Flexible Device and Method for Hot Flanging Hole Forming of Ultra-Large-Size Metal Box Bottom

Abstract

The present invention provides a flexible device and method for hot hole-flanging forming of an ultra-large-sized metal box bottom, including: a fixing device unit, a coordinate capture system, and a flexible forming unit; the fixing device unit is used to fix the box bottom; the coordinate capture system is used to obtain the contour coordinates of the area to be hole-flanged and form and send them to the flexible forming unit; after the flexible forming unit controls the movement of a multi-axis robotic arm to position the mold based on the contour coordinates, the mold is heated, and then the entire bottom area to be hole-flanged is heated and the current temperature is monitored. When the temperature reaches a preset value, the multi-axis robotic arm is controlled to move to a predetermined position to achieve local forming of the part. The present invention can achieve local precise forming with high reliability and large deformation at different positions of an ultra-large-sized box bottom, simplify the part manufacturing process, improve the part forming accuracy, and reduce the production cost.

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:

[0004] 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;

[0005] 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;

[0006] 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);

[0007] 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.

[0008] 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

[0009] In view of the defects in the prior art, the purpose of the present invention is to provide a flexible device and method for hot flanging forming of the bottom of an extra-large-sized metal box.

[0010] A flexible device for hot flanging forming of the bottom of an extra-large-sized metal box according to the present invention includes: a fixing device unit, a coordinate capturing system, and a flexible forming unit;

[0011] The fixing device unit is used to fix the bottom of the box;

[0012] The coordinate capturing system is used to obtain the contour coordinates of the area to be flanged and formed and send them to the flexible forming unit;

[0013] After the flexible forming unit controls the movement of the multi-axis robotic arm to position the mold based on the contour coordinates, it heats the mold, thereby heating the entire bottom area to be flanged and formed and monitoring the current temperature. When the temperature reaches the preset value, it controls the multi-axis robotic arm to move to a predetermined position to achieve local forming of the part.

[0014] Preferably, the bottom of the box includes aluminum alloys, aluminum-lithium alloys, magnesium alloys, copper and copper alloys in a heat-treated state;

[0015] The part includes a metal curved surface member.

[0016] Preferably, the metal curved surface member includes a rotary thin-walled metal shell, a single-curvature thin-walled curved surface thin-walled cylindrical shell, and a double-curvature thin-walled curved surface member.

[0017] Preferably, the fixing device unit includes a fixing device, a slider, and a servo drive system, which can adjust the size to fix the bottom of the box with different diameters; markings are engraved on the surface of the fixing device, and the fixing device is evenly divided into 4 areas for positioning the quadrant where the area to be flanged and formed on the bottom of the box is located, and fixing the bottom of the box 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 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 flanged and formed;

[0018] The coordinate capturing system is used to obtain the coordinates of the feature points within the quadrant to be formed and the contour coordinates of the area to be flanged and formed, and feed them back to the control system in the flexible forming unit.

[0019] Preferably, the flexible forming unit includes a control system, a multi-axis robotic arm, a convex-concave mold, a heating device, and a temperature measuring system;

[0020] The control system uses the contour coordinates of the feature points within the quadrant to be formed, the contour coordinates of the area to be formed by hole flanging, the hot hole flanging forming size, and the temperature of the area to be formed by hole flanging as target signals, and uses the displacement of the convex-concave die as the output control quantity. By controlling the multi-axis robotic arm, the movement and positioning of the forming die are realized, and the precise forming of the bottom of the box is completed;

[0021] The multi-axis robotic arm is used to install the convex-concave die and realize the movement of the convex-concave die;

[0022] The convex-concave die is used for hole flanging forming of the bottom of the box;

[0023] The heating device is used to preheat and heat the convex-concave die and the area to be formed by hole flanging;

[0024] The temperature measurement system is used to monitor the temperature of the convex-concave die and the area to be formed by hole flanging in real time and feedback it to the control system of the flexible forming unit.

[0025] According to a method for hot hole flanging forming of an ultra-large-size metal box bottom provided by the present invention, using the flexible device for hot hole flanging forming of an ultra-large-size metal box bottom, the method for hot hole flanging forming includes:

[0026] Step S1: According to the quadrant where the area to be formed by hole flanging of the box bottom is located and the surface markings of the fixing device, control the slider through the servo drive system to realize the horizontal rotation of the box bottom, and move and fix the box bottom to the quadrant of the area to be formed by hole flanging;

[0027] Step S2: Construct a three-dimensional model of the box bottom to be locally formed, obtain the contour coordinates of the area to be formed by hole flanging, and feedback them to the control system of the flexible forming unit;

[0028] Step S3: Using the contour coordinates as signals, control the multi-axis robotic arm through the control system of the flexible forming unit to move the convex-concave die until the convex-concave die moves to the area to be formed by hole flanging of the box bottom and is in tangential contact with the area, and set this position as the zero position of the convex-concave die;

[0029] Step S4: Keep the positions of the box bottom and the die after positioning unchanged, start the heating device to heat the convex-concave die respectively, and apply a certain pressure during the preheating process to make the box bottom fit tightly with the forming die, and the pressure applied remains unchanged during the preheating process;

[0030] Step S5: Monitor the temperatures of the convex-concave die and the area to be formed by hole flanging of the box bottom respectively through the temperature measurement system, and feedback the temperature data to the control system of the flexible forming unit in real time;

[0031] Step S6: After the temperatures of the convex-concave die and the area to be formed by hole flanging of the box bottom reach a certain value, the control system issues an instruction to the multi-axis robotic arm, controls the punch to move a certain distance to a determined position, and then realizes the local forming of the part. After forming, the die returns to the zero position.

[0032] Preferably, step S1 includes adjusting the fixing device according to the size of the bottom of the box to be locally formed, placing the bottom of the box horizontally on the fixing device, firmly clamping it after aligning with the reference marking line, and fixing the bottom of the box.

[0033] Preferably, the step S2 includes dividing the three-dimensional model into 4 quadrants, namely the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant, selecting a typical point within the quadrant of the area to be formed by hole flipping as the feature point, defining the feature point as the absolute coordinates within the current quadrant, obtaining the relative coordinate values of each point on the area to be formed by hole flipping based on the feature point, finally obtaining the contour coordinates of the area to be formed by hole flipping, and feeding them back to the control system of the flexible forming unit.

[0034] Preferably, an electromagnetic heating coil is selected as the heating device to heat the convex and concave molds;

[0035] Thermocouples are used to measure the temperatures of the convex and concave molds and the area to be formed by hole flipping respectively.

[0036] Preferably, when the quadrant where the area to be formed by hole flipping on the bottom of the box changes, the size and type of the hot hole flipping forming change, or there are multiple local areas that need to be formed by hole flipping, without offsetting 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 formed by hole flipping through the slider in the fixing device, the specifications and positions of the convex and concave molds are changed, and the process from step S2 to step S6 is executed in sequence, so as to realize the heating deformation of hole flipping in different areas and different sizes of the whole bottom.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention uses the coordinates of the feature points within the quadrant to be formed, the contour coordinates of the area to be formed by hole flipping, the size of the hot hole flipping forming, and the temperature of the area to be formed by hole flipping as the target signals, and the displacement of the convex and concave molds as the output control quantity, controls the multi-axis robotic arm to realize the positioning and attitude adjustment of the convex and concave molds in three-dimensional space, accurately controls the displacement amount of the convex and concave molds, realizes the highly reliable hot forming of multiple local positions of the bottom of the box with different size levels and different configurations, effectively improves the forming limit of the material, optimizes the forming process of the bottom of the box parts, greatly shortens the manufacturing cycle of the bottom of the box, and improves the product quality consistency of the bottom of the box parts. In addition, the present invention can, without offsetting or flipping the bottom of the box, control the movement of the slider through the servo drive system in the fixing device unit to realize the rotation of the bottom of the box in the horizontal direction, and move and fix the bottom of the box to the quadrant of the area to be formed by hole flipping. At the same time, by changing the specifications and positions of the convex and concave molds, the heating deformation of hole flipping in different areas and different sizes of the whole bottom is realized. Description of the Drawings

[0039] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non - limiting embodiments read in conjunction with the accompanying drawings:

[0040] Figure 1 It is a schematic diagram of the flexible device for hot - hole - flanging forming of the metal box bottom of the present invention.

[0041] Figure 2 It is a schematic diagram for obtaining the contour coordinates of the area to be hole - flanging formed of the present invention.

[0042] Figure 3 It is a schematic diagram of the position change of the convex - concave mold of the metal box bottom of the present invention.

[0043] Figure 4 It is a schematic diagram of the position change of the metal box bottom of the present invention. Detailed Embodiments

[0044] The present invention will be 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 do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all fall within the protection scope of the present invention.

[0045] The present invention can achieve precise control of the temperature field of large - size parts, improve the heating efficiency, increase the forming limit and forming quality, reduce the production scrap rate, and ensure the service performance and application of integral parts made of aerospace light alloy materials.

[0046] A flexible device for hot - hole - flanging forming of an extra - large - size metal box bottom according to the present invention, as Figure 1 shown, includes: a fixing device unit, a coordinate capture system, and a flexible forming unit. The fixing device unit is used to fix the box bottom. The coordinate capture system is used to obtain the contour coordinates of the area to be hole - flanging formed and send them to the flexible forming unit. After the flexible forming unit controls the multi - axis robotic arm to move and position the mold based on the contour coordinates, it heats the mold and then heats the entire area to be hole - flanging formed of the bottom and monitors the current temperature. When the temperature reaches the preset value, it controls the multi - axis robotic arm to move to a predetermined position to achieve local forming of the part. Among them, the box bottom includes aluminum alloys, aluminum - lithium alloys, magnesium alloys, copper and copper alloys in a heat - treated state. The part includes a metal curved surface component, and the metal curved surface component includes a rotary thin - wall metal shell, a single - curvature thin - wall curved surface thin - wall column shell, and a double - curvature thin - wall curved surface component.

[0047] The fixing device unit includes a fixing device, a slider, and a servo drive system, and can adjust its size to fix the bottom of boxes with different diameters; markings are engraved on the surface of the fixing device, dividing the fixing device into 4 regions equally, which are used to locate the quadrant where the area to be formed by hole flipping on the bottom of the box is located, and fix the bottom of the box in this region; the slider is installed on the fixing device, and the movement of the slider is controlled by the servo drive system to 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 formed by hole flipping.

[0048] The coordinate capture system is used to obtain the coordinates of feature points within the quadrant to be formed and the contour coordinates of the area to be formed by hole flipping, and feed them back to the control system in the flexible forming unit.

[0049] 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 coordinates of feature points within the quadrant to be formed, the contour coordinates of the area to be formed by hole flipping, the size of hot hole flipping forming, and the temperature of the area to be formed by hole flipping as target signals, and uses the displacement of the convex-concave mold as the output control quantity, and controls the movement and positioning of the forming mold by controlling the multi-axis robotic arm 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 hole flipping forming of the bottom of the box. The heating device is used to preheat and heat the convex-concave mold and the area to be formed by hole flipping. The temperature measurement system is used to monitor the temperature of the convex-concave mold and the area to be formed by hole flipping in real time, and feed it back to the control system of the flexible forming unit.

[0050] According to a method for hot hole flipping forming of an ultra-large size metal box bottom provided by the present invention, using the flexible device for hot hole flipping forming of an ultra-large size metal box bottom, the method for hot hole flipping forming includes:

[0051] Step S1: Horizontally fix the bottom of the box on the fixing device. Adjust the fixing device according to the size of the bottom of the box to be locally formed to adapt to the size of the bottom of the box; according to the quadrant of the area to be formed by hole flipping on the bottom of the box and the markings on the surface of the fixing device, control the movement of the slider through the servo drive system to realize the rotation of the bottom of the box in the horizontal direction, move the bottom of the box to the quadrant of the area to be formed by hole flipping, align it with the reference marking line, and firmly clamp it to fix the bottom of the box.

[0052] Step S2: Construct a 3D model of the bottom of the box to be locally formed, obtain the contour coordinates of the area to be flanging formed, and feedback them to the control system of the flexible forming unit. Divide the 3D model into 4 quadrants, namely the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant. Select a typical point within the quadrant of the area to be flanging formed as the feature point, define its absolute coordinates within this quadrant, and obtain the relative coordinate values of each point on the area to be flanging formed based on this feature point. Finally, obtain the contour coordinates of the area to be flanging formed and feedback them to the control system of the flexible forming unit. Specifically, taking the area to be flanging formed in the first quadrant and biased towards the second quadrant as an example, select 1 point in the first quadrant and biased towards the second quadrant as the feature point, set the feature point as the absolute coordinates, and obtain the relative coordinate values of each point on all areas to be flanging formed in the first quadrant and biased towards the second quadrant based on the coordinate capture system. Finally, obtain the contour coordinates of each area to be flanging formed.

[0053] Step S3: Using the coordinates obtained by the coordinate capture system as signals, control the multi-axis robotic arm through the control system of the flexible forming unit to move the convex and concave molds until the convex and concave molds move to the area to be flanging formed on the bottom of the box and are in tangential contact with this area, and set this position as the zero position of the convex and concave molds. Control the multi-axis robotic arm to move the convex and concave molds. First, move the convex and concave molds to the position of the feature point to achieve the positioning verification of the initial position of the convex and concave molds. Further, using the contour coordinates of the area to be flanging formed obtained by the coordinate capture system as signals, control the multi-axis robotic arm to move the convex and concave molds to the area to be flanging formed and be in tangential contact with it.

[0054] Step S4: Keep the positions of the bottom of the box and the mold unchanged after positioning. At the same time, apply a certain pressure during the preheating process to make the bottom of the box fit tightly with the forming mold. The applied pressure remains unchanged during the preheating process. Heat the entire area to be flanging formed on the bottom through the mold heating. Start the heating device to heat the convex and concave molds respectively. At the same time, apply a certain pressure during the preheating process to make the bottom of the box fit tightly with the forming mold. The applied pressure remains unchanged during the preheating process. The heating device selects an electromagnetic heating coil to heat the convex and concave molds to further achieve the purpose of heating the area to be flanging formed.

[0055] Step S5: Monitor the temperatures of the convex and concave molds and the area to be flanging formed on the bottom of the box respectively through the temperature measurement system, and feedback the temperature data to the control system of the flexible forming unit in real time. Use thermocouples to measure the temperatures of the convex and concave molds and the area to be flanging formed respectively.

[0056] Step S6: After the temperatures of the convex-concave die and the forming area of the bottom of the box to be turned over reach a certain value, the control system sends commands to the multi-axis robotic arm to control the punch to move a certain distance to a determined position to achieve local forming of the part, and after forming, the die returns to the zero position. After the temperatures of the convex-concave die and the forming area of the bottom of the box to be turned over reach a certain value, the control system uses the coordinate of the feature point within the quadrant to be formed, the contour coordinate of the forming area of the bottom of the box to be turned over, the forming size of the bottom of the box to be turned over, and the temperature of the forming area of the bottom of the box to be turned over as the target signals, and the force displacement as the output control quantity, sends commands to the multi-axis robotic arm to control the punch to move a certain distance to a determined position to achieve local forming of the part, and after forming, the die returns to the zero position. When the quadrant where the forming area of the bottom of the box to be turned over is located changes, the hot hole-turning forming size and type change, or there are multiple local areas that need to be hole-turned and formed, specifically, without offsetting 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 achieve horizontal rotation of the bottom of the box, adjust it to the quadrant of the forming area of the bottom of the box to be turned over, and achieve hot hole-turning forming in different quadrants of the bottom of the box; different sizes of hot hole-turning forming of the bottom of the box can be achieved by replacing the specifications of the convex-concave die; by adjusting the position of the convex-concave die, specifically, when the type of hole to be turned over is an external hole, the punch is installed inside the entire bottom, and the die is installed outside the entire bottom. When the type of hole to be turned over becomes an internal hole, there is no need to flip the entire bottom, and only the corresponding die of the corresponding specification needs to be installed inside the bottom, and the corresponding punch of the corresponding specification needs to be installed outside the entire bottom to achieve internal hole-turning forming. Then, the process from Step S2 to Step S6 is executed in sequence, thereby realizing the heating deformation of hole-turning of different regions and different sizes of the entire bottom, that is, a set of devices realizes local flexible heating forming of different positions of metal curved surface components of different size levels of the entire bottom.

[0057] The control system in the flexible forming unit uses the coordinate of the feature point within the quadrant to be formed, the contour coordinate of the forming area of the bottom of the box to be turned over, the hot hole-turning forming size, and the temperature of the forming area of the bottom of the box to be turned over as the target signals, and the displacement of the convex-concave die as the output control quantity, controls the multi-axis robotic arm to realize the positioning and attitude adjustment of the convex-concave die in three-dimensional space, accurately controls the displacement of the convex and concave dies, and realizes high-precision hole-turning forming of each area of the bottom of the box. On the premise of keeping the bottom of the box in a horizontal state without offsetting or flipping the bottom of the box, local heating and high-precision hole-turning forming at any position on large-size and multi-size rotary shell metal components can be realized.

[0058] Further, in combination with Att Figure 1 to Att Figure 4 The flexible device and method for hot hole-turning forming of an ultra-large-size metal box bottom of the present invention are specifically described as follows:

[0059] Figure 1It is a schematic diagram of the flexible device for hot hole-flanging forming of the metal box bottom. First, the control system of the flexible forming unit takes the coordinates obtained by the coordinate capture system as signals to control the movement realized by the multi-axis robotic arm, so that the convex-concave die moves to the area to be hole-flanged and tangentially contacts it. Then, the electromagnetic heating coil in the heating device is started to heat the convex-concave die to achieve the purpose of heating the area to be hole-flanged. The temperature measurement system monitors the temperatures of the convex-concave die and the area of the box bottom to be hole-flanged respectively, and feeds the temperature data back to the control system of the flexible forming unit in real time. Finally, after the temperatures of the convex-concave die and the area of the box bottom to be hole-flanged reach a certain value, the control system takes the forming size of the hole to be flanged and the temperature of the area to be hole-flanged as target signals, takes the force displacement as the output control quantity, sends commands to the multi-axis robotic arm, and controls the punch to move a certain distance to a determined position to realize the local forming of the part.

[0060] Figure 2 It is a schematic diagram for obtaining the contour coordinates of the area to be hole-flanged of the metal box bottom. As shown in the figure, according to the quadrant where the area to be hole-flanged is located, a typical point within the quadrant of the area to be hole-flanged is selected as the feature point, and its absolute coordinates within this quadrant are defined. According to the 3D model of the box bottom, the relative coordinate values of each point on the contour of the area to be hole-flanged are further captured. Finally, the contour coordinates of the feature point within the quadrant to be formed and the area to be hole-flanged are obtained and fed back to the control system. Among them, the typical points include the points on the radial and axial arc lengths of the center spherical surface of the quadrant where the hole-flanging area of the box bottom is located.

[0061] Figure 3 It is a schematic diagram of the position change of the metal box bottom die. As Figure 3 (a) shows, due to the change in the position of the area to be hole-flanged, based on the contour coordinates of the area to be hole-flanged fed back by the coordinate capture system, it is necessary to control the position movement of the convex-concave die through the multi-axis robotic arm. It should be noted that if the size of the hole to be flanged changes, the die specifications need to be changed during this process; as Figure 3 (b) shows, when the type of hole to be flanged is an outward flanged hole, the punch is installed inside the whole bottom, and the die is installed outside the whole bottom. When the type of hole to be flanged changes to an inward flanged hole, there is no need to flip the whole bottom, and only the corresponding specification die needs to be installed inside the bottom, and the corresponding specification punch needs to be installed outside the whole bottom to realize the inward flanged hole forming.

[0062] Figure 4 It is a schematic diagram of the position change of the metal box bottom. As Figure 4 (a) shows, according to the markings on the surface of the fixing device, align the quadrant markings of the box bottom to fix the box bottom; as Figure 4 (b) and Figure 4 (c) show, the slider is installed on the fixing device. When the area of the box bottom to be hole-flanged changes, the movement of the slider is controlled by the servo drive system in the fixing device unit 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 hole-flanged.

[0063] The present invention aims to solve problems such as difficult local hot forming, low forming accuracy, low forming stability, difficult temperature field control, and easy generation of cracking defects in ultra-large-sized integral thin-walled components.

[0064] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0065] The specific embodiments of the present invention have been described above. 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. Without conflict, the embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other.

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 spherical surface of the quadrant where the area to be punched holes is located along 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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