A laser engraving device flat plate engraving control method for a mobile phone shell

Abstract

The application relates to the technical field of laser engraving, in particular to a flat engraving control method of a laser engraving device for a mobile phone shell, and is used for solving the technical problem of low engraving precision of a curved surface shell in the prior art. The method comprises the following steps: determining a curved surface engraving area of the mobile phone shell; determining an inertia error index of an engraving point position in the curved surface engraving area and a focal length adjustment degree of the engraving point position; wherein the inertia error index is used for representing the actual position deviation degree of the engraving point position caused by the inertial force; the focal length adjustment degree is used for representing the ability of maintaining the laser beam focusing precision when the laser engraving device adapts to the curved surface elevation change; determining an engraving rate requirement degree of the engraving point position according to the inertia error index and the focal length adjustment degree of the engraving point position; the engraving rate requirement degree is used for representing the requirement degree of the laser engraving rate adjustment of the engraving point position; and adjusting the engraving rate of the laser engraving device through a PID controller according to the engraving rate requirement degree.

Description

Technical Field

[0001] This application relates to the field of laser engraving technology, specifically to a flatbed engraving control method for laser engraving equipment on mobile phone casings. Background Technology

[0002] Currently, computer-controlled laser beams can be used to engrave complex patterns on the surface of mobile phone casings to meet consumers' pursuit of unique appearances. During the laser engraving process, galvanometer-type laser engraving equipment controls the trajectory of the laser beam through a pre-generated engraving path, thereby completing the processing of the predetermined pattern on the casing surface. With the diversification of mobile phone exterior designs, 2.5D curved casings are gradually becoming the market mainstream. Their surfaces simultaneously include planar and curved areas. Existing laser engraving control methods typically employ a uniform speed engraving strategy. While this method maintains good processing results in simple planar engraving, it struggles to adapt to the dynamic process requirements brought about by changes in elevation and abrupt changes in path direction when faced with complex curved surface features and personalized engraving paths with frequent turns. This results in a trade-off between the laser beam's focusing accuracy and position control accuracy, leading to relatively low engraving precision for curved casings. Summary of the Invention

[0003] To address the technical problem of low engraving accuracy for curved shells in existing technologies, this application aims to provide a flatbed engraving control method for laser engraving equipment of mobile phone shells. The specific technical solution adopted is as follows:

[0004] Determine the curved engraving area of ​​the phone case;

[0005] The inertial error index and focal length adjustment superiority of the engraving points in the curved surface engraving area are determined. The inertial error index is used to characterize the degree of actual positional deviation of the engraving points caused by inertial forces. The focal length adjustment superiority is used to characterize the ability of the laser engraving equipment to maintain the focusing accuracy of the laser beam when adapting to changes in the elevation of the curved surface.

[0006] Based on the inertial error index and the optimality of focal length adjustment at the engraving point, the engraving rate requirement at the engraving point is determined; the engraving rate requirement is used to characterize the degree of need for laser engraving rate adjustment at the engraving point.

[0007] The engraving rate of the laser engraving equipment is adjusted using a PID controller based on the required engraving rate.

[0008] In one possible implementation, determining the curved surface engraving area of ​​the phone case includes: obtaining the engraving path of the phone case; determining the elevation information of each engraving point in the engraving path; the elevation information is used to characterize the height information of the phone case surface in three-dimensional space; and dividing the engraving path into a planar engraving area and a curved surface engraving area according to the difference in elevation information on the engraving path.

[0009] In one possible implementation, determining the inertial error index of the carving point in the curved surface carving area includes: determining the carving influence intensity of the carving point based on the turning characteristics of the carving point in the curved surface carving area, the distance information between the carving point and the start / stop point, and the elevation difference between the carving point and the planar carving area; the carving influence intensity is used to characterize the degree of combined influence of the carving point on the turning start / stop inertia and the elevation difference; and determining the inertial error index of the carving point based on the carving influence intensity and the real-time displacement deviation of the carving point.

[0010] In one possible implementation, the carving influence intensity of a carving point is determined based on the turning characteristics of the carving point in the curved carving area, the distance information between the carving point and the start / stop point, and the elevation difference between the carving point and the planar carving area. This includes: determining the turning steepness based on the difference between the tangent vector slope in the turning characteristics of the carving point and the tangent vector slope of the previous carving point; determining the rate urgency factor based on the distance between the carving point and the start point in the carving process, and the distance to the stop point; the rate urgency factor is used to characterize the degree of urgency of the carving point for carving speed; determining the turning start / stop influence degree based on the turning steepness and the rate urgency factor; the turning start / stop influence degree is used to characterize the degree of influence of the path turning and start / stop position of the carving point on carving stability; and determining the carving influence intensity based on the turning start / stop influence degree and the elevation difference between the carving point and the planar carving area.

[0011] In one possible implementation, the inertial error index of the engraving point is determined based on the intensity of the engraving influence and the displacement deviation of the real-time engraving point. This includes: determining the coordinate deviation between the actual coordinates and the ideal coordinates of the real-time engraving point, and determining the maximum coordinate deviation during the historical engraving process of the mobile phone casing; calculating a first ratio between the coordinate deviation and the maximum coordinate deviation; and using the product of the first ratio and the intensity of the engraving influence as the inertial error index.

[0012] In one possible implementation, determining the focal length adjustment superiority of the engraving points in the curved surface engraving area includes: determining the laser focusing accuracy based on the laser energy focusing effect of the engraving points; the laser focusing accuracy is used to characterize the actual focusing precision of the laser energy acting on the shell surface at the current engraving point; and determining the focal length adjustment superiority based on the elevation change between the engraving point and the previous engraving point, as well as the change in laser focusing accuracy, wherein the focal length adjustment superiority is positively correlated with both the elevation change and the change in laser focusing accuracy.

[0013] In one possible implementation, the laser focusing accuracy is determined based on the laser energy focusing effect of the engraving points, including: determining an engraving reference factor based on the actual engraving depth and standard engraving depth of the engraving points in the already engraved planar engraving area; selecting a preset proportion of high-quality planar engraving points from the engraving points in the planar engraving area based on the engraving reference factor, as a high-confidence engraving point set; and determining the laser focusing accuracy by comparing the laser temperature of the current engraving point with the average laser temperature of the high-confidence engraving point set.

[0014] In one possible implementation, the carving rate requirement of the carving point is determined based on the inertia error index and the focal length adjustment superiority of the carving point, including: calculating a second ratio of the focal length adjustment superiority to the inertia error index; and using the normalized value of the second ratio as the carving rate requirement.

[0015] In one possible implementation, the engraving rate of the laser engraving equipment is adjusted by a PID controller according to the engraving rate requirement. This includes: mapping the engraving rate requirement to an adjustment amount of the proportional gain coefficient in the PID controller, and adjusting the proportional gain coefficient according to the adjustment amount; generating a control signal based on the adjusted proportional gain coefficient to drive the laser engraving equipment to execute the corresponding engraving rate; and dynamically updating the parameters of the PID controller based on the real-time determined engraving rate requirement during the engraving process.

[0016] In one possible implementation, after adjusting the engraving rate of the laser engraving equipment using a PID controller according to the engraving rate requirement, the method further includes: cleaning the surface of the engraved mobile phone casing; polishing the engraved area to remove surface burrs; and coloring and filling the engraved area.

[0017] In one possible implementation, after determining the elevation information of each carving point in the carving path, the method further includes: performing data cleaning and preprocessing on the acquired carving path information and elevation information.

[0018] This application offers the following advantages: For the curved surface engraving area of ​​a mobile phone casing, this application achieves refined control of the engraving process through two key parameters: inertial error index and focal length adjustment superiority. The inertial error index directly reflects the actual positional deviation of the laser head on the curved surface path caused by acceleration, deceleration, and turning. This parameter, by quantifying the impact of motion inertia on positioning accuracy, provides a crucial basis for the control system to suppress trajectory deviation. The focal length adjustment superiority characterizes the dynamic performance of the laser focusing system in adapting to changes in the surface elevation. This parameter, by evaluating the degree of matching between the focal point position and the casing surface, ensures that laser energy can be precisely focused at each point on the curved surface. These two parameters determine the engraving rate requirement during the curved surface engraving process from the two dimensions of motion trajectory control and energy focusing control, respectively. This allows the PID controller to make precise adjustments based on the engraving rate requirement, thereby improving the engraving accuracy of the curved surface engraving area. Attached Figure Description

[0019] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A flowchart illustrating a flatbed engraving control method for a laser engraving device for a mobile phone casing, provided as an embodiment of this application. Figure 1 ;

[0021] Figure 2 This is a schematic diagram illustrating laser engraving of a mobile phone casing as an embodiment of this application.

[0022] Figure 3 This is a schematic diagram illustrating the engraving principle of a laser engraving machine based on a galvanometer laser engraving machine, provided as an embodiment of this application.

[0023] Figure 4 A flowchart illustrating a flatbed engraving control method for a laser engraving device for a mobile phone casing, provided as an embodiment of this application. Figure 2 ;

[0024] Figure 5 A flowchart illustrating a flatbed engraving control method for a laser engraving device for a mobile phone casing, provided as an embodiment of this application. Figure 3 ;

[0025] Figure 6 A flowchart illustrating a flatbed engraving control method for a laser engraving device for a mobile phone casing, provided as an embodiment of this application. Figure 4 ;

[0026] Figure 7 A flowchart illustrating a flatbed engraving control method for a laser engraving device for a mobile phone casing, provided as an embodiment of this application. Figure 5 . Detailed Implementation

[0027] To further illustrate the technical means and effects adopted by this application to achieve the intended purpose of the invention, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a laser engraving control method for a mobile phone casing based on this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0029] The following description, in conjunction with the accompanying drawings, details a specific scheme for a flatbed engraving control method for a laser engraving device for a mobile phone casing provided in this application.

[0030] Please see Figure 1 The diagram illustrates a flowchart of a flatbed engraving control method for a laser engraving device on a mobile phone casing, according to an embodiment of this application. The method includes:

[0031] Step 101: Determine the curved engraving area of ​​the phone case.

[0032] In one possible implementation, the phone casing is a 2.5D curved casing, and the casing surface includes a planar engraving area and a curved engraving area. The planar engraving area is engraved based on the uniform speed engraving strategy in the prior art, while the curved engraving area needs to be engraved based on the flatbed engraving control method of the laser engraving equipment for the phone casing provided in this application, in order to improve the engraving accuracy of the curved engraving area.

[0033] Optionally, this application can determine the curved engraving area based on the height difference of the phone casing (which can also be understood as depth, or surface flatness, etc.). This is because the surface height of the planar engraving area in the phone casing is uniform, while the height of the curved engraving area usually varies and is significantly higher than that of the planar engraving area.

[0034] As an example, such as Figure 2 The diagram shown is a schematic diagram of laser engraving for engraving a mobile phone casing according to this application.

[0035] Optionally, the laser engraving in this application can be performed using a galvanometer-type laser engraving machine, whose main structure consists of a galvanometer group and a lens group. A laser beam, driven in a fixed direction, is reflected by X and Y axis galvanometers to move the beam on the XOY plane. The reflected laser is then focused and transmitted to the target engraving point by the lens group, achieving multi-axis coordination to improve engraving efficiency. For example... Figure 3 The diagram shown is a schematic diagram of the engraving principle of laser engraving based on a galvanometer laser engraving machine provided in this application.

[0036] Step 102: Determine the inertial error index of the carving points in the curved surface carving area and the optimality of the focal length adjustment of the carving points.

[0037] Among them, the inertia error index is used to characterize the degree of actual position deviation of the engraving point caused by inertial force; the focal length adjustment superiority is used to characterize the ability of the laser engraving equipment to maintain the focusing accuracy of the laser beam when adapting to changes in the elevation of the curved surface.

[0038] It should be noted that the patterns engraved on the phone casing may be customized, and there may be many turning and start / stop points along the engraving path. These points can affect the engraving accuracy. For example, for engraving points with steeper turning points, the laser beam may deviate from the actual engraving position due to inertia. In this case, the engraving speed needs to be reduced to mitigate the inertial effect. Furthermore, the phone casing uses a 2.5D curved surface design, and its curved engraving area has a certain elevation change in the Z-axis direction. The laser engraving machine needs to calculate the required focal length adjustment through a dynamic focal length control algorithm, and then adjust the lens position to achieve the target focal length. Therefore, this application can determine the inertial error index of the engraving points and the optimality of the focal length adjustment of the engraving points, and thus provide a basis for parameter adjustment of curved surface engraving based on these two indicators.

[0039] Step 103: Based on the inertia error index and the focal length of the engraving point, adjust the positioning to determine the engraving rate requirement of the engraving point.

[0040] Among them, the engraving rate requirement is used to characterize the degree to which the engraving point needs to adjust the laser engraving rate.

[0041] It is important to note that the engraving rate demand provides the PID controller with precise control direction and intensity, normalizing the complex multi-dimensional quality status (trajectory accuracy + focus quality) into a single rate adjustment command. This allows the PID controller to execute precise responses with a clear target orientation. Specifically, when the demand indicates a need to reduce speed, the system prioritizes ensuring engraving accuracy by reducing the rate to suppress errors. When the demand indicates that the speed can be maintained or appropriately increased, the system optimizes processing efficiency while ensuring quality. This control mechanism based on dual-parameter fusion decision-making ultimately achieves an adaptive balance between accuracy control and efficiency optimization in complex surface engraving.

[0042] As an example, the carving rate requirement is determined by the hyperbolic tangent function, with a value range of (-1, 1).

[0043] Step 104: Adjust the engraving rate of the laser engraving equipment using a PID controller according to the required engraving rate.

[0044] As one possible implementation, this step can be implemented as follows: mapping the engraving rate demand to an adjustment amount of the proportional gain coefficient in the PID controller, and adjusting the proportional gain coefficient according to the adjustment amount; generating a control signal based on the adjusted proportional gain coefficient to drive the laser engraving equipment to execute the corresponding engraving rate; and dynamically updating the parameters of the PID controller based on the real-time determined engraving rate demand during the engraving process.

[0045] Specifically, initial PID control parameters, including the proportional gain coefficient Kp, are obtained. The engraving rate requirement γ is incremented by 1 and multiplied by the initial proportional gain coefficient to obtain the adjusted proportional gain value. This adjusted parameter is then configured to the PID controller. The output of the PID controller is converted into a control signal to drive the laser engraving equipment to perform the corresponding engraving rate adjustment. During continuous engraving, the parameters of the PID controller are dynamically updated based on real-time acquired processing status data to maintain control stability during the engraving process. At the end of the control cycle, the system response characteristics are evaluated to determine if overshoot exists. Based on the actual control effect, relevant parameters are fine-tuned and optimized to improve the efficiency of subsequent engraving processes and system performance.

[0046] Optionally, after adjusting the engraving speed of the laser engraving equipment, the surface of the engraved phone casing is cleaned; the engraved area is polished to remove surface burrs; and the engraved area is colored and filled to complete the engraving of the phone casing. Specifically, the engraving speed parameter is controlled in real time by a PID controller, enabling the laser engraving equipment to respond quickly to real-time engraving needs. After processing all engraving path points, the laser output is turned off, and the surface of the phone casing is cleaned of dust and debris using water-free and oil-free compressed air or a special air gun. High-grit sandpaper (1000 grit or higher), polishing paste, or fiber polishing pads are used to finely polish the engraved area to remove burrs and flash generated during processing. Special inks (including epoxy resin inks, UV inks, etc.) are applied to the engraved area through precise spraying or scraping. After coloring, the area is left to cure or baked at a low temperature to fully harden, realizing the complete laser engraving control process.

[0047] Based on the above technical solution, this application achieves refined control of the engraving process for the curved surface engraving area of ​​the mobile phone casing through two key parameters: inertial error index and focal length adjustment superiority. The inertial error index directly reflects the actual positional deviation of the laser head on the curved surface path caused by acceleration, deceleration, and turning. This parameter, by quantifying the impact of motion inertia on positioning accuracy, provides a crucial basis for the control system to suppress trajectory deviation. The focal length adjustment superiority characterizes the dynamic performance of the laser focusing system in adapting to changes in the surface elevation. This parameter, by evaluating the degree of matching between the focal point position and the casing surface, ensures that laser energy can be precisely focused at each point on the curved surface. These two parameters determine the engraving rate requirement during the curved surface engraving process from the two dimensions of motion trajectory control and energy focusing control, respectively. This allows the PID controller to make precise adjustments based on the engraving rate requirement, thereby improving the engraving accuracy of the curved surface engraving area.

[0048] like Figure 4 As shown, in one possible implementation, the process of determining the curved engraving area of ​​the phone casing in step 101 can be specifically achieved through the following steps:

[0049] Step 401: Obtain the engraving path of the phone case.

[0050] As one possible implementation, this application imports the target pattern to be engraved on the mobile phone casing into image analysis software, which then generates the corresponding engraving path. Optionally, the image analysis software includes Wentai engraving software and JDPaint.

[0051] In the laser engraving software, the initial settings of process parameters, including laser power, scanning speed, number of engravings and frequency, are completed, and the reference positioning and focusing operation is performed; the coordinate information of the start point and stop point in the engraving path is parsed and obtained from the generated engraving path.

[0052] Step 402: Determine the elevation information of each carving point in the carving path.

[0053] Among them, elevation information is used to characterize the height of the phone casing surface in three-dimensional space.

[0054] As one implementation method, this application uses a laser displacement sensor to collect elevation information at various locations on the surface of the mobile phone casing. Specifically, the laser displacement sensor acquires the actual elevation data of each engraved point after benchmark positioning and focusing, and simultaneously collects the actual engraving depth information of the engraved points; this information is then aggregated into elevation information.

[0055] Step 403: Based on the differences in elevation information along the carving path, divide the carving path into a planar carving area and a curved carving area.

[0056] In one possible implementation, this application can calculate parameters such as the range, standard deviation, and curvature value of elevation information, and use the variance and standard deviation as the differences in elevation information. Based on these differences, the carving path is divided into planar carving areas and curved carving areas.

[0057] Taking the range as an example, this application divides the carving path into several square grids with a side length of L, and calculates the elevation range (the difference between the maximum elevation value and the minimum elevation value) of all points in each grid. When the range is less than or equal to 0.1 mm, the grid is determined to be a planar carving area; when the range is greater than 0.1 mm, it is marked as a curved carving area.

[0058] Taking standard deviation as an example, this application establishes a circular analysis window with radius R, centered on each point on the carving path, and calculates the standard deviation of the elevation data of all points within the window. When the standard deviation is less than or equal to 0.05 mm, the area is determined to be a planar carving area; when the standard deviation is greater than 0.05 mm, it is classified as a curved carving area.

[0059] Taking curvature value as an example, the curvature value of each point in the X and Y directions is calculated using elevation data collected by a laser displacement sensor. When the absolute value of the maximum curvature is less than or equal to... When the absolute value of curvature is greater than a certain value, the area is determined to be a planar carving area; when the absolute value of curvature is greater than a certain value, the area is determined to be a planar carving area. When that happens, it is divided into curved surface carving areas.

[0060] Optionally, after determining the planar carving area and the curved carving area, the planar carving area is carved at a uniform speed using preset empirical parameters, while the curved carving area's parameters are adjusted during the carving process based on the method provided in this application. Furthermore, this application can also collect temperature data of each carving point in real time at the instant of laser beam action using a thermal imaging module, where the coordinates of the highest temperature point in the temperature distribution are the actual laser action location; the collected elevation information, carving depth information, and temperature data are cleaned and preprocessed; the preprocessed data is uploaded to the data acquisition system to provide data support for subsequent analysis and processing. For example, the data cleaning and preprocessing process includes, but is not limited to: outlier removal, noise filtering, data alignment, missing value handling, and normalization processing; this application does not limit these processes.

[0061] Based on the above technical solution, this application establishes a complete digital model of the processed object by acquiring the carving path and elevation information. The elevation information accurately describes the three-dimensional morphological features of the shell surface. The region division method based on elevation differences can effectively distinguish the different process requirements of planes and curved surfaces, providing accurate spatial structure data support for the implementation of subsequent differentiated control strategies.

[0062] like Figure 5As shown, as one possible implementation, the process of determining the inertial error index of the carving points in the curved surface carving area in step 102 above can be specifically implemented through the following steps:

[0063] Step 501: Determine the carving influence intensity of the carving point based on the turning characteristics of the carving point in the curved surface carving area, the distance information between the carving point and the start / stop point, and the elevation difference between the carving point and the planar carving area.

[0064] Among them, the carving influence intensity is used to characterize the combined influence of the carving point on the inertia of turning and starting and stopping, as well as the elevation difference.

[0065] As one possible implementation, this step can be achieved through the following process: Determine the turning steepness based on the difference between the tangent vector slope of the turning feature of the carving point and the tangent vector slope of the previous carving point; determine the rate urgency factor based on the distance between the carving point and the starting point in the carving process, and the distance to the stopping point; the rate urgency factor characterizes the degree of urgency of the carving point for carving speed; determine the turning start-stop influence degree based on the turning steepness and the rate urgency factor; the turning start-stop influence degree characterizes the degree of influence of the path turning and start-stop positions of the carving point on carving stability; determine the carving influence intensity based on the turning start-stop influence degree and the difference between the elevation of the carving point and the elevation of the planar carving area.

[0066] Specifically, during laser engraving, due to the weak laser energy and insufficient thermal accumulation effect in the start-up phase, a slower engraving rate is required at the start point and its adjacent area to ensure sufficient material melting. Conversely, in the stop phase, due to the strong accumulated laser energy, a faster engraving rate is needed to prevent over-melting of the material. Based on this principle, this step integrates the turning characteristics of the path with the start and stop positions to quantify the engraving influence intensity of each engraving point.

[0067] For regions with curvature changes in the carving path, the high-speed laser beam may cause positional deviations at actual points due to inertia. Therefore, it is necessary to evaluate the steepness of the path's turning point. Based on the carving path obtained in the previous step, a specific carving point in the curved carving area is selected as the analysis object, and the slope of the tangent vector at that point in the real-time path is calculated. And obtain the slope of the tangent vector at the previous engraving point. The turning steepness of the current point is calculated in the following way.

[0068] As an example, steepness of the turn Satisfy the following formula:

[0069]

[0070] in, This represents the slope of the tangent vector at the current carving point in the real-time path. This represents the slope of the tangent vector of the previous carving point in the real-time path. Turning steepness reflects the degree of directional change of the current carving point relative to the previous point; a larger value indicates a steeper path turn. This is a data normalization function used to scale data to a specific range (e.g., [0,1]) according to rules, in order to eliminate differences in units and unify the data scale. For example,

[0071] Since the engraving path typically consists of multiple processing segments, with start and stop points between each segment, different segments have specific requirements for the engraving rate. To quantify this effect, we obtain the Euclidean distance D between the currently analyzed engraving point and the start point of its respective processing segment, as well as the Euclidean distance D from the stop point. Then, the rate urgency factor is calculated.

[0072] As an example, the rate urgency factor Satisfy the following formula:

[0073]

[0074] Where D is the Euclidean distance between the currently analyzed carving point and the starting point of the corresponding processing section. This is the Euclidean distance between the currently analyzed engraving point and the stop point of its corresponding processing segment. Based on this formula, the closer the current engraving point is to the starting point and the farther it is from the stop point in the current engraving process, the higher the engraving rate should be applied to the current engraving point. It should be noted that the above formula applies to the case where D is not zero, and where the currently analyzed engraving point is the starting point of its corresponding processing segment. The value is directly assigned to the maximum value of 1.

[0075] The current analysis focuses on the steepness of the turning point. The higher the rate urgency factor The smaller the value, the more the real-time carving rate needs to be reduced under the influence of steering start-stop. Therefore, this application can be based on the steering steepness. and rate urgency factor Calculate the impact of steering start-stop.

[0076] As an example, the impact of steering start-stop Satisfy the following formula:

[0077]

[0078] in, For parameter tuning coefficients, if If it is 0, then set it to 0.001. If the value is not 0, then set it to 0. Based on this formula, the influence of steering start-stop is... This comprehensively reflects the combined impact of path turning and start / stop positions on carving stability. A higher value indicates a need to reduce the carving speed to ensure processing quality. A larger turning and start / stop influence value G represents a steeper path turning (i.e.,... The larger the (i.e., the weaker the urgent need for high-speed engraving) The smaller the value of G, the higher the risk of positional deviation of the laser head due to inertia, requiring a reduction in the engraving speed to improve engraving stability; conversely, the smaller the value of G, the higher the engraving speed can be to balance efficiency.

[0079] Furthermore, due to the elevation differences between points in the curved surface carving area along the Z-axis, these differences amplify the errors introduced by steering and start / stop. Therefore, by obtaining the elevation value H of the current analysis point and the elevation reference value H' of the planar carving area, the carving influence intensity α is finally calculated using the following method:

[0080]

[0081] The carving influence intensity α comprehensively characterizes the combined effect of elevation difference and steering start-stop influence on carving quality. The larger the value, the higher the difficulty of carving control at that point, requiring more precise rate regulation. Optionally, this application uses the average elevation value of all points divided into planar carving areas as the elevation reference value H'.

[0082] Based on the above calculation process, this application calculates the carving influence intensity of all points within the curved surface carving area.

[0083] Step 502: Determine the inertial error index of the carving point based on the carving influence intensity and the real-time displacement deviation of the carving point.

[0084] As one possible implementation method, this step can be achieved through the following process: determining the coordinate deviation between the actual coordinates and the ideal coordinates of the real-time engraving point, and determining the maximum coordinate deviation during the historical engraving process of the mobile phone casing; calculating the first ratio between the coordinate deviation and the maximum coordinate deviation; and using the product of the first ratio and the engraving influence intensity as the inertia error index.

[0085] For mobile phone casings with a 2.5D curved surface design, the carved area exhibits elevation changes along the Z-axis. Laser engraving equipment needs to calculate the focal length adjustment using a dynamic focal length control algorithm and adjust the lens position to achieve the target focal length. Since the laser propagation speed is much higher than the mechanical adjustment speed of the lens, using a higher engraving speed at points with significant focal length adjustment requirements will lead to insufficient focal length adjustment, thus introducing processing errors. Therefore, this step uses real-time displacement deviation data to perform a fusion analysis of the engraving impact intensity, obtaining an inertial error index, and then combining this with the focal length adjustment requirements to determine the required engraving speed for each point.

[0086] Specifically, the carving influence intensity is based on the results obtained from the preceding steps. A detailed analysis is performed by combining real-time deviation data from the carving process. The actual coordinates of real-time points are obtained through a thermal imaging sensor module. The ICP algorithm is then used to register these actual coordinates with the ideal coordinates in the carving software, yielding the Euclidean distance between the actual and ideal coordinates. (That is, the coordinate deviation between the actual coordinates and the ideal coordinates of the real-time carving point mentioned above), and at the same time, obtain the maximum value of the coordinate deviation of the point during the historical carving process. (That is, the maximum coordinate deviation during the historical engraving process of the machine casing mentioned above), based on the intensity of the engraving influence. Euclidean distance between actual coordinates and ideal coordinates And the maximum value of the coordinate deviation of the points during the historical carving process. (In the actual carving process, the coordinates of the carving points cannot be completely consistent with the ideal coordinates, therefore, in this application...) (The value of is always greater than 0), calculate the inertial error index. .

[0087] As an example, inertial error index Satisfy the following formula:

[0088]

[0089] in, This is the first ratio mentioned earlier, the inertia error index. It reflects the overall error level caused by the inertial force of steering and starting / stopping. The larger the value, the greater the actual position deviation of the current point.

[0090] Based on the above technical solution, this application obtains the turning steepness by calculating the difference in the slope of the tangent vector at the carving points, effectively quantifying the severity of path direction changes and providing geometric feature basis for identifying high-risk areas of inertial error. It determines the rate urgency factor by analyzing the distance relationship between the carving points and the start / stop points, accurately reflecting the special requirements of thermal accumulation effects on processing quality during the start / stop phase. The turning steepness and rate urgency factor are integrated into a turning start / stop influence degree, which, combined with elevation differences, forms a comprehensive evaluation index that fully reflects path complexity, motion characteristics, and surface morphology. This multi-level parameter fusion method enables the system to identify key risk points in the carving path in advance, providing precise feedforward control signals for subsequent inertial error compensation and focus adjustment, thereby significantly improving the system's adaptability and control accuracy to complex curved paths.

[0091] like Figure 6 As shown, as one possible implementation, the process of determining the focal length adjustment priority of the carving points in the curved surface carving area in step 102 above can be implemented through the following steps:

[0092] Step 601: Determine the laser focusing accuracy based on the laser energy focusing effect at the engraving point.

[0093] Among them, laser focusing accuracy is used to characterize the actual focusing accuracy of the laser energy acting on the surface of the shell at the current engraving point.

[0094] As one possible implementation, this step can be specifically implemented as follows: determining a carving reference factor based on the actual carving depth and standard carving depth of the carving points in the already carved planar carving area; selecting a preset proportion of high-quality planar carving points from the carving points in the planar carving area based on the carving reference factor, as a high-confidence carving point set; and determining the laser focusing accuracy by comparing the laser temperature of the current carving point with the average laser temperature of the high-confidence carving point set.

[0095] Specifically, during laser engraving, to adapt to changes in surface elevation, the equipment needs to continuously adjust the focal length to ensure the beam focus remains on the shell surface. Considering that the shell flatness in the planar engraving area is better than in the curved area, the current curved surface point can be compared and analyzed with the points in the completed planar points where the focusing effect is better.

[0096] As an example, for a single completed planar engraving point, its actual engraving depth Z and standard engraving depth Z' are obtained, and the engraving reference factor U for that point is calculated as follows:

[0097]

[0098] It should be noted that when carving points, the standard carving depth Z' must be greater than 0 in order to form the carved pattern; the formula in this case... For parameter tuning coefficients, if If it is 0, then set it to 0.001. If the value is not 0, it is set to 0. Based on this formula, the engraving reference factor U reflects the engraving quality of the planar point, and the larger the value, the higher the reference value of the point. Optionally, this application selects some points with uniform actual engraving depth and the best visual effect from the already engraved planar engraving area, calculates the average actual engraving depth of these points, and uses this average value as the standard engraving depth Z'.

[0099] As an example, the aforementioned preset ratio is set to 20%. In other words, this application selects the top 20% of the engraving reference factors U from all completed planar points to form a high-confidence engraving point set.

[0100] As an example, based on the principle that the instantaneous temperature of the laser beam reflects the accuracy of energy focusing, the real-time temperature W of the current analysis point and the average temperature of the high-confidence point set are obtained. The laser focusing accuracy A is calculated as follows:

[0101]

[0102] The larger the value of the laser focusing accuracy parameter A, the higher the focusing accuracy at the current point. exp represents an exponential function with the natural constant e as the base.

[0103] Step 602: Determine the optimal focus adjustment based on the elevation change between the engraving point and the previous engraving point, as well as the change in laser focusing accuracy.

[0104] Among them, the focus adjustment superiority is positively correlated with the change in elevation and the change in laser focusing accuracy.

[0105] Specifically, during the carving process, different carving points exhibit varying depth variations, leading to different focal length adjustment requirements. If the vertical change in the z-axis direction of a real-time point is steeper than that of the previous point, the focal length adjustment requirement is relatively greater. Furthermore, if the laser focusing accuracy of a real-time point is significantly higher than that of the previous point, it further indicates superior focal length adjustment at that real-time point. Therefore, this application uses the depth difference in elevation between the current point and the previous point as a focal length control resistance parameter, calculating the difference between the focal length control resistance parameters corresponding to the current carving point and the previous point. Simultaneously calculate the laser focusing accuracy between the current point and the previous point. The difference Based on the difference Sum and Difference Calculate the optimality of focal length adjustment.

[0106] As an example, focus adjustment priority Satisfy the following formula:

[0107]

[0108] Focal length adjustment priority It reflects the overall effect of focal length adjustment from the previous position to the current position. The larger the value, the better the focal length adjustment performance.

[0109] Based on the above technical solution, this application evaluates the focal length adjustment performance by jointly analyzing the changes in elevation and focus accuracy. The changes in elevation reflect the difficulty required for focal length adjustment, while the changes in focus accuracy reflect the actual adjustment effect. Together, they determine the value of the focal length adjustment priority. This evaluation method can accurately distinguish between the effects of active adjustment and passive adaptation, providing reliable focal length status information for rate decision-making.

[0110] like Figure 7 As shown, as one possible implementation, the process of determining the carving rate requirement of the carving point by adjusting the dominance based on the inertia error index and the focal length of the carving point in step 103 above can be specifically implemented through the following steps:

[0111] Step 701: Calculate the second ratio of focal length adjustment superiority to inertia error index.

[0112] Step 702: Use the normalized value of the second ratio as the engraving rate requirement.

[0113] Specifically, if the inertia error index of the current carving point The smaller the value, the smaller the error introduced by the steering start-stop mechanism at that point, and the better the focus adjustment. The better the quality, the better the focus adjustment at the current engraving point. In this case, the real-time engraving speed can be appropriately increased.

[0114] As an example, the carving rate requirement Satisfy the following formula:

[0115]

[0116] in, This is the second ratio mentioned above. This represents the hyperbolic tangent function. It should be noted that this calculation process is based on real-time data from the already engraved points, and is applied to subsequent engraving processes via a PID controller; its timing lag is negligible. In this formula... For parameter tuning coefficients, if If it is 0, then set it to 0.001. If it is not 0, then set it to 0. Here, constant 1 is the equilibrium threshold: when... When γ is greater than 1, it indicates that the focus adjustment performance is better than the inertia error; γ is positive, and speed needs to be increased. When the value is less than 1, it indicates that the focus adjustment performance is worse than the inertial error. When γ is negative, the speed needs to be reduced.

[0117] This application can calculate the required carving rate for each surface carving point based on the above calculation process. Therefore, based on the carving speed requirement Adjust the carving parameters.

[0118] Based on the above technical solution, this application uses the ratio of focal length adjustment quality to inertia error index as the engraving speed requirement, which reflects the system's trade-off mechanism between focusing accuracy and positional accuracy. When the focal length adjustment is good, appropriate speed increase is allowed, and when the inertia error is large, speed reduction compensation is required, thereby achieving a balance between processing quality and efficiency.

[0119] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0120] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A laser engraving apparatus flat panel engraving control method of a mobile phone case, characterized by, The method comprises: determining a curved engraving area of a mobile phone shell; determining an inertia error index of an engraving point in the curved engraving area and a focal length adjustment degree of the engraving point; wherein the inertia error index is used to represent the actual position deviation degree of the engraving point caused by the inertial force; the focal length adjustment degree is used to represent the ability of maintaining the focusing accuracy of the laser beam when the laser engraving equipment adapts to the elevation change of the curved surface; determining the engraving rate requirement degree of the engraving point according to the inertia error index and the focal length adjustment degree of the engraving point; the engraving rate requirement degree is used to represent the requirement degree of the engraving point for the laser engraving rate adjustment; adjusting the engraving rate of the laser engraving equipment through the PID controller according to the engraving rate requirement degree.

2. The laser-engraving apparatus flatbed engraving control method for a cellphone case according to claim 1, wherein, Determining the curved engraving area of the mobile phone shell comprises: obtaining an engraving path of the mobile phone shell; determining the elevation information of each engraving point in the engraving path; the elevation information is used to represent the height information of the mobile phone shell surface in the three-dimensional space; dividing the engraving path into a planar engraving area and a curved engraving area according to the difference of the elevation information on the engraving path.

3. The method of claim 1, wherein the method further comprises: Determining the inertia error index of the engraving point in the curved engraving area comprises: determining the engraving influence intensity of the engraving point according to the turning feature of the engraving point in the curved engraving area, the distance information between the engraving point and the start and stop points, and the elevation difference between the engraving point and the planar engraving area; the engraving influence intensity is used to represent the comprehensive influence degree of the turning start and stop inertia and the elevation difference on the engraving point; determining the inertia error index of the engraving point according to the engraving influence intensity and the displacement deviation of the real-time engraving point.

4. The laser-engraving apparatus flatbed engraving control method for a cellphone case according to claim 3, wherein, Determining the engraving influence intensity of the engraving point according to the turning feature of the engraving point in the curved engraving area, the distance information between the engraving point and the start and stop points, and the elevation difference between the engraving point and the planar engraving area comprises: determining the turning steepness degree according to the difference between the tangent vector slope in the turning feature of the engraving point and the tangent vector slope of the previous engraving point; determining the rate urgency factor according to the distance between the engraving point and the start point in the engraving process, and the distance between the engraving point and the stop point; the rate urgency factor is used to represent the urgent requirement degree of the engraving point for the engraving rate; determining the turning start and stop influence degree according to the turning steepness degree and the rate urgency factor; the turning start and stop influence degree is used to represent the influence degree of the path turning and start and stop positions of the engraving point on the engraving stability; determining the engraving influence intensity according to the turning start and stop influence degree and the elevation difference between the engraving point and the planar engraving area.

5. The method of claim 3, wherein the method further comprises: Determining the inertia error index of the engraving point according to the engraving influence intensity and the displacement deviation of the real-time engraving point comprises: determining the coordinate deviation between the actual coordinates and the ideal coordinates of the real-time engraving point, and determining the maximum value of the coordinate deviation in the historical engraving process of the mobile phone shell; calculating the first ratio of the coordinate deviation and the maximum value of the coordinate deviation; The product of the first ratio and the engraving influence strength is taken as the inertia error index.

6. The method of claim 1, wherein the method further comprises: The focus adjustment optimization degree of the engraving point position in the curved surface engraving area is determined, including: According to the laser energy focusing effect of the engraving point position in the curved surface engraving area, the laser focusing accuracy is determined; the laser focusing accuracy is used to represent the actual focusing precision of the laser energy acting on the shell surface at the current engraving point position; According to the change in elevation and the change in laser focusing accuracy of the engraving point position and the previous engraving point position, the focus adjustment optimization degree is determined, which is positively correlated with the change in elevation and the change in laser focusing accuracy.

7. The method of claim 6, wherein the method further comprises: According to the laser energy focusing effect of the engraving point position, the laser focusing accuracy is determined, including: Based on the actual engraving depth and the standard engraving depth of the engraved point position in the completed planar engraving area, the engraving reference factor is determined; Based on the engraving reference factor, a preset proportion of high-quality planar engraving point positions in the engraved point positions in the planar engraving area are selected as a high-confidence engraving point set; By comparing the laser action temperature of the current engraving point position with the average laser action temperature of the high-confidence engraving point set, the laser focusing accuracy is determined.

8. The method of claim 1, wherein the method further comprises: According to the inertia error index and the focus adjustment optimization degree of the engraving point position, the engraving rate requirement degree of the engraving point position is determined, including: The second ratio of the focus adjustment optimization degree and the inertia error index is calculated; The normalized value of the second ratio is taken as the engraving rate requirement degree.

9. The method of claim 1, wherein the method further comprises: According to the engraving rate requirement degree, the engraving rate of the laser engraving equipment is adjusted by a PID controller, including: The engraving rate requirement degree is mapped to an adjustment amount of the proportional gain coefficient in the PID controller, and the proportional gain coefficient is adjusted according to the adjustment amount; According to the adjusted proportional gain coefficient, a control signal is generated to drive the laser engraving equipment to perform corresponding engraving rate; During the engraving process, the parameters of the PID controller are dynamically updated based on the real-time determined engraving rate requirement degree.

10. The method of claim 1, wherein the method further comprises: After adjusting the engraving rate of the laser engraving equipment by the PID controller according to the engraving rate requirement degree, the method further includes: Cleaning the surface of the completed engraved mobile phone shell; Grinding the engraving area to remove surface burrs; Coloring and filling the engraved area.

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