A method for bending and forming ultra-thick, high-ribbed CNC milled mesh wall panels of aluminum alloy

Abstract

This invention relates to a method for bending and forming ultra-thick, high-ribbed aluminum alloy grid panel using CNC milling, belonging to the field of advanced manufacturing technology. The method includes: CNC milling the sheet material to create a grid pattern; processing filler and pads, processing filler material and pads according to the grid shape, size, and quantity; fixing the filler and pads, placing the filler into the grid, and then covering the grid with the pads to form the panel; and material placement and alignment. This invention achieves the bending and forming of ultra-large grid-patterned sheet materials by establishing reasonable rolling bending process parameters, solving the problem of manual alignment for ultra-large panel construction.

Description

Technical Field

[0001] This invention relates to a method for bending and forming ultra-thick aluminum alloy high-rib CNC milled mesh wall panels, belonging to the field of advanced manufacturing technology. Background Technology

[0002] There are two common processing methods for mesh panels: chemical milling and numerical milling. Numerical milling involves first machining the mesh from a flat sheet and then rolling it. Compared to traditional chemical milling, this is a green manufacturing method and can also achieve some weight reduction. The short shell panel of the 9.5m launch vehicle has a deep mesh and high ribs, with a diameter of 9.5m. It is made of 6 welded panels, with a maximum panel thickness of 45mm, rib width of 16mm, and mesh rib depth of 38mm. It employs a technique of first machining the mesh and then bending it. However, there is a lack of sufficient theoretical calculation and evaluation of the internal stress-strain state, plastic deformation distribution, residual stress, and springback after machining the sheet metal. The straightness accuracy of the generatrix is ​​poor after rolling, and the thin-walled, high-height rib mesh is susceptible to instability and deformation. Therefore, it is necessary to develop suitable filling schemes, rolling process parameters, and process-aided rib design schemes to improve forming accuracy.

[0003] There is still a gap in the domestic aerospace field for the rolling and bending processing of ultra-large and ultra-thick high-rib milled panels. Breakthroughs are needed in the technology for preventing instability during rolling and bending of high-rib thin-walled mesh panels. Traditional manual finishing methods cannot meet the precision requirements of the panels. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a bending forming method for ultra-thick aluminum alloy high-rib milled mesh wall panels, thereby improving product quality and reliability.

[0005] The solution of the present invention is:

[0006] A method for bending and forming an ultra-thick, high-ribbed, numerically milled mesh wall panel made of aluminum alloy, comprising:

[0007] CNC milling of sheet metal: CNC milling of raw materials to create a grid pattern;

[0008] Processing fillers and pads: Process filler materials and pads according to the grid shape, size and quantity. The outer dimensions of the filler are 0.4-0.6mm smaller than the three-dimensional dimensions of the grid shape.

[0009] Fixing the packing and the pad: Place the packing into the grid, and then cover the grid with the pad to form a wall panel;

[0010] Material feeding and alignment: Using a four-axis roller press, the two middle large shafts press the wall plate together. Rotate the roller to move the wall plate left and right repeatedly to place the wall plate into the middle two shafts of the four-axis roller press. After alignment, adjust the upper large shaft to press the wall plate together. Rotate the roller to adjust the vertical center line of the roller to be perpendicular to the long side of the wall plate. Adjust the left roller to contact the surface of the wall plate and record the vertical distance H between the center of this roller and the center of the middle large roller. At the same time, adjust the right roller to keep its center distance H from the center of the middle large roller.

[0011] Roll bending: After the material is fed and aligned and the value H is recorded, adjust the left roller to rise vertically a distance h1; rotate the two middle large shafts to move the wall panel from left to right. Stop rolling when the position of the wall panel with the two middle shafts is 90-110mm away from the left. Adjust the right roller to rise (h1+h1), and rotate the two middle large shafts to move the wall panel from right to left. When the wall panel starts to curve, record the roller distance H at this time. Continue to adjust the roller to rise continuously. During the rolling bending process, use a template to continuously check the change of the wall panel's curvature. Stop rolling bending when it is in contact with the wall panel.

[0012] Furthermore, the filler material is polypropylene.

[0013] Furthermore, the upward distance h1 of the roller before arc initiation is 20-30mm.

[0014] Furthermore, the curvature of the wall panel changes non-linearly from a flat plate to an arc and then to a rolled bend.

[0015] Furthermore, the wall panel begins to curve after at least four roll bends.

[0016] Furthermore, the roller rise distance h1 after the arc is initiated is adjusted by 5-10mm, and after at least 6 rounds of rolling, the arc of the wall panel fits the template.

[0017] Furthermore, the roller rising distance h1 is adjusted to 2-3mm, and the wall panel is formed by at least 4 rolling bends.

[0018] Furthermore, it also includes precision measurement, measuring the straightness of the busbar every 90-100mm along the curvature of the wall panel, and moving the wall panel from left to right along the curvature to detect the curvature.

[0019] Furthermore, the straightness of the busbar is greatest at the grid area.

[0020] Furthermore, this also includes panel alignment, which involves tapping the middle part of the panel along the curvature to make the gap between the panel curvature and the template 2-3mm, and the straightness of the generatrix 1-3mm.

[0021] The advantages of this invention compared to the prior art are:

[0022] (1) The mesh filler of this invention solves the defects of unstable deformation of mesh ribs and thin wall during the rolling bending process of high-strength thin-walled plates. By formulating reasonable rolling bending process parameters, the bending and forming of ultra-large mesh plates is realized, and the problem of manual shaping of ultra-large plates is solved.

[0023] (2) The present invention uses a roll bending forming method to achieve the bending forming of ultra-large size wall panels. This method has high technical maturity and improves product quality and reliability. Attached Figure Description

[0024] Figure 1 This invention relates to the wall panel bending process;

[0025] Figure 2 This is a schematic diagram of the wall panel grid structure and auxiliary ribs of the present invention;

[0026] Figure 3 This is a schematic diagram of the wall panel mounting of the present invention;

[0027] Wherein, 1-upper axis; 2-left axis; 3-left side platform;

[0028] Figure 4 This is a schematic diagram of the roller spacing of the present invention. Detailed Implementation

[0029] The present invention will be further described below with reference to the embodiments.

[0030] A method for bending and forming ultra-thick aluminum alloy high-rib milled mesh wall panels, such as... Figure 1 As shown, it includes:

[0031] (1) CNC milling of sheet metal: Using 1400*6000*45mm raw material, CNC milling is performed on the mesh, such as... Figure 2 As shown, the width of the process auxiliary ribs is 15mm, the same as the rib height of the part, and the spacing between two auxiliary ribs is 100mm; the wall thickness of the grid ribs in the arc direction is 12mm, and the grid has local rounded corner optimization. The diameter of the corner relief grooves of the grid is Φ10mm, and the grid depth is 38mm;

[0032] (2) Processing of filler and pad: The filler is processed according to the shape, size and quantity of the grid. Polypropylene is selected as the filler material. The outer dimensions of the filler are processed according to the three-dimensional dimensions of the grid shape minus 0.5mm to prevent the grid from curving and squeezing the filler during rolling, causing it to get stuck in the grid and unable to be removed. The pad is processed according to the size of 1400*6000*5mm;

[0033] (3) Fixing the packing and pad: Place the packing into the grid, then cover the top of the wall panel with the pad, covering the grid, and use tape or plastic film to bind the wall panel and the pad together.

[0034] (4) Feeding and alignment: A four-axis rolling mill is used, the structure of which is as follows: Figure 3 As shown. The two large shafts in the middle are responsible for pressing the sheet metal, rotating and rolling the sheet metal repeatedly left and right. The sheet metal is hoisted and placed into the two middle shafts of the equipment. After alignment, the upper large shaft is adjusted to press the wall panel. The rollers are rotated to adjust their vertical center line to be perpendicular to the long side of the wall panel, and this state is maintained throughout the forming process. The left roller is adjusted to contact the wall panel surface. At this time, the vertical distance H between the center of this roller and the center of the middle large roller is recorded. Simultaneously, the right roller is adjusted to maintain its center distance H from the center of the middle large roller. For example... Figure 4 As shown;

[0035] (5) Roll bending: After the material feeding and alignment processes are completed and the value H is recorded, adjust the left roller to rise vertically a distance h1 and record the value h1 at this time. Rotate the two middle large shafts to move the sheet material from left to right. Stop rolling when the two middle shafts are engaged and the sheet material is about 100mm away from the left side. Adjust the right roller to rise (h1+h1) and rotate the two middle large shafts to move the sheet material from right to left. Repeat the above steps. When the sheet material begins to curve noticeably, record the roller distance H at this time. At this time, the wall panel roll bending and curvature starting work is completed. Continue to adjust the roller to rise and repeat the above processing process. During the roll bending process, continuously use a template to check the change in the curvature of the sheet material. Stop rolling when it is in contact with the sheet material.

[0036] Roll bending parameters determined:

[0037] Before the arc is initiated, the roller rises a distance h1 (20-30mm). Panel bending is a process of gradual change in the curvature of the sheet material. From the flat surface to the start of the arc and the completion of the bending, the change in curvature is non-linear. The arc initiation stage is crucial and has a significant impact on the entire processing. Too small an arc initiation will result in more bending passes and longer processing time; too large an arc will cause localized reductions in the curvature of the sheet material, requiring repeated adjustments that are difficult to make. Based on the panel size and thickness, a roller rise distance of 20-30mm before each arc initiation is reasonable. The panel begins to arc after four bending passes.

[0038] The roller rise distance h1 between the bending passes is adjusted by 5-10mm after the initial arc. After 6 bending passes, the curvature of the board basically matches the sample. Subsequently, the roller rise distance h1 is adjusted by 2-3mm, and after 4 bending passes, the curvature of the board basically meets the requirements.

[0039] (6) Precision Measurement: Remove the wall panel and stand it upright. Use a template and a steel ruler to measure the straightness of the generatrix. Place the steel ruler against the surface of the wall panel and measure every 100mm along the curvature of the wall panel. Use the template to measure every 100mm along the vertical direction of the wall panel, and move the template from left to right along the curvature to check the curvature. The measurement results show that the maximum straightness of the generatrix at the grid area is 4mm. The maximum gap between the curvature and the template is 5mm, approximately 800-1000mm from the ends on both sides.

[0040] (7) Panel Shaping: Panel shaping employs a combination of manual and mechanical methods. A top-mounted bed is used to shape the busbars. Based on the panel's deformation, the panel is conveyed to the designated position via a ground-based transfer device. The middle slider rises to the top, and the side lifting transmission device sends the shaping hydraulic cylinder to the set position. The piston rod of the hydraulic cylinder extends outward to the set position to shape the panel's busbars. Traditional manual hammering is used to adjust the busbar straightness. The two vertical edges of the panel are placed on the ground, and a hammer is used to continuously strike the middle part of the panel along the curvature. After shaping, the gap between the panel's curvature and the template is 2-3mm, and the busbar straightness is 2mm, meeting the accuracy requirements.

[0041] This invention, a mesh filler, solves the problem of unstable deformation of mesh ribs and thin walls during the rolling bending process of high-strength thin-walled plates. By formulating reasonable rolling bending process parameters, it realizes the bending and forming of ultra-large mesh plates and solves the problem of manual shaping of ultra-large plates.

[0042] This invention uses a roll bending forming method to achieve the bending forming of ultra-large size wall panels. This method has high technical maturity and improves product quality and reliability.

[0043] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for bending and forming an ultra-thick aluminum alloy high-rib milled mesh wall panel, characterized in that, The maximum thickness of the wall panel is 45mm, the width of the reinforcing ribs is 16mm, and the depth of the mesh reinforcement is 38mm, including: CNC milling of sheet metal: CNC milling of raw materials to create a grid pattern; Processing fillers and pads: Process filler materials and pads according to the grid shape, size and quantity. The outer dimensions of the filler are 0.4-0.6mm smaller than the three-dimensional dimensions of the grid shape. Fixing the packing and the pad: Place the packing into the grid, and then cover the grid with the pad to form a wall panel; Material feeding and alignment: A four-axis roller press is used, which includes two middle axes, a left roller, and a right roller. The two middle axes press the wall plate, and the rotating roller moves the wall plate left and right repeatedly to place the wall plate into the two middle axes of the four-axis roller press. After alignment, the upper ends of the two middle axes are adjusted to press the wall plate. The roller is rotated to adjust the vertical center line of the roller to be perpendicular to the long side of the wall plate. The left roller is adjusted to contact the surface of the wall plate, and the value H of the vertical distance between the center of the left roller and the center of the two middle axes is recorded. At the same time, the right roller is adjusted to keep its center distance from the center of the two middle axes also H. Roll bending: After the material is fed and aligned and the value H is recorded, adjust the left roller to rise vertically a distance h1; rotate the two middle rollers to move the wall panel from left to right. Stop rolling when the position of the wall panel with the two middle rollers is 90-110mm away from the left. Adjust the right roller to rise (h1+h1) and rotate the two middle rollers to move the wall panel from right to left. Record the roller distance H when the wall panel starts to curve. Continue to adjust the roller to rise. During the rolling process, use a template to continuously check the change of the wall panel's curvature. Stop rolling when the template is in contact with the wall panel. The roller rise distance h1 before arc initiation is 20-30mm; The wall panel begins to curve after at least four roll bends. After the arc is started, the roller rise distance h1 is adjusted by 5-10mm. After at least 6 rounds of rolling, the arc of the wall panel fits the template. Subsequently, the roller rise distance h1 is adjusted to 2-3mm, and the wall panel is formed by at least 4 rounds of rolling.

2. The method for bending and forming an ultra-thick, high-ribbed, multi-milled mesh wall panel of aluminum alloy according to claim 1, characterized in that, The filler material is polypropylene.

3. The method for bending and forming an ultra-thick aluminum alloy high-rib milled mesh wall panel according to claim 1, characterized in that, The curvature of the wall panel changes non-linearly from flat to curved to rolled.

4. The method for bending and forming an ultra-thick aluminum alloy high-rib milled mesh wall panel according to claim 1, characterized in that, It also includes precision measurement, measuring the straightness of the busbar every 90-100mm along the curvature of the wall panel, and moving the wall panel from left to right along the curvature to detect the curvature.

5. The method for bending and forming an ultra-thick, high-ribbed, multi-milled mesh wall panel of aluminum alloy according to claim 1, characterized in that, The straightness of the busbar is greatest at the grid area.

6. The method for bending and forming an ultra-thick, high-ribbed, multi-milled mesh wall panel of aluminum alloy according to claim 1, characterized in that, It also includes wall panel alignment, which involves tapping the middle part of the wall panel along the curvature to make the gap between the wall panel curvature and the template 2-3mm, and the straightness of the generatrix 1-3mm.

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