Rapid positioning method and device for laser focusing position

Abstract

The invention provides a laser focusing position rapid positioning method and device, and the method comprises the steps: determining the motion resolution and the initial position of laser focusing position positioning, controlling a laser galvanometer system to move to the initial position, and controlling the laser galvanometer system to move for multiple times in the direction perpendicular to a machining plane based on the motion resolution. When the laser galvanometer system moves to a target position every time, the laser galvanometer system is controlled to process a marking line on the processing plane and acquire the line width of the marking line; and when the line width corresponding to the current target position is smaller than the line width corresponding to the previous target position and the line width corresponding to the next target position and the distance between every two adjacent target positions in the last three target positions is the motion resolution, the laser galvanometer system is controlled to stop moving. And the position where the laser used for machining the marking line corresponding to the current target position intersects with the machining plane serves as the laser focusing position. According to the invention, the efficiency and accuracy of finding the laser focusing position can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing, and in particular to a method and a device for quickly locating a laser focus position. Background Art

[0002] In the field of high-precision laser processing, due to the stringent requirements on precision indicators, it is necessary to improve the accuracy of each item that has a greater impact on the overall accuracy in an all-round and multi-channel manner. For laser processing systems that achieve laser deflection through galvanometers, it is usually necessary to comprehensively improve the laser processing accuracy through the following approaches: the first step is to collimate the optical path to ensure that the laser light is perpendicular to the processing plane in the initial state of the processing system; the second step is to accurately adjust the focus after the first step is completed to ensure that the laser focus waist position is located inside the processing reference plane in the initial state of the processing system; the third step is to correct the distortion of the galvanometer by measuring multiple times and updating the iterative correction table to reduce the distortion error of the galvanometer. It can be seen that accurately adjusting the position of the laser focus has an important impact on the processing quality and is a very important link in improving the accuracy of laser processing.

[0003] However, the conventional laser focus position adjustment method is not clear in the direction and ideas of adjustment, so it is easy to jump back and forth near the laser focus position, which makes the efficiency of finding the laser focus position low, and the positioning accuracy of the focus position is difficult to guarantee. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a method and device for quickly locating a laser focus position, so as to alleviate the above-mentioned problems existing in the existing laser focus position adjustment technology.

[0005] In a first aspect, an embodiment of the present invention provides a method for quickly locating a laser focus position, comprising: determining a motion resolution of the laser focus position based on a target accuracy of the laser focus position, a preset motion resolution of a platform for driving a laser galvanometer system to move up and down, and a focal depth of a laser beam; determining an initial position of the laser focus position based on a working distance of a field lens, and controlling the laser galvanometer system to move to the initial position; controlling the laser galvanometer system to move multiple times in a direction perpendicular to a processing plane based on the motion resolution, so as to control the laser galvanometer system to process a line on the processing plane each time the laser galvanometer system moves to the target position. Marking a line and obtaining the line width of the marked line; wherein, after each movement of the laser galvanometer system and completion of the marking line processing, the next target position is determined based on the current moving direction of the laser galvanometer system and the line widths corresponding to the current target position and the previous target position; until the line width corresponding to the current target position is smaller than the line widths corresponding to the previous target position and the next target position, and the distances between each two adjacent target positions in the last three target positions are the motion resolution, the laser galvanometer system is controlled to stop moving, and the position where the laser used to process the marking line corresponding to the current target position intersects with the processing plane is used as the laser focusing position.

[0006] In a second aspect, an embodiment of the present invention further provides a laser focus position rapid positioning device, comprising: a determination module, for determining the motion resolution of the laser focus position positioning based on the target accuracy of the laser focus position positioning, the preset motion resolution of the machine platform for driving the laser galvanometer system to move up and down, and the focal depth of the laser beam; a first control module, for determining the initial position of the laser focus position positioning based on the working distance of the field lens, and controlling the laser galvanometer system to move to the initial position; a second control module, for controlling the laser galvanometer system to move multiple times in a direction perpendicular to the processing plane based on the motion resolution, so as to control the laser galvanometer system to move to the target position each time the laser galvanometer system moves to the target position. A marking line is processed on a processing plane and the line width of the marking line is obtained; wherein, after each movement of the laser galvanometer system and completion of the marking line processing, the next target position is determined based on the current moving direction of the laser galvanometer system and the line widths corresponding to the current target position and the previous target position; a positioning module is used to control the laser galvanometer system to stop moving until the line width corresponding to the current target position is smaller than the line width corresponding to the previous target position and the next target position and the distance between each adjacent two target positions in the last three target positions is the motion resolution, and the position where the laser used to process the marking line corresponding to the current target position intersects with the processing plane is used as the laser focusing position.

[0007] The embodiment of the present invention provides a method and device for quickly locating a laser focus position, which determines the motion resolution and initial position of the laser focus position positioning and controls the laser galvanometer system to move to the initial position, and controls the laser galvanometer system to move multiple times in a direction perpendicular to the processing plane based on the motion resolution, so that each time the laser galvanometer system moves to the target position, the laser galvanometer system is controlled to process a marking line on the processing plane and obtain the line width of the marking line, until the line width corresponding to the current target position is less than the line width corresponding to the previous target position and the next target position, and the distance between each two adjacent target positions in the last three target positions is the motion resolution, the laser galvanometer system is controlled to stop moving, and the position where the laser used to process the marking line corresponding to the current target position intersects with the processing plane is used as the laser focus position. By adopting the above technology, the motion resolution of the laser focus position positioning can be used to control the laser galvanometer system to move to different positions to form multiple marking lines on the processing plane, and by comparing the line widths of different marking lines, a more accurate laser focus position can be quickly found, which can improve the efficiency and accuracy of finding the laser focus position, thereby ensuring the laser processing accuracy.

[0008] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0009] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0011] Figure 1 Schematic diagram of a process of a method for quickly locating a laser focus position in an embodiment of the present invention;

[0012] Figure 2 A schematic diagram of a scene for rapid positioning of a laser focus position in an embodiment of the present invention;

[0013] Figure 3 This is a schematic diagram of a coarse positioning process in an embodiment of the present invention;

[0014] Figure 4This is a schematic diagram of the precise positioning process in an embodiment of the present invention;

[0015] Figure 5 Schematic diagram of the structure of a laser focus position rapid positioning device in an embodiment of the present invention. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described in combination with the embodiments below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] At present, in the field of high-precision laser processing, accurately adjusting the laser focus position is a very important link in improving laser processing accuracy. However, the conventional laser focus position adjustment method is easy to jump back and forth near the laser focus position due to unclear adjustment direction and ideas, and the efficiency of finding the laser focus position is low. At the same time, the positioning accuracy of the focus position is difficult to guarantee.

[0018] Based on this, the present invention provides a method and device for quickly locating a laser focus position, which can alleviate the above-mentioned problems existing in the existing laser focus position adjustment technology.

[0019] See also Figure 1 As shown, the laser focus position rapid positioning method may include the following steps:

[0020] Step S102 , determining the motion resolution of the laser focus position positioning based on the target accuracy of the laser focus position positioning, the preset motion resolution of the platform for driving the laser galvanometer system to move up and down, and the focal depth of the laser beam.

[0021] The preset motion resolution represents the minimum allowable motion step length of the machine-driven laser galvanometer system to move up and down.

[0022] See also Figure 2 As shown, the laser galvanometer system 201 can be driven to move up and down perpendicular to the processing plane 202 by the external axis 205 (i.e., the axis on the machine platform used to drive the laser galvanometer system 201 to move up and down). During actual laser processing, the laser galvanometer system 201 needs to ensure that the laser focal point 204 is on the processing plane 202 as much as possible to ensure the laser processing accuracy. The motion resolution MinStepLength in the focusing and positioning process is determined by three factors: the motion resolution ShaftResolution of the external axis 205, the focusing and positioning accuracy requirement PosPrecision, and the focal depth DOF of the laser beam.

[0023] Step S104, determining the initial position of the laser focus position based on the working distance of the field lens, and controlling the laser galvanometer system to move to the initial position.

[0024] Continuing from the previous example, see Figure 2 As shown, a theoretical position can be determined according to the working distance of the field lens as the initial position for positioning the laser focus position. The distance between the initial position and the field lens is equal to the working distance of the field lens. Moving the laser galvanometer system 201 to the initial position can ensure that the laser focus point 204 is on the processing plane 202, thereby ensuring the laser processing accuracy.

[0025] Step S106, based on the motion resolution, controls the laser galvanometer system to move multiple times in a direction perpendicular to the processing plane, so as to control the laser galvanometer system to process a marking line on the processing plane and obtain the line width of the marking line each time the laser galvanometer system moves to the target position.

[0026] After the laser galvanometer system moves and completes the marking line processing each time, the next target position is determined based on the current moving direction of the laser galvanometer system and the line widths corresponding to the current target position and the previous target position.

[0027] Continuing from the previous example, see Figure 2 As shown, the laser of the laser galvanometer system 201 is turned on, and the laser 203 marks a straight line with a certain line width on the processing plane 202. The straight line is the marking line. The line width of the straight line can reflect the range of the laser 203 being cut off by the processing plane 202. When the laser focal point 204 is on the processing plane 202, the range of the laser 203 being cut off by the processing plane 202 is the smallest. Therefore, the process of finding the laser focal point 204 can be converted into finding the position along the emission direction of the laser 203 that minimizes the range of the laser 203 being cut off by the processing plane 202.

[0028] Step S108, until the line width corresponding to the current target position is smaller than the line width corresponding to the previous target position and the next target position respectively and the distance between each adjacent target position in the last three target positions is the motion resolution, the laser galvanometer system is controlled to stop moving, and the position where the laser used to process the marking line corresponding to the current target position intersects with the processing plane is used as the laser focusing position.

[0029] Continuing from the previous example, see Figure 2As shown, in the process of driving the laser galvanometer system 201 to move up and down perpendicular to the processing plane 202 by the external shaft 205, the laser galvanometer system 201 will turn on the laser to emit laser 203 every time it reaches a target position to mark a marking line on the processing plane 202. If a target position and other target positions adjacent to it satisfy that the line width of the marking line corresponding to the target position is smaller than the line width of the marking lines corresponding to other target positions and the distances between the target position and other target positions adjacent to it are the motion resolution MinStepLength, it means that the laser focus point 204 is near the target position and the distance between the laser focus point 204 and the target position is less than the motion resolution MinStepLength. The position where the laser 203 used by the laser galvanometer system 201 to mark the marking line at the target position intersects with the processing plane 202 (i.e., the intersection of the laser 203 and the processing plane 202) can be used as the laser focus position, so that the laser processing accuracy can be guaranteed when laser processing is performed at the laser focus position later.

[0030] The embodiment of the present invention provides a method for fast positioning of a laser focus position, which determines the motion resolution and initial position of the laser focus position positioning and controls the laser galvanometer system to move to the initial position, and controls the laser galvanometer system to move multiple times in a direction perpendicular to the processing plane based on the motion resolution, so that each time the laser galvanometer system moves to the target position, the laser galvanometer system is controlled to process a marking line on the processing plane and obtain the line width of the marking line, until the line width corresponding to the current target position is less than the line width corresponding to the previous target position and the next target position respectively, and the distance between each two adjacent target positions in the last three target positions is the motion resolution, the laser galvanometer system is controlled to stop moving, and the position where the laser used to process the marking line corresponding to the current target position intersects with the processing plane is used as the laser focus position. By adopting the above technology, the motion resolution of the laser focus position positioning can be used to control the laser galvanometer system to move to different positions to form multiple marking lines on the processing plane, and a relatively accurate laser focus position can be quickly found by comparing the line widths of different marking lines, which can improve the efficiency and accuracy of finding the laser focus position, thereby ensuring the laser processing accuracy.

[0031] As a possible implementation, the above step S106 (i.e., controlling the laser galvanometer system to move multiple times in a direction perpendicular to the processing plane based on the motion resolution, so as to control the laser galvanometer system to process a marking line on the processing plane and obtain the line width of the marking line each time the laser galvanometer system moves to the target position) may include:

[0032] Step 1: determine the initial motion step length of the laser galvanometer system based on the motion resolution.

[0033] The initial motion step size is greater than the motion resolution and is an integer multiple of the motion resolution.

[0034] Continuing from the previous example, see Figure 2 As shown, after obtaining the motion resolution MinStepLength in the focusing positioning process, the step length S of the laser galvanometer system 201 moving up and down perpendicular to the processing plane 202 can be set to N×MinStepLength, where N is an integer, so that each subsequent time the laser galvanometer system 201 is driven by the external axis 205 to move a step length S from the current target position in a direction perpendicular to the processing plane 202 to reach the next target position.

[0035] Step 2: When the laser galvanometer system moves to the first target position, the laser galvanometer system is controlled to process a marking line on the processing plane and obtain the line width of the marking line.

[0036] Step 3, for each target position after the first target position, perform the following steps A to D:

[0037] A. Determine the direction of the next target position based on the current moving direction of the laser galvanometer system and the line widths corresponding to the current target position and the previous target position.

[0038] B. Set the position in the direction of the next target position and the distance from the current target position by the current motion step as the next target position, control the laser galvanometer system to move to the next target position, process a marking line on the processing plane and obtain the line width of the marking line; wherein the current motion step is the initial motion step for the second target position.

[0039] C. If the line width corresponding to the current target position is smaller than the line widths corresponding to the previous target position and the next target position, adjust the current motion step length based on the motion resolution, and use the adjusted motion step length as the motion step length, re-execute steps A and B until the current motion step length reaches the motion resolution and stops adjusting the current motion step length.

[0040] As a possible implementation, the step of determining the direction of the next target position based on the current moving direction of the laser galvanometer system and the line widths corresponding to the current target position and the previous target position may include: if the current target position is the target position reached by the laser galvanometer system for the first time after adjusting the current motion step, then randomly determining a direction that is consistent with or opposite to the current moving direction of the laser galvanometer system as the direction of the next target position; if the current target position is not the target position reached by the laser galvanometer system for the first time after adjusting the current motion step, then comparing the line widths corresponding to the current target position and the previous target position to determine the direction of the next target position.

[0041] In actual application, the operation method of comparing the line widths corresponding to the current target position and the previous target position to determine the direction of the next target position can be: if the line width corresponding to the current target position is smaller than the line width corresponding to the previous target position, then it is determined that the direction of the next target position is consistent with the current moving direction of the laser galvanometer system; if the line width corresponding to the current target position is larger than the line width corresponding to the previous target position, then it is determined that the direction of the next target position is opposite to the current moving direction of the laser galvanometer system.

[0042] As a possible implementation, the above-mentioned step of adjusting the current motion step length based on the motion resolution may include: if the current motion step length is greater than the motion resolution, reducing the current motion step length, and using the reduced motion step length as the adjusted motion step length; if the current motion step length is the motion resolution, keeping the current motion step length unchanged.

[0043] In actual application, the motion step length of the laser galvanometer system each time it moves can be an integer multiple of the motion resolution; based on this, the above-mentioned operation method of reducing the current motion step length can be: determine the reduction amount of the current motion step length, and reduce the current motion step length according to the reduction amount; wherein the reduction amount is an integer multiple of the motion resolution and is not greater than half of the current motion step length.

[0044] As a possible implementation, the ratio between the motion resolution and the depth of focus may be no greater than 0.3; based on this, the above-mentioned step S102 (i.e., determining the motion resolution of the laser focus position positioning based on the target accuracy of the laser focus position positioning, the preset motion resolution of the machine for driving the laser galvanometer system to move up and down, and the focal depth of the laser beam) may include: if the target accuracy is lower than the preset motion resolution, then determining the target accuracy as the motion resolution; if the target accuracy is not lower than the preset motion resolution, then determining the preset motion resolution as the motion resolution.

[0045] Continuing from the previous example, see Figure 2As shown, when the motion resolution ShaftResolution of the external shaft 205, the focus positioning accuracy requirement PosPrecision, and the focal depth DOF of the laser beam are known, if PosPrecision>ShaftResolution, it means that the requirements for positioning accuracy can actually be met, and the motion resolution MinStepLength in the focus positioning process is MinStepLength=PosPrecision. If PosPrecision≤ShaftResolution, it means that the requirements for positioning accuracy are too high and the requirements for positioning accuracy cannot actually be met, then MinStepLength=ShaftResolution, that is, when determining the motion resolution of laser focus position positioning, the accuracy of focus adjustment can only be guaranteed to the maximum extent under the motion resolution of the external shaft 205. In addition, the focal depth of a specific laser beam must also be considered, and generally MinStepLength is less than or equal to 0.3 times the DOF.

[0046] As a possible implementation, the step of obtaining the line width of the marking line may include: measuring the line width of the marking line using a microscope with a preset magnification, or acquiring an image containing the marking line using a visual system and calculating the line width of the marking line based on the image.

[0047] In actual application, the preset magnification is not less than 100. Specifically, a metallographic microscope with a magnification of more than 100 times can be used to measure the line width of the marked line.

[0048] Continuing from the previous example, see Figure 2 As shown, a visual system 206 can be installed on the optical system. The visual system 206 has functions such as image acquisition, recognition of marking lines, and line width calculation. Every time the laser galvanometer system 201 reaches a target position and uses the laser 203 to mark a marking line on the processing plane 202, the visual system 206 can be controlled to automatically acquire an image containing the marking line, recognize the marking line in the image, and calculate the line width of the marking line.

[0049] For ease of understanding, the implementation of the above-mentioned laser focus position rapid positioning method is described as follows by taking a specific application as an example.

[0050] See also Figures 2 to 4 As shown, the above-mentioned laser focus position rapid positioning method can mainly include the following steps:

[0051] Step 1: Determine the motion resolution MinStepLength during the focusing process. This parameter is determined by three factors: ① the motion resolution ShaftResolution of the external shaft 205 (driving the laser galvanometer system 201 to move vertically up and down the processing plane 202); ② the focusing accuracy requirement PosPrecision; ③ the focal depth DOF of the laser 203.

[0052] The direction of the external axis 205 is perpendicular to the processing plane 202 and is upward. The external axis 205 is generally defined as the Z axis.

[0053] If PosPrecision>ShaftResolution, then MinStepLength=PosPrecision; if PosPrecision≤ShaftResolution, then MinStepLength=ShaftResolution; MinStepLength is less than or equal to 0.3 times DOF.

[0054] Step 2: Determine the initial position Z=FocalLength during the focusing positioning process according to the working distance of the field lens.

[0055] The initial position corresponds to the working distance of the field lens. For example, when the working distance of the field lens of the optical system is known, the theoretically accurate value of the laser focus position (i.e., the laser focus point 204) is the position of the working distance. However, due to the accuracy of the processing, manufacturing and installation of related parts, the laser focus position is a random value near the accurate value under actual conditions at the laser processing site. The above-mentioned laser focus position rapid positioning method is to accurately find this random value.

[0056] Step 3: Turn on the laser, the laser 203 emits light and marks a straight line on the processing plane 202.

[0057] Similar to the initial position, the processing plane 202 is also a theoretical position determined according to the working distance. Figure 2 As shown, the processing plane 202 is generally installed on the base of the machine tool (processing system). The processing plane 202 should theoretically be located at the working distance (that is, the distance between the processing plane 202 and the lower surface of the field lens is equal to the working distance) to ensure that the laser focus point 204 is on the processing plane 202.

[0058] Marking refers to processing a straight line as a marking line on the surface of the workpiece on the reference plane (ie, the processing plane 202) using a laser 203.

[0059] Step 4: Get the width of the marking line obtained in step 3 and record it as FirstLineWidth.

[0060] The width of the marking line (i.e. line width) can be measured under a high-precision microscope. The magnification of the microscope is above 100 times. In practice, the magnification of the microscope can be controlled within the range [100,400]. For example, a 150x metallographic microscope can meet the requirements. Figure 2 As shown, the width of the marking line can be considered to be determined by the area of ​​the cross section (corresponding to the light spot formed on the processing plane 202) obtained by truncating the beam of the laser 203 by the processing plane 202. The smaller the width of the marking line, the closer the processing plane 202 is to the laser focus point 204. It is generally believed that the cross section of the laser 203 focusing waist position is the smallest, and the above-mentioned laser focus position rapid positioning method is to find the precise position (i.e., the laser focus position) where the laser 203 focusing cross section is the smallest. Figure 3 and Figure 4 The focus waist of the laser 203 is shown. The cross-sectional area of ​​the focus waist of the laser 203 can be used to represent the marked line width.

[0061] In addition to using a microscope to measure line width, the visual system 206 can also be used to take pictures to measure the line width and automatically return, automatically adjust the external axis 205 to drive the movement of the laser galvanometer system 201, and realize the full automation of the entire focus precision adjustment. According to the focal depth range, the accuracy of the line width measurement by the visual system 206 needs to be above 0.01mm. The method of using the visual system 206 to measure the line width improves the efficiency of line width acquisition, thereby improving the overall efficiency of laser focus position positioning.

[0062] Step 5: Randomly determine a moving direction (upward or downward perpendicular to the processing plane 202), control the laser galvanometer system 201 to move a certain distance (such as 10×MinStepLength), and then repeat the third and fourth steps, record the line width SecondLineWidth, and compare the two line widths FirstLineWidth and SecondLineWidth. If SecondLineWidth>FirstLineWidth, it means that the precise laser focus position is on the opposite side of the moving direction determined in the fifth step, otherwise (i.e. SecondLineWidth≤FirstLineWidth), it means that the precise laser focus position is in the moving direction determined in the fifth step.

[0063] If the precise laser focus position is in the moving direction determined in step 5, then the following steps 6 to 9 are performed after completing steps 1 to 5.

[0064] Step 6: Drive the laser galvanometer system 201 through the external shaft 205 to move a certain distance S (such as 10×MinStepLength) in the moving direction determined in the fifth step, and repeat the third and fourth steps to record the line width.

[0065] Step 7: If the line width recorded in step 6 continues to decrease compared to SecondLineWidth, it means that the actual laser focus position is in the current moving direction. If the line width recorded in step 6 increases compared to SecondLineWidth, it means that the precise laser focus position is in the opposite direction of the current moving direction. See Figure 3 As shown in the figure, repeat the operation n times (i.e., step 3 to step 6) until the line width increases again, completing the first round of rough positioning; at the same time, compare the line widths of the nth and n-2nd times. If the line width obtained by the nth marking is larger than the line width obtained by the n-2nd marking, then the precise laser focus position is between the n-2nd marking position and the n-1st marking position (such as Figure 3 As shown in Figure 2, if the line width obtained by the nth marking is smaller than the line width obtained by the n-2th marking, then the precise laser focus position is between the n-1th marking position and the nth marking position. Figure 3 As shown, it can be seen that after the above series of steps, the theoretical focusing position (ie, the precise laser focusing position) is between the n-2th marking position and the n-1th marking position.

[0066] Step 8: If the laser focus position determined in step 7 is between the n-1th marking position and the nth marking position, the laser galvanometer system 201 is driven by the external shaft 205 to move S / 2 (e.g. 5×MinStepLength) in the opposite direction of the current moving direction from the laser focus position determined in step 7 to mark a straight line. If the laser focus position determined in step 7 is between the n-2th marking position and the n-1th marking position, the laser galvanometer system 201 is driven by the external shaft 205 to move 3S / 2 (e.g. 15×MinStepLength) in the opposite direction of the current moving direction.

[0067] Step 9: Randomly select a direction (upward or downward perpendicular to the processing plane 202) to control the laser galvanometer system 201 to move MinStepLength, and repeat steps 3 and 4. During this process, if the line width continues to decrease, it means that the actual laser focus position is in the direction selected in step 9. The laser galvanometer system 201 can be controlled to continue to move MinStepLength from the current position in this direction. If the line width increases, it means that the precise laser focus position is on the opposite side of the direction selected in step 9. The laser galvanometer system 201 can be controlled to move MinStepLength from the current position in the opposite direction of this direction. Repeat the above operation n times (i.e., control the laser galvanometer system 201 to move MinStepLength and perform steps 3 and 4) until the line width increases again, completing the first round of precise positioning. The actual focus position can be taken as the position of the n-1th mark for precise positioning to complete the search for the laser focus position. The implementation process is as follows: Figure 4 As shown, it can be seen that the position of the precise positioning n-1th marking is very close to the theoretical focus position (ie, the position of the laser focus point 204), meeting the required accuracy MinStepLength.

[0068] The above steps can ensure that the laser light speed focusing position is quickly found under the condition of meeting the focusing positioning accuracy requirement MinStepLength.

[0069] Similarly, if the precise laser focus position is on the opposite side of the moving direction determined in step 5, perform the following steps after completing steps 1 to 5:

[0070] The laser galvanometer system 201 is driven by the external shaft 205 to move 3S / 2 (for example, 15×MinStepLength) in the opposite direction of the moving direction determined in the fifth step, and then a step similar to the sixth step is performed, that is, the laser galvanometer system 201 is driven by the external shaft 205 to continue to move S in the current moving direction and repeat the third and fourth steps to record the line width. Then a step similar to the seventh step is performed, that is, if the currently recorded line width continues to decrease compared to the previously recorded line width, it means that the actual laser focus position is in the current moving direction; if the currently recorded line width increases compared to the previously recorded line width, it means that the precise laser focus position is in the opposite direction of the current moving direction, see Figure 3As shown, the operation is repeated n times or more (i.e., the laser galvanometer system 201 is controlled to move S once and the third and fourth steps are performed to record the line width and then the currently recorded line width is compared with the line width recorded previously) until the line width becomes larger again, and the first round of coarse positioning is completed. At the same time, the line width obtained by the nth marking is compared with the line width obtained by the n-2th marking. If the line width obtained by the nth marking is larger than the line width obtained by the n-2th marking, then the precise laser focusing position is between the n-2th marking position and the n-1th marking position. If the line width obtained by the nth marking is smaller than the line width obtained by the n-2th marking, then the precise laser focusing position is between the n-1th marking position and the nth marking position. Then, a step similar to step 8 is performed, that is, if the laser focus position determined in the previous step is between the n-1th marking position and the nth marking position, the laser galvanometer system 201 is driven by the external shaft 205 to move S / 2 in the opposite direction of the current moving direction from the laser focus position determined in the previous step to mark a straight line, and if the laser focus position determined in the previous step is between the n-2th marking position and the n-1th marking position, the laser galvanometer system 201 is driven by the external shaft 205 to move 3S / 2 in the opposite direction of the current moving direction. Then, step 9 is performed to complete the first round of fine positioning.

[0071] If a second round of precise positioning is involved, the operation method of the second round of precise positioning is the same as that of the first round of precise positioning, which will not be described in detail.

[0072] The above steps mainly illustrate how to find the precise laser focus position through one round of rough positioning and one round of fine positioning. In actual application, rough positioning can be arranged in multiple rounds according to actual conditions (generally 1-2 rounds of rough positioning are sufficient to meet the needs, and then fine positioning is performed). The steps described in the previous article only use one round of rough positioning and one round of fine positioning just for the sake of simplicity. One round of rough positioning and one round of fine positioning combined with the diagram can clearly describe the principle of the above-mentioned laser focus position rapid positioning method, but it does not limit the number of rounds of rough positioning and fine positioning. Generally, when performing the second round of rough positioning, the moving step used for the first marking is 1 / 2 of the moving step used in the previous round of rough positioning. In actual situations, the moving step used in this round of rough positioning is 1 / 4 or less of the moving step used in the previous round of rough positioning. However, in the final fine positioning stage, the distance moved by the laser galvanometer system 201 each time is a fixed MinStepLength, which ensures that the accuracy of laser focus position positioning is within a range of variation of MinStepLength.

[0073] The beneficial effects of the above-mentioned laser focus position rapid positioning method are mainly reflected in the following aspects:

[0074] First, the method is efficient. By continuously narrowing the search range, the method first continuously narrows the precise focus position to a smaller range, and then selects a shorter search step. Through coarse positioning, the efficiency of finding the focus position can be greatly improved.

[0075] Second, high precision. Combining coarse positioning and fine positioning, even if very high precision requirements are set, the precise focus position can be quickly found if the hardware equipment allows, and the focus position with high precision can be easily obtained.

[0076] Third, it is highly flexible. One or more rounds of rough positioning and fine positioning can be set according to different accuracy requirements and hardware equipment conditions to achieve the purpose of efficiently finding the focus position; at the same time, in the fine positioning stage, the search step size can be set arbitrarily according to the required accuracy value and the conditions met by the hardware, so that a high-precision focus position can be easily obtained.

[0077] Based on the above laser focus position rapid positioning method, the embodiment of the present invention also provides a laser focus position rapid positioning device, see Figure 5 As shown, the device may include the following modules:

[0078] The determination module 502 is used to determine the motion resolution of the laser focus position positioning based on the target accuracy of the laser focus position positioning, the preset motion resolution of the machine platform for driving the laser galvanometer system to move up and down, and the focal depth of the laser beam.

[0079] The first control module 504 is used to determine the initial position of the laser focus position positioning based on the working distance of the field lens, and control the laser galvanometer system to move to the initial position.

[0080] The second control module 506 is used to control the laser galvanometer system to move multiple times in a direction perpendicular to the processing plane based on the motion resolution, so as to control the laser galvanometer system to process a marking line on the processing plane and obtain the line width of the marking line each time the laser galvanometer system moves to the target position; wherein, after the laser galvanometer system moves each time and completes the marking line processing, the next target position is determined based on the current moving direction of the laser galvanometer system and the line widths corresponding to the current target position and the previous target position.

[0081] The positioning module 508 is used to control the laser galvanometer system to stop moving until the line width corresponding to the current target position is smaller than the line width corresponding to the previous target position and the next target position respectively and the distance between each two adjacent target positions in the last three target positions is the motion resolution, and use the position where the laser used to process the marking line corresponding to the current target position intersects with the processing plane as the laser focusing position.

[0082] By adopting the above-mentioned laser focusing position rapid positioning device, the motion resolution of laser focusing position positioning can be used to control the laser galvanometer system to move to different positions to form multiple marking lines on the processing plane, and by comparing the line widths of different marking lines, a more precise laser focusing position can be quickly found, which can improve the efficiency and accuracy of finding the laser focusing position, thereby ensuring the laser processing accuracy.

[0083] The ratio between the above-mentioned motion resolution and the above-mentioned depth of focus may not be greater than 0.3; based on this, the above-mentioned determination module 502 may also be used for: if the target accuracy is lower than the preset motion resolution, then the target accuracy is determined as the motion resolution; if the target accuracy is not lower than the preset motion resolution, then the preset motion resolution is determined as the motion resolution.

[0084] The second control module 506 may also be used to: measure the line width of the marking line using a microscope with a preset magnification, or use a visual system to capture an image containing the marking line and calculate the line width of the marking line based on the image.

[0085] The laser focusing position rapid positioning device provided in the embodiment of the present invention has the same implementation principle and technical effects as those in the aforementioned laser focusing position rapid positioning method embodiment. For the sake of brief description, for matters not mentioned in the embodiment of the laser focusing position rapid positioning device, reference may be made to the corresponding contents in the aforementioned laser focusing position rapid positioning method embodiment.

[0086] Unless otherwise specifically stated, the relative steps, numerical expressions and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present invention.

[0087] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0088] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0089] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for quickly locating a laser focus position, characterized in that: include: Determine the motion resolution of the laser focus position positioning based on the target accuracy of the laser focus position positioning, the preset motion resolution of the machine for driving the laser galvanometer system to move up and down, and the focal depth of the laser beam; Determine the initial position of the laser focus position based on the working distance of the field lens, and control the laser galvanometer system to move to the initial position; Based on the motion resolution, the laser galvanometer system is controlled to move multiple times in a direction perpendicular to the processing plane, so that each time the laser galvanometer system moves to the target position, the laser galvanometer system is controlled to process a marking line on the processing plane and obtain the line width of the marking line; wherein, after the laser galvanometer system moves and completes the marking line processing each time, the next target position is determined based on the current moving direction of the laser galvanometer system and the line widths corresponding to the current target position and the previous target position; Until the line width corresponding to the current target position is smaller than the line width corresponding to the previous target position and the next target position respectively and the distance between each adjacent target position in the last three target positions is the motion resolution, the laser galvanometer system is controlled to stop moving, and the position where the laser used to process the marking line corresponding to the current target position intersects with the processing plane is used as the laser focusing position.

2. The laser focus position rapid positioning method according to claim 1, characterized in that: Based on the motion resolution, the laser galvanometer system is controlled to move multiple times in a direction perpendicular to the processing plane, so that each time the laser galvanometer system moves to a target position, the laser galvanometer system is controlled to process a marking line on the processing plane and obtain the line width of the marking line, including: Determining an initial motion step length of the laser galvanometer system based on the motion resolution; wherein the initial motion step length is greater than the motion resolution and is an integer multiple of the motion resolution; When the laser galvanometer system moves to the first target position, the laser galvanometer system is controlled to process a marking line on the processing plane and obtain the line width of the marking line; For each target position after the first, perform the following steps A through D: A. Determine the direction of the next target position based on the current moving direction of the laser galvanometer system and the line widths corresponding to the current target position and the previous target position; B. Taking the position in the direction of the next target position and the distance from the current target position by the current motion step length as the next target position, controlling the laser galvanometer system to move to the next target position to process a marking line on the processing plane and obtain the line width of the marking line; wherein the current motion step length is the initial motion step length for the second target position; C. If the line width corresponding to the current target position is smaller than the line widths corresponding to the previous target position and the next target position respectively, adjust the current motion step length based on the motion resolution, and use the adjusted motion step length as the motion step length, re-execute steps A and B, and stop adjusting the current motion step length when the current motion step length is the motion resolution.

3. The laser focus position rapid positioning method according to claim 2, characterized in that: Adjusting the current motion step size based on the motion resolution includes: If the current motion step length is greater than the motion resolution, the current motion step length is reduced, and the reduced motion step length is used as the adjusted motion step length; If the current motion step length is the motion resolution, the current motion step length is kept unchanged.

4. The laser focus position rapid positioning method according to claim 2, characterized in that: Based on the current moving direction of the laser galvanometer system and the line widths corresponding to the current target position and the previous target position, the direction of the next target position is determined, including: If the current target position is the target position that the laser galvanometer system reaches for the first time after adjusting the current motion step length, then the direction that is consistent with or opposite to the current moving direction of the laser galvanometer system is randomly determined as the direction of the next target position; If the current target position is not the target position reached by the laser galvanometer system for the first time after adjusting the current motion step, the line widths corresponding to the current target position and the previous target position are compared to determine the direction of the next target position.

5. The laser focus position rapid positioning method according to claim 4, characterized in that: Compare the line widths corresponding to the current target position and the previous target position to determine the direction of the next target position, including: If the line width corresponding to the current target position is smaller than the line width corresponding to the previous target position, it is determined that the direction of the next target position is consistent with the current moving direction of the laser galvanometer system; If the line width corresponding to the current target position is greater than the line width corresponding to the previous target position, it is determined that the direction of the next target position is opposite to the current moving direction of the laser galvanometer system.

6. The laser focus position rapid positioning method according to claim 3, characterized in that: The motion step length of the laser galvanometer system each time it moves is an integer multiple of the motion resolution; Reduce the current motion step size, including: Determine a reduction amount of the current motion step length, and reduce the current motion step length according to the reduction amount; wherein the reduction amount is an integer multiple of the motion resolution and is not greater than half of the current motion step length.

7. The laser focus position rapid positioning method according to claim 1, characterized in that: The ratio of the motion resolution to the focal depth is not greater than 0.3; the motion resolution of the laser focus position positioning is determined based on the target accuracy of the laser focus position positioning, the preset motion resolution of the machine for driving the laser galvanometer system to move up and down, and the focal depth of the laser beam, including: If the target accuracy is lower than the preset motion resolution, determining the target accuracy as the motion resolution; If the target accuracy is not lower than the preset motion resolution, the preset motion resolution is determined as the motion resolution.

8. The laser focus position rapid positioning method according to claim 1, characterized in that: Get the line width of the marking line, including: The line width of the scribed line is measured using a microscope at a preset magnification, or a vision system is used to capture an image containing the scribed line and calculate the line width of the scribed line based on the image.

9. The laser focus position rapid positioning method according to claim 8, characterized in that: The preset magnification is not less than 100.

10. A laser focus position rapid positioning device, characterized in that: include: A determination module, for determining a motion resolution of the laser focus position positioning based on a target accuracy of the laser focus position positioning, a preset motion resolution of a machine platform for driving the laser galvanometer system to move up and down, and a focal depth of the laser beam; A first control module, used to determine an initial position of the laser focus position based on the working distance of the field lens, and control the laser galvanometer system to move to the initial position; The second control module is used to control the laser galvanometer system to move multiple times in a direction perpendicular to the processing plane based on the motion resolution, so as to control the laser galvanometer system to process a marking line on the processing plane and obtain the line width of the marking line each time the laser galvanometer system moves to the target position; wherein, after the laser galvanometer system moves and completes the marking line processing each time, the next target position is determined based on the current moving direction of the laser galvanometer system and the line widths corresponding to the current target position and the previous target position; The positioning module is used to control the laser galvanometer system to stop moving until the line width corresponding to the current target position is smaller than the line width corresponding to the previous target position and the next target position respectively and the distance between each two adjacent target positions in the last three target positions is the said motion resolution, and the position where the laser used to process the marking line corresponding to the current target position intersects with the processing plane is used as the laser focusing position.

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