Laser ranging optical assembly and laser processing system

Abstract

The invention belongs to the field of laser processing, and relates to a laser ranging optical assembly and a laser processing system, and the laser ranging optical assembly comprises a coaxial range finder and a light beam translation module which is located on the same light path with the coaxial range finder. The laser ranging optical assembly and the laser processing system are good in measurement accuracy and high in measurement precision.

Description

Technical Field

[0001] The invention belongs to the field of laser processing and relates to a laser ranging optical component and a laser processing system. Background Art

[0002] At present, with the continuous development of laser technology, various characteristics of lasers have been applied to many fields, among which laser technology has developed rapidly in the field of distance measurement. At present, most projects are using laser rangefinders for distance measurement, precisely because the high accuracy and high timeliness of laser rangefinders have brought great convenience to people. In laser processing, it is often necessary to accurately measure the exact position of the laser workpiece and the focus to ensure accurate processing in the workpiece. In order to better protect the workpiece, more and more workpieces will be coated before laser processing, and laser processing will begin after the coating is completed. Since the type of coating material and the degree of coating will cause surface roughness and laser scattering, it is easy to cause inaccurate measurement.

[0003] For example, in the invention application with application number 201810165427.5, a thickness measuring device based on the laser triangulation displacement measurement method is disclosed. The thickness is measured by dual laser triangulation displacement. The lasers emitted by two semiconductor lasers of different wavelengths are respectively irradiated to the surfaces of both sides of the object, and the thickness of the object in motion or vibration is accurately measured by photoelectric non-contact. However, the patent measurement system uses two upper and lower laser displacement sensors, which makes the composition complex, the cost high, and the device structure large. Moreover, most of the energy is reflected or projected after the laser is vertically incident, the imaging waveform amplitude will be very low, and the measurement accuracy is poor. At the same time, the thickness measurement problem caused by different distances has not been overcome, which is not desirable. At the same time, in the invention application with publication number CN113210360A, a cleaning device is disclosed. This solution is mainly for metals that can be measured conventionally, and cannot achieve the improvement of the measurement accuracy of coated materials. In the invention application with publication number CN111360396A, optical fiber is mainly used to recover the signal in the optical path for measurement. Due to the inconsistency of the surface roughness and granularity of the coating, this solution also cannot solve the problem of achieving the measurement accuracy of coated materials. In the invention application with the publication number CN104748721A, due to the depth of field error of the visual camera itself, there is no way to achieve the measurement effect for high-precision measurement. Obviously, in the prior art, due to the influence of the thickness and roughness of the surface coating of the material, it is impossible to measure the processing distance of materials with different coatings with high precision. Summary of the invention

[0004] In order to solve the above technical problems existing in the background technology, the present invention provides a laser ranging optical component and a laser processing system with good measurement accuracy and high measurement precision.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A laser distance measurement optical component, characterized in that: the laser distance measurement optical component comprises a coaxial distance meter and a light beam translation module on the same optical path as the coaxial distance meter.

[0007] The above-mentioned beam translation module comprises a motor and a glass sheet; the glass sheet and the coaxial rangefinder are in the same optical path; the motor is connected to the glass sheet and drives the glass sheet to tilt on two axes.

[0008] The motor includes a first motor and a second motor; the first motor and the second motor are connected to the glass sheet respectively; the first motor drives the glass sheet to tilt on the Y axis; the second motor drives the glass sheet to tilt on the Z axis.

[0009] The first motor drives the glass sheet to tilt at an angle of ±30° on the Y axis; the second motor drives the glass sheet to tilt at an angle of ±30° on the Z axis.

[0010] A distance measurement method based on the laser distance measurement optical component as described above, characterized in that the distance measurement method comprises the following steps:

[0011] 1) The coaxial rangefinder emits a ranging laser, which is transmitted through the glass sheet and incident on point A on the surface of the object to be measured, obtaining the ranging data L at point A on the surface of the object to be measured. A Keep the coaxial rangefinder in place, adjust the inclination of the glass sheet on the Z axis through the motor, so that the ranging laser transmitted through the glass sheet starts to move from point A on the surface of the object to be measured and incident on point B on the surface of the object to be measured, and obtain the ranging data L of point B on the surface of the object to be measured B ; Point B on the surface of the object to be measured is adjacent to point A on the surface of the object to be measured;

[0012] 2) The inclination angle of the glass sheet on the Y axis is adjusted by the motor, so that the ranging laser after passing through the glass sheet starts to move from point B on the surface of the object to be measured and incident on point C on the surface of the object to be measured, and the ranging data L at point C on the surface of the object to be measured is obtained. C ; Point C on the surface of the object to be measured is adjacent to point B on the surface of the object to be measured and point D on the surface of the object to be measured respectively;

[0013] 3) The inclination angle of the glass sheet on the Z axis is adjusted by the motor, so that the ranging laser after passing through the glass sheet starts to move from point A on the surface of the object to be measured and incident on point D on the surface of the object to be measured, and the ranging data L at point D on the surface of the object to be measured is obtained. D ; Point D on the surface of the object to be measured is adjacent to point A on the surface of the object to be measured;

[0014] 4) According to L A , LB , L C and L D The final distance measurement data is determined by the relationship between

[0015] The specific implementation of the above step 4) is:

[0016] When the ranging data L A , ranging data L B , ranging data L C And the distance data L D When any distance measurement data has a large deviation from the other three distance measurement data, the distance measurement data with the large deviation is eliminated, and the average value of the remaining three distance measurement data is taken as the final distance measurement data; the deviation is obtained by the distance meter, and the deviation is caused by the unevenness of the coating;

[0017] Preferably, when the ranging data L A , ranging data L B , ranging data L C And the distance data L D If there is a large deviation between any two adjacent distance measurement data and the remaining two distance measurement data, then after retaining the remaining two distance measurement data, repeat step 1), step 2) or step 3) to obtain the distance measurement data L of point E on the surface of the object to be measured E and the distance data L of point F on the surface of the object to be measured F According to L A , L B , L C , L D , L E and L F The final distance measurement data is determined by the relationship between

[0018] A laser processing system, characterized in that: the laser processing system comprises a laser forming component, a coated workpiece, a beam combining mirror and the laser ranging optical component as described above; the laser forming component emits a forming laser to the coated workpiece; the laser ranging optical component emits a ranging laser to the coated workpiece; the forming laser and the ranging laser are coaxial via the beam combining mirror.

[0019] The above-mentioned laser forming component includes a laser and a processing head; the laser emits a forming laser; the beam combining mirror and the processing head are arranged in sequence from front to back on the optical path of the forming laser; the forming laser is incident on the coated workpiece after passing through the processing head; the ranging laser is incident on the coated workpiece after passing through the beam combining mirror and the processing head.

[0020] The above-mentioned laser forming assembly also includes a reflector; the beam combining mirror, the reflector and the processing head are arranged in sequence from front to back on the optical path where the forming laser is located.

[0021] A laser processing method for a coated workpiece based on the laser processing system as described above, characterized in that the method comprises the following steps:

[0022] 1) Assembling the laser processing system as described above;

[0023] 2) Turning on the laser distance measurement optical component as described above, the laser distance measurement optical component emits a distance measurement laser toward the coated workpiece;

[0024] 3) Determine the processing distance of the coated workpiece by using a ranging laser;

[0025] 4) Turn off the laser distance measurement optical component as described above, turn on the laser forming component, and the laser forming component emits a forming laser toward the coated workpiece;

[0026] 5) The shaping laser performs laser processing on the coated workpiece at the processing distance obtained in step 3).

[0027] The advantages of the present invention are:

[0028] The present invention provides a laser ranging optical component and a laser processing system, wherein the laser ranging optical component includes a coaxial rangefinder and a beam translation module on the same optical path as the coaxial rangefinder. The present invention is a beam translation measurement scheme for coaxial ranging based on FMCW, which can be placed in the laser processing optical path or can be separately placed externally for measurement. The four-point method is used for testing, and the accuracy and consistency of the measurement result are judged according to the data of the four points tested. The four-point method is used for testing by high-precision testing of adjacent points near the coating, thereby avoiding the inaccuracy of the measurement accuracy. The present invention uses a laser coaxial ranging scheme, that is, the emitted light and the collected light are in the same optical path, rather than a triangulation ranging scheme. It is based on the coherent reception principle of frequency modulated continuous wave (FMCW). It can be integrated into the laser processing optical path or a separate external paraxial. The scheme will not be affected by the addition of lenses and reflectors of devices in the coaxial optical path, and can achieve the effect of ranging, especially the high-precision measurement of the processing distance of coated materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the laser ranging optical component provided by the present invention;

[0030] Figure 2 This is a schematic diagram of the principle of the laser ranging optical component provided by the present invention;

[0031] Figure 3 It is a schematic diagram of the principle of four-point forming of the laser ranging optical component provided by the present invention;

[0032] Figure 4It is a schematic diagram of the principle of optimizing four points based on the laser ranging optical component provided by the present invention;

[0033] Figure 5 It is a structural schematic diagram of the laser processing system provided by the present invention;

[0034] in:

[0035] 1-coaxial rangefinder; 2-beam translation module; 3-motor; 4-laser; 5-beam combiner; 6-reflector; 7-processing head; 8-coated workpiece. DETAILED DESCRIPTION

[0036] See also Figure 1 The present invention provides a laser ranging optical component, including a coaxial rangefinder 1 and a beam translation module 2 on the same optical path as the coaxial rangefinder 1. The beam translation module 2 includes a motor 3 and a glass sheet; the glass sheet and the coaxial rangefinder 1 are on the same optical path; the motor 3 is connected to the glass sheet and drives the glass sheet to tilt on two axes. Exemplarily, the motor 3 includes a first motor and a second motor; the first motor and the second motor are respectively connected to the glass sheet; the first motor drives the glass sheet to tilt on the Y axis; the second motor drives the glass sheet to tilt on the Z axis. Preferably, the first motor drives the glass sheet to tilt at an angle of ±30° on the Y axis; the second motor drives the glass sheet to tilt at an angle of ±30° on the Z axis.

[0037] The present invention provides a distance measurement method based on the laser distance measurement optical component as described above. A beam translation module is placed in front of the laser coaxial distance head. The beam translation module is a glass sheet. The main principle is that the light passing through it will be displaced in parallel. Figure 2 , the calculation formula is as follows:

[0038]

[0039] in:

[0040] △y is the distance of translation;

[0041] n is the refractive index of the glass sheet;

[0042] θ is the angle of rotation of the glass sheet;

[0043] t is the thickness of the glass sheet.

[0044] Therefore, based on this principle, combined with Figure 3 as well as Figure 4 The distance measurement method provided by the present invention specifically includes the following steps:

[0045] 1) The coaxial rangefinder 1 emits a ranging laser, which is incident on point A on the surface of the object to be measured after being transmitted through the glass sheet, and the ranging data L of point A on the surface of the object to be measured is obtained. A Keep the coaxial rangefinder 1 in place, adjust the inclination of the glass sheet on the Z axis through the motor 3, so that the ranging laser after passing through the glass sheet starts to move from point A on the surface of the object to be measured and incident on point B on the surface of the object to be measured, and obtain the ranging data L of point B on the surface of the object to be measured B ; Point B on the surface of the object to be measured is adjacent to point A on the surface of the object to be measured;

[0046] 2) The inclination angle of the glass sheet on the Y axis is adjusted by the motor 3, so that the ranging laser after passing through the glass sheet starts to move from point B on the surface of the object to be measured and incident on point C on the surface of the object to be measured, and the ranging data L of point C on the surface of the object to be measured is obtained. C ; Point C on the surface of the object to be measured is adjacent to point B on the surface of the object to be measured and point D on the surface of the object to be measured respectively;

[0047] 3) The inclination angle of the glass sheet on the Z axis is adjusted by the motor 3, so that the ranging laser after passing through the glass sheet starts to move from point A on the surface of the object to be measured and incident on point D on the surface of the object to be measured, and the ranging data L at point D on the surface of the object to be measured is obtained. D ; Point D on the surface of the object to be measured is adjacent to point A on the surface of the object to be measured;

[0048] 4) According to L A , L B , L C and L D The final distance measurement data is determined by the relationship between

[0049] The specific implementation of step 4) is as follows:

[0050] When the ranging data L A , ranging data L B , ranging data L C And the distance data L D When any distance measurement data has a large deviation from the other three distance measurement data, the distance measurement data with a large deviation is eliminated, and the average value of the remaining three distance measurement data is taken as the final distance measurement data; the deviation is obtained by the distance meter, and the deviation is caused by the uneven coating;

[0051] Preferably, when the ranging data L A , ranging data L B , ranging data L C And the distance data L D If there is a large deviation between any two adjacent distance measurement data and the remaining two distance measurement data, then after retaining the remaining two distance measurement data, repeat step 1), step 2) or step 3) to obtain the distance measurement data L of point E on the surface of the object to be measuredE and the distance data L of point F on the surface of the object to be measured F According to L A , L B , L C , L D , L E and L F The final distance measurement data is determined by the relationship between

[0052] See also Figure 4 , for example, when the glass is tilted on two axes by controlling the motor, the light can be moved to different adjacent points. The distance measurement scheme is to obtain the distance measurement data given by the four points ABCD through the movement of the two axes. According to the four points, if the data of one point deviates greatly from the other three points, the data is eliminated and the average value of the other three points is used as the distance measurement data. When the data of point AB differs greatly from the data of point CD, or the data of point BC differs greatly from the data of point AD, the translation is continued. For example, if the data of point AB differs greatly from the data of point CD, the point AB is translated to the left by point EF. The difference between the data of point EF and point AB is small, and the data is established. On the contrary, the point GH is translated to the right of point CD. The translation data of point CD and point GH are close, which indicates that the data of point CD is accurate, that is, the main purpose of moving point CD to the right to point GH is to make the data of the four adjacent points or the four points of the test results closer and smaller in error. The data of AB or CD is taken as the mean (the values ​​of the two points are added and averaged), and then it is positioned as the distance measurement data value. It should be noted that AB are two points, which are two data on a line segment, and can be considered as two adjacent points.

[0053] See also Figure 5 The present invention also provides a laser processing system, including a laser forming component, a coated workpiece 8, a beam combiner 5 and the laser ranging optical component as described above; the laser forming component emits a forming laser to the coated workpiece 8; the laser ranging optical component emits a ranging laser to the coated workpiece 8; the forming laser and the ranging laser are coaxial through the beam combiner 5.

[0054] Exemplarily, the laser forming assembly includes a laser 4 and a processing head 7; the laser 4 emits a forming laser; a beam combiner 5 and a processing head 7 are sequentially arranged from front to back on the optical path where the forming laser is located; the forming laser is incident on the coated workpiece 8 after passing through the processing head 7; the ranging laser is incident on the coated workpiece 8 after passing through the beam combiner 5 and the processing head 7. The laser forming assembly also includes a reflector 6; the beam combiner 5, the reflector 6 and the processing head 7 are sequentially arranged from front to back on the optical path where the forming laser is located.

[0055] Based on the aforementioned laser machining system, the present invention further provides a laser machining method for a coated workpiece, the method comprising the following steps:

[0056] 1) Assemble the laser processing system;

[0057] 2) Turning on the laser distance measuring optical component, the laser distance measuring optical component emits a distance measuring laser toward the coated workpiece 8;

[0058] 3) Determine the processing distance of the coated workpiece 8 by using a ranging laser;

[0059] 4) Turn off the laser distance measuring optical component, turn on the laser forming component, and the laser forming component emits forming laser to the coated workpiece 8;

[0060] 5) The shaping laser performs laser processing on the coated workpiece 8 at the processing distance obtained in step 3).

[0061] The present invention uses a laser coaxial ranging solution, that is, the emitted light and the collected light are in the same optical path, rather than a triangulation ranging solution. It is based on the coherent reception principle of frequency modulated continuous wave (FMCW). It can be integrated into the laser processing optical path or a separate external paraxial. This solution will not be affected by the addition of lenses and reflectors of devices in the coaxial optical path, and can achieve the ranging effect.

Claims

1. A laser ranging optical component, characterized in that: The laser distance measurement optical component comprises a coaxial distance meter (1) and a light beam translation module (2) located on the same optical path as the coaxial distance meter (1).

2. The laser ranging optical component according to claim 1, characterized in that: The light beam translation module (2) comprises a motor (3) and a glass sheet; the glass sheet and the coaxial distance meter (1) are in the same optical path; the motor (3) is connected to the glass sheet and drives the glass sheet to tilt on two axes.

3. The laser ranging optical component according to claim 2, characterized in that: The motor (3) comprises a first motor and a second motor; the first motor and the second motor are respectively connected to the glass sheet; the first motor drives the glass sheet to tilt on the Y axis; The second motor drives the glass sheet to tilt on the Z axis.

4. The laser ranging optical component according to claim 3, characterized in that: The first motor drives the glass sheet to tilt at an angle of ±30° on the Y axis; the second motor drives the glass sheet to tilt at an angle of ±30° on the Z axis.

5. A distance measurement method based on the laser distance measurement optical assembly as claimed in claim 1, 2, 3 or 4, characterized in that: The distance measurement method comprises the following steps: 1) The coaxial rangefinder (1) emits a distance measuring laser, which is incident on point A on the surface of the object to be measured after being transmitted through the glass sheet, and obtains the distance measurement data L at point A on the surface of the object to be measured. A The coaxial rangefinder (1) is kept in place, and the inclination angle of the glass sheet on the Z axis is adjusted by the motor (3), so that the ranging laser beam transmitted through the glass sheet starts to move from point A on the surface of the object to be measured and is incident on point B on the surface of the object to be measured, thereby obtaining the ranging data L of point B on the surface of the object to be measured. B ; Point B on the surface of the object to be measured is adjacent to point A on the surface of the object to be measured; 2) The inclination angle of the glass sheet on the Y axis is adjusted by the motor (3), so that the ranging laser after passing through the glass sheet starts to move horizontally from point B on the surface of the object to be measured and is incident on point C on the surface of the object to be measured, thereby obtaining the ranging data L at point C on the surface of the object to be measured. C ; Point C on the surface of the object to be measured is adjacent to point B on the surface of the object to be measured and point D on the surface of the object to be measured respectively; 3) The inclination angle of the glass sheet on the Z axis is adjusted by the motor (3), so that the ranging laser after passing through the glass sheet starts to move horizontally from point A on the surface of the object to be measured and is incident on point D on the surface of the object to be measured, thereby obtaining the ranging data L at point D on the surface of the object to be measured. D ; Point D on the surface of the object to be measured is adjacent to point A on the surface of the object to be measured; 4) According to L A , L B , L C and L D The final distance measurement data is determined by the relationship between 6. The distance measurement method according to claim 5, characterized in that: The specific implementation method of step 4) is: When the ranging data L A , ranging data L B , ranging data L C And the distance data L D When any distance measurement data has a large deviation from the other three distance measurement data, the distance measurement data with the large deviation is eliminated, and the average value of the remaining three distance measurement data is taken as the final distance measurement data; the deviation is obtained by the distance meter, and the deviation is caused by the unevenness of the coating; Preferably, when the ranging data L A , ranging data L B , ranging data L C And the distance data L D If there is a large deviation between any two adjacent distance measurement data and the remaining two distance measurement data, then after retaining the remaining two distance measurement data, repeat step 1), step 2) or step 3) to obtain the distance measurement data L of point E on the surface of the object to be measured E and the distance data L of point F on the surface of the object to be measured F According to L A , L B , L C , L D , L E and L F The final distance measurement data is determined by the relationship between 7. A laser processing system, characterized in that: The laser processing system comprises a laser forming component, a coated workpiece (8), a beam combining mirror (5), and a laser ranging optical component as described in any one of claims 1 to 4; the laser forming component emits a forming laser to the coated workpiece (8); the laser ranging optical component emits a ranging laser to the coated workpiece (8); the forming laser and the ranging laser are coaxial via the beam combining mirror (5).

8. The laser processing system according to claim 7, characterized in that: The laser forming component comprises a laser (4) and a processing head (7); the laser (4) emits forming laser; the beam combining mirror (5) and the processing head (7) are arranged in sequence from front to back on the optical path of the forming laser; the forming laser is incident on a coated workpiece (8) after passing through the processing head (7); and the distance measuring laser is incident on the coated workpiece (8) after passing through the beam combining mirror (5) and the processing head (7).

9. The laser processing system according to claim 8, characterized in that: The laser forming assembly also includes a reflector (6); the beam combining mirror (5), the reflector (6) and the processing head (7) are arranged in sequence from front to back on the optical path of the forming laser.

10. A laser processing method for a coated workpiece based on the laser processing system according to claim 7, 8 or 9, characterized in that: The method comprises the following steps: 1) Assembling the laser processing system as described in claim 7, 8 or 9; 2) turning on the laser distance measurement optical component as claimed in any one of claims 1 to 4, so that the laser distance measurement optical component emits distance measurement laser toward the coated workpiece (8); 3) determining the processing distance of the coated workpiece (8) by using a distance measuring laser; 4) turning off the laser distance measuring optical component as claimed in any one of claims 1 to 4, turning on the laser forming component, and the laser forming component emitting forming laser toward the coated workpiece (8); 5) The shaping laser performs laser processing on the coated workpiece (8) at the processing distance obtained in step 3).

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