer assembly. The controller is used to control the acousto-optic deflection assembly to enter a first mode when the optical path modulation range of the processing task is within a first maximum range of the acousto-optic deflection assembly; and to control the acousto-optic deflection assembly and the galvanometer assembly to enter a second mode when the optical path modulation range is greater than the first maximum range and is within a second maximum range of the galvanometer assembly, so as to compensate for the response hysteresis of the galvanometer assembly in performing processing path modulation via the acousto-optic deflection assembly.

[0006] In an optional embodiment, the system further includes: Gantry, the crossbeam of the gantry is used to install the laser, the acousto-optic deflection assembly, the galvanometer assembly and the field mirror; A driving component is installed on the gantry, and a driving port of the driving component is connected to the controller; the driving component is used to drive the X-axis and Y-axis movement of the gantry based on the controller, so that the processing range of the laser beam is larger than the second maximum range; The controller is also used to control the acousto-optic deflection assembly and / or the galvanometer assembly to perform movement backlash compensation of the driving assembly when the driving assembly responds to a processing task greater than a second maximum range.

[0007] In an optional embodiment, the acousto-optic deflection assembly includes: an X-direction acousto-optic deflector for performing response hysteresis compensation on the X-direction galvanometer of the galvanometer assembly in the second mode; The Y-direction acousto-optic deflector is used to perform response hysteresis compensation on the Y-direction galvanometer of the galvanometer assembly in the second mode.

[0008] In an optional embodiment, the system further includes: The zoom component is arranged between the galvanometer component and the field lens. The control port of the zoom component is connected to the controller. The zoom component is used to perform zoom modulation of the laser beam based on the controller when the laser beam has a focal length deviation in the second mode.

[0009] In a second aspect, an embodiment of the present invention further provides an ultrafast laser processing system control method, which is applied to any processing system in the first aspect, wherein the processing system includes a laser, an acousto-optic deflection assembly, a galvanometer assembly, and a field mirror arranged in sequence along the optical path direction; the method includes: In the processing task, the laser is controlled to emit a laser beam with a pulse width less than picoseconds; When the optical path modulation range of the processing task is within the first maximum range of the acousto-optic deflection assembly, the acousto-optic deflection assembly is controlled to perform processing path modulation of the laser beam in the first mode, and the modulated laser beam is output to the outside through the field lens; When the optical path modulation range is greater than the first maximum range and is within the second maximum range of the galvanometer assembly, the acousto-optic deflection assembly and the galvanometer assembly are controlled to jointly perform processing path modulation of the laser beam in the second mode, and the modulated laser beam is output to the outside through the field lens to compensate for the response lag of the galvanometer assembly in performing processing path modulation through the acousto-optic deflection assembly.

[0010] In an optional embodiment, before controlling the acousto-optic deflection assembly and the galvanometer assembly to jointly perform processing path modulation of the laser beam in the second mode, the method further includes: Determine whether there is a target working condition for the processing task, wherein the target working condition is the start-up working condition of the galvanometer component, or the curvature change of the task curve of the processing task of the galvanometer component is greater than a preset threshold, or the angle between adjacent line segments of the processing task of the galvanometer component is within a preset range; If so, an admission instruction for the second mode is output.

[0011] In an optional embodiment, the processing system further includes a gantry, and the crossbeam of the gantry is used to install the laser, the acousto-optic deflection assembly, the galvanometer assembly and the field mirror; the method further includes: When the driving component installed on the gantry responds to a processing task greater than the second maximum range, the acousto-optic deflection component and / or the galvanometer component is controlled to perform reverse clearance compensation of the driving component; wherein the driving component is used to drive the X-axis and Y-axis movement of the gantry based on the controller so that the processing range of the laser beam is greater than the second maximum range.

[0012] In an optional embodiment, controlling the acousto-optic deflection assembly and / or the galvanometer assembly to perform movement backlash compensation of the driving assembly includes: Determine a reverse compensation curve of the driving component according to the driving parameters corresponding to the driving component when performing the processing task, wherein the reverse compensation curve is a curve showing the reverse compensation amount changing with the compensation time; Dividing the reverse compensation curve into a first curve segment, a second curve segment and a third curve segment along its compensation time; Controlling the acousto-optic deflection assembly and the galvanometer assembly to perform movement reverse gap compensation of the driving assembly according to the first curve segment; Controlling the galvanometer assembly to perform movement reverse gap compensation of the driving assembly according to the second curve segment; The acousto-optic deflection assembly is controlled according to the third curve segment to perform movement reverse gap compensation of the driving assembly.

[0013] In an optional embodiment, controlling the acousto-optic deflection assembly and the galvanometer assembly to jointly perform processing path modulation of the laser beam in the second mode includes: A compensation relationship is established between the X-direction acousto-optic deflector and the Y-direction acousto-optic deflector of the acousto-optic deflection assembly and the X-direction galvanometer and the Y-direction galvanometer of the galvanometer assembly respectively; In the second mode, an actual deflection curve and a theoretical deflection curve corresponding to each galvanometer in the galvanometer assembly when performing a processing task are determined, wherein the actual deflection curve is a curve showing that the actual deflection angle of the galvanometer changes with the deflection time, and the theoretical deflection curve is a curve showing that the theoretical deflection angle of the galvanometer changes with the deflection time; According to the difference between the actual deflection curve of each galvanometer and the theoretical deflection curve, a compensation curve of the corresponding galvanometer is obtained; According to the compensation curve and the compensation relationship, the X-direction acousto-optic deflector and the Y-direction acousto-optic deflector are controlled to perform response delay compensation.

[0014] In an optional embodiment, the method further includes: In the second mode, it is determined whether the laser beam in the processing task has a focus deviation; If so, the zoom assembly disposed between the galvanometer assembly and the field lens is controlled to perform zoom modulation of the laser beam.

[0015] The present invention has the following beneficial effects: The technical solution of the present invention is based on a laser, an acousto-optic deflection assembly, a galvanometer assembly, a field mirror and a controller to construct an ultrafast laser processing system. When the optical path modulation range of the processing task is within the first maximum range of the acousto-optic deflection assembly, the controller controls the acousto-optic deflection assembly to enter a first mode, and the acousto-optic deflection assembly modulates the processing path of the laser beam based on the acousto-optic effect, so that the processing path modulation of the laser beam meets the corresponding requirements of accuracy and efficiency; when the optical path modulation range is greater than the first maximum range and is within the second maximum range of the galvanometer assembly, the acousto-optic deflection assembly and the galvanometer assembly are controlled to enter a second mode to perform processing path modulation of the laser beam. In the second mode, the acousto-optic deflection assembly and the galvanometer assembly jointly implement the processing path modulation of the laser beam, and the acousto-optic deflection assembly compensates for the response hysteresis of the galvanometer assembly in performing the processing path modulation, so that the processing path modulation of the laser beam can also meet the corresponding requirements of accuracy and efficiency, and the heat generated by the ultrafast laser will not be focused on the local area of ​​the processing component, thereby reducing the local ablation defects caused by the ultrafast laser during the processing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of electrical connections of an ultrafast laser processing system provided by one embodiment of the present invention; Figure 2A schematic diagram of the installation structure of an ultrafast laser processing system provided by one embodiment of the present invention; Figure 3 A flowchart of an ultrafast laser processing system control method provided by one embodiment of the present invention; Figure 4 A schematic diagram of the principle of mobile reverse clearance compensation provided by an embodiment of the present invention.

[0018] Description of reference numerals: 1-laser, 2-acoustic-optical deflection assembly, 3-galvanometer assembly, 4-field mirror, 5-gantry, 6-driving assembly, 7-zoom assembly; 21-X-direction acousto-optic deflector, 22-Y-direction acousto-optic deflector; 31-X-axis galvanometer, 32-Y-axis galvanometer; 51-crossbeam, 52-fixed plate, 53-X axis, 54-Y axis; 61 - first drive motor, 62 - second drive motor. DETAILED DESCRIPTION

[0019] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of an ultrafast laser processing system and its control method proposed by the present invention, its specific implementation, structure, features and effects, in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0020] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0021] The specific scheme of an ultrafast laser processing system and a control method thereof provided by the present invention is described in detail below with reference to the accompanying drawings.

[0022] See also Figure 1 , Figure 1 A schematic diagram of the structure of an ultrafast laser processing system provided by an embodiment of the present invention, the ultrafast laser processing system includes a laser 1, an acousto-optic deflection assembly 2, a galvanometer assembly 3, a field mirror 4 and a controller (not shown in the figure). The controller is connected to the laser 1, the acousto-optic deflection assembly 2 and the galvanometer assembly 3, and can implement the control of the laser, the acousto-optic deflection assembly and the galvanometer assembly under the same clock based on the crystal oscillator configured on the controller to improve the control accuracy. Figure 1The dotted line indicated by the middle arrow is a schematic diagram of the propagation direction of the laser beam. The laser beam emitted by the laser passes through the acousto-optic deflection assembly, the galvanometer assembly and the field mirror in sequence to be output to the processing component for processing. The processing component can be a metal material, such as an iron plate, a stainless steel plate, etc. Based on the processing system, the metal material can be cut, marked, marked, etc.; it can also be a non-metallic material, such as drilling and cutting ceramic materials for high-end packaging, especially for micro-hole processing of ceramic materials with high processing efficiency and good accuracy.

[0023] It can be understood that when the ultrafast laser processing system of the embodiment of the present invention is applied to the processing of high molecular polymer films of electronic devices, since the thermal effect of the ultrafast laser itself is small and the processing system can achieve a faster scanning speed, heat will not accumulate locally during the processing due to the response hysteresis of the galvanometer, so it can effectively reduce local ablation during the processing, will not cause processing deformation of such materials, and can maintain the stability of the high molecular polymer film during ultrafast laser cutting. The technical solution adopted by the processing system will be specifically described below.

[0024] The laser of the processing system can be selected based on the actual application. For example, the output power and wavelength of the laser can be determined based on the type of processing parts. The laser is used to emit a laser beam with a pulse width of less than picoseconds in the processing task, that is, an ultrafast laser. Ultrafast lasers have unique application advantages. Their extremely short pulse width enables the energy to be released in a very short time when acting on the processing parts. Compared with traditional long-pulse lasers, it can complete the processing process before the processing parts have time to diffuse the absorbed energy to the surrounding area through heat conduction. This feature greatly reduces the scope of the heat-affected zone and reduces the problems of material deformation and microcracks caused by thermal effects during the processing process, thereby significantly improving the processing accuracy and surface quality. It is especially suitable for high-end manufacturing fields that have strict requirements on processing accuracy and material integrity, such as aerospace precision parts processing, high-end electronic product manufacturing, etc.

[0025] The acousto-optic deflection assembly is arranged adjacent to the laser; this layout is conducive to the laser beam being able to quickly and efficiently enter the acousto-optic deflection assembly for subsequent processing after it is generated, reducing the energy loss and optical path deviation risk during the transmission of the laser beam, and ensuring the stability and accuracy of the system operation. The acousto-optic deflection assembly is used to perform processing path modulation of the laser beam in the first mode, and output the modulated laser beam to the outside through the field mirror. The first mode is the optical path modulation mode implemented when the optical path modulation range of the processing task is within the first maximum range of the acousto-optic deflection assembly. The acousto-optic deflection assembly uses the principle of the acousto-optic effect and the interaction between sound waves and lasers in a specific medium to change the propagation direction and phase and other characteristics of the laser beam, thereby achieving precise control of the laser beam processing path. For example, in some complex shape processing tasks, such as special-shaped cutting of precision parts or engraving of complex patterns, the path modulation of the acousto-optic deflection assembly can make the laser beam move along a preset trajectory to ensure processing accuracy and shape accuracy.

[0026] It should be noted that the field lens can optimize the focusing characteristics of the laser beam and adjust the beam distribution. It can focus the modulated laser beam to the processing area and adjust the parameters such as the size, shape and uniformity of the light spot according to the processing requirements. For example, in the field of micro-processing, the field lens can focus the laser beam into a very small light spot and increase the energy density of the laser to perform fine processing on tiny parts; in large-area processing scenarios, the field lens can appropriately expand and homogenize the laser beam to ensure the consistency of the processing effect in the processing area.

[0027] The galvanometer assembly is arranged adjacent to the acousto-optic deflection assembly; the galvanometer assembly is used to perform processing path modulation of the laser beam based on the acousto-optic deflection assembly in the second mode, and output the modulated laser beam to the outside through the field mirror. The galvanometer assembly is usually driven by a motor to rotate the reflector. Due to the structure of the galvanometer assembly, when it is controlled, the motor's own rotational inertia will prevent it from responding immediately after receiving a signal to change the rotation speed or direction, causing the galvanometer assembly to have a response lag when performing processing path modulation alone.

[0028] The controller can be a PLC (Programmable Logic Controller), or an industrial computer or an embedded control terminal, and is not specifically limited here. The controller is used to control the acousto-optic deflection assembly to enter the first mode when the optical path modulation range of the processing task is within the first maximum range of the acousto-optic deflection assembly. In the first mode, the acousto-optic deflection assembly can realize rapid optical path modulation of the laser beam through the acousto-optic effect, and the spot of the laser beam irradiated to the processing component will not generate excessive local heat, thereby reducing local ablation defects of the processing component. When the optical path modulation range is greater than the first maximum range and is within the second maximum range of the galvanometer assembly, a large range of optical path modulation cannot be achieved through a single acousto-optic deflection assembly, so the acousto-optic deflection assembly and the galvanometer assembly are controlled to enter the second mode to compensate for the response hysteresis of the galvanometer assembly in performing processing path modulation through the acousto-optic deflection assembly. The acousto-optic deflection assembly uses the acousto-optic effect to change the laser propagation path. By adjusting the acoustic wave parameters, the transmission direction of the laser beam can be quickly changed to compensate for the path deviation caused by the response hysteresis of the galvanometer assembly, so that the processing path modulation is more accurate, and the processing accuracy and quality of ultrafast lasers are improved.

[0029] For example, see Figure 2 , Figure 2 The main view of the processing system is shown in FIG. 2 . The acousto-optic deflection assembly 2 includes an X-axis acousto-optic deflector 21 and a Y-axis acousto-optic deflector 22. The galvanometer assembly 3 includes an X-axis galvanometer 31 and a Y-axis galvanometer 32. The laser beam emitted by the laser is Figure 2 As indicated by the dotted arrows, the laser beam sequentially passes through the X-direction acousto-optic deflector 21, the Y-direction acousto-optic deflector 22, the X-direction galvanometer 31, and the Y-direction galvanometer 32. In the first mode, since the optical path modulation range of the processing task is within the first maximum range of the acousto-optic deflection assembly, the X-direction galvanometer and the Y-direction galvanometer stop working, and the optical path modulation of the laser beam is implemented by the X-direction acousto-optic deflector and the Y-direction acousto-optic deflector.

[0030] In the second mode, the optical path modulation range of the processing task is large, and a large range of optical path modulation cannot be achieved through the X-direction acousto-optic deflector and the Y-direction acousto-optic deflector. Therefore, it is necessary to implement optical path modulation through the X-direction galvanometer and the Y-direction galvanometer. In order to reduce the local overheating of the processing parts caused by the galvanometer response hysteresis, the X-direction acousto-optic deflector is used to perform response hysteresis compensation on the X-direction galvanometer of the galvanometer assembly, and the Y-direction acousto-optic deflector is used to perform response hysteresis compensation on the Y-direction galvanometer of the galvanometer assembly. By using the X-direction acousto-optic deflector and the Y-direction acousto-optic deflector, respectively, the response hysteresis compensation is implemented on the X-direction galvanometer and the Y-direction galvanometer, which can effectively improve the accuracy of control and simplify the control strategy.

[0031] In practical applications, due to the small processing range and angle restrictions of the laser beam optical path modulation based on the galvanometer, the laser processing system has limited processing range. Based on this, in a specific implementation, the processing system also includes a gantry and a drive assembly.

[0032] Please continue reading Figure 2 The gantry 5 is mounted on the laser processing equipment carried by the processing system, and a fixing plate 52 is arranged on the crossbeam 51 of the gantry 5, and the laser 1, the acousto-optic deflection assembly 2, the galvanometer assembly 3 and the field mirror 4 are installed based on the fixing plate 52.

[0033] The driving assembly 6 is mounted on the gantry 5, and the driving port of the driving assembly 6 is connected to the controller; the driving assembly 6 is used to drive the X-axis 53 and the Y-axis 54 of the gantry 5 to move based on the controller, so that the processing range of the laser beam is greater than the second maximum range; the controller is also used to control the acousto-optic deflection assembly and / or the galvanometer assembly to perform the movement backlash compensation of the driving assembly when the driving assembly responds to a processing task greater than the second maximum range. The driving assembly 6 includes a first driving motor 61 and a second driving motor 62, the first driving motor 61 is used to drive the X-axis 53 of the gantry 5 to move, and the second driving motor 62 is used to drive the Y-axis 54 of the gantry 5 to move.

[0034] Furthermore, in the second mode, the acousto-optic deflection assembly needs to implement response hysteresis compensation for the galvanometer assembly. The change in the direction of the light during the compensation process will affect the focusing position of the laser beam in the optical system. For example, during the operation of the acousto-optic deflector, the ultrasonic waves generated inside will cause periodic changes in the refractive index of the medium, thereby causing the diffraction of the laser beam. In addition to changing the direction of the laser beam, this diffraction phenomenon will also change the wavefront of the laser beam. The change in the wavefront will affect the subsequent focusing process, because focusing elements such as field lenses are designed to focus based on a specific wavefront shape. When the acousto-optic deflector causes the wavefront of the laser beam to change, it cannot be accurately focused according to the original design when it is focused by the field lens, resulting in a deviation in the focal length of the laser beam, which in turn affects the processing quality of the laser beam.

[0035] Based on this, the processing system also includes a zoom component 7, which can be configured as a mechanical zoom lens, and the zoom lens contains movable optical elements such as a lens group. When zooming is required, the motor drives the lens group to move along the optical axis, that is, Figure 2The laser beam moves in the Z-axis direction shown in . The focal length of the laser beam can be adjusted by the zoom assembly so that it is focused on the processing part. The zoom assembly is arranged between the galvanometer assembly and the field lens. The control port of the zoom assembly is connected to the controller. The zoom assembly is used to perform zoom modulation of the laser beam based on the controller when the laser beam has a focal length deviation in the second mode. When the zoom modulation of the laser beam is implemented based on the zoom assembly, the focal length change corresponding to the compensation implemented by the acousto-optic deflection assembly can be determined through a calibration experiment. The controller implements corresponding control of the zoom assembly based on the focal length change so that the laser beam is focused on the processing part.

[0036] In order to further improve the processing quality of ultrafast lasers, a collimator can be set between the galvanometer assembly and the zoom assembly to collimate and calibrate the laser beam. The collimator can make the wavefront of the laser beam flatter and enter the zoom assembly in a more regular manner. After the laser beam passes through the collimator, its wavefront curvature decreases and becomes closer to a plane wave. In this way, when passing through the zoom assembly, the aberration caused by the irregular wavefront can be reduced, thereby improving the imaging quality and beam focusing accuracy of the laser beam in the entire optical system, which helps to improve the processing accuracy and quality of ultrafast lasers.

[0037] Based on the same technical concept as the processing system, the embodiment of the present invention also provides an ultrafast laser processing system control method, which is applied to the above ultrafast laser processing system. The processing system includes a laser, an acousto-optic deflection assembly, a galvanometer assembly and a field mirror arranged in sequence along the optical path direction. The laser, the acousto-optic deflection assembly and the galvanometer assembly are all connected to a preset controller. Figure 3 , Figure 3 is a flow chart of a control method, which can be applied to the controller operation of a processing system, and the control method includes: S11. In the processing task, the laser is controlled to emit a laser beam with a pulse width less than picoseconds.

[0038] Specifically, the execution instruction of the processing task is based on the user's issuance. When the controller receives the execution instruction of the processing task, it indicates that the processing part needs to be processed, and then controls the laser to output an ultrafast laser beam. The wavelength, pulse width, pulse energy, and spot size of the laser beam can be configured based on the actual processing requirements, and can meet the actual processing requirements of the processing parts.

[0039] S12, when the optical path modulation range of the processing task is within the first maximum range of the acousto-optic deflection assembly, controlling the acousto-optic deflection assembly to perform processing path modulation of the laser beam in the first mode, and outputting the modulated laser beam to the outside through the field lens.

[0040] Specifically, the first maximum range is the range within which the acousto-optic deflection assembly can control the deflection of the laser beam based on the acousto-optic effect. When the optical path modulation range is within the first maximum range, it means that the processing path modulation of the laser beam can be controlled to meet the requirements in the processing task by controlling the acousto-optic deflection assembly, and the processing system is controlled to enter the first mode to implement the processing path modulation of the laser beam. In the first mode, the galvanometer assembly does not deflect, and the galvanometer assembly can be controlled to stop at a preset initial position, or it can stop at a preset target position based on the optical path modulation requirements. After being modulated by the acousto-optic deflection assembly, the laser beam is reflected to the field mirror by the galvanometer assembly, and then emitted to the processing component after being focused by the field mirror. In the first mode, the laser beam has a faster scanning speed through the modulation of the acousto-optic deflection assembly. Since the thermal effect of the ultrafast laser itself is small, local ablation of the processing component will not occur.

[0041] S13. When the optical path modulation range is greater than the first maximum range and is within the second maximum range of the galvanometer assembly, the acousto-optic deflection assembly and the galvanometer assembly are controlled to jointly perform processing path modulation of the laser beam in the second mode, and the modulated laser beam is output to the outside through the field lens to compensate for the response lag of the galvanometer assembly in performing processing path modulation through the acousto-optic deflection assembly.

[0042] Specifically, in the second mode, the acousto-optic deflection assembly and the galvanometer assembly work together to modulate the processing path of the laser beam. The galvanometer assembly has a response hysteresis problem when modulating the processing path, while the acousto-optic deflection assembly has a fast response speed. The acousto-optic deflection assembly can make up for this deficiency of the galvanometer assembly. After the two work together, the precisely modulated laser beam is output through the field mirror, thereby ensuring the accuracy and efficiency of the optical path modulation during the laser processing process, so as to reduce local ablation of the processing parts, meet the processing requirements and improve the processing quality and precision. It can be understood that after the response hysteresis compensation of the galvanometer assembly based on the acousto-optic deflection assembly, the local ablation defects on the processing parts can be basically eliminated.

[0043] It should be noted that each processing task can be decomposed based on the processing path of the processing part. For example, when the processing part needs to cut the outer shape and multiple inner holes, the curve of each inner hole is treated as a separate processing task. Inner hole processing and outer shape processing have different requirements in many aspects. From the perspective of processing accuracy, the inner hole requires higher accuracy to ensure dimensional tolerance and surface quality. Treating it as a separate processing task is convenient for setting special processing parameters for it, such as adjusting the appropriate laser power, pulse frequency and cutting speed during laser cutting. Usually, the inner hole processing is carried out first, and then the outer shape cutting is carried out. Taking each inner hole curve as an independent processing task is more convenient in programming control, and the processing process of each inner hole can be monitored and adjusted separately, which is conducive to ensuring the processing quality of ultrafast laser.

[0044] Exemplarily, step S13 includes sub-steps S13-1 to S13-4, which are specifically described as follows: S13-1. The X-direction acousto-optic deflector and the Y-direction acousto-optic deflector of the acousto-optic deflection assembly are respectively connected to the X-direction galvanometer and the Y-direction galvanometer of the galvanometer assembly to establish a compensation relationship. The X-direction acousto-optic deflector is used to compensate for the response hysteresis of the X-direction galvanometer, and the Y-direction acousto-optic deflector is used to compensate for the response hysteresis of the Y-direction galvanometer. When debugging the laser cutting equipment, the compensation relationship between the X-direction acousto-optic deflector and the X-direction galvanometer can be tested and adjusted separately. After determining the optimal parameters, the same operation can be performed on the Y-direction acousto-optic deflector and the Y-direction galvanometer. In this way, the entire processing system can be optimized more systematically and the equipment performance can be improved.

[0045] S13-2. In the second mode, the actual deflection curve and theoretical deflection curve corresponding to each galvanometer in the galvanometer assembly when performing a processing task are determined. The actual deflection curve and theoretical deflection curve can be obtained through calibration tests or simulation experiments. The actual deflection curve is a curve showing the actual deflection angle of the galvanometer changing with the deflection time. The actual deflection curve describes the control change result of the galvanometer during the actual working process. It records how the actual deflection angle of the galvanometer changes with time. This curve reflects the actual motion state of the galvanometer under the influence of various actual factors, including the friction of mechanical parts, the actual driving performance of the motor, the real-time response characteristics of the control system, and external environmental interference (such as vibration, temperature changes, etc.). For example, in the laser processing process, due to the possible wear of the mechanical transmission parts of the galvanometer, or the speed fluctuation of the motor under different loads, the actual deflection angle of the galvanometer will deviate from the ideal state, and the actual deflection curve can reflect these situations truthfully. The theoretical deflection curve is a curve showing the change of the theoretical deflection angle of the galvanometer with the deflection time. The theoretical deflection curve is a curve constructed based on the physical model, control algorithm and equipment performance parameters. This curve has estimated deviations under adverse factors such as mechanical loss, electrical interference and control delay of the galvanometer. It is based on the relationship between the galvanometer deflection angle and deflection time under ideal control conditions.

[0046] S13-3, according to the difference between the actual deflection curve and the theoretical deflection curve of each galvanometer, obtain the compensation curve of the corresponding galvanometer. The actual deflection curve and the theoretical deflection curve can be compared on the same time axis, and the time can be divided into a series of time points with equal intervals. At each time point, the difference between the theoretical deflection angle and the actual deflection angle is calculated, and a compensation curve is constructed based on all the obtained differences. The compensation curve is a curve of the angle deviation of the galvanometer changing with the deflection time.

[0047] S13-4, according to the compensation curve and the compensation relationship, the X-direction acousto-optic deflector and the Y-direction acousto-optic deflector are controlled to perform response hysteresis compensation. The compensation curve includes a first curve for compensating the X-direction galvanometer and a second curve for compensating the Y-direction galvanometer. Each compensation curve characterizes the corresponding change relationship between the angle deviation of the corresponding galvanometer and the deflection time. Based on the compensation relationship, the acousto-optic deflector corresponding to each galvanometer when the compensation is implemented can be determined, so that the X-direction acousto-optic deflector and the Y-direction acousto-optic deflector can be controlled based on the compensation curve to perform response hysteresis compensation of the corresponding galvanometer.

[0048] Furthermore, before executing step S13, the control method further includes: Determine whether there is a target working condition for the processing task. The target working condition is the working condition where the galvanometer will cause local ablation of the processing parts due to its response hysteresis. For example, in the startup working condition of the galvanometer component, there is a certain time delay in the startup process of the motor. Since the motor winding needs to establish a magnetic field and overcome its own inertia to start rotating, the motor cannot reach the target speed immediately at the moment of startup, so that the angle change of the galvanometer cannot keep up with the requirements of the control signal, resulting in response hysteresis. The curvature change of the task curve of the processing task of the galvanometer component is greater than the preset threshold, which means that the galvanometer needs to quickly change the deflection angle in a short time. The galvanometer itself has a certain mass, and the inertia of the galvanometer will hinder its rapid change of angle, resulting in a certain torque and time required to change its motion state, resulting in response hysteresis. Similarly, the angle between adjacent line segments of the processing task of the galvanometer component is within the preset range. The galvanometer also needs to achieve a large angle change in a short time. The rotational inertia of the motor will affect the real-time response of the galvanometer, which will also cause the galvanometer to have a response hysteresis.

[0049] When it is determined that the processing task has a target working condition, the second mode entry instruction is output to control the acousto-optic deflection component and the galvanometer component to jointly implement the processing path modulation of the laser beam. Conversely, when the target working condition does not exist in the processing task, the second mode entry prohibition instruction is output to implement the processing path modulation of the laser beam based on the galvanometer component.

[0050] In order to reduce the limitation of the laser processing system in implementing the processing, in a specific implementation, the processing system further includes a gantry, and the crossbeam of the gantry is used to install the laser, the acousto-optic deflection assembly, the galvanometer assembly and the field mirror; the control method also includes: S14. When the driving component installed on the gantry responds to a processing task greater than the second maximum range, the acousto-optic deflection component and / or the galvanometer component are controlled to perform reverse clearance compensation of the driving component; wherein the driving component is used to drive the X-axis and Y-axis movement of the gantry based on the controller so that the processing range of the laser beam is greater than the second maximum range.

[0051] Specifically, the driving assembly includes a first driving motor and a second driving motor, the first driving motor is used to drive the X-axis movement of the gantry, and the second driving motor is used to drive the Y-axis movement of the gantry. When the optical path modulation range of the processing task is greater than the second maximum range, it means that the optical path modulation of the laser beam implemented by the galvanometer assembly cannot reach the optical path modulation range of the processing task, and the processing task greater than the second maximum range is performed by the driving assembly. Since the driving structure of the gantry is a ball screw structure, it has a reverse gap, which can be compensated by the first driving motor and the second driving motor, but there is also a problem of response hysteresis, which will cause local ablation defects on the processing parts. The acousto-optic deflection assembly and the galvanometer assembly have the advantage of rapid modulation of the optical path, so controlling the acousto-optic deflection assembly and / or the galvanometer assembly to perform the reverse gap compensation of the driving assembly can effectively reduce the local ablation on the processing parts.

[0052] It can be understood that when performing mobile reverse clearance compensation based on the acousto-optic deflection assembly and the galvanometer assembly, the X-axis of the gantry can be compensated for mobile reverse clearance based on the X-axis acousto-optic deflector and the X-axis galvanometer. For example, when the compensation amount is less than the compensation amount threshold, it means that the compensation amount is small, and the X-axis acousto-optic deflector is used to implement compensation; when the compensation amount is greater than or equal to the compensation amount threshold, the X-axis galvanometer is used to implement compensation; if the X-axis galvanometer has the above-mentioned target working condition, the response hysteresis compensation of the X-axis galvanometer is performed based on the X-axis acousto-optic deflector. Similarly, based on the Y-axis acousto-optic deflector and the Y-axis galvanometer, the Y-axis of the gantry is compensated for mobile reverse clearance. The specific implementation method is the same as that of the X-axis, and will not be further described here.

[0053] Exemplarily, step S14 includes sub-steps S14-1 to S14-5, which are specifically described as follows: S14-1. Determine the reverse compensation curve of the drive component according to the drive parameters corresponding to the drive component when performing the processing task, wherein the reverse compensation curve is a curve of the reverse compensation amount changing with the compensation time. The drive parameters include drive speed, acceleration, torque, etc. By analyzing and processing these drive parameters, the reverse compensation curve of the drive component can be determined. Different processing tasks will cause the drive component to be in different motion states, and these motion states will affect the size of the reverse gap. The reverse compensation curve uses the reverse compensation amount as the ordinate and the compensation time as the abscissa, which intuitively shows how the reverse compensation amount to be applied changes over time during the entire compensation process. For example, in laser cutting processing, when the first drive motor in the drive component switches forward and reverse, a reverse gap will be generated due to factors such as the mechanical structure. At this time, the reverse compensation curve is determined according to the drive parameters such as the speed and acceleration of the first drive motor, so that it is known how much displacement needs to be compensated at different times, thereby obtaining the corresponding reverse compensation curve.

[0054] S14-2, divide the reverse compensation curve into the first curve segment, the second curve segment and the third curve segment along its compensation time. Divide the reverse compensation curve into three curve segments along its compensation time. This segmentation helps to implement reverse clearance compensation more finely according to the characteristics of different stages. Different curve segments correspond to different stages in the motion process of the drive component. Please refer to Figure 4 , Figure 4 The schematic diagram of the principle of mobile reverse clearance compensation is shown in the figure. Taking the cutting of a circular hole as an example, when the cutting trajectory reaches point e, the driving speed of the Y axis reaches the maximum, and its driving direction is the positive direction of the Y axis; while the driving speed of the X axis reaches the minimum, and the X axis needs to rotate in the opposite direction at point e. The reverse clearance at this time will affect the precision control of the X axis. When the first drive motor implements reverse clearance compensation, there is a response lag when switching to reverse rotation. Therefore, the compensation curve corresponding to point a to point b is the first curve segment, the compensation curve corresponding to point b to point c is the second curve segment, and the compensation curve corresponding to point c to point d is the third curve segment. After the first drive motor switches to reverse rotation, based on the closed-loop control logic of the first drive motor, the cutting trajectory controlled by it will gradually approach the normal trajectory, so the reverse compensation amount will gradually decrease.

[0055] S14-3, according to the first curve segment, the acousto-optic deflection assembly and the galvanometer assembly are controlled to perform the mobile reverse gap compensation of the driving assembly. In the first curve segment, the reverse compensation amount to be applied is large, and the galvanometer assembly is in the startup state. In order to improve the accuracy of the mobile reverse gap compensation, it is necessary to control the acousto-optic deflection assembly and the galvanometer assembly to jointly perform the compensation of the driving assembly.

[0056] S14-4, according to the second curve segment, the galvanometer component is controlled to perform the reverse clearance compensation of the driving component. When entering the second curve segment, the compensation amount is gradually reduced, and after the galvanometer is started, it will not be affected by the rotational inertia at the initial startup. The galvanometer component has high precision and flexibility in adjusting the laser beam reflection angle, etc. According to the compensation amount specified by the reverse compensation curve at this stage, the galvanometer angle is adjusted in time, which can effectively compensate for the position error caused by the reverse clearance of the driving component.

[0057] S14-5. Control the acousto-optic deflection assembly to perform mobile reverse gap compensation of the driving assembly according to the third curve segment. When the driving assembly is about to finish mobile reverse gap compensation in the third curve segment, using the acousto-optic deflection assembly to perform reverse gap compensation has its unique advantages. It can quickly change the propagation direction of the light beam, etc., and accurately compensate for the position deviation caused by the reverse gap according to the compensation amount determined by the reverse compensation curve at this stage. By analyzing and segmenting the reverse compensation curve in the above manner, the acousto-optic deflection assembly and the galvanometer assembly are used to perform targeted mobile reverse gap compensation at different stages, aiming to improve the position accuracy of the driving assembly during the entire processing task execution process and ensure the processing quality of ultrafast lasers.

[0058] To further improve the processing quality of ultrafast laser, the control method also includes: In the second mode, it is determined whether the laser beam in the processing task has a focal deviation. When there is no focal deviation, the zoom modulation of the laser beam is not performed; when there is a focal deviation, the zoom component arranged between the galvanometer assembly and the field lens is controlled to perform the zoom modulation of the laser beam. It can be determined whether the laser beam has a focal deviation based on the control parameters of the acousto-optic deflection assembly and the galvanometer assembly. For example, a comprehensive optical path model can be established, and the control parameters of the acousto-optic deflection assembly and the galvanometer assembly can be used as input variables. The optical path model is based on the principles of geometric optics and physical optics, and can calculate the actual propagation path and focal position of the laser beam after being modulated by these two components. By comparing the calculated focal position with the preset correct focal position, if the difference between the two exceeds a certain threshold, it can be determined that the laser beam has a focal deviation. Through the zoom modulation of the ultrafast laser by the zoom component, the energy of the ultrafast laser can be highly concentrated in the tiny area that needs to be processed, thereby improving the resolution and accuracy of the processing.

[0059] The technical solution provided in the embodiments of the present invention has at least the following technical effects or advantages: The technical solution constructs an ultrafast laser processing system based on a laser, an acousto-optic deflection assembly, a galvanometer assembly, a field mirror and a controller. When the optical path modulation range of the processing task is within the first maximum range of the acousto-optic deflection assembly, the controller controls the acousto-optic deflection assembly to enter a first mode, and the acousto-optic deflection assembly modulates the processing path of the laser beam based on the acousto-optic effect, so that the processing path modulation of the laser beam meets the corresponding requirements of accuracy and efficiency; when the optical path modulation range is greater than the first maximum range and is within the second maximum range of the galvanometer assembly, the acousto-optic deflection assembly and the galvanometer assembly are controlled to enter a second mode to perform processing path modulation of the laser beam. In the second mode, the acousto-optic deflection assembly and the galvanometer assembly jointly implement the processing path modulation of the laser beam, and the acousto-optic deflection assembly compensates for the response hysteresis of the galvanometer assembly in performing the processing path modulation, so that the processing path modulation of the laser beam can also meet the corresponding requirements of accuracy and efficiency. The heat generated by the ultrafast laser will not be focused on the local area of ​​the processing component, thereby reducing the local ablation defects caused by the ultrafast laser during the processing process.

[0060] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0061] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. An ultrafast laser processing system, characterized in that: The system comprises: Lasers, used to emit laser beams with pulse widths below picoseconds for processing tasks; an acousto-optic deflection assembly, arranged adjacent to the laser; the acousto-optic deflection assembly is used to perform processing path modulation of the laser beam in a first mode, and output the modulated laser beam to the outside through a field lens; a galvanometer assembly, arranged adjacent to the acousto-optic deflection assembly; the galvanometer assembly is used to perform processing path modulation of the laser beam based on the acousto-optic deflection assembly in the second mode, and output the modulated laser beam to the outside through the field mirror; A controller is connected to the laser, the acousto-optic deflection assembly and the galvanometer assembly, and is used to control the acousto-optic deflection assembly to enter the first mode when the optical path modulation range of the processing task is within the first maximum range of the acousto-optic deflection assembly; and to control the acousto-optic deflection assembly and the galvanometer assembly to enter the second mode when the optical path modulation range is greater than the first maximum range and is within the second maximum range of the galvanometer assembly, so as to compensate for the response hysteresis of the galvanometer assembly in performing processing path modulation through the acousto-optic deflection assembly.

2. The ultrafast laser processing system according to claim 1, characterized in that: The system further comprises: A gantry, the crossbeam of which is used to mount the laser, the acousto-optic deflection assembly, the galvanometer assembly and the field mirror; A driving component is installed on the gantry, and a driving port of the driving component is connected to the controller; the driving component is used to drive the X-axis and Y-axis of the gantry to move based on the controller, so that the processing range of the laser beam is larger than the second maximum range; The controller is also used to control the acousto-optic deflection assembly and / or the galvanometer assembly to perform movement backlash compensation of the drive assembly when the drive assembly responds to a processing task greater than the second maximum range.

3. The ultrafast laser processing system according to claim 1, characterized in that: The acousto-optic deflection assembly comprises: an X-direction acousto-optic deflector, configured to perform response hysteresis compensation on the X-direction galvanometer of the galvanometer assembly in the second mode; The Y-direction acousto-optic deflector is used to perform response delay compensation on the Y-direction galvanometer of the galvanometer assembly in the second mode.

4. The ultrafast laser processing system according to claim 1, characterized in that: The system further comprises: A zoom component is arranged between the galvanometer component and the field lens, and a control port of the zoom component is connected to the controller. The zoom component is used to perform zoom modulation of the laser beam based on the controller when the laser beam has a focal length deviation in the second mode.

5. A method for controlling an ultrafast laser processing system, characterized in that: Applicable to the processing system described in any one of claims 1 to 4, the processing system comprises a laser, an acousto-optic deflection assembly, a galvanometer assembly and a field mirror arranged in sequence along the optical path direction; the method comprises: In a processing task, the laser is controlled to emit a laser beam having a pulse width less than picoseconds; When the optical path modulation range of the processing task is within the first maximum range of the acousto-optic deflection assembly, controlling the acousto-optic deflection assembly to perform processing path modulation of the laser beam in a first mode, and outputting the modulated laser beam to the outside through the field lens; When the optical path modulation range is greater than the first maximum range and is within the second maximum range of the galvanometer assembly, the acousto-optic deflection assembly and the galvanometer assembly are controlled to jointly perform processing path modulation of the laser beam in the second mode, and the modulated laser beam is output to the outside through the field lens, so as to compensate for the response lag of the galvanometer assembly in performing processing path modulation through the acousto-optic deflection assembly.

6. The processing system control method according to claim 5, characterized in that: Before controlling the acousto-optic deflection assembly and the galvanometer assembly to jointly perform the processing path modulation of the laser beam in the second mode, the method further includes: Determine whether the processing task has a target working condition, wherein the target working condition is the start-up working condition of the galvanometer assembly, or the curvature change of the task curve of the processing task of the galvanometer assembly is greater than a preset threshold, or the angle between adjacent line segments of the processing task of the galvanometer assembly is within a preset range; If so, an admission instruction for the second mode is output.

7. The processing system control method according to claim 5, characterized in that: The processing system further includes a gantry, and the crossbeam of the gantry is used to install the laser, the acousto-optic deflection assembly, the galvanometer assembly and the field mirror; the method further includes: When the driving component installed on the gantry responds to a processing task greater than the second maximum range, the acousto-optic deflection component and / or the galvanometer component is controlled to perform movement reverse clearance compensation of the driving component; wherein the driving component is used to drive the X-axis and Y-axis movement of the gantry based on a controller so that the processing range of the laser beam is greater than the second maximum range.

8. The processing system control method according to claim 7, characterized in that: The step of controlling the acousto-optic deflection assembly and / or the galvanometer assembly to perform movement backlash compensation of the driving assembly comprises: Determining a reverse compensation curve of the drive component according to the drive parameters corresponding to the drive component when executing the processing task, wherein the reverse compensation curve is a curve showing the reverse compensation amount changing with compensation time; Dividing the reverse compensation curve into a first curve segment, a second curve segment and a third curve segment in sequence along its compensation time; Controlling the acousto-optic deflection assembly and the galvanometer assembly to perform movement backlash compensation of the driving assembly according to the first curve segment; Controlling the galvanometer assembly to perform movement backlash compensation of the driving assembly according to the second curve segment; The acousto-optic deflection assembly is controlled according to the third curve segment to perform movement reverse gap compensation of the driving assembly.

9. The processing system control method according to claim 5, characterized in that: The step of controlling the acousto-optic deflection assembly and the galvanometer assembly to jointly perform processing path modulation of the laser beam in the second mode includes: Establishing compensation relationships between the X-direction acousto-optic deflector and the Y-direction acousto-optic deflector of the acousto-optic deflection assembly and the X-direction galvanometer and the Y-direction galvanometer of the galvanometer assembly respectively; Determine, in the second mode, an actual deflection curve and a theoretical deflection curve corresponding to each galvanometer in the galvanometer assembly when performing the processing task, wherein the actual deflection curve is a curve showing that the actual deflection angle of the galvanometer changes with the deflection time, and the theoretical deflection curve is a curve showing that the theoretical deflection angle of the galvanometer changes with the deflection time; According to the difference between the actual deflection curve of each galvanometer and the theoretical deflection curve, a compensation curve of the corresponding galvanometer is obtained; According to the compensation curve and the compensation relationship, the X-direction AOD and the Y-direction AOD are controlled to perform response delay compensation.

10. The processing system control method according to claim 5, characterized in that: The method further comprises: In the second mode, determining whether a laser beam in the processing task has a focus deviation; If so, the zoom assembly disposed between the galvanometer assembly and the field lens is controlled to perform zoom modulation of the laser beam.

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