Flexible device and method for hot hole flanging forming of oversized metal box bottom

Abstract

The invention provides a flexible device and method for hot hole flanging forming of an oversized metal box bottom. The flexible device comprises a fixing device unit, a coordinate capturing system and a flexible forming unit. The fixing device unit is used for fixing the box bottom; the coordinate capturing system is used for obtaining contour coordinates of a to-be-flanged hole forming area and sending the contour coordinates to the flexible forming unit. After the flexible forming unit uses the contour coordinates as signals to control a multi-axis mechanical arm to move so as to position a mold, the mold is heated, so that a to-be-flanged hole forming area of the whole bottom is heated, and the current temperature is monitored; and when the temperature reaches a preset value, the multi-axis mechanical arm is controlled to move to a preset position to achieve part local forming. According to the method, high-reliability and large-deformation local precise forming of different positions of the ultra-large-size box bottom can be achieved, the part manufacturing process is simplified, the part forming precision is improved, and the production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of aerospace technology, and in particular to local precise heating and forming of large metal curved surface components, and in particular to a flexible device and method for hot punching of super-large-sized metal box bottoms. Background Art

[0002] The tank is the main structure of the rocket, usually composed of a barrel section, a short shell and a tank bottom. For the tank bottom components of aerospace launch vehicles, the diameter is generally more than 3 meters, the surface is complex, and it is a typical large thin-walled curved surface component. The traditional manufacturing method is to use a large number of welded structures, and weld reinforcement and welding deformation will affect the forming efficiency of the tank bottom structure, which cannot meet the needs of high reliability, low cost and high efficiency manufacturing in the aerospace field. Integration, large-scale, lightweight, high reliability and low cost are the development direction of advanced forming technology for the new generation of launch vehicles in the aerospace field. Taking the whole bottom structure composed of seven welded structures as an example, the tank bottom manufactured by the integral forming method eliminates all welds, the pressure bearing capacity is more than doubled, and the manufacturing cycle is shortened by nearly 2 / 3, which greatly improves the reliability and efficiency of rocket manufacturing.

[0003] However, the current large-scale thin-walled bottom components that are integrally formed mainly face the following forming difficulties when forming local flange-type strengthening features: 1) The bottom of the box is a typical weak rigidity complex thin-walled curved surface shell. It is difficult to identify the reference of the free state of the bottom of the box, which makes it difficult to accurately locate the local forming area; 2) The plastic deformation of local hole punching reaches about 30%, and the deformation is higher when forming smaller or deeper local geometric features. The bottom material of the box is aluminum alloy in the aging-strengthened state, which has poor plasticity and is prone to cracking defects during forming; 3) The hot forming method can improve the plasticity of aluminum alloy, but the temperature gradient of the non-heating position in the heating area needs to be controlled not to exceed 200°C, otherwise it will easily lead to a decrease in the strength of the aluminum alloy in the aging-strengthening state. For good thermal conductor materials such as aluminum alloy, it is difficult to control a large temperature gradient (200°C) within a short distance (50mm); In addition, when the external temperature exceeds the material aging temperature, the performance of aluminum alloy will deteriorate seriously with the increase of time. Therefore, when it is required to heat super-large parts locally, it becomes more difficult to achieve fast and stable heating efficiency with a large temperature gradient over a short distance.

[0004] Therefore, it is difficult to ensure the mechanical properties and accurately form oversized parts within a local range of 0.1 meters. It is very easy to have cracking defects or excessive shape and position accuracy, resulting in the scrapping of the entire product, which limits the application of integrated integral forming models for oversized components. Summary of the invention

[0005] In view of the defects in the prior art, the object of the present invention is to provide a flexible device and method for hot punching of super-large-sized metal box bottoms.

[0006] According to the present invention, a flexible device for hot punching of super-large-size metal box bottoms includes: a fixture unit, a coordinate capture system and a flexible forming unit; The fixing device unit is used to fix the bottom of the box; The coordinate capture system is used to obtain the contour coordinates of the area to be punched and formed and send them to the flexible forming unit; The flexible forming unit uses the contour coordinates as a signal to control the movement of the multi-axis robot to position the mold, heats the mold and then heats the entire bottom area to be punched and formed and monitors the current temperature. When the temperature reaches a preset value, the multi-axis robot is controlled to move to a predetermined position to achieve local forming of the part.

[0007] Preferably, the box bottom comprises aluminum alloy, aluminum-lithium alloy, magnesium alloy, copper and copper alloy in a heat-treated state; The part includes a metal curved surface component.

[0008] Preferably, the metal curved surface component includes a revolution thin-walled metal shell, a single-curvature thin-walled curved surface thin-walled cylindrical shell, and a double-curvature thin-walled curved surface component.

[0009] Preferably, the fixture unit comprises a fixture, a slider and a servo drive system, and can adjust the size to fix box bottoms of different diameters; a mark is engraved on the surface of the fixture, and the fixture is evenly divided into 4 areas, which are used to locate the quadrant where the box bottom area to be punched and formed is located, and the box bottom is fixed in the area; the slider is installed on the fixture, and the movement of the slider is controlled by the servo drive system to realize the rotation of the box bottom in the horizontal direction, and move the box bottom to the quadrant of the area to be punched and formed; The coordinate capture system is used to obtain the coordinates of the feature points in the quadrant to be formed and the contour coordinates of the area to be punched and formed, and feed them back to the control system in the flexible forming unit.

[0010] Preferably, the flexible forming unit comprises a control system, a multi-axis robotic arm, a convex and concave mold, a heating device and a temperature measurement system; The control system uses the feature points in the quadrant to be formed and the contour coordinates of the area to be punched, the hot punching forming size and the temperature of the area to be punched as target signals, and the displacement of the convex and concave molds as output control quantities, and realizes the movement and positioning of the forming mold by controlling the multi-axis mechanical arm to complete the precise forming of the box bottom; The multi-axis mechanical arm is used to install the convex and concave molds and realize the movement of the convex and concave molds; The convex and concave mold is used for forming the holes on the bottom of the box; The heating device is used to preheat and heat the convex and concave molds and the area to be punched and formed; The temperature measuring system is used to monitor the temperature of the convex and concave molds and the area to be punched and formed in real time, and feed back to the control system of the flexible forming unit.

[0011] According to a method for hot-drilling of a super-large-sized metal box bottom provided by the present invention, the hot-drilling method adopts the flexible device for hot-drilling of a super-large-sized metal box bottom, and comprises: Step S1: According to the quadrant of the box bottom area to be punched and formed and the surface mark of the fixing device, the slider is controlled by the servo drive system to realize the horizontal rotation of the box bottom, and the box bottom is moved and fixed to the quadrant of the box bottom area to be punched and formed; Step S2: constructing a three-dimensional model of the box bottom to be partially formed, obtaining the contour coordinates of the area to be punched and formed, and feeding back the coordinates to the control system of the flexible forming unit; Step S3: using the contour coordinates as a signal, the control system of the flexible forming unit controls the multi-axis robot arm to move the convex and concave molds until the convex and concave molds move to the area to be punched and formed at the bottom of the box and are in tangential contact with the area, and the position is set as the zero position of the convex and concave molds; Step S4: Keep the box bottom and the mold in the same position after positioning, start the heating device to heat the convex and concave molds respectively, and apply a certain pressure during the preheating process to make the box bottom and the forming mold fit tightly, and the applied pressure remains unchanged during the preheating process; Step S5: respectively monitoring the temperature of the convex and concave molds and the area to be punched and formed at the bottom of the box by a temperature measurement system, and feeding back the temperature data to the control system of the flexible forming unit in real time; Step S6: After the temperature of the convex and concave molds and the area on the bottom of the box to be punched and formed reaches a certain value, the control system sends a command to the multi-axis robotic arm to control the punch to move a certain distance to a determined position to realize local forming of the part. After forming, the mold returns to zero position.

[0012] Preferably, step S1 includes adjusting the fixing device according to the size of the box bottom to be partially formed, placing the box bottom horizontally on the fixing device, aligning it with the reference mark and firmly clamping it to fix the box bottom.

[0013] Preferably, step S2 includes dividing the three-dimensional model into four quadrants, namely quadrant I, quadrant II, quadrant III, and quadrant IV, selecting a typical point in the quadrant of the area to be punched as a feature point, defining the feature point as the absolute coordinate in the current quadrant, and obtaining the relative coordinate values ​​of each point on the area to be punched based on the feature point, finally obtaining the contour coordinates of the area to be punched, and feeding them back to the control system of the flexible forming unit.

[0014] Preferably, the heating device uses an electromagnetic heating coil to heat the convex and concave molds; Thermocouples were used to test the temperatures of the convex and concave molds and the area to be punched.

[0015] Preferably, when the quadrant of the area to be punched and formed on the bottom of the box changes, the size and type of the hot punching changes, or there are multiple local areas that need to be punched and formed, without shifting or flipping the bottom of the box, the bottom of the box is horizontally rotated and adjusted to the quadrant of the area to be punched and formed through the slider in the fixing device, the specifications and positions of the convex and concave molds are replaced, and the process of steps S2 to S6 is performed in sequence, thereby realizing the heating deformation of punching holes of different areas and different sizes of the entire bottom.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses the coordinates of the feature points in the quadrant to be formed and the contour coordinates of the area to be punched, the hot punching forming size and the temperature of the area to be punched as target signals, and the displacement of the convex and concave molds as the output control quantity, controls the multi-axis mechanical arm to realize the positioning and posture adjustment of the convex and concave molds in three-dimensional space, accurately controls the displacement of the convex and concave molds, realizes high-reliability hot forming at multiple local positions of the bottom of boxes of different size grades and different configurations, effectively improves the forming limit of the material, optimizes the forming process of the bottom parts, greatly shortens the manufacturing cycle of the bottom, and improves the product quality consistency of the bottom parts. In addition, the present invention can control the movement of the slider through the servo drive system in the fixing device unit without shifting or flipping the bottom of the box, realize the rotation of the bottom of the box in the horizontal direction, and move the bottom of the box to the quadrant of the area to be punched. At the same time, by changing the specifications and positions of the convex and concave molds, the heating deformation of punching holes of different areas and different sizes of the whole bottom can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 It is a schematic diagram of the flexible device for hot-tipped hole forming of the bottom of a metal box according to the present invention.

[0018] Figure 2 It is a schematic diagram of obtaining the contour coordinates of the area to be punched and formed in the present invention.

[0019] Figure 3 It is a schematic diagram of the change of the position of the convex and concave molds on the bottom of the metal box of the present invention.

[0020] Figure 4 It is a schematic diagram of the change of the position of the metal box bottom of the present invention. DETAILED DESCRIPTION

[0021] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0022] The present invention can achieve precise control of the temperature field of large-size parts, improve heating efficiency, increase forming limit and forming quality, reduce production scrap rate, and ensure the service performance and application of integral parts of aerospace light alloy materials.

[0023] According to the present invention, a flexible device for hot punching of super-large-sized metal box bottom is provided. Figure 1 As shown, it includes: a fixing device unit, a coordinate capture system and a flexible forming unit. The fixing device unit is used to fix the bottom of the box. The coordinate capture system is used to obtain the contour coordinates of the area to be punched and sent to the flexible forming unit. After the flexible forming unit uses the contour coordinates as a signal to control the movement of the multi-axis robot arm to position the mold, it heats the mold and then heats the entire bottom area to be punched and monitors the current temperature. When the temperature reaches a preset value, the multi-axis robot arm is controlled to move to a predetermined position to achieve local forming of the part. Among them, the bottom of the box includes aluminum alloy, aluminum-lithium alloy, magnesium alloy, copper and copper alloy in a heat-treated state. The part includes a metal curved surface component, and the metal curved surface component includes a rotating thin-walled metal shell, a single-curvature thin-walled curved surface thin-walled cylindrical shell, and a double-curvature thin-walled curved surface component.

[0024] The fixture unit includes a fixture, a slider and a servo drive system, and the size can be adjusted to fix box bottoms of different diameters; a mark is engraved on the surface of the fixture, and the fixture is evenly divided into 4 areas, which are used to locate the quadrant of the box bottom area to be punched and formed, and fix the box bottom in this area; the slider is installed on the fixture, and the movement of the slider is controlled by the servo drive system to realize the rotation of the box bottom in the horizontal direction, and move the box bottom to the quadrant of the area to be punched and formed; The coordinate capture system is used to obtain the coordinates of the feature points in the quadrant to be formed and the contour coordinates of the area to be punched and formed, and feed them back to the control system in the flexible forming unit.

[0025] The flexible forming unit includes a control system, a multi-axis robotic arm, a convex-concave mold, a heating device and a temperature measurement system. The control system uses the feature points in the quadrant to be formed and the contour coordinates of the area to be punched, the hot punching forming size and the temperature of the area to be punched as target signals, and the displacement of the convex-concave mold as the output control quantity. By controlling the multi-axis robotic arm, the movement and positioning of the forming mold are realized to complete the precise forming of the bottom of the box. The multi-axis robotic arm is used to install the convex-concave mold and realize the movement of the convex-concave mold. The convex-concave mold is used for punching the bottom of the box. The heating device is used to realize the preheating and heating of the convex-concave mold and the area to be punched. The temperature measurement system is used to monitor the temperature of the convex-concave mold and the area to be punched in real time, and feed it back to the control system of the flexible forming unit.

[0026] According to a method for hot-drilling of a super-large-sized metal box bottom provided by the present invention, the hot-drilling method adopts the flexible device for hot-drilling of a super-large-sized metal box bottom, and comprises: Step S1: Fix the bottom of the box horizontally on the fixing device. Adjust the fixing device to adapt to the size of the box bottom according to the size of the box bottom to be partially formed; according to the quadrant of the box bottom to be punched and the surface mark of the fixing device, control the movement of the slider through the servo drive system to realize the horizontal rotation of the box bottom, move the box bottom to the quadrant of the box bottom to be punched and formed, align it with the reference mark, and then firmly clamp it to fix the box bottom.

[0027] Step S2: Construct a three-dimensional model of the bottom of the box to be partially formed, obtain the contour coordinates of the area to be punched, and feed it back to the control system of the flexible forming unit. The three-dimensional model is divided into four quadrants, namely, the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant. A typical point in the quadrant of the area to be punched is selected as a feature point, which is defined as the absolute coordinate in the quadrant. Based on the feature point, the relative coordinate values ​​of each point on the area to be punched are obtained, and finally the contour coordinates of the area to be punched are obtained, and fed back to the control system of the flexible forming unit. Specifically, taking the area to be punched in the second quadrant of the first quadrant as an example, a point in the second quadrant of the first quadrant is selected as a feature point, and the feature point is set as an absolute coordinate. Based on the coordinate capture system, the relative coordinate values ​​of each point on all the areas to be punched in the second quadrant of the first quadrant are obtained, and finally the contour coordinates of each area to be punched are obtained.

[0028] Step S3: Using the coordinates obtained by the coordinate capture system as a signal, the control system of the flexible forming unit controls the multi-axis robot arm to realize the movement of the male and female molds, until the male and female molds move to the area to be punched at the bottom of the box and are in tangential contact with the area, and the position is set as the zero position of the male and female molds. The multi-axis robot arm is controlled to move the male and female molds, firstly, the male and female molds are moved to the position of the feature points to realize the positioning verification of the initial position of the male and female molds; further, using the contour coordinates of the area to be punched obtained by the coordinate capture system as a signal, the multi-axis robot arm is controlled to move the male and female molds to the area to be punched and in tangential contact with it.

[0029] Step S4: Keep the box bottom and the mold in the same position after positioning, and apply a certain pressure during the preheating process to make the box bottom fit tightly with the forming mold. The applied pressure remains unchanged during the preheating process, and the entire bottom area to be punched is heated by heating the mold. Start the heating device to heat the convex and concave molds respectively, and apply a certain pressure during the preheating process to make the box bottom fit tightly with the forming mold. The applied pressure remains unchanged during the preheating process. The heating device uses an electromagnetic heating coil to heat the convex and concave molds to further achieve the purpose of heating the punching area.

[0030] Step S5: The temperature of the convex and concave mold and the area to be punched on the bottom of the box are monitored by the temperature measurement system, and the temperature data is fed back to the control system of the flexible forming unit in real time. The temperature of the convex and concave mold and the area to be punched are tested by thermocouples.

[0031] Step S6: After the temperature of the convex-concave mold and the area to be punched on the bottom of the box reaches a certain value, the control system issues a command to the multi-axis robot arm to control the punch to move a certain distance to a determined position to realize partial forming of the part, and the mold returns to zero position after forming. After the temperature of the convex-concave mold and the area to be punched on the bottom of the box reaches a certain value, the control system uses the coordinates of the feature points in the quadrant to be formed, the contour coordinates of the area to be punched, the forming size of the hole to be punched, and the temperature of the area to be punched as target signals, and the force displacement as the output control quantity, and issues a command to the multi-axis robot arm to control the punch to move a certain distance to a determined position to realize partial forming of the part, and the mold returns to zero position after forming. When the quadrant of the area to be punched and formed on the bottom of the box changes, the size and type of hot punching changes, or there are multiple local areas that need to be punched and formed, specifically, without shifting or flipping the bottom of the box, the servo drive system in the fixing device unit can be used to control the movement of the slider to realize horizontal rotation of the bottom of the box, adjust it to the quadrant of the area to be punched and formed, and realize hot punching in different quadrants of the bottom of the box; by changing the specifications of the convex and concave molds, hot punching of different sizes of the bottom of the box can be realized; by adjusting the position of the convex and concave molds, specifically, when the type of hole to be punched is an external punching hole, the convex mold is installed on the inside of the whole bottom, and the concave mold is installed on the outside of the whole bottom. When the punching type changes to an inward punching hole, there is no need to flip the whole bottom, only the concave mold of the corresponding specification needs to be installed on the inside of the bottom, and the convex mold of the corresponding specification needs to be installed on the outside of the whole bottom to realize the inward punching. Then, the process of steps S2 to S6 is performed in sequence, so as to realize the heating deformation of punching holes of different areas and different sizes of the whole bottom, that is, a set of devices realizes the local flexible heating forming of different positions of metal curved surface components of different size levels of the whole bottom.

[0032] The control system in the flexible forming unit uses the coordinates of the feature points in the quadrant to be formed, the contour coordinates of the area to be punched, the hot punching forming size and the temperature of the area to be punched as the target signal, and the displacement of the convex and concave molds as the output control quantity to control the multi-axis robotic arm to realize the positioning and posture adjustment of the convex and concave molds in three-dimensional space, accurately control the displacement of the convex and concave molds, and realize high-precision punching forming in various areas of the box bottom. Under the premise of keeping the box bottom in a horizontal state and not offsetting or flipping the box bottom, local heating and high-precision punching forming can be realized at any position on large-sized and multi-sized rotary shell metal components.

[0033] Furthermore, combined with Figure 1 To Attachment Figure 4 The flexible device and method for hot punching of super-large-sized metal box bottoms of the present invention are specifically described as follows: Figure 1It is a schematic diagram of a flexible device for hot punching of a metal box bottom. First, the control system of the flexible forming unit uses the coordinates obtained by the coordinate capture system as signals to control the movement of the multi-axis robotic arm, so that the convex and concave molds move to the area to be punched and make tangential contact with it; then, the electromagnetic heating ring in the heating device is started to heat the convex and concave molds to achieve the purpose of heating the area to be punched, and the temperature of the convex and concave molds and the area to be punched on the bottom of the box are monitored respectively through the temperature measuring system, and the temperature data is fed back to the control system of the flexible forming unit in real time; finally, after the temperature of the convex and concave molds and the area to be punched on the bottom of the box reaches a certain value, the control system uses the forming size of the hole to be punched and the temperature of the area to be punched as target signals, and the force displacement as the output control quantity, and issues instructions to the multi-axis robotic arm to control the punch to move a certain distance to a determined position to realize local forming of the part.

[0034] Figure 2 This is a schematic diagram for obtaining the contour coordinates of the area to be punched on the bottom of a metal box. As shown in the figure, according to the quadrant where the area to be punched is located, a typical point in the quadrant of the area to be punched is selected as a feature point, and it is defined as the absolute coordinate in the quadrant. According to the three-dimensional model of the bottom of the box, the relative coordinate values ​​of each point of the contour of the area to be punched are further captured, and finally the feature points in the quadrant to be formed and the contour coordinates of the area to be punched are obtained and fed back to the control system. Among them, the typical points include points on the radial and axial arc lengths of the central sphere of the quadrant where the area to be punched is located.

[0035] Figure 3 The schematic diagram of the change of the metal box bottom mold position is as follows: Figure 3 As shown in (a), due to the change in the position of the area to be punched, based on the contour coordinates of the area to be punched fed back by the coordinate capture system, it is necessary to control the movement of the convex and concave molds through a multi-axis robot. It should be noted that if the size of the hole to be punched changes, the mold specifications need to be changed during this process; Figure 3 As shown in (b), when the hole type to be punched is an outward-turned hole, the punch is installed on the inner side of the entire bottom and the die is installed on the outer side of the entire bottom. When the hole type is changed to an inward-turned hole, there is no need to flip the entire bottom. Only the die of the corresponding specification needs to be installed on the inner side of the bottom and the punch of the corresponding specification needs to be installed on the outer side of the entire bottom to realize the inward-turned hole forming.

[0036] Figure 4 The schematic diagram of the change of the metal box bottom position is as follows: Figure 4 As shown in (a), according to the markings on the surface of the fixing device, align the quadrant markings on the bottom of the box and fix the bottom of the box; Figure 4 (b) and Figure 4 As shown in (c), the slider is installed on the fixing device. When the area of ​​the box bottom to be punched and formed changes, the servo drive system in the fixing device unit controls the movement of the slider to realize the horizontal rotation of the box bottom and move the box bottom to the quadrant of the area to be punched and formed.

[0037] The present invention aims to solve the problems of difficulty in local hot forming of oversized integral thin-walled components, low forming accuracy, low forming stability, difficulty in temperature field control and easy occurrence of cracking defects.

[0038] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0039] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A flexible device for hot punching of metal box bottoms of super-large size, characterized in that: include: fixture units, coordinate capture systems, and flexible forming units; The fixture unit includes a fixture, a slider and a servo drive system, and can be adjusted in size to fix box bottoms of different diameters; The coordinate capture system is used to obtain the coordinates of the feature points in the quadrant to be formed and the contour coordinates of the area to be punched and formed, and feed them back to the control system in the flexible forming unit; The coordinate capture system divides the three-dimensional model of the box bottom to be punched into four quadrants, selects a typical point in the quadrant as a feature point, defines the feature point as the absolute coordinate in the current quadrant, obtains the relative coordinate value of each point on the area to be punched based on the feature point, and finally obtains the contour coordinates of the area to be punched; The typical points include points on the radial and axial arc lengths of the central sphere of the quadrant where the area to be punched holes is located on the bottom of the box; The flexible forming unit uses the contour coordinates as a signal to control the movement of the multi-axis robot to position the mold, and then heats the mold to heat the entire bottom area to be punched and formed and monitors the current temperature. When the temperature reaches a preset value, the multi-axis robot is controlled to move to a predetermined position to achieve local forming of the part.

2. The flexible device for hot punching of super-large-sized metal box bottom according to claim 1 is characterized in that: The box bottom includes aluminum alloy, aluminum-lithium alloy, magnesium alloy, copper and copper alloy in a heat-treated state; The part includes a metal curved surface component.

3. The flexible device for hot punching of super-large-sized metal box bottom according to claim 2 is characterized in that: The metal curved surface components include a rotational thin-walled metal shell, a single-curvature thin-walled curved surface thin-walled cylindrical shell, and a double-curvature thin-walled curved surface component.

4. The flexible device for hot punching of super-large-sized metal box bottom according to claim 1 is characterized in that: The fixing device unit can fix box bottoms of different diameters by adjusting the size, and is provided with a slider to control the rotation of the box bottom in the horizontal direction; The surface of the fixing device is engraved with a mark, which divides the fixing device into four areas for locating the quadrant of the box bottom area to be punched and formed, and fixing the box bottom in the area; the slider is installed on the fixing device, and the movement of the slider is controlled by the servo drive system to realize the horizontal rotation of the box bottom and move the box bottom to the quadrant of the box bottom area to be punched and formed.

5. The flexible device for hot punching of super-large-sized metal box bottom according to claim 1 is characterized in that: The flexible forming unit includes a control system, a multi-axis robotic arm, a convex and concave mold, a heating device and a temperature measurement system; The control system uses the feature points in the quadrant to be formed and the contour coordinates of the area to be punched, the hot punching forming size and the temperature of the area to be punched as target signals, and the displacement of the convex and concave molds as output control quantities, and realizes the movement and positioning of the forming mold by controlling the multi-axis mechanical arm to complete the precise forming of the box bottom; The multi-axis mechanical arm is used to install the convex and concave molds and realize the movement of the convex and concave molds; The convex and concave mold is used for forming the holes on the bottom of the box; The heating device is used to preheat and heat the convex and concave molds and the area to be punched and formed; The temperature measuring system is used to monitor the temperature of the convex and concave molds and the area to be punched and formed in real time, and feed back to the control system of the flexible forming unit.

6. A method for hot punching of metal box bottoms of super-large size, characterized in that: The flexible device for hot punching of super-large-sized metal box bottom according to any one of claims 1 to 5 is used, and the hot punching method comprises: Step S1: According to the quadrant of the box bottom area to be punched and formed and the surface mark of the fixing device, the slider is controlled by the servo drive system to realize the horizontal rotation of the box bottom, and the box bottom is moved and fixed to the quadrant of the box bottom area to be punched and formed; Step S2: constructing a three-dimensional model of the box bottom to be partially formed, obtaining the contour coordinates of the area to be punched and formed, and feeding back the coordinates to the control system of the flexible forming unit; Step S3: using the contour coordinates as a signal, the control system of the flexible forming unit controls the multi-axis robot arm to move the convex and concave molds until the convex and concave molds move to the area to be punched and formed at the bottom of the box and are in tangential contact with the area, and the position is set as the zero position of the convex and concave molds; Step S4: Keep the box bottom and the mold in the same position after positioning, start the heating device to heat the convex and concave molds respectively, and apply a certain pressure during the preheating process to make the box bottom and the forming mold fit tightly, and the applied pressure remains unchanged during the preheating process; Step S5: respectively monitoring the temperature of the convex and concave molds and the area to be punched and formed at the bottom of the box by a temperature measurement system, and feeding back the temperature data to the control system of the flexible forming unit in real time; Step S6: After the temperature of the convex and concave molds and the area on the bottom of the box to be punched and formed reaches a certain value, the control system sends a command to the multi-axis robotic arm to control the punch to move a certain distance to a determined position to realize local forming of the part. After forming, the mold returns to zero position.

7. The method for hot punching of super-large-size metal box bottom according to claim 6, characterized in that: Step S1 includes adjusting the fixing device according to the size of the box bottom to be partially formed, placing the box bottom horizontally on the fixing device, aligning it with the reference mark and firmly clamping it to fix the box bottom.

8. The method for hot punching of super-large-size metal box bottom according to claim 6, characterized in that: The step S2 includes dividing the three-dimensional model into four quadrants, namely quadrant I, quadrant II, quadrant III, and quadrant IV, selecting a typical point in the quadrant of the area to be punched as a feature point, defining the feature point as the absolute coordinate in the current quadrant, and obtaining the relative coordinate values ​​of each point on the area to be punched based on the feature point, and finally obtaining the contour coordinates of the area to be punched, and feeding them back to the control system of the flexible forming unit.

9. The method for hot punching of super-large-size metal box bottom according to claim 6, characterized in that: The heating device uses an electromagnetic heating coil to heat the convex and concave molds; Thermocouples were used to test the temperatures of the convex and concave molds and the area to be punched.

10. The method for hot punching of super-large-sized metal box bottom according to claim 6, characterized in that: When the quadrant of the area to be punched and formed on the bottom of the box changes, the size and type of hot punching changes, or there are multiple local areas that need to be punched and formed, the servo drive system in the fixing device unit controls the movement of the slider to realize horizontal rotation of the bottom of the box and adjust it to the quadrant of the area to be punched and formed, so as to realize hot punching and forming in different quadrants of the bottom of the box; By changing the specifications of the convex and concave molds, hot-drilling of different sizes of the box bottom can be achieved; By adjusting the positions of the male and female molds, when the hole type to be punched is an outward-turned hole, the male mold is installed on the inside of the entire bottom and the female mold is installed on the outside of the entire bottom; when the hole type is changed to an inward-turned hole, there is no need to flip the entire bottom, just install the female mold of the corresponding specification on the inside of the bottom and the male mold of the corresponding specification on the outside of the entire bottom to realize the inward-turned hole forming.

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