Method for processing marking depth problem of laser marking equipment

Abstract

The invention discloses a method for processing the marking depth problem of laser marking equipment. The method comprises the steps of optimizing an optical system design, constructing an automatic equipment calibration process, strengthening the environmental adaptability of the equipment, optimizing a control algorithm to be matched with an industrial application scene, processing the problem of inconsistent marking depth, monitoring and adjusting the direction and path of a laser beam in real time and the like. A flat-topped beam converter, an aspherical lens, a temperature-controllable optical platform and other optimized optical systems are combined with a high-precision camera, a sensor, an algorithm and the like to realize real-time monitoring and dynamic adjustment of a reflector angle, a laser track, environmental parameters, a marking path, power and the like, so that the laser marking depth is consistent, the direction is accurate, the path is not inclined, and the laser marking quality is improved. The machining precision and stability of the laser marking equipment are improved, and the laser marking equipment is suitable for different materials and process requirements.

Description

Technical Field

[0001] The invention relates to the technical field of laser processing, and in particular to a method for processing a problem of marking depth of a laser marking device. Background Art

[0002] In the current laser processing field, laser marking technology is widely used due to its advantages of high precision, high efficiency and non-contact processing. However, in the actual laser marking process, problems such as inconsistent marking depth and skew often occur, which seriously affects the marking quality and product consistency.

[0003] In terms of the optical system of existing laser marking equipment, the beam energy distribution is uneven, the energy attenuation at the edge of the spot is large, and the temperature fluctuation has a significant impact on the optical elements and the laser beam, resulting in unstable marking effects. In terms of equipment calibration, the lack of high-precision monitoring means and real-time and effective calibration algorithms makes the reflector angle adjustment untimely and inaccurate, thereby affecting the laser trajectory and causing skewed marking. In terms of environmental adaptability, the built-in environmental sensing module of existing equipment is not accurate enough to accurately perceive environmental changes, nor can it dynamically adjust the laser output parameters in time, making it difficult to ensure production stability. In terms of control algorithms, the adaptability to industrial application scenarios is poor, and it is impossible to accurately analyze the error trend in the production process, and it is impossible to dynamically optimize the marking path and power distribution, making it difficult to meet the needs of different materials and processes.

[0004] In dealing with the problem of inconsistent marking depth, the existing method usually uses fixed laser power and focus position, which cannot be dynamically adjusted according to actual conditions, resulting in inconsistent marking depth and affecting product quality. In summary, the existing laser marking equipment and technology have deficiencies in many aspects and cannot effectively solve problems such as inconsistent marking depth and skewness. A new processing method is urgently needed to improve the performance of laser marking equipment and marking quality. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a method for processing the depth problem of laser marking equipment, and the specific steps are as follows:

[0006] Step 1: Ensure uniform energy distribution of the laser beam through flat-top beam converter beam shaping technology; use aspheric lens optical elements to reduce energy attenuation at the edge of the spot; build a temperature-controllable optical platform to reduce the impact of temperature fluctuations on optical elements and laser beams;

[0007] Step 2: Monitor the reflector angle and laser trajectory through a high-precision camera, and adjust the reflector position in real time in combination with a calibration algorithm;

[0008] Step 3: Install a temperature and humidity sensor in the equipment’s built-in environmental sensing module to dynamically adjust the laser output parameters according to environmental changes to ensure production stability;

[0009] Step 4: Use algorithms to analyze the error trend in the production process, dynamically optimize the marking path and power distribution, and adapt to different materials and process requirements;

[0010] Step 5: When dealing with the problem of inconsistent marking depth, ensure the consistency of marking depth by dynamically adjusting the laser power and focus position;

[0011] Step 6: The direction of the laser beam is monitored in real time through a high-precision camera and reflector angle monitoring system; when the laser beam direction is detected to be offset, the system automatically adjusts the angle of the reflector to ensure that the laser beam direction is consistent with the processing path.

[0012] As a further improvement of the present invention, step 1 can be described as:

[0013] The flat-top beam converter converts the original Gaussian laser beam into a flat-top beam with uniform energy distribution through a special optical design. Multiple aspheric lenses are arranged to form a synthetic beam shaping device. Each lens deforms the beam to a certain extent through refraction, focal length change, etc., and finally combines into a uniform flat-top beam. The component material of the beam shaper is quartz glass, which can effectively withstand high-energy laser beams, especially in the UV and IR bands. The flat-top beam converter is installed at the output end of the laser, at the starting position of the entire optical path. During the installation process, ensure that the optical axis of the beam shaper is aligned with the optical axis of the laser light source to avoid deviation of the beam from the target or unevenness due to alignment errors. At the same time, the polarizer and grating are used to control the directionality and stability of the beam. The polarization state of the beam is effectively controlled by the polarizer, and the directional stability and processing accuracy of the laser beam are improved by the characteristics of polarized light. degree; the grating performs wavelength selection and dispersion separation on the light beam, and effectively controls the propagation direction and energy distribution of the light beam by adjusting the angle and arrangement of the grating; the temperature control system of the optical platform reduces the impact of temperature fluctuations on optical components and laser beams by accurately regulating the platform temperature; the temperature control system adopts a method of combining a thermoelectric cooling module with a heating wire; the thermoelectric cooling module quickly adjusts the temperature according to the sensor feedback to ensure that the platform temperature is stable within the set range; the temperature control system uses high-efficiency thermal conductive materials to ensure that heat can be quickly and evenly distributed to the entire platform to avoid excessive local temperature differences; the temperature control equipment is integrated at the bottom of the optical platform and closely matches the platform structure; the temperature control system and the sensor are combined to form a closed-loop feedback mechanism, which monitors the platform temperature changes in real time and dynamically adjusts the working status of the heating and cooling equipment to ensure that the platform is always in the most suitable temperature range to meet the needs of high-precision laser processing.

[0014] As a further improvement of the present invention, the real-time adjustment of the reflector position in step 2 can be expressed as:

[0015] Step 2.1: Image acquisition and camera model

[0016] The image data of the reflector and laser beam is captured in real time by a high-precision camera. The camera projects the object in the three-dimensional world coordinate system onto the two-dimensional image plane. Let the coordinates of the object in the three-dimensional world be (X, Y, Z), and the corresponding image coordinates be (x, y), which can be calculated using the following projection equation:

[0017]

[0018] Among them, K is the intrinsic parameter matrix of the camera, which represents the focal length and principal point coordinates; the specific form is:

[0019]

[0020] Among them, f x and f y is the focal length of the camera in the x and y directions, c x and c y is the coordinate of the optical center of the camera, and the coordinates of the reflector and laser beam in the three-dimensional space are projected onto the two-dimensional image plane through the projection model;

[0021] Step 2.2 Image processing and feature extraction

[0022] After the image data is collected, the Canny edge detection algorithm is used to extract the important feature edges in the image. The formula is as follows:

[0023]

[0024] Among them, G x and G y are the gradients of the image in the x and y directions, respectively, and I represents the image intensity. By calculating the gradient of the image, the edge position of the laser beam in the image is determined, and then the center of the laser beam in the image is extracted through algorithms such as SIFT and Harris corner detection.

[0025] Step 2.3 Coordinate transformation and error calculation

[0026] The key feature mirror position or laser beam center in the image needs to be matched with the actual position in the world coordinate system; therefore, the image coordinates need to be converted back to the actual physical coordinates and the deviation needs to be calculated;

[0027] Let the coordinates of a point in the image be (x measured ,y measured ), the world coordinates (X world ,Y world,Z world ); In order to perform accurate calibration, the calibration board is used to calibrate the camera's external parameters: rotation matrix and translation vector, and the image coordinates are converted to world coordinates using the following formula:

[0028]

[0029] Among them, R is the rotation matrix of the camera, and T is the translation vector;

[0030] After obtaining the world coordinates, calculate the deviation between the image coordinates and the real coordinates; let the ideal coordinates of the target reflector position be (X ideal ,Y ideal ,Z ideal ), the actual measured coordinates are (X measured ,Y measured ,Z measured ), the position error ΔE is:

[0031]

[0032] This error represents the positioning error of the reflector, and the goal is to make this error as close to zero as possible;

[0033] Adjust the mirror position in step 2.4

[0034] Through the above steps, the error of the reflector or laser beam position can be obtained; the error value is input into the feedback system in real time to adjust the reflector, and the output u(t) of the PID controller is used to adjust the position of the reflector. The formula is as follows:

[0035]

[0036] Among them, E target is the target error, E current is the current error, u(t) is the control signal, K p , K i , K d They are proportional, integral and differential gains of PID control respectively; by controlling the position of the reflector through the PID control system, the deviation of the reflector will be corrected.

[0037] As a further improvement of the present invention, the process of dynamically adjusting the laser output parameters in step 4 can be expressed as follows:

[0038] Step 3.1 Environmental monitoring and modeling

[0039] An environmental sensing module is integrated inside the device, including a temperature and humidity sensor, to obtain environmental parameters in real time. The temperature and humidity sensor reading is set as T measured , H measured,Combined with sensor data, a model of the impact of environmental changes on laser processing is established, including: ,the impact of temperature and humidity changes on the transmission efficiency of laser power P;

[0040] Through experimental data and least squares fitting, the function of laser power loss ΔP and frequency loss Δf is defined as:

[0041] ΔP=f(T,H)

[0042] Where T is the ambient temperature, H is the relative humidity, and f() is the fitting function of the least squares and experimental data;

[0043] Step 3.2 Dynamically adjust laser output parameters

[0044] In order to compensate for the influence of environmental changes on the laser output power, the laser power P and frequency f are adjusted in real time; let the ideal laser power and frequency be P ideal and f ideal , the laser power after dynamic adjustment P adjusted and frequency f adjusted The output parameters are:

[0045] P adjusted =P ideal +ΔP

[0046] f adjusted =f ideal +Δf

[0047] By adjusting P adjusted and f adjusted , ensuring the stability and consistency of laser beam energy and reducing the impact of environmental fluctuations.

[0048] As a further improvement of the present invention, the process of dynamically optimizing the marking path and power distribution in step 4 can be expressed as follows:

[0049] Step 4.1: Path error modeling and real-time feedback

[0050] Step 4.1.1 Path Error Definition

[0051] The path error measures the deviation between the ideal path and the actual processing path. The formula is as follows:

[0052] e path (t) = r ideal (t)-r actual (t)

[0053] Among them, t is the time variable, e path (t) is the path error vector; r ideal (t) is the ideal path, which is determined in advance by CAD design or planning algorithm, r ideal (t) The vector is represented as follows:

[0054] r ideal (t) = [x ideal (t),y ideal (t),z ideal (t)] T

[0055] Among them, x ideal (t), y ideal (t), z ideal (t) are the coordinates of the ideal path on the x, y, and z axes respectively;

[0056] r actual (t) is the actual path, obtained by the measurement system, r actual (t) The vector is represented as follows:

[0057] r actual (t) = [x actual (t),y actual (t),z actual (t)] T

[0058] Step 4.1.2 Acquisition of measurement variables

[0059] The processing path coordinates are acquired in real time through a high-precision laser rangefinder, an inertial measurement unit, and a machine vision system: the laser rangefinder is used to measure the distance between the laser focus and the processing plane to obtain z actual (t); The visual system collects the image of the processed surface through the camera and calculates x actual (t) and y actual (t);

[0060] Step 4.2: Real-time path correction

[0061] Step 4.2.1 The goal of the revision is to optimize the path r corrected (t), so that it is as close as possible to the ideal path r ideal (t);

[0062] The optimization objective function is:

[0063]

[0064] Where, T is the integration time;

[0065] Step 4.2.2 Path correction calculation, correction formula:

[0066] r corrected (t) = r actual (t)+k path ·e path (t)

[0067] Among them, r corrected (t) is the corrected path coordinate; k path is the path correction gain coefficient, which is used to adjust the correction amplitude; e path (t) is the path error, calculated by step 4.1;

[0068] Step 4.2.3 Path smoothing

[0069] To avoid oscillations or sharp corners in the correction path, smooth it using a Bezier curve:

[0070]

[0071] Among them, r smooth (t) is the smoothed path, r i To correct the path r corrected (t) is the control point on the curve, i is the order variable, and n is the order of the Bezier curve. is the Bezier curve basis function:

[0072]

[0073] Step 4.3: Comprehensive optimization path execution, the optimization path r smooth (t) is input to the controller and transmitted to the motion controller to control the movement of the laser head; the controller calculates the driving signal of the motor according to the corrected path so that the laser head follows the corrected path.

[0074] As a further improvement of the present invention, the process of processing the problem of inconsistent marking depth in step 5 can be expressed as follows:

[0075] Step 5.1 Dynamic adjustment of laser power

[0076] Step 5.1.1 Laser power monitoring and feedback

[0077] To ensure the consistency of marking depth, the system monitors the laser power output in real time and makes dynamic adjustments based on material characteristics and processing requirements. The laser power sensor monitors the laser output power in real time to ensure that the power value fluctuates within the set range. When it is detected that the laser power fluctuation exceeds the allowable range, the system automatically adjusts the laser output power to ensure power stability.

[0078] Step 5.1.2 Power Adjustment Algorithm

[0079] In order to dynamically adjust the laser power, let the ideal laser power be P ideal , the actual measured laser power is P actual , then the power error ΔP is:

[0080] ΔP=P ideal-P actual

[0081] According to the power error, the system adjusts the laser power P by the following formula adjusted :

[0082] P adjusted =P actual +K p ΔP

[0083] Among them, K p It is the proportional coefficient of power adjustment, used to control the adjustment range;

[0084] Step 5.1.3 Material property adaptation. Different materials have different absorption rates for lasers. The system will automatically adjust the laser power according to the characteristics of the material. For materials with high absorption rates, the system will appropriately reduce the laser power to avoid marking too deep. For materials with low absorption rates, the system will increase the laser power to ensure sufficient marking depth.

[0085] Step 5.2 Focus position calibration

[0086] Step 5.2.1 Focus position monitoring: the system uses a high-precision laser rangefinder to monitor the distance between the laser focus and the processing plane in real time. The laser rangefinder is installed on the laser head and measures the distance d between the laser focus and the processing plane in real time. Let the ideal focus position be d ideal , the actual measured focal position is d actual , then the focus error Δd is:

[0087] Δd=d ideal -d actual

[0088] Step 5.2.2 Focus position adjustment: When the focus position is detected to be offset, the system will automatically adjust the position of the laser head to ensure that the focus position remains at the optimal position; according to the focus error, the system adjusts the position of the laser head by the following formula d adjusted :

[0089] d adjusted =d actual +K d ·Δd

[0090] Among them, K d The proportional coefficient for adjusting the focus position, used to control the adjustment amplitude.

[0091] As a further improvement of the present invention, the process of the laser beam direction deviation problem in step 6 can be expressed as follows:

[0092] Step 6.1 Laser beam direction calibration

[0093] Step 6.1.1 Laser beam direction monitoring

[0094] The direction of the laser beam is monitored in real time through a high-precision camera and a reflector angle monitoring system. When the laser beam direction is detected to be offset, the system automatically adjusts the angle of the reflector to ensure that the laser beam direction is consistent with the processing path. The high-precision camera captures the image of the laser beam in real time and extracts the center position of the laser beam through an image processing algorithm. The angle sensor monitors the angle of the reflector in real time to ensure that the angle of the reflector is within the set range.

[0095] Step 6.1.2 Direction error calculation

[0096] Let the direction of the ideal laser beam be θ ideal , the actual measured laser beam direction is θ actual , then the direction error Δθ is:

[0097] Δθ=θ ideal -θ actual

[0098] Step 6.1.3 Reflector Angle Adjustment

[0099] When the laser beam direction is detected to be offset, the system automatically adjusts the angle of the reflector to ensure that the laser beam direction is consistent with the processing path; according to the direction error, the system adjusts the angle θ of the reflector by the following formula adjusted :

[0100] θ adjusted =θ actual +K θ ·Δθ

[0101] Among them, K θ It is the proportional coefficient of the reflector angle adjustment, used to control the adjustment range;

[0102] Step 6.2 Path correction and feedback

[0103] Step 6.2.1 Path error monitoring

[0104] The processing path coordinates are acquired in real time through high-precision laser rangefinder, inertial measurement unit and vision system to ensure the accuracy of the processing path; the laser rangefinder is used to measure the distance between the laser focus and the processing plane; the vision system collects the processing surface image through the camera and calculates the coordinates of the processing path;

[0105] Step 6.2.2 Path error calculation

[0106] Let the ideal path be P ideal , the actual measured path is P actual , then the path error ΔP is:

[0107] ΔP=P ideal -P actual

[0108] Step 6.2.3 Path Correction Algorithm

[0109] When path deviation is detected, the system automatically corrects the path to ensure that the marking is not skewed; according to the path error, the system corrects the path P by the following formula adjusted :

[0110] P adjusted =P actual +K P ΔP

[0111] Among them, K P is the proportional coefficient of path correction, which is used to control the correction amplitude;

[0112] 6.2.4 Path Smoothing

[0113] To avoid oscillation or sharp corners in the correction path, the system smoothes the path using Bezier curves to ensure smooth movement of the laser head.

[0114] The present invention provides a method for processing the problem of depth of marking by a laser marking device, and the beneficial effect is as follows:

[0115] 1. The present invention optimizes the optical system design, adopts a flat-top beam converter, an aspheric lens and a temperature-controllable optical platform, ensures uniform energy distribution of the laser beam, reduces energy attenuation at the edge of the spot, reduces the impact of temperature fluctuations, significantly improves marking accuracy and stability, and makes the marking effect more uniform and consistent.

[0116] 2. The present invention constructs an automated equipment calibration process, uses a high-precision camera to monitor the reflector angle and laser trajectory, and combines the calibration algorithm to adjust the reflector position in real time, effectively solving the problem of skewed marking and improving the accuracy and reliability of marking.

[0117] 3. When dealing with the problem of inconsistent marking depth, the present invention ensures the consistency of marking depth by dynamically adjusting the laser power and focal position, thereby improving the quality and aesthetics of the product. By real-time monitoring and adjusting the direction and path of the laser beam, the marking accuracy is further improved, the defective rate is reduced, the production cost is reduced, and the competitiveness of the product in the market is enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0118] Figure 1 is a flow chart of the present invention;

[0119] Figure 2 is a flow chart of path correction of the present invention;

[0120] Figure 3 It is a diagram of the actual production situation of the present invention. DETAILED DESCRIPTION

[0121] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0122] The present invention optimizes the optical system by using a flat-top beam converter to ensure uniform energy distribution. Figure 3 As shown, a high-precision calibration process is constructed to adjust the position of the reflector in real time. The built-in environmental sensing module adapts to environmental changes and optimizes the control algorithm to adapt to different scenarios. The laser power and focus position are dynamically adjusted to ensure consistent marking depth. The invention flowchart is shown below: Figure 1 shown.

[0123] Step 1: Optimize the optical system design

[0124] The flat-top beam converter beam shaping technology is used to ensure uniform energy distribution of the laser beam; aspheric lens optical elements are used to reduce energy attenuation at the edge of the light spot; a temperature-controllable optical platform is built to reduce the impact of temperature fluctuations on optical elements and laser beams.

[0125] The flat-top beam converter converts the original Gaussian laser beam into a flat-top beam with uniform energy distribution through a special optical design, and arranges multiple aspheric lenses to form a synthetic beam shaping device. Each lens deforms the beam to a certain extent through refraction, focal length change, etc., and finally combines into a uniform flat-top beam. The component material of the beam shaper is quartz glass, which can effectively withstand high-energy laser beams, especially in the UV and IR bands. The flat-top beam converter is installed at the output end of the laser, at the starting position of the entire optical path. During the installation process, ensure that the optical axis of the beam shaper is aligned with the optical axis of the laser light source to avoid the beam from deviating from the target or unevenness due to alignment errors. At the same time, the polarizer and grating are used to control the directionality and stability of the beam. The polarization state of the beam is effectively controlled by the polarizer, and the directional stability and processing accuracy of the laser beam are improved by the characteristics of polarized light. The grating selects the wavelength and disperses the beam. By adjusting the angle and arrangement of the grating, the propagation direction and energy distribution of the beam are effectively controlled.

[0126] The temperature control system of the optical platform reduces the impact of temperature fluctuations on optical components and laser beams by precisely controlling the platform temperature. The temperature control system uses a combination of thermoelectric cooling modules and heating wires. The thermoelectric cooling modules quickly adjust the temperature based on sensor feedback to ensure that the platform temperature is stable within the set range. The temperature control system uses high-efficiency thermal conductive materials to ensure that heat can be quickly and evenly distributed to the entire platform to avoid excessive local temperature differences. The temperature control equipment is integrated at the bottom of the optical platform and fits closely with the platform structure. The temperature control system and sensors are combined to form a closed-loop feedback mechanism. By real-time monitoring of platform temperature changes, the working status of the heating and cooling equipment is dynamically adjusted to ensure that the platform is always in the most suitable temperature range to meet the needs of high-precision laser processing.

[0127] Step 2: Build an automated equipment calibration process

[0128] The reflector angle and laser trajectory are monitored by a high-precision camera, and the reflector position is adjusted in real time in combination with a calibration algorithm.

[0129] Step 2.1: Image acquisition and camera model

[0130] The image data of the reflector and laser beam is captured in real time by a high-precision camera. The camera projects the object in the three-dimensional world coordinate system onto the two-dimensional image plane. Let the coordinates of the object in the three-dimensional world be (X, Y, Z), and the corresponding image coordinates be (x, y), which can be calculated using the following projection equation:

[0131]

[0132] Among them, K is the camera's internal parameter matrix, which represents the focal length and principal point coordinates. The specific form is:

[0133]

[0134] Among them, f x and f y is the focal length of the camera in the x and y directions, c x and c y is the coordinate of the optical center of the camera, and the coordinates of the reflector and laser beam in the three-dimensional space are projected onto the two-dimensional image plane through the projection model.

[0135] Step 2.2 Image processing and feature extraction

[0136] After the image data is collected, the Canny edge detection algorithm is used to extract the important feature edges in the image. The formula is as follows:

[0137]

[0138] Among them, G x and G yare the gradients of the image in the x and y directions, respectively, and I represents the image intensity. By calculating the gradient of the image, the edge position of the laser beam in the image is determined, and then the center of the laser beam in the image is extracted through algorithms such as SIFT and Harris corner detection.

[0139] Step 2.3 Coordinate transformation and error calculation

[0140] The key feature mirror position or laser beam center in the image needs to be matched with the actual position in the world coordinate system. Therefore, the image coordinates need to be converted back to the actual physical coordinates and the deviation needs to be calculated.

[0141] Let the coordinates of a point in the image be (x measured ,y measured ), the world coordinates (X world ,Y world ,Z world ). In order to perform accurate calibration, a calibration board is used to calibrate the camera's external parameters: rotation matrix and translation vector, and the image coordinates are converted to world coordinates using the following formula:

[0142]

[0143] Where R is the rotation matrix of the camera and T is the translation vector.

[0144] After obtaining the world coordinates, calculate the deviation between the image coordinates and the real coordinates. Let the ideal coordinates of the target reflector position be (X ideal ,Y ideal ,Z ideal ), the actual measured coordinates are (X measured ,Y measured ,Z measured ), the position error ΔE is:

[0145]

[0146] This error represents the positioning error of the mirror, and the goal is to make this error as close to zero as possible.

[0147] Adjust the mirror position in step 2.4

[0148] Through the above steps, the error of the reflector or laser beam position can be obtained. The error value is input into the feedback system in real time to adjust the reflector, and the output u(t) of the PID controller is used to adjust the position of the reflector. The formula is as follows:

[0149]

[0150] Among them, E target is the target error, Ecurrent is the current error, u(t) is the control signal, K p , K i , K d They are proportional, integral and differential gains of PID control. By controlling the position of the reflector through the PID control system, the deviation of the reflector will be corrected.

[0151] Step 3: Enhance equipment environmental adaptability

[0152] The device has a built-in environmental sensing module with temperature and humidity sensors to dynamically adjust laser output parameters based on environmental changes to ensure production stability.

[0153] Step 3.1 Environmental monitoring and modeling

[0154] An environmental sensing module is integrated inside the device, including a temperature and humidity sensor, to obtain environmental parameters in real time. Assume that the temperature and humidity sensor reading is T measured , H measured ,Combined with sensor data, a model of the impact of environmental changes on laser processing is established, including: ,The transmission efficiency of laser power P affected by changes in temperature and humidity.

[0155] Through experimental data and least squares fitting, the function of laser power loss ΔP and frequency loss Δf is defined as:

[0156] ΔP=f(T,H)

[0157] Where T is the ambient temperature, H is the relative humidity, and f() is the fitting function of the least squares and experimental data.

[0158] Step 3.2 Dynamically adjust laser output parameters

[0159] To compensate for the impact of environmental changes on the laser output power, the laser power P and frequency f are adjusted in real time. Let the ideal laser power and frequency be P ideal and f ideal , the laser power after dynamic adjustment P adjusted and frequency f adjusted The output parameters are:

[0160] P adjusted =P ideal +ΔP

[0161] f adjusted =f ideal +Δf

[0162] By adjusting P adjusted and f adjusted , ensuring the stability and consistency of laser beam energy and reducing the impact of environmental fluctuations.

[0163] Step 4: Optimize control algorithms to suit industrial application scenarios

[0164] Use algorithms to analyze the error trend in the production process, dynamically optimize the marking path and power distribution, and adapt to different materials and process requirements. The path correction flow chart is as follows: Figure 2 shown.

[0165] Step 4.1: Path error modeling and real-time feedback

[0166] Step 4.1.1 Path Error Definition

[0167] The path error measures the deviation between the ideal path and the actual processing path. The formula is as follows:

[0168] e path (t) = r ideal (t)-r actual (t)

[0169] Among them, t is the time variable, e path (t) is the path error vector; r ideal (t) is the ideal path, which is determined in advance by CAD design or planning algorithm, r ideal (t) The vector is represented as follows:

[0170] r ideal (t) = [x ideal (t),y ideal (t),z ideal (t)] T

[0171] Among them, x ideal (t), y ideal (t), z ideal (t) are the coordinates of the ideal path on the x, y, and z axes respectively.

[0172] r actual (t) is the actual path, obtained by the measurement system, r actual (t) The vector is represented as follows:

[0173] r actual (t) = [x actual (t),y actual (t),z actual (t)] T

[0174] Step 4.1.2 Acquisition of measurement variables

[0175] The processing path coordinates are acquired in real time through a high-precision laser rangefinder, an inertial measurement unit, and a machine vision system: the laser rangefinder is used to measure the distance between the laser focus and the processing plane to obtain z actual(t); The visual system collects the image of the processed surface through the camera and calculates x actual (t) and y actual (t).

[0176] Step 4.2: Real-time path correction

[0177] Step 4.2.1 The goal of the revision is to optimize the path r corrected (t), so that it is as close as possible to the ideal path r ideal (t).

[0178] The optimization objective function is:

[0179]

[0180] Where T is the integration time.

[0181] Step 4.2.2 Path correction calculation, correction formula:

[0182] r corrected (t) = r actual (t)+k path ·e path (t)

[0183] Among them, r corrected (t) is the corrected path coordinate; k path is the path correction gain coefficient, which is used to adjust the correction amplitude; e path (t) is the path error, calculated in step 4.1.

[0184] Step 4.2.3 Path smoothing

[0185] To avoid oscillations or sharp corners in the correction path, smooth it using a Bezier curve:

[0186]

[0187] Among them, r smooth (t) is the smoothed path, r i To correct the path r corrected (t) is the control point on the curve, i is the order variable, and n is the order of the Bezier curve. is the Bezier curve basis function:

[0188]

[0189] Step 4.3: Comprehensive optimization path execution, the optimization path r smooth (t) is input to the controller and transmitted to the motion controller to control the movement of the laser head; the controller calculates the driving signal of the motor according to the corrected path so that the laser head follows the corrected path.

[0190] Step 5: When dealing with inconsistent marking depth, dynamically adjust the laser power and focus position to ensure consistency in marking depth.

[0191] Step 5.1 Dynamic adjustment of laser power

[0192] Step 5.1.1 Laser power monitoring and feedback

[0193] To ensure the consistency of marking depth, the system monitors the laser power output in real time and makes dynamic adjustments based on material characteristics and processing requirements. The laser power sensor monitors the laser output power in real time to ensure that the power value fluctuates within the set range. When it is detected that the laser power fluctuation exceeds the allowable range, the system automatically adjusts the laser output power to ensure power stability.

[0194] Step 5.1.2 Power Adjustment Algorithm

[0195] In order to dynamically adjust the laser power, let the ideal laser power be P ideal , the actual measured laser power is P actual , then the power error ΔP is:

[0196] ΔP=P ideal -P actual

[0197] According to the power error, the system adjusts the laser power P by the following formula adjusted :

[0198] P adjusted =P actual +K p ΔP

[0199] Among them, K p It is the proportional coefficient of power adjustment, which is used to control the adjustment range.

[0200] Step 5.1.3 Material property adaptation: Different materials have different absorption rates for lasers, and the system will automatically adjust the laser power according to the characteristics of the material. For materials with high absorption rates, the system appropriately reduces the laser power to avoid marking too deep; for materials with low absorption rates, the system increases the laser power to ensure sufficient marking depth.

[0201] Step 5.2 Focus position calibration

[0202] Step 5.2.1 Focus position monitoring: The system uses a high-precision laser rangefinder to monitor the distance between the laser focus and the processing plane in real time. The laser rangefinder is installed on the laser head and measures the distance d between the laser focus and the processing plane in real time. Let the ideal focus position be d ideal , the actual measured focal position is d actual , then the focus error Δd is:

[0203] Δd=d ideal -d actual

[0204] Step 5.2.2 Focus position adjustment: When the focus position is detected to be offset, the system will automatically adjust the position of the laser head to ensure that the focus position remains at the optimal position. According to the focus error, the system adjusts the position of the laser head by the following formula: adjusted :

[0205] d adjusted =d actual +K d ·Δd

[0206] Among them, K d The proportional coefficient for adjusting the focus position, used to control the adjustment amplitude.

[0207] Step 6: The direction of the laser beam is monitored in real time through a high-precision camera and reflector angle monitoring system. When the laser beam direction is detected to be offset, the system automatically adjusts the angle of the reflector to ensure that the laser beam direction is consistent with the processing path.

[0208] Step 6.1 Laser beam direction calibration

[0209] Step 6.1.1 Laser beam direction monitoring

[0210] The direction of the laser beam is monitored in real time through a high-precision camera and reflector angle monitoring system. When the laser beam direction is detected to be offset, the system automatically adjusts the angle of the reflector to ensure that the laser beam direction is consistent with the processing path. The high-precision camera captures the image of the laser beam in real time and extracts the center position of the laser beam through an image processing algorithm. The angle sensor monitors the angle of the reflector in real time to ensure that the angle of the reflector is within the set range.

[0211] Step 6.1.2 Direction error calculation

[0212] Let the direction of the ideal laser beam be θ ideal , the actual measured laser beam direction is θ actual , then the direction error Δθ is:

[0213] Δθ=θ ideal -θ actual

[0214] Step 6.1.3 Reflector Angle Adjustment

[0215] When the laser beam direction is detected to be offset, the system automatically adjusts the angle of the reflector to ensure that the laser beam direction is consistent with the processing path. According to the direction error, the system adjusts the angle θ of the reflector by the following formula adjusted :

[0216] θ adjusted =θ actual +K θ ·Δθ

[0217] Among them, K θ It is the proportional coefficient of the reflector angle adjustment, used to control the adjustment amplitude.

[0218] Step 6.2 Path correction and feedback

[0219] Step 6.2.1 Path error monitoring

[0220] The processing path coordinates are acquired in real time through high-precision laser rangefinder, inertial measurement unit and vision system to ensure the accuracy of the processing path. The laser rangefinder is used to measure the distance between the laser focus and the processing plane. The vision system collects the processing surface image through the camera and calculates the coordinates of the processing path.

[0221] Step 6.2.2 Path error calculation

[0222] Let the ideal path be P ideal , the actual measured path is P actual , then the path error ΔP is:

[0223] ΔP=P ideal -P actual

[0224] Step 6.2.3 Path Correction Algorithm

[0225] When path deviation is detected, the system automatically corrects the path to ensure that the marking is not skewed. According to the path error, the system corrects the path P by the following formula adjusted :

[0226] P adjusted =P actual +K P ΔP

[0227] Among them, K P It is the proportional coefficient of path correction, which is used to control the correction amplitude.

[0228] 6.2.4 Path Smoothing

[0229] To avoid oscillation or sharp corners in the correction path, the system smoothes the path using Bezier curves to ensure smooth movement of the laser head.

[0230] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. A method for processing the depth problem of laser marking equipment, the specific steps are as follows, characterized in that: Step 1: Ensure uniform energy distribution of the laser beam through flat-top beam converter beam shaping technology; use aspheric lens optical elements to reduce energy attenuation at the edge of the spot; build a temperature-controllable optical platform to reduce the impact of temperature fluctuations on optical elements and laser beams; Step 2: Monitor the reflector angle and laser trajectory through a high-precision camera, and adjust the reflector position in real time in combination with a calibration algorithm; Step 3: Install a temperature and humidity sensor in the equipment’s built-in environmental sensing module to dynamically adjust the laser output parameters according to environmental changes to ensure production stability; Step 4: Use algorithms to analyze the error trend in the production process, dynamically optimize the marking path and power distribution, and adapt to different materials and process requirements; Step 5: When dealing with the problem of inconsistent marking depth, ensure the consistency of marking depth by dynamically adjusting the laser power and focus position; Step 6: The direction of the laser beam is monitored in real time through a high-precision camera and reflector angle monitoring system; when the laser beam direction is detected to be offset, the system automatically adjusts the angle of the reflector to ensure that the laser beam direction is consistent with the processing path.

2. A method for processing the problem of marking depth of a laser marking device according to claim 1, characterized in that: Step 1 can be described as: The flat-top beam converter converts the original Gaussian laser beam into a flat-top beam with uniform energy distribution. Multiple aspheric lenses are arranged to form a synthetic beam shaping device. Each lens deforms the beam to a certain extent by refraction, focal length change, etc., and finally combines into a uniform flat-top beam. The component material of the beam shaper is quartz glass, especially in the UV and IR bands. The flat-top beam converter is installed at the output end of the laser, at the starting position of the entire optical path. During the installation process, ensure that the optical axis of the beam shaper is aligned with the optical axis of the laser light source. At the same time, polarizers and gratings are used to control the directionality and stability of the beam. The grating selects the wavelength and disperses the beam. The temperature control system of the optical platform precisely controls the platform temperature. The temperature control system uses a method that combines a thermoelectric cooling module with a heating wire; the thermoelectric cooling module quickly adjusts the temperature based on sensor feedback; the temperature control system uses thermally conductive materials; the temperature control device is integrated at the bottom of the optical platform and fits closely with the platform structure; the temperature control system and the sensor are combined to form a closed-loop feedback mechanism.

3. The method for processing the depth problem of laser marking equipment according to claim 1 is characterized by: The real-time adjustment of the reflector position in step 2 can be expressed as: Step 2.1: Image acquisition and camera model The image data of the reflector and laser beam is captured in real time by a high-precision camera. The camera projects the object in the three-dimensional world coordinate system onto the two-dimensional image plane. Let the coordinates of the object in the three-dimensional world be (X, Y, Z), and the corresponding image coordinates be (x, y), which can be calculated using the following projection equation: Among them, K is the intrinsic parameter matrix of the camera, which represents the focal length and principal point coordinates; the specific form is: Among them, f x and f y is the focal length of the camera in the x and y directions, c x and c y is the coordinate of the optical center of the camera, and the coordinates of the reflector and laser beam in the three-dimensional space are projected onto the two-dimensional image plane through the projection model; Step 2.2 Image processing and feature extraction After the image data is collected, the Canny edge detection algorithm is used to extract the important feature edges in the image. The formula is as follows: Among them, G x and G y are the gradients of the image in the x and y directions, respectively, and I represents the image intensity. By calculating the gradient of the image, the edge position of the laser beam in the image is determined, and then the center of the laser beam in the image is extracted through algorithms such as SIFT and Harris corner detection. Step 2.3 Coordinate transformation and error calculation The key feature mirror position or laser beam center in the image needs to be matched with the actual position in the world coordinate system; therefore, the image coordinates need to be converted back to the actual physical coordinates and the deviation needs to be calculated; Let the coordinates of a point in the image be (x measured ,y measured ), the world coordinates (X world ,Y world ,Z world ); In order to perform accurate calibration, the calibration board is used to calibrate the camera's external parameters: rotation matrix and translation vector, and the image coordinates are converted to world coordinates using the following formula: Among them, R is the rotation matrix of the camera, and T is the translation vector; After obtaining the world coordinates, calculate the deviation between the image coordinates and the real coordinates; let the ideal coordinates of the target reflector position be (X ideal ,Y ideal ,Z ideal ), the actual measured coordinates are (X measured ,Y measured ,Z measured ), the position error ΔE is: This error represents the positioning error of the reflector, and the goal is to make this error as close to zero as possible; Adjust the mirror position in step 2.4 Through the above steps, the error of the reflector or laser beam position can be obtained; the error value is input into the feedback system in real time to adjust the reflector, and the output u(t) of the PID controller is used to adjust the position of the reflector. The formula is as follows: Among them, E target is the target error, E current is the current error, u(t) is the control signal, K p , K i , K d They are proportional, integral and differential gains of PID control respectively; by controlling the position of the reflector through the PID control system, the deviation of the reflector will be corrected.

4. A method for processing the depth problem of laser marking equipment according to claim 1, characterized in that: The process of dynamically adjusting the laser output parameters in step 4 can be expressed as follows: Step 3.1 Environmental monitoring and modeling An environmental sensing module is integrated inside the device, including a temperature and humidity sensor, to obtain environmental parameters in real time. The temperature and humidity sensor reading is set as T measured , H measured ,Combined with sensor data, a model of the impact of environmental changes on laser processing is established, including: ,the impact of temperature and humidity changes on the transmission efficiency of laser power P; Through experimental data and least squares fitting, the function of laser power loss ΔP and frequency loss Δf is defined as: ΔP=f(T,H) Where T is the ambient temperature, H is the relative humidity, and f() is the fitting function of the least squares and experimental data; Step 3.2 Dynamically adjust laser output parameters In order to compensate for the influence of environmental changes on the laser output power, the laser power P and frequency f are adjusted in real time; let the ideal laser power and frequency be P ideal and f ideal , the laser power P after dynamic adjustment adjusted and frequency f adjusted The output parameters are: P adjusted =P ideal +ΔP f adjusted =f ideal +Δf By adjusting P adjusted and f adjusted , ensuring the stability and consistency of laser beam energy and reducing the impact of environmental fluctuations.

5. The method for processing the depth problem of laser marking equipment according to claim 1 is characterized by: The process of dynamically optimizing the marking path and power distribution in step 4 can be expressed as follows: Step 4.1: Path error modeling and real-time feedback Step 4.1.1 Path Error Definition The path error measures the deviation between the ideal path and the actual processing path. The formula is as follows: e path (t)=r ideal (t)-r actual (t) Among them, t is the time variable, e path (t) is the path error vector; r ideal (t) is the ideal path, which is determined in advance by CAD design or planning algorithm, r ideal (t) The vector is represented as follows: r ideal (t)=[x ideal (t),y ideal (t),z ideal (t)] T Among them, x ideal (t), y ideal (t), z ideal (t) are the coordinates of the ideal path on the x, y, and z axes respectively; r actual (t) is the actual path, obtained by the measurement system, r actual (t) The vector is represented as follows: r actual (t)=[x actual (t),y actual (t),z actual (t)] T Step 4.1.2 Acquisition of measurement variables The processing path coordinates are acquired in real time through a high-precision laser rangefinder, an inertial measurement unit, and a machine vision system: the laser rangefinder is used to measure the distance between the laser focus and the processing plane to obtain z actual (t); The visual system collects the image of the processed surface through the camera and calculates x actual (t) and y actual (t); Step 4.2: Real-time path correction Step 4.2.1 The goal of the revision is to optimize the path r corrected (t), so that it is as close as possible to the ideal path r ideal (t); The optimization objective function is: Where, T is the integration time; Step 4.2.2 Path correction calculation, correction formula: r corrected (t)=r actual (t)+k path ·e path (t) Among them, r corrected (t) is the corrected path coordinate; k path is the path correction gain coefficient, which is used to adjust the correction amplitude; e path (t) is the path error, calculated by step 4.1; Step 4.2.3 Path smoothing To avoid oscillations or sharp corners in the correction path, smooth it using a Bezier curve: Among them, r smooth (t) is the smoothed path, r i To correct the path r corrected (t) is the control point on the curve, i is the order variable, and n is the order of the Bezier curve. is the Bezier curve basis function: Step 4.3: Comprehensive optimization path execution, the optimization path r smooth (t) is input to the controller and transmitted to the motion controller to control the movement of the laser head; the controller calculates the driving signal of the motor according to the corrected path so that the laser head follows the corrected path.

6. The method for processing the depth problem of laser marking equipment according to claim 1 is characterized by: The process of dealing with the problem of inconsistent marking depth in step 5 can be expressed as follows: Step 5.1 Dynamic adjustment of laser power Step 5.1.1 Laser power monitoring and feedback To ensure the consistency of marking depth, the system monitors the laser power output in real time and makes dynamic adjustments based on material characteristics and processing requirements. The laser power sensor monitors the laser output power in real time to ensure that the power value fluctuates within the set range. When it is detected that the laser power fluctuation exceeds the allowable range, the system automatically adjusts the laser output power to ensure power stability. Step 5.1.2 Power Adjustment Algorithm In order to dynamically adjust the laser power, let the ideal laser power be P ideal , the actual measured laser power is P actual , then the power error ΔP is: ΔP=P ideal -P actual According to the power error, the system adjusts the laser power P by the following formula adjusted : P adjusted =P actual +K p ·ΔP Among them, K p It is the proportional coefficient of power adjustment, used to control the adjustment range; Step 5.1.3 Material property adaptation. Different materials have different absorption rates for lasers. The system will automatically adjust the laser power according to the characteristics of the material. For materials with high absorption rates, the system will appropriately reduce the laser power to avoid marking too deep. For materials with low absorption rates, the system will increase the laser power to ensure sufficient marking depth. Step 5.2 Focus position calibration Step 5.2.1 Focus position monitoring: the system uses a high-precision laser rangefinder to monitor the distance between the laser focus and the processing plane in real time. The laser rangefinder is installed on the laser head and measures the distance d between the laser focus and the processing plane in real time. Let the ideal focus position be d ideal , the actual measured focal position is d actual , then the focus error Δd is: Δd=d ideal -d actual Step 5.2.2 Focus position adjustment: When the focus position is detected to be offset, the system will automatically adjust the position of the laser head to ensure that the focus position remains at the optimal position; according to the focus error, the system adjusts the position of the laser head by the following formula d adjusted : d adjusted =d actual +K d ·Δd Among them, K d The proportional coefficient for adjusting the focus position, used to control the adjustment amplitude.

7. The method for processing the depth problem of laser marking equipment according to claim 1 is characterized by: The process of the laser beam direction deviation problem in step 6 can be expressed as follows: Step 6.1 Laser beam direction calibration Step 6.1.1 Laser beam direction monitoring The direction of the laser beam is monitored in real time through a high-precision camera and reflector angle monitoring system. When the laser beam direction is detected to be offset, the system automatically adjusts the angle of the reflector to ensure that the laser beam direction is consistent with the processing path. The high-precision camera captures the image of the laser beam in real time, and the center position of the laser beam is extracted through the image processing algorithm; the angle of the reflector is monitored in real time through the angle sensor to ensure that the angle of the reflector is within the set range; Step 6.1.2 Direction error calculation Let the direction of the ideal laser beam be θ ideal , the actual measured laser beam direction is θ actual , then the direction error Δθ is: Δθ=θ ideal -θ actual Step 6.1.3 Reflector Angle Adjustment When the laser beam direction is detected to be offset, the system automatically adjusts the angle of the reflector to ensure that the laser beam direction is consistent with the processing path; according to the direction error, the system adjusts the angle θ of the reflector by the following formula adjusted : i adjusted =θ actual +K θ ·Dth Among them, K θ It is the proportional coefficient of the reflector angle adjustment, used to control the adjustment range; Step 6.2 Path correction and feedback Step 6.2.1 Path error monitoring The processing path coordinates are acquired in real time through high-precision laser rangefinder, inertial measurement unit and vision system to ensure the accuracy of the processing path; the laser rangefinder is used to measure the distance between the laser focus and the processing plane; the vision system collects the processing surface image through the camera and calculates the coordinates of the processing path; Step 6.2.2 Path error calculation Let the ideal path be P ideal , the actual measured path is P actual , then the path error ΔP is: ΔP=P ideal -P actual Step 6.2.3 Path Correction Algorithm When path deviation is detected, the system automatically corrects the path to ensure that the marking is not skewed; according to the path error, the system corrects the path P by the following formula adjusted : P adjusted =P actual +K P ·ΔP Among them, K P is the proportional coefficient of path correction, which is used to control the correction amplitude; 6.2.4 Path Smoothing The system uses Bezier curves to smooth the path to ensure smooth movement of the laser head.

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