CN111408835A - Rapid alignment method and alignment system for laser focal plane and machining datum - Google Patents

Abstract

The present invention provides a fast alignment method and alignment system between a laser focal plane and a machining datum, and solves the problems that the existing laser focus determination method has low precision and is not suitable for the actual laser machining process. The system includes a laser processing unit, a coaxial visual observation unit and an alignment substrate; the laser processing unit includes a laser, a laser rotation module and a focusing mirror arranged in sequence; the laser rotation module is used to increase the effect of laser damage; the coaxial visual observation unit includes The image acquisition camera and the lens barrel lens, and the center of the field of view of the coaxial visual observation unit coincides with the axis of the laser processing head, and its focal plane can be automatically adjusted; the alignment substrate is set on the laser processing surface, and the coaxial visual observation unit The focal plane coincides with the upper surface of the alignment substrate. The system is simple in structure and low in cost, can quickly and accurately locate the spatial position of the laser focus, and can quickly realize different processing benchmarks for the same workpiece and rapid determination of processing benchmarks for different workpieces.

Description

A fast alignment method and alignment system for laser focal plane and machining datum

technical field

The invention relates to the field of laser processing, in particular to a fast alignment method and alignment system for a laser focal plane and a machining reference.

Background technique

Laser processing technology has the advantages of no contact stress, high processing accuracy, easy to achieve automatic control, etc. It is more and more widely used in thin-walled parts, fine microstructure processing, etc. However, because the laser focus has a certain depth of focus, its positioning accuracy has a greater impact on the laser processing effect.

Chinese invention patent "CN201510205630.7" discloses a method for automatically acquiring laser focus. In this method, N processing graphics are first formed at X/Y/Z coordinates; then X/Y/Z motion is controlled by a software control system The control system and the camera vision system acquire N processing graphics, and use image algorithms to analyze the line width values of the N processing graphics; finally, compare the line width values between the processing graphics with different Z-axis coordinates and the processing of the same Z-axis coordinate The line width value of the graphic and the difference of the line width value can determine the laser focus of the laser device. Since the laser has a certain depth of focus, this method can roughly obtain the position of the laser focus, and the obtained laser focus position has low precision.

Chinese invention patent "CN201610670751.3" discloses a focus position determination device, method and device in laser processing. The method is relatively complicated, and the judgment method is not based on the actual laser processing beam, which cannot accurately reflect the actual laser focus position. , so the measurement accuracy of the laser focus is limited, and because the method and device are relatively complex, it is not suitable for the actual laser processing process.

In the actual multi-station processing, since the laser focus is not a solid point, the reference point needs to be searched many times, especially on complex curved surfaces, its reference coordinates are difficult to calculate, which greatly reduces the accuracy and efficiency of laser processing. High-precision laser focus and efficient alignment of machining datums.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problems that the existing laser focus determination method has low precision and is not suitable for the actual laser processing process, and provides a rapid alignment method and alignment system between the laser focus plane and the machining reference.

In order to achieve the above object, the present invention is achieved through the following technical solutions.

A method for quickly aligning a laser focal plane and a machining datum, comprising the following steps:

Step 1. A coaxial visual observation unit is arranged in the laser processing system, and the center of the field of view of the coaxial visual observation unit coincides with the axis of the laser processing head, and the coaxial visual observation unit includes an image acquisition camera and a lens barrel lens;

Step 2, place an alignment substrate on the laser processing surface;

Step 3: Adjust the position of the lens barrel lens so that the focal plane of the coaxial visual observation unit coincides with the upper surface of the alignment substrate;

Step 4, the laser works, emits a laser beam, the laser beam passes through the laser rotation module to increase the laser damage effect, and forms laser damage spots on the alignment substrate through the focusing mirror;

Step 5: Reduce the laser power of the laser to reduce the focal depth range that can achieve damage to the base material, until the effective focal depth of the laser damage spot is reduced to the micron level;

Step 6: Adjust the position of the focusing mirror until clear laser damage spots can be observed on the substrate, and the laser focus alignment is completed, and the positions of the focusing mirror and the alignment substrate are fixed;

Step 7: The coaxial visual observation unit observes the alignment substrate to determine whether the laser damage spots on the alignment substrate are observed with a clear imaging surface; if not, adjust the position of the lens barrel lens again until the coaxial visual observation unit Identify the laser damage spots on the alignment substrate with a clear imaging plane; at this time, the laser focal plane, the upper surface of the alignment substrate and the focal plane of the coaxial visual observation unit coincide;

Step 8. During laser processing, the focal plane of the coaxial visual observation unit obtained in step 7 is used to determine the laser focal plane of the next laser processing, so as to ensure that the reference planes of multiple processing are consistent.

At the same time, the present invention also provides a rapid alignment system for laser focal plane and machining reference, including a laser machining unit, a coaxial visual observation unit and an alignment substrate; the laser machining unit includes a laser, a laser rotating module and a focusing mirror; the laser rotation module is used to increase the laser damage effect, and the position of the focusing mirror can be adjusted; the coaxial visual observation unit includes an image acquisition camera and a lens barrel lens, and the coaxial visual observation unit The center of the field of view of the laser processing head coincides with the axis of the laser processing head, and its focal plane can be adjusted automatically; the alignment substrate is arranged on the laser processing surface, and the focal plane of the coaxial visual observation unit coincides with the upper surface of the alignment substrate.

Further, the upper surface of the alignment substrate is plated with a 20-60 micron copper film.

Further, the focusing mirror is fixedly arranged on the machine tool shaft, and the position of the focusing mirror is adjusted through the machine tool shaft.

Further, the image acquisition camera is a CCD camera.

Compared with the prior art, the present invention has the following technical effects:

1. The fast alignment system for laser focal plane and machining datum of the present invention is simple in structure and low in cost, can quickly and accurately locate the spatial position of the laser focal point, and can quickly realize different machining datums for the same workpiece through the coaxial visual observation unit. The rapid determination of the workpiece machining datum is very suitable for the accurate and rapid search of the laser focus and workpiece machining datum in the micro-hole laser processing equipment.

2. In the actual processing process, on the basis of locating the laser focal position (machine tool coordinates), the focal plane of the coaxial visual observation unit is adjusted to coincide with the laser focal plane. Then, by controlling the movement of the machine tool axis, the workpiece datum plane of the subsequent processing can be coincident with the focal plane of the coaxial visual observation unit, which can realize the high-efficiency and high-precision datum alignment of multi-station, workpiece and curved surface parts.

3. The fast aligning method of the laser focal plane and the processing datum of the present invention In the process of accurately finding the laser focus, by placing a aligning substrate coated with a copper film of tens of microns thick at the laser focal point, the surface of the aligning substrate is close to Mirror surface for easy observation of laser damage spots in the coaxial vision observation unit.

4. In the method for quickly aligning the laser focal plane and the processing datum of the present invention, since the laser rotation module can increase the laser damage effect, the focal depth range that can achieve damage to the base material can be greatly reduced by lowering the laser power, which can At the same time, the center of the field of view of the coaxial visual observation unit coincides with the axis of the micro-hole laser processing head, and its focal plane can be continuously and accurately adjusted automatically, and its focal depth is extremely narrow, which can achieve high-precision laser focus detection. allow.

Description of drawings

FIG. 1 is a schematic diagram of the rapid alignment system for the laser focal plane and the machining datum according to the present invention.

Reference signs: 1-laser; 2-laser rotation module; 3-image acquisition camera; 4-tube lens; 5-coaxial visual observation unit; 6-reflector; 7-machine axis; 8-focusing mirror; 9 -Find the substrate; 10- Industrial computer.

Detailed ways

The content of the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

The invention provides a fast alignment method and alignment system between a laser focal plane and a machining datum, which are used to realize the fast and accurate alignment of the laser focus and the fast alignment of the workpiece reference in the laser micro-hole machining equipment. The system overlaps the focal plane of the laser and the focal plane of the coaxial visual observation unit. During actual laser processing, the focal plane of the coaxial visual observation unit is used to determine the laser focal plane of the next laser processing, so that the reference planes of multiple processing are consistent. , to ensure that the processing effect of multiple processing is consistent.

As shown in FIG. 1 , the rapid alignment system for the laser focal plane and the machining datum of the present invention includes a laser machining unit, a coaxial visual observation unit 5 and an alignment substrate 9; the laser machining unit includes a laser 1, a laser rotating Module 2 and focusing mirror 8, since the laser rotation module 2 can increase the laser damage effect, the laser beam can quickly form laser damage spots on the alignment substrate 9; the focusing mirror 8 is fixedly arranged on the machine tool shaft 7, Adjust the position of the focusing mirror 8. Of course, a plurality of mirrors 6 may be provided on the laser processing optical path to adjust the laser processing optical path.

The coaxial visual observation unit 5 includes an image acquisition camera 3 and a lens barrel lens 4, and the center of the field of view of the coaxial visual observation unit 5 coincides with the axis of the laser processing head, its focal plane can be continuously and accurately adjusted automatically, and its focal depth is extremely high. narrow. The image acquisition camera 3 can be a CCD camera, and can be connected with the industrial computer 10 to realize image acquisition.

The alignment substrate 9 is arranged on the laser processing surface, so that the focal plane of the coaxial visual observation unit 5 coincides with the upper surface of the alignment substrate 9, the alignment substrate plane is parallel to the XY plane, and its surface is close to the mirror surface, and the alignment substrate 9 is aligned. The surface of the laser beam is plated with a 20-60 (specifically 50) micron thick copper film, which facilitates the observation of laser damage spots in the coaxial visual observation unit 5, which is used to find the laser focus.

At the same time, the present invention also provides a method for quickly aligning the laser focal plane and the machining datum, comprising the following steps:

Step 1. Set up a coaxial visual observation unit 5 in the laser processing system, and the center of the field of view of the coaxial visual observation unit 5 coincides with the axis of the micro-hole laser processing head. The coaxial visual observation unit 5 includes an image acquisition camera 3 and a mirror. The barrel lens 4, its focal plane can be continuously and accurately adjusted automatically, and the focal depth is extremely narrow, about 20 microns;

Step 2. Place an alignment substrate 9 above the laser processing surface. The alignment substrate 9 is a substrate coated with a 20-60 micron thick copper film. The alignment substrate plane is parallel to the XY plane, and its surface is close to a mirror surface. The roughness is about Ra0.8, which is convenient to observe the laser damage spots in the coaxial visual observation unit 5, which is used to find the laser focus;

Step 3, adjusting the position of the lens barrel lens 4, so that the focal plane of the coaxial visual observation unit 5 coincides with the upper surface of the alignment substrate 9;

Step 4: The laser 1 works, emits a laser beam, and the laser beam passes through the laser rotation module 2 to increase the laser damage effect, and forms laser damage spots on the alignment substrate 9 through the focusing mirror 8;

Step 5, greatly reducing the laser power of the laser 1, reducing the focal depth range that can achieve damage to the base material, until the effective focal depth of the laser damage spot is reduced to a micron level;

Since the laser rotation module can increase the effect of laser damage, turn on the laser rotation module 2, and reduce the laser power to about 0.05W, which greatly reduces the depth of focus range that can achieve damage to the base material, which can be reduced to micron level;

Step 6: Fine-tune the position of the focusing mirror 8 through the machine tool axis 7 until the clear laser damage spots can be observed on the base plate 9, then the laser focus alignment is completed, and the search accuracy of the laser focus is controlled below 0.2mm. At this time, Keep the position of the machine tool axis 7 and the alignment base plate 9 unchanged;

Step 7. The coaxial visual observation unit 5 observes the alignment substrate 9 to determine whether the laser damage spots on the alignment substrate 9 are observed with the clearest imaging plane; if not, adjust the position of the lens barrel lens 4 again until The coaxial visual observation unit 5 identifies the laser damage spot on the alignment substrate 9 with the clearest imaging plane; at this time, the laser focal plane, the upper surface of the alignment substrate 9 and the focal plane of the coaxial visual observation unit 5 coincide;

Step 8. For workpieces with multiple batches or multiple processing surfaces, during laser processing, the position of the laser focus can be quickly determined by the focal plane of the coaxial visual observation unit 5, so as to realize the benchmark high precision during multi-station and curved surface processing. Looking for, to ensure the consistency of the processing effect of multiple processing.

In the method of the present invention, a coaxial visual observation unit 5 is added to the micro-hole processing equipment, and during the precise searching process of the laser focus, a targeting substrate 9 coated with a copper film with a thickness of several tens of microns is placed at the laser focus; The laser damage effect can be increased, and the focal depth range that can achieve damage to the base material can be reduced by greatly reducing the laser power, which can be reduced to the level of microns; by adjusting the position of the focusing mirror 8, the precise laser focus can be found. allow. In the actual processing process, on the basis of locating the laser focus position (machine tool coordinates), adjust the focal plane of the coaxial visual observation unit to coincide with the laser focal plane, and then control the movement of the machine tool axis to make the workpiece benchmark for subsequent processing. The plane coincides with the focal plane of the coaxial visual observation unit to achieve high-efficiency and high-precision benchmarking of multi-station, workpiece and curved parts.

The device required by the method of the invention has a simple structure and low cost, can quickly and accurately locate the spatial position of the laser focus, and can quickly determine the different machining datums of the same workpiece and the machining datums of different workpieces through the coaxial visual observation unit, which is very suitable for The laser focus and workpiece processing datum in the micro-hole laser processing equipment are accurately and quickly searched.

Claims (8)

1. a fast aligning method of laser focal plane and machining datum, is characterized in that, comprises the following steps: Step 1. A coaxial visual observation unit is arranged in the laser processing system, and the center of the field of view of the coaxial visual observation unit coincides with the axis of the laser processing head, and the coaxial visual observation unit includes an image acquisition camera and a lens barrel lens; Step 2, place an alignment substrate on the laser processing surface; Step 3: Adjust the position of the lens barrel lens so that the focal plane of the coaxial visual observation unit coincides with the upper surface of the alignment substrate; Step 4, the laser works, emits a laser beam, the laser beam passes through the laser rotation module to increase the laser damage effect, and forms laser damage spots on the alignment substrate through the focusing mirror; Step 5: Reduce the laser power of the laser until the effective focal depth of the laser damage spot is reduced to the micron level; Step 6: Adjust the position of the focusing mirror until clear laser damage spots can be observed on the substrate, and the laser focus alignment is completed, and the positions of the focusing mirror and the alignment substrate are fixed; Step 7. The coaxial visual observation unit observes the alignment substrate to determine whether laser damage spots are observed with a clear imaging surface; if not, adjust the position of the lens barrel again until the coaxial visual observation unit has a clear imaging surface. Laser damage spots are identified; at this time, the focal plane of the laser, the upper surface of the alignment substrate and the focal plane of the coaxial visual observation unit coincide; Step 8. During laser processing, the focal plane of the coaxial visual observation unit obtained in step 7 is used to determine the laser focal plane of the next laser processing, so as to ensure that the reference planes of multiple processing are consistent. 2 . The method for quickly aligning a laser focal plane and a machining reference according to claim 1 , wherein in step 2, the upper surface of the alignment substrate is plated with a 20-60 micron copper film. 3 . 3. The method for quickly aligning the laser focal plane and the machining reference according to claim 1 or 2, wherein in step 6, the position of the focusing mirror is adjusted by the machine tool axis. 4 . The method for quickly aligning a laser focal plane and a machining datum according to claim 3 , wherein in step 1, the image acquisition camera is a CCD camera. 5 . 5. A rapid alignment system for laser focal plane and machining datum, characterized in that: it comprises a laser machining unit, a coaxial visual observation unit (5) and an alignment substrate (9); The laser processing unit comprises a laser (1), a laser rotation module (2) and a focusing mirror (8) arranged in sequence along the optical path; the laser rotation module (2) is used to increase the laser damage effect, and the focusing mirror ( 8) The position can be adjusted; The coaxial visual observation unit (5) includes an image acquisition camera (3) and a lens barrel lens (4), and the center of the field of view of the coaxial visual observation unit (5) coincides with the axis of the laser processing head, and its focal plane can Automatic adjustment; The alignment substrate (9) is arranged on the laser processing surface, and the focal plane of the coaxial visual observation unit (5) coincides with the upper surface of the alignment substrate (9). 6 . The rapid alignment system for laser focal plane and machining reference according to claim 5 , wherein the top surface of the alignment substrate ( 9 ) is plated with a 20-60 micron copper film. 7 . 7. The fast aligning system for laser focal plane and machining reference according to claim 5 or 6, characterized in that: the focusing mirror (8) is fixedly arranged on the machine tool shaft (7), and is adjusted by the machine tool shaft (7) The position of the focusing mirror (8). 8 . The fast alignment system for laser focal plane and machining reference according to claim 7 , wherein the image acquisition camera ( 3 ) is a CCD camera. 9 .

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