A robot mirror shaping device and method with a local constraint mechanism

Abstract

The present invention provides a robot mirror forming device and method with a local constraint mechanism, belonging to the technical field of metal component forming manufacturing. The device includes a mirror forming processing system, a blank fixing tooling system, a moving constraint block blank holding system, and a device coordinated motion control system. Among them, the mirror forming processing system controls the forming loading tool to work through a six-degree-of-freedom robotic arm; the blank fixing tooling system stabilizes the metal sheet blank; the moving constraint block blank holding system realizes the multi-directional movement of the constraint block and heats the metal sheet blank by means of motors, guide rails, etc.; the device coordinated motion control system ensures the coordinated operation of each part. The method includes solution treatment of the blank, tooling positioning and blank heating, hot forming of the blank, and aging treatment of the preformed part, and finally obtains a metal formed component. The present invention solves the problems of low precision, easy collapse and cracking, high production cost, and uncontrollable tissue properties in the forming of complex local small features of thin-walled metal sheets in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of metal component forming manufacturing, and in particular to a robot mirror forming device and method with a local constraint mechanism. Background Art

[0002] In the field of metal component forming manufacturing, especially in the manufacturing of high-end aerospace equipment, the demand for high-strength aluminum alloy thin-walled components is increasing day by day. Such components are key parts for realizing the lightweight of aerospace equipment and improving the structural stiffness. Taking the bomb bay door of the fourth-generation aircraft as an example, when it is opened and bombed during supersonic cruise, it needs to withstand extremely high aerodynamic loads, which requires the thin-walled components to have extremely high structural stiffness. For this reason, 7xxx series high-strength aluminum alloy is often used for manufacturing. However, the components made of this material have the characteristics of a wall thickness of only 2 mm, complex structures with complex small features, a small round-corner ratio (the ratio of the radius to the round corner r / t ≤ 5), and a high convexity-to-thickness ratio (the ratio of the height to the thickness H / t ≥ 15). The coupling of the structure and the material makes the forming extremely difficult.

[0003] At present, there are many problems with traditional forming methods when dealing with such complex thin-walled components. Paired steel die forming, as the first-generation forming technology for thin-walled components, forms a metal thin plate through two concave and convex dies and is used to manufacture large-size aluminum alloy lightweight thin-walled components. However, this method has poor adaptability to the material properties of 7xxx series high-strength aluminum alloy. At room temperature, the plastic deformation ability of this material is limited, and the elongation rate is low during cold forming. When the component has a small curvature radius or local convex features, the material flow is blocked, and stress concentration is likely to occur, resulting in microscopic cracks or even macroscopic cracking defects. Moreover, after semi-hard forming, subsequent heat treatment is required to achieve the T6 state strength target. However, the residual stress generated due to uneven die constraint during the forming process is superimposed with the phase transformation stress during heat treatment, which will cause shape distortion. For asymmetric thin-walled structures, warping deformation is difficult to eliminate through the straightening process, seriously affecting the assembly accuracy. In addition, steel die forming depends on the matching of fixed cavities, cannot adjust the local pressure distribution in real time, lacks an adaptive compensation mechanism, is prone to uneven wall thickness or surface wrinkles, and is difficult to precisely control the tissue properties and dimensional accuracy, and cannot meet the requirements of high reliability and overall development of high-end equipment for components.

[0004] The single-mode internal high-pressure forming technology belongs to the second-generation forming technology. During the forming process, extremely high hydraulic loads need to be applied. Especially in the area of local fine features of components (such as the ratio of local feature radius to wall thickness r / t ≤ 3), in order to ensure that the material completely fills the mold, large hydraulic equipment with a capacity of ten thousand tons is often required. This not only leads to huge equipment investment and significantly increased energy consumption during the production process, but also causes stress concentration phenomena in local areas of the mold and materials, resulting in uneven local plastic deformation, which may lead to defects such as microcracks and large residual stresses in the forming area, reducing the overall performance and service life of the parts. At the same time, the temperature rises relatively fast in hydraulic forming, and the friction and thermal effects generated under high loads will also have an adverse impact on the material properties, increasing the risks of part thermal deformation and mold wear.

[0005] The mirror forming technology uses a rigid single point and a mirror elastic die to load cooperatively. With the help of the robot trajectory, complex component shapes can be formed. It can form a three-dimensional stress field at the local contact, and use the normal stress to cross the necking bottleneck of two-dimensional stress deformation, significantly improving the forming force. This technology does not require the design and manufacture of molds, can reduce the forming process cost, and can adjust the process parameters in real time during the forming process to ensure the precise forming of complex local small features of thin-walled components. However, during the forming process of large-sized overall reinforced thin-walled components, the sheet metal around the local feature forming will collapse, resulting in a large deviation between the forming accuracy of the overall component and the expectation; in addition, it is relatively difficult to perform hot forming after the overall heat treatment of the large-area slab, and the dimensional accuracy of the finally formed component is poor.

[0006] In summary, the existing forming methods generally have problems such as low production efficiency, low forming accuracy, and weak component performance, and none of them can meet the forming requirements of thin-walled complex components in the aerospace field. Summary of the Invention

[0007] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a robot mirror forming device and method with a local constraint mechanism, which solves the problems of low accuracy, easy collapse and cracking, high production cost, and uncontrollable tissue performance during the forming of complex local small features of thin-walled metal sheets in the prior art, and realizes the integrated forming of shape and property control of thin-walled metal sheets with high precision, high performance, and low cost.

[0008] To achieve the above purpose, the present invention provides the following solutions:

[0009] A robot mirror forming device with a local constraint mechanism, comprising a mirror forming processing system, a blank fixing tooling system, a moving constraint block blank holding system, and a device collaborative motion control system; the blank fixing tooling system is respectively arranged at both ends of a metal sheet blank, and the mirror forming processing system is located on both sides of the blank fixing tooling system, and is used for mirror forming processing of the metal sheet blank fixed on the blank fixing tooling system; the moving constraint block blank holding system is arranged around the corresponding blank fixing tooling system, and is used for applying local constraints to the edge of the metal sheet blank to prevent the metal sheet blank from displacing and deforming during the processing; the device collaborative motion control system is respectively connected to the mirror forming processing system, the blank fixing tooling system, and the moving constraint block blank holding system, and is used for controlling the collaborative work of each system to ensure the efficient and stable operation of the entire device.

[0010] Preferably, the two groups of the mirror forming processing systems include six-degree-of-freedom robotic arms, forming loading tools, cameras, and support blocks; the two six-degree-of-freedom robotic arms are symmetrically arranged, the two forming loading tools are respectively connected to the ends of the corresponding six-degree-of-freedom robotic arms, the six-degree-of-freedom robotic arms control the rotation of the forming loading tools through motors to realize the forming of the metal sheet blank; the two cameras are respectively connected to one side of the corresponding six-degree-of-freedom robotic arms close to the forming loading tools, and are used for real-time monitoring of the processing conditions; the two support blocks and the forming loading tools are respectively fixedly connected to the corresponding six-degree-of-freedom robotic arms through three-jaw chucks; the forming loading tools contact the metal sheet blank through rotation, and the six-degree-of-freedom robotic arms provide feeds for the corresponding forming loading tools in the X-axis, Y-axis, and Z-axis directions, and the six-degree-of-freedom robotic arm on the other side drives the corresponding support block to perform a follow-up motion; an infrared thermometer is installed on the punch of the mirror forming processing system, and the infrared thermometer is connected to the device collaborative motion control system.

[0011] Preferably, the blank fixing tooling system consists of two groups of fixing mechanisms, and both groups of the fixing mechanisms include bases and fixtures; the fixtures are connected to the bases and are used for fixing the metal sheet blank to ensure that the metal sheet blank maintains a stable position and posture during the processing; the bases provide support for the entire blank fixing tooling system to ensure the stability of the overall device; the clamping surface width of the fixtures is 5-10 cm to adapt to metal sheet blanks of different sizes.

[0012] Preferably, the moving constraint block blank-holding system includes a horizontal cylinder, a heat insulation plate, a constraint block, a resistance heating rod, a moving platform, a slider, a wire cylinder, a coupling, a motor, a motor fixing plate, a guide rail, and a horizontal cylinder fixing plate; the guide rail is connected to the base, the slider is slidably engaged with the guide rail, and the slider is connected to the moving platform to provide a moving basis for the device components; the horizontal cylinder is bolted to the moving platform to provide the movement of the constraint block in the Z-axis direction, and a horizontal cylinder fixing plate is installed on the horizontal cylinder, and the horizontal cylinder fixing plate is connected to another horizontal cylinder by bolts to provide the movement of the constraint block in the Y-axis direction; the heat insulation plate is connected between the horizontal cylinder and the constraint block to isolate the heat generated by the constraint block and prevent the heat from being transferred to the horizontal cylinder and affecting its performance; the constraint block is connected to the output end of the horizontal cylinder and directly acts on the edge of the metal sheet blank to apply a constraint pressure; the resistance heating rod is connected to the constraint block to heat the sheet to be formed through the constraint block; the motor is connected to the motor fixing plate, the motor fixing plate is connected to the base by bolts, the output shaft of the motor is connected to the wire cylinder through a coupling, the wire cylinder cooperates with the slider, and when the motor rotates, it drives the wire cylinder to rotate, thereby driving the slider and the moving platform to move along the guide rail; the power of the resistance heating rod is 1-2 kW.

[0013] Preferably, the device coordinated motion control system includes a central controller, a console, and a cable; the central controller is connected to the mirror forming processing system, the moving constraint block blank-holding system, and the blank fixing tooling system through the cable respectively, and is used to receive the feedback information of each system and issue control instructions according to a preset program to coordinate the actions of each system. The cable uses a shielded cable to reduce signal interference; the console is connected to one side of the central controller and is used for the operator to input control instructions, set processing parameters, and motion trajectories.

[0014] The present invention also provides a forming method using the above-mentioned robot mirror forming device with a local constraint mechanism, including the following steps:

[0015] S1. Use a heating furnace to perform solution treatment and heat preservation on the metal sheet blank to obtain a uniform and good-plastic microstructure, and then transfer it to room-temperature clear water to cool to room temperature;

[0016] S2. Fix the cooled metal sheet blank to the blank fixing tooling system, move the constraint block to be close to the blank through the moving constraint block blank-holding system, and use the resistance heating rod in the constraint block to heat the metal sheet blank to the target temperature;

[0017] S3. After the metal sheet blank is heated to the target temperature, the moving platform drives the restraint blocks to move to both sides of the heating area, and the horizontal cylinders push the restraint blocks to press the blank tightly, applying a blank-holding force. Subsequently, the robot trajectory is planned through the device collaborative motion control system, and the forming loading tool of the mirror forming processing system is controlled to perform hot forming on the heating area to form complex local small features.

[0018] S4. Repeat S3 until the forming of all complex small features is completed. Subsequently, the preform is cooled to room temperature, the blank-holding force is unloaded, and the preform is taken out for aging treatment. Finally, the surplus is cut, and a metal formed component is finally obtained.

[0019] Preferably, in S1, the solution treatment temperature of the metal sheet blank is 450 - 500 °C, the solution treatment time is not less than 30 min, the heat preservation time of the metal sheet blank after solution treatment is 20 - 40 min, and the transfer time for transferring the solution-treated metal sheet blank to clear water through the transfer tool is 3 - 10 s.

[0020] Preferably, in S2, the target temperature is 20 - 500 °C.

[0021] Preferably, in S3, the horizontal cylinders push the restraint blocks to press the blank tightly, the applied blank-holding force is 0 - 5 t, the rotation speed of the forming loading tool is 0 - 1000 rpm, the punch feed rate of the mirror forming processing system is 1000 - 2000 mm / min, and the applied forming force is 0 - 5000 N.

[0022] Preferably, in S4, the aging treatment process of the preform is: putting the taken-out preform into an aging furnace at a temperature of 100 - 200 °C for heat preservation, and the heat preservation time is 6 - 36 h.

[0023] According to the specific embodiments provided by the present invention, the following technical effects are disclosed by the present invention:

[0024] (1) The present invention utilizes a collaborative system composed of structures such as a moving platform and restraint blocks to apply a dynamically adjustable blank-holding force around the area to be formed, effectively avoiding the collapse of the sheet during the mirror progressive forming process and reducing the influence on the surrounding sheets; the local heat treatment significantly reduces the material springback rate, thereby significantly improving the forming accuracy.

[0025] (2) During the sheet forming process provided by the present invention, the temperature, rotation speed, feed rate, and forming force magnitude can all be controlled. By optimizing the process parameters, a formed thin-walled part with uniform wall thickness can be obtained; the rigid single-point and mirror elastic die collaborative loading is adopted to form a three-dimensional stress field locally on the blank, improving the forming limit, avoiding the cracking defect during the forming of local protrusions, and the heating operation further improves the formability of the sheet.

[0026] (3) The technical solution provided by the present invention adopts a die - less forming process, eliminating the die - processing link, avoiding the limitations of traditional die forming on the structure, and enabling the processing of complex geometric shapes such as free - form surfaces and thin - walled blades. At the same time, it reduces energy consumption and carbon emissions, conforms to the principle of sustainable development, effectively reduces production costs and production cycles, and has strong processing flexibility.

[0027] (4) By controlling the forming temperature and heating rate of the sheet, the present invention can obtain a good phase distribution and grain size, improving the forming performance. The temperature at different positions can be controlled in zones. According to the performance requirements of different deformation zones of the metal thin - walled component, a gradient structure can be obtained, enabling the metal thin - walled component to have both high formability and customized performance. Brief Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0029] Figure 1 It is a schematic diagram of the overall structure in the XOY direction provided for a robot mirror - image forming device with a local constraint mechanism of the present invention;

[0030] Figure 2 It is a schematic diagram of the structure in the XOZ direction provided for a robot mirror - image forming device with a local constraint mechanism of the present invention;

[0031] Figure 3 It is a schematic diagram of the projection in the horizontal direction of the constraint block and the resistance heating rod provided for a robot mirror - image forming device with a local constraint mechanism of the present invention;

[0032] Figure 4 It is a flowchart of the forming method for a robot mirror - image forming device with a local constraint mechanism of the present invention;

[0033] Figure 5 It is a schematic diagram of the formed part structure provided by the present invention.

[0034] Explanation of the Reference Numerals in the Drawings:

[0035] 1. Mirror forming processing system; 11. Six-degree-of-freedom robotic arm; 12. Forming loading tool; 13. Camera; 14. Support block; 2. Blank fixing tooling system; 21. Base; 22. Fixture; 3. Moving constraint block blank holding system; 31. Horizontal cylinder; 32. Heat insulation plate; 33. Constraint block; 34. Resistance heating rod; 35. Moving platform; 36. Slide block; 37. Wire cylinder; 38. Coupling; 39. Motor; 310. Motor fixing plate; 311. Guide rail; 312. Horizontal cylinder fixing plate; 4. Device cooperative motion control system; 41. Central controller; 42. Console; 43. Cable; 5. Metal sheet blank. Detailed implementation manners

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the drawings and specific implementation manners.

[0038] Embodiment 1

[0039] As Figure 1 and Figure 2 shown, the present invention provides a robotic mirror forming device with a local constraint mechanism, including a mirror forming processing system 1, a blank fixing tooling system 2, a moving constraint block blank holding system 3, and a device cooperative motion control system 4; the blank fixing tooling system 2 is respectively arranged at both ends of the metal sheet blank 5, and the mirror forming processing system 1 is located on both sides of the blank fixing tooling system 2 for mirror forming processing of the metal sheet blank 5 fixed on the blank fixing tooling system 2; the moving constraint block blank holding system 3 is arranged around the corresponding blank fixing tooling system 2 for applying local constraints to the edge of the metal sheet blank 5 to prevent the metal sheet blank 5 from shifting and deforming during the processing; the device cooperative motion control system 4 is respectively connected to the mirror forming processing system 1, the blank fixing tooling system 2, and the moving constraint block blank holding system 3 for controlling the coordinated operation of each system to ensure the efficient and stable operation of the entire device.

[0040] According to the above content, the two groups of mirror forming processing systems 1 include a six-degree-of-freedom robotic arm 11, a forming loading tool 12, a camera 13, and a support block 14; the two six-degree-of-freedom robotic arms 11 are symmetrically arranged, and the two forming loading tools 12 are respectively connected to the ends of the corresponding six-degree-of-freedom robotic arms 11. The six-degree-of-freedom robotic arm 11 controls the rotation of the forming loading tool 12 through a motor 39 to achieve the forming of the metal sheet blank 5; the two cameras 13 are respectively connected to one side of the corresponding six-degree-of-freedom robotic arm 11 close to the forming loading tool 12 for real-time monitoring of the processing situation; the two support blocks 14 and the forming loading tool 12 are respectively fixedly connected to the corresponding six-degree-of-freedom robotic arms 11 through three-jaw chucks; the forming loading tool 12 contacts the metal sheet blank 5 through rotation, and the six-degree-of-freedom robotic arm 11 provides feeds for the corresponding forming loading tool 12 in the X-axis, Y-axis, and Z-axis directions, and the six-degree-of-freedom robotic arm 11 on the other side drives the corresponding support block 14 to perform a following movement; an infrared thermometer is installed on the punch of the mirror forming processing system 1, and the infrared thermometer is connected to the device cooperative motion control system 4. When hot forming, the materials of the forming loading tool 12 and the support block 14 on the back can be selected from common die materials for hot forming, such as low-carbon steel, stainless steel, Ni7N, etc. At the same time, asbestos is wound outside to reduce the convective and radiative heat transfer between the die and the external environment during the heat transfer process and improve the temperature uniformity of the die; when the forming temperature is room temperature, the material of the support block 14 on the back of the forming loading tool 12 can be selected as polyurethane elastomer. In addition, the forming loading tool 12 can be selected as a ball-shaped tool, and its size is selected according to specific processing characteristics. The geometric shape of the contact area of the forming recording tool is the tip of a spherical tool and is circular.

[0041] The blank fixing tooling system 2 consists of two groups of fixing mechanisms, and both groups of fixing mechanisms include a base 21 and a fixture 22; the fixture 22 is connected to the base 21 and is used to fix the metal sheet blank 5 to ensure that the metal sheet blank 5 maintains a stable position and posture during the processing; the base 21 provides support for the entire blank fixing tooling system 2 to ensure the overall stability of the device; the clamping surface width of the fixture 22 is 5 - 10 cm to adapt to metal sheet blanks 5 of different sizes.

[0042] The moving constraint block blank-holding system 3 includes a horizontal cylinder 31, a heat insulation plate 32, a constraint block 33, a resistance heating rod 34, a moving platform 35, a slider 36, a wire cylinder 37, a coupling 38, a motor 39, a motor fixing plate 310, a guide rail 311, and a horizontal cylinder fixing plate 312; the guide rail 311 is connected to the base 21, the slider 36 is slidably engaged with the guide rail 311, and the slider 36 is connected to the moving platform 35 to provide a moving basis for the device components; the horizontal cylinder 31 is bolted to the moving platform 35 and is used to provide the movement of the constraint block 33 in the Z-axis direction. A horizontal cylinder fixing plate 312 is installed on the horizontal cylinder 31, and the horizontal cylinder fixing plate 312 is connected to another horizontal cylinder 31 by bolts to provide the movement of the constraint block 33 in the Y-axis direction; the heat insulation plate 32 is connected between the horizontal cylinder 31 and the constraint block 33 and is used to isolate the heat generated by the constraint block 33 to prevent the heat from being transferred to the horizontal cylinder 31 and affecting its performance; the constraint block 33 is connected to the output end of the horizontal cylinder 31 and directly acts on the edge of the metal sheet blank 5 to apply a constraint pressure; referring to Figure 3 , the resistance heating rod 34 is connected to the constraint block 33 to heat the sheet to be formed through the constraint block 33; the motor 39 is connected to the motor fixing plate 310, the motor fixing plate 310 is connected to the base 21 by bolts, the output shaft of the motor 39 is connected to the wire cylinder 37 through the coupling 38, and the wire cylinder 37 cooperates with the slider 36. When the motor 39 rotates, it drives the wire cylinder 37 to rotate, thereby driving the slider 36 and the moving platform 35 to move along the guide rail 311; the power of the resistance heating rod 34 is 1 - 2 kW.

[0043] In the above structure, the horizontal cylinder 31 selects a servo telescopic cylinder, including but not limited to an electric telescopic cylinder and a pneumatic telescopic cylinder, to ensure the accurate stroke of the constraint block 33. And the material of the constraint block 33 is selected from common die materials for hot forming, such as low-carbon steel, stainless steel, Ni7N, etc., to ensure the provision of an appropriate blank-holding force. The material of the heat insulation plate 32 is selected from asbestos board, fireproof board, etc. to prevent the heat from being transferred to the horizontal cylinder 31 and the device, avoiding the damage of the device. The motor 39 selects a servo motor or an oil cylinder to ensure the movement of the constraint block 33.

[0044] The device coordinated motion control system 4 includes a central controller 41, a console 42, and a cable 43; the central controller 41 is respectively connected to the mirror forming processing system 1, the moving constraint block blank-holding system 3, and the blank fixing tooling system 2 through the cable 43, and is used to receive the feedback information of each system and issue control instructions according to the preset program to coordinate the actions of each system. The cable 43 uses a shielded cable to reduce signal interference; the console 42 is connected to one side of the central controller 41 and is used for the operator to input control instructions, set processing parameters, and motion trajectories.

[0045] Embodiment 2

[0046] Referring to Figure 4, this embodiment provides a forming method using the robot mirror forming device with a local constraint mechanism described in Embodiment 1, including the following steps:

[0047] S1. Use a heating furnace to perform solution treatment on the metal sheet blank and keep it warm to obtain a uniform and good-plastic microstructure, and then transfer it to room-temperature clear water to cool it to room temperature;

[0048] S2. Fix the cooled metal sheet blank to the blank fixing tooling system, move the constraint block blank holding system to make the constraint block move close to the blank, and use the resistance heating rod in the constraint block to heat the metal sheet blank to the target temperature;

[0049] S3. After the metal sheet blank is heated to the target temperature, the moving platform drives the constraint block to move to both sides of the heating area, the horizontal cylinder pushes the constraint block to press the blank and apply a blank holding force; then, plan the robot trajectory through the device coordinated motion control system, and control the forming loading tool of the mirror forming processing system to perform hot forming on the heating area to form complex local small features;

[0050] S4. Repeat S3 until all complex small features are formed, then cool the preform to room temperature, unload the blank holding force, take out the preform for aging treatment, and finally cut the surplus to finally obtain a metal formed component.

[0051] Among them, in S1, the solution treatment temperature of the metal sheet blank is 450 - 500 °C, the solution time is not less than 30 min, the heat preservation time of the metal sheet blank after solution treatment is 20 - 40 min, and the transfer time for transferring the solution-treated metal sheet blank to clear water through the transfer tool is 3 - 10 s. The purpose is to make the alloying elements evenly distributed in the metal matrix. The metal sheet blank here can be selected as 7xxx series aluminum alloy, and the temperature is in the most suitable range to avoid overburning of the microstructure due to too high temperature. In S2, the target temperature is 20 - 500 °C. In S3, the horizontal cylinder pushes the constraint block to press the blank, and the applied blank holding force is 0 - 5 t, which can effectively prevent local collapse during the mirror progressive forming process and avoid affecting the forming progress. The rotation speed of the forming loading tool is 0 - 1000 rpm, the punch feed rate of the mirror forming processing system is 1000 - 2000 mm / min, and the applied forming force is 0 - 5000 N. In S4, the aging treatment process of the preform is: put the taken-out preform into an aging furnace at a temperature of 100 - 200 °C for heat preservation, and the heat preservation time is 6 - 36 h.

[0052] Embodiment 3

[0053] In this embodiment, taking the high-strength aluminum alloy 7075 with a wall thickness of 2 mm as an example, the device provided in Embodiment 1 and the forming method of Embodiment 2 are used for further verification, which specifically includes the following steps:

[0054] Step 1: Solution treatment of the high-strength aluminum alloy 7075 in a high-temperature heating furnace; first, raise the temperature of the environmental heating furnace to 457 °C, with a solution time of 30 min. Then, after the solution treatment is completed, keep the furnace at a constant temperature for 30 min to make the alloying elements evenly distributed in the aluminum matrix. Finally, after the heat preservation is completed, quickly transfer the blank to clean water for cooling through a transfer tool, and the cooling time is not less than 5 min.

[0055] Step 2: Mount the blank tooling after solution treatment in the device frame provided in Embodiment 1, use the moving platform to drive the constraint block to clamp the blank, and heat the high-strength aluminum alloy 7075 blank to 450 °C.

[0056] Step 3: After the high-strength aluminum alloy 7075 blank is heated to 450 °C, the moving platform drives the constraint block to move to the heating area, and the horizontal cylinder pushes the constraint block to press the blank, providing a blank holding force of 0 - 5 t, thereby preventing local collapse during the forming process and avoiding affecting the forming accuracy. Subsequently, plan the robot trajectory through the device collaborative motion control system, and control the forming loading tool of the mirror forming processing system to move along the surface of the blank for forming. During the forming process, the rotation speed of the forming loading tool is 250 rpm, the punch feed rate is 1000 mm / min, and the forming force range that the two-side mirror forming processing system can provide is 0 - 5000 N.

[0057] Step 4: Repeat Step 3 until the forming of all complex small features is completed. Then, unload the blank holding force, remove the device, take out the preformed component and put it into an aging furnace for aging treatment. The aging temperature of the high-strength aluminum alloy 7075 is 120 °C, and the aging time is 18 h. Cut the forming area and the surplus to complete the forming manufacturing of the large-size aluminum alloy lightweight thin-walled component.

[0058] Refer to Figure 5 As shown, it can be inferred from the four parts formed by the above method and device that they have similar frame contour shapes, which further illustrates that the robot mirror forming device with a local constraint mechanism can machine such components with complex outer shapes, demonstrating the ability of this device to process various shapes in the forming of thin-walled metal sheets, and showing the feasibility and versatility of its application in actual production for manufacturing parts with similar structural features.

[0059] Therefore, by adopting the above-mentioned robot mirror forming device and method with a local constraint mechanism, the problems in the prior art, such as low precision, easy collapse and cracking, high production cost, and uncontrollable tissue properties during the forming of complex local small features of thin-walled metal sheets, are solved, and the integrated forming of shape and property control of thin-walled metal sheets with high precision, high performance, and low cost is realized.

[0060] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same and similar parts among the various embodiments, reference can be made to each other.

[0061] Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A robot mirror forming device with a local constraint mechanism, characterized in that, It includes a mirror forming processing system, a blank fixing tooling system, a moving restraint block blank holding system, and a device coordinated motion control system; the blank fixing tooling system is respectively arranged at both ends of the metal sheet blank, and the mirror forming processing system is located on both sides of the blank fixing tooling system for mirror forming processing of the metal sheet blank fixed on the blank fixing tooling system; the moving restraint block blank holding system is arranged around the corresponding blank fixing tooling system for applying local restraint to the edge of the metal sheet blank to prevent displacement and deformation of the metal sheet blank during the processing; the device coordinated motion control system is respectively connected to the mirror forming processing system, the blank fixing tooling system, and the moving restraint block blank holding system for controlling the coordinated operation of each system to ensure the efficient and stable operation of the entire device; The moving restraint block blank holding system includes a horizontal cylinder, a heat insulation plate, a restraint block, a resistance heating rod, a moving platform, a slider, a lead screw cylinder, a coupling, a motor, a motor fixing plate, a guide rail, and a horizontal cylinder fixing plate; the guide rail is connected to the base, the slider is slidably matched with the guide rail, and the slider is connected to the moving platform to provide a moving basis for the device components; the horizontal cylinder is bolted to the moving platform for providing the movement of the restraint block in the Z-axis direction, and a horizontal cylinder fixing plate is installed on the horizontal cylinder, and the horizontal cylinder fixing plate is connected to another horizontal cylinder by bolts for providing the movement of the restraint block in the Y-axis direction; the heat insulation plate is connected between the horizontal cylinder and the restraint block for isolating the heat generated by the restraint block to prevent heat transfer to the horizontal cylinder and affecting its performance; the restraint block is connected to the output end of the horizontal cylinder and directly acts on the edge of the metal sheet blank to apply a restraint pressure; the resistance heating rod is connected to the restraint block for heating the sheet to be formed through the restraint block; the motor is connected to the motor fixing plate, the motor fixing plate is connected to the base by bolts, the output shaft of the motor is connected to the lead screw cylinder through a coupling, the lead screw cylinder is matched with the slider, and when the motor rotates, it drives the lead screw cylinder to rotate, thereby driving the slider and the moving platform to move along the guide rail; the power of the resistance heating rod is 1-2 kW.

2. The robot mirror forming device with a local constraint mechanism according to claim 1, wherein The two sets of the mirror forming processing systems include six-degree-of-freedom robotic arms, forming loading tools, cameras, and support blocks; the two six-degree-of-freedom robotic arms are symmetrically arranged, and the two forming loading tools are respectively connected to the ends of the corresponding six-degree-of-freedom robotic arms. The six-degree-of-freedom robotic arms control the rotation of the forming loading tools through motors to achieve the forming of metal sheet blanks; the two cameras are respectively connected to one side of the corresponding six-degree-of-freedom robotic arms close to the forming loading tools for real-time monitoring of the processing conditions; the two support blocks and the forming loading tools are respectively fixedly connected to the corresponding six-degree-of-freedom robotic arms through three-jaw chucks; the forming loading tools are in contact with the metal sheet blanks through rotation, and the six-degree-of-freedom robotic arms provide feeds for the corresponding forming loading tools in the X-axis, Y-axis, and Z-axis directions, and the six-degree-of-freedom robotic arm on the other side drives the corresponding support block to move in a follow-up manner; an infrared thermometer is installed on the punch of the mirror forming processing system, and the infrared thermometer is connected to the device collaborative motion control system.

3. The robot mirror forming device with a local constraint mechanism according to claim 1, characterized in that, The blank fixing tooling system consists of two sets of fixing mechanisms, and both sets of the fixing mechanisms include bases and clamps; the clamps are connected to the bases and are used to fix the metal sheet blanks to ensure that the metal sheet blanks maintain stable positions and postures during the processing; the bases provide support for the entire blank fixing tooling system to ensure the overall stability of the device; the clamping surface width of the clamps is 5 - 10 cm to adapt to metal sheet blanks of different sizes.

4. A robot mirror forming device with a local constraint mechanism according to claim 1, characterized in that, The device collaborative motion control system includes a central controller, a console, and cables; the central controller is respectively connected to the mirror forming processing system, the moving restraint block blank holding system, and the blank fixing tooling system through cables, and is used to receive the feedback information of each system and issue control instructions according to a preset program to coordinate the actions of each system. The cables use shielded cables to reduce signal interference; the console is connected to one side of the central controller and is used for operators to input control instructions, set processing parameters, and motion trajectories.

5. A forming method of a robot mirror forming device with a local constraint mechanism according to any one of claims 1 to 4, characterized in that, It includes the following steps: S1. Use a heating furnace to perform solution treatment on the metal sheet blank and keep it warm to obtain a uniform and plastically good microstructure, and then transfer it to room-temperature clear water for cooling to room temperature. S2. Fix the cooled metal sheet blank to the blank fixing tooling system, move the restraint block to be close to the blank through the moving restraint block blank holding system, and use the resistance heating rod in the restraint block to heat the metal sheet blank to the target temperature. S3. After the metal sheet blank is heated to the target temperature, the moving platform drives the restraint block to move to both sides of the heating area, and the horizontal cylinder pushes the restraint block to press the blank to apply a blank holding force; then, plan the robot trajectory through the device collaborative motion control system, and control the forming loading tool of the mirror forming processing system to perform hot forming on the heating area to form complex local small features. S4. Repeat S3 until all complex small features are formed, then cool the preformed part to room temperature, unload the blank holding force, take out the preformed part for aging treatment, and finally cut the surplus to finally obtain the metal formed component.

6. The forming method of a robot mirror forming device with a local constraint mechanism according to claim 5, characterized in that, In S1, the solution treatment temperature of the metal sheet blank is 450 - 500 °C, the solution time is not less than 30 min, the holding time of the metal sheet blank after solution treatment is 20 - 40 min, and the transfer time for transferring the solution-treated metal sheet blank to clean water through a transfer tool is 3 - 10 s.

7. The forming method of a robot mirror forming device with a local constraint mechanism according to claim 5, characterized in that, In S2, the target temperature is 20 - 500 °C.

8. The forming method of a robot mirror forming device with a local constraint mechanism according to claim 5, characterized in that In S3, the horizontal cylinder pushes the restraint block to press the blank, the applied blank holding force is 0 - 5 t, the rotation speed of the forming loading tool is 0 - 1000 rpm, the punch feed rate of the mirror forming processing system is 1000 - 2000 mm / min, and the applied forming force is 0 - 5000 N.

9. The forming method of a robot mirror forming device with a local constraint mechanism according to claim 5, characterized in that, In S4, the aging treatment process of the preform is as follows: The taken-out preform is put into an aging furnace at a temperature of 100 - 200 °C for heat preservation, and the heat preservation time is 6 - 36 h.

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