CN107377530A - Laser spot control system and its application, laser cleaning head - Google Patents

Abstract

The application discloses a laser focus control system. The laser focus control system includes a laser range finder, a field mirror and a calculation display unit; The surface of the workpiece is measured; the laser range finder is electrically connected to the calculation display unit, the laser range finder and the calculation display unit input the distance measurement result, and the calculation display unit outputs at least one signal . The system can monitor the defocus distance in real time. It is applied in the field of laser cleaning and can realize non-contact laser cleaning, especially in narrow spaces, and improve the quality and efficiency of cleaning. The application discloses the application of the laser focus control system and the laser cleaning head.

Description

Laser focus control system and its application, laser cleaning head

technical field

The application relates to a laser focus control system and its application, the laser focus control system and its application, and a laser cleaning head, belonging to the laser field.

Background technique

With the continuous development of science and technology, laser is continuously applied to various fields such as material processing, manufacturing and cleaning. Among them, laser cleaning technology is a green and environmentally friendly cleaning technology, which has broad application prospects in aerospace, precision machinery, hardware and other fields. . Hand-held laser cleaning equipment, with its flexible and convenient features, will become the mainstream of future laser cleaning equipment development. The handheld laser cleaning head is the core part of the equipment. Since laser cleaning uses the focus of the laser to complete the removal of stains, if the cleaning spot is too defocused, the cleaning effect will be poor. Therefore, the cleaning spot must be controlled near the focus. Since human hands will constantly float up and down during the cleaning process, and the defocus of the cleaning spot cannot be judged by the naked eye, the cleaning effect is not good, and repeated cleaning is required, resulting in waste of manpower and energy. In order to ensure that the cleaning workpiece is near the focus, the most commonly used method is to add a roller mechanism to the hand-held cleaning head. The roller moves on the surface of the workpiece to be cleaned to ensure that the focus is always on the surface of the workpiece. However, due to the impact of the rollers, this type of cleaning head cannot clean a narrow space, and the cleaning process is contact, which cannot meet the cleaning of products with special requirements.

Contents of the invention

According to one aspect of the present application, a laser focus control system is provided, which can monitor the defocus distance in real time. It is applied in the field of laser cleaning, and can realize non-contact laser cleaning, especially in narrow spaces, and improve the cleaning efficiency. quality and efficiency.

The laser focus control system includes a laser range finder, a field mirror and a calculation display unit;

The ranging laser beam emitted by the laser rangefinder is irradiated to the surface of the workpiece after passing through the field lens and measuring the distance;

The laser range finder is electrically connected to the calculation display unit, the laser range finder and the calculation display unit input the distance measurement result, and the calculation display unit outputs at least one signal.

In this application, the field lens refers to a lens that works near the focal plane of the objective lens and can effectively reduce the size of the detector, and is also called an F-Theta lens or an F-θ lens.

Preferably, the calculation and display unit outputs whether the distance measurement result is within a preset range by comparing the distance measurement result input by the laser rangefinder with preset parameters.

Preferably, the calculation and display unit determines the amount of defocus by comparing the obtained measured distance with the set distance.

Preferably, the calculation and display unit determines whether the focus position of the laser to be measured and the position of the material to be processed by the laser are appropriate by comparing the measured distance obtained with the set distance;

Preferably, the calculation and display unit displays different colors to correspond to the suitability/inappropriateness of the focus position of the laser to be measured and the position of the material to be processed by the laser.

Preferably, the calculation criterion for the calculation and display unit to judge that the focal position of the laser to be measured and the position of the material to be processed by the laser is appropriate is -ΔF≤L-(L ₁ +L ₂ +F)≤ΔF;

Wherein, L is the actual measured distance obtained in the calculation display unit;

F is the focal length of the F-Theta mirror;

ΔF is the maximum defocus allowed for laser processing;

L1 is the distance between the laser range finder and the beam emitted by the galvanometer system;

L2 is the distance between the scanning galvanometer and the F-Theta mirror.

Preferably, the values of F and ΔF are set through a calculation and display unit.

As a preferred embodiment, the distance measurement result L input by the laser rangefinder to the calculation and display unit satisfies L-(L ₀ +F)>ΔF, and the calculation and display unit outputs the first signal.

As a preferred embodiment, the distance measurement result L input by the laser rangefinder to the calculation and display unit satisfies -ΔF≤L-(L ₀ +F)≤ΔF, and the calculation and display unit outputs a second signal.

As a preferred embodiment, the distance measurement result L input by the laser rangefinder to the calculation and display unit satisfies L-(L ₀ +F)<-ΔF, and the calculation and display unit outputs a third signal.

Among them, F is the focal length of the field lens;

ΔF is the preset allowable maximum defocus amount of the laser focus control system;

L ₀ is the optical path distance between the laser range finder and the field lens.

Further preferably, the first signal, the second signal and the third signal output by the calculation and display unit are displayed differently in the form of one or more combinations of different colors, characters and patterns.

Further preferably, the laser focus control system includes a processing laser, a scanning galvanometer and a beam splitter;

The processing laser emitted by the processing laser and the ranging laser emitted by the laser range finder are coupled on the same optical path through the beam splitter, and irradiated to the surface of the workpiece through the scanning galvanometer and the field mirror in turn;

L ₀ =L ₁ +L ₂ , where L ₁ is the optical path distance between the laser rangefinder and the scanning galvanometer, and L ₂ is the optical path distance between the scanning galvanometer and the field mirror.

Preferably, the laser focus control system includes a filter, and the ranging laser emitted by the laser range finder first passes through the filter.

Preferably, the calculation and display unit includes at least one digital logic operation unit.

According to another aspect of the present application, at least one of the above-mentioned laser focus control systems is provided in at least one aspect of laser cutting, laser cleaning, laser surface roughening, laser welding, laser shock strengthening, laser cladding, and laser quenching. application. The laser focus control system provided by this application has the function of simple and fast feedback whether it is within the set distance range in laser cutting, laser cleaning, laser surface roughening, laser welding, laser shock strengthening, laser cladding, and laser quenching.

According to another aspect of the present application, a laser cleaning head is provided, including at least one of the above-mentioned laser focus control systems, the laser focus control system measures and displays whether the distance between the laser cleaning head and the surface to be cleaned is within within the preset range.

Preferably, the laser cleaning head is a hand-held non-contact laser cleaning head, and the laser cleaning head includes a cleaning laser, a laser range finder, a filter, a scanning galvanometer, a field mirror and a calculation display unit;

After the ranging laser beam emitted by the laser range finder passes through the filter, it shoots to the scanning galvanometer on the same optical path as the cleaning laser, and after being reflected by the scanning galvanometer, it irradiates the surface of the workpiece to be cleaned through the field lens and Get the ranging result L;

The distance measurement result L measured by the laser cleaning head satisfies L-(L ₁ +L ₂ +F)>ΔF, then the calculation and display unit displays a non-conforming signal and prompts the operator to move the laser cleaning head closer to the area to be cleaned. workpiece;

Alternatively, the ranging result L measured by the laser cleaning head satisfies

-ΔF≤L-(L ₁ +L ₂ +F)≤ΔF, then the calculation and display unit displays a coincidence signal, prompting the operator that laser cleaning can be performed at this distance;

Alternatively, the distance measurement result L measured by the laser cleaning head satisfies L-(L ₁ +L ₂ +F)<-ΔF, then the calculation and display unit displays a non-conforming signal and prompts the operator to replace the laser cleaning head Keep away from the workpiece to be cleaned;

Among them, F is the focal length of the field lens;

ΔF is the preset allowable maximum defocus amount of the laser focus control system;

L ₁ is the optical path distance between the laser rangefinder and the scanning galvanometer, and L ₂ is the optical path distance between the scanning galvanometer and the field mirror.

Preferably, the laser cleaning head is a core component of a handheld laser cleaning device.

As a specific implementation, the laser focus control system is applied to a manual cleaning head, including:

(1) The ranging laser and the processing laser are coupled on the same optical path through the beam splitter, and reach the surface of the workpiece to be cleaned under the action of the scanning galvanometer and the F-Theta mirror;

(2) The laser rangefinder has a pre-filter to filter out the interference light of other bands to ensure the accuracy of the laser rangefinder;

(3) The distance data obtained by the laser rangefinder is transmitted to the calculation and display unit. The calculation and display unit calculates according to the comparison between the measured distance and the set distance to determine whether the workpiece to be cleaned is within the cleanable range. If it is within the cleanable range, the green light On; if it is not within the washable range, the red light is on; among them, the calculation criterion for the calculation and display unit green light is: -ΔF≤L-(L ₁ +L ₂ +F)≤ΔF;

Among them, L is the actual measured distance;

F is the focal length of the F-Theta mirror;

ΔF is the allowable maximum defocus amount for laser cleaning;

L1 is the distance between the laser range finder and the beam emitted by the galvanometer system;

L2 is the distance between the scanning galvanometer and the F-Theta mirror;

The red light of the calculation and display unit is on, indicating that the laser head is too far away from the workpiece, that is, L-(L ₁ +L ₂ +F)>ΔF; or that the laser head is too close to the workpiece, that is, L-(L ₁ +L ₂ + F)<-ΔF.

The ΔF is obtained through the actual quality inspection and comparative measurement of laser cleaning; if the F-Theta mirror is replaced, both F and ΔF will change, and ΔF needs to be further re-measured;

The calculation and display unit can be a simple digital logic operation unit, through which the values of ΔF and F can be set.

The workpiece to be cleaned is selected from one of metal materials (such as stainless steel, carbon steel, aluminum alloys, superalloys, titanium alloys, etc.), non-metallic materials (such as glass, ceramics, plastics, composite materials, fabrics, wood, etc.) .

The beneficial effect that this application can produce comprises:

1) The laser focus control system provided by this application overcomes the defect in the prior art that "the defocus of the cleaning spot cannot be judged by the naked eye, resulting in poor cleaning effect, requiring repeated cleaning, resulting in waste of manpower and energy" .

2) The laser focus control system provided by this application can monitor the defocus distance in real time, and it can be used for hand-held cleaning heads, which can realize non-contact high-quality laser cleaning, especially in narrow spaces, and improve the quality and efficiency of cleaning .

3) The laser focus control system provided by this application can monitor the defocus amount in real time, which can be used in laser processing to improve the quality and efficiency of laser processing.

4) The laser focus control system provided by this application is applied to laser cleaning/processing, and has the advantages of safety and environmental protection, simple operation, convenient implementation, and low cost.

Description of drawings

FIG. 1 is a schematic diagram of a laser focus control system involved in this application.

Reference signs:

20-laser rangefinder; 22-filter; 24-computing display unit;

40-beam splitter; 42-scanning mirror; 44-field mirror

6-workpiece to be processed; 8-working laser.

detailed description

The present application is described in detail below in conjunction with the examples, but the present application is not limited to these examples.

Unless otherwise specified, the raw materials and components in the examples of the present application are all purchased through commercial channels.

The model of the handheld laser cleaning device is IIILaserClean-50, and the manufacturer is Ningbo Dayai Laser Technology Co., Ltd.

Embodiment 1 laser cleaning

The laser focus control system in the present embodiment is as described in Fig. 1, comprises: comprise laser rangefinder 20, filter 22, computing display unit 24, spectroscope 40, scanning vibrating mirror 42, field lens 44, working laser 8 . In this embodiment, the working laser 8 is a cleaning laser.

Specifically, the ranging laser beam emitted by the laser rangefinder 20 passes through the filter 22, passes through the beam splitter 40 and shoots to the scanning galvanometer 42 on the same optical path as the working laser 8 reflected by the beam splitter 40, and the scanning galvanometer 42 After reflection, it passes through the field lens 44 to irradiate the surface of the workpiece 6 to be processed and measure the distance to obtain the distance measurement result L. In this embodiment, the workpiece 6 to be processed is the workpiece to be cleaned.

Wherein, the calculation and display unit 24 is a digital logic operation unit.

In this embodiment, a hand-held laser cleaning device is used to clean the paint on the surface of the magnesium-aluminum alloy; the cleaning head of the hand-held laser cleaning device adopts the above-mentioned laser focus control system, and the specific working mode is as follows:

(1) Turn on the laser and the hand-held laser cleaning device that emits the ranging laser, then couple the ranging laser and the cleaning laser 8 on an optical path through the beam splitter 40, and reach the workpiece 6 to be cleaned through the scanning vibrating mirror 42 and the field mirror 44 s surface;

Among them, the laser that generates the cleaning laser is a nanosecond laser with a wavelength of 1064nm;

(2) The range-finding laser emitted by the laser range finder 20 first passes through a filter 22, which is used to filter out interfering light in other bands to ensure the accuracy of laser range-finding;

(3) The distance data L obtained by the laser rangefinder 20 is transmitted to the calculation and display unit 24, and the calculation and display unit 24 determines whether the workpiece 6 to be cleaned is within the cleanable range according to the comparison calculation between the measurement distance L and the set distance, if in In the washable range, the green light is on; if it is not in the washable range, the red light is on and prompts whether to stay away or approach; among them, the calculation criterion for the calculation and display unit green light is: -ΔF≤L-(L ₁ +L ₂ + F)≤ΔF;

Among them, L is the actual measured distance;

F is the focal length of the field lens;

ΔF is the allowable maximum defocus amount for laser cleaning;

L ₁ is the distance between the laser rangefinder and the beam emitted by the galvanometer system;

L ₂ is the distance between the scanning galvanometer and the F-Theta mirror.

Specifically:

When -ΔF≤L-(L ₁ +L ₂ +F)≤ΔF, the calculation and display unit 24 lights up in green, indicating that the distance between the laser head and the workpiece is within the working range, and laser cleaning can be performed;

When L-(L ₁ +L ₂ +F)>ΔF, the red light of the calculation display unit 24 is on and displayed as a descending arrow, indicating that the laser head is too far away from the workpiece and should be approached;

When L-(L ₁ +L ₂ +F)<-ΔF, the red light of the calculation display unit 24 is on and displayed as a rising arrow, indicating that the laser head is too close to the workpiece and should be kept away;

The ΔF is obtained through actual quality inspection and comparative measurement of laser cleaning;

The values of ΔF and F are set through the calculation and display unit;

That is, when the operator holds the laser cleaning head for cleaning operations, if the calculation display unit 24 green light is on, the laser cleaning is performed directly; if the calculation display unit 24 red light is on, move the position of the hand-held laser cleaning head according to the prompt or adjust At the position of the material to be cleaned, the green light of the calculation and display unit is on, and then laser cleaning is performed.

Embodiment 2 laser cleaning

Use a handheld laser cleaning device to clean the rusty carbon steel material, replace the field lens 44, and reset ΔF according to the focal length F of the new field lens 44 and the material to be cleaned.

The cleaning head of the handheld laser cleaning device adopts a laser focus control system, the schematic diagram of which is shown in FIG.

Embodiment 3 laser texture

The laser focus control system in the present embodiment is as described in Fig. 1, comprises: comprise laser range finder 20, filter 22, computing display unit 24, spectroscope 40, scanning vibrating mirror 42, field mirror 44, working laser 8 . In this embodiment, the working laser 8 is a processing laser.

Specifically, the ranging laser beam emitted by the laser rangefinder 20 passes through the filter 22, passes through the beam splitter 40 and shoots to the scanning galvanometer 42 on the same optical path as the working laser 8 reflected by the beam splitter 40, and the scanning galvanometer 42 After reflection, it passes through the field lens 44 to irradiate the surface of the workpiece 6 to be processed and measure the distance to obtain the distance measurement result L. In this embodiment, the workpiece 6 to be processed is the material to be processed.

Wherein, the calculation and display unit 24 is a digital logic operation unit.

A laser processing device is used to roughen the surface of the mold steel material; the laser scanning head of the laser processing device adopts the above-mentioned laser focus control system, and the specific working mode is as follows.

(1) Turn on the laser device and the laser processing device that emit the ranging laser, then the ranging laser and the processing laser 8 are coupled on an optical path by the beam splitter 40, and reach the material 6 to be processed through the scanning vibrating mirror 42 and the field mirror 44 surface;

Wherein, the laser for generating the processing laser is a nanosecond pulse laser with a power of 50W and a wavelength of 532nm.

(2) The range-finding laser emitted by the laser range finder 20 first passes through a filter 22, which is used to filter out interfering light in other bands to ensure the accuracy of laser range-finding;

(3) The distance data L obtained by the laser range finder 20 is transmitted to the calculation and display unit 24, and the calculation and display unit 24 determines whether the material to be processed 6 is at a distance where effective laser processing can be performed according to the comparison calculation between the measurement distance L and the set distance Within the range, if it is within the effective range of laser processing, the green light is on; if it is not within the effective range of laser processing, the red light is on and prompts whether to stay away or approach; among them, the calculation criterion for the green light of the calculation display unit is: -ΔF≤L-(L ₁ +L ₂ +F)≤ΔF;

Among them, L is the actual measured distance;

F is the focal length of the field lens;

ΔF is the allowable maximum defocus amount for laser cleaning;

L ₁ is the distance between the laser range finder and the beam emitted by the galvanometer system;

L ₂ is the distance between the scanning galvanometer and the F-Theta mirror.

Specifically:

When -ΔF≤L-(L ₁ +L ₂ +F)≤ΔF, the calculation and display unit 24 lights up green, indicating that the distance between the laser head and the workpiece is within the working range, and laser processing can be performed;

When L-(L ₁ +L ₂ +F)>ΔF, the red light of the calculation display unit 24 is on and displayed as a descending arrow, indicating that the laser head is too far away from the workpiece and should be approached;

When L-(L ₁ +L ₂ +F)<-ΔF, the red light of the calculation display unit 24 is on and displayed as a rising arrow, indicating that the laser head is too close to the workpiece and should be kept away;

The ΔF is obtained through actual quality inspection and comparative measurement of laser cleaning;

The values of ΔF and F are set through the calculation and display unit;

That is, when the operator carries out the laser processing operation with the laser processing head in hand, if the calculation and display unit 24 has a green light on, the laser processing will be performed directly; Adjust the position of the material to be cleaned until the green light of the calculation and display unit is on, and then laser processing is performed.

The above are only a few embodiments of the application, and do not limit the application in any form. Although the application is disclosed as above with preferred embodiments, it is not intended to limit the application. Any skilled person familiar with this field, Without departing from the scope of the technical solution of the present application, any changes or modifications made using the technical content disclosed above are equivalent to equivalent implementation cases, and all belong to the scope of the technical solution.

Claims (10)

1. A laser focus control system, characterized in that, the laser focus control system comprises a laser range finder, a field mirror and a computing display unit; The ranging laser beam emitted by the laser rangefinder is irradiated to the surface of the workpiece after passing through the field lens and measuring the distance; The laser range finder is electrically connected to the calculation display unit, the laser range finder and the calculation display unit input the distance measurement result, and the calculation display unit outputs at least one signal. 2. The laser focus control system according to claim 1, wherein the calculation and display unit outputs whether the distance measurement result is within the preset range by comparing the distance measurement result input by the laser rangefinder with preset parameters. within range. 3. The laser focus control system according to claim 1, wherein the distance measurement result L input by the laser range finder to the calculation and display unit satisfies L-(L ₀ +F)>ΔF, the calculation and display unit outputs the first signal; Alternatively, the distance measurement result L input by the laser range finder to the calculation and display unit satisfies -ΔF≤L-(L ₀ +F)≤ΔF, the calculation and display unit outputs a second signal; Alternatively, the distance measurement result L input by the laser range finder to the calculation and display unit satisfies L-(L ₀ +F)<-ΔF, the calculation and display unit outputs a third signal; Among them, F is the focal length of the field lens; ΔF is the preset allowable maximum defocus amount of the laser focus control system; L ₀ is the optical path distance between the laser range finder and the field lens. 4. The laser focus control system according to claim 3, characterized in that, the first signal, the second signal and the third signal output by the calculation and display unit are displayed in different colors, characters, patterns or Various combinations are displayed differently. 5. The laser focus control system according to claim 3, wherein the laser focus control system comprises a processing laser, a scanning vibrating mirror and a beam splitter; The processing laser emitted by the processing laser and the ranging laser emitted by the laser range finder are coupled on the same optical path through the beam splitter, and irradiated to the surface of the workpiece through the scanning galvanometer and the field mirror in turn; L ₀ =L ₁ +L ₂ , where L ₁ is the optical path distance between the laser range finder and the scanning galvanometer, and L ₂ is the optical path distance between the scanning galvanometer and the field mirror. 6. The laser focus control system according to claim 1, characterized in that the laser focus control system comprises a filter, and the ranging laser light emitted by the laser range finder first passes through the filter. 7. The laser focus control system according to claim 1, wherein the calculation and display unit comprises at least one digital logic operation unit. 8. At least one of the laser focus control systems according to any one of claims 1 to 7, in laser cutting, laser cleaning, laser surface roughening, laser welding, laser shock strengthening, laser cladding, laser quenching at least One aspect of application. 9. A laser cleaning head, characterized in that it comprises at least one of the laser focus control systems according to any one of claims 1 to 7, the laser focus control system measures and displays the laser cleaning head and the laser focus control system to be cleaned Whether the distance of the surface is within the preset range. 10. The laser cleaning head according to claim 9, characterized in that, the laser cleaning head is a hand-held non-contact laser cleaning head, and the laser cleaning head includes a cleaning laser, a laser range finder, a filter, a scanning vibrator mirror, field mirror and computing display unit; After the ranging laser beam emitted by the laser range finder passes through the filter, it shoots to the scanning galvanometer on the same optical path as the cleaning laser, and after being reflected by the scanning galvanometer, it irradiates the surface of the workpiece to be cleaned through the field lens and Get the ranging result L; The distance measurement result L measured by the laser cleaning head satisfies L-(L ₁ +L ₂ +F)>ΔF, then the calculation and display unit displays a non-conforming signal and prompts the operator to move the laser cleaning head closer to the area to be cleaned. workpiece; Alternatively, the ranging result L measured by the laser cleaning head satisfies -ΔF≤L-(L ₁ +L ₂ +F)≤ΔF, then the calculation and display unit displays a coincidence signal, prompting the operator that laser cleaning can be performed at this distance; Alternatively, the distance measurement result L measured by the laser cleaning head satisfies L-(L ₁ +L ₂ +F)<-ΔF, then the calculation and display unit displays a non-conforming signal and prompts the operator to replace the laser cleaning head Keep away from the workpiece to be cleaned; Among them, F is the focal length of the field lens; ΔF is the preset allowable maximum defocus amount of the laser focus control system; L ₁ is the optical path distance between the laser rangefinder and the scanning galvanometer, and L ₂ is the optical path distance between the scanning galvanometer and the field mirror.