Galvanometer scanning laser precision etching method and device based on machine vision measurement feedback
By using machine vision measurement feedback, the position of the laser spot is detected in real time and interpolation calculation is performed, which solves the problem of unstable control of laser etching depth by galvanometer scanning and realizes stable and precise control of laser etching depth.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-03-31
AI Technical Summary
Existing galvanometer scanning laser precision etching technology has difficulty maintaining stable control over processing depth. It is greatly affected by the environment, laser parameters, and material surface condition, especially when forming deep structures through multiple scans, the effect is unstable.
The method of machine vision measurement feedback is adopted. The position of the laser spot is measured in real time by an industrial microscope camera. Combined with interpolation calculation, the laser etching depth is detected and controlled in real time. Closed-loop control is performed using a coaxial indicator light and control software.
It enables real-time detection and control of laser etching depth under complex process conditions, reducing measurement errors and ensuring the stability and accuracy of etching depth.
Smart Images
Figure CN121755901A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of laser etching technology, and more specifically, to a galvanometer scanning laser precision etching method and apparatus with machine vision measurement feedback. Background Technology
[0002] Galvanometer scanning laser precision etching technology is a processing technology that uses a high-speed galvanometer to scan a high-energy laser beam to instantly vaporize or peel off materials to form precise microstructures. It has advantages such as non-contact operation, fast scanning speed, multi-parameter control, and digital control, and has been widely used in the field of materials processing.
[0003] In existing technologies, the effectiveness of laser etching in galvanometer scanning laser precision etching is easily affected by factors such as the processing environment, laser parameters, galvanometer performance, and the cleanliness of the material surface. In particular, when laser etching is used to process microstructures with a certain depth, multiple scans at the same location are required to remove the material and achieve a certain depth. As the etching depth increases, the laser defocusing amount, laser absorption rate, and material surface condition may change, making it difficult to maintain a stable effect of laser etching. This makes controlling the depth of laser precision etching a challenging technical problem. Summary of the Invention
[0004] The purpose of this invention is to provide a galvanometer scanning laser precision etching method and apparatus with machine vision measurement feedback, solving the technical problems in related technologies. To achieve the above objective, this invention provides the following technical solution: A galvanometer scanning laser precision etching method with machine vision measurement feedback, comprising the following steps: S1, aligning an industrial microscope camera with the observation position of the galvanometer scanning laser etching processing area, turning on the coaxial indicator light of the laser, and establishing a mapping table between the center coordinates (x, y) of the laser spot in the image acquired by the microscope camera and the surface height h through a height calibration experiment, and storing it in a computer memory; S2, before starting the laser etching process, setting the processing depth d and other process parameters of the graphic to be processed in the control software on the computer; S3, turning on the coaxial indicator light of the laser in the control software, and the control software detecting the coordinates (x, y) of the laser spot on the surface of the part through the microscope camera. S4. The control software controls the galvanometer to scan the laser according to the set processing graphics and process parameters to perform one laser etching process; S5. The control software turns on the coaxial indicator light of the laser, and the control software detects the laser spot coordinates (xi,yi) on the surface of the part through a microscope camera, calculates the corresponding height hi, and obtains the etching depth value Δh = hi - h0; S6. The control software judges whether the etching depth value Δh has reached the set processing depth d. If it has not reached the processing depth d, it returns to S4 to continue processing. If it has reached the processing depth d, the processing is completed.
[0005] Preferably, in step S1, the height calibration experiment is as follows: standard gauge blocks of different heights h that have been certified by metrology are placed in the processing area. The control software collects the light spots on the surface of the standard gauge blocks through a microscope camera and obtains the pixel coordinates (x, y) of the center of the light spots through a visual recognition algorithm, thereby establishing a one-to-one correspondence mapping table between the center coordinates (x, y) of the light spots and the surface height h, and storing it in the computer memory.
[0006] Preferably, in step S1, after the control software acquires the light spot image through the industrial microscope camera, the control software executes an image processing algorithm to obtain the pixel coordinates (xi,yi) of the light spot center.
[0007] Preferably, in step S3, the interpolation calculation can employ various interpolation calculation methods such as conventional linear interpolation algorithms, quadratic interpolation algorithms, and cubic interpolation algorithms.
[0008] Preferably, in step S4, the scanning path of the laser etching pattern can employ various strategies such as conventional straight-line scanning, loop filling, and partitioned spiral filling.
[0009] A galvanometer scanning laser precision etching apparatus with machine vision measurement feedback is applied to the aforementioned machine vision measurement feedback galvanometer scanning laser precision etching method. In this apparatus, the laser can be a fiber laser or a gas laser. The laser not only emits high-energy processing laser light but also integrates a coaxial indicating laser. The control software can freely select and control the laser beam emission according to processing and measurement needs. The laser and galvanometer are connected via a fixed spatial optical path or fiber optical path. The microscope camera can be fixedly connected to the galvanometer via a mounting bracket or placed above the area to be etched via an independent bracket.
[0010] Preferably, the control computer is connected to the laser, galvanometer, and microscope camera via signal lines. The control computer is equipped with self-developed control software that can control the laser's switching and power parameters, as well as the galvanometer's scanning motion. The microscope camera is a fixed-focus or variable-focus industrial CCD or CMOS microscope camera with millions of pixels or higher. By selecting different magnification objectives and eyepieces, the microscope camera's pixel resolution can reach micrometer or sub-micrometer precision.
[0011] Preferably, the control software has the function of controlling the microscope camera to acquire images, and can identify the center position of the light spot in the image through machine vision algorithms.
[0012] Preferably, the center of the laser spot acquired and identified by the control software through the microscope camera can be an indicator laser spot or a processing laser spot.
[0013] Preferably, the galvanometer can be an industrial 2D galvanometer or a 3D galvanometer.
[0014] Compared with the prior art, the present invention has the following beneficial effects:
[0015] 1. In this invention, by using an industrial microscope camera to measure the position of the laser spot in situ, the height information of the etching area on the workpiece surface is calculated in real time and fed back to the computer control system, thereby realizing closed-loop control of galvanometer scanning laser precision etching with measurement feedback, which can ensure real-time detection and processing control of laser etching depth under various complex process conditions.
[0016] 2. In this invention, an industrial microscope camera is installed next to the galvanometer to measure the laser spot in situ at the processing position on the surface of the part. The measurement process does not require moving or re-clamping the part, which has the advantages of convenient measurement and fewer factors affecting measurement error.
[0017] 3. In this invention, the installation of the measuring device does not affect the optical path of the galvanometer processing system, which is easy to implement and can be widely applied to existing 2D or 3D laser processing systems. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.
[0019] Figure 1 This is a schematic diagram of the device of the present invention;
[0020] Figure 2 This is a schematic diagram of the machine vision measurement principle of the present invention;
[0021] Figure 3 This is a flowchart of the laser etching process of the present invention.
[0022] 1. Control computer; 2. Laser; 3. Galvanometer; 4. Microscope; 5. Components. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.
[0024] Please refer to Figures 1 to 3This invention provides a machine vision measurement feedback method for galvanometer scanning laser precision etching, comprising the following steps: S1, aligning an industrial microscope camera with the observation position of the galvanometer scanning laser etching processing area, turning on the coaxial indicator light of the laser, and establishing a mapping table between the center coordinates (x, y) of the laser spot in the image acquired by the microscope camera and the surface height h through a height calibration experiment, and storing it in the computer memory; S2, before starting the laser etching process, setting the processing depth d and other process parameters of the pattern to be processed in the control software on the computer; S3, turning on the coaxial indicator light of the laser in the control software, and the control software detecting the laser spot coordinates (x0, y0) on the surface of the part through the microscope camera, and then... S4. The control software calls the pre-calibrated height mapping table in the computer memory and calculates the initial height h0 of the part surface through interpolation; S5. The control software controls the galvanometer to scan the laser according to the set processing graphics and process parameters to perform one laser etching process; S6. The control software turns on the coaxial indicator light of the laser and detects the laser spot coordinates (xi,yi) on the part surface through a microscope camera. The control software calculates the corresponding height hi through interpolation and obtains the etching depth value Δh = hi - h0; S7. The control software determines whether the etching depth value Δh has reached the set processing depth d. If it has not reached the processing depth d, it returns to S4 to continue processing. If it has reached the processing depth d, the processing is completed.
[0025] It should be noted that in step S1, the height calibration experiment is as follows: Standard gauge blocks of different heights h, certified by metrology, are placed in the processing area. The control software uses a microscope camera to collect light spots on the surface of the standard gauge blocks and obtains the pixel coordinates (x, y) of the light spot center using a visual recognition algorithm. This establishes a one-to-one mapping table between the light spot center coordinates (x, y) and the surface height h, which is then stored in the computer memory. Figure 2 As shown in the table on the right. During the laser etching process, the control software uses a microscope camera to detect the coordinates (x, y) of the center of the laser spot on the part surface in real time. Then, it calls a pre-calibrated height mapping table in the computer memory and calculates the initial height h of the part surface through interpolation.
[0026] It should be noted that in steps S1, S3, and S5, after the control software acquires the light spot image through the industrial microscope camera, the control software executes an image processing algorithm to obtain the pixel coordinates (x, y) of the light spot center. The specific processing flow is as follows: First, the image is preprocessed, including grayscale conversion, binarization, edge detection, contour extraction, and other preprocessing operations. Then, the geometric center of the light spot is calculated using methods such as the centroid method, circle fitting algorithm, and central moment. The pixel coordinate calculation accuracy is ≤ ±0.5 pixels.
[0027] In this embodiment, the interpolation calculation in steps S3 and S5 can employ linear interpolation algorithms, quadratic interpolation algorithms, or improved bicubic interpolation algorithms. Taking the improved bicubic interpolation algorithm as an example, specifically: select the 8 nearest calibration sampling points in the mapping table to construct a local coordinate-height fitting model; optimize the interpolation calculation by introducing weight coefficients (the weights are inversely proportional to the Euclidean distance from the sampling point to the detection point) to obtain the current surface height h.
[0028] In step S4, the scanning path of the laser etching pattern can adopt various strategies such as straight line scanning, loop filling, and partitioned spiral filling.
[0029] The working principle of this invention is as follows: Figure 2 When an industrial microscope camera is aimed at the observation position in the laser etching area scanned by a galvanometer, and the coaxial indicator light of the laser is turned on, the position (x, y) of the light spot on the surface of the part at different heights h will change accordingly. Through height calibration experiments, a mapping table between the center coordinates (x, y) of the light spot in the image acquired by the microscope camera and the surface height h is established, such as... Figure 2 The table on the right is stored in the computer's memory.
[0030] Laser etching process flow chart as follows Figure 3 The control software detects the coordinates (x0, y0) of the laser spot on the part surface using a microscope camera, then calls a pre-calibrated height mapping table in the computer memory and calculates the initial height h0 of the part surface through interpolation. The control software controls the galvanometer to scan the laser according to the set processing pattern and process parameters to perform one laser etching process. Then, the control software turns on the coaxial indicator light of the laser and detects the coordinates (xi, yi) of the laser spot on the part surface using a microscope camera, calculates the corresponding height hi, and obtains the etching depth value Δh = hi - h0. In S6, the control software determines whether the etching depth value Δh has reached the set processing depth d. If it has not reached the processing depth d, it returns to S4 to continue processing. If it has reached the processing depth d, the processing is completed.
[0031] A galvanometer scanning laser precision etching apparatus with machine vision measurement feedback is applied to the aforementioned machine vision measurement feedback galvanometer scanning laser precision etching method. The machine vision measurement feedback galvanometer scanning laser precision etching apparatus is as follows: Figure 1 As shown, the laser 2 can be a fiber laser or a gas laser. The laser 2 can not only emit high-energy processing lasers, but also integrates a coaxial indicating laser. The control software can freely select and control the emission of the laser beam according to the processing and measurement needs. The laser 2 and the galvanometer 3 are connected through a fixed spatial optical path or fiber optical path. The microscope camera 4 can be fixedly connected to the galvanometer 3 through a mounting bracket, or placed above the side of the etching area to be observed through an independent bracket.
[0032] Specifically, the control computer 1 is connected to the laser 2, galvanometer 3, and microscope camera 4 via signal lines. The control computer 1 is equipped with self-developed control software, which can control the laser 2's switching and power parameters, as well as the galvanometer's scanning motion. The microscope camera 4 is a fixed-focus or variable-focus industrial CCD or CMOS microscope camera with millions of pixels or higher. By selecting different magnification objectives and eyepieces, the microscope camera 4's pixel resolution can reach micrometer or sub-micrometer accuracy. The control software has the function of controlling the microscope camera 4 to acquire images and can identify the position of the light spot in the image through machine vision algorithms. The control software has machine vision measurement capabilities. The laser 2 can emit not only high-energy processing lasers but also coaxial indicating lasers. The control software can freely select and control the laser beam emission according to processing and measurement needs. The center of the light spot acquired and identified by the microscope camera 4 can be either the laser spot or the processing laser spot. The galvanometer can be an industrial 2D or 3D galvanometer.
[0033] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of the claims of the present invention.
Claims
1. A galvanometer scanning laser precision etching method with machine vision measurement feedback, characterized in that, Includes the following steps: S1. Align the industrial microscope camera with the observation position of the laser etching processing area scanned by the galvanometer, turn on the coaxial indicator light of the laser, and establish a mapping table between the center coordinates (x, y) of the spot of the image acquired by the microscope camera and the surface height h through a height calibration experiment, and store it in the computer memory. S2. Before starting laser etching, set the processing depth d of the graphic to be processed in the control software on the computer. S3. The control software turns on the coaxial indicator light of the laser. The control software detects the center coordinates (x0, y0) of the light spot on the surface of the part through a microscope camera. Then, it calls the pre-calibrated height mapping table in the computer memory and calculates the initial height h0 of the surface of the part through interpolation. S4. The control software controls the galvanometer to scan the laser according to the set processing pattern and process parameters to perform one laser etching process. S5. The control software turns on the coaxial indicator light of the laser. The control software detects the center coordinates (xi,yi) of the light spot on the surface of the part through a microscope camera, calculates the corresponding height hi, and obtains the etching depth value Δh=hi-h0; S6. The control software determines whether the etching depth value Δh has reached the set processing depth d. If the processing depth d has not been reached, it returns to S4 to continue processing. If the processing depth d has been reached, the processing is complete.
2. The galvanometer scanning laser precision etching method with machine vision measurement feedback according to claim 1, characterized in that, In step S1, the height calibration experiment is as follows: standard gauge blocks of different heights h that have been certified by metrology are placed in the processing area. The control software collects the light spots on the surface of the standard gauge blocks through a microscope camera and obtains the pixel coordinates (x, y) of the center of the light spots through a visual recognition algorithm, thereby establishing a one-to-one correspondence mapping table between the center coordinates (x, y) of the light spots and the surface height h, and storing it in the computer memory.
3. The galvanometer scanning laser precision etching method with machine vision measurement feedback according to claim 1, characterized in that, In step S1, after the control software acquires the light spot image through the industrial microscope camera, the control software executes the image processing algorithm to obtain the pixel coordinates (x, y) of the light spot center.
4. The galvanometer scanning laser precision etching method with machine vision measurement feedback according to claim 1, characterized in that, In step S3, the interpolation calculation employs commonly used linear interpolation algorithms, quadratic interpolation algorithms, and cubic interpolation algorithms.
5. The galvanometer scanning laser precision etching method with machine vision measurement feedback according to claim 1, characterized in that, In step S4, the scanning path of the laser etching pattern adopts multiple strategies such as straight line scanning, loop filling, and partitioned spiral filling.
6. A galvanometer scanning laser precision etching apparatus with machine vision measurement feedback, applied to the galvanometer scanning laser precision etching method with machine vision measurement feedback as described in any one of claims 1-5, characterized in that, The machine vision measurement feedback galvanometer scanning laser precision etching device uses a fiber laser or a gas laser. The laser not only emits high-energy processing lasers but also integrates a coaxial indicating laser. The control software can freely select and control the laser beam emission according to processing and measurement needs. The laser and galvanometer are connected through a fixed spatial optical path or fiber optical path. The microscope camera is fixedly connected to the galvanometer via a mounting bracket or placed above the area to be etched via an independent bracket.
7. The galvanometer scanning laser precision etching apparatus for machine vision measurement feedback according to claim 6, characterized in that, The control computer is connected to the laser, galvanometer, and microscope camera via signal lines. The control computer is equipped with self-developed control software that can control the laser's on / off state, power and process parameters, as well as the galvanometer's scanning motion. The microscope camera is a fixed-focus or variable-focus industrial CCD or CMOS microscope camera with millions of pixels or higher. By selecting different magnification objectives and eyepieces, the microscope camera's pixel resolution can reach micrometer or sub-micrometer precision.
8. The galvanometer scanning laser precision etching apparatus for machine vision measurement feedback according to claim 7, characterized in that, The control software has the function of controlling the microscope camera to acquire images, and can identify the center position of the light spot in the image through machine vision algorithms.
9. The galvanometer scanning laser precision etching apparatus for machine vision measurement feedback according to claim 8, characterized in that, The control software acquires images through a microscope camera and identifies the center of the laser spot, which is used as an indicator laser spot or a processing laser spot.
10. The galvanometer scanning laser precision etching apparatus for machine vision measurement feedback according to claim 9, characterized in that, The galvanometer should be an industrial 2D or 3D galvanometer.