Self-adaptive machining tooling and self-adaptive machining method for complex frame type thin-walled part

Abstract

The application provides a self-adaptive machining tool for a complex frame type thin-wall workpiece, which comprises a workpiece profiling position, a fixing part, a driving mechanism installed in a groove in the workpiece profiling position, and a compensation mechanism installed in the workpiece profiling position, wherein a contact block of the compensation mechanism is in contact with an internal rib structure of the workpiece, and a lower end surface of the compensation mechanism is connected with the driving mechanism, and the driving mechanism drives the compensation mechanism to displace, so as to self-adaptively compensate the vibration and deformation of the workpiece generated in the milling and welding process. The application can improve the clamping rigidity of the easily-deformed structure of the complex frame type thin-wall workpiece, reduce the milling vibration and deformation, and the problems such as the missing welding and the welding separation, and improve the machining quality.

Description

Technical Field

[0001] This invention relates to the field of thin-walled part processing technology, specifically to an adaptive machining fixture and adaptive machining method for complex frame-type thin-walled parts. Background Technology

[0002] Machining thin-walled parts has long been a challenging problem in the machining field. With the increasing market demand for small-batch, high-variety thin-walled parts, the costs of fixtures and machining are bound to rise. Complex frame-type thin-walled parts are widely used in load-bearing structural components of aerospace products such as stars, rockets, and missiles. However, these parts have complex structures, low rigidity, and are difficult to position. Furthermore, milling and welding processes are prone to deformation and chatter, making it difficult to meet machining accuracy requirements.

[0003] Currently, the main clamping methods used in machining thin-walled frame parts are as follows: The first method is to use an oil film to create a vacuum for clamping. During the clamping process, firstly, machine oil is evenly applied to the upper end face of the sliding positioning plate in the mounting groove of the fixture. Then, the thin-walled frame part is flattened against the end face of the sliding positioning plate, and pressure is evenly applied longitudinally to the upper end face of the thin-walled frame part to expel the air between the thin-walled frame part and the sliding plate, creating a vacuum. Thus, the atmospheric pressure generated by the oil suction and the surface tension of the machine oil are used to adhere the thin-walled frame part to the sliding positioning plate. For example, Chinese Patent CN113953545A discloses an auxiliary support vibration damping device for turning small-diameter thin-walled pipe fittings, including a mandrel. One end of the mandrel is a connecting part, which is used to connect with the workpiece clamp. The other end of the mandrel is a first sealing part. A second sealing part is provided on the mandrel section between the first sealing part and the connecting part. The mandrel section between the second sealing part and the first sealing part is a support part. The first sealing part and the second sealing part are used to cooperate with the inner wall of the workpiece to form a seal. A grease film is formed between the first sealing part, the second sealing part, the support part, and the inner wall of the workpiece. The disadvantages of this clamping method are: (1) machine oil easily causes pollution to the system equipment, resulting in high cost and environmental problems; (2) since the thin-walled frame parts are tightly attached to the sliding positioning plate, rough machining of the parts cannot be achieved.

[0004] The second method is to use the vacuum generated by the vacuum suction cup to clamp thin-walled frame parts. Before clamping, the vacuum pump unit is connected to the suction cup of the clamping body, and then the part to be clamped is clamped on the vacuum pump suction cup of the clamping body. After confirming that the clamping is in place, the vacuum pump unit is turned on to enter the working state. For example, Chinese patent with publication number CN115741181A discloses a vacuum clamping fixture for arc-shaped thin-walled parts. The air in the closed space between the arc-shaped positioning plate and the arc-shaped thin-walled part is extracted by the vacuum pumping chamber. The air pressure is used to press and fix the thin-walled arc-shaped part on the arc-shaped positioning plate, and the part is locked by the combined pressure plate. The disadvantages of this clamping method are: (1) First, the vacuum generated by the atmosphere is used to clamp the part, which requires very high surface quality of the part blank; (2) This clamping method cannot achieve the positioning and clamping of the fixture in one go. Other accessories need to be added, and the fixture adjustment time is long; (3) The clamping force is difficult to control, and the shape of the thin-walled part is greatly restricted.

[0005] The third method involves using traditional clamping techniques. This involves optimizing the clamping scheme within the clamping device, using traditional jigs to clamp specific points on the outer edge of thin-walled frame parts. While simple, this method has significant drawbacks: traditional jigs, unable to control clamping force, easily deform thin-walled frame parts, leading to substantial machining accuracy errors. During machining, rib structures are prone to significant cutting chatter and deformation; in welding, the skin is mostly fixed manually, resulting in poor positioning accuracy, low machining efficiency, and an inability to guarantee welding quality, easily leading to incomplete welds or weld detachment.

[0006] In order to solve the problems of low flexibility, difficulty in controlling clamping force and difficulty in positioning of the above-mentioned clamping devices for thin-walled frame parts, there is an urgent need to provide a clamping device for processing thin-walled frame parts, especially for clamping devices for complex thin-walled frame parts. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide an adaptive machining fixture and adaptive machining method for complex frame-type thin-walled parts.

[0008] To achieve the above and other objectives, the present invention is implemented through the following technical solution: First, an adaptive machining fixture for complex frame-type thin-walled parts is provided, including workpiece contouring positions, which are identical in shape to the workpiece, and at least two of the workpiece contouring positions are mirror-image arranged on a base; a fixing member is installed on the base near the workpiece contouring positions for fixing the workpiece; a driving mechanism is installed in a groove in the workpiece contouring position; a compensation mechanism is installed in the workpiece contouring position, and the contact block of the compensation mechanism contacts the internal rib structure of the workpiece; the lower end face of the compensation mechanism is connected to the driving mechanism, and the driving mechanism drives the compensation mechanism to move, thereby compensating for chatter and deformation generated in the workpiece during milling and welding.

[0009] In one embodiment, the compensation mechanism includes a contact block and a push rod. The contact block is mounted on the end of the push rod, and the push rod causes the contact block to move, serving as a support for the internal structure of the workpiece.

[0010] In one embodiment, a first thin-film force sensor and a piezoelectric ceramic sheet are mounted on the end face of the contact block that contacts the workpiece, respectively for detecting the pressure and chatter deformation of the workpiece.

[0011] In one embodiment, the end face of the contact block that contacts the workpiece is a nitrile rubber layer.

[0012] In one embodiment, the drive mechanism includes a piezoelectric ceramic stack, a contact head, and a linkage assembly. The linkage assembly is connected to the piezoelectric ceramic stack via the contact head, which is mounted on the displacement output end of the piezoelectric ceramic stack.

[0013] In one embodiment, the linkage assembly includes a first link, a second link, and a connecting push rod, wherein the input end of the second link is connected to the output end of the first link via the connecting push rod.

[0014] In one embodiment, the fastener includes an external fastener and an internal fastener. The external fastener is arranged around the outer periphery of the workpiece contouring position to fix the upper end face of the workpiece. The internal fastener is installed inside the workpiece contouring position to fix and support the internal structure of the workpiece.

[0015] In one embodiment, the external fixing component is a corner clamping cylinder, and the internal fixing component is a pneumatic expansion clamp and a pneumatic gripper. The pneumatic expansion clamp acts on the inner wall of the workpiece, and the pneumatic gripper acts on the internal rib structure of the workpiece.

[0016] In one embodiment, the workpiece conformal positioning includes a mounting boss, the shape of which matches the shape of the workpiece, and when the workpiece is placed in the mounting boss, the workpiece fits against the mounting boss.

[0017] In one embodiment, the height of the mounting boss is greater than the thickness of the workpiece.

[0018] In one embodiment, the workpiece contouring further includes a positioning boss, which is disposed within the mounting boss and is fitted to the position of a special shape inside the workpiece to achieve precise positioning of the workpiece.

[0019] This invention also provides an adaptive machining method for complex frame-type thin-walled parts, comprising the following steps:

[0020] Step S1: Install and secure the workpiece;

[0021] Step S11: Install the workpiece by placing it inside the mounting boss and precisely positioning it using the positioning boss.

[0022] Step S12: Coarsely adjust the adaptive compensation unit by controlling the push rod and contact block to extend and displace towards both ends, and coarsely adjust the support distance of the adaptive compensation unit;

[0023] Step S13: Fix the workpiece: The external fixing component and the internal fixing component are controlled by the control module to fix the upper end face, inner wall and rib structure of the workpiece respectively;

[0024] Step S14: Control the adaptive compensation unit to provide precise support, drive the adaptive compensation unit to continue to move, and when the first thin-film force sensor on the end face of the contact block detects a pressure signal, it indicates that the adaptive compensation unit is in place;

[0025] Step S2: Mill the front side of the workpiece 2;

[0026] Step S3: Weld the front side of the workpiece 2;

[0027] Step S31: Install the welding parts, reverse control the external fixing parts to detach from the upper end face of the workpiece, and place the skin and cover plate to be welded on the upper end of the workpiece.

[0028] Step S32: Fix the welded parts and control the external fixing parts to press the upper end face of the cover plate until the second force sensor installed at the lower end of the cover plate detects the pressure signal;

[0029] Step S33: Spot welding process, spot welding process is performed on the skin through the gun groove on the cover plate;

[0030] Step S34: Full welding process, control the external fastener to detach from the upper end face of the cover plate, disassemble the cover plate, and perform full welding process on the skin;

[0031] Step S4: Monitor flutter and deformation online, and adaptively compensate for flutter and deformation;

[0032] By monitoring and collecting the chatter and deformation signals of the workpiece using a piezoelectric ceramic sheet, the adaptive compensation unit is controlled to output displacement, and the amount of support provided by the adaptive compensation unit to the workpiece is adjusted online.

[0033] Step S5: Mill and weld the reverse side of workpiece 2, control the external fastener and the internal fastener to loosen the workpiece, flip the workpiece and place it in another mounting boss set in a mirror image, and then repeat the above steps S1 to S4.

[0034] Step S4 is performed simultaneously with step S2.

[0035] Furthermore, in step S3, the shape of the cover plate is completely consistent with the shape of the workpiece.

[0036] Furthermore, in step S3, a flexible layer is adhered to the lower end surface of the cover plate, and the flexible layer is made of nitrile rubber.

[0037] Furthermore, in step S3, the second thin-film force sensor is mounted on the lower end surface of the flexible layer.

[0038] Furthermore, in step S4, when the amount of chatter or deformation exceeds the threshold, the online control module sends a command to the adaptive compensation unit to increase the support for the workpiece; when the amount of chatter and deformation is below the threshold, the online control module sends a command to the adaptive compensation unit to control the adaptive compensation unit to stop the displacement output.

[0039] Compared with existing technical solutions, the present invention has the following technical effects and advancements:

[0040] 1. This invention can effectively achieve stable clamping in the milling of complex frame-type thin-walled parts through workpiece contour positioning and fixing components; the flexible layer and the second thin-film force sensor attached under the cover plate can effectively achieve precise positioning and protection of the skin in welding processing, ensuring that the skin and the workpiece are completely in contact; through the compensation mechanism, it can effectively achieve adaptive support for easily deformable rib structures during processing, reducing processing chatter and deformation.

[0041] 2. This invention uses an adaptive machining method to detect chatter, monitor deformation, and provide compensatory support for workpieces. It has a simple structure and is easy to operate. It can effectively solve problems such as chatter and deformation in the cutting process of complex frame-type thin-walled parts, and difficulty in positioning the skin and low welding quality in the welding process, thus effectively improving the processing quality and efficiency. Attached Figure Description

[0042] Figure 1 The diagram shown is a structural schematic of the adaptive mounting unit in this invention.

[0043] Figure 2 The diagram shows the structure of the present invention used for workpiece milling.

[0044] Figure 3 The diagram shows the structure of the present invention used for workpiece welding.

[0045] Figure 4 The diagram shown is an enlarged view of the structure at point A when the present invention is used for workpiece welding.

[0046] Figure 5 The diagram shows a schematic of the adaptive compensation unit used in a workpiece according to the present invention.

[0047] Figure 6 The flowchart shown is an adaptive processing method for a complex frame-type thin-walled component provided by the present invention.

[0048] Wherein: 1-tooling;

[0049] 11-Adaptive mounting unit; 111-Base; 1111-First air inlet; 1112-First air outlet; 112-Workpiece contour positioning; 1121-Mounting boss; 11211-Tool groove; 1122-Positioning boss; 113-Fixed component; 1131-External fixed component; 1132-Internal fixed component; 11321-Pneumatic expansion clamp; 11322-Pneumatic gripper;

[0050] 12-Adaptive compensation unit; 121-Drive mechanism; 1211-Housing; 1212-Piezoelectric ceramic stack; 1213-Contact head; 1214-Link assembly; 12141-First link; 12142-Second link; 12143-Connecting push rod; 122-Compensation mechanism; 1221-Guide block; 1222-Push rod; 1223-Slider; 1224-Contact block; 1225-Adjusting bolt; 1226-First thin-film force sensor; 1227-Piezoelectric ceramic sheet;

[0051] 2-Workpiece;

[0052] 3-Skin;

[0053] 4-Cover plate; 41-Flexible layer; 42-Gun slot. Detailed Implementation

[0054] Please see Figures 1 to 6 The following specific examples illustrate embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be understood that many specific details are set forth in the following description to provide a thorough understanding of the present invention; however, the present invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Directional terms mentioned in the following embodiments, such as up, down, left, right, front, back, bottom, and top, are only for reference to the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the present invention.

[0055] Please combine Figure 1 and Figure 2 This application provides an adaptive machining fixture 1 for complex frame-type thin-walled parts, used for milling and welding of workpiece 2. The fixture 1 includes an adaptive mounting unit 11 and an adaptive compensation unit 12. The adaptive compensation unit 12 is mounted on the adaptive mounting unit 11. The adaptive mounting unit 11 is used for positioning and mounting the workpiece 2. The adaptive compensation unit 12 monitors and collects the chatter and deformation signals of the workpiece 2 in real time during the milling and welding process, and increases the support amount in real time to improve the support stiffness and reduce the machining chatter and deformation of the workpiece 2.

[0056] The adaptive mounting unit 11 includes a base 111, a workpiece contouring position 112, and fixing members 113. The workpiece contouring position 112 is used to place the workpiece 2, and at least two workpiece contouring positions 112 are arranged in a mirror image symmetrically on the upper surface of the base 111 to facilitate the processing of both sides of the workpiece 2; multiple fixing members 113 are installed on the upper surface of the base 111 near the workpiece contouring position 112, and when the workpiece 2 is installed in the workpiece contouring position 112, the workpiece 2 is clamped and fixed by the fixing members 113.

[0057] The base 111 has multiple first air inlets 1111 and multiple first air outlets 1112 on its side surface, and the first air inlets 1111 and the first air outlets 1112 are connected to an external air supply device. The upper surface of the base 111 also has multiple second air inlets 1113 and multiple second air outlets 1114. The fixing member 113 is installed at the corresponding positions of the second air inlets 1113 and the second air outlets 1114 and is connected to the second air inlets 1113 and the second air outlets 1114. The first air inlets 1111 and the second air inlets 1113 are connected, and the first air outlets 1112 and the second air outlets 1114 are connected. The pneumatic control of the fixing member 113 is achieved through the first air inlets 1111, the first air outlets 1112, the second air inlets 1113 and the second air outlets 1114. This embodiment improves the traditional tubular connection to a plate connection, which eliminates the need for additional pipes to achieve air supply control of pneumatic components, simplifying the structure and making operation easier.

[0058] Specifically, the workpiece contouring fixture 112 includes a mounting boss 1121 and a positioning boss 1122. The shape and size of the mounting boss 1121 are the same as those of the workpiece 2. When the workpiece 2 is placed in the mounting boss 1121, the workpiece 2 fits snugly against the mounting boss 1121, and the workpiece 2 will not move left or right or back and forth. Furthermore, the height of the mounting boss 1121 is greater than the thickness of the workpiece 2. The inner corners of the mounting boss 1121 are provided with tool grooves 11211 to avoid interference between the cutting tool and the fixture 2 during milling.

[0059] The positioning boss 1122 is disposed within the mounting boss 1121, and the positioning boss 1122 is approximately fitted to the position of the special shape of the workpiece 2, so as to achieve precise positioning of the workpiece 2.

[0060] In this embodiment, the workpiece 2 is a roughly trapezoidal frame thin-walled part, so the mounting boss 1121 also has a roughly trapezoidal structure. Furthermore, in this embodiment, the workpiece 2 has multiple arc-shaped surfaces within its frame, so the surface of the positioning boss 1122 that contacts the workpiece 2 is an arc surface, and it fits against the arc-shaped surface of the workpiece 2 to achieve positioning. In addition, in this embodiment, the angle of the mounting surface of the mounting boss 1121 is twice the wedge angle of the workpiece 2, so that the surface of the workpiece 2 to be processed is parallel to the base 111.

[0061] like Figure 2As shown, the fixing member 113 includes an external fixing member 1131 and an internal fixing member 1132. A plurality of external fixing members 1131 are arranged around the mounting boss 1121 and act on the upper surface of the workpiece 2. The internal fixing member 1132 is installed inside the mounting boss 1121 and acts on the side wall of the workpiece 2. Under the combined action of the external fixing member 1131 and the internal fixing member 1132, the workpiece 2 is positioned in an easy-to-process position and fixedly clamped.

[0062] In this embodiment, the external fixing component 1131 can be a corner clamping cylinder, which drives the pressure head to press down until it abuts against the upper surface of the workpiece 2, thereby fixing the workpiece 2 from above. The internal fixing component 1132 can be a pneumatic expansion clamp 11321 and a pneumatic gripper 11322. The pneumatic expansion clamp 11321 is installed on the mounting seat in the mounting boss 1121 and can act on the inner wall of the frame of the workpiece 2. The pneumatic gripper 11322 is installed in the mounting groove in the mounting boss 1121 and can act on the rib structure inside the workpiece 2. Of course, the types of the external fixing component 1131 and the internal fixing component 1132 provided in this embodiment are only preferred embodiments. In other embodiments, the external fixing component 1131 and the internal fixing component 1132 can also be other types of components.

[0063] like Figure 5 As shown, the adaptive compensation unit 12 includes a drive mechanism 121, a compensation mechanism 122, and a displacement output mechanism. The drive mechanism 121 is installed in a mounting groove located inside the mounting boss 1121 on the upper surface of the base 111. The compensation mechanism 122 is connected to the drive mechanism 121 through the displacement output mechanism and is located on the upper surface of the base 111. The drive mechanism 121 drives the compensation mechanism 122 to compensate for the chatter and deformation generated by the workpiece 2 during milling and welding.

[0064] Specifically, the drive mechanism 121 includes a housing 1211, a piezoelectric ceramic stack 1212, a contact head 1213, and a connecting rod assembly 1214. The housing 1211 is installed in a mounting groove located in the mounting boss 1121 on the upper surface of the base 111. The piezoelectric ceramic stack 1212, the contact head 1213, and the connecting rod assembly 1214 are installed inside the housing 1211. The piezoelectric ceramic stack 1212 generates displacement by applying a voltage to it, and the displacement is controlled by adjusting the voltage. The output end of the piezoelectric ceramic stack 1212 is connected to the connecting rod assembly 1214 through the contact head 1213, and the displacement is amplified and output to the compensation mechanism 122 through the connecting rod assembly 1214.

[0065] The linkage assembly 1214 includes two first linkages 12141 and two second linkages 12142. The input end of the first linkage 12141 is in line contact with the contact head 1213. The output end of the first linkage 12141 is connected to the input end of the second linkage 12142 through a connecting push rod 12143. The displacement generated by the piezoelectric ceramic stack 1212 is sequentially transmitted to the displacement output mechanism via the contact head 1213, the first linkage 12141, the connecting push rod 12143, and the second linkage 12142.

[0066] In this embodiment, the piezoelectric ceramic stack 1212 can achieve high resolution, high response speed and large load displacement output of 100μm. The connecting rod assembly 1214 can amplify and transmit the displacement output by the piezoelectric ceramic stack 1212 by 20 times with high precision, thereby achieving a displacement output of 0~20mm.

[0067] The compensation mechanism 122 includes a guide block 1221, push rods 1222, sliders 1223, and contact blocks 1224. The lower center of the guide block 1221 is threadedly connected to the drive mechanism 121 via an adjusting bolt 1225. The guide block 1221 is trapezoidal. Two sliders 1223 are respectively installed on the two sides of the guide block 1221. Two push rods 1222 are respectively installed in the two sliders 1223, and two contact blocks 1224 are respectively installed on the outer ends of the two push rods 1222. Under the drive of the drive mechanism 121, the guide block 1221 generates longitudinal displacement, driving the sliders 1223 to generate axial displacement, causing the contact blocks 1224 to also generate axial displacement, thereby changing the amount of support provided by the contact blocks 1224 to the workpiece 2.

[0068] In this embodiment, the end face of the contact block 1224 can be a nitrile rubber layer for angle compensation of the contact end face, which is suitable for support of various shapes and positions. At the same time, it can buffer and absorb the vibration generated by the workpiece 2 during the cutting process, achieving the effect of energy dissipation and vibration reduction. In addition, a first thin-film force sensor 1226 and a piezoelectric ceramic sheet 1227 are also installed on the end face of the contact block 1224. The first thin-film force sensor 1226 can detect the contact pressure between the contact block 1224 and the workpiece 2 to confirm whether the adaptive compensation unit 12 has been supported in place. The piezoelectric ceramic sheet 1227 is used to monitor and collect the chatter and deformation signals of the workpiece 2 structure in real time during the processing and feed them back to the PLC module. The PLC module transmits pulses to the adaptive compensation unit 12 for displacement output, thereby improving the support stiffness of the workpiece 2 and reducing processing chatter and deformation.

[0069] Please combine Figures 1 to 6This application also provides an adaptive machining method for complex frame-type thin-walled parts. When milling and welding the workpiece 2 using the tooling 1, the method includes the following steps:

[0070] S1: Install and secure workpiece 2;

[0071] S11: Install the workpiece 2, place the workpiece 2 in the mounting boss 1121, accurately position the workpiece 2 by positioning the boss 1122, and ensure that the surface of the workpiece 2 to be processed remains horizontal;

[0072] S12: Coarsely adjust the adaptive compensation unit 12, loosen the adjusting bolt 1225 in the adaptive compensation unit 12, control the push rod 1222 and the contact block 1224 to extend and displace to both ends, coarsely adjust the support distance of the adaptive compensation unit 12, and lock the adjusting bolt 1225 after adjustment.

[0073] S13: Fix the workpiece 2 by controlling the external fixing component 1131 and the internal fixing component 1132 through the control module to fix the upper end face, inner wall and rib structure of the workpiece 2 respectively;

[0074] S14: Control the adaptive compensation unit 12 to provide precise support and drive the adaptive compensation unit 12 to continue to move. When the first thin-film force sensor 1226 located on the end face of the contact block 1224 detects a pressure signal, it indicates that the adaptive compensation unit 12 is in place, and the installation and fixation of the workpiece 2 is completed.

[0075] S2: Mill the front side of the workpiece 2.

[0076] S3: Weld the front side of the workpiece 2;

[0077] S31: Install the welding parts, reverse control the external fixing part 1131 to detach from the upper end face of the workpiece, and place the skin 3 and cover plate 4 to be welded on the upper end of the workpiece 2.

[0078] Preferably, the shape of the cover plate 4 is completely consistent with the shape of the workpiece 2, and is used to fix the skin 3 during welding. A flexible layer 41 is attached to the lower end surface of the cover plate 4. The flexible layer 41 can be made of nitrile rubber, which is used to ensure that the skin 3 is completely attached to the workpiece 2, while protecting the surface quality of the skin 3. A second thin-film force sensor is also installed at the lower end of the flexible layer 41. The second thin-film force sensor can detect the pressure between the cover plate 4 and the skin 3, and confirm whether the skin 3 is pressed tightly and whether the skin 3 is completely attached to the workpiece 2.

[0079] S32: Fix the welded parts, control the external fixing parts 1131 to press the upper end face of the cover plate 4 until the second thin film force sensor detects the pressure signal, indicating that the cover plate 4 has been pressed and the skin 3 and the workpiece 2 have been completely attached;

[0080] S33: Spot welding process, the skin is spot welded through the gun groove 42 on the cover plate 4;

[0081] Preferably, the cover plate 4 adopts a steel-copper composite structure, that is, the cover plate 4 is made of steel as a whole, the area near the gun groove 42 is made of brass, and heat dissipation grooves are arranged near the gun groove 42 to effectively dissipate heat.

[0082] S34: Full welding process, control the external fixing part 1131 to detach from the upper end face of the cover plate 4, disassemble the cover plate 4, and perform full welding process on the skin 3.

[0083] S4: Online monitoring of flutter and deformation, adaptive compensation for flutter and deformation;

[0084] The piezoelectric ceramic sheet 1227 monitors and collects the chatter and deformation signals of the workpiece 2, and controls the adaptive compensation unit 12 to output displacement, adjusting the amount of support provided by the adaptive compensation unit to the workpiece online. Specifically, when the chatter or deformation exceeds a threshold, the PLC module transmits pulses to the adaptive compensation unit 12 to increase the amount of support provided to the workpiece 2, improve the support stiffness, and reduce processing chatter and deformation. When the chatter and deformation are below the threshold, the PLC transmits pulses to the adaptive compensation unit 12 to control the adaptive compensation unit 12 to stop the displacement output, completing the compensation support.

[0085] Step S4 is performed simultaneously with step S2.

[0086] S5: Milling and welding the reverse side of workpiece 2;

[0087] Control the external fixing member 1131 and the internal fixing member 1132 to loosen the workpiece 2, flip the workpiece 2 over and place it in the mirror-image mounting boss 1121, and then repeat the above steps S1 to S4. Complete the processing and disassemble the workpiece 2.

Claims

1. An adaptive machining fixture for complex frame-type thin-walled parts, characterized in that, include The workpiece is positioned in a contour-guided manner, with at least two of the workpiece contour-guided positions mirrored on the base. A fastener is installed on the base to fix the workpiece to be processed within the workpiece contour position; A drive mechanism is installed in a groove in the workpiece contouring position; the drive mechanism includes a piezoelectric ceramic stack, a contact head, and a connecting rod assembly, the connecting rod assembly being connected to the piezoelectric ceramic stack via the contact head, and the contact head being installed at the displacement output end of the piezoelectric ceramic stack; A compensation mechanism that contacts the internal rib structure of the workpiece; The driving mechanism drives the compensation mechanism to move; The compensation mechanism includes a contact block and a push rod. The contact block is installed at the end of the push rod, and the push rod drives the contact block to move. The contact block contacts the internal rib structure of the workpiece. The end face of the contact block that contacts the workpiece is a nitrile rubber layer. A first thin-film force sensor and a piezoelectric ceramic sheet are installed on the end face of the contact block that contacts the workpiece, respectively for detecting the pressure and chatter deformation of the workpiece.

2. The adaptive machining fixture for complex frame-type thin-walled parts according to claim 1, characterized in that, The base has a first air inlet and a first air outlet on its side, and a second air inlet and a second air outlet on its upper surface. The first air inlet and the second air inlet are connected to each other, and the first air outlet and the second air outlet are connected to each other. The fixing member is connected to the second air inlet and the second air outlet.

3. The adaptive machining fixture for complex frame-type thin-walled parts according to claim 2, characterized in that, The fastener includes an external fastener and an internal fastener. The external fastener is arranged around the outer periphery of the workpiece contouring position and is used to fix the upper end face of the workpiece. The internal fastener is installed inside the workpiece contouring position and is used to fix and support the internal structure of the workpiece.

4. The adaptive machining fixture for complex frame-type thin-walled parts according to claim 3, characterized in that, The external fixing component is a corner clamping cylinder, and the internal fixing component is a pneumatic expansion clamp and a pneumatic gripper. The pneumatic expansion clamp acts on the inner wall of the workpiece, and the pneumatic gripper acts on the internal rib structure of the workpiece.

5. The adaptive machining fixture for complex frame-type thin-walled parts according to claim 1, characterized in that, The workpiece contouring position includes a mounting boss and a positioning boss. The positioning boss is disposed within the mounting boss, and the workpiece is placed within the mounting boss. The positioning boss is aligned with the position of the workpiece's internal special shape.

6. A method for adaptively machining a complex frame-type thin-walled part using an adaptive machining fixture as described in any one of claims 1-5, characterized in that, Includes the following steps: Step S1: Install and secure the workpiece; Step S11: Install the workpiece by placing it inside the mounting boss and precisely positioning it using the positioning boss. Step S12: Coarsely adjust the adaptive compensation unit by controlling the push rod and contact block to extend and displace towards both ends, and coarsely adjust the support distance of the adaptive compensation unit; Step S13: Fix the workpiece: The external fixing component and the internal fixing component are controlled by the control module to fix the upper end face, inner wall and rib structure of the workpiece respectively; Step S14: Control the adaptive compensation unit to provide precise support, drive the adaptive compensation unit to continue to move, and when the first thin-film force sensor on the end face of the contact block detects a pressure signal, it indicates that the adaptive compensation unit is in place; Step S2: Mill the front side of the workpiece; Step S3: Weld the front side of the workpiece; Step S31: Install the welding parts, reverse control the external fixing parts to detach from the upper end face of the workpiece, and place the skin and cover plate to be welded on the upper end of the workpiece. Step S32: Fix the welded component and control the external fixing component to press against the upper end face of the cover plate until the second thin-film force sensor installed at the lower end of the cover plate detects the pressure signal; Step S33: Spot welding process, spot welding process is performed on the skin through the gun groove on the cover plate; Step S34: Full welding process, control the external fastener to detach from the upper end face of the cover plate, disassemble the cover plate, and perform full welding process on the skin; Step S4: Monitor flutter and deformation online, and adaptively compensate for flutter and deformation; By monitoring and collecting the chatter and deformation signals of the workpiece using a piezoelectric ceramic sheet, the adaptive compensation unit is controlled to output displacement, and the amount of support provided by the adaptive compensation unit to the workpiece is adjusted online. Step S5: Mill and weld the reverse side of the workpiece, control the external fastener and the internal fastener to loosen the workpiece, flip the workpiece and place it in another mounting boss set in a mirror image, and then repeat the above steps S1 to S4. Step S4 is performed simultaneously with step S2.

7. The adaptive machining method for complex frame-type thin-walled parts according to claim 6, characterized in that, In step S3, a flexible layer made of nitrile rubber is adhered to the lower end surface of the cover plate; the second thin-film force sensor is installed on the lower end surface of the flexible layer; heat dissipation grooves are formed around the gun groove; the cover plate is made of steel, and brass is embedded around the gun groove.

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