Sheet metal part laser coding focusing method and device

Abstract

This invention relates to the field of machining technology, specifically to a method and apparatus for focusing laser marking on sheet metal parts. The method includes: selecting and installing a displacement sensor: selecting a displacement sensor and determining its installation position on a laser marking machine; determining the movement relationship: acquiring multiple sets of parameters from the displacement sensor and the laser marking machine during movement, and determining the movement relationship; determining the accurate focusing position of the laser marking machine: based on the movement relationship, determining the position coordinates of the laser marking machine when accurately focused, and adjusting the position of the laser marking machine. This invention overcomes the shortcomings of existing technologies and ensures accurate laser marking focus.

Description

Technical Field

[0001] This invention relates to the field of machining technology, specifically to a laser marking and focusing method and apparatus for sheet metal parts. Background Technology

[0002] Post-laser cutting management of sheet metal parts is crucial. This primarily involves saving and transmitting information such as the material, dimensions, and production details of the sheet metal parts. Users can quickly access this information, improving production efficiency and reducing errors. Laser marking machines can print sheet metal information as QR codes onto the surface of large sheets before laser cutting, following a predetermined arrangement of the parts.

[0003] Because vertical laser marking machines require precise focusing, their height is fixed. However, due to the large area of ​​the material (6 meters long and 2 meters wide) and its thinness, deformation is likely. Additionally, the QR code is relatively small (10mm*10mm) and contains a large amount of information. The smaller the internal squares of the QR code, the higher the requirement for the clarity of its black and white pixels. This places higher demands on the focusing height of the laser marking machine (less than ±0.5mm). Therefore, if the overall warping deformation exceeds the tolerance, the laser marking machine will be unable to focus correctly, resulting in a blurry and unscannable QR code. Thus, before marking, the laser machine must be accurately moved to a suitable focusing height. Summary of the Invention

[0004] The purpose of this invention is to provide a laser marking focusing method and apparatus for sheet metal parts, which can overcome the shortcomings of the prior art and ensure accurate laser marking focusing.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect of the present invention, a laser marking focusing method for sheet metal parts is disclosed, the method comprising:

[0007] S1. Selection and Installation of Displacement Sensor: Select a displacement sensor and determine its installation position on the laser marking machine. Unlike conventional offset installation methods for displacement sensors, in this invention, the displacement sensor is installed at an angle, and this angle is adjustable.

[0008] S2. Determination of the movement relationship: Obtain parameters from multiple sets of displacement sensors and the laser marking machine during movement, and determine the movement relationship. Since the displacement sensors are installed at an angle, the intuitive data is a tilt distance and cannot be used directly. Therefore, it is necessary to find the linear relationship between the sensor data and the laser machine's height coordinates.

[0009] S3. Determining the accurate focusing position of the laser marking machine: Based on the aforementioned movement formula, determine the position coordinates of the laser marking machine when it is accurately focused, and adjust the position of the laser marking machine.

[0010] Furthermore, the selection and installation of the displacement sensor includes:

[0011] S11. Select a laser displacement sensor as the displacement sensor;

[0012] S12. The displacement sensor is installed at an angle on the side of the laser marking machine, and the tilt angle of the displacement sensor is adjustable.

[0013] Furthermore, determining the movement relation includes:

[0014] S21. Set the focusing height of the laser marking machine to h. g Select a flat sheet material with deformation within the set range, and move the laser marking machine to the focusing height h. g To ensure accurate focusing, adjust the tilt angle of the laser displacement sensor so that the centers of the sensor's light spot and the laser marking machine's light spot coincide. Record the z-axis coordinate of the laser marking machine at this point. g And the laser displacement sensor parameters x0, z g The focusing height of the laser marking machine is h g The position coordinates of the laser marking machine when it is accurately focused;

[0015] S22. Control the laser marking machine to move upward a certain distance h. a Read the laser displacement sensor parameter x1 at this time, and use the formula h1 = h g +h a Determine the new height h1 of the laser marking machine;

[0016] S23. Obtain the linear relationship h = kx + b between the laser displacement sensor and the laser marking machine height. Based on the laser displacement sensor parameters x0 and x1, and the set focusing height of the laser marking machine as h... g The new height h1 of the laser marking machine is determined by identifying the coefficients k and b of the linear relationship. Substituting k and b into the linear relationship yields the shift relationship.

[0017] Furthermore, the accurate focusing position determination of the laser marking machine includes:

[0018] S31. Read the current laser displacement sensor parameter x2 and determine the actual height h of the laser marking machine using the aforementioned motion relationship. tDetermine whether the deformation of the current area of ​​the plate exceeds the deformation threshold range. If yes, proceed to step S32. If no, the current position of the laser marking machine is the accurate focusing position, and the position of the laser marking machine does not need to be adjusted.

[0019] S32. According to the set focusing height h of the laser marking machine g And the actual height h of the laser marking machine t Determine the height Δh that the laser marking machine needs to be adjusted, and then determine the position coordinates z of the laser marking machine when it is accurately focused. r According to the position coordinates z r Adjust the position of the laser marking machine.

[0020] Furthermore, the displacement sensor is mounted on the laser marking machine via a bracket;

[0021] The angle of the bracket is adjustable.

[0022] Furthermore, in the linear relationship formula h=kx+b, k=(h1-h g ) / (x1-x0)=h a / (x1-x0); b=k*x0-h g .

[0023] Furthermore, the actual height h of the laser marking machine t = k*x2+b.

[0024] Furthermore, the height Δh that the laser marking machine needs to adjust is determined using the formula Δh = h g -h t Sure.

[0025] Furthermore, the position coordinates of the laser marking machine when it is accurately focused are zr = z g +Δh,

[0026] Among them, z r To determine the correct coordinates that the corrected laser marking machine needs to locate, z g The focusing height of the laser marking machine is h g The position coordinates of the laser marking machine when it is accurately focused.

[0027] In a second aspect of the present invention, a laser marking focusing device for sheet metal parts is disclosed, the device comprising:

[0028] The sensor module uses a displacement sensor installed on the laser marking machine to acquire displacement parameters when the laser marking machine moves.

[0029] The movement relationship determination module is used to acquire parameters from multiple sets of displacement sensors and the laser marking machine during movement, and to determine the movement relationship.

[0030] The laser marking machine accurate focusing position determination module is used to determine the position coordinates of the laser marking machine when it is accurately focused according to the movement relationship formula, and to adjust the position of the laser marking machine.

[0031] As can be seen from the above technical solution, this invention is designed for a horizontal laser marking machine tool used to mark sheet metal parts. Since the allowable deviation range for the focusing distance of the laser machine in the vertical direction is ±0.5mm, when the warping deformation of large sheet metal parts exceeds this tolerance, the laser marking machine will be unable to focus, resulting in unclear QR codes. This invention easily solves the problem by adding a displacement sensor without affecting other functions of the machine, ensuring accurate laser marking focus. Attached Figure Description

[0032] Figure 1 This is a picture of the actual metal sheet.

[0033] Figure 2 This is an overall structural diagram of a laser marking machine;

[0034] Figure 3 This is a diagram illustrating how the marking machine cannot focus when the sheet material is deformed.

[0035] Figure 4 This is a flowchart of the laser marking and focusing method for sheet metal parts in this invention;

[0036] Figure 5 This is a diagram showing the installation location of the displacement sensor;

[0037] Figure 6 This is a diagram illustrating measurement error.

[0038] in:

[0039] 1. Lateral movement assembly, 2. Longitudinal movement assembly, 3. Lifting assembly, 4. Bed assembly. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings:

[0041] This invention aims to solve the problem of laser marking machines failing to accurately focus due to deformation of sheet metal parts during laser marking. For example, sheet metal parts... Figure 1 As shown, the sheet metal part is 6m*2m in size and has a small thickness, making it prone to warping and deformation during cutting, production, and handling.

[0042] The structure of a laser marking machine is as follows Figure 2As shown, the system comprises four main parts: a bed assembly 4, a transverse traverse assembly 1, a longitudinal traverse assembly 2, and a lifting assembly 3. The movement of the transverse traverse assembly 1, longitudinal traverse assembly 2, and lifting assembly 3 enables the marking device to reach any position in X, Y, and Z space. The laser marking machine that performs the marking is mounted on the lifting assembly 3, with the sheet metal parts laid flat on the bed. This invention primarily focuses on adjusting the Z-axis position of the equipment during operation.

[0043] The aforementioned sheet metal deformation problem is as follows: Figure 3 As shown, the present invention is used to solve the problem of controlling a laser marking machine to move to the correct position by relying on the measurement and subsequent calculation of a laser displacement sensor.

[0044] like Figure 4 The method shown is a laser marking focusing method for sheet metal parts, which includes:

[0045] S1. Selection and installation of displacement sensors

[0046] Select a suitable displacement sensor, choose a suitable installation position on the laser marking machine, and adjust the laser displacement sensor to a suitable tilt angle. In this embodiment, a laser displacement sensor is selected; the displacement sensor is installed on the side of the laser marking machine, and an adjustable bracket is fixed to the side of the machine. The sensor is fixed on the bracket, which can rotate a certain angle, such as... Figure 5 As shown. The bracket can be an adjustable bracket from existing technology, as long as it ensures that the laser displacement sensor can be fixed to the bracket. The laser displacement sensor is installed at an angle relative to the laser marking machine. Furthermore, the tilt angle of the laser displacement sensor can be adjusted by rotating the bracket.

[0047] Due to space limitations on sheet metal parts requiring marking, the QR codes printed by the laser marking machine must be relatively small (specifically 10mm*10mm) while carrying a large amount of information. To ensure accurate and clear scanning, the black and white pixels in the QR code must have high clarity. Therefore, the focus deviation of the laser marking machine is limited to ±0.5mm to guarantee the clarity of the printed QR code. However, if the sensor uses a standard offset mounting method, the laser marking machine cannot adjust to a precise focus height. The main innovation of this invention lies in the adjustable tilt mounting method of the sensor. By tilting the displacement sensor and allowing its tilt angle to be adjusted, the above problem can be solved, enabling the laser marking machine to adjust to a precise focus height and ensuring that the printed QR code clarity meets the requirements.

[0048] S2. Determination of the movement relation

[0049] By controlling the movement of the laser marking machine and the laser displacement sensor fixed on it, multiple sets of parameters of the displacement sensor and the laser marking machine during movement are obtained, and the movement relationship is determined.

[0050] S21. Set the focusing height of the laser marking machine to h. g Select a flat sheet material with deformation within the set range, and move the laser marking machine to the focusing height h. g To ensure accurate focusing, adjust the laser displacement sensor so that the center of the sensor's laser spot coincides with the center of the laser marking machine's laser spot, and record the laser marking machine's position at this point. z z-axis coordinate g And the laser displacement sensor parameters x0, z g The focusing height of the laser marking machine is h g The position coordinates of the laser marking machine when it is accurately focused;

[0051] S22. Control the laser marking machine to move upward a certain distance h. a Read the laser displacement sensor parameter x1 at this time, and use the formula h1 = h g +h a Determine the new height h1 of the laser marking machine;

[0052] S23. Obtain the linear relationship h = kx + b between the laser displacement sensor and the laser marking machine height. Based on the laser displacement sensor parameters x0 and x1, and the set focusing height of the laser marking machine as h... g The new height h1 of the laser marking machine determines the coefficients k and b of the linear relationship, where k = (h1 - h g ) / (x1-x0)=h a / (x1-x0); b=k*x0-h g Substituting k and b into the linear relation, we obtain the shift relation.

[0053] S3. Accurate focusing position determination of the laser marking machine.

[0054] Based on the aforementioned movement relationship, the position coordinates of the laser marking machine when it is accurately focused are determined, and the position of the laser marking machine is adjusted accordingly. The adjustment formula is derived by combining the movement relationship with the motion law of the laser marking machine during operation.

[0055] S31. Read the current laser displacement sensor parameter x2 and determine the actual height h of the laser marking machine using the aforementioned motion relationship. t Determine whether the deformation of the current area of ​​the plate exceeds the deformation threshold range. If yes, proceed to step S32. If no, the current position of the laser marking machine is the accurate focusing position, and the position of the laser marking machine does not need to be adjusted.

[0056] S32. According to the set focusing height h of the laser marking machine g And the actual height h of the laser marking machine t Determine the height Δh that the laser marking machine needs to be adjusted, and then determine the position coordinates z of the laser marking machine when it is accurately focused. r According to the position coordinates z r Adjust the position of the laser marking machine. When the warping deformation of the board exceeds the tolerance, first read the sensor parameter x, and then use the above formula to obtain the actual height of the laser marking machine, i.e., h. t =kx+b, and then the height can be calculated using the following formula: Δh=h g -h t Finally, the coordinate z that the coding machine needs to move to is obtained. r =z g +Δh, where z r To determine the correct coordinates that the corrected laser marking machine needs to locate, z g The coordinates of the laser marking machine at the precise focusing point (the height of the marking machine at this point is h) are already recorded. g ).

[0057] In existing technologies, when a laser marking machine cannot focus, a detection device is typically added to detect the deformation of the sheet metal and adjust the height of the marking machine. However, due to space limitations, there is a discrepancy between the detection height of the laser displacement sensor and the time distance between the laser marking machine and the sheet metal. This is the conventionally conceivable offset installation method. When the sheet metal deformation is large and the QR codes are small in size but contain a large amount of information, this offset installation of the detection sensor cannot meet the focusing accuracy requirements. Therefore, this invention proposes to use an inclined installation method for the laser displacement sensor, along with a corresponding calculation formula, which significantly improves the detection accuracy of the actual distance between the marking machine and the sheet metal. This achievement is the result of creative effort.

[0058] The measurement error of the laser displacement sensor under tilted installation is analyzed below and compared with that under offset installation. The measurement errors of the laser displacement sensor under tilted installation and offset installation are as follows: Figure 6 As shown.

[0059] (I) Measurement error when the laser displacement sensor is installed at an angle

[0060] exist Figure 6 In the figure, Δz represents the measurement error when the device is installed at an angle. The magnitude of this error depends on the degree of warping at that location and the angle between the laser displacement sensor and the laser marking machine.

[0061] If we consider the portion between the actual measurement point and the marking point when the laser displacement sensor is installed at an angle as a straight line, then we have: Δz≈(z m -zg )·tanθ·tanα, where, as Figure 6 As shown, z m The height is measured by sensors and then calculated using a motion relationship formula; z g Let θ be the accurate focusing height of the given laser marking machine; θ is the angle between the displacement sensor and the laser marking machine, which is a fixed angle after the laser sensor is installed and adjusted, and tanθ = d / z g ;d is the parallel distance between the sensor and the laser marking machine. Due to the size limitations of the laser marking machine and the sensor, d must be at least 70mm; z g Given a value of 460mm, tanθ is approximately 0.15, and α is the horizontal angle after the plate deforms. Even if α reaches 2°, and (z m -z g When the deformation of the sheet material reaches 10mm, the calculated Δz is approximately 0.05mm, which is within the allowable deviation range of the laser marking machine. Therefore, the error of the laser displacement sensor when installed at an angle meets the marking requirements.

[0062] (II) Measurement error when the laser displacement sensor is installed with an offset orientation

[0063] When the laser displacement sensor is installed using a conventional offset mounting, the sensor measurement path is as follows: Figure 6 In the diagram, X' and the path Z of the laser marking machine are parallel. For example... Figure 6 The error is illustrated, with the measurement error being Δz′. Since α remains the horizontal angle after the plate deformation, the error Δz′ = d·tanα; substituting the data, we get 2.4 mm. Also, because tanθ = d / z... g Therefore, the tilt installation error / offset installation error is: Δz / Δz′ ≈ (z m -z g ) / z g That is, deformation amount / accurate focusing height. The deformation amount is the height difference between the deformed and undeformed positions on the board. Based on the above values, the board deformation amount is 10mm, z g Given a value of 460mm, the error of the laser displacement sensor when installed at an angle is only 1 / 46 of that when installed at a conventional offset.

[0064] Therefore, from Figure 6 As can be seen from the above error calculation results, the laser displacement sensor can meet the marking requirements when installed at an angle, and it is more adaptable and has a smaller error than when installed at an offset.

[0065] The present invention also discloses a laser marking focusing device for sheet metal parts, the device comprising:

[0066] The sensor module uses a displacement sensor installed on the laser marking machine to acquire displacement parameters when the laser marking machine moves.

[0067] The movement relationship determination module is used to acquire parameters from multiple sets of displacement sensors and the laser marking machine during movement, and to determine the movement relationship.

[0068] The laser marking machine accurate focusing position determination module is used to determine the position coordinates of the laser marking machine when it is accurately focused according to the movement relationship formula, and to adjust the position of the laser marking machine.

[0069] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A laser marking focusing method for sheet metal parts, characterized in that, The method includes: S1. Selection and installation of displacement sensor: Select displacement sensor and determine the installation position of displacement sensor on laser marking machine; S2. Determination of the movement relationship: Obtain parameters from multiple sets of displacement sensors and laser marking machine during movement, and determine the movement relationship; S3. Determining the accurate focusing position of the laser marking machine: Based on the aforementioned movement formula, determine the position coordinates of the laser marking machine when it is accurately focused, and adjust the position of the laser marking machine accordingly; Determining the movement relation includes: S21. Set the focusing height of the laser marking machine to h. g Select a flat sheet material with deformation within the set range, and move the laser marking machine to the focusing height h. g To ensure accurate focusing, adjust the tilt angle of the laser displacement sensor so that the centers of the sensor's light spot and the laser marking machine's light spot coincide. Record the z-axis coordinate of the laser marking machine at this point. g And the laser displacement sensor parameters x0, z g The focusing height of the laser marking machine is h g The position coordinates of the laser marking machine when it is accurately focused; S22. Control the laser marking machine to move upward a certain distance h. a Read the laser displacement sensor parameter x1 at this time, and use the formula h1 = h g +h a Determine the new height h1 of the laser marking machine; S23. Obtain the linear relationship h = kx + b between the laser displacement sensor and the laser marking machine height. Based on the laser displacement sensor parameters x0 and x1, and the set focusing height of the laser marking machine as h... g The new height h1 of the laser marking machine is determined by identifying the coefficients k and b of the linear relationship. Substituting k and b into the linear relationship yields the shift relationship.

2. The method according to claim 1, characterized in that, The selection and installation of the displacement sensor includes: S11. Select a laser displacement sensor as the displacement sensor; S12. The displacement sensor is installed at an angle on the side of the laser marking machine, and the tilt angle of the displacement sensor is adjustable.

3. The method according to claim 1, characterized in that, The laser marking machine accurately focuses on a specific position, including: S31. Read the current laser displacement sensor parameter x2 and determine the actual height h of the laser marking machine using the aforementioned motion relationship. t Determine whether the deformation of the current area of ​​the plate exceeds the deformation threshold range. If yes, proceed to step S32. If no, the current position of the laser marking machine is the accurate focusing position, and the position of the laser marking machine does not need to be adjusted. S32. According to the set focusing height h of the laser marking machine g And the actual height h of the laser marking machine t Determine the height Δh that the laser marking machine needs to be adjusted, and then determine the position coordinates z of the laser marking machine when it is accurately focused. r According to the position coordinates z r Adjust the position of the laser marking machine.

4. The method according to claim 2, characterized in that, The displacement sensor is mounted on the laser marking machine via a bracket; The angle of the bracket is adjustable.

5. The method according to claim 1, characterized in that, In the linear relationship h=kx+b, k=(h1-h g ) / (x1-x0)=h a / (x1-x0); b=k*x0-h g .

6. The method according to claim 3, characterized in that, The actual height h of the laser marking machine t = k*x2+b.

7. The method according to claim 6, characterized in that, The height Δh that the laser marking machine needs to be adjusted using the formula Δh = h g -h t Confirmed; where Δh is the height that the laser marking machine needs to be adjusted to; h g h is the focusing height of the laser marking machine. t This refers to the actual height of the laser marking machine.

8. The method according to claim 7, characterized in that, The position coordinate z of the laser marking machine when it is accurately focused r =z g +Δh; Among them, z r To determine the correct coordinates that the corrected laser marking machine needs to locate, z g The focusing height of the laser marking machine is h g The position coordinates of the laser marking machine when it is accurately focused.

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