Method for adjusting confocal surface of laser processing system and coaxial vision system

Abstract

The application relates to a confocal surface adjustment method of a laser processing system and a coaxial vision system, and the method comprises the following steps: turning on a laser, adjusting the position of a workpiece so that a focused light spot after a focusing mirror acts on the surface of the workpiece, and recording the position of the workpiece at the moment; turning on an illumination light source, and adjusting the position of the workpiece so that the image definition on a CCD camera display interface meets preset conditions; adjusting the position and angle of the CCD camera and an imaging lens, and observing the vision center of the CCD camera display interface in real time; when the illumination light beam and the laser beam passing through a dichroic mirror are displayed on the vision center of the CCD camera display interface, the adjustment is stopped; adjusting the position of the workpiece to the position in step 1; adjusting a beam expander so that the illumination light is in a diverging or converging state; and observing the display image of the illumination light reflected to the CCD camera display interface through the surface of the workpiece in real time until the image definition meets the preset conditions. The adjustment method is simple, efficient and high in precision.

Description

TECHNICAL FIELD

[0001] The present application relates to a confocal surface adjustment method, in particular to a confocal surface adjustment method of a laser processing system and a coaxial vision system. BACKGROUND

[0002] At present, in the laser processing system, the coaxial vision system has been widely used in the positioning before part processing, the online monitoring in the processing process and the like. The coupling principle between the laser processing system and the coaxial vision system is that the laser beam is focused to the part surface through the optical elements such as the laser focusing mirror / field mirror, and then the reflected light of the part is imaged to the CCD camera, so as to obtain the position, angle, shape and the like of the part.

[0003] In the engineering application of the coaxial vision system, due to the chromatic aberration (uncorrected chromatic aberration focusing system) or the beam divergence angle between the vision illumination light and the laser processing light path, the vision imaging plane and the laser focal plane do not coincide, thereby leading to low laser processing precision. Therefore, in order to realize the high coincidence of the focal planes of the laser processing system and the coaxial vision system, the focal planes of the laser processing system and the coaxial vision system need to be accurately adjusted. The existing adjustment method usually adopts the beam splitter or other optical elements to couple the laser light source and the CCD camera on the same optical axis to image the object, and the focal plane of the laser focusing mirror and the imaging plane of the CCD camera are overlapped by adjusting the focusing mechanism.

[0004] However, the existing adjustment method has the following disadvantages: a precise mechanical device needs to be designed to accurately adjust the processing focal plane and the vision imaging plane, the focusing mechanism is complex, the precision requirement is high, and the alignment precision is limited by the focusing mechanism. SUMMARY

[0005] The purpose of the present application is to solve the technical problems of the existing adjustment method, i.e. the need to design a precise mechanical device to accurately adjust the processing focal plane and the vision imaging plane, the complexity of the focusing mechanism, the high precision requirement, and the limitation of the alignment precision by the focusing mechanism, and to provide a confocal surface adjustment method of a laser processing system and a coaxial vision system.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0007] A confocal surface adjustment method of a laser processing system and a coaxial vision system, which is suitable for the case that the vision imaging plane is in front of the laser focal plane, and the laser processing system and the coaxial vision system comprise a laser, a dichroic mirror and a focusing mirror which are arranged in sequence along the laser emission direction, a beam expander, an imaging lens and a CCD camera which are arranged in sequence along the light path reflected by the dichroic mirror, and an illumination light source arranged on one side of the imaging lens.

[0008] The special feature is that it comprises the following steps:

[0009] Step 1, turn on the laser, adjust the position of the workpiece so that the focusing spot after the focusing lens acts on its surface, and record the position of the workpiece at this time, denoted as X;

[0010] Step 2, turn on the illumination light source, and adjust the position of the workpiece so that the image clarity on the display interface of the CCD camera meets the preset condition;

[0011] Step 3, adjust the position and angle of the CCD camera and the imaging lens, and observe the visual center of the display interface of the CCD camera in real time, and stop adjusting when the illumination light beam passing through the dichroic mirror and the laser beam are both displayed in the visual center of the display interface of the CCD camera;

[0012] Step 4, adjust the position of the workpiece to the X position in step 1;

[0013] Step 5, adjust the beam expander so that the illumination light is in a divergent state; and observe the display image of the illumination light reflected from the surface of the workpiece to the display interface of the CCD camera in real time until the image clarity meets the preset condition, complete the calibration and adjustment of the laser focal plane and the visual imaging plane, that is, complete the confocal plane adjustment of the laser processing system and the coaxial vision system.

[0014] Further, in step 5, the interval between the two lenses in the beam expander is reduced to make the illumination light divergent.

[0015] Meanwhile, the application also provides a confocal plane adjustment method of a laser processing system and a coaxial vision system, which is suitable for the case that the visual imaging plane is behind the laser focal plane, and the laser processing system and the coaxial vision system comprise a laser, a dichroic mirror and a focusing lens arranged in sequence along the emission direction of the laser, a beam expander, an imaging lens and a CCD camera arranged in sequence along the reflected light path of the dichroic mirror, and an illumination light source arranged on one side of the imaging lens.

[0016] The special feature is that it comprises the following steps:

[0017] Step 1, turn on the laser, adjust the position of the workpiece so that the focusing spot after the focusing lens acts on its surface, and record the position of the workpiece at this time, denoted as X;

[0018] Step 2, turn on the illumination light source, and adjust the position of the workpiece so that the image clarity on the display interface of the CCD camera meets the preset condition;

[0019] Step 3, adjust the position and angle of the CCD camera and the imaging lens, and observe the visual center of the display interface of the CCD camera in real time, and stop adjusting when the illumination light beam passing through the dichroic mirror and the laser beam are both displayed in the visual center of the display interface of the CCD camera;

[0020] Step 4, adjust the position of the workpiece to the X position in step 1;

[0021] Step 5, adjust the beam expander so that the illumination light is in a converging state; real-time observation of the display image of the reflected illumination light on the workpiece surface to the CCD camera until the image clarity meets the preset condition to complete the calibration adjustment of the laser focal plane and the visual imaging plane, that is, the confocal surface adjustment of the laser processing system and the coaxial vision system.

[0022] Further, in step 5, the illumination light is in a converging state by increasing the spacing between the two lenses in the beam expander.

[0023] Compared with the prior art, the beneficial effects of the present application are:

[0024] The present application realizes online adjustment of the divergence angle of the coaxial vision system illumination light path, realizes online adjustment of the CCD camera imaging plane, and thus realizes precise coincidence of the imaging plane and the processing focal plane, provides an effective means for the confocal surface of the coaxial vision system light path, and breaks the dependence of the existing adjustment method on the high-precision focusing mechanism. The adjustment method is simple, efficient and high-precision. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a structural schematic diagram of the prior art laser processing system and coaxial vision system;

[0026] Figure 2 is a state schematic diagram of the first embodiment of the present application.

[0027] In the figure: 1-laser, 2-dichroic mirror, 3-focusing mirror, 4-workpiece, 5-beam expander, 6-imaging lens, 7-CCD camera, 8-illumination light source. DETAILED DESCRIPTION

[0028] In order to make the purpose, advantages and characteristics of the present application clearer, the following will further describe a laser processing system and coaxial vision system confocal surface adjustment method according to the present application in combination with the drawings and specific embodiments. The advantages and characteristics of the present application will be clearer according to the following specific embodiments. It should be noted that: the drawings are very simplified and use non-precise proportions, only to facilitate and clarify the purpose of assisting the description of the embodiments of the present application; secondly, the structure shown in the drawings is often a part of the actual structure.

[0029] Reference Figure 1The existing laser processing system and coaxial vision system include a laser 1, a dichroic mirror 2, a focusing mirror 3, a beam expander 5, an imaging lens 6, a CCD camera 7 and an illumination light source 8. The laser 1 emits laser light with a wavelength of 1064 nm. The dichroic mirror 2 is arranged on the light path of the laser 1. The focusing mirror 3 is arranged on the transmission light path of the dichroic mirror 2, and the focal length of the focusing mirror 3 is 20 mm. The beam expander 5 is arranged on the reflection light path of the dichroic mirror 2. The workpiece 4 to be processed is arranged on the light path of the focusing mirror 3. The imaging lens 6 is arranged on the light path of the beam expander 5, and the working distance of the imaging lens 6 is 110 mm. The illumination light source 8 is arranged on the refraction light path of the imaging lens 6, and the wavelength of the illumination light source 8 is 515 nm. The CCD camera 7 is arranged on the transmission light path of the imaging lens 6. The light reflected by the workpiece 4 sequentially passes through the focusing mirror 3, the dichroic mirror 2, the beam expander 5 and the imaging lens 6 to the CCD camera 7.

[0030] In use, first, the illumination light source 8 is turned on so that the illumination light beam sequentially passes through the imaging lens 6, the beam expander 5, the dichroic mirror 2 and the focusing mirror 3 to the surface of the workpiece 4. The reflected light on the surface of the workpiece 4 sequentially passes through the focusing mirror 3, the dichroic mirror 2, the beam expander 5 and the imaging lens 6 to the CCD camera 7. After the CCD camera 7 acquires the relevant information of the workpiece 4, the laser 1 is started. The laser emitted by the laser 1 sequentially passes through the dichroic mirror 2 and the focusing mirror 3 to the surface of the workpiece 4. According to the acquired relevant information, the workpiece 4 is processed.

[0031] In actual use, in order to ensure good processing quality, the visual imaging surface of the coaxial vision system and the laser focal surface need to be accurately overlapped. In order to realize the accurate overlap of the visual imaging surface and the laser focal surface, the application provides two adjustment methods, which are respectively suitable for two different situations.

[0032] Embodiment one

[0033] The embodiment provides a confocal surface adjustment method of a laser processing system and a coaxial vision system, which is suitable for the case that the visual imaging surface is before the laser focal plane, and the method is as follows: Figure 2 , and the method comprises the following steps:

[0034] Step 1, the laser 1 is started, the position of the workpiece 4 is adjusted so that the focused light spot after the focusing mirror 3 acts on the surface thereof, and the position of the workpiece 4 at this time is recorded as X;

[0035] Step 2, the illumination light source 8 is turned on, and the position of the workpiece 4 is adjusted so that the image clarity on the display interface of the CCD camera 7 meets the preset condition;

[0036] Step 3, adjust the position and angle of the CCD camera 7 and the imaging lens 6, and observe the visual center of the display interface of the CCD camera 7 in real time. When the illumination light and the laser beam passing through the dichroic mirror 2 are both displayed in the visual center of the display interface of the CCD camera 7, stop adjusting;

[0037] Step 4, adjust the position of the workpiece 4 to the X position in step 1;

[0038] Step 5, by reducing the interval between the two lenses in the beam expander 5, the illumination light is in a divergent state; and observe the display image of the reflected illumination light on the surface of the workpiece 4 to the display interface of the CCD camera 7 in real time until the image clarity meets the preset condition, complete the calibration adjustment of the laser focal plane and the visual imaging plane, that is, complete the confocal surface adjustment of the laser processing system and the coaxial vision system.

[0039] Example Two

[0040] The embodiment provides a confocal surface adjustment method of a laser processing system and a coaxial vision system, which is suitable for the case that the visual imaging plane is behind the laser focal plane, and different from the embodiment one is that in step 5, the embodiment increases the interval between the two lenses in the beam expander 5, so that the illumination light is in a convergent state, and observes the display image of the reflected illumination light on the surface of the workpiece 4 to the display interface of the CCD camera 7 in real time until the image clarity meets the preset condition, completes the calibration adjustment of the visual imaging plane and the laser focal plane. The other steps of the embodiment are the same as those of the embodiment one.

Claims

1. A method for adjusting the cofocal plane of a laser processing system and a coaxial vision system, applicable to the case where the visual imaging plane is in front of the laser focal plane, wherein the laser processing system and the coaxial vision system include a laser (1), a dichroic mirror (2) and a focusing mirror (3) arranged sequentially along the emission direction of the laser (1), a beam expander (5), an imaging lens (6), a CCD camera (7) arranged sequentially along the reflection path of the dichroic mirror (2), and an illumination source (8) arranged on one side of the imaging lens (6); Its features are, Includes the following steps: Step 1: Turn on the laser (1), adjust the position of the workpiece (4) so ​​that the focused spot after passing through the focusing lens (3) acts on its surface, and record the position of the workpiece (4) at this time as X; Step 2: Turn on the lighting source (8) and adjust the position of the workpiece (4) so ​​that the image clarity on the CCD camera (7) display interface meets the preset conditions; Step 3: Adjust the position and angle of the CCD camera (7) and the imaging lens (6), and observe the visual center of the CCD camera (7) display interface in real time. When the illumination beam and laser beam passing through the dichroic mirror (2) are both displayed at the visual center of the CCD camera (7) display interface, stop adjusting. Step 4: Adjust the position of workpiece (4) to the X position in step 1; Step 5: Adjust the beam expander (5) to make the illumination light diverge; and observe in real time the image of the illumination light reflected from the surface of the workpiece (4) to the display interface of the CCD camera (7) until the image clarity meets the preset conditions, and complete the calibration and adjustment of the laser focal plane and the visual imaging plane, that is, complete the cofocal plane adjustment of the laser processing system and the coaxial vision system.

2. The method for adjusting the confocal surface of the laser processing system and the coaxial vision system according to claim 1, characterized in that: In step 5, the illumination light is made to diverge by reducing the gap between the two lenses in the beam expander (5).

3. A method for adjusting the cofocal surface of a laser processing system and a coaxial vision system, applicable to situations where the visual imaging surface is behind the laser focal plane, wherein the laser processing system and the coaxial vision system include a laser (1), a dichroic mirror (2) and a focusing mirror (3) arranged sequentially along the emission direction of the laser (1), a beam expander (5), an imaging lens (6), a CCD camera (7) arranged sequentially along the reflection path of the dichroic mirror (2), and an illumination source (8) arranged on one side of the imaging lens (6); Its features are, Includes the following steps: Step 1: Turn on the laser (1), adjust the position of the workpiece (4) so ​​that the focused spot after passing through the focusing lens (3) acts on its surface, and record the position of the workpiece (4) at this time as X; Step 2: Turn on the lighting source (8) and adjust the position of the workpiece (4) so ​​that the image clarity on the CCD camera (7) display interface meets the preset conditions; Step 3: Adjust the position and angle of the CCD camera (7) and the imaging lens (6), and observe the visual center of the CCD camera (7) display interface in real time. When the illumination beam and laser beam passing through the dichroic mirror (2) are both displayed at the visual center of the CCD camera (7) display interface, stop adjusting. Step 4: Adjust the position of workpiece (4) to the X position in step 1; Step 5: Adjust the beam expander (5) to make the illumination light constricted; observe the image of the illumination light reflected from the surface of the workpiece (4) to the CCD camera (7) in real time until the image clarity meets the preset conditions, and complete the calibration and adjustment of the laser focal plane and the visual imaging plane, that is, complete the cofocal plane adjustment of the laser processing system and the coaxial vision system.

4. The method for adjusting the confocal surface of the laser processing system and the coaxial vision system according to claim 3, characterized in that: In step 5, the illumination light is contracted by increasing the gap between the two lenses in the beam expander (5).

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