Laser welding gun
By using temperature sensors and controllers in laser welding guns to analyze the surface temperature distribution and increase speed of the lens, the problem of pollutants blocking the laser beam is solved, and the welding quality and safety are improved.
Patent Information
- Application Number
- CN202420688551.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-03
- Publication Date
- 2025-07-22
- Estimated Expiration
- 2034-04-03
AI Technical Summary
During laser welding, pollutants such as welding slag and smoke adhere to the protective lens, blocking the laser beam's exit path and reducing the welding quality.
At least one temperature sensor is used to locate outside the laser beam exit area to obtain the temperature distribution of the protective lens surface, and to analyze the temperature distribution and the increase speed by the controller to detect and identify contaminants.
The detection of contaminants on the protective lens is achieved, the welding quality is improved, and the risks during the welding process are reduced.
Smart Images
Figure CN223129608U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of laser welding, and in particular to a laser welding gun. Background Art
[0002] Laser welding guns are often used to weld battery shells during battery manufacturing. Laser welding is prone to produce spattering welding slag and smoke. These pollutants adhere to or burn the protective lens of the welding gun, block the exit path of the laser beam, and thus reduce the welding quality.
[0003] Therefore, how to detect contaminants on protective lenses is a technical problem that needs to be solved urgently. Utility Model Content
[0004] In view of the above problems, the present application provides a laser welding gun to detect contaminants on a protective lens of the laser welding gun.
[0005] The present application provides a laser welding gun, which includes: a light source for emitting a laser beam; a protective lens for preventing contaminants from entering the interior of the laser welding gun; at least one temperature sensor is located outside the laser beam exit area to prevent blocking the optical path of the laser beam exit, and at least one temperature sensor is used to obtain the temperature distribution on the surface of the protective lens; and a controller is used to detect contaminants on the protective lens based on the temperature distribution.
[0006] Since the protective lens has a high transmittance to the laser beam, the uncontaminated protective lens basically does not absorb the laser beam energy, the temperature is low and the temperature change is not large. However, pollutants such as welding slag and smoke are usually colored and have a relatively low transmittance, which will block the emission of the laser beam and absorb the laser beam energy to increase the temperature. Therefore, the present application can determine whether there are pollutants on the surface of the protective lens based on the temperature distribution on the lens surface.
[0007] In some embodiments, the controller is specifically configured to: determine that contaminants exist on the surface of the protective lens if the temperature distribution indicates that there is an area on the surface of the protective lens with a temperature greater than or equal to a temperature threshold.
[0008] Since the uncontaminated protective lens basically does not absorb the laser beam energy, the temperature of the uncontaminated area of the lens will be stable in a lower temperature range. However, the contaminated area of the lens absorbs more laser beam energy, and its temperature will rise to a higher temperature range. Therefore, if there is an area on the surface of the protective lens with a temperature greater than or equal to the temperature threshold, the present application can determine that there is contaminant on the surface of the protective lens.
[0009] In some embodiments, the controller is further configured to: calculate the temperature rise rate based on the temperature distribution information; if the temperature rise rate is greater than the maximum value of the speed range, determine that the pollutant is welding slag; or, if the temperature rise rate is within the speed range, determine that the pollutant is a burn mark; or, if the temperature rise rate is less than the minimum value of the speed range, determine that the pollutant is a fingerprint or oil stain.
[0010] It can be understood that after determining that there are pollutants on the surface of the protective lens, the temperature rise rate of the pollutants can be calculated by detecting the temperature change of the pollutants over a period of time. For pollutants such as welding slag that are colored and have a relatively dark color, they absorb more laser beam energy and have a very fast temperature rise rate; for pollutants such as burn marks that are damaged on the surface of the lens, the tiny interfaces formed by the damage will reflect the laser beam and absorb part of the energy of the laser beam, resulting in a relatively fast temperature rise rate; for relatively transparent pollutants such as fingerprints and oil stains, they absorb less laser beam energy and have a slower temperature rise rate. Therefore, the controller can judge the type of pollutants on the surface of the protective lens according to the temperature rise rate.
[0011] In some embodiments, the temperature sensor includes a thermal imager or an infrared sensor. It can be understood that both the thermal imager and the infrared sensor can be used in various non-contact temperature measurement scenarios to avoid blocking the normal outgoing path of the laser beam. Both of them detect the infrared radiation of the object and convert the obtained radiation parameters into temperature readings.
[0012] In some embodiments, the laser welding torch further includes a connecting member: one side of the connecting member is detachably connected to at least one temperature sensor, and the other side of the connecting member is detachably connected to the laser welding torch. It can be understood that according to different production requirements, the shapes of the welding torches used may be different, and the installation positions of the corresponding temperature sensors will also change. In this application, the detachable connection can improve the utilization rate of the temperature sensor and facilitate the installation of the protective lens. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, in all the drawings, the same reference numerals are used to represent the same components. In the drawings:
[0014] Figure 1a is a schematic structural diagram of a laser welding torch;
[0015] Figure 1b is a schematic structural diagram of a laser welding torch in an embodiment of the present application;
[0016] Figure 2 is a schematic diagram of the temperature distribution in some embodiments of the present application;
[0017] Figure 3 This is a schematic structural diagram of a laser welding torch according to some other embodiments of the present application. Detailed implementation manners
[0018] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and thus are only examples and cannot be used to limit the protection scope of the present application.
[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.
[0020] In the description of the embodiments of this application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of this application, "a plurality of" means two or more, unless otherwise specifically defined.
[0021] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase does not necessarily refer to the same embodiment everywhere in the specification, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.
[0022] In the description of the embodiments of this application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.
[0023] In the description of the embodiments of this application, the term "a plurality of" refers to two or more (including two). Similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).
[0024] To facilitate understanding of the solutions in this application, the background technology will be explained first below:
[0025] A laser welding torch is a device that uses a laser beam for welding. As shown in Figure 1, a laser welding torch generally includes a light source 101, a cavity 102, a first swing galvanometer 1031, a second swing galvanometer 1032, a focusing lens 104, a protective lens 105, and a controller 106:
[0026] The light source 101, located at one end of the cavity 102, is used to emit a laser beam A; the light source 101 here is a light-emitting device, including but not limited to semiconductor lasers, fiber lasers, and gas lasers. The laser beam A refers to a light beam formed by the radiation of particles excited by the light source 101.
[0027] The cavity 102 is used to connect the light source 101 and accommodate the first swing galvanometer 1031, the second swing galvanometer 1032, the focusing lens 104, and the protective lens 105;
[0028] The first swing galvanometer 1031 and the second swing galvanometer 1032, located inside the cavity 102, are used to change their own swing frequency and swing angle under the control of the controller 106 to adjust the emission frequency and emission trajectory of the laser beam A, so that the laser beam A irradiates on the focusing lens 104;
[0029] The focusing lens 104, located inside the cavity 102, is used to focus the laser beam A on the target material B and melt the target material B at a high temperature, thereby achieving welding.
[0030] The protective lens 105 is clamped at the other end of the cavity 102. The inner surface of the protective lens 105 contacts the internal environment of the cavity 102, and the outer surface of the protective lens 105 contacts the external environment of the laser welding torch, and is used to prevent pollutants from entering the inside of the laser welding torch (inside the cavity 102).
[0031] It should be noted that during the welding process, the splashed welding slag and soot are at a high temperature and usually have corrosiveness. Therefore, the protective lens 105 in this application can be a circular lens made of a high-temperature and corrosion-resistant metal oxide to block pollutants from entering the inside of the cavity 102 and protect the devices inside the cavity 102.
[0032] The pollutants in this application refer to substances that reduce the use effect of the laser welding torch, such as corrosive substances and substances that reduce the optical performance of the lens, including large-particle pollutants such as welding slag, small-particle pollutants such as soot, surface cracks of the lens such as burn marks and scratches, and fingerprints and oil stains, etc.
[0033] A controller 106 is used to control the laser beam A output by the light source 101, control the swinging of the first swinging galvanometer 1031 and the second swinging galvanometer 1032, and control the focal length of the focusing lens 104. The controller 106 can be a programmable logic device, discrete gate or transistor logic device integrated in the laser welding gun, or a computer device independent of the laser welding gun.
[0034] Laser welding guns are widely used in the battery manufacturing field due to their advantages such as concentrated energy, high welding precision, and small heat-affected zone, for example, in the welding of battery casings. However, there are a large amount of dust and splashing welding slag in the laser welding environment, and these pollutants will adhere to the surface of the protective lens of the laser welding gun, which will block the normal outgoing path of the laser welding and reduce the welding quality. Batteries or battery packs with poor welding quality have insufficient local strength, and there are risks such as abnormal sampling signals, power outages, and even liquid leakage and fire.
[0035] Therefore, how to detect the pollutants on the protective lens is a technical problem that needs to be solved urgently at present.
[0036] Based on the above technical problems, the present application provides a laser welding gun for detecting pollutants on the protective lens of the laser welding gun. As Figure 1b shown, in addition to including the Figure 1a light source 101 and the protective lens 105 in
[0037] the present application, the laser welding gun further includes: Figure 1b At least one temperature sensor (shown as temperature sensors 1071 to 1074 in FIG. 1), located outside the laser beam A emission area (
[0038] shown in shadow in
[0039] ), for obtaining the temperature distribution on the surface of the protective lens 105.
[0040] The emission area in the present application refers to the set of optical paths that the laser beam A may form after passing through the protective lens 105. Since the temperature sensor in the present application is located outside the laser beam A emission area, the temperature sensor can avoid blocking the normal outgoing path of the laser beam A while detecting the temperature distribution. The surface of the protective lens 105 refers to the outer surface of the protective lens 105 that contacts the external environment of the laser welding gun. Figure 2The temperature distribution diagram shows that there are areas with a temperature of 30°C, areas with a temperature of 60°C, and areas with a temperature of 80°C on the surface of the protective lens 105.
[0041] A controller 106 is configured to detect contaminants on the protective lens 105 based on the temperature distribution.
[0042] Since the protective lens 105 has a high transmittance for the laser beam A, the non - contaminated areas on the surface of the protective lens 105 basically do not absorb the energy of the laser beam A, and the temperature is relatively low and the temperature change is small. However, contaminants such as welding slag and soot are usually colored and have a relatively low light transmittance, and will absorb the energy of the laser beam A and heat up. Therefore, the controller 106 can detect whether there are contaminants on the surface of the protective lens 105 in real - time according to the temperature distribution on the lens surface.
[0043] The following will be described in detail with reference to embodiments. Figure 1b how the controller 106 in [the relevant context] detects contaminants on the protective lens 105:
[0044] In some embodiments, the controller 106 is specifically configured to: if the temperature distribution indicates that there is an area on the surface of the protective lens 105 where the temperature is greater than or equal to the temperature threshold, it is determined that there are contaminants on the surface of the protective lens.
[0045] It should be noted that the temperature threshold in this application can be the outer surface temperature of the non - contaminated protective lens 105 during the welding process.
[0046] Referring to FIG. 1, since the lens itself basically does not absorb the energy of the laser beam A, the temperature of the non - contaminated area of the lens will be stable within a relatively low temperature range. However, the contaminants on the lens absorb more energy of the laser beam A, and their temperature will rise to a relatively high temperature range. Therefore, if there is an area on the surface of the protective lens 105 where the temperature is greater than or equal to the temperature threshold, the controller 106 can determine that there are contaminants on the surface of the protective lens 105.
[0047] Exemplarily, the temperature threshold is 50°C. During the laser welding process, Figure 2 the shown temperature distribution diagram shows that there are areas with a temperature of 60°C and 80°C on the surface of the protective lens 105, then the controller 106 determines that there are contaminants on the surface of the protective lens 105.
[0048] In some embodiments, the controller 106 is specifically configured to: if the temperature distribution indicates that there is an area on the surface of the protective lens 105 where the temperature is greater than or equal to the temperature threshold, and the area of the area where the temperature is greater than or equal to the temperature threshold is greater than the area threshold, it is determined that there are contaminants on the surface of the protective lens 105.
[0049] It should be noted that the area threshold can be set according to the area of contaminants that seriously affect the outgoing light path of the laser beam A during the welding process.
[0050] Exemplarily, the temperature threshold is 50°C and the area threshold is 2 square centimeters. During the laser welding process, Figure 2 the shown temperature distribution map shows that the area of the region with a temperature of 80°C is 1 square centimeter, the area of the region with a temperature of 60°C is 0.5 square centimeter, and the temperature of the remaining regions is 50°C. Then, the controller 106 determines that there is no contaminant on the surface of the protective lens 105.
[0051] However, if Figure 2 the shown temperature distribution map shows that the area of the region with a temperature of 80°C is 2 square centimeters, the area of the region with a temperature of 60°C is 0.5 square centimeter, and the temperature of the remaining regions is 50°C. Then, the controller 106 determines that there is a contaminant on the surface of the protective lens 105.
[0052] In addition to the above function of detecting whether there is a contaminant on the surface of the protective lens 105, Figure 1b the shown controller 106 also has other functions, which will be described in detail below in combination with embodiments:
[0053] In some embodiments, the controller 106 is further configured to: calculate the temperature rise rate based on the temperature distribution information.
[0054] Exemplarily, after the controller determines that there is a contaminant on the surface of the protective lens, the temperature rise rate of the contaminant is calculated by detecting the temperature change of the contaminant over a period of time. For example, within 1 s, the temperature of the contaminant rises from 60°C to 61°C. Then, the controller calculates that the temperature rise rate of the contaminant is 1°C / s.
[0055] Furthermore, the controller 106 is further configured to: if the temperature rise rate is greater than the maximum value of the speed range, determine that the contaminant is welding slag; or
[0056] if the temperature rise rate is within the speed range, determine that the contaminant is a heat mark; or
[0057] if the temperature rise rate is less than the minimum value of the speed range, determine that the contaminant is a fingerprint or oil stain.
[0058] Contaminants such as welding slag, which are colored and have a relatively dark color, absorb more energy of the laser beam A and have a very fast temperature rise rate; heat marks such as damage will form many tiny interfaces on the lens surface, which refract, reflect the laser beam A, and absorb part of the energy of the laser beam A, resulting in a relatively fast temperature rise rate; contaminants such as fingerprints and oil stains, which are relatively transparent, absorb less energy of the laser beam A and have a slower temperature rise rate. Therefore, the controller can judge the type of contaminant on the surface of the protective lens according to the temperature rise rate.
[0059] Exemplarily, the speed range is [0.2°C / s, 0.5°C / s]. Combining Figure 1b, If the temperature rising speed of the contaminant is 1 °C / s, the controller determines that the contaminant is welding slag; if the temperature rising speed of the contaminant is 0.3 °C / s, the controller 106 determines that the contaminant is a burn mark; if the temperature rising speed of the contaminant is 0.1 °C / s, the controller 106 determines that the contaminant is a fingerprint or oil stain.
[0060] The installation method of the temperature sensor can be flexibly set, which will be described below in conjunction with embodiments:
[0061] In some embodiments, on the basis of Figure 1b as shown in Figure 3 , the laser welding torch further includes a connecting member 301: one side of the connecting member 301 is detachably connected to at least one temperature sensor, and the other side of the connecting member is detachably connected to the laser welding torch.
[0062] Here, the connecting member 301 is a corrosion-resistant and high-temperature-resistant device for fixing and supporting the temperature sensor. For example, referring to Figure 3 , the connecting member 301 is a conical columnar bracket made of ceramic material or graphite material. The end with the smallest circumference of the circular cross-section of the conical columnar bracket is detachably connected to the outer wall of the cavity 102 by means of locking or buckling; the end with the largest circumference of the circular cross-section of the conical columnar bracket is detachably connected to each temperature sensor through four universal shafts respectively. The universal shaft is also called a universal joint or a universal coupling, which is a rotatable mechanical connection device. The universal shaft can adjust the detection angle of the temperature sensor through its own rotation, so as to make the temperature sensor adapt to more temperature detection requirements.
[0063] It can be understood that in order to avoid blocking the output optical path of the laser beam A, the temperature sensor does not contact the protective lens 105. Therefore, a connecting member is needed to fix and support the temperature sensor to achieve non-contact temperature detection.
[0064] Due to different production requirements, the structure of the welding torch cavity 102 may be different. Correspondingly, the installation position of the temperature sensor also needs to be changed to avoid blocking the light output. In this application, the detachable connection of the connecting member 301 can improve the utilization rate of the temperature sensor. In addition, since the protective lens 105 needs to be frequently replaced during the production process, the detachable connecting member is convenient for replacing the protective lens.
[0065] In summary, this application discloses a laser welding torch, which includes a light source for emitting a laser beam; a protective lens for preventing contaminants from entering the interior of the laser welding torch; at least one temperature sensor located outside the laser beam emission area for obtaining the temperature distribution on the surface of the protective lens; and a controller for detecting contaminants on the protective lens based on the temperature distribution.
[0066] Since pollutants are usually colored and have a relatively low light transmittance, they will block the emission of the laser beam and absorb the energy of the laser beam to increase in temperature. Therefore, the controller can determine whether there are pollutants on the surface of the protective lens based on the temperature distribution on the lens surface; further, different pollutants have different temperature increase rates, so the controller can also determine the type of pollutants on the surface of the protective lens based on the temperature increase rate.
Claims
1. A laser welding torch, characterized in that, The laser welding torch includes: a light source for emitting a laser beam; a protective lens for preventing contaminants from entering the interior of the laser welding torch; at least one temperature sensor located outside the laser beam exit area for obtaining the temperature distribution on the surface of the protective lens; a controller for performing contaminant detection on the protective lens based on the temperature distribution.
2. The laser welding torch according to claim 1, wherein, Specifically, the controller is configured to: if the temperature distribution indicates that there is a region on the surface of the protective lens where the temperature is greater than or equal to a temperature threshold, determine that there are contaminants on the surface of the protective lens.
3. The laser welding torch according to claim 1 or 2, characterized in that, The controller is further configured to: calculate the temperature increase rate based on the temperature distribution; if the temperature increase rate is greater than the maximum value of the speed range, determine that the contaminant is welding slag; or if the temperature increase rate is within the speed range, determine that the contaminant is a burn mark; or if the temperature increase rate is less than the minimum value of the speed range, determine that the contaminant is a fingerprint or oil stain.
4. The laser welding torch according to claim 1, wherein, The temperature sensor includes a thermal imager or an infrared sensor.
5. The laser welding torch according to claim 1, characterized in that, The laser welding torch further includes a connecting member: one side of the connecting member is detachably connected to the at least one temperature sensor, and the other side of the connecting member is detachably connected to the laser welding torch.