A laser welding method for a glass tube

Abstract

The present invention discloses a laser welding method for a glass tube, which is characterized in that: three laser beams are respectively provided, and the transmission directions and focal points of the laser beams are controlled so that the focal points of the three laser beams respectively scan one-third of the annular tube wall of the glass tube to be welded and weld the tube wall. Through the combination of the scanning ranges of the three laser beams, the laser transverse welding of the entire annular tube wall of the glass tube is realized. The present invention can achieve the laser transverse welding of the glass tube without moving or rotating the glass tube, can well control the welding precision, and improve the welding efficiency.

Description

Technical Field

[0001] The present invention relates to a laser processing method, specifically to a laser welding method, which is particularly applicable to the processing of glass tubes. Background Art

[0002] During chemical, physical, and biological experiments, glass tubes are often used. Especially during experiments with various acidic and alkaline solutions, glass tubes have the advantages of high temperature resistance, corrosion resistance, and no leakage. Welding and processing glass tubes is an important process in the application of glass tubes.

[0003] In the prior art, the welding methods for glass tubes include hot air welding, flame welding, and laser welding, etc. Their basic principle of action is to heat the parts to be welded above the glass softening temperature, so that the two ends of the glass tubes to be welded are joined together to achieve welding. For this special material and shape of glass tubes, whether it is flame welding or laser welding, usually a fixed heating position is adopted, and the glass tube is rotated to complete the welding of the entire circumference of the glass tube. Due to the addition of rotating components with mechanical movement, their accuracy and efficiency are affected to a certain extent. And due to the deviation of the material itself from the ideal cylindrical shape, the welding may not be completed smoothly.

[0004] Therefore, the control deviation caused by mechanical movement is an important factor affecting the welding accuracy of glass tubes. Seeking a welding method that does not require mechanical movement control of the glass tube during welding is of great significance for improving the welding accuracy of glass tubes. Summary of the Invention

[0005] The invention objective of the present invention is to provide a laser welding method for glass tubes to improve the laser welding processing accuracy and efficiency of glass tubes and ensure the welding effect of glass tubes.

[0006] To achieve the above invention objective, the technical solution adopted by the present invention is: a laser welding method for glass tubes, providing a laser beam, using a first beam splitting device to split the laser beam into a first laser beam and an intermediate laser beam, using a second beam splitting device to split the intermediate laser beam into a second laser beam and a third laser beam, respectively adjusting the irradiation directions of the intermediate laser beam, the second laser beam, and the third laser beam through multiple reflectors, using a galvanometer scanner and a field lens to adjust the focusing position of the laser beam, so that the focusing points of the three laser beams respectively scan one-third of the annular tube wall of the glass tube to be welded and weld the tube wall, and through the combination of the scanning ranges of the three laser beams, realize the laser welding of the entire annular tube wall of the glass tube.

[0007] In the above technical solution, three laser beams are obtained through two beam splitters, and each laser beam is controlled to scan one-third of the tube wall of the glass tube respectively, thereby realizing the welding of the entire glass tube. During this process, it is not necessary to move or rotate the glass tube. Instead, three galvanometers are used to control the focusing positions of the three laser beams respectively to realize the scanning of the glass tube wall. Therefore, there is no mechanical movement of the glass tube during the welding process, ensuring the welding quality.

[0008] In a preferred technical solution, the galvanometer is a three-dimensional galvanometer. Through the control of the three-dimensional galvanometer, the focusing point of the laser beam is kept on the tube wall of the glass tube during translation.

[0009] In the above technical solution, the first beam splitting device is a first semi-transparent and semi-reflective mirror, and the transmittance of the first semi-transparent and semi-reflective mirror is set so that the power of the middle laser beam is twice the power of the first laser beam.

[0010] The second beam splitting device is a second semi-transparent and semi-reflective mirror, and the transmittance of the second semi-transparent and semi-reflective mirror is set so that the powers of the second laser beam and the third laser beam are the same.

[0011] Through the above settings, it can be ensured that the three laser beams have similar powers.

[0012] In a further technical solution, a beam monitoring camera is used to photograph the beam focusing point, confirm the position where the beam acts on the glass tube wall, and feed the position information back to the galvanometer system to accurately adjust the position of the beam action point. Generally, if the shape of the glass tube is round and has small tolerances, it is only necessary to control the galvanometer according to the set scanning path of the focusing point. However, if the shape of the glass tube has certain tolerances, feedback control can be realized by setting up a beam monitoring camera to fine-tune the scanning path to optimize the laser processing quality.

[0013] In the above technical solution, the laser beam is generated by a fiber laser, a solid laser or a carbon dioxide gas laser, and the laser beam is focused by a field lens.

[0014] The method of the present invention can be realized by a laser welding device for glass tubes. A laser welding device may be configured such that a first half-transmissive and half-reflective mirror is disposed on the output laser light path of a laser. The transmitted light of the first half-transmissive and half-reflective mirror is a first laser beam, which irradiates the glass tube to be welded. The reflected light is an intermediate laser beam. The intermediate laser beam reaches a second half-transmissive and half-reflective mirror via a first reflector. The reflected light of the second half-transmissive and half-reflective mirror is a second laser beam, which irradiates the glass tube to be welded. The angle between the second laser beam and the first laser beam is 120°. The transmitted light of the second half-transmissive and half-reflective mirror is a third laser beam. The third laser beam irradiates the glass tube to be welded after passing through a second reflector and a third reflector. The angles between the third laser beam and the first laser beam and the second laser beam are 120° respectively. Galvanometers and field lenses are respectively disposed in the light paths where the first laser beam, the second laser beam, and the third laser beam irradiate the glass tube to be welded, so that the focal points of the three laser beams respectively scan and irradiate one-third of the annular tube wall of the glass tube to be welded.

[0015] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0016] 1. The present invention utilizes two beam splitting devices to obtain three laser beams with similar powers, and changes the welding position on the glass tube wall by deflecting the laser beams. The focal points of the three laser beams respectively scan one-third of the annular tube wall of the glass tube to be welded, thereby covering the entire annular tube wall, and realizing laser welding of the glass tube without moving or rotating the glass tube.

[0017] 2. Since there is no mechanical movement or rotation of the glass tube during the welding process, the welding accuracy can be well controlled and the welding efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the optical path structure of an embodiment of the present invention.

[0019] Wherein: 1. Laser; 2. First half-transmissive and half-reflective mirror; 3. Galvanometer; 4. Field lens; 5. First reflector; 6. Second half-transmissive and half-reflective mirror; 7. Second reflector; 8. Third reflector; 9. Glass tube. EMBODIMENTS

[0020] The present invention will be further described below with reference to the drawings and embodiments:

[0021] Embodiment 1: A laser welding method for a glass tube. Provide a laser beam. Use a first beam splitting device to split the laser beam into a first laser beam and an intermediate laser beam. Use a second beam splitting device to split the intermediate laser beam into a second laser beam and a third laser beam. Adjust the irradiation directions of the intermediate laser beam, the second laser beam, and the third laser beam respectively through multiple reflectors. Use a galvanometer scanner and a field lens to adjust the focusing position of the laser beam, so that the focusing points of the three laser beams scan one-third of the annular tube wall of the glass tube to be welded and weld the glass tube wall. Through the combination of the scanning ranges of the three laser beams, realize the laser welding of the entire annular tube wall of the glass tube.

[0022] To implement the above welding method, refer to Figure 1 As shown, a laser welding device for a glass tube is provided, including a glass tube clamping mechanism (not shown in the figure) for clamping and fixing the glass tube 9 to be welded.

[0023] The laser 1 uses a green nanosecond pulsed fiber laser. A first half-transmissive and half-reflective mirror 2, a first reflector 5, a second half-transmissive and half-reflective mirror 6, a second reflector 7, and a third reflector 8 are arranged in the output optical path. The light emitted by the laser 1 is split by the first half-transmissive and half-reflective mirror 2. The transmitted light is the first laser beam, and the reflected light is the intermediate laser beam. The intermediate laser beam is reflected by the first reflector 5 and reaches the second half-transmissive and half-reflective mirror 6. The reflected light is the second laser beam, and the transmitted light is the third laser beam. The third laser beam is changed in direction by the second reflector 7 and the third reflector 8, so that the first laser beam, the second laser beam, and the third laser beam irradiate the glass tube 9 to be welded at intervals of 120°.

[0024] In the irradiation optical paths of the first laser beam, the second laser beam, and the third laser beam, a galvanometer scanner 3 and a field lens 4 are respectively arranged. The field lens focuses the laser beam, and the galvanometer scanner adjusts the focusing position of the laser beam, so that the focusing points of the three laser beams scan one-third of the annular tube wall of the glass tube to be welded and weld the glass tube wall.

[0025] To ensure the beam scanning and focusing welding effect, in this embodiment, a beam monitoring camera is provided. The beam monitoring camera photographs the beam focusing point. The output of the beam monitoring camera is connected and transmitted to the control system of the galvanometer scanner to perform feedback control on the galvanometer scanner to accurately adjust the position of the beam action point. The beam monitoring camera can be configured with a green light filter to reduce the intensity of the overly strong green laser displayed and the interference to detection.

Claims

1. A laser welding method for a glass tube, characterized in that: Provide a laser beam, divide the laser beam into a first laser beam and an intermediate laser beam by using a first beam splitting device, divide the intermediate laser beam into a second laser beam and a third laser beam by using a second beam splitting device, adjust the irradiation directions of the intermediate laser beam, the second laser beam, and the third laser beam respectively through a plurality of mirrors, and adjust the focusing position of the laser beam by using a galvanometer scanner and a field lens, so that the focusing points of the three laser beams scan one-third of the annular tube wall of the glass tube to be welded and weld the glass tube wall. Through the combination of the scanning ranges of the three laser beams, laser welding of the entire annular tube wall of the glass tube is achieved.

2. The laser welding method of the glass tube according to claim 1, characterized in that: The galvanometer scanner is a three-dimensional galvanometer scanner. Through the control of the three-dimensional galvanometer scanner, the focusing point of the laser beam is kept on the glass tube wall during translation.

3. The laser welding method of the glass tube according to claim 1, characterized in that: The first beam splitting device is a first semi-transparent and semi-reflective mirror, and the transmittance of the first semi-transparent and semi-reflective mirror is set so that the power of the intermediate laser beam is twice the power of the first laser beam.

4. The laser welding method of the glass tube according to claim 1, characterized in that: The second beam splitting device is a second semi-transparent and semi-reflective mirror, and the transmittance of the second semi-transparent and semi-reflective mirror is set so that the powers of the second laser beam and the third laser beam are the same.

5. The laser welding method of the glass tube according to claim 1, characterized in that: A beam monitoring camera is used to photograph the beam focusing point, confirm the position where the beam acts on the glass tube wall, and feed back the position information to the galvanometer scanner system to accurately adjust the position of the beam action point.

6. The laser welding method of the glass tube according to claim 1, wherein: The laser beam is generated by a fiber laser, a solid laser or a carbon dioxide gas laser, and the laser beam is focused by a field lens.

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