Laser processing process two-dimensional monitoring system and method based on track compensation mechanism

Abstract

The invention provides a two-dimensional monitoring system and method for a laser processing process based on a track compensation mechanism, and the system comprises a laser light source, a detection module, a galvanometer, a processing assembly and a control module, and a detection light beam outputted by the detection module enters the processing assembly through the galvanometer, and is used for collecting a light signal returned on a detection light scanning path; a processing light beam output by the laser light source is incident to the processing assembly; the machining assembly coaxially couples the two light beams and then machines a workpiece to be machined. The control module is used for generating a two-dimensional section image for two-dimensional monitoring of the laser processing process according to the optical signal; according to the invention, real-time dynamic monitoring of the section morphology of the material in the laser processing process is realized, the controllability and stability of the processing process are improved, and a visual and efficient online feedback means is provided for laser processing quality regulation and control.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing, and particularly relates to a two-dimensional monitoring system and method for a laser processing process based on a trajectory compensation mechanism. Background Art

[0002] Laser processing has the advantages of high processing accuracy, high efficiency, wide material processing range, non-contact processing, and no tool loss. In the actual operation process of laser processing, affected by the dual characteristics of non-contact processing and Gaussian light transmission characteristics, it is difficult to effectively control the processing depth by means of axis feeding. Moreover, even within a certain range near the focus, the laser beam will still cause damage to the processed material. At the same time, the transmission process of the laser is extremely vulnerable to interference from complex phenomena such as structural evolution and plasma eruption during the processing process, which makes the processing process fluctuate, and thus it is difficult to ensure the processing repeatability and stability, becoming the key factor restricting the improvement of its processing quality.

[0003] At present, the main method to solve the instability of the laser processing process is laser processing process monitoring, that is, by capturing the signals generated when the laser interacts with the processed material, analyzing the signal characteristics to obtain the processing state information, so as to regulate the processing process. However, in the existing monitoring methods, the connection between the signal and the processing process is mostly indirect, and it is impossible to intuitively show the real-time change of the surface morphology of the material during the laser processing process. Moreover, a large number of preliminary experiments need to be carried out in the early stage to obtain the monitoring parameters, making it difficult to achieve efficient and intuitive monitoring of the laser processing process, which restricts the development of laser processing technology. Summary of the Invention

[0004] The purpose of the present invention is to provide a two-dimensional monitoring system and method for a laser processing process based on a trajectory compensation mechanism, which solves the defect that the connection between the signal and the processing process in the existing laser processing process monitoring method is mostly indirect, and it is impossible to intuitively show the real-time change of the material morphology during the laser processing process, resulting in inaccurate monitoring results.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is: In the first aspect, a two-dimensional monitoring method for a laser processing process based on a trajectory compensation mechanism provided by the present invention includes a laser light source, a detection module, a galvanometer scanner, a processing component, and a control module, wherein: The detection light beam output by the detection module is incident on the processing component through the galvanometer scanner to collect the optical signal returned on the detection light scanning path; The processing light beam output by the laser light source is incident on the processing component; The processing component co-axially couples the two beams of light and then processes the workpiece to be processed; The control module is used to generate a two-dimensional cross-sectional image for two-dimensional monitoring of the laser processing process according to the optical signal.

[0006] Preferably, the processing assembly includes a processing assembly, a first dichroic mirror, a first focusing lens, and a processing platform, where: The beams output by the laser light source and the detection module are both incident on the first dichroic mirror. The beam output by the first dichroic mirror is incident on the processing assembly, and the beam output by the processing assembly passes through the first focusing lens and is incident on the processing platform.

[0007] Preferably, the detection module includes an SLD light source, a beam coupler, a first beam collimator, a second dichroic mirror, a second beam collimator, a third beam collimator, a second focusing lens, a third focusing lens, a mirror, a transmission grating, and a line array camera, where: The beam output by the SLD light source is incident on the beam coupler. One of the two detection beams output by the beam coupler passes through the first beam collimator and is incident on the second dichroic mirror; The detection beam output by the second dichroic mirror is incident on the galvanometer; The other detection beam output by the beam coupler passes through the second beam collimator and the second focusing lens in sequence and is incident on the mirror. The detection optical signal output by the mirror is incident on the beam coupler; The two detection optical signals received by the beam coupler pass through the third beam collimator, the transmission grating, and the third focusing lens in sequence and are incident on the line array camera; The line array camera is used to collect the optical signal returned on the detection beam scanning path; The industrial camera is used to collect the image information of the surface of the workpiece to be processed.

[0008] In a second aspect, the present invention provides a two-dimensional monitoring method for a laser processing process based on a trajectory compensation mechanism, including the following steps: Step 1, obtain the detection beam scanning path according to the preset laser processing trajectory, and set the scanning speed and the number of detection scans of the detection beam; Step 2, generate the compensation movement trajectory of the galvanometer according to the preset laser processing trajectory and laser processing speed, as well as the detection beam scanning path, detection beam scanning speed, and the number of detection scans; Step 3, use the pre-constructed galvanometer movement trajectory - deflection model to convert the compensation movement trajectory of the galvanometer into the movement parameters of the galvanometer deflection angle; Step 4, initialize the laser processing parameters, detection module parameters, and galvanometer movement parameters, synchronously control the laser light source, processing assembly, galvanometer, and detection module, perform laser processing on the workpiece to be processed, and simultaneously collect the optical signal returned on the detection beam scanning path; Step 5: Obtain a two-dimensional cross-sectional image based on the obtained optical signal, and use the two-dimensional cross-sectional image to perform two-dimensional monitoring on the laser processing process.

[0009] Preferably, obtain the detection light scanning path according to the preset laser processing trajectory. The specific method is as follows: The detection light scanning path is a straight line passing through the laser processing trajectory.

[0010] Preferably, generate the compensation motion trajectory of the galvanometer. The specific method is as follows: According to the preset laser processing trajectory and laser processing speed, as well as the detection light scanning path, detection light scanning speed, and detection scanning times, calculate the offset between the processing light focus coordinates and the detection light focus coordinates corresponding to different moments; Use the obtained offset values on the X-axis and Y-axis as the coordinate values of the compensation motion trajectory of the galvanometer; Generate the compensation motion trajectory of the galvanometer by splicing the obtained coordinate values of multiple compensation motion trajectories.

[0011] Preferably, construct a galvanometer motion trajectory - deflection model. The specific method is as follows: Measure the distance between the X-axis galvanometer mirror and the Y-axis galvanometer mirror in the optical path, the optical path between the Y-axis galvanometer mirror and the first dichroic mirror, and the distance between the first dichroic mirror and the processing platform, and deduce the relationship between any coordinate on the galvanometer motion trajectory and the galvanometer deflection angle; Perform reverse solution on the relationship between any coordinate on the galvanometer motion trajectory and the galvanometer deflection angle to obtain the galvanometer motion trajectory - deflection model.

[0012] Preferably, the expression of the galvanometer motion trajectory - deflection model is:

[0013]

[0014] where, θx and θy are the deflection angles of the galvanometer; e is the distance between the X-axis galvanometer mirror and the Y-axis galvanometer mirror; d is the optical path between the Y-axis galvanometer mirror and the first dichroic mirror; L is the distance between the first dichroic mirror and the processing platform; (x, y) is any coordinate on the galvanometer motion trajectory.

[0015] Preferably, obtain the two-dimensional cross-sectional image according to the obtained optical signal. The specific method is as follows: Interfere the obtained optical signal with the reflected reference light received in the detection module to obtain an interference signal; Perform preprocessing of removing direct current and wavenumber linearization on the obtained interference signal in sequence to obtain the preprocessed interference signal; Perform a Fourier transform on the obtained preprocessed interference signal to obtain the point depth information at different times; Generate a three-dimensional point cloud dataset from the point depth information at different times; Generate a two-dimensional cross-sectional image using the obtained three-dimensional point cloud dataset.

[0016] Preferably, between step 3 and step 4, it also includes adjusting the center position between the probe light spot and the processing light spot to make the center position deviation between the probe light spot and the processing light spot less than a preset value.

[0017] Compared with the prior art, the beneficial effects of the present invention are: A two-dimensional monitoring system and method for a laser processing process based on a trajectory compensation mechanism provided by the present invention. First, according to the laser processing path, plan the probe light scanning path, and then calculate the deflection angle of the galvanometer in combination with the pre-constructed galvanometer motion trajectory-deflection model. Synchronously control the processing component, the galvanometer, and the detection module to process the workpiece to be processed, and at the same time collect the optical signal on the scanning path. Finally, generate a two-dimensional cross-sectional topography image from the optical signal to realize the two-dimensional topography monitoring of the laser processing process; the present invention realizes the real-time dynamic monitoring of the material cross-sectional topography during the laser processing process, improves the controllability and stability of the processing process, and provides an intuitive and efficient online feedback means for the quality control of laser processing.

[0018] The present invention provides a two-dimensional monitoring system for a laser processing process based on a trajectory compensation mechanism. Through a dichroic mirror and a beam transmission system, coaxial coupling of the interference measurement and the processing optical path is realized; through the compensation of the galvanometer for the motion trajectory of the processing component, two-dimensional cross-sectional interference measurement of the target material is realized, and the evolution process of the target cross-sectional topography during the processing process is monitored in real time; the present invention realizes the real-time dynamic monitoring of the material cross-sectional topography during the laser processing process, improves the controllability and stability of the processing process, and provides an intuitive and efficient online feedback means for the quality control of laser processing. Description of the Drawings

[0019] Figure 1 is the general flowchart of the method of the embodiment of the present invention; Figure 2 is the schematic diagram of the method of the galvanometer trajectory compensation algorithm of the embodiment of the present invention Figure 3 is the schematic diagram of the galvanometer motion trajectory-deflection model of the embodiment of the present invention; Figure 4 is the flowchart of the method of the synchronous control system of the embodiment of the present invention; Figure 5 is the flowchart of the method for obtaining the real-time two-dimensional cross-sectional topography of laser processing of the embodiment of the present invention; Figure 6 is the general schematic diagram of the system of the embodiment of the present invention; Figure 7 It is a schematic diagram of the detection module of the present invention; Among them, 1. Laser; 2. First dichroic mirror; 3. Processing component; 4. Detection module; 5. Galvanometer; 6. Focusing lens; 7. Processing platform; 8. Control module; 9. Computer; 10. Industrial camera; 11. SLD light source; 12. Fiber optic coupler; 13. First beam collimator; 14. Transmission grating; 15. Linear array camera; 16. Reflecting mirror; 17. Second beam collimator; 18. Third beam collimator; 19. Second focusing lens; 20. Third focusing lens; 21. Second dichroic mirror. Specific implementation manners

[0020] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system architectures and technologies are presented in order to provide a thorough understanding of the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0021] It should be understood that when used in the specification and appended claims of the present application, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0022] It should also be understood that the term "and / or" used in the specification and appended claims of the present application refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0023] As used in the specification and appended claims of the present application, the term "if" can be interpreted as "when" or "once" or "in response to determining" or "in response to detecting" depending on the context. Similarly, the phrase "if determined" or "if detecting [the described condition or event]" can be interpreted as meaning "once determined" or "in response to determining" or "once detecting [the described condition or event]" or "in response to detecting [the described condition or event]" depending on the context.

[0024] In addition, in the description of the specification and appended claims of the present application, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0025] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that specific features, structures or characteristics described in connection with that embodiment are included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments" etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0026] Embodiment 1 The purpose of this embodiment is to combine an optical coherence interferometry system with a galvanometer compensation scanning technique and a synchronous control algorithm to collect point depth information during the laser processing process in real time and construct a dynamic two-dimensional cross-sectional topography image, solve the defects of traditional monitoring methods that rely on indirect signals, require pre-experiment parameters and cannot intuitively reflect the change of material topography, realize efficient online two-dimensional visualization monitoring of the processing process, improve the stability and controllability of laser processing, and provide an intuitive and efficient online feedback means for laser processing quality control.

[0027] As Figures 1 to 6 shown, a two-dimensional monitoring method for the laser processing process based on a trajectory compensation mechanism provided in this embodiment includes the following steps: Step 1, according to the preset laser processing trajectory of the workpiece to be processed, select a straight line passing through the laser processing trajectory as the detection light scanning path; according to the hardware parameters of the detection module 4, as well as the preset detection light scanning distance L and scanning frequency f, calculate the detection light scanning speed V = L * f; As Figure 2 , according to the preset laser processing trajectory and laser processing speed, as well as the detection light scanning path, detection light scanning speed and detection scanning times, calculate the offsets Δx = x1 - x2, Δy = y1 - y2 of the processing light focus coordinates (x1, y1) and the detection light focus coordinates (x2, y2) corresponding to different times T; Take the offsets of the X-axis and Y-axis as the coordinate values of the compensation movement trajectory of the galvanometer. Accordingly, the compensation movement coordinates of the galvanometer corresponding to different times T can be obtained, and the compensation movement trajectory of the galvanometer is generated by splicing; Step 2, construct the mapping relationship between the galvanometer deflection angle and the processing platform coordinates based on the geometric optical model; As Figure 3, measure the distance \(e\) between the X-axis galvanometer mirror and the Y-axis galvanometer mirror, the optical path \(d\) between the Y-axis galvanometer mirror and the first dichroic mirror, and the distance \(L\) between the first dichroic mirror and the processing platform in the measurement optical path. According to geometric relationships, the relationship between any coordinate \((x, y)\) on the galvanometer movement trajectory and the deflection angles \(\theta_x\) and \(\theta_y\) of the galvanometer can be derived as follows:

[0028]

[0029] Solving the angles \(\theta_x\) and \(\theta_y\) inversely can obtain the galvanometer movement trajectory - deflection model, as shown below:

[0030]

[0031] According to the galvanometer movement trajectory - deflection model, convert the galvanometer compensation movement trajectory obtained in step 1 into the movement parameters of the galvanometer deflection angle. Among them, the movement parameters include the deflection angle and angular velocity, and save them as the movement parameters of the galvanometer compensation movement to the control module 8.

[0032] Step 3, preset a marked point on the surface of the processed material as the positioning reference. The industrial camera 10 performs image acquisition on the corresponding processing area of the processed material through the coaxial optical path formed by the detection light and the industrial camera being coaxially coupled, and combines the image processing algorithm to complete the visual positioning of the processing area and the coincidence of the processing light spot and the detection light spot; in order to better observe the processing situation and the spot coincidence situation of the processing area through the PC, the coincidence of the processing light spot and the detection light spot is to ensure the accuracy of the calculation of the compensation trajectory.

[0033] For the described image processing algorithm, the original image extracts the contour information of the mark through the Gaussian filtering and edge detection algorithms, and calculates the center coordinates of the marked point , turn on the processing light and the detection light respectively, obtain the position deviation between the processing light spot and the detection light spot after collecting the two spot images, and adjust the position and angle of the optical elements in the optical path to achieve the coincidence of the two spots; Step 4, initialize the laser processing parameters, the detection module 4, and the galvanometer movement parameters. Through the control module 8, synchronously control the laser, the processing component, the galvanometer, and the detection module to complete the processing of the laser workpiece to be processed. At the same time, collect the optical signals returned on the detection light scanning path, perform signal processing on the optical signals, construct a two-dimensional cross-sectional image, and use the two-dimensional cross-sectional image to perform two-dimensional monitoring on the laser processing process.

[0034] The described laser processing parameters include laser power, laser repetition frequency, processing trajectory, and processing speed.

[0035] The parameters of the detection module include the trigger mode, line scanning speed, and exposure time of the line array camera.

[0036] The galvanometer motion parameters include the galvanometer deflection motion parameters obtained in step 2.

[0037] As Figure 4 , after initializing the parameters, the synchronous control algorithm is started by the control module, and at the same time, the laser is turned on, the processing component moves, the galvanometer scans, and the detection module collects data, ensuring that the detection light can move along the preset scanning path under the preset processing trajectory, and the returned optical signal is collected by the detection module; when the workpiece to be processed this time is completed, the processing process is stopped.

[0038] The control module includes a motion control card, a signal generator, and an image acquisition card; The optical signal is processed to construct a two-dimensional cross-sectional image. As Figure 5 shown, the specific method flow is as follows: After the returned optical signal enters the beam coupler in the detection module, it interferes with the reference beam reflected back in the detection module and is collected by the line array camera; The interference signal is processed. The interference signal is preprocessed by removing the direct current and wave number linearization, and then the preprocessed interference signal is demodulated by Fourier transform to obtain the point depth information at different times T; Combined with the detection light scanning path in step 1, the depth information corresponding to the scanning trajectory is obtained after each detection light completes scanning, and a three-dimensional point cloud dataset is generated accordingly. The point cloud is projected onto the X-Z plane (along the scanning path direction), and an interpolation algorithm is used to generate a two-dimensional cross-sectional image.

[0039] In this application, in laser processing, the optical coherence imaging technology actively emits detection light into the processing area (such as the molten pool, keyhole, or hole), and uses the reflected detection light signal to generate a two-dimensional cross-sectional image, which can directly present the geometric structure changes in the processing area. For example, during laser welding, the two-dimensional cross-sectional image can display the depth, roughness of the keyhole, and the fluctuation state of the molten pool in real time. These morphological parameters are directly related to the processing quality. For example, for laser drilling, the two-dimensional cross-sectional image can clearly show the depth of the hole, the uniformity of the hole diameter, and the penetration state of the hole bottom.

[0040] At the present stage, the online monitoring methods for laser processing mainly focus on passively capturing various signals generated during the interaction between laser and materials, and classifying and analyzing them using different signal processing methods. This type of monitoring method cannot intuitively display the real-time changes in the material morphology during the laser processing process, and it is difficult to directly obtain coordinate information such as depth and aperture. At the same time, in the actual application process of laser processing monitoring, different application scenarios, processing parameters, and experimental conditions will all affect the actual effects of these monitoring means. Therefore, a large number of preliminary experiments are often required before starting real-time processing monitoring. Whenever it is necessary to change the usage scenario or processing material, repeated preliminary pre-experiments need to be carried out. Optical coherence imaging technology is different from traditional monitoring means. Since it does not need to passively receive the signals generated by processing, but actively emits detection light to the sample, and through galvanometer scanning, a two-dimensional image during the processing process can be clearly and intuitively obtained to characterize the microscopic structure changes of the sample. At the same time, this method does not require a large number of preliminary pre-experiments, and different experimental conditions and processing parameters will not affect the online monitoring images, reducing the time for preliminary work. In addition, this method can also be coaxially coupled with the processing system and has strong adaptability to various laser processing scenarios.

[0041] Embodiment 2 As Figure 6 shown, a two-dimensional monitoring system for laser processing based on a trajectory compensation mechanism provided in this embodiment includes a laser 1, a first dichroic mirror 2, a processing component 3, a detection module 4, a galvanometer 5, a focusing lens 6, a processing platform 7, a control module 8, and a computer 9, where: The laser beam output by the laser 1 is reflected by the first dichroic mirror 2 and then enters the processing component 3, and is output to the focusing lens 6 by the processing component 3 for focusing, and then acts on the target material on the processing platform 7.

[0042] The detection light emitted by the detection module 4 is deflected by the galvanometer 5 and then transmitted through the first dichroic mirror 2 to be coaxially coupled with the processing laser beam, enters the processing component 3, and is then output to the focusing lens 6 and focused on the target material.

[0043] The processing component 3 includes a rotary cutting head, a galvanometer, and a multi-axis moving table, which is a laser processing device that can preset the processing trajectory.

[0044] As Figure 7 , the detection module 4 includes an industrial camera 10, an SLD light source 11, an optical fiber coupler 12, a first beam collimator 13, a transmission grating 14, a line array camera 15, a reflector 16, a second beam collimator 17, a third beam collimator 18, a second focusing lens 19, a third focusing lens 20, and a second dichroic mirror 21, where: The laser beam emitted by the SLD light source 18 is transmitted to the beam coupler 12 through an optical fiber. The beam coupler 12 divides it into two beams of light. One beam of detection light passes through the first beam collimator 13 and is transmitted out of the detection module through the second dichroic mirror 21. The other beam of detection light passes through the second beam collimator 17, is focused by the third focusing lens 19 onto the mirror 11, and then reflected back to the beam coupler 12, where it is coupled with the optical signal in the processing process returning to the beam coupler 12. Then, it enters the transmission grating 14 through the third beam collimator 18, is focused by the third focusing lens 20, and is collected by the linear array camera 15.

[0045] The industrial camera 10 is used to collect the image information of the surface of the workpiece to be processed.

[0046] The control module 8 includes systems such as a motion control card and a signal generator that can output synchronous control signals.

[0047] Although this specification uses terms such as laser, dichroic mirror, detection module, galvanometer, focusing lens, target material, industrial camera, collimator, beam coupler, transmission grating, trajectory compensation algorithm, motion trajectory - deflection model, etc. more frequently, it does not exclude the possibility of using other terms. Using these terms is only to more conveniently describe the essence of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.

[0048] Embodiment 3 Turning head processes the film cooling holes of the blade Taking the laser processing of the film cooling holes of the blade as an example, with the nickel - based superalloy blade as the target material and the laser beam swiveling module turning head as the processing component, it mainly includes the following steps: Step 1: Determine the processing parameters of the turning head according to the diameter, depth, and inclination angle of the film cooling hole to be processed, and select concentric circle turning processing for the processing trajectory; Step 2: Select a straight line passing through the center of the concentric circles in the processing area on the processing platform as the detection light scanning path. According to the processing trajectory, processing speed, detection light scanning path, detection light scanning speed, and detection scanning times, calculate the offset amounts Δx = x1 - x2 and Δy = y1 - y2 between the processing light focus coordinates (x1, y1) and the detection light focus coordinates (x2, y2) at different times T. Take the offset amounts of the X - axis and Y - axis as the coordinate values of the compensation motion trajectory of the galvanometer, and calculate the change of the deflection angle during the processing according to the galvanometer motion trajectory - deflection model; Step 3: Turn on the detection module 4 and the laser demonstration light, use the industrial camera 10 to collect the image information of the surface of the workpiece to be processed, extract the center positions of the processing light and detection light spots through the edge detection algorithm, and adjust the optical mirror frame so that the center deviation between the processing light and the detection light is < 1μm; Step 4: Initialize the laser processing parameters including laser power, rotary cutting head processing speed, and galvanometer compensation trajectory. Generate a synchronization signal using the motion control card to control the laser beam output, rotation of the rotary cutting head, deflection of the galvanometer, and exposure of the linear array camera. The linear array camera collects the returned interference images, and the industrial camera 10 monitors the orifice morphology in real time. Step 5: After removing the direct current, wave number linearization, and Fourier transform of the interference signal, analyze the hole depth z. Combine the detection light scanning path information after each scan, and generate multiple groups of three-dimensional point cloud data after mutual matching. After projecting onto the scanning section, obtain the real-time two-dimensional cross-sectional morphology map of the air film cooling hole.

[0049] Example 4 Selective laser melting processing of rotor parts Taking the selective laser melting processing of rotor parts as an example, using a processing galvanometer as the processing component and the target material being 316L stainless steel, mainly including the following steps: Step 1: Plan the rotor contour on the stainless steel powder bed, and the scanning path of the processing galvanometer is reciprocating filling. Step 2: Take the position offset by 0.1 mm along the scanning trajectory of the processing galvanometer as the detection light scanning path, covering the molten pool edge. According to the processing trajectory, processing speed, detection light scanning path, detection light scanning speed, and the set number of detection scans according to the imaging speed of the detection module, calculate the offset amounts Δx = x1 - x2 and Δy = y1 - y2 of the processing light focus coordinates (x1, y1) and the detection light focus coordinates (x2, y2) at different times T. Take the offset amounts of the X-axis and Y-axis as the coordinate values of the galvanometer compensation motion trajectory, and calculate the change of the deflection angle during the processing according to the galvanometer motion trajectory - deflection model. Step 3: Turn on the detection module and the laser demonstration light, collect images using the industrial camera, extract the center positions of the processing light and detection light spots through the edge detection algorithm, and adjust the optical mirror frame to make the center deviation between the processing light and the detection light < 1 μm. Step 4: Initialize the laser processing parameters including laser power, processing speed of the processing galvanometer, and galvanometer compensation trajectory. Generate a synchronization signal using the motion control card to control the laser beam output, rotation of the rotary cutting head, deflection of the galvanometer, and exposure of the linear array camera. The linear array camera collects the returned interference images, and the industrial camera monitors the dynamic state of the molten pool in real time. Step 5: After removing the direct current, wave number linearization, and Fourier transform of the interference signal, analyze the molten pool depth z. Combine the detection light scanning path information after each scan, and generate multiple groups of three-dimensional point cloud data after mutual matching. After projecting onto the scanning section, obtain the real-time two-dimensional cross-sectional morphology map of the molten pool.

[0050] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included within the protection scope of the present application.

Claims

1. A two-dimensional monitoring system for laser processing based on trajectory compensation mechanism, characterized in that: It includes a laser light source, a detection module, a galvanometer, a processing component and a control module, wherein: The detection light beam output by the detection module is incident on the processing component through the galvanometer to collect the light signal returned on the detection light scanning path; The processing light beam output by the laser light source is incident on the processing component; The processing component processes the workpiece to be processed after coaxially coupling the two light beams; The control module is used to generate a two-dimensional cross-sectional image for two-dimensional monitoring of the laser processing process according to the optical signal.

2. A two-dimensional monitoring system for laser processing based on trajectory compensation mechanism according to claim 1, characterized in that: The processing assembly comprises a processing assembly, a first dichroic mirror, a first focusing lens and a processing platform, wherein: The light beam output by the laser light source and the light beam output by the detection module are both incident on the first dichroic mirror, the light beam output by the first dichroic mirror is incident on the processing component, and the light beam output by the processing component is incident on the processing platform through the first focusing lens.

3. The two-dimensional monitoring system for laser processing based on trajectory compensation mechanism according to claim 1, characterized in that: The detection module includes an SLD light source, a beam coupler, a first beam collimator, a second dichroic mirror, a second beam collimator, a third beam collimator, a second focusing lens, a third focusing lens, a reflector, a transmission grating and a linear array camera, wherein: The light beam output by the SLD light source is incident on the beam coupler, and one of the two beams of detection light output by the beam coupler is incident on the second dichroic mirror through the first beam collimator; The detection light output by the second dichroic mirror is incident on the galvanometer mirror; The other one of the two detection lights output by the beam coupler passes through the second beam collimator and the second focusing lens in sequence and is incident on the reflector, and the detection light signal output by the reflector is incident on the beam coupler; The two detection light signals received by the beam coupler are sequentially incident on the linear array camera through the third beam collimator, the transmission grating and the third focusing lens; The linear array camera is used to collect the light signal returned on the detection light scanning path; The industrial camera is used to collect image information of the surface of the workpiece to be processed.

4. A two-dimensional monitoring method for laser machining process based on trajectory compensation mechanism, characterized in that: The following steps are involved: Step 1, obtaining the detection light scanning path according to the preset laser processing trajectory, and setting the scanning speed and detection scanning times of the detection light; Step 2, generating a compensation motion trajectory of the galvanometer according to a preset laser processing trajectory and laser processing speed, as well as a detection light scanning path, a detection light scanning speed, and a detection scanning number; Step 3, using a pre-constructed galvanometer motion trajectory-deflection model to convert the galvanometer compensation motion trajectory into motion parameters of the galvanometer deflection angle; Step 4, initializing laser processing parameters, detection module parameters and motion parameters of the galvanometer, synchronously controlling the laser light source, processing components, galvanometer and detection module, performing laser processing on the workpiece to be processed, and collecting the light signal returned on the detection light scanning path; Step 5, obtaining a two-dimensional cross-sectional image according to the obtained optical signal, and using the two-dimensional cross-sectional image to perform two-dimensional monitoring of the laser processing process.

5. A two-dimensional monitoring method for laser machining process based on trajectory compensation mechanism according to claim 4, characterized in that: The detection light scanning path is obtained according to the preset laser processing trajectory. The specific method is: The detection light scanning path is a straight line running through the laser processing track.

6. The two-dimensional monitoring method of laser processing process based on trajectory compensation mechanism according to claim 4 is characterized in that: Generate the compensation motion trajectory of the galvanometer. The specific method is: According to the preset laser processing trajectory and laser processing speed, as well as the detection light scanning path, the detection light scanning speed and the detection scanning times, the offset between the processing light focus coordinates and the detection light focus coordinates corresponding to different times is calculated; The obtained X-axis and Y-axis offsets are used as coordinate values ​​of the compensation motion trajectory of the galvanometer; The coordinate values ​​of the obtained multiple compensation motion trajectories are spliced ​​to generate the compensation motion trajectory of the galvanometer.

7. The two-dimensional monitoring method of laser processing process based on trajectory compensation mechanism according to claim 4 is characterized in that: Construct the galvanometer motion trajectory-deflection model. The specific method is: The distance between the X-axis galvanometer lens and the Y-axis galvanometer lens in the optical path, the optical path between the Y-axis galvanometer lens and the first dichroic mirror, and the distance between the first dichroic mirror and the processing platform are measured to derive the relationship between any coordinate on the galvanometer motion trajectory and the galvanometer deflection angle; The relationship between any coordinate on the galvanometer motion trajectory and the galvanometer deflection angle is reversely solved to obtain the galvanometer motion trajectory-deflection model.

8. A two-dimensional monitoring method for laser machining process based on trajectory compensation mechanism according to claim 4 or 7, characterized in that: The expression of the galvanometer motion trajectory-deflection model is: Among them, θx and θy are the deflection angles of the galvanometer; e is the distance between the X-axis galvanometer lens and the Y-axis galvanometer lens; d is the optical path between the Y-axis galvanometer lens and the first dichroic mirror; L is the distance between the first dichroic mirror and the processing platform; (x, y) is any coordinate on the galvanometer motion trajectory.

9. The two-dimensional monitoring method of laser processing process based on trajectory compensation mechanism according to claim 4, characterized in that: The two-dimensional cross-sectional image is obtained according to the obtained optical signal. The specific method is: interfering the obtained optical signal with the reflected reference light received in the detection module to obtain an interference signal; The obtained interference signal is sequentially preprocessed by removing direct current and performing wave number linearization to obtain a preprocessed interference signal; The obtained pre-processed interference signal is subjected to Fourier transform to obtain the point depth information at different times; Generate a 3D point cloud data set from point depth information at different times; The obtained 3D point cloud dataset is used to generate 2D cross-sectional images.

10. The two-dimensional monitoring method of laser processing process based on trajectory compensation mechanism according to claim 4, characterized in that: Between step 3 and step 4, the method further includes adjusting the center position between the detection light and the processing light spot so as to make the center position deviation between the detection light and the processing light spot smaller than a preset value.

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