CN114101908B

CN114101908B - All-position laser welding system and welding method

Info

Publication number: CN114101908B
Application number: CN202111661900.7A
Authority: CN
Inventors: 陈锦涛; 黄举近; 吕航; 陈辉; 郑森木; 裴利程
Original assignee: Southwest Jiaotong University
Current assignee: Southwest Jiaotong University
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2022-07-15
Anticipated expiration: 2041-12-31
Also published as: CN114101908A

Abstract

The invention belongs to the technical field of laser welding, and particularly relates to an all-position laser welding system and a welding method, which comprises a control system connected with a laser welding head, a tool platform for bearing a welding part and a laser emitter for providing energy for welding for the laser welding head; the incident end is installed on a rotating part of the rotating disk. By disposing the incident end on the rotating part of the rotating disk; the laser welding head can be driven by the rotating disk, when the laser beam is emitted, the laser beam which can be emitted by the laser welding head can rotate +/-450 degrees around the rotating shaft of the rotating disk, and the all-position butt welding of the thin-walled pipe with the diameter of 5-12mm is realized; the rotating disc is arranged on the moving assembly which can drive the laser welding head to do linear motion on an x axis, a y axis and a z axis of a three-dimensional coordinate system, so that the moving assembly can adjust the position of the laser welding head, and the rotating axis of the laser welding head can be in the same line with the axis of a pipeline to be welded.

Description

All-position laser welding system and welding method

Technical Field

The invention belongs to the technical field of laser welding, and particularly relates to an all-position laser welding system and an all-position laser welding method.

Background

With the development of the industries such as aerospace, nuclear power, pipelines and the like in China, the all-position welding technology is more and more widely applied. The laser self-fluxing welding technology is also gradually becoming widely popularized and industrially applied as a high-energy beam welding method; compared with the traditional welding technologies such as manual shielded metal arc welding and gas metal arc welding, the laser welding has the advantages of small welding heat input, high welding speed, small welding seam deformation and the like, can further optimize the welding process flow, is favorable for further popularizing the application of the laser welding technology in all-position welding, and realizes the change of a new process and a new method.

Through searching and finding Chinese patent with publication number CN109514086B, an all-position laser welding process method for a continuous pipe is provided, the butt welding process for the petroleum continuous pipe is optimized, but the welding process provided by the method is only suitable for welding parts with large diameters and pipe wall thicknesses; high-temperature alloy pipelines used for conveying dye or exhausting in aerospace and nuclear power are generally small in diameter and thin in pipe wall, and the welding of the pipelines with small diameters and thin pipe walls is difficult to achieve by adopting the laser welding process.

Disclosure of Invention

The invention aims to provide an all-position laser welding system and a welding method, which are used for realizing all-position butt welding of thin-walled tubes with the diameter within 12mm and realizing popularization and application of a new process method.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a full-position laser welding system comprises a control system connected with a laser welding head, a tool platform for bearing a welding part and a laser emitter for providing energy for welding for the laser welding head; the laser welding head comprises a first incident pipe, and one end of the first incident pipe is connected with an incident end connected with the laser transmitter through an optical fiber; the other end of the first incident tube is vertically connected with one end of a second incident tube, and the other end of the second incident tube is vertically connected with a third incident tube;

an air knife with an emitting end facing the tool platform is installed at one end, away from the second incident tube, of the third incident tube, and a first reflector capable of reflecting laser to the air knife and adjusting the angle is installed at the position where the third incident tube and the second incident tube are intersected;

a second reflecting mirror for reflecting laser to the first reflecting mirror is arranged at the position where the second incident pipe intersects with the first incident pipe;

a third reflector for reflecting laser to the second reflector is arranged at one end of the first incident pipe close to the incident end;

a focusing part is arranged in the second incidence pipe;

the incident end is installed on a rotating part of the rotating disk.

The invention designs the mechanism of the laser welding head and installs each reflector; the laser welding head can be driven by the rotating disc, when laser beams are emitted, the laser beams which can be emitted by the laser welding head can rotate +/-450 degrees around a rotating shaft of the rotating disc, and therefore all-position butt welding of thin-walled tubes with the diameters of 5-12mm is achieved; in addition, the invention can realize the adjustment of the focal length and the incident light angle by adjusting the angle of the first reflector, thereby avoiding the use unicity of the device.

Furthermore, the fixed part of the rotating disk is arranged on a moving component which drives the laser welding head to do linear back and forth movement on the x axis, the y axis and the z axis of the three-dimensional coordinate system; the rotating disc and the moving assembly are electrically connected with a controller.

According to the invention, the moving assembly is arranged, so that the laser welding head can linearly move back and forth on the x axis, the y axis and the z axis of the three-dimensional coordinate system, and the position of the laser welding head can be adjusted through the moving assembly, so that the rotation axis of the laser welding head and the axis of the pipeline to be welded can be in the same line.

Preferably, the control system comprises a control host, a display end electrically connected with the control host, a controller electrically connected with the control host, and a water cooling machine respectively connected with the laser emitter and the laser welding head through a water cooling pipe;

the control host is electrically connected with the laser transmitter.

Preferably, the angle of the first reflector is adjusted based on an angle adjusting assembly, the angle adjusting assembly comprises a square end cover mounted on the outer wall of the tube body at the intersection position of the second incident tube and the third incident tube, a bolt is mounted at each of four corners of the end cover, the bolts penetrate through the end cover and the outer wall of the tube body and extend into the tube at the intersection position of the second incident tube and the third incident tube, and the bolts are in threaded fit with through holes in the end cover;

the ends of the two bolts close to the second incident tube are arranged on the first reflector in a hinged mode; and the end heads of the two bolts close to the third incident tube are rotatably provided with sleeves, and the sleeves and the first reflector are assembled in a hinged mode.

According to the invention, the adjustment precision is improved by adopting a thread matching mode and adopting bolt adjustment;

further, a protective mirror is installed in a tube of the third incident tube between the air knife and the first reflecting mirror.

The laser welding head protective device has the advantages that the protective mirror is arranged to prevent laser from striking the surface of a material to cause reflection and damage to internal parts of the laser welding head.

Preferably, the moving assembly includes a first linear module for driving the laser welding head to move linearly back and forth on an x-axis of the three-dimensional coordinate system, a second linear module for driving the laser welding head to move linearly back and forth on a y-axis of the three-dimensional coordinate system, and a third linear module for driving the laser welding head to move linearly back and forth on a z-axis of the three-dimensional coordinate system.

According to the invention, the three-axis positioning under the three-dimensional coordinate system is realized through the first to third linear modules, so that the flexible and efficient movement of the laser welding head can be ensured, the adjustable parameters of the welding process can be ensured, the free positioning before welding and the timely adjustment of the welding position in the welding process are facilitated, and the fixation of the laser welding head position is avoided.

Preferably, the first linear module is installed on the base, and the second linear module is installed on a sliding table of the first linear module; the third linear module is arranged on the sliding table of the second linear module; and the sliding table of the third linear module is provided with a fixed part of the rotating disc.

Furthermore, two stroke limit positions close to the first linear module, two stroke limit positions close to the second linear module and two stroke limit positions close to the third linear module are provided with limit sensors.

According to the invention, by arranging the limit sensor, the phenomenon that the welding head continues to drive the linear module after moving to the limit position due to the error operation of an operator is avoided.

Preferably, the adjusting device adopts the lead screw linear module to ensure the adjusting precision of the rotation axis of the laser welding head.

Further, a camera is installed on the fixing portion of the rotating disc, and a camera of the camera horizontally faces the part to be welded.

The invention also provides an all-position laser welding method suitable for the system, which comprises the following steps:

step 1: selecting a tool matched with a to-be-welded part, fixing the tool on a tool platform, and selecting a corresponding shielding gas device;

step 2: grinding a part to be welded of a part to be welded and the periphery of the part to be welded, and wiping the part to be welded and the periphery of the part to be welded by using alcohol;

and step 3: installing the part to be welded on a tool, and enabling a gas blowing opening of a shielding gas device to face the part to be welded of the part to be welded; adjusting the gap between the two sections of the main bodies of the parts to be welded to ensure that the gap is within 0.2 mm;

and 4, step 4: focusing is carried out through the laser spots and the camera, focusing of an initial position is required during focusing, and after focusing of the initial position is finished, the laser welding head is rotated clockwise or anticlockwise to the position which is spaced by 90 degrees, 180 degrees and 270 degrees on the circumference from the initial position for focusing; then the laser welding head is rotated to the initial position and the position of 180 degrees to respectively perform spot welding on the parts to be welded; the power is 500W during spot welding, and the time is 0.5 s;

and 5: checking and confirming that the tool is not interfered with the welding process; setting the highest welding power to 1400W and the rotating speed to 35r/min on the control host according to the welding process; starting the shielding gas device, and controlling the welding process through a CNC system arranged in the control host; the welding power at the beginning section of welding is gradually increased, the welding power at the ending section of welding is gradually reduced, and the number of the rotation cycles of the laser welding head is 1.2 cycles when the CNC system arranged in the control host machine is preset with welding;

step 6: when the welding is finished, operating the laser welding head on the control host machine to return to the initial position, and closing the protective gas device; and taking down the to-be-welded part and the tool which finish welding, polishing and wiping the surface of the welding seam, and finishing the whole welding process.

According to the invention, after the welding part is fixed, laser welding to a central shaft or interference of a tool on subsequent welding work is avoided in a laser spot welding manner; the all-position welding of the small-diameter thin-walled tube is realized through the steps; and the relative fixation of the welding seam clearance in the initial locking state is ensured.

The laser power of the starting section is gradually increased, the laser power of the ending section is gradually reduced, pits are prevented from being generated in the center of a welding line when laser welding is finished, and the quality of a welding joint is improved.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. the invention designs the mechanism of the laser welding head and installs each reflector; the laser welding head can be driven by the rotating disc, when laser beams are emitted, the laser beams which can be emitted by the laser welding head can rotate +/-450 degrees around a rotating shaft of the rotating disc, and therefore all-position butt welding of thin-walled tubes with the diameters of 5-12mm is achieved; in addition, the invention can realize the adjustment of the focal length and the incident light angle by adjusting the angle of the first reflector, thereby avoiding the use unicity of the device.

2. According to the invention, the moving assembly is arranged, so that the laser welding head can linearly move back and forth on the x axis, the y axis and the z axis of the three-dimensional coordinate system, and the position of the laser welding head can be adjusted through the moving assembly, so that the rotation axis of the laser welding head and the axis of the pipeline to be welded can be in the same straight line.

3. According to the invention, after the welding part is fixed, laser welding to the central shaft or interference of a tool on subsequent welding work is avoided in a laser spot welding manner; the all-position welding of the small-diameter thin-walled tube is realized through the steps; and the relative fixation of the welding seam clearance in the initial locking state is ensured.

The laser power of the starting section is gradually increased, the laser power of the ending section is gradually reduced, a pit is prevented from being generated in the center of a welding line when the laser welding is finished, and the quality of a welding joint is improved.

Drawings

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of the system of the present invention.

Fig. 2 is a schematic structural diagram of a moving assembly according to the present invention.

Fig. 3 is a schematic layout diagram of the incident pipe according to the present invention.

Fig. 4 is a schematic diagram of the reflection principle of the reflector of the present invention.

Fig. 5 is a schematic structural view of the tool of the present invention.

Fig. 6 is a schematic diagram of the laser power variation with time in embodiment 1 of the present invention.

Fig. 7 is a detailed schematic view of the adjustment assembly of the present invention.

Fig. 8 is a welding flow diagram of the present invention.

Description of the reference numerals: 1. welding a head by laser; 2. rotating the disc; 3. a moving assembly; 4. a control host; 5. a display end; 6. a laser transmitter; 7. a controller; 8. a water cooling machine; 9. a camera; 10. a tooling platform; 11. a water-cooled tube; 12. a base; 13. a set screw; 14. a shielding gas base; 15. entering an air pipe; 16. a first outlet pipe; 17. a second outlet pipe; 18. a tooling base; 19. a part to be welded; 20. welding the part to be welded; 21. a central shaft; 22. a first end plate; 23. a second end plate; 101. an incident end; 102. a first incident tube; 103. a second incident tube; 104. a third incident tube; 105. a third reflector; 106. a second reflector; 107. a first reflector; 108. a focusing section; 109. protective glasses; 110. an air knife; 111. an end cap; 112. a bolt; 113. a binaural seat; 114. a sleeve; 115. locking the nut; 301. a first linear module; 302. a second linear module; 303. a third linear module.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. The components of embodiments of the present application, generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present application, as presented in the figures, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present application without making any creative effort, shall fall within the protection scope of the present application.

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings;

referring to fig. 1, 3 and 4, an all-position laser welding system comprises a control system connected with a laser welding head 1, a tooling platform 10 for bearing a welding part and a laser emitter 6 for providing energy for welding for the laser welding head 1; the laser welding head 1 comprises a first incident pipe 102, wherein one end of the first incident pipe 102 is connected with an incident end 101 which is connected with a laser emitter 6 through an optical fiber; the other end of the first incident tube 102 is vertically connected with one end of a second incident tube 103, and the other end of the second incident tube 103 is vertically connected with a third incident tube 104;

an air knife 110 with an emitting end facing the tool platform 10 is installed at one end, away from the second incident pipe 103, of the third incident pipe 104, and a first reflecting mirror 107 capable of reflecting laser to the air knife 110 and adjusting the angle is installed at the intersection position of the third incident pipe 104 and the second incident pipe 103;

a second reflecting mirror 106 for reflecting laser light to the first reflecting mirror 107 is installed at a position where the second incident pipe 103 intersects with the first incident pipe 102;

a third reflector 105 for reflecting laser light to a second reflector 106 is arranged at one end of the first incident pipe 102 close to the incident end 101;

a focusing part 108 is arranged in the second incidence pipe 103;

the incident end 101 is mounted on a rotating portion of the rotating disk 2.

The invention designs the mechanism of the laser welding head 1 and installs each reflector; the laser welding head 1 can be driven by the rotating disk 2, when laser beams are emitted, the laser beams which can be emitted by the laser welding head 1 can rotate +/-450 degrees around the rotating shaft of the rotating disk 2, and therefore all-position butt welding of thin-walled tubes with the diameters of 5-12mm is achieved; in addition, the invention can realize the adjustment of the focal length and the incident light angle by adjusting the angle of the first reflector 107, thereby avoiding the use unicity of the device.

The rotating disc 2 adopts the existing electric rotating platform;

referring to fig. 1, the fixed part of the rotating disc 2 is mounted on a moving assembly 3 which drives the laser welding head 1 to make linear reciprocating motion on the x-axis, the y-axis and the z-axis of the three-dimensional coordinate system; the rotating disc 2 and the moving assembly 3 are both electrically connected with a controller 7.

According to the invention, the moving assembly 3 is arranged, so that the laser welding head 1 can linearly move back and forth on the x axis, the y axis and the z axis of the three-dimensional coordinate system, and the position of the laser welding head 1 can be adjusted through the moving assembly 3, so that the rotation axis of the laser welding head 1 and the axis of the pipeline to be welded can be in the same straight line.

Referring to fig. 1, the control system comprises a control host 4, a display end 5 electrically connected with the control host 4, a controller 7 electrically connected with the control host 4, and a water cooling machine 8 respectively connected with the laser emitter 6 and the laser welding head 1 through a water cooling pipe 11;

the control host 4 is electrically connected with the laser transmitter 6.

Referring to fig. 3, 4 and 7, the angle of the first reflecting mirror 107 is adjusted based on an angle adjusting assembly, which includes a square end cap 111 mounted on the outer wall of the tube body at the intersection of the second incident tube 103 and the third incident tube 104, a bolt 112 is mounted at each of four corners of the end cap 111, the bolts 112 penetrate through the end cap 111 and the outer wall of the tube body, extend into the tube at the intersection of the second incident tube 103 and the third incident tube 104, and the bolts 112 are in threaded fit with the penetrating holes on the end cap 111;

the ends of two bolts 112 close to the second incident tube 103 are mounted on the first reflector 107 in an articulated manner; the ends of the two bolts 112 close to the third incident pipe 104 are rotatably mounted with sleeves 114, and the sleeves 114 are assembled with the first reflecting mirror 107 in an articulated manner.

Specifically, referring to fig. 7, two ear seats 113 are installed at positions close to four corners of the first reflector 107, a bolt 112 close to one side of the second incident tube 103 penetrates through the end cover 111 in a threaded manner, and an end of the bolt is hinged to the two ear seats 113; a bolt 112 near the third incident tube 104 penetrates the end cover 111 in a threaded fit manner, and the end of the bolt is rotatably installed in a sleeve 114, and the sleeve 114 is hinged with the double-lug seat 113.

Referring to fig. 7, a locking nut 115 is further installed between the hexagonal tightening part of the bolt 112 and the end cap 111, and the locking nut 115 is screw-engaged with the bolt 112 so that locking can be performed by the locking nut 115 after the angle of the first reflecting mirror 107 is adjusted.

According to the invention, the adjustment precision is improved by adopting a thread matching mode and adopting the bolt 112 for adjustment;

referring to fig. 4, the optimal range of angular adjustment of the first mirror 107 of the present invention is: the angle between the laser line reflected by the second mirror 106 and the laser line reflected by the first mirror 107 is between 90 degrees and 100 degrees.

Referring to fig. 3, a protective mirror 109 is installed inside the tube of the third incident tube 104 between the air knife 110 and the first reflecting mirror 107.

Referring to fig. 1 and fig. 2, the moving assembly 3 includes a first linear module 301 for driving the laser welding head 1 to move back and forth linearly on the x-axis of the three-dimensional coordinate system, a second linear module 302 for driving the laser welding head 1 to move back and forth linearly on the y-axis of the three-dimensional coordinate system, and a third linear module 303 for driving the laser welding head 1 to move back and forth linearly on the z-axis of the three-dimensional coordinate system.

According to the invention, the three-axis positioning under the three-dimensional coordinate system is realized through the first to third linear modules 303, so that the flexible and efficient movement of the laser welding head 1 can be ensured, the adjustable parameters of the welding process can be ensured, the free positioning before welding and the timely adjustment of the welding position in the welding process are facilitated, and the position fixation of the laser welding head 1 is avoided.

Referring to fig. 1 and 2, the first linear module 301 is mounted on the base 12, and the second linear module 302 is mounted on the sliding table of the first linear module 301; the third linear module 303 is mounted on the sliding table of the second linear module 302; and the fixing part of the rotating disk 2 is arranged on the sliding table of the third linear module 303.

Referring to fig. 1 and 2, limit sensors are disposed at two travel limit positions near the first linear module 301, at two travel limit positions near the second linear module 302, and at two travel limit positions near the third linear module 303.

According to the invention, by arranging the limit sensor, the problem that the welding head continues to drive the linear module after moving to the limit position due to the wrong operation of an operator is avoided.

Preferably, the electric screw linear module is adopted in the invention, so that the adjustment precision of the rotation axis of the laser welding head 1 is ensured.

Referring to fig. 1, a camera 9 is mounted on the fixed portion of the rotating disk 2, and the camera of the camera 9 faces horizontally to a member to be welded 19.

The camera 9 is a CCD camera 9, the to-be-welded part 19 is enlarged to 20 times through the camera 9, the accurate positioning of the rotating shaft of the rotating disc 2 can be realized by matching with a CNC system, the coincidence of the incident laser center and the welding seam center of the to-be-welded part 19 can be ensured, and the error between the incident laser center and the welding seam center is kept to be less than 0.1 mm.

Referring to fig. 5, the tooling of the present invention includes a central shaft 21 with threads at two ends, a first end plate 22 and a second end plate 23 are respectively sleeved at two ends of the central shaft 21, and a nut is installed on the central shaft 21 between the first end plate 22 and the end of the central shaft 21 and the second end plate 23; the tool further comprises a tool base 18 used for being assembled with the tool platform 10, a groove used for preventing the part to be welded 19 is formed in the tool base 18, a threaded hole penetrating through the wall of the groove is formed in the wall of the groove, a set screw 13 extends into the threaded hole, and the end of the set screw 13 can be tightly fixed on the part to be welded 19.

The shielding gas device comprises a shielding gas base 14, wherein a gas inlet pipe 15 is arranged on the shielding gas base 14, the gas inlet pipe 15 is communicated with a first gas outlet pipe 16 and a second gas outlet pipe 17, and the first gas outlet pipe 16 and the second gas outlet pipe 17 are arranged at an interval of 180 degrees by taking the axis of a central shaft 21 as a rotating shaft.

When the tool is used, the bodies at two ends of the part to be welded 19 are sleeved on the central shaft 21, the nuts are rotated to enable the first end plate 22 and the second end plate 23 to be tightly attached to two ends of the part to be welded 19, the part to be welded 19 is fixed, the fixed part to be welded 19 is placed in the groove of the tool base 18, the set screw 13 is screwed in, and the part to be welded 19 is fixed in the groove; after the fixing is completed, the whole tool is fixed on the tool platform 10, and the whole position of the shielding gas device is adjusted, so that the gas outlet ends of the first gas outlet pipe 16 and the second gas outlet pipe 17 face towards the welding part.

It should be noted that, the whole device of the present invention is powered by an external power supply, and on the basis of understanding the implementation principle of the present invention, it is a conventional technical means in the art to power the corresponding part by using the power supply, and therefore, the above description is not repeated in the present invention.

After the technical scheme is adopted, the focusing mode of the invention has two modes;

the first method comprises the following steps: firstly, ensuring that a focusing part 108 is unchanged, placing a test plate with known thickness on a tool platform 10, controlling a laser welding head 1 to move to a position approximately coinciding with the surface of the test plate, and adjusting a focusing knob of a camera 9 to enable a monitoring software picture in a display screen to be gradually clear; and the center line of the test plate is coincident with the axis of the central rotating shaft of the rotating disk 2;

measuring the section radius of the part 19 to be welded in advance, fixing the prepared part 19 to be welded to the tool platform 10 by using a proper welding tool, keeping the part 19 to be welded stationary relative to the base 12, and controlling the laser welding head 1 to move to the display screen so that the surface of the part 19 to be welded can be clearly seen; then reducing the vertical distance from the surface of the laser welding head 1 to the tail end of the laser welding head 1, wherein the length is the radius of the section of the workpiece 19 to be welded; and finally, adjusting the focusing part 108 to enable the picture in the display screen to be gradually clear, and controlling the laser welding head 1 to move to the 20 positions of the part to be welded, which can be seen clearly, according to the picture to finish accurate focusing.

Secondly, for the all-position welding which requires low welding quality requirement or needs defocusing, firstly, ensuring that a focusing part 108 is unchanged, fixing the to-be-welded part 19 to the tooling platform 10, then aligning a central shaft 21 of the to-be-welded part 19 with the axis of a rotating shaft of the rotating disk 2 by visual inspection, adjusting a focusing knob of the camera 9 to enable the surface of a section of the to-be-welded part 19 to be seen in the display screen, then controlling the laser welding head 1 to rotate to respectively rotate to an initial position, clockwise to a position which is 90 degrees away from the initial position on the circumference, clockwise to a position which is 180 degrees away from the initial position on the circumference, clockwise to a position which is 270 degrees away from the initial position on the circumference, controlling the distance from the tail end of the laser welding head 1 to the surface of the to-be-welded part 19 to be moved to enable the surface of the to-be-welded part 19 to be seen in the display screen, focusing can also be regarded as completed, and the method is coarser but more convenient;

and controlling the laser welding head 1 to respectively rotate to an initial position and clockwise to a position which is 180 degrees away from the initial position on the circumference, and setting the laser power to be less than or equal to 500W for a short welding process of about 0.2-0.5 seconds to a fixed point so as to ensure that the welding seam gap is relatively accurate.

The parts 19 to be welded in the invention are pipelines with the wall thickness of 0.5 mm to 2mm and the pipe diameter of 5-12 mm.

Referring to fig. 8, an all-position laser welding method includes the steps of:

step 1: selecting a tool matched with a part 19 to be welded, fixing the tool on a tool platform 10, and selecting a corresponding protective gas device;

and 2, step: grinding the 20 position of the part to be welded 19 and the periphery of the 20 position of the part to be welded, and wiping the 20 position of the part to be welded and the periphery of the 20 position of the part to be welded by using alcohol;

and 3, step 3: installing the part to be welded 19 on the tool, and enabling a gas blowing opening of the shielding gas device to face a part to be welded 20 of the part to be welded 19; and adjusting the gap between the two sections of the bodies of the parts to be welded 19 to ensure that the gap is within 0.2 mm;

and 4, step 4: focusing is carried out through the laser spots and the camera 9, focusing of an initial position is required during focusing, and after the focusing of the initial position is finished, the laser welding head 1 is rotated clockwise or anticlockwise to the position which is spaced by 90 degrees, 180 degrees and 270 degrees on the circumference with the initial position for focusing; then the laser welding head 1 is rotated to the initial position and the position of 180 degrees to respectively perform spot welding on the part to be welded 20; the power is 500W and the time is 0.5s during spot welding;

and 5: checking and confirming that the tool does not interfere with the welding process; setting the highest welding power to 1400W and the rotating speed to 35r/min on the control host 4 according to the welding process; starting a protective gas device, and controlling a welding process through a CNC system arranged in the control host 4; the welding power at the beginning section of welding is gradually increased, the welding power at the ending section of welding is gradually decreased, and the number of the rotation cycles of the laser welding head 1 is 1.2 cycles when welding is preset in a CNC system arranged in the control host 4;

step 6: when the welding is finished, operating the laser welding head 1 on the control host machine 4 to return to the initial position, and closing the protective gas device; and taking off the part 19 to be welded and the tool which finish welding, polishing and wiping the surface of the welding seam, and finishing the whole welding process.

After the part to be welded 19 is fixed, the interference of the subsequent welding process of the tool is avoided in a laser spot welding mode; the all-position welding of the small-diameter thin-walled tube is realized through the steps;

The above embodiments only express specific embodiments of the present application, and the description is specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for those skilled in the art, without departing from the technical idea of the present application, several changes and modifications can be made, which all belong to the protection scope of the present application.

Claims

1. An all-position laser welding method is based on an all-position laser welding system and comprises a control system connected with a laser welding head (1), a tool platform (10) bearing a welding part and a laser emitter (6) providing energy for welding for the laser welding head (1); the laser welding head (1) is characterized by comprising a first incident pipe (102), wherein one end of the first incident pipe (102) is connected with an incident end (101) which is connected with a laser emitter (6) through an optical fiber; the other end of the first incident pipe (102) is vertically connected with one end of a second incident pipe (103), and the other end of the second incident pipe (103) is vertically connected with a third incident pipe (104);

an air knife (110) with an emitting end facing the tool platform (10) is installed at one end, away from the second incident pipe (103), of the third incident pipe (104), a first reflecting mirror (107) capable of reflecting laser to the air knife (110) and adjusting the angle is installed at the position where the third incident pipe (104) and the second incident pipe (103) are intersected;

a second reflector (106) for reflecting laser to the first reflector (107) is arranged at the position where the second incidence pipe (103) and the first incidence pipe (102) intersect;

a third reflector (105) for reflecting laser to a second reflector (106) is arranged at one end of the first incident pipe (102) close to the incident end (101);

a focusing part (108) is arranged in the second incidence pipe (103);

the incident end (101) is arranged on a rotating part of the rotating disc (2);

the all-position laser welding method comprises the following steps:

step 1: selecting a tool matched with a part to be welded (19), fixing the tool on a tool platform (10), and selecting a corresponding protective gas device;

step 2: grinding the part to be welded of the part to be welded (19) and the periphery of the part to be welded (20), and wiping the part to be welded (20) and the periphery of the part to be welded (20) by using alcohol;

and step 3: installing a part to be welded (19) on a tool, and enabling a gas blowing opening of a shielding gas device to face a part to be welded (20) of the part to be welded (19); and adjusting the clearance between the two sections of the bodies of the parts (19) to be welded to ensure that the clearance is within 0.2 mm;

and 4, step 4: focusing is carried out through the laser spots and the camera (9), focusing at an initial position is required during focusing, and after the focusing at the initial position is finished, the laser welding head (1) is rotated clockwise or anticlockwise to the position which is spaced by 90 degrees, 180 degrees and 270 degrees on the circumference from the initial position for focusing; then the laser welding head (1) is rotated to the initial position and the position of 180 degrees to respectively carry out spot welding on the part to be welded (20); the power is 500W and the time is 0.5s during spot welding;

and 5: checking and confirming that the tool is not interfered with the welding process; setting the highest welding power to 1400W and the rotating speed to 35r/min on the control host (4) according to the welding process; starting a protective gas device, and controlling a welding process through a CNC system arranged in a control host (4); the welding power at the beginning section of welding is gradually increased, and the welding power at the end section of welding is gradually reduced; when welding is preset in a CNC system arranged in the control host (4), the number of the rotation cycles of the laser welding head (1) is 1.2 cycles;

step 6: when the welding is finished, operating the laser welding head (1) on the control host (4) to return to the initial position, and closing the protective gas device; and taking down the part to be welded (19) and the tool which finish the welding work, polishing and wiping the surface of the welding seam, and finishing the whole welding process.

2. An all-position laser welding method according to claim 1, characterized in that the fixed part of the rotating disc (2) is mounted on a moving assembly (3) which drives the laser welding head (1) to make a straight back and forth movement on the x-axis, y-axis and z-axis of a three-dimensional coordinate system; the rotating disc (2) and the moving assembly (3) are both electrically connected with a controller (7).

3. The all-position laser welding method according to claim 1, wherein the control system comprises a control host (4), a display end (5) electrically connected with the control host (4), a controller (7) electrically connected with the control host (4), and a water cooling machine (8) respectively connected with the laser emitter (6) and the laser welding head (1) through a water cooling pipe (11);

the control host (4) is electrically connected with the laser emitter (6).

4. An all-position laser welding method according to claim 1, characterized in that the angle of the first reflector (107) is adjusted based on an angle adjusting assembly, the angle adjusting assembly comprises a square end cover (111) installed on the outer wall of the tube body at the intersection position of the second incident tube (103) and the third incident tube (104), bolts (112) are respectively installed at the positions close to the four corners of the end cover (111), the bolts (112) penetrate through the end cover (111) and the outer wall of the tube body and extend into the tube at the intersection position of the second incident tube (103) and the third incident tube (104), and the bolts (112) are in threaded fit with through holes on the end cover (111);

the ends of two bolts (112) close to the second incident pipe (103) are arranged on the first reflector (107) in a hinged mode; the ends of the two bolts (112) close to the third incident pipe (104) are rotatably provided with sleeves (114), and the sleeves (114) are assembled with the first reflector (107) in a hinged manner.

5. An all-position laser welding method according to claim 1, characterized in that a protective mirror (109) is installed inside the tube of the third incident tube (104) between the gas knife (110) and the first reflecting mirror (107).

6. The full-position laser welding method according to claim 2, wherein the moving assembly (3) comprises a first linear module (301) for driving the laser welding head (1) to linearly move back and forth on an x-axis of a three-dimensional coordinate system, a second linear module (302) for driving the laser welding head (1) to linearly move back and forth on a y-axis of the three-dimensional coordinate system, and a third linear module (303) for driving the laser welding head (1) to linearly move back and forth on a z-axis of the three-dimensional coordinate system.

7. An all-position laser welding method according to claim 6, characterized in that the first linear module (301) is mounted on a base (12), and the second linear module (302) is mounted on a slide of the first linear module (301); the third linear module (303) is arranged on the sliding table of the second linear module (302); and the fixing part of the rotating disc (2) is arranged on the sliding table of the third linear module (303).

8. An all-position laser welding method according to claim 6, characterized in that limit sensors are arranged close to the two limit of travel positions of the first linear die set (301), close to the two limit of travel positions of the second linear die set (302), and close to the two limit of travel positions of the third linear die set (303).

9. An all-position laser welding method as claimed in claim 1, characterized in that a camera (9) is mounted on the fixed part of the rotary disc (2), the camera of the camera (9) facing horizontally towards the part to be welded (19).