Laser welding clamping and rotating device for embedded weld joint in narrow space

Abstract

The invention discloses a clamping and rotating device for laser welding of an embedded weld joint in a narrow space, and belongs to the technical field of laser welding tools. The device comprises a rigid cross beam, a front-end flange plate, a rear-end flange plate, at least two fixed rotary discs, a tensioning pull rod and two rotary driving interfaces arranged on the outer sides of the flange plates. Through the combination of the split type fixed turntable and the tensioning pull rod, the workpiece can be quickly and rigidly supported from the inside; the flange plates arranged at the two ends provide axial jacking and radial positioning; and one of the rotary driving interfaces at the two ends can be selected to be connected with an external positioner, and the posture of a workpiece can be adjusted by matching with a height-adjustable supporting mechanism, so that the circle center of any embedded circumferential weld is coaxial with a rotating shaft of the positioner. The technical problems that due to the fact that movement of the laser head in a narrow space is limited, the embedded circumferential weld cannot be integrally formed at a time, the welding quality is poor, and the efficiency is low are solved, and the method is particularly suitable for welding of the embedded circumferential weld with the two ends not coaxial.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser welding tooling, in particular to a laser welding clamping and rotating device for embedded welds in a narrow space. BACKGROUND

[0002] With the increasing demand for lightweight products in the field of aerospace and other fields, the double-layer design is often used for cabin body structure, thereby forming an embedded ring weld inside the cylindrical component. The operation space of such a weld is extremely narrow, resulting in poor accessibility of the laser welding head and making it impossible to perform conventional motion welding.

[0003] In the prior art, for such embedded ring welds, manual segmented welding or simple tooling is often used. Manual segmented welding has problems such as excessive joints, uneven quality, large deformation, low efficiency, etc. caused by multiple arc striking and arc collecting. And the ordinary welding tooling is difficult to realize high rigidity, high precision positioning and stable rotation of the workpiece in a narrow space. Especially when welding two embedded double-ring welds that are not coaxial, the existing tooling is difficult to complete the welding of the two welds in turn through simple operation after one clamping, often requiring a complex disassembly and repositioning process, not only low efficiency, but also difficult to guarantee the concentricity and welding stability of the two welds, which seriously restricts the product quality and production efficiency.

[0004] Therefore, there is an urgent need for a laser welding tooling specially used for embedded welds in a narrow space, which can realize high-rigidity clamping and precise rotation, and can efficiently and qualitatively handle non-coaxial double-ring welds. SUMMARY

[0005] In view of the deficiencies of the prior art, the embodiments of the present application aim to provide a laser welding clamping and rotating device for embedded welds in a narrow space, to at least solve one of the technical problems that the workpiece clamping rigidity is insufficient, the rotation accuracy is not high, and non-coaxial double-ring welds cannot be efficiently handled when welding embedded welds in the prior art.

[0006] In one aspect, the embodiments of the present application provide a clamping and rotating device for laser welding of embedded ring welds, comprising:

[0007] a rigid crossbeam, which axially passes through the inside of the cylindrical workpiece to be welded in sequence;

[0008] a front flange plate and a rear flange plate, respectively fixed to the two ends of the crossbeam, for axially clamping and radially positioning the workpiece from both ends of the workpiece;

[0009] at least two fixed rotating discs, which are fixed to the crossbeam through support blocks and located inside the workpiece, for internally supporting the workpiece to enhance its rigidity and transmit torque;

[0010] Two rotary drive interfaces are arranged on the outer sides of the front flange plate and the rear flange plate respectively, and are used for selectively connecting with an external positioner;

[0011] In addition, a supporting mechanism corresponding to the fixed rotary disc is arranged below the fixed rotary disc, and is used for supporting the fixed rotary disc and supporting the whole device on a work platform.

[0012] Further, the front flange plate and the rear flange plate are provided with a clamping bolt for axially clamping a workpiece and a positioning pin for radial limiting.

[0013] Further, the fixed rotary disc is of a split structure, and comprises an upper half and a lower half, and is fixed as a whole through a bolt.

[0014] Further, the at least two fixed rotary discs are connected and reinforced through at least one tensioning pull rod distributed in a circumferential direction.

[0015] Further, the rotary drive interface is a hexagonal chuck, a square chuck or a spline chuck.

[0016] Further, the supporting mechanism is a height-adjustable roller bracket.

[0017] Further, the support block and the cross beam are detachably connected.

[0018] Further, a first lifting hole for overall lifting is arranged on the device.

[0019] Further, the first lifting hole is arranged on the front flange plate and / or the rear flange plate.

[0020] In another aspect, the present application provides a welding method using the above-mentioned clamping rotary device, and comprises the following steps:

[0021] S1. Clamping: fixing a workpiece having two non-coaxial embedded circumferential welds on a welding tool, and the tool is provided with a drive interface capable of being connected with a positioner at both ends;

[0022] S2. First weld welding: connecting the first drive interface of the tool with the positioner, adjusting the position of the positioner to make the center of the first circumferential weld coaxial with the rotating shaft of the positioner, starting the positioner and the laser welder, and completing the overall one-time welding of the first circumferential weld;

[0023] S3. Tool transformation: disconnecting the first end of the tool from the positioner, and transforming the position of the tool as a whole to connect the second drive interface of the tool with the positioner;

[0024] S4. Second weld: Adjust the positioner so that the center of the second circumferential weld is coaxial with the rotation axis of the positioner. Start the positioner and laser welding machine to complete the overall one-time welding of the second circumferential weld.

[0025] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0026] 1) This invention utilizes rotary drive interfaces (such as hexagonal chucks) located at both ends of the workpiece, combined with the overall turning design of the tooling, to achieve the sequential welding of two non-coaxial embedded circumferential welds after a single clamping and fixing. This avoids the cumbersome operations of multiple adjustments to the welding position required due to the concealed location of the welds in traditional methods, reduces auxiliary time, and significantly improves welding efficiency, making it particularly suitable for mass production.

[0027] 2) This invention utilizes a high-rigidity main frame composed of a rigid crossbeam, a split-type fixed turntable, and circumferentially distributed tension rods. This structure ensures that the workpiece does not shift or deform during rotary welding, providing a stable motion reference for laser welding. It solves defects such as uneven weld formation and incomplete fusion caused by workpiece vibration or displacement, laying a solid foundation for obtaining high-precision, high-quality continuous circumferential welds.

[0028] 3) The split-type fixed turntable design of the tooling of this invention facilitates the loading and unloading of workpieces; the lifting holes on the flange facilitate the hoisting and 180° turning operations of the tooling; and the height-adjustable support mechanism can adapt to welds with different axes, aligning them with the rotating shaft of the positioner. These designs together improve the overall versatility and on-site operability of the tooling, reducing the labor intensity of workers.

[0029] 4) The method of the present invention, through scraping and cleaning → tack welding → coaxial alignment → rotary welding → turning welding, this systematic process route, and in synergy with special welding tooling, ensures quality control throughout the entire process from pre-welding pretreatment to final forming, eliminates segmented welding caused by space constraints, eliminates welding defects (such as arc craters, cracks, etc.) caused by multiple arc starting and extinguishing, and realizes high-quality one-time continuous welding of embedded circumferential welds.

[0030] 5) The method of the present application, by the accurate coaxial alignment step (during the clamping process, by adjusting the height of the positioner to keep the center of the embedded girth weld coaxial with the rotating shaft, and cooperating with the positioning and support of the front and rear flanges and the roller bracket, to ensure the coaxiality of the workpiece during the rotary welding process), ensures the constant welding line speed, combined with the specific welding parameter combination optimized for 3-5mm thick aluminum alloy (such as laser power 1900W-2300W, welding speed 0.007m / s-0.011m / s, etc.), which can obtain a high-quality weld with uniform penetration, no pores and no incomplete fusion, and the tensile strength can reach more than 91% of the base material.

[0031] 6) The method of the present application: the welding sequence of welding one end → turning the whole 180° → welding the other end, clear logic, simple operation, efficiently solves the process problem of welding two non-coaxial embedded welds on the same workpiece, and the whole welding can be completed by one clamping and simple station transformation, not only safe and convenient operation, but also ensures the consistency of the quality of the double welds, and improves the overall manufacturing efficiency and reliability.

[0032] In the present application, the above technical solutions can be combined with each other to realize more preferred combination schemes. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification, or will be understood by implementing the present application. The purpose and other advantages of the present application can be realized and obtained from the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0034] Figure 1 It is a schematic diagram of the overall structure of the laser welding clamping rotary device of the present application;

[0035] Figure 1a It is a schematic diagram of the weld of the laser welding clamping rotary device of the present application in the state of clamping the workpiece to be welded;

[0036] Figure 2 It is a front view of the laser welding clamping rotary device of the present application;

[0037] Figure 3 It is a side view of the laser welding clamping rotary device of the present application;

[0038] Figure 4 It is Figure 3 It is a schematic diagram of the structure after disassembling the base.

[0039] Reference signs:

[0040] 1, front flange plate; 2, rear flange plate; 3, positioning pin; 4, first fixed rotating disc; 5, second fixed rotating disc; 6, support block; 7, tensioning pull rod; 8, cross beam; 9, first supporting mechanism; 10, second supporting mechanism; 11, first driving interface; 12, second driving interface; 13, first base; 14, second base; 15, first lifting hole; 16, second lifting hole; 17, third lifting hole; 18, weld. DETAILED DESCRIPTION

[0041] The preferred embodiments of the present application will be described in detail below with reference to the drawings, wherein the drawings constitute a part of this application and serve to explain the principles of the embodiments of the present application, but are not intended to limit the scope of the present application.

[0042] With the development of aircraft products towards lightweight and compact structure, the adoption of design concepts such as double-layer structure installation has resulted in the emergence of embedded weld structures inside the cabin. Such welds are located inside the narrow cylindrical space, with poor accessibility, and the traditional laser welding equipment cannot achieve overall one-time welding, often requiring segmented welding, which leads to unstable weld quality, low efficiency, and problems such as welding deformation and arc extinguishing defects. The present application aims to provide a special clamping rotary device and welding method to solve the overall laser welding problem of non-coaxial embedded girth welds.

[0043] In one aspect, a specific embodiment of the present application discloses a clamping rotary device for laser welding of embedded girth welds, as shown in Figures 1-4 The device comprises: a rigid cross beam which axially passes through the inside of the cylindrical workpiece to be welded (the cross beam is the core load-bearing component of the entire device, penetrating the workpiece and various functional components);

[0044] Front and rear flange plates are fixed to the two ends of the cross beam respectively (preferably symmetrically distributed at the two ends of the cross beam axis), used for axially clamping and radially positioning the workpiece from both ends;

[0045] At least two fixed rotating discs (first fixed rotating disc, second fixed rotating disc) are fixed to the cross beam through support blocks and located inside the workpiece (the fixed rotating disc is attached to the inner surface of the workpiece cylinder wall), used for internally supporting the workpiece to enhance its rigidity and transmit torque;

[0046] Two rotary driving interfaces (first driving interface, second driving interface) are respectively arranged on the outer side of the front flange plate and the rear flange plate (the protruding structure on the outer end of the middle flange plate), used for selectively driving connection with the external positioner; Figure 1

[0047] ​And, a support mechanism (a bearing component) corresponding to the fixed turntable is arranged below the fixed turntable, and is used for supporting the fixed turntable and supporting the whole device on a working platform.

[0048] The device provides a stable and accurate rotating support platform for the girth weld embedded in the cylindrical workpiece, so that the laser head can be fixed, and the workpiece can rotate as a whole, thereby realizing continuous and overall one-time welding of the girth weld. Figure 1a As shown, after the workpiece to be welded is assembled in the device, the girth weld is located in the tooling area formed by the support and rotating mechanism, thereby ensuring accurate implementation of laser welding.

[0049] In implementation, first, the workpiece to be welded (such as a cylindrical workpiece and an end frame assembly) is sequentially subjected to pretreatment such as cleaning, trial assembly, scraping and cleaning, and positioning welding.

[0050] Subsequently, the assembled workpiece is sleeved on the cross beam, and the workpiece is subjected to axial clamping and radial limiting by the clamping bolts and the positioning pins on the front flange plate and the rear flange plate, respectively, to avoid movement of the workpiece during welding. Figure 2 As shown, the positioning pins protrude radially along the flange plate and are accurately matched with the prefabricated positioning holes of the end frame of the workpiece, thereby ensuring coaxiality of the workpiece and the cross beam.

[0051] Then, the lower half of the first fixed turntable and the second fixed turntable is preassembled on the cross beam by a support block: the support block extends radially along the cross beam (the radial dimension of the support block is matched with the inner circumferential wall of the fixed turntable), the outer end surface of the support block is matched with the inner circumferential wall of the fixed turntable, and the fixed turntable and the support block are fixed by bolts; the upper half of the fixed turntable is folded and fastened by bolts, at this time, the outer circumferential wall of the fixed turntable is matched with the inner surface of the workpiece cylinder wall (no gap is formed between the two), and the workpiece is radially clamped from the inside by interference fit or uniformly distributed clamping screws (integrated in the fixed turntable body) abutting against the inner surface of the workpiece cylinder wall.

[0052] Meanwhile, at least two (four in the drawing) tensioning rods are arranged axially along the cross beam, the two ends of the tensioning rods pass through the through holes corresponding to the first fixed turntable and the second fixed turntable, respectively, and the two ends of the tensioning rods are screwed by nuts, so that the two fixed turntables are axially tensioned and form a rigid whole, thereby uniformly transmitting torque and inhibiting radial deformation of the fixed turntable.

[0053] Then, the fixed turntable is supported by a support mechanism: the support mechanism is a height-adjustable roller bracket, and an arc-shaped roller set matched with the outer circumferential wall of the fixed turntable is arranged on the top of the support mechanism. Figure 4As shown, the arc-shaped roller group is consistent with the arc of the lower half of the fixed turntable, and the arc surface of the arc-shaped roller group is in rolling contact with the outer peripheral wall of the lower half of the fixed turntable; by adjusting the lifting screw at the bottom of the supporting mechanism, the supporting surface of the arc-shaped roller group is kept horizontal with the axis of the fixed turntable, so as to stably support the fixed turntable and the whole device on the working platform.

[0054] Finally, according to the position of the welding seam to be welded, the first driving interface on the outside of the front flange plate or the second driving interface on the outside of the rear flange plate is connected with the external positioner, the whole tooling and workpiece are driven to rotate synchronously by the positioner, and the laser head fixedly arranged is used to complete the girth weld welding.

[0055] Compared with the prior art, the clamping rotary device provided by the embodiment constructs a high-rigidity rotary body for the cylindrical workpiece through the combined mode of "internal fixed turntable straining + flange plate clamping at both ends", and effectively solves the technical problem that the laser head cannot be inserted or the movement is limited due to the narrow inner embedding space.

[0056] The design that the cross beam penetrates the workpiece and the internal fixed turntable is strained enables the workpiece to maintain high stability during rotation, and avoids poor weld forming caused by workpiece vibration or deformation; meanwhile, the driving interfaces are arranged at both ends of the device, and the adjustable characteristics of the supporting mechanism can realize flexible reversing of the tooling, and then the girth welds at both ends of the workpiece which are not coaxial are welded respectively, achieving the effect of "one installation and two weldings", and significantly improving the production efficiency and application flexibility.

[0057] Further, the front flange plate and the rear flange plate are respectively provided with a straining bolt for axially straining the workpiece and a positioning pin for radially limiting:

[0058] In specific implementation, the straining bolt is uniformly distributed along the circumference of the flange plate, penetrates into and abuts against the end surface of the workpiece, and applies uniform axial compression force to the workpiece; at least two positioning pins are arranged on the front flange plate, the cylindrical surface of the positioning pin protrudes radially along the front flange plate, and the cylindrical surface is in clearance fit with the inner wall of the prefabricated positioning hole of the workpiece end frame (the clearance is less than or equal to 0.05 mm), and meanwhile, the end surface of the front flange plate is in abutment with the end surface of the workpiece end frame, and the axial compression force of the straining bolt is combined to realize the circumferential positioning and axial limiting of the workpiece, and prevent the workpiece from slipping when rotating. This design can reliably fix the axial and circumferential positions of the workpiece during high-speed rotary welding, ensure that the laser beam is always accurately aligned with the weld, and guarantee the stability and consistency of the welding quality.

[0059] Further, considering the assembly convenience of the tooling and the adaptability to workpieces of different diameters, the fixed turntable is of a split structure, including an upper half and a lower half, and is fixed as a whole by bolts.

[0060] In assembly, the lower half can be pre-assembled on the beam through the support block, then the workpiece is hoisted into place, and finally the upper half is closed and fastened with bolts. This split design avoids the cumbersome operation of inserting the entire tool from the end of the workpiece, especially suitable for long cylindrical or one-end obstructed workpieces, greatly improving the clamping efficiency. At the same time, by replacing the fixed turntable of different sizes or adjusting the position of the support block on the beam, the device can adapt to workpieces of different diameters and lengths within a certain range, enhancing the versatility of the tool.

[0061] Further, considering the large weight of the fixed turntable itself, in order to facilitate its lifting during assembly, disassembly and maintenance, a third lifting hole is provided on the upper part of each fixed turntable. When installing or disassembling the turntable from the inside of the workpiece, the third lifting hole can be connected with the lifting tool through the crown block (traveling block), realizing safe and labor-saving handling operation.

[0062] Further, in order to improve the overall rigidity and torque transmission capacity of the tool, and avoid relative displacement of the fixed turntable under stress, at least one tensioning pull rod is connected and reinforced between the at least two fixed turntables.

[0063] In implementation, the tensioning pull rod passes through the corresponding connecting hole of each fixed turntable, and the two ends are locked with nuts. This makes the multiple fixed turntables form a whole frame, which collectively resists the torque and radial force generated during welding, further reducing the risk of workpiece vibration and deformation, especially for long thin-walled cylindrical workpieces. This structure can significantly improve the stability of the welding process.

[0064] Further, in order to facilitate the interface matching with different types of positioners, the rotary drive interface can be a hexagonal chuck, a square chuck or a spline chuck, etc.

[0065] Exemplarily, the hexagonal chuck is preferred in this embodiment, as it has the advantages of large torque transmission, convenient docking and no relative sliding. In implementation, the drive shaft of the positioner is inserted into the hexagonal chuck to achieve reliable connection, which is simple to operate and has good connection rigidity.

[0066] Further, in order to facilitate the adjustment of the tool height and make the weld circle center accurately centered with the rotating shaft of the positioner, the support mechanism is a height-adjustable roller bracket. By adjusting the screw rod or pad on the roller bracket, the height of the entire tool and workpiece can be fine-tuned, ensuring that the circle center of the weld on either end of the girth weld can coincide with the rotating axis of the positioner. This is a key step to achieve uniform penetration and attractive appearance of the girth weld.

[0067] Further, in order to increase the modularity and maintenance convenience of the tooling, the support block is detachably connected to the cross beam, for example by bolt connection or keyway fitting. This allows the position of the support block to be flexibly adjusted according to the welds and internal cavity structure on the workpiece, and facilitates replacement of worn parts.

[0068] Further, in view of the safety of hoisting the tooling, a first lifting hole is provided on the device for overall hoisting.

[0069] Preferably, the first lifting hole is provided on the front flange and / or the rear flange. When the assembled workpiece and tooling need to be hoisted as a whole (such as 180° turning), the lifting eye bolts can be connected to these first lifting holes, and the operation can be performed using a crane or hoist, which is safe and stable.

[0070] In addition, a second lifting hole can also be provided separately on the rigid cross beam, mainly for assembly or maintenance hoisting of tooling parts (such as cross beam assemblies).

[0071] It should be noted that the device provided by the embodiments of the present application is particularly suitable for welding two non-coaxial embedded annular welds. The present application takes advantage of the feature that both ends of the tooling can be driven. After welding the weld on one end, the workpiece does not need to be disassembled, and only the tooling needs to be turned over, so that the driving interface on the other end can be connected to the positioner for welding the second weld. This method solves the problem of being unable to complete welding in one clamping due to the non-coaxiality of the two welds.

[0072] On the other hand, one specific embodiment of the present application discloses a laser welding method for welding non-coaxial embedded double-ring welds, comprising the following steps:

[0073] S1. Clamping: fixing a workpiece having two non-coaxial embedded annular welds on a welding tooling, both ends of the tooling being provided with a driving interface capable of being connected to a positioner;

[0074] S2. First weld welding: connecting the first driving interface of the tooling to the positioner, adjusting the position of the positioner so that the center of the first annular weld is coaxial with the rotating shaft of the positioner, starting the positioner and the laser welder, and completing the overall one-time welding of the first annular weld;

[0075] S3. Tooling transformation: disconnecting the first end of the tooling from the positioner, and transforming the position of the tooling as a whole so that the second driving interface of the tooling is connected to the positioner;

[0076] S4. Second weld welding: adjusting the position of the positioner so that the center of the second annular weld is coaxial with the rotating shaft of the positioner, starting the positioner and the laser welder, and completing the overall one-time welding of the second annular weld; the welding parameter range is the same as that of step S2.

[0077] Specifically, in S4, the integral welding refers to, for a complete annular weld, continuously completing the welding without interrupting the laser output and the workpiece rotation, avoiding multiple starting and stopping of the arc, thereby eliminating potential defects at the joint.

[0078] In practice, the method relies on the aforementioned clamping and rotating device. In the clamping step S1, the workpiece is reliably fixed in the tool (the part is pressed tightly by the front flange, the rear flange and the tightening bolts, and is limited by the positioning pins, then the workpiece is locked as a whole by using the fixed turntable and the tensioned pull rod, ensuring no movement during welding). In the welding steps S2 and S4, by precisely adjusting the height of the positioner, the center of the annular weld to be welded is ensured to be coaxial with the rotating shaft of the positioner, at this time the positioner is started to rotate at a constant speed, and the laser welder is started simultaneously, so that the relative static state of the laser beam and the weld position is achieved, and high-quality annular welding is completed. The tool change in S3 is the key, which is usually achieved by lifting and rotating the entire tool and workpiece by 180° to turn around, thereby quickly switching the weld to be welded.

[0079] Compared with the prior art method which needs to be welded in sections or uses complex robot trajectory planning, the method provided by the embodiment greatly simplifies the welding process of the embedded non-coaxial double annular weld by workpiece rotation, laser fixation and combination of reversible special tooling, and guarantees the continuity and consistency of the weld quality.

[0080] The method realizes integral welding of the embedded narrow-space annular weld, fundamentally solves the problems of starting and stopping defects, uneven joint quality and low efficiency caused by sectional welding; by simple tool turning operation, the welding of two different coaxial annular welds can be completed, the process adaptability is good, and the operation is simple.

[0081] Further, in order to guarantee the basic quality of the welded joint and avoid defects such as pores and incomplete fusion caused by surface contaminants, before S1, a part cleaning step is further included: using pickling and / or scraping to remove the oxide film, oil stains and excess materials on the surface of the part to be welded.

[0082] Illustratively, for aluminum alloy materials, pickling is performed first to remove oil stains, and then mechanical scraping is performed to completely remove the dense aluminum oxide film.

[0083] Specifically, the scraping is performed by using a scraper to scrape the front and back surfaces and the butt vertical surface of the position to be welded in the same direction, and the scraping width is 20mm-25mm (for example, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm). Such one-way scraping avoids the re-embedding of the oxide film into the matrix, ensures the exposure of fresh metal luster, provides a clean and active surface for subsequent laser welding, and significantly improves the density and strength of the weld.

[0084] Further, in the S1 clamping, the workpiece with two non-coaxial embedded ring welds is fixed on a welding tool, both ends of the tool are provided with driving interfaces capable of being connected with the positioner. In implementation, the method relies on the aforementioned clamping and rotating device, the workpiece is reliably fixed in the tool, and the specific operation is as follows:

[0085] 1. First, place the crossbeam horizontally, and pre-fix the front flange plate and the rear flange plate to the two ends of the crossbeam through bolts;

[0086] 2. Set the workpiece to be welded outside the crossbeam, so that the front end face of the workpiece is in contact with the inner end face of the front flange plate, and the rear end face is in contact with the inner end face of the rear flange plate;

[0087] 3. Tighten the jacking bolts on the front flange plate and the rear flange plate to apply uniform axial pressing force to the workpiece; insert the positioning pin into the pre-positioning hole of the front flange plate and the workpiece end frame to complete the radial positioning of the workpiece;

[0088] 4. Assemble the fixed turntable: pre-assemble the lower half of the fixed turntable to the crossbeam through the support block, so that the outer end face of the support block is in contact with the inner circumferential wall of the fixed turntable and is fixed by bolts; fold the upper half of the fixed turntable and tighten the bolts, so that the outer circumferential wall of the fixed turntable is tightly pressed against the inner surface of the workpiece barrel wall through interference fit or uniformly distributed jacking screws (the jacking force is controlled at 5-8 N·m), and the contact degree between the fixed turntable and the workpiece barrel wall is ensured to be ≥95%;

[0089] 5. Assemble the tensioning rod: arrange at least one tensioning rod along the axial direction of the crossbeam, and pass the two ends of the rod through the corresponding through holes of the fixed turntable, and tighten the nuts to make the fixed turntable form a rigid whole;

[0090] 6. Assemble the support mechanism: first, pre-assemble the support mechanism with the corresponding first base and second base, and then connect the base with the workbench; adjust the lifting screw at the bottom of the support mechanism to make the top arc-shaped roller group rollingly contact with the outer circumferential wall of the lower half of the fixed turntable, and the support surface is kept horizontal with the axis of the fixed turntable.

[0091] Further, in order to fix the relative position of the parts before formal welding and prevent misplacement during clamping or initial welding, after the S1 step and before the S2 step, a trial assembly and positioning welding step is further included: assemble each part in a sleeved manner to ensure that the gap and step difference are not greater than 0.2 mm; the workpiece is a lock bottom butt joint structure, the welding depth at the circular hole of the end frame is 3-5 mm (for example, 3 mm, 4 mm, 5 mm), and the thickness of the lock bottom is 2-3 mm (for example, 2 mm, 3 mm); then, the assembled parts are fixed by positioning welding using a handheld laser welder.

[0092] It is worth noting that in the positioning welding step, the positioning weld requires penetration on both sides of the base body, and the transition is smooth, and the length of the single positioning weld is 20-30 mm (for example, 20 mm, 22 mm, 25 mm, 28 mm, 30 mm), and the spacing is 100-150 mm (for example, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm); the laser power is 700-900 W (for example, 700 W, 750 W, 800 W, 850 W, 900 W), the laser spot width is 2-4 mm (for example, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm), and the protective gas flow is 8-15 L / min (for example, 8 L / min, 10 L / min, 12 L / min, 15 L / min). The moderate positioning welding parameters can ensure the positioning strength, and the workpiece deformation caused by excessive heat input is avoided, thereby laying a good foundation for subsequent overall welding.

[0093] Further, in order to realize uniform forming of the weld, in the S2 first weld welding and S4 second weld welding steps, the rotating speed of the positioner is consistent with the welding speed of the laser welding. That is, the linear speed of the workpiece rotation is equal to the speed of the laser beam moving along the weld, so that the laser energy can uniformly act on the entire ring seam, thereby obtaining a high-quality weld with consistent width and penetration.

[0094] Further, for the typical aluminum alloy embedded weld structure, in the S2 and S4 steps, for the aluminum alloy weld with a welding depth of 3-5 mm (for example, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm), the laser welding parameters are as follows:

[0095] The laser welding power is 1900-2300 W (for example, 1900 W, 2000 W, 2100 W, 2120 W, 2150 W, 2200 W, 2300 W); the laser beam deflection is 0.5-0.8 (for example, 0.5, 0.6, 0.7, 0.8); the welding speed is 0.007-0.011 m / s (for example, 0.007 m / s, 0.008 m / s, 0.009 m / s, 0.010 m / s, 0.011 m / s); the laser frequency is 180-220 Hz (for example, 180 Hz, 190 Hz, 200 Hz, 210 Hz, 220 Hz); and the protective gas is argon with a flow rate of 8-15 L / min (for example, 8 L / min, 9 L / min, 10 L / min, 11 L / min, 12 L / min, 13 L / min, 14 L / min, 15 L / min).

[0096] This series of optimized parameter combination can effectively control heat input under the premise of ensuring penetration, avoid burning through, collapse or produce too many pores, and obtain the weld with beautiful appearance and excellent internal quality.

[0097] Specifically, in the S2 and S4 steps, the whole one-time welding refers to continuously completing welding for one complete ring-shaped weld without interrupting laser output and workpiece rotation, avoiding multiple starting and stopping of arc, and eliminating potential defects at the joint.

[0098] Further, the tool change of S3 is one of the keys, which is usually achieved by lifting and rotating the entire tool and workpiece by 180° to quickly switch the weld to be welded, and is specifically performed as follows:

[0099] (1) As shown in Figure 1 , a first base is arranged on the outside of the front flange plate, and a second base is arranged on the outside of the rear flange plate, and the bases and the support mechanism form a complete support system; during tool change, first, the positioner connected with the drive interface (such as the first drive interface) at the end of the welded weld is removed, and then the connecting fastener between the first base and the workbench is removed to separate the first base from the front flange plate, at this time, the tool state can be referred to Figure 4 (i.e. Figure 3 the structure after the base is removed), so that the second weld area to be welded is completely exposed;

[0100] (2) The lifting device is connected through the first lifting hole of the front flange plate and the second lifting hole of the rear flange plate, and the tool and the workpiece are lifted to a suspended state, and the crossbeam is kept horizontal and rotated by 180° around the axis;

[0101] (3) Adjust the position of the tool to align the second drive interface with the connecting end of the positioner, and fix the second base to the workbench to restore the assembly of the support mechanism and the second base to the complete support state shown in Figure 3 ;

[0102] (4) Connect and fix the second drive interface with the positioner to complete the tool change.

[0103] This method is simple and efficient, and fully utilizes the characteristics of the symmetrical design of the two ends of the tool to achieve rapid welding change.

[0104] Further, in the S4 second weld welding, the welding parameter range is the same as that of the S2 first weld welding. The protective gas needs to continuously cover the weld area to avoid air intrusion and oxidation.

[0105] To finally verify the weld quality, after the S4 step, a detection step is further included: radiographic detection (to ensure that there is no excessive defect inside the weld) and / or fluorescent detection (to check surface cracks, pinholes and other defects of the weld), and the tensile strength of the weld is not less than 91% of the base material strength. These ensure that the welded joint meets the high-standard quality requirements, such as the commonly used Class I joint standard in the aerospace field.

[0106] Compared with the method in the prior art which needs to be welded in sections or uses complex robot trajectory planning, the method provided by the embodiment greatly simplifies the welding process of the embedded non-coaxial double-ring weld through workpiece rotation, laser fixation and in combination with reversible special tooling, and guarantees the continuity and consistency of the weld quality.

[0107] The method realizes overall one-time welding of the embedded narrow-space ring weld, and fundamentally solves the problems of arc extinguishing defects, uneven joint quality and low efficiency caused by sectional welding; through simple tooling turning operation, welding of two different axial ring welds can be completed, and the process adaptability is good and the operation is simple.

[0108] The application will be described in more detail below through specific embodiments. The embodiments are only a description of the best mode of the application and do not have any limitation on the scope of the application.

[0109] Embodiment 1

[0110] A certain type of aluminum alloy aircraft cabin section having two non-coaxial embedded ring welds is welded using the clamping and rotating device of the application and the welding method of the application.

[0111] The clamping and rotating device is as shown in Figure 1 and Figure 2 . It includes: a rigid crossbeam which axially passes through the inside of the cylindrical workpiece to be welded; a front flange plate and a rear flange plate which are respectively fixed to the two ends of the crossbeam and are used to axially clamp and radially position the workpiece from both ends; at least two fixed rotating discs which are fixed to the crossbeam through support blocks and are located inside the workpiece, and are used to internally support the workpiece to enhance its rigidity and transmit torque; two rotating drive interfaces which are respectively arranged on the outer sides of the front flange plate and the rear flange plate, and are used to be selectively connected with the external positioner; and a support mechanism which is correspondingly arranged below the fixed rotating discs, and is used to support the fixed rotating discs and support the entire device on the workbench.

[0112] The front flange plate and the rear flange plate are provided with a jacking bolt for axially jacking the workpiece and a positioning pin for radially limiting. The fixed rotary disc is a split structure, comprising an upper half and a lower half, and is fixed as a whole through bolt connection. The two fixed rotary discs are connected and reinforced through a circumferentially distributed tensioning pull rod. The rotary drive interface is a hexagonal chuck. The support mechanism is a height-adjustable roller bracket. The support block and the cross beam are detachably connected. A first lifting hole is formed on the device for overall hoisting. The first lifting hole is formed on the front flange plate and / or the rear flange plate.

[0113] The welding method using the above-mentioned clamping rotary device comprises the following steps:

[0114] S1. Clamping: fixing the cleaned and positioned workpiece after welding on the tooling.

[0115] S2. First weld seam welding: connecting the hexagonal chuck at one end of the tooling with the positioner, adjusting the height of the positioner to make the center of the first girth weld (welding depth 4.0 mm) coaxial with the rotating shaft of the positioner. Set the laser welding power to 2120W, the deflection to 0.6, the welding speed to 0.009m / s, the frequency to 200Hz, and the argon flow rate to 10L / min. Start the positioner and the laser welder to complete the overall one-time welding of the first girth weld.

[0116] S3. Tooling change: disconnect the tooling from the positioner, and turn the tooling over by 180°.

[0117] S4. Second weld seam welding: connecting the hexagonal chuck at the other end of the tooling with the positioner, and adjusting the centering. The same welding parameters as in S2 are used to complete the overall one-time welding of the second girth weld.

[0118] Example 2

[0119] This example is based on the device described in Example 1, and the steps are the same as in Example 1, but for slightly thinner welds (welding depth 3.5 mm), the welding parameters are adjusted as follows: laser power 1950W, deflection 0.6, welding speed 0.010m / s, frequency 200Hz, argon flow rate 10L / min.

[0120] Example 3

[0121] This example combines the device of Example 1. Before S1 clamping, the welding area is cleaned by strictly using pickling followed by mechanical scraping, with a scraping width of 22mm. During the positioning welding, a laser power of 850W, a spot width of 3.5mm, and an argon flow rate of 9L / min are used to perform positioning welding with a length of 25mm and a spacing of 120mm. The formal welding parameters are the same as in Example 1.

[0122] Comparative Example 1

[0123] The comparative example uses a traditional three-jaw chuck to clamp one end of the workpiece, and the other end is in a free state for laser welding. The welding method and parameters are the same as in Example 1.

[0124] Comparative Example 2

[0125] This comparative example uses the device of Example 1, and when welding the second weld (S4 step), the position of the positioner is not adjusted so that the center of the second girth weld is coaxial with the rotating shaft of the positioner. The welding parameters are the same as in Example 1.

[0126] Comparative Example 3

[0127] This comparative example uses the device of Example 1, and when welding each girth weld, it uses segmented welding (pauses once every 1 / 3 turn), which disrupts the continuity of the welding process. The welding parameters are the same as in Example 1.

[0128] Comparative Example 4

[0129] This comparative example uses the device of Example 1, and the welding parameters are: laser power 2500W, welding speed 0.015m / s, and other parameters are the same as in Example 1.

[0130] Characterization results and analysis

[0131] The characterization results of the above-described examples and comparative examples are shown in the following table.

[0132] Table 1. Comparison of weld quality and mechanical properties

[0133]

[0134] As can be seen from the table, using the device and method provided by the present application (Examples 1-3), the obtained welds have good to excellent appearance, the results of radiographic testing are all grade I, no defects, and the tensile strength reaches more than 91% of the strength of the base material, showing stable high-quality welding performance.

[0135] In contrast, all the comparative examples have poor weld surface quality, internal defects such as incomplete fusion, porosity or incomplete penetration, and the results of radiographic testing are grade II or unqualified, and the tensile strength is only 72.3%-87.2% of the strength of the base material, with a significant decrease in mechanical properties, due to unstable tooling, inaccurate centering, segmented welding or incorrect parameters.

[0136] In summary, through the innovative design of the clamping rotary device and the matching welding method, the present application successfully solves the technical bottleneck of non-coaxial embedded girth weld laser welding, realizes overall one-time welding with high quality and high efficiency, and has broad application prospects in high-end manufacturing fields such as aerospace.

[0137] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A clamping and rotating device for laser welding of embedded circumferential welds, characterized in that, include: A rigid crossbeam (8) passes through the interior of the cylindrical workpiece to be welded in sequence along its axial direction; The front flange (1) and the rear flange (2) are fixed to the two ends of the crossbeam (8) respectively, for axial clamping and radial positioning of the workpiece from both ends; At least two fixed turntables, which are fixed to the crossbeam (8) by support blocks (6) and located inside the workpiece, are used to tighten the workpiece from the inside to enhance its rigidity and transmit torque; Two rotary drive interfaces are respectively located on the outside of the front flange (1) and the rear flange (2) for selectively connecting to an external positioner drive. In addition, a support mechanism is provided below the fixed turntable to support the fixed turntable and support the entire device on the working platform.

2. The apparatus according to claim 1, characterized in that, The front flange (1) and the rear flange (2) are provided with clamping bolts for axially clamping the workpiece and locating pins (3) for radial limiting.

3. The apparatus according to claim 1, characterized in that, The fixed turntable has a split structure, consisting of an upper part and a lower part, which are fixed together as one unit by bolts.

4. The apparatus according to claim 1, characterized in that, The at least two fixed turntables are connected and reinforced by at least one tensioning rod (7) distributed circumferentially.

5. The apparatus according to claim 1, characterized in that, The rotary drive interface is a hexagonal chuck, a square chuck, or a spline chuck.

6. The apparatus according to claim 1, characterized in that, The support mechanism is a height-adjustable roller bracket.

7. The apparatus according to claim 1, characterized in that, The support block (6) and the crossbeam (8) are detachably connected.

8. The apparatus according to claim 1, characterized in that, The device is provided with a first lifting hole (15) for overall hoisting.

9. The apparatus according to claim 8, characterized in that, The first lifting hole (15) is provided on the front flange (1) and / or the rear flange (2).

10. A welding method, characterized in that, Using the clamping and rotating device according to any one of claims 1 to 9, and comprising the following steps: S1. Clamping: Fix the workpiece with two non-coaxial embedded circumferential welds onto a welding fixture, both ends of which are provided with drive interfaces that can be connected to a positioner. S2. First weld: Connect the first drive interface of the tooling to the positioner, adjust the positioner so that the center of the first circumferential weld is coaxial with the rotation axis of the positioner, start the positioner and the laser welding machine, and complete the overall one-time welding of the first circumferential weld; S3. Tooling Change: Disconnect the first end of the tooling from the positioner, change the position of the entire tooling, and connect the second drive interface of the tooling to the positioner; S4. Second weld: Adjust the positioner so that the center of the second circumferential weld is coaxial with the rotation axis of the positioner. Start the positioner and laser welding machine to complete the overall one-time welding of the second circumferential weld.

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