Welding Method of a Precision Laser Welding Device for Optical Fiber Transmission

Abstract

The present invention discloses a precision laser welding device for optical fiber transmission, comprising: an equipment frame, a laser welding head disposed on the top of the equipment frame, and a three-axis translation mechanism installed on the top of the equipment frame for driving the laser welding head to achieve three-axis movement; a plurality of worktables are fixedly arranged at the inner bottom of the equipment frame, and two tubular workpieces are installed between adjacent worktables, and one end of the tubular workpiece is an elliptical shape inclined at 45°. During laser welding operation, a multi-layer circulating flow is sprayed downward circumferentially at the laser end of the laser welding head, ensuring that the shielding gas uniformly covers the welding area from multiple layers and angles, effectively preventing impurities or oxygen in the air from invading the molten pool, reducing the risk of oxidation and contamination during welding, improving the flow state of the molten pool, enabling possible bubbles to be brought to the surface of the molten pool and escaping, thereby being able to reduce the generation of welding defects and contributing to improving the welding quality.

Description

Technical Field

[0001] The present invention relates to the field of welding technology, particularly to laser beam processing, and specifically to a welding method for a precision laser welding device with fiber optic transmission. Background Art

[0002] In the field of modern industrial manufacturing, especially in industries such as aerospace, automotive manufacturing, and precision instrument manufacturing, extremely high requirements are imposed on the welding quality of pipes. Traditional welding methods, such as arc welding and resistance welding, often have many deficiencies when facing the welding of tubular workpieces with complex shapes and high-precision requirements. Especially when the axes of the tubular workpieces to be welded form a non-coaxial welding posture, it is difficult for traditional welding methods to achieve precise docking and uniform welding.

[0003] Fiber optic transmission laser welding is an advanced welding technology. It uses optical fibers as the transmission medium, couples high-energy laser beams into the optical fibers, and after long-distance transmission, collimates them into parallel light through a collimating mirror and then focuses on the workpiece for welding. However, the existing laser welding devices in the prior art have problems such as insufficient flexibility and unstable welding quality when dealing with the welding of tubular workpieces with different welding trajectories.

[0004] Therefore, it is necessary to improve the deficiencies in the prior art to solve the above problems. Summary of the Invention

[0005] The present invention overcomes the deficiencies of the prior art and provides a welding method for a precision laser welding device with fiber optic transmission.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a precision laser welding device with fiber optic transmission, comprising: an equipment frame, a laser welding head arranged on the top of the equipment frame for precision laser welding through fiber optic transmission, and a three-axis translation mechanism installed on the top of the equipment frame for driving the laser welding head to achieve three-axis movement;

[0007] A plurality of worktables are fixed to the inner bottom of the equipment frame. Two tubular workpieces are installed between adjacent worktables. One end of the tubular workpiece is an elliptical shape inclined at 45°. A control system for realizing fully automatic welding processing by using a controller is installed on one side of the equipment frame;

[0008] A rotation and translation mechanism for driving the tubular workpieces to respectively achieve rotation and translation is arranged on the side of the worktable. A concentric clamping mechanism for clamping the tubular workpieces coaxially at 45° is installed on the rotation and translation mechanism. A circulation component is arranged at the output end of the laser welding head;

[0009] The circulation component includes: an annular square tube fixed to the side of the laser welding head near the output end, several annular tapered tubes fixed to the bottom of the annular square tube, and a connecting tube fixed to the side of the annular square tube.

[0010] In a preferred embodiment of the present invention, the interiors of several of the annular tapered tubes and the connecting tube are all in communication with the interior of the annular square tube, and the cross-sectional area at the connection of the annular tapered tube and the annular square tube is larger than the cross-sectional area of the bottom of the annular tapered tube.

[0011] In a preferred embodiment of the present invention, the rotation and translation mechanism includes: a translation component arranged on one side of the workbench for converting rotational motion into linear motion; the drive source in the translation component is electrically connected to the control system.

[0012] In a preferred embodiment of the present invention, the rotation and translation mechanism further includes: a servo motor fixed to one side of the workbench, a driving bevel gear fixed to the output end of the servo motor, and a rotating shaft rotatably connected to the workbench; one end of the rotating shaft is fixed to the translation component, and a driven bevel gear is fixed to the other end. The driving bevel gear and the driven bevel gear are meshed, and the servo motor is electrically connected to the control system.

[0013] In a preferred embodiment of the present invention, the concentric clamping mechanism includes: a conical block fixed to the top of the translation plate in the translation component, a positioning post fixed to one side of the conical block, and several through slots opened on the side of the positioning post; several coaxial ejecting components are arranged inside the positioning post; the cross-sectional shape of the conical block is an isosceles right triangle, with the right-angle side fixed to the top of the translation plate in the translation component and the inclined side fixed to one end of the positioning post.

[0014] In a preferred embodiment of the present invention, the coaxial ejecting component includes: a fixed cylinder fixed inside the positioning post, a rotating piece rotatably connected inside the fixed cylinder, and a micro motor fixed inside the fixed cylinder; several arc-shaped chutes are opened on the surface of the rotating piece, several ejecting blocks are slidably connected inside several of the through slots, a convex block is fixed to the side of the ejecting block facing the rotating piece, and the side of the convex block is clamped inside the arc-shaped chute. The inner side of the tubular workpiece is sleeved on the side of the positioning post.

[0015] In a preferred embodiment of the present invention, the output end of the micro motor is fixed to one side of the rotating piece, and the micro motor is electrically connected to the control system; the positioning post is a hollow cylindrical shape, and the fixed cylinder is a cylindrical shape with one end open and the other end closed; several of the arc-shaped chutes are circumferentially and evenly distributed on the surface of the rotating piece, and the number and distribution pattern of the ejecting blocks and the convex blocks are the same as those of the arc-shaped chutes.

[0016] In a preferred embodiment of the present invention, the top block is provided with anti-slip patterns on the side facing the outside of the through groove and contacts the inner side of the tubular workpiece.

[0017] The present invention provides a welding method for a precision laser welding device for optical fiber transmission, including the following steps:

[0018] S1. Two tubular workpieces to be welded are coaxially clamped at 45° on the rotary translation mechanism through a concentric clamping mechanism.

[0019] S2. Through the rotary translation mechanism, the inclined ends of the two tubular workpieces between adjacent worktables at 45° are driven to approach each other to a suitable laser welding gap, so that the included angle between the two tubular workpieces is 90°.

[0020] S3. Determine the key parameters during laser welding, calculate the welding movement speeds of the elliptical ends of the tubular workpieces at the major axis and minor axis respectively, and program the automatic welding procedure for the welding movement speeds and key parameters through the control system.

[0021] S4. One end of the connecting pipe is externally connected to the argon gas delivery device, and the control system controls the three-axis translation mechanism to drive the laser welding head to translate in the X-axis, Y-axis or Z-axis directions respectively, so that the laser welding head moves to the welding position between the two tubular workpieces.

[0022] S5. The control system controls the laser welding head to perform laser welding operations, and at the same time, the rotary translation mechanism drives the two tubular workpieces to rotate respectively at the welding movement speeds at the major axis and minor axis. During the rotation, the three-axis translation mechanism drives the laser welding head to move in the X-axis, Y-axis or Z-axis directions following the rotation state.

[0023] S6. During the laser welding operation, argon gas is transported from the argon gas delivery device to the annular square pipe through the connecting pipe, and is sprayed downward by a plurality of annular tapered pipes at the bottom of the annular square pipe, so as to form a multi-layer circulating protective gas at the bottom of the laser welding head and the circumference of the laser welding point to improve the welding quality.

[0024] S7. After the welding of the welding parts of the two tubular workpieces is completed, control the concentric clamping mechanism to cancel the clamping of the tubular workpieces, control the rotary translation mechanism to drive the two tubular workpieces to rotate downward, and slowly drive the concentric clamping mechanism to move toward the worktable side, so that the welded tubular workpieces are separated from the concentric clamping mechanism under the action of gravity to complete the material taking, thereby completing the use.

[0025] The present invention solves the defects in the background technology and has the following beneficial effects:

[0026] (1)The present invention provides a welding method for a precision laser welding device with optical fiber transmission. By using optical fiber transmission for laser welding, it can handle the right-angle welding area formed between tubular workpieces, enabling flexible transmission and non-contact high-precision welding, with good flexibility. At the same time, during laser welding, by rotating while respectively matching the welding movement speeds in the long axis and short axis, it can ensure uniform energy distribution at the long axis and short axis positions, avoiding uneven weld width or depth and burn-through caused by too fast or too slow speed. Furthermore, after welding, a better weld depth-to-width ratio can be obtained, which helps to form a uniform weld and reduce welding defects such as pores and cracks, thereby improving the mechanical properties and tolerance after welding.

[0027] (2)In the present invention, by setting a circulating component at the output end of the laser welding head, during laser welding operation, through the cooperation of the annular square tube, several annular tapered tubes and the connecting tube, it can be sprayed circumferentially downward in a multi-layer circulating shape at the laser end of the laser welding head, ensuring that the shielding gas uniformly covers the welding area from multiple layers and angles, effectively preventing impurities or oxygen in the air from invading the molten pool, reducing the risk of oxidation and contamination during welding. At the same time, it can improve the flow state of the molten pool, bringing possible bubbles to the surface of the molten pool and escaping, thereby reducing the probability of pore formation after welding, and thus reducing the generation of welding defects and helping to improve the welding quality.

[0028] (3)In the present invention, by installing a concentric clamping mechanism on the rotary translation mechanism, when clamping the tubular workpiece, through the cooperation of the tapered block, positioning column, several through slots and several coaxial ejecting components, the tubular workpiece can be concentrically clamped on the side of the positioning column and form a 45° angle with the plane. At the same time, since one end of the tubular workpiece is an elliptical shape with a 45° inclination, the axes between the two tubular workpieces concentrically clamped between adjacent worktables will be in a perpendicular 90° angle state, ensuring the accurate docking of the elliptical ends of the two tubular workpieces to be welded. Furthermore, during laser welding, it can avoid uneven distribution of thermal stress and mechanical stress generated by welding due to docking offset, making it easier to ensure the uniformity and consistency of the weld, and helping to reduce the occurrence of welding defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings;

[0030] Figure 1 is a three-dimensional structure diagram of a preferred embodiment of the present invention;

[0031] Figure 2 is the front view structure diagram of the preferred embodiment of the present invention;

[0032] Figure 3 is the structure diagram of the connection part between the laser welding head and the circulation component of the preferred embodiment of the present invention and its partial enlarged view;

[0033] Figure 4 is the separation structure diagram of the tubular workpiece and the concentric clamping mechanism of the preferred embodiment of the present invention;

[0034] Figure 5 is the semi-sectional structure diagram of the positioning column and the fixed cylinder of the preferred embodiment of the present invention;

[0035] Figure 6 is the unfolded structure diagram of several top blocks of the preferred embodiment of the present invention;

[0036] In the figure: 1. Equipment frame; 2. Laser welding head; 3. Three-axis translation mechanism; 4. Workbench; 5. Tubular workpiece; 6. Control system; 7. Rotary translation mechanism; 71. Translation component; 72. Servo motor; 73. Active bevel gear; 74. Rotating shaft; 75. Driven bevel gear; 8. Concentric clamping mechanism; 81. Conical block; 82. Positioning column; 83. Through groove; 84. Fixed cylinder; 85. Rotating piece; 86. Micro motor; 87. Arc-shaped chute; 88. Top block; 89. Convex block; 9. Circulation component; 91. Annular square pipe; 92. Annular tapered pipe; 93. Connecting pipe. Specific embodiments

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0038] In the following description, many specific details are set forth in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0039] In the description of this application, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of this application. In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Therefore, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of this invention, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0040] In the description of this application, it should be noted that unless otherwise clearly specified and defined, the terms "install", "connect", "couple" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood through specific circumstances.

[0041] As Figure 1 , Figure 2 and Figure 3 shown, a precision laser welding device for optical fiber transmission includes: an equipment frame 1, a laser welding head 2 arranged on the top of the equipment frame 1 for precision laser welding through optical fiber transmission, and a three-axis translation mechanism 3 installed on the top of the equipment frame 1 for driving the laser welding head 2 to achieve three-axis movement; several workbenches 4 are fixed at the inner bottom of the equipment frame 1, and two tubular workpieces 5 are installed between adjacent workbenches 4. One end of the tubular workpiece 5 is an elliptical shape inclined at 45°. A control system 6 for realizing fully automatic welding processing by using a controller (PLC) is installed on one side of the equipment frame 1; a rotation and translation mechanism 7 for driving the tubular workpiece 5 to respectively achieve rotation and translation is arranged on the side of the workbench 4. A concentric clamping mechanism 8 for 45° coaxial clamping of the tubular workpiece 5 is installed on the rotation and translation mechanism 7. A circulation component 9 is arranged at the output end of the laser welding head 2; the circulation component 9 includes: an annular square tube 91 fixed on the side of the laser welding head 2 near the output end, several annular tapered tubes 92 fixed at the bottom of the annular square tube 91, and a connecting tube 93 fixed on the side of the annular square tube 91.

[0042] It should be noted that the interiors of several annular tapered pipes 92 and connecting pipes 93 are all in through connection with the interior of the annular square pipe 91. The cross-sectional area at the connection between the annular tapered pipe 92 and the annular square pipe 91 is larger than the cross-sectional area at the bottom of the annular tapered pipe 92. The several annular tapered pipes 92 are evenly distributed at the bottom of the annular square pipe 91 in a linear array; the laser welding head 2 uses fiber optic transmission of the prior art for precise laser welding. Using an optical fiber as the transmission medium, a high-energy laser beam is coupled into the optical fiber. After long-distance transmission, it is collimated into parallel light by a collimating mirror and then focused on the workpiece for welding; the control method of the control system 6 and the control circuit for realizing fully automatic welding processing belong to the prior art and can be realized by a person skilled in the art through programming, which belongs to the common general knowledge in this field. Therefore, the control method and modules are not explained in detail in this application and are not elaborated here; before laser welding, one end of the connecting pipe 93 is connected to the gas delivery pipe in an external argon gas delivery device. During laser welding operation, argon gas is delivered to the connecting pipe 93 through the argon gas delivery device, input into the interior of the annular square pipe 91 through the connecting pipe 93, and ejected downward by the multiple annular tapered pipes 92 at the bottom of the annular square pipe 91. At the same time, since the cross-sectional area at the connection between the annular tapered pipe 92 and the annular square pipe 91 is larger than the cross-sectional area at the bottom of the annular tapered pipe 92, when the argon gas flows from the annular square pipe 91 into the annular tapered pipe 92 and flows out, the internal cross-sectional area gradually decreases in sequence, and the argon gas can obtain a larger flow velocity and be ejected circumferentially downward in a circulating flow shape at the laser end of the laser welding head 2. And because the several annular tapered pipes 92 are evenly distributed at the bottom of the annular square pipe 91 in a linear array, the argon gas ejected from the bottoms of the multiple annular tapered pipes 92 can form a spraying effect of multiple circulating flows, which can ensure that the shielding gas uniformly covers the welding area from multiple levels and angles, effectively preventing impurities or oxygen in the air from invading the molten pool, reducing the risk of oxidation and contamination during welding, and at the same time being able to improve the flow state of the molten pool, making possible bubbles be brought to the surface of the molten pool and escape, thereby reducing the probability of pore formation after welding, and thus being able to reduce the generation of welding defects and contribute to improving the welding quality.

[0043] Specifically, according to the continuity equation in fluid mechanics, when a gas passes through a contracting or expanding pipe, the flow velocity changes with the change of the pipe cross-sectional area. In the case of a contracting pipe, the flow velocity of the gas increases because the gas flow rate must be equal at any two points in the pipe. The Bernoulli equation describes the relationship between flow velocity, pressure, and fluid potential energy in an ideal fluid. When a gas flows from a larger pipe into a section with a suddenly reduced diameter, the flow velocity increases, and at the same time, the pressure of the fluid decreases. This pressure difference can push the gas to accelerate and flow out.

[0044] In a possible design, the three-axis translation mechanism 3 specifically includes: a Y-axis translation component for driving the laser welding head 2 to translate in the Y-axis direction, an X-axis translation component for driving the Y-axis translation component and the laser welding head 2 to translate in the X-axis direction, and a Z-axis translation component for driving the X-axis translation component, the Y-axis translation component, and the laser welding head 2 to translate in the Z-axis direction; wherein, the X-axis translation component is vertically arranged perpendicular to the Y-axis translation component and is horizontally arranged perpendicular to the Z-axis translation component in the plane. The driving principles of the X-axis translation component, the Y-axis translation component, and the Z-axis translation component are the same, and each at least includes: a support plate for connection and support, a power source for providing driving force, a limiting member for limiting the translation path, and a translation plate driven to move. The specific structure is a mechanical structure in the prior art that can convert rotational motion into linear motion, which belongs to the common knowledge in the field. Therefore, the control method and structure are not explained in detail in this application and are not elaborated here.

[0045] As Figure 4 shown, in some embodiments, the rotary translation mechanism 7 includes: a translation component 71 disposed on one side of the workbench 4 for converting rotational motion into linear motion; the drive source in the translation component 71 is electrically connected to the control system 6.

[0046] It should be noted that the driving principle, control method, and structural composition of the translation component 71 are the same as those of the X-axis translation component, the Y-axis translation component, or the Z-axis translation component, and they are all mechanical structures in the prior art that can convert rotational motion into linear motion; the concentric clamping component mechanism is located on the translation plate in the translation component 71. When the tubular workpiece 5 passes through the concentric clamping mechanism 8 and is coaxially clamped at a 45° angle on the translation plate in the translation component 71, the control system 6 controls the power source in the translation component 71 to convert rotational motion into linear motion, which acts on the translation plate, and then drives the tubular workpiece 5 to move towards the adjacent tubular workpiece 5 until the 45°-inclined ends of the two tubular workpieces 5 are close to each other to an appropriate laser welding gap, so that the included angle between the two tubular workpieces 5 is 90°. The appropriate joint gap between the two tubular workpieces 5 helps the uniform transfer of heat and the stable formation of the molten pool during the welding process, thereby improving the forming quality and mechanical properties of the weld seam.

[0047] In some embodiments, the rotary translation mechanism 7 further includes: a servo motor 72 fixed to one side of the workbench 4, a driving bevel gear 73 fixed to the output end of the servo motor 72, and a rotating shaft 74 rotatably connected to the workbench 4; one end of the rotating shaft 74 is fixed to the translation component 71, and the other end is fixed with a driven bevel gear 75. The driving bevel gear 73 and the driven bevel gear 75 are engaged, and the servo motor 72 is electrically connected to the control system 6.

[0048] It should be noted that during the laser welding process, the control system 6 controls the servo motor 72 to start, driving the driving bevel gear 73 at the output end to rotate. Through meshing with the driven bevel gear 75, it can drive the driven bevel gear 75 and the rotating shaft 74 on one side to rotate synchronously. At the same time, since one end of the rotating shaft 74 is fixed to the translation assembly 71, it can drive the translation assembly 71 and the tubular workpiece 5 to rotate on one side of the workbench 4. Among them, through the precise meshing transmission of the driving bevel gear 73 and the driven bevel gear 75, the control system 6 controls the servo motor 72 on the adjacent workbench 4 according to the welding movement speed of the major axis or minor axis of the elliptical end of the tubular workpiece 5, and drives the two tubular workpieces 5 between them to match the rotational speed corresponding to the welding movement speed when welding the major axis or minor axis respectively, so as to achieve the required welding effect.

[0049] As Figure 4 , Figure 5 and Figure 6 shown, in some embodiments, the concentric clamping mechanism 8 includes: a tapered block 81 fixed to the top of the translation plate in the translation assembly 71, a positioning post 82 fixed to one side of the tapered block 81, and a plurality of through grooves 83 opened on the side of the positioning post 82; a plurality of coaxial ejecting components are arranged inside the positioning post 82; the cross-sectional shape of the tapered block 81 is an isosceles right triangle, with the right-angle side fixed to the top of the translation plate in the translation assembly 71, and the inclined side fixed to one end of the positioning post 82.

[0050] It should be noted that the positioning post 82 is a hollow cylindrical shape, and a plurality of through grooves 83 are circumferentially and uniformly distributed in the planar direction of the positioning post 82 and are uniformly distributed in a linear array manner in the vertical direction of the positioning post 82; when clamping the tubular workpiece 5, the tubular workpiece 5 is sleeved on the positioning post 82. After using a plurality of coaxial ejecting components to contact the inner side of the tubular workpiece 5 and concentrically clamping it on the side of the positioning post 82, since the cross-sectional shape of the tapered block 81 is an isosceles right triangle and the inclined side is fixed to one end of the positioning post 82, the tubular workpiece 5 can form a 45° angle with the plane after clamping. At the same time, since one end of the tubular workpiece 5 is an elliptical shape with a 45° inclination, the axes between the two tubular workpieces 5 clamped concentrically between the adjacent workbenches 4 will be in a perpendicular 90° angle state, which can ensure that the elliptical ends to be welded of the two tubular workpieces 5 are accurately butted. Furthermore, during laser welding, it can avoid uneven distribution of thermal stress and mechanical stress generated by welding due to butt offset. Therefore, when dealing with right-angle welding of tubular workpieces 5 with a 45° elliptical cross-section for the welding surface, it is easier to ensure the uniformity and consistency of the weld seam, which helps to reduce the occurrence of welding defects.

[0051] In some embodiments, the coaxial ejection assembly includes: a fixed cylinder 84 fixed inside the positioning post 82, a rotating plate 85 rotatably connected inside the fixed cylinder 84, and a micro motor 86 fixed inside the fixed cylinder 84; several arc-shaped chutes 87 are formed on the surface of the rotating plate 85, several ejector blocks 88 are slidably connected inside several through slots 83, a convex block 89 is fixed on one side of the ejector block 88 facing the rotating plate 85, the side surface of the convex block 89 is clamped inside the arc-shaped chute 87, and the inner side of the tubular workpiece 5 is sleeved on the side surface of the positioning post 82.

[0052] It should be noted that the output end of the micro motor 86 is fixed to one side of the rotating plate 85, and the micro motor 86 is electrically connected to the control system 6; the fixed cylinder 84 is a cylindrical shape with one end open and the other end closed; several arc-shaped chutes 87 are circumferentially and uniformly distributed on the surface of the rotating plate 85, and the number and distribution pattern of the ejector blocks 88 and the convex blocks 89 are the same as those of the arc-shaped chutes 87; the fixed cylinder 84 and the rotating plate 85 are coaxially arranged with the positioning post 82; when the tubular workpiece 5 is sleeved on the side surface of the positioning post 82, the control system 6 controls the micro motor 86 to start, driving the rotating plate 85 at the output end to rotate clockwise inside the fixed cylinder 84. Since several convex blocks 89 on one side of several ejector blocks 88 facing the rotating plate 85 are clamped inside several arc-shaped chutes 87, when the rotating plate 85 and several arc-shaped chutes 87 on its surface rotate, it will cause several convex blocks 89 to slide in a limited manner along the inside of several arc-shaped chutes 87. When several convex blocks 89 slide from one end to the other end along the inside of several arc-shaped chutes 87, it will drive several ejector blocks 88 on one side to slide inside several through slots 83 and synchronously eject towards the outside of the positioning post 82. Furthermore, the outside of several ejector blocks 88 can be made to contact the inside of the tubular workpiece 5, so that the contact points reach the same position as the center of the positioning post 82, thereby enabling the tubular workpiece 5 to be concentrically held on the side surface of the positioning post 82, ensuring their coaxiality, and improving the accuracy of the subsequent butt joint of the welding surfaces of the two tubular workpieces 5.

[0053] In some embodiments, the side surface of the ejector block 88 facing the outside of the through slot 83 is provided with anti-slip lines and contacts the inside of the tubular workpiece 5; to ensure the stability of the clamping, after the outside of the ejector block 88 contacts and clamps the inside of the tubular workpiece 5, the anti-slip lines can play an anti-slip and stabilizing effect, thereby helping to improve the reliability and stability of the clamping.

[0054] The present invention provides a welding method for a precision laser welding device with optical fiber transmission, including the following steps:

[0055] S1. Two tubular workpieces 5 to be welded are coaxially clamped at a 45° angle on the rotary translation mechanism 7 through the concentric clamping mechanism 8.

[0056] S2, by means of the rotation and translation mechanism 7, driving the ends of the two tubular workpieces 5 between the adjacent workbenches 4 which are inclined at 45° to approach each other to a suitable laser welding gap, so that the two tubular workpieces 5 form an angle of 90°;

[0057] S3, determining the key parameters during laser welding, calculating the welding movement speed of the elliptical end of the tubular workpiece 5 at the major axis and the minor axis respectively, and programming the welding movement speed and the key parameters through the control system 6 for an automated welding program;

[0058] S4, one end of the connecting tube 93 is externally connected to the argon gas delivery device, and the control system 6 controls the three-axis translation mechanism 3 to drive the laser welding head 2 to translate in the direction of the X axis, the Y axis or the Z axis, so that the laser welding head 2 moves to the welding position between the two tubular workpieces 5;

[0059] S5, the control system 6 controls the laser welding head 2 to perform laser welding operation, and at the same time, the rotation translation mechanism 7 drives the two tubular workpieces 5 to rotate at the welding movement speeds of the long axis and the short axis respectively. During the rotation process, the three-axis translation mechanism 3 drives the laser welding head 2 to move in the X-axis, Y-axis or Z-axis direction following the rotation state;

[0060] S6. During the laser welding operation, the argon gas is transported from the connecting pipe 93 to the annular square tube 91 by the argon gas transporting device, and is sprayed downward from the multiple annular cone tubes 92 at the bottom of the annular square tube 91, so that a multi-layered annular protective gas is formed at the bottom of the laser welding head 2 and around the laser welding point to improve the welding quality;

[0061] S7. After completing the welding of the welding parts of the two tubular workpieces 5, the concentric clamping mechanism 8 is controlled to cancel the clamping of the tubular workpiece 5, the rotation and translation mechanism 7 is controlled to drive the two tubular workpieces 5 to rotate downward, and the concentric clamping mechanism 8 is slowly driven to move toward one side of the workbench 4, so that the welded tubular workpiece 5 is separated from the concentric clamping mechanism 8 by gravity to complete the material removal, thereby completing the use.

[0062] In some embodiments, in step S2, the laser welding gap is 0.1-0.5 mm.

[0063] It should be noted that this laser welding device is applied to a hollow circular tubular workpiece 5, and the welding end has an elliptical welding track formed by a 45° section. By using optical fiber transmission for laser welding, it can handle the right-angle welding area formed between the tubular workpieces 5, enabling flexible transmission and non-contact high-precision welding, with good flexibility. At the same time, during laser welding, by rotating while respectively matching the welding movement speeds at the major axis and minor axis, it can ensure uniform energy distribution at the major axis and minor axis positions, avoiding uneven weld width or depth and burn-through caused by too fast or too slow speeds. Furthermore, after welding, a good weld depth-to-width ratio can be obtained, which helps to form a uniform weld and reduce welding defects such as pores and cracks, thereby improving the mechanical properties and tolerance after welding.

[0064] Based on the ideal embodiments of the present invention as an inspiration, through the above description, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed within the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0065] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A welding method for a precision laser welding device with optical fiber transmission, characterized in that, The laser welding device includes: an equipment frame, a laser welding head arranged on the top of the equipment frame for precision laser welding through optical fiber transmission, and a three-axis translation mechanism installed on the top of the equipment frame for driving the laser welding head to achieve three-axis movement; Several workbenches are fixed at the inner bottom of the equipment frame. Two tubular workpieces are installed between adjacent workbenches. One end of the tubular workpiece is an elliptical shape inclined at 45°. A control system for realizing fully automatic welding processing by using a controller is installed on one side of the equipment frame; A rotation and translation mechanism for driving the tubular workpiece to rotate and translate respectively is arranged on the side of the workbench. A concentric clamping mechanism for clamping the tubular workpiece coaxially at 45° is installed on the rotation and translation mechanism. A circulation component is arranged at the output end of the laser welding head; The circulation component includes: an annular square tube fixed on the side of the laser welding head near the output end, several annular tapered tubes fixed at the bottom of the annular square tube, and a connecting tube fixed on the side of the annular square tube; the interiors of several annular tapered tubes and the connecting tube are all communicated with the interior of the annular square tube. The cross-sectional area at the connection of the annular tapered tube and the annular square tube is larger than the cross-sectional area at the bottom of the annular tapered tube; The rotation and translation mechanism includes: a translation component arranged on one side of the workbench for converting rotational motion into linear motion; the driving source in the translation component is electrically connected to the control system; The rotation and translation mechanism further includes: a servo motor fixed on one side of the workbench, a driving bevel gear fixed at the output end of the servo motor, and a rotating shaft rotatably connected to the workbench; one end of the rotating shaft is fixed to the translation component, and the other end is fixed with a driven bevel gear. The driving bevel gear and the driven bevel gear are meshed, and the servo motor is electrically connected to the control system; The concentric clamping mechanism includes: a tapered block fixed on the top of the translation plate in the translation component, a positioning post fixed on one side of the tapered block, and several through grooves opened on the side of the positioning post; several coaxial ejecting components are arranged inside the positioning post; the cross-sectional shape of the tapered block is an isosceles right triangle, the right-angle side is fixed to the top of the translation plate in the translation component, and the inclined side is fixed to one end of the positioning post; The coaxial ejecting component includes: a fixed cylinder fixed inside the positioning post, a rotating piece rotatably connected inside the fixed cylinder, and a micro motor fixed inside the fixed cylinder; several arc-shaped chutes are opened on the surface of the rotating piece. Several ejecting blocks are slidably connected inside several through grooves. A convex block is fixed on the side of the ejecting block facing the rotating piece, and the side of the convex block is clamped inside the arc-shaped chute. The inner side of the tubular workpiece is sleeved on the side of the positioning post; The output end of the micro motor is fixed to one side of the rotating piece, and the micro motor is electrically connected to the control system; the positioning column is a hollow cylindrical shape, and the fixing cylinder is a cylindrical shape with one end open and the other end closed; a plurality of arc-shaped slots are evenly distributed on the surface of the rotating piece in the circumferential direction, and the top block and the convex block are the same in number and distribution as the arc-shaped slots; The side surface of the top block facing the outside of the through slot is provided with anti-slip grooves and contacts the inner side of the tubular workpiece; The welding method of the laser welding device comprises the following steps: S1. Two tubular workpieces to be welded are clamped coaxially on a rotating and translating mechanism at 45 degrees through a concentric clamping mechanism; S2. Drive the ends of two tubular workpieces between adjacent workbenches at an angle of 45° by means of a rotational translation mechanism, and bring them close to each other to a suitable laser welding gap, so that the two tubular workpieces form a 90° angle; S3, determine the key parameters of laser welding, calculate the welding movement speed of the elliptical end of the tubular workpiece at the major axis and the minor axis respectively, and program the welding movement speed and key parameters through the control system for automatic welding program; S4, connecting one end of the connecting tube to an argon gas delivery device, and the control system controls the three-axis translation mechanism to drive the laser welding head to translate in the direction of the X-axis, Y-axis or Z-axis, so that the laser welding head moves to the welding position between the two tubular workpieces; S5. The control system controls the laser welding head to perform laser welding operations. At the same time, the rotation and translation mechanism drives the two tubular workpieces to rotate at the welding movement speeds of the long axis and the short axis respectively. During the rotation process, the three-axis translation mechanism drives the laser welding head to move in the X-axis, Y-axis or Z-axis direction following the rotation state; S6. During the laser welding operation, the argon gas is transported from the connecting pipe to the annular square tube by the argon gas transporting device, and is sprayed downward from the multiple annular cone tubes at the bottom of the annular square tube, so that a multi-layer circular flow of protective gas is formed at the bottom of the laser welding head and the circumference of the laser welding point to improve the welding quality; S7. After the welding of the two tubular workpieces is completed, the concentric clamping mechanism is controlled to cancel the clamping of the tubular workpieces, the rotary translation mechanism is controlled to drive the two tubular workpieces to rotate downward, and the concentric clamping mechanism is slowly driven to move toward one side of the workbench, so that the welded tubular workpiece is separated from the concentric clamping mechanism by gravity to complete the material removal, thereby completing the use.

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