Aluminum alloy thin-walled cabin body friction stir spot welding device and method

Abstract

The application discloses an aluminum alloy thin-wall cabin friction stir spot welding device and method, and relates to the technical field of welding. The device comprises a bearing support, a roller assembly, a speed reduction drive mechanism, a wedge self-locking clamping mechanism and a spot welding tool. The roller assembly is used to fix and adjust the angle and position of the welding workpiece. The speed reduction drive mechanism realizes high-precision positioning through a worm gear reducer. The clamping mechanism ensures the stability of the workpiece. The wedge self-locking clamping mechanism comprises a flange plate and a bracing plate, and is used to clamp the welding workpiece. The spot welding tool is used to perform the friction stir spot welding operation. The welding method comprises the steps of surface cleaning, clamping the workpiece, accurately positioning the welding spot, performing the friction stir spot welding, post-welding cooling and quality detection. The welding method is suitable for 2219-T851 aluminum alloy and 2195-T84 aluminum-lithium alloy, and optimizes the welding parameters, improves the welding quality and efficiency. The application has the advantages of high welding quality, efficiency improvement, energy consumption reduction, waste reduction and the like, and is suitable for high-end equipment manufacturing fields such as aerospace and aviation.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, specifically relating to a friction stir spot welding device for thin-walled aluminum alloy cabins. Background Technology

[0002] Aluminum alloys, due to their low density, high specific strength, excellent corrosion resistance, and good machinability, have become a core structural material in the aerospace field. With the development of advanced aerospace equipment such as reusable launch vehicles, large aluminum alloy thin-walled cabin structures are widely used due to their lightweight and high-strength requirements. These cabins typically employ a structural design combining thin-walled skin and a frame, with skin thicknesses of only 1-2 mm and overall diameters and heights reaching several meters, requiring numerous high-precision spot welds. Due to the high thermal conductivity and surface oxide film stability of aluminum alloys, the application of traditional welding methods in thin-walled cabin welding is significantly limited, making it difficult to meet the demands of high efficiency, high reliability, and lightweight aerospace manufacturing.

[0003] Currently, common connection methods for thin-walled aluminum alloy cabins mainly include riveting, resistance spot welding, and friction stir welding. However, the first two have significant limitations. Riveting requires drilling holes in the workpiece and using rivets, which not only increases the structural weight but also weakens the material integrity, easily leading to stress concentration and reducing the fatigue life of the cabin. Furthermore, riveting is a complex process with low welding efficiency, making it difficult to meet the high-efficiency connection requirements of large-size, complex structures. While resistance spot welding is a mature technology, the high thermal conductivity of aluminum alloys allows for easy heat dissipation, resulting in insufficient local heating and difficulty in guaranteeing weld strength. Simultaneously, the high melting point and strong stability of the oxide film on the aluminum alloy surface make it difficult for resistance spot welding to effectively remove the oxide film, easily leading to weld inclusions or cracks, affecting weld quality. In addition, the adhesion between the electrode and the workpiece increases maintenance costs. Therefore, these traditional methods suffer from increased weight, unstable weld quality, and low efficiency in welding large-size thin-walled aluminum alloy cabins, making it difficult to meet the high reliability requirements of aerospace manufacturing.

[0004] Friction stir spot welding (FSSW) is an advanced solid-state welding technology. Its principle involves using frictional heat generated by a rotating stirring pin to bring the material in the welding area to a plastic state, thus forming a high-strength connection. Compared to traditional riveting and resistance spot welding, this technology eliminates the need for filler material or drilling, avoiding material damage and enabling lightweight design. Furthermore, this technology does not melt the base material during welding, resulting in a crack-free and porosity-free weld joint, with weld strength reaching over 90% of the base material's strength. In addition, FSSW has lower energy consumption and avoids the high-temperature oxidation and pollutant emissions associated with resistance spot welding, meeting green manufacturing requirements. However, existing FSSW equipment still suffers from limitations in welding large-size aluminum alloy thin-walled cabins, including weak weld quality monitoring capabilities, low multi-point welding efficiency, and limited precision in welding parameter control. These limitations hinder its application in high-performance aerospace manufacturing.

[0005] Therefore, there is an urgent need to develop a friction stir spot welding device and method suitable for aluminum alloy thin-walled cabin structures to solve the technical problems of poor welding quality consistency, low process efficiency and insufficient equipment adaptability in the manufacturing of aerospace thin-walled components. Summary of the Invention

[0006] The purpose of this invention is to provide a friction stir spot welding device for thin-walled aluminum alloy cabins to solve the above-mentioned technical problems existing in the prior art.

[0007] To achieve the above objectives, in one aspect, the present invention provides an aluminum alloy thin-walled chamber friction stir spot welding apparatus, comprising:

[0008] Two spaced-apart bearing supports are used to support the main body of the device;

[0009] A roller assembly is rotatably connected between two bearing supports. The roller assembly includes a reducer mounting shaft, a shaft, a small flange, a positioning plate, a cone, and a large flange. The small end of the cone is fixed by the small flange, and the large end is fixed by the large flange.

[0010] The speed reduction drive mechanism includes a worm gear reducer, which is fixed to a bearing support on one side by a reducer bracket and is connected to the roller assembly for controlling the welding path.

[0011] A wedge-shaped self-locking clamping mechanism includes a flange and a support plate, wherein the flange is bolted to the support plate and is used to clamp the welded workpiece;

[0012] Spot welding tools are used to perform friction stir spot welding operations.

[0013] Optionally, the roller assembly and the tensioning plate are wedge-shaped.

[0014] Optionally, the cone angle of the wedge fit is 6°.

[0015] Optionally, it also includes a vision inspection system for acquiring solder joint images and performing quality analysis via computer; the vision inspection system acquires solder joint images using a high-resolution industrial camera and automatically judges the surface quality of the solder joints using computer image processing algorithms.

[0016] Optionally, the reduction drive mechanism further includes a handwheel connected to the input end of the worm gear reducer for manual drive adjustment.

[0017] Optionally, the flange includes a top plate, reinforcing ribs, and a ring. The flange is connected to the support plate by a round nut and two bolts. The axial position of the flange can be adjusted by adjusting the position of the round nut on the shaft.

[0018] In another aspect, the present invention also provides a friction stir spot welding method, according to the aluminum alloy thin-walled chamber friction stir spot welding apparatus according to any one of the above claims, the method comprising the following steps:

[0019] Step S1: Clean the surface of the welding area of ​​the aluminum alloy thin-walled chamber to remove oxide film and impurities;

[0020] Step S2: Clamp the hull skin and hull frame using a wedge-shaped self-locking clamping mechanism;

[0021] Step S3: Adjust the position of the roller assembly using the worm gear reducer to precisely locate the welding points;

[0022] Step S4: Start the spot welding tool, set the rotation speed to 2000-3500 rpm, the indentation to 1.2-2.2 mm, and the welding time to 3.0-5.0 seconds / point, and perform friction stir spot welding;

[0023] Step S5: Allow the material to cool naturally after welding, and keep it clamped to prevent deformation;

[0024] Step S6: Perform quality analysis on the solder joints. If the quality is qualified, proceed to the next solder joint.

[0025] In some alternative methods of the present invention, in step S6, a visual inspection system is used to perform quality analysis on the solder joints.

[0026] In some optional methods of the present invention, in step S4, when the welding material is 2219-T851 aluminum alloy, the rotation speed is set to 2800-2900 rpm, the indentation is 1.8-2.0 mm, and the welding time is 4.0-4.2 seconds / point.

[0027] In some optional methods of the present invention, in step S4, when the welding material is 2195-T84 aluminum-lithium alloy, the rotation speed is set to 2950-3050 rpm, the indentation amount is 1.2-1.5 mm, and the welding time is 3.5-3.8 seconds / point.

[0028] The present invention discloses the following technical effects:

[0029] This invention significantly improves welding quality, production efficiency, and stability by optimizing the welding device structure, implementing precise positioning control, and employing intelligent quality inspection, offering the following advantages:

[0030] 1. Welding quality has been significantly improved.

[0031] This invention uses a visual inspection system to automatically identify the quality of weld points, reduce human error, ensure welding consistency, and achieve weld point strength of over 90% of the base material. The tensile strength and mechanical properties of the welded joint are stable, and the weld structure is uniform and defect-free.

[0032] 2. Welding efficiency is greatly improved

[0033] High-precision worm gear reducers and automatic positioning systems can reduce welding path adjustment time, improve the overall efficiency of multi-point welding, increase welding speed by more than 30%, and significantly improve overall welding efficiency.

[0034] 3. Lower energy consumption

[0035] This invention optimizes energy transmission and welding processes, reducing overall energy consumption by more than 20%, while avoiding oxidation and fume emissions caused by high-temperature welding, which aligns with the concept of green manufacturing and is more environmentally friendly.

[0036] 4. The scrap rate has been significantly reduced.

[0037] The intelligent inspection system can monitor the quality of weld points in real time, reducing the defect rate by more than 40%, reducing material waste, and improving production efficiency.

[0038] 5. The welding process is more stable.

[0039] The wedge-shaped self-locking clamping mechanism improves welding accuracy, avoids quality problems caused by workpiece slippage during welding, ensures stable weld point position, and improves the reliability and service life of weld structure.

[0040] This invention is applicable to high-end equipment manufacturing fields such as aerospace, aviation, and automobile manufacturing, and is particularly suitable for welding reusable rocket propellant tanks. It can effectively improve structural strength, reduce weight, and extend service life, providing an efficient, energy-saving, and reliable welding solution for aerospace manufacturing. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the aluminum alloy thin-walled chamber friction stir spot welding device of the present invention;

[0043] Figure 2 This is a front view of the bearing support in the device of the present invention;

[0044] Figure 3 This is a side view of the bearing support in the device of the present invention;

[0045] Figure 4 This is a front view of the reducer bracket in the device of the present invention;

[0046] Figure 5 This is a side view of the reducer bracket in the device of the present invention;

[0047] Figure 6 This is a front view of the flange in the device of the present invention;

[0048] Figure 7 This is a side view of the flange in the device of the present invention;

[0049] Figure 8 This is a front view of the roller assembly in the device of the present invention;

[0050] Figure 9 This is a side view of the roller assembly in the device of the present invention.

[0051] The components are as follows: 1. Bearing support; 2. Bolt 1; 5. Reducer bracket; 6. Worm gear reducer; 8. Handwheel; 9. Bearing with seat; 10. Round nut; 11. Flange; 12. Bolt 2; 13. Stiffening plate; 14. Roller assembly; 15. Hull skin; 16. Hull frame; 17. Spot welding tool; 18. Vision inspection system; 19. Computer; 20. Bracket mounting plate; 21. Bearing mounting plate; 22. Horizontal brace; 23. Vertical brace; 24. Base plate; 25. Reducer mounting plate; 26. Reinforcing plate; 27. Side plate; 28. Top plate; 29. ​​Reinforcing rib; 30. Ring; 31. Reducer mounting shaft; 32. Shaft; 33. Small flange; 34. Positioning plate; 35. Tapered cylinder; 36. Large flange. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] This invention discloses a friction stir spot welding device and method for aluminum alloy thin-walled cabins, aiming to solve the problems of unstable welding quality, low efficiency, and insufficient equipment adaptability in the manufacturing of aerospace thin-walled components using existing welding technologies. To make the above-mentioned objectives, features, and advantages of this invention more apparent and understandable, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] Example 1

[0055] Reference Figures 1 to 9 As shown, Embodiment 1 of the present invention provides a friction stir spot welding device for aluminum alloy thin-walled chambers, including a spot welding tool 17, a vision inspection system 18, a roller assembly 14, a wedge-shaped self-locking clamping mechanism, a reduction drive mechanism, and a bearing support 1. Wherein, as... Figure 1 As shown, two bearing supports 1 are spaced apart to support the entire spot welding device; the roller assembly 14 is rotatably connected to the two bearing supports 1, and one end of it is connected to the reduction drive mechanism to support and fix the welding workpiece (aluminum alloy thin-walled cabin) and to adjust the angle and position of the welding point; the reduction drive mechanism is fixed to one side of the bearing support 1 through the reducer bracket 5 to precisely adjust the welding path and ensure high-precision positioning of the welding point; the wedge-shaped self-locking clamping mechanism includes a flange 11 and a support plate 13 to firmly clamp the aluminum alloy thin-walled cabin and prevent displacement or deformation during welding; the spot welding tool 17 is used to perform friction stir spot welding to form a high-strength connection between the aluminum alloy skin and the skeleton; the vision inspection system 18 is used to collect the appearance image of the weld point after welding and transmit the data to the computer 19 for quality analysis; the vision inspection system 18 is connected to the computer 19, which receives and processes the weld point image acquired by the vision inspection system 18 and uses image analysis algorithms to determine whether the weld point quality is qualified.

[0056] Specifically, such as Figure 2 and Figure 3 As shown, the bearing support 1 includes a bracket mounting plate 20, a bearing mounting plate 21, a cross brace 22, a vertical brace 23, and a base plate 24, all made of Q235 steel. The bearing support 1 is used for fixed connection between the device and the friction stir spot welding equipment, and also for connection with the reducer bracket 5 and the seated bearing 9.

[0057] like Figure 4 and Figure 5As shown, the reducer bracket 5 includes a reducer mounting plate 25, a reinforcing plate 26, and a side plate 27, all made of Q235 steel. The reducer bracket 5 is connected to the bearing support 1 and is used to fix the worm gear reducer 6. Specifically, the reducer bracket 5 is fixedly installed on one side of the bearing support 1 by bolt 2, and a spring washer and a flat washer are provided at the installation position.

[0058] like Figure 1 As shown, the speed reduction drive mechanism includes a worm gear reducer 6, which is fixed on the reducer bracket 5. Its input end is connected to a handwheel 8. By manually rotating the handwheel 8, the worm is driven to rotate, which in turn drives the worm gear to rotate, thereby realizing the local movement or position adjustment of the equipment.

[0059] like Figure 6 and Figure 7 As shown, the flange 11 is mainly composed of a top plate 28, a reinforcing rib 29, and a ring 30. The top plate 28, the reinforcing rib 29, and the ring 30 are all made of Q235 steel. The flange 11 is connected to a round nut 10 and a tensioning plate 13. By adjusting the position of the round nut 10 on the shaft 32, the axial position of the flange 11 can be adjusted. The tensioning plate 13 is moved axially in the direction of the shaft 32 by bolt 2 12, so that the tensioning plate 13 clamps the hull skin 15 and the hull frame 16.

[0060] like Figure 8 and Figure 9 As shown, the roller assembly 14 is welded together from a reducer mounting shaft 31, a shaft 32, a small flange 33, a positioning plate 34, a cone cylinder 35, and a large flange 36. The reducer mounting shaft 31 is used for transmission connection with the worm gear reducer 6. The shaft 32 is coaxially connected to the reducer mounting shaft 31. The cone cylinder 35 is fixed to the outer periphery of the shaft 32. The end of the cone cylinder 35 closest to the worm gear reducer 6 is the small end, fixed by the small flange 33. The end of the cone cylinder 35 furthest from the worm gear reducer 6 is the large end, fixed by the large flange 36. Considering both the economy and reliability of the structure, the positioning plate 34, small flange 33, and large flange 36 are made of Q235 steel, while the reducer mounting shaft 31, shaft 32, and cone cylinder 35 are made of 20# steel.

[0061] The roller assembly 14 and the support plate 13 adopt a wedge fit. Considering the operability of the relative movement between the two and the self-locking reliability of the working process, a 6° conical surface fit is adopted here. Since the two mounted bearings 9 and the worm gear reducer 6 are connected in series on the same shaft 32, in order to reduce the additional resistance torque in the transmission process, the shoulder part of the shaft 32 that mates with the mounted bearings 9 adopts a hole-basis system, with a diameter of 100mm. Using these two shaft 32 shoulders as a reference, the shaft 32 shoulder that mates with the worm gear reducer 6 is then machined, also using a hole-basis system, with a machining dimension of 35mm in diameter and a circular runout of 0.05mm.

[0062] In the above embodiments, the deceleration drive mechanism works in conjunction with the spot welding tool 17 to precisely adjust the angle and position of the welding head under different welding paths, so as to adapt to the multi-point welding requirements of complex structures.

[0063] In the above embodiments, the clamping force of the wedge-shaped self-locking clamping mechanism can be adjusted according to the thickness of the welding material and process requirements to ensure a tight fit between the aluminum alloy skin and the frame and improve the consistency of the weld points.

[0064] In the above embodiments, the visual inspection system 18 acquires solder joint images using a high-resolution industrial camera and automatically judges the surface quality of the solder joints using computer image processing algorithms to ensure that the solder joints meet preset standards.

[0065] In one specific embodiment, the outer envelope dimensions of the aluminum alloy thin-walled chamber friction stir spot welding device are: length × width × height = 1820mm × 420mm × 730mm.

[0066] The working principle of the spot welding device in this embodiment:

[0067] 1. Axial Friction Stir Spot Welding in the 32-Direction: The hull skin 15 is fitted onto the support plate 13, with its end face fitting against the end face of the roller assembly 14. The hull frame 16 inside the hull skin 15 is placed in the slot of the support plate 13. The support plate 13 and the roller assembly 14 are engaged with a wedge-shaped surface. During operation, the screws on the flange 11 cause the support plate 13 to move axially in the 32-direction relative to the roller assembly 14, thereby clamping the support plate 13 onto the hull skin 15. In this way, axial friction stir spot welding can be achieved between the hull skin 15 and the hull frame 16.

[0068] 2. Radial friction stir spot welding: The worm gear reducer 6 is operated by the handwheel 8. The worm gear reducer 6 drives the cabin skin 15, the tensioning plate 13 and the roller assembly 14 to rotate, so as to realize the radial friction stir spot welding of the cabin skin 15 and the cabin frame 16 at different points.

[0069] It should be understood that, in practical applications, the speed reduction drive mechanism can also be other speed reduction drive structures or mechanical devices that can convert the high-speed rotational motion of the input shaft 32 into the low-speed, high-torque rotational motion of the output shaft 32. For example, it can be a gear reducer, a planetary gear reducer, etc.

[0070] Example 2

[0071] Embodiment 2 of the present invention provides a friction stir spot welding method for 2219-T851 aluminum alloy thin-walled chambers, which is based on the friction stir spot welding device for aluminum alloy thin-walled chambers described in Embodiment 1. This welding method is suitable for 2219-T851 aluminum alloy thin-walled chambers with a diameter of 3.5m and a height of 2.8m, a skin thickness of 1.8mm, and a frame made of 2219 aluminum alloy profiles. All weld joints are friction stir spot welded joints. The spot welding method includes the following steps:

[0072] Step S1: Cleaning before welding

[0073] Before welding, the welding areas of the aluminum alloy cabin skin 15 and cabin frame 16 are mechanically ground with 400# sandpaper to remove surface oxide film and dirt. Then, the welding parts are wiped with industrial ethanol to ensure that their surfaces are free of oil, impurities and dust, thereby avoiding defects such as porosity, inclusions or cracks during the welding process.

[0074] Step S2: Clamping the workpiece

[0075] The cabin components (cabin skin 15 and cabin frame 16) are secured in the friction stir spot welding apparatus, and the workpiece is clamped using flange 11 and support plate 13. By adjusting the clamping force, it is ensured that the workpiece does not deform or shift during the welding process. The wedge-shaped self-locking clamping mechanism provides a stable clamping force and can be appropriately adjusted according to the workpiece size and welding process requirements.

[0076] Step S3, Welding Path Positioning

[0077] The position of the roller assembly 14 is adjusted by the worm gear reducer 6 to precisely align with the welding point area. The high-precision transmission system ensures that the welding path meets the preset requirements, guaranteeing the uniformity and consistency of the weld points.

[0078] Step S4: Perform welding

[0079] During the welding process, welding parameters can be set within the following range:

[0080] Spot welding tool 17: Rotation speed: 2000-3500 revolutions per minute (rpm);

[0081] Stirring needle insertion depth: 1.2-2.2 mm;

[0082] Welding time: 3.0-5.0 seconds / point.

[0083] In this embodiment, based on the material properties of the 2219-T851 aluminum alloy thin-walled cabin, welding parameters are optimized to obtain the best welding quality. The specific parameter settings are as follows:

[0084] Spot welding tool 17: Rotation speed: 2800-2900 revolutions per minute (rpm);

[0085] Indentation depth: 1.8-2.0 mm;

[0086] Welding time: 4.0-4.2 seconds / point;

[0087] After the welding machine is started, the spot welding tool 17 rotates at high speed and is slowly inserted into the welding part. The base material is brought to a plastic state through frictional heat generation, and a high-strength connection is formed during the stirring process.

[0088] Step S5, Post-weld cooling

[0089] After welding, the weld joint is allowed to cool naturally at room temperature to avoid residual stress or microcracks in the welded area due to rapid cooling; the workpiece is kept clamped during the cooling process to prevent the welded joint from deforming due to thermal shrinkage.

[0090] Step S6: Post-weld quality inspection

[0091] After the welding has cooled, the visual inspection system 18 collects the appearance image of the weld point and transmits the data to the computer 19. The computer 19 automatically analyzes the weld point morphology and determines whether the weld point meets the welding quality requirements. If the inspection result is qualified, the welding device is adjusted, moved to the next weld point, and the welding process is repeated. If the inspection result is unqualified, the system automatically prompts for re-welding or repair to ensure that all weld points meet the design standards. By inspecting each point, welding defects can be effectively reduced, welding quality consistency can be improved, scrap rate can be reduced, and weld points can be ensured to meet aerospace-grade quality requirements.

[0092] Compared with existing technologies, this embodiment discloses at least the following beneficial effects: This embodiment optimizes the welding device structure and welding process for the welding requirements of 2219-T851 aluminum alloy thin-walled cabins, significantly improving welding quality and efficiency. Compared with traditional welding methods, the tensile strength of the weld joint is increased to 92% of the base material strength, the weld microstructure is uniform, there are no keyhole defects, and the mechanical properties after welding are stable. By adopting a point-by-point welding + real-time detection mode, the consistency of weld quality is improved by 35%, and the welding qualification rate reaches over 98%, significantly reducing the rework rate caused by welding defects. Simultaneously, the optimized worm gear reduction mechanism improves welding positioning accuracy, reduces welding path adjustment time by 30%, and increases overall welding efficiency by 40%. Furthermore, this invention uses friction stir welding, avoiding the high-temperature oxidation and welding spatter problems of traditional fusion welding, making the welding process more environmentally friendly, reducing welding energy consumption by 18%, and meeting green manufacturing requirements.

[0093] Example 3

[0094] Embodiment 3 of the present invention provides a friction stir spot welding method for a 2195-T84 aluminum-lithium alloy thin-walled cabin body. This method uses the friction stir spot welding device for aluminum alloy thin-walled cabin bodies described in Embodiment 1. This spot welding method is suitable for 2195-T84 aluminum-lithium alloy thin-walled cabin bodies with a skin thickness of 1.2 mm and a frame made of 2195 aluminum-lithium alloy profiles. The scaled-down model of the welded aerospace cabin body has a diameter of 1.6 m and a height of 1.2 m. All weld joints are friction stir spot welds. The spot welding method includes the following steps:

[0095] Step 1: Cleaning before welding

[0096] Use 600# fine sandpaper to lightly polish the contact surfaces of the aluminum-lithium alloy cabin skin 15 and cabin frame 16 to remove the surface oxide film and avoid affecting the welding quality; then use a lint-free gauze soaked in industrial ethanol to thoroughly wipe the welding area to ensure that there is no oil, dust or other impurities, so as to prevent the formation of pores or inclusions during the welding process.

[0097] Step S2: Clamping the workpiece

[0098] The scaled-down model of the aerospace cabin is fixed in the aluminum alloy thin-walled cabin friction stir spot welding device of the present invention. The positions of the flange 11 and the support plate 13 are adjusted so that the cabin skin 15 and the cabin frame 16 can fit together stably and ensure that the workpiece will not be displaced or deformed during the welding process.

[0099] Step S3, Welding Path Positioning

[0100] The position of the roller assembly 14 is adjusted by the worm gear reducer 6 to precisely align with the welding point area. The high-precision transmission system ensures that the welding path meets the preset requirements, guaranteeing the uniformity and consistency of the welding points.

[0101] Step S4: Perform welding

[0102] Based on the material properties of the 2195-T84 aluminum-lithium alloy thin-walled chamber, welding parameters were optimized to obtain the best welding quality. The specific parameter settings are as follows:

[0103] The spot welding tool 17 has a rotation speed of 2950-3050 revolutions per minute (rpm).

[0104] The indentation depth is set to 1.2-1.5 mm.

[0105] The welding time is set to 3.5-3.8 seconds per point;

[0106] Start the welding machine, and after the spot welding tool 17 rotates at high speed, it is slowly inserted into the welding part. The base material is brought to a plastic state by frictional heat generation, and a high-strength connection is formed during the stirring process.

[0107] Step S5, Post-weld cooling

[0108] After welding, the weld joint is allowed to cool naturally at room temperature to avoid residual stress or microcracks in the welded area due to rapid cooling. During the cooling process, the workpiece is kept clamped to prevent deformation of the welded joint due to thermal shrinkage.

[0109] Step S6: Post-weld quality inspection

[0110] After the welding has cooled, the visual inspection system 18 collects the appearance image of the weld point and transmits the data to the computer 19. The computer 19 automatically analyzes the weld point morphology and determines whether the weld point meets the welding quality requirements. If the inspection result is qualified, the welding device is adjusted, moved to the next weld point, and the welding process is repeated. If the inspection result is unqualified, the system automatically prompts for re-welding or repair to ensure that all weld points meet the design standards. By inspecting each point, welding defects can be effectively reduced, welding quality consistency can be improved, scrap rate can be reduced, and weld points can be ensured to meet aerospace-grade quality requirements.

[0111] Compared with existing technologies, this embodiment discloses at least the following beneficial effects: This embodiment optimizes welding process parameters to meet the welding requirements of 2195-T84 aluminum-lithium alloy thin-walled cabins, improving welding stability and joint mechanical properties. The tensile strength of the welded joint reaches 90% of the base material strength, the weld surface is smooth, the weld seam is dense, and there are no obvious microcracks or porosity, improving weld quality stability by 30%. Compared with traditional welding processes, the intelligent detection system in this embodiment improves the ability to identify weld defects, achieving a welding pass rate of over 96%, reducing the welding rework rate by 50%, and reducing material waste in the production process. Through precise welding path control and an optimized worm gear positioning system, welding time is shortened by 25%, and overall production efficiency is increased by 35%. Simultaneously, the friction stir welding method of this invention has lower energy consumption, reducing power consumption by 22% compared to fusion welding technology, and extending equipment lifespan by 45%, making it suitable for the high-reliability, high-efficiency aerospace manufacturing requirements.

[0112] All aspects not detailed in this invention are conventional technical means known to those skilled in the art.

[0113] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0114] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A friction stir spot welding device for thin-walled aluminum alloy cabins, characterized in that, include: Two spaced-apart bearing supports (1) are used to support the main body of the device; The roller assembly (14) is rotatably connected between two bearing supports (1). The roller assembly (14) includes a reducer mounting shaft (31), a shaft (32), a small flange (33), a positioning plate (34), a cone (35), and a large flange (36). The small end of the cone (35) is fixed by the small flange (33), and the large end is fixed by the large flange (36). The speed reduction drive mechanism includes a worm gear reducer (6), which is fixed to a bearing support (1) on one side by a reducer bracket (5) and is connected to the roller assembly (14) for controlling the welding path; The wedge-shaped self-locking clamping mechanism includes a flange (11) and a support plate (13). The flange (11) is bolted to the support plate (13) and is used to clamp the welded workpiece. The roller assembly (14) and the support plate (13) are wedge-shaped and the cone angle of the wedge-shaped fit is 6°. Spot welding tool (17) for performing friction stir spot welding operations; The visual inspection system (18) acquires solder joint images through a high-resolution industrial camera and automatically judges the surface quality of the solder joints using computer image processing algorithms; The speed reduction drive mechanism also includes a handwheel (8), which is connected to the input end of the worm gear reducer (6) and is used for manual drive adjustment; The flange (11) includes a top plate (28), a reinforcing rib (29) and a ring (30). The flange (11) is connected to the support plate (13) by a round nut (10) and bolts (12). The axial position of the flange (11) can be adjusted by adjusting the position of the round nut (10) on the shaft (32). The steps for spot welding using the aforementioned aluminum alloy thin-walled chamber friction stir spot welding device include: Step S1: Clean the surface of the welding area of ​​the aluminum alloy thin-walled chamber to remove oxide film and impurities; Step S2: Clamp the cabin skin (15) and cabin frame (16) using the wedge self-locking clamping mechanism. Step S3: Adjust the position of the roller assembly (14) using the worm gear reducer (6) to accurately position the welding points; Step S4: Start the spot welding tool (17), set the rotation speed to 2000-3500 rpm, the indentation to 1.2-2.2 mm, and the welding time to 3.0-5.0 seconds / point, and perform friction stir spot welding; Step S5: Allow the material to cool naturally after welding, and keep it clamped to prevent deformation; Step S6: Use a visual inspection system (18) to perform quality analysis on the solder joints. If the solder joints pass the quality inspection, proceed to the next solder joint. In step S4, when the welding material is 2219-T851 aluminum alloy, the rotation speed is set to 2800-2900 rpm, the indentation is 1.8-2.0 mm, and the welding time is 4.0-4.2 seconds / point. In step S4, when the welding material is 2195-T84 aluminum-lithium alloy, the rotation speed is set to 2950-3050 rpm, the indentation is 1.2-1.5 mm, and the welding time is 3.5-3.8 seconds / point.

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