Titanium alloy sheet laser welding equipment

Abstract

The invention relates to the technical field of metal material welding, and discloses titanium alloy sheet laser welding equipment which comprises a laser system, a movement system, a workbench system and a clamping system. The workbench system comprises a basic frame, a plurality of split type floating platens and a linear guide assembly, the split type floating platens are arranged in the welding direction, telescopic gaps are reserved between the split type floating platens, and the split type floating platens are slidably supported on the basic frame through the linear guide assembly. The clamp unit compresses and fixes the workpiece on the upper surface of the split type floating platen, the workpiece drives the split type floating platen to move synchronously during thermal expansion, the restraining effect of frictional resistance on thermal expansion is eliminated, and the butt joint gaps of the full length of a welding seam are kept consistent. The problem of inconsistent welding seam forming caused by accumulated thermal expansion in large-specification titanium alloy sheet laser welding is solved.

Description

Technical Field

[0001] This invention relates to the field of metal material welding technology, and more specifically, to a laser welding device for titanium alloy thin plates. Background Technology

[0002] In laser welding applications of titanium alloy thin plates, the equipment uses a fixture system to fix the workpiece to be welded on the worktable, and the laser beam moves along a predetermined trajectory to complete the welding. During the welding process, the fixture needs to withstand the thermal expansion stress generated by the heat input of the workpiece.

[0003] For large-format titanium alloy sheets exceeding ten meters in length, the welding thermal cycle causes cumulative thermal expansion along the workpiece's length. Existing technology employs a rigid worktable, on which the workpiece is placed and secured by a fixture. The rigid worktable itself does not deform with the workpiece. The fixed support provided by the rigid worktable leads to relative sliding friction between the workpiece and the rigid worktable when the workpiece shifts due to thermal expansion. This sliding friction hinders the workpiece's free expansion, causing a shift in the butt joint gap in the later section of the weld.

[0004] As the welding process progresses, the cumulative thermal expansion and the positional deviation between the fixture constraint points gradually increase, resulting in inconsistent weld width and affecting the uniformity of the overall plate welding quality. This is the main technical problem existing in the technology. Summary of the Invention

[0005] This invention provides a laser welding equipment for titanium alloy thin plates, which solves the technical problem in related technologies where the cumulative thermal expansion during laser welding of large-size titanium alloy thin plates leads to inconsistent weld width.

[0006] This invention discloses a laser welding device for titanium alloy thin plates, comprising a laser system, a motion system, a worktable system, and a clamping system. The laser system includes a laser generator and a laser welding head. The laser generator generates a laser beam, and the laser welding head is connected to the laser generator via an optical fiber. A focusing lens assembly is installed inside the laser welding head. The motion system includes a gantry and a drive mechanism. The gantry spans above the worktable system, and the laser welding head is mounted on the crossbeam of the gantry via a sliding block. The drive mechanism drives the laser welding head to move horizontally. The worktable system includes a basic frame, multiple separate floating platform plates, and a linear guide assembly. The multiple separate floating platform plates are arranged along the welding direction. Each of the separate floating platforms has a telescopic gap. Linear guide components are used to slidably support the separate floating platforms on the base frame. Each separate floating platform is supported by at least two sets of linear guide components. The clamping system includes multiple sets of clamping units, each set of clamping units is installed on the corresponding separate floating platform, and the clamping units press and fix the workpiece to the upper surface of the separate floating platform. The linear guide components include a guide shaft and a linear bearing. The linear bearing is fixed on the base frame, the guide shaft is set along the welding direction, the first end of the guide shaft is fixed to the separate floating platform, the guide shaft passes through the linear bearing and can slide freely relative to the linear bearing along its axial direction.

[0007] Furthermore, the basic frame includes a bottom support frame and a peripheral standing frame. The bottom support frame is made of welded steel sections, and the peripheral standing frame is fixed to the perimeter of the bottom support frame and extends upward.

[0008] Furthermore, the width of the expansion gap between each split floating platform is set to five to twenty millimeters. The expansion gap is used to absorb the relative displacement of adjacent split floating platforms caused by the thermal expansion of the workpiece.

[0009] Furthermore, the split floating platform includes a platform body and a platform bottom fixing seat. The upper surface of the platform body is the workpiece support surface, the platform bottom fixing seat is fixed to the lower surface of the platform body, and the first end of the guide shaft is fixed to the platform bottom fixing seat.

[0010] Furthermore, the linear bearing is a linear ball bearing with a sealing structure. The linear ball bearing has multiple ball cages inside, and the balls circulate axially within the ball cages. The sealing structure is located at both ends of the linear ball bearing.

[0011] Furthermore, each split floating platform is equipped with four sets of linear guide components, which are respectively located at the four corners of the split floating platform. The axes of the four guide shafts are parallel to each other and are all set along the welding direction.

[0012] Furthermore, the first split floating platform is a positioning reference platform. The positioning reference platform is directly fixed to the base frame by bolts. The upper surface of the positioning reference platform is provided with positioning components, including longitudinal positioning blocks and transverse positioning blocks. The longitudinal positioning blocks are fixed to the front edge of the positioning reference platform and perpendicular to the workpiece placement direction. The transverse positioning blocks are fixed to the side edge of the positioning reference platform and parallel to the workpiece placement direction.

[0013] Furthermore, the fixture unit includes a fixture base, a clamping mechanism, and a driving device. The fixture base is fixed to the upper surface of the split floating platform. The clamping mechanism is hinged to the fixture base via a rotating shaft. The clamping mechanism includes a clamping arm and a pressure plate. The first end of the clamping arm is hinged to the fixture base via a rotating shaft, and the second end of the clamping arm is fixedly connected to the pressure plate. The driving device drives the clamping mechanism to rotate around the rotating shaft, so that the pressure plate switches between a raised position and a clamping position.

[0014] Furthermore, the driving device is a pneumatic cylinder, the cylinder body of which is hinged to the fixture base, the piston rod end of which is hinged to the clamping arm, and the lower surface of the pressure plate is provided with an anti-slip layer.

[0015] Furthermore, it also includes a protective gas system, which includes an argon gas supply device and a gas protective cover. The gas protective cover is installed around the laser welding head and includes a cover body and gas nozzles. The cover body has a cover-like structure and surrounds the focusing lens group of the laser welding head. The gas nozzles are located inside the cover body and are connected to the argon gas supply device through a gas pipeline. The gas nozzles spray argon gas into the welding area to form an inert gas protective layer.

[0016] This invention employs an innovative workbench system structure. Multiple separate floating platform plates are arranged along the welding direction with expansion gaps between them. Each separate floating platform plate is slidably supported on a base frame via a linear guide assembly. The clamping unit presses and fixes the workpiece to the separate floating platform plates instead of directly fixing it to the rigid base frame, forming an integral unit between the workpiece and the separate floating platform plates. The thermal expansion displacement of the workpiece is directly transferred to the separate floating platform plates without overcoming the frictional resistance between the workpiece and the platform surface. This eliminates the constraint effect of frictional resistance on thermal expansion, keeping the workpiece's position relative to the separate floating platform plates constant. This ensures consistent butt joint gaps throughout the weld seam, solving the technical problem of inconsistent weld width caused by accumulated thermal expansion in laser welding of large-size titanium alloy thin plates, and achieving the technical effect of improving the uniformity of welding quality. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a laser welding equipment for titanium alloy thin plates according to the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of a laser welding equipment for titanium alloy thin plates according to the present invention. Figure 2 ; Figure 3 This is a schematic diagram of the structure of a laser welding equipment for titanium alloy thin plates according to the present invention. Figure 3 ; Figure 4 This is a schematic diagram of the structure of a laser welding equipment for titanium alloy thin plates according to the present invention. Figure 4 ; Figure 5 This is a schematic diagram of the structure of a laser welding equipment for titanium alloy thin plates according to the present invention. Figure 5 ; Detailed Implementation

[0018] In laser welding applications of titanium alloy thin plates, the equipment uses a fixture system to fix the workpiece to be welded on the worktable, and the laser beam moves along a predetermined trajectory to complete the welding. During the welding process, the fixture needs to withstand the thermal expansion stress generated by the heat input of the workpiece.

[0019] For large-format titanium alloy sheets exceeding ten meters in length, the welding thermal cycle causes cumulative thermal expansion along the workpiece's length. Existing technology employs a rigid worktable, on which the workpiece is placed and fixed by a fixture. The rigid worktable itself does not deform with the workpiece. The fixed support provided by the rigid worktable leads to relative sliding friction between the workpiece and the rigid worktable when the workpiece shifts due to thermal expansion. This sliding friction hinders the workpiece's free expansion, causing a shift in the butt joint gap in the later stages of the weld. As the welding process progresses, the positional deviation between the cumulative thermal expansion and the fixture constraint points gradually increases, resulting in inconsistent weld width and affecting the uniformity of the overall weld quality.

[0020] like Figure 1-5 As shown in the embodiment, a titanium alloy thin plate laser welding equipment is provided, including a laser system 1, a motion system, a worktable system, a clamping system, a protective gas system, and a control system.

[0021] Laser system 1 includes a laser generator and a laser welding head. The laser generator is used to generate a high-energy laser beam. The laser welding head is connected to the laser generator via an optical fiber, which transmits the laser beam from the laser generator to the laser welding head. The laser welding head is equipped with a focusing lens group, which focuses the laser beam onto the welding point.

[0022] The motion system includes a gantry 2 and a drive mechanism. The gantry 2 spans above the worktable system and includes two columns and a crossbeam connecting the tops of the two columns. The laser welding head is mounted on the crossbeam via a slide block, which is connected to the crossbeam by a linear guide rail, allowing the laser welding head to move along the length of the crossbeam. The drive mechanism includes a transverse drive unit and a longitudinal drive unit. The transverse drive unit drives the laser welding head to move along the crossbeam, and the longitudinal drive unit drives the gantry 2 to move perpendicular to the crossbeam. The cooperation of the transverse and longitudinal drive units achieves two-dimensional planar motion of the laser welding head in the horizontal plane.

[0023] In some embodiments, the lateral drive unit is a rack and pinion transmission mechanism, with the rack fixed to the crossbeam and extending along its length, the gear mounted on the slide and meshing with the rack, the gear being driven to rotate by a servo motor, and the precise movement of the slide along the crossbeam achieved through the meshing transmission of the rack and pinion.

[0024] In some embodiments, the longitudinal drive unit is a ball screw 5 transmission mechanism. The ball screw 5 is arranged in a direction perpendicular to the crossbeam. The nut seat of the ball screw 5 is fixedly connected to the column of the gantry 2. The ball screw 5 is driven to rotate by a servo motor. The gantry 2 moves longitudinally through the helical transmission between the ball screw 5 and the nut seat.

[0025] The workbench system includes a basic frame, multiple separate floating platform 3, and a linear guide assembly.

[0026] The basic frame is a rigid support structure, which includes a bottom support frame and a perimeter vertical frame. The bottom support frame is made of welded steel sections, and the perimeter vertical frame is fixed to the perimeter of the bottom support frame and extends upward.

[0027] The split floating platforms 3 are arranged along the length of the base frame, with expansion gaps between each split floating platform 3. Each split floating platform 3 includes a platform body and a bottom fixing seat. The platform body is a flat plate structure, with the upper surface of the platform body serving as a flat workpiece support surface, and the bottom fixing seat is fixed to the lower surface of the platform body.

[0028] Furthermore, the width of the expansion gap between each split floating platform 3 is set to five to twenty millimeters. The width of the expansion gap is determined according to the length of the workpiece and the expected amount of thermal expansion. The expansion gap is used to absorb the relative displacement of adjacent split floating platforms 3 caused by the thermal expansion of the workpiece.

[0029] Linear guide assemblies are used to slidably support the split floating platform 3 on the base frame. Each split floating platform 3 is supported by at least two sets of linear guide assemblies. Each set of linear guide assemblies includes a guide post 7 and a linear bearing. The linear bearing is fixed to the bottom support frame of the base frame. The guide post 7 is arranged along the welding direction. The first end of the guide post 7 is fixed to the bottom fixing seat of the platform. The guide post 7 passes through the linear bearing. The inner ring of the linear bearing forms a sliding fit with the outer surface of the guide post 7. The guide post 7 can slide freely relative to the linear bearing along its axial direction.

[0030] A spring is provided on the guide column 7 to balance the weight of the floating platform 3 and prevent it from moving downwards due to its own weight.

[0031] In some embodiments, the linear bearing is a linear ball bearing with a sealing structure. The linear ball bearing has multiple ball cages within it, and the balls circulate axially within the cages. The rolling contact of the balls reduces the frictional resistance between the guide post 7 and the linear bearing. Sealing structures are located at both ends of the linear ball bearing, preventing dust and welding spatter from entering the bearing.

[0032] Furthermore, in order to improve the guiding accuracy, each split floating platform 3 is equipped with four sets of linear guide components. The four sets of linear guide components are respectively set at the four corners of the fixed base at the bottom of the platform. The axes of the four guide columns 7 are parallel to each other and are all set along the welding direction.

[0033] The first platform is the positioning reference platform 4. No linear guide components are installed between the positioning reference platform 4 and the base frame. The bottom fixing seat of the positioning reference platform 4 is directly fixed to the bottom support frame of the base frame with bolts. The positioning reference platform 4 maintains its position during welding, serving as the positioning reference for the workpiece. All other platforms besides the positioning reference platform 4 are split-type floating platforms 3. These split-type floating platforms 3 are supported by linear guide components and can float freely along the welding direction.

[0034] Furthermore, the upper surface of the positioning reference plate 4 is provided with positioning components, including a longitudinal positioning block and a transverse positioning block. The longitudinal positioning block is fixed to the front edge of the positioning reference plate 4 and perpendicular to the workpiece placement direction, and is used to limit the longitudinal starting position of the workpiece. The transverse positioning block is fixed to the side edge of the positioning reference plate 4 and parallel to the workpiece placement direction, and is used to limit the transverse offset of the workpiece. When the workpiece is placed, its head abuts against the longitudinal positioning block and its side abuts against the transverse positioning block. The accurate positioning of the workpiece is achieved through the cooperation of the longitudinal positioning block and the transverse positioning block.

[0035] In some embodiments, in order to limit the maximum floating distance of the split floating platform 3, a limiting protrusion is provided on the fixed base at the bottom of the platform, and a limiting elongated hole is provided at the corresponding position on the bottom support frame of the base frame. The limiting protrusion passes through the limiting elongated hole, which extends along the welding direction. The length of the limiting elongated hole is greater than the outer diameter of the limiting protrusion. When the split floating platform 3 floats to the point where the end of the limiting protrusion contacts the end of the limiting elongated hole, the limiting protrusion prevents the split floating platform 3 from continuing to move. The floating stroke of the split floating platform 3 is limited by the cooperation between the limiting protrusion and the limiting elongated hole.

[0036] The clamping system includes multiple clamping units 6, each mounted on a corresponding split-type floating platform 3. Each clamping unit 6 includes a clamping base, a clamping mechanism, and a driving device. The clamping base is fixed to the upper surface of the split-type floating platform 3. The clamping mechanism is hinged to the clamping base via a rotating shaft. The clamping mechanism includes a clamping arm and a pressure plate. The first end of the clamping arm is hinged to the clamping base via a rotating shaft, and the second end of the clamping arm is fixedly connected to the pressure plate. The lower surface of the pressure plate is the workpiece contact surface. The driving device drives the clamping mechanism to rotate around the rotating shaft, switching the pressure plate between a raised position and a clamping position. When the pressure plate is in the clamping position, it clamps and fixes the workpiece to the upper surface of the split-type floating platform 3.

[0037] In some embodiments, the driving device is a pneumatic cylinder, the cylinder body of which is hinged to the fixture base, and the piston rod end of which is hinged to the clamping arm. The extension and retraction of the pneumatic cylinder drives the clamping arm to rotate around the pivot.

[0038] Furthermore, to prevent the workpiece from slipping while clamped, an anti-slip layer is provided on the lower surface of the pressure plate where it contacts the workpiece. The anti-slip layer is made of rubber or has a toothed structure, which increases the coefficient of friction between the pressure plate and the workpiece.

[0039] The protective gas system includes an argon supply device and a gas protective hood. The argon supply device includes an argon storage tank, a pressure regulating valve, and a gas delivery pipeline. The argon storage tank stores high-pressure argon, the pressure regulating valve is connected to the outlet of the argon storage tank, and the gas delivery pipeline connects the pressure regulating valve to the gas protective hood. The gas protective hood is installed around the laser welding head and includes a hood body and gas nozzles 8. The hood body has a hood-like structure and surrounds the focusing lens assembly of the laser welding head. The lower opening of the hood body faces the workpiece surface. The gas nozzles 8 are located inside the hood body and connected to the gas delivery pipeline. The argon supply device supplies argon to the gas protective hood through the gas delivery pipeline. After the argon is ejected from the gas nozzles 8, it forms an inert gas protective layer in the welding area. This inert gas protective layer isolates the welding area from air, preventing oxidation of the titanium alloy during high-temperature welding.

[0040] In some embodiments, the gas protective cover includes a back protection chamber, which is located below the worktable system at a position corresponding to the weld. The back protection chamber includes a cavity and a sealing edge. The cavity has a groove-shaped structure with the opening facing upwards. The sealing edge is located at the upper edge of the cavity and contacts the lower surface of the workpiece. The back protection chamber is connected to an argon gas supply device through a connecting pipeline. After the argon gas enters the back protection chamber, it forms an inert gas protection for the back of the weld.

[0041] Furthermore, the back protective chamber corresponding to the split floating platform 3 is fixedly installed on the lower surface of the bottom fixing seat of the split floating platform 3. The back protective chamber moves synchronously with the split floating platform 3, thereby maintaining stable contact between the sealing edge and the lower surface of the workpiece and avoiding sealing failure due to displacement of the split floating platform 3. The back protective chamber corresponding to the positioning reference platform 4 is fixedly installed on the bottom support frame of the base frame. Since the position of the positioning reference platform 4 is fixed, the relative position of the back protective chamber corresponding to the positioning reference platform 4 and the workpiece remains unchanged.

[0042] Furthermore, the connecting pipe to the rear protective chamber corresponding to the split floating platform 3 is a flexible hose. One end of the flexible hose is connected to the air inlet of the rear protective chamber, and the other end of the flexible hose is connected to the gas supply main pipe fixed on the base frame. The flexible hose has sufficient length and bending allowance to accommodate the displacement of the split floating platform 3 along the linear guide assembly during the welding process, ensuring that the gas supply is not affected when the split floating platform 3 moves.

[0043] Furthermore, in order to improve the replacement efficiency of the back protective gas, a guide plate is provided in the back protective chamber. The guide plate extends along the welding direction and divides the space in the chamber into an inlet channel and an exhaust channel. Argon gas enters from the inlet channel and flows along the weld direction to the far end, and then exits through the exhaust channel. The guide plate makes the argon gas form a directional flow path in the chamber, which accelerates the discharge speed of residual air.

[0044] The control system includes a main control unit and a human-machine interface (HMI). The main control unit is a programmable logic controller (PLC), which is electrically connected to the laser generator, the drive mechanism, the drive unit of the clamping system, and the pressure regulating valve of the protective gas system. The HMI is a touch screen, which is communicatively connected to the main control unit. The main control unit receives welding parameters input by the operator through the HMI, including laser power, welding speed, and welding trajectory. Based on these parameters, the main control unit controls the laser generator to output a laser beam of corresponding power and controls the drive mechanism to move the laser welding head according to the welding trajectory and welding speed.

[0045] According to an embodiment of this invention, the use of a laser welding equipment for titanium alloy thin plates includes the following steps.

[0046] The titanium alloy sheet workpiece is placed on the worktable system. The workpiece spans the upper surface of each split floating platform 3. The head end of the workpiece abuts against the longitudinal positioning block on the positioning reference platform 4, and the side of the workpiece abuts against the transverse positioning block. The initial positioning of the workpiece is completed by the positioning components.

[0047] The workpiece is clamped and fixed in sections by each clamping unit 6. The operator starts the drive device of each clamping unit 6. The drive device drives the clamping mechanism to move, and the pressure plate presses down to the upper surface of the workpiece, clamping and fixing the workpiece on the corresponding split floating platform 3. The workpiece section on each split floating platform 3 is independently clamped by the corresponding clamping unit 6.

[0048] Welding parameters, including laser power, welding speed, and welding trajectory, are set through a human-machine interface. The main control unit receives and stores the welding parameters.

[0049] The protective gas system is activated, and the main control unit controls the pressure regulating valve of the argon gas supply device to open. Argon gas is supplied to the gas protective cover through the gas pipeline, and the gas protective cover sprays argon gas into the welding area to form an inert gas protective layer.

[0050] In some embodiments, activating the protective gas system further includes activating the gas supply to the back protection chamber. Argon gas enters the back protection chamber and then exhausts the air inside the chamber. When the oxygen content in the back protection chamber drops below a preset threshold, the back protection preparation is completed.

[0051] The laser generator is activated, producing a high-energy laser beam. This beam is transmitted through an optical fiber to the laser welding head and focused by a focusing lens group. The main control unit controls the drive mechanism to move the laser welding head to the welding start position, which is the starting point of the welding trajectory.

[0052] The laser welding head moves along a predetermined welding trajectory to perform welding. The main control unit controls the drive mechanism according to the welding parameters. The drive mechanism drives the laser welding head to move along the welding trajectory at a set welding speed. The focused laser beam irradiates the workpiece surface, melting the material in the mating area and forming a molten pool. After the molten pool cools and solidifies, it forms a weld. The protective gas hood moves synchronously with the laser welding head, continuously supplying argon gas to the welding area.

[0053] In some embodiments, the welding process includes a welding initiation stage, a welding stabilization stage, and a welding termination stage. The welding initiation stage uses a lower laser power and a slower welding speed to establish a stable molten pool. The welding stabilization stage uses normal welding parameters for continuous welding. The welding termination stage gradually reduces the laser power and slows down the welding speed to avoid welding termination defects. The main control unit automatically switches the welding parameters for different stages according to the position of the laser welding head.

[0054] During welding, the workpiece undergoes thermal expansion due to the laser heat input. This thermal expansion accumulates along the welding direction, causing the split-type floating platform 3 beneath it to move synchronously along the linear guide assembly. Since the fixture unit 6 presses and fixes the workpiece onto the split-type floating platform 3, the workpiece and the platform form a single unit. The platform 3 can slide freely along the welding direction through the sliding fit between the guide post 7 of the linear guide assembly and the linear bearing. The displacement generated by the workpiece's thermal expansion is directly transmitted to the platform 3, with no relative sliding between them. The expansion gap between each split-type floating platform 3 absorbs the relative displacement of adjacent platforms, and the width of the expansion gap dynamically changes with the displacement of the platform 3.

[0055] In some embodiments, the welding process further includes a step of real-time monitoring of workpiece deformation. A displacement sensor is set on the worktable system. The displacement sensor detects the displacement of the split floating platform 3. The main control unit receives the signal from the displacement sensor and determines the thermal expansion state of the workpiece. When the displacement of the split floating platform 3 exceeds a preset range, the main control unit issues an alarm to prompt the operator to check.

[0056] After welding is completed, the laser generator is turned off, and the laser beam stops outputting. The shielding gas system continues to operate, with argon gas continuously supplied to the welding area to provide inert gas protection for the high-temperature weld until it cools to a safe temperature. The main control unit controls the operating time of the shielding gas system according to the preset cooling time.

[0057] Release each clamping unit 6, and the main control unit controls the drive device of each clamping unit 6 to reverse the action, and the pressure plate of the clamping mechanism lifts up to release the clamping force on the workpiece. During the cooling process, the workpiece shrinks, and each split floating platform 3 slides back to its initial position along the linear guide assembly as the workpiece shrinks, and the expansion and contraction gap between each split floating platform 3 returns to its initial width.

[0058] After the welding is completed, the operator removes the workpiece from the workbench system for further processing.

[0059] According to an embodiment of this invention, the titanium alloy thin plate laser welding equipment adopts an innovative structure of a worktable system, which includes a basic frame, multiple split floating table plates 3, and a linear guide assembly.

[0060] Because the workbench system adopts a split floating platform 3 structure, multiple split floating platforms 3 are arranged along the length direction, and there is a telescopic gap between each split floating platform 3. Each split floating platform 3 is slidably supported on the base frame through a linear guide component. Therefore, each split floating platform 3 can float independently without interfering with each other.

[0061] Since the clamping unit 6 of the clamping system presses and fixes the workpiece to the split floating platform 3 instead of directly fixing it to the rigid base frame, the workpiece and the split floating platform 3 form an integral unit. Therefore, the thermal expansion displacement of the workpiece can be directly transmitted to the split floating platform 3 without overcoming the frictional resistance between the workpiece and the platform.

[0062] Since the split floating platform 3 can slide freely along the welding direction through the sliding fit between the guide column 7 of the linear guide assembly and the linear bearing, the sliding friction resistance of the guide column 7 relative to the linear bearing is much smaller than the sliding friction resistance between the workpiece and the rigid platform. Therefore, when the workpiece thermal expansion drives the split floating platform 3 to move synchronously, it is not hindered by significant friction resistance, thus eliminating the constraint effect of friction resistance on thermal expansion.

[0063] Since each of the separate floating platforms 3 is independent of each other and there is a telescopic gap between them, the displacement of each separate floating platform 3 does not affect each other. The telescopic gap absorbs the relative displacement of adjacent separate floating platforms 3 caused by the thermal expansion of the workpiece. Therefore, the cumulative transmission of thermal expansion stress between the platforms is avoided. The thermal expansion of the workpiece section on each separate floating platform 3 is released independently within its section.

[0064] Since the workpiece and the split floating platform 3 move synchronously as a whole unit, there is no relative sliding between the workpiece and the split floating platform 3. The position of the workpiece relative to the split floating platform 3 remains unchanged. Therefore, the butt joint gap of the workpiece remains stable relative to the split floating platform 3, and the butt joint gap remains consistent throughout the entire length of the weld.

[0065] Because the butt gap remains consistent throughout the entire weld length, the width and depth of the molten pool at each location remain stable during laser welding. Therefore, the weld formation width remains consistent along the welding direction, ensuring the uniformity of the overall plate welding quality and solving the problem of inconsistent weld formation caused by accumulated thermal expansion in the laser welding of large-size titanium alloy thin plates.

[0066] In addition, because the protective gas system supplies argon gas to the welding area to form an inert gas protective layer, the inert gas protective layer isolates the welding area from the air, thus effectively preventing the oxidation reaction of titanium alloy during high-temperature welding and ensuring the quality and mechanical properties of the weld joint.

Claims

1. A titanium alloy sheet laser welding apparatus characterized by comprising: The application relates to a laser welding system. The laser system comprises a laser generator and a laser welding head, the laser generator is used for generating a laser beam, the laser welding head is connected with the laser generator through an optical fiber, and a focusing lens group is arranged in the laser welding head. The motion system comprises a portal frame and a driving mechanism, the portal frame is arranged above the workbench system, the laser welding head is installed on a crossbeam of the portal frame through a sliding seat, and the driving mechanism drives the laser welding head to move in a horizontal plane. The workbench system comprises a base frame, a plurality of split floating platform plates and linear guide assemblies, the split floating platform plates are arranged along a welding direction, an expansion gap is left between the split floating platform plates, the linear guide assemblies are used for slidably supporting the split floating platform plates on the base frame, and each split floating platform plate is supported through at least two groups of linear guide assemblies. The clamping system comprises a plurality of clamping units, each clamping unit is installed on a corresponding split floating platform plate, and the clamping unit tightly fixes a workpiece on the upper surface of the split floating platform plate. The linear guide assembly comprises a guide shaft and a linear bearing, the linear bearing is fixed on the base frame, the guide shaft is arranged along the welding direction, the first end of the guide shaft is fixed on the split floating platform plate, and the guide shaft penetrates through the linear bearing and can freely slide along the axial direction of the linear bearing.

2. The titanium alloy sheet laser welding apparatus of claim 1, wherein, The base frame comprises a bottom support frame and a peripheral standing edge frame, the bottom support frame is composed of profile steel welding, and the peripheral standing edge frame is fixed on the periphery of the bottom support frame and extends upwards.

3. The titanium alloy sheet laser welding apparatus of claim 1, wherein, The width of the expansion gap between the split floating platform plates is 5-20 mm, and the expansion gap is used for absorbing the relative displacement of adjacent split floating platform plates caused by the thermal expansion of the workpiece.

4. The titanium alloy sheet laser welding apparatus of claim 1, wherein, The split floating platform plate comprises a platform body and a platform bottom fixing seat, the upper surface of the platform body is a workpiece support surface, the platform bottom fixing seat is fixed on the lower surface of the platform body, and the first end of the guide shaft is fixed on the platform bottom fixing seat.

5. The titanium alloy sheet laser welding apparatus of claim 1, wherein, The linear bearing is a linear ball bearing with a sealing structure, a plurality of ball retainers are arranged in the linear ball bearing, balls circulate and roll in the ball retainers along the axial direction, and the sealing structure is arranged at both ends of the linear ball bearing.

6. The titanium alloy sheet laser welding apparatus of claim 1, wherein, Each split floating platform plate is provided with four groups of linear guide assemblies, the four groups of linear guide assemblies are arranged at four corner positions of the split floating platform plate, and the axes of the four guide shafts are parallel to each other and arranged along the welding direction.

7. The titanium alloy sheet laser welding apparatus of claim 1, wherein, The first split floating platform is a positioning reference platform, which is directly fixed to the base frame through bolts, and the upper surface of the positioning reference platform is provided with positioning members, which include longitudinal positioning blocks and transverse positioning blocks, the longitudinal positioning blocks are fixed to the front end edges of the positioning reference platform and are perpendicular to the placement direction of the workpiece, and the transverse positioning blocks are fixed to the side edges of the positioning reference platform and are parallel to the placement direction of the workpiece.

8. The titanium alloy sheet laser welding apparatus of claim 1, wherein, The clamp unit includes a clamp base, a pressing mechanism and a driving device, the clamp base is fixed to the upper surface of the split floating platform, the pressing mechanism is hinged to the clamp base through a rotating shaft, the pressing mechanism includes a pressing arm and a pressing plate, the first end of the pressing arm is hingedly connected with the clamp base through the rotating shaft, the second end of the pressing arm is fixedly connected with the pressing plate, and the driving device drives the pressing mechanism to rotate around the rotating shaft, so that the pressing plate is switched between a lifting position and a pressing position.

9. The titanium alloy sheet laser welding apparatus of claim 8, wherein, The driving device is a pneumatic cylinder, the cylinder body of the pneumatic cylinder is hinged to the clamp base, the piston rod end of the pneumatic cylinder is hinged to the pressing arm, and the lower surface of the pressing plate is provided with an anti-skid layer.

10. The titanium alloy sheet laser welding apparatus of claim 1, wherein, It also includes a protective gas system, which includes an argon gas supply device and a gas protection cover, the gas protection cover is installed around the laser welding head, the gas protection cover includes a cover body and a gas nozzle, the cover body is in a cover-shaped structure and surrounds the focusing lens group of the laser welding head, the gas nozzle is arranged in the cover body and communicates with the argon gas supply device through a gas pipeline, and the gas nozzle sprays argon to the welding area to form an inert gas protection layer.

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