Bending forming method for super-long, large, thick and high-density structure grid wall plate based on reverse compensation

Abstract

The invention provides a bending forming method for a super-long, large, thick and high-density structure grid wallboard based on reverse compensation. A plurality of triangular grids which are uniformly distributed are arranged on the surface of one side of the grid wallboard; the upper end and the lower end of the grid wall plate in the heading height direction are each provided with a grid suspension area. A row of triangular hollow grids, in the annular direction, of the grid wall plate can be divided into a first longitudinal rib area, an inter-rib triangular grid area and a second longitudinal rib area. The bending forming method comprises the following steps: S1, adding an auxiliary grid; an auxiliary grid is arranged in the suspended area; s2, optimizing the height of the auxiliary grid; s3, reverse compensation shape correction is carried out; s4, performing sectional progressive compensation gate pressure forming; and S5, the balance is removed. According to the method, the mode of plate machine and grid variable height structure optimization design, reversible deformation and partition progressive compensation is adopted, the forming process path and parameters are reasonably designed, and qualified products meeting the assembly requirement are produced.

Description

Technical Field

[0001] The invention belongs to the field of bending forming processing, and in particular relates to a bending forming method of an ultra-long, thick and high-density structure grid wall panel based on reverse compensation. Background Art

[0002] In order to effectively reduce the number of circumferential seam welding, ensure the rigidity of the tank and shorten the development cycle, the new generation of manned launch vehicle tank products adopt wall panels with ultra-long, thick, high rigidity and high-density structural characteristics. The maximum height of a single product is 6400mm and the maximum thickness is 36mm. The material used for this type of ultra-long, thick and high-density structural grid wall panel products is 2219-C10S aluminum alloy, and the product surface accuracy is required to be controlled within 3mm;

[0003] In view of the requirements of model product assembly and load-bearing, higher requirements are put forward for the forming accuracy of super-long, thick and high-rigidity cylinder section wall panels. In view of the production and development experience of conventional 2-meter-high wall panels, there are mainly the following difficulties in forming accuracy and production efficiency:

[0004] (1) The product structure is thick, the rigidity is high, the stress difference between the welding area and the mesh area is obvious, the forming springback is large, and it is difficult to ensure the accuracy of curvature and straightness;

[0005] (2) The product structure is uneven, the stiffness varies greatly, and the plastic strain values ​​generated by forming along the arc direction are different, which also makes it difficult to ensure the forming arc;

[0006] (3) The heading height is high and is affected by the length deflection deformation, making it more challenging to achieve high-precision control of straightness;

[0007] (4) During the forming process, the outer side of the ribs of the cylinder wall is easily deformed by extrusion, which affects the surface quality;

[0008] (5) The traditional single rolling method or gate pressure forming method cannot solve the problem of forming accuracy. In addition, due to the high altitude of the product parts, it is impossible to use the traditional manufacturing method of manual trimming to compensate for the trimming. Therefore, the original forming method is far from meeting the model requirements.

[0009] In the current model rockets, the external grid structure wall panels are usually formed by roll bending, press bending and other processes, which have the following disadvantages:

[0010] (1) Roll forming: This process mainly uses three-axis and four-axis linear roll forming processes. Due to the unevenness of the grid structure of the general wall panel during the forming process, the force is uneven during the forming process, and the forming accuracy is usually limited.

[0011] (2) Press-bending: A special bending machine drives the press head to perform local three-point bending deformation on the surface of the whole wall panel in segments along a certain trajectory, and finally the entire wall panel surface is formed into the desired shape. The basic principle is to rely on the accumulation of successive deformations to produce overall deformation.

[0012] Simply using roll bending or press bending has its disadvantages. Due to the long height of the parts, the forming process needs to resist the force majeure factors caused by the deflection and deformation of the parts themselves. After the parts are formed, the straightness difference of the generatrix along the height direction is obvious, and the maximum straightness gap can be as high as 18-20mm. Summary of the invention

[0013] In view of this, the present invention aims to propose a bending forming method for super-long, thick and high-density structural grid wall panels based on reverse compensation. By adopting the "flat machine plus grid variable height structure optimization design + reverse deformation + partition progressive compensation" method, the forming process path and parameters are reasonably designed to produce qualified products that meet the assembly requirements.

[0014] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0015] A method for bending and forming an ultra-long, thick and high-density structure grid wall panel based on reverse compensation, wherein a surface of one side of the grid wall panel is provided with a plurality of evenly distributed triangular grids; the grid wall panel is provided with grid hanging areas at both ends along the heading height direction;

[0016] A row of triangular hollow grids of the grid wall panel along the circumferential direction can be divided into a No. 1 longitudinal rib area, an inter-rib triangular grid area and a No. 2 longitudinal rib area;

[0017] The bending forming method comprises the following steps:

[0018] S1. Add auxiliary grids; set auxiliary grids in the suspended area;

[0019] S2, optimize the height of the auxiliary grid;

[0020] S3, reverse compensation correction;

[0021] S4, zoned progressive compensation gate pressure forming;

[0022] S5. Residue removal.

[0023] Furthermore, in step S1, auxiliary ribs are formed between a plurality of auxiliary grids;

[0024] A single-side margin area of ​​not less than 200 mm is added at both ends along the arc direction, and the margin area is removed after forming.

[0025] Furthermore, in step S2, the height of the auxiliary ribs is greater than the height of the triangular hollow grid.

[0026] Furthermore, in step S3, within the 1500mm area at both ends of the circumferential direction of the grid wall panel, the grid wall panel is shaped along the curvature direction, and the flat plate state is first formed to R8000-R10000 for pre-forming.

[0027] Furthermore, in step S4, during the forming process, the forming lower die is subjected to reverse ejection compensation, and the lower die can be divided into 17 areas for compensation correction, that is, the original mold is a horizontal straight lower die, and a flexible and adjustable compensation mechanism of 17 areas is adopted. The scheme adopted is that the closer to the middle position, the greater the upper ejection compensation, and the compensation method is based on the heading center, and a small amount of decreasing compensation is made along the two ends at a time.

[0028] Furthermore, in step S5, the arc length and the template are double-checked according to the preset margin size of the wall panel part, the margins on both sides are cut evenly, and the margins at both ends of the part are removed according to the marked positions.

[0029] Compared with the prior art, the bending forming method of the ultra-long, thick and high-density structure grid wall panel based on reverse compensation described in the present invention has the following advantages:

[0030] The present invention discloses a bending forming method for super-long, thick and high-density structural grid wall panels based on reverse compensation. According to the structural characteristics of super-long, thick and high-density structural grid wall panels and the deformation law of conventional forming, the forming path is matched by adopting the "flat machine plus grid variable height structure optimization design + reverse compensation shape correction + partition progressive compensation" method, and a reasonable forming path and process parameters are established. Flexible parameter compensation and adjustment are performed for different areas in the busbar direction, and according to the reverse deformation characteristics, the difficult-to-deform area is intervened in advance to form a bending forming method for super-long, thick and high-density structural grid wall panels, solidify the process parameter window, ensure the feasibility of the forming method, solve the problem of poor part precision, and ensure the product forming precision and surface quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0032] Figure 1 A schematic diagram of the deformation law of the outer surface of the super-long, thick and high-density structure grid wall panel along the generatrix direction according to an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of a suspended area according to an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of the ribs and the auxiliary grids provided in the embodiment of the present invention;

[0035] Figure 4 A partial cross-sectional view of the upper and lower auxiliary structures of the inter-rib triangular mesh area according to an embodiment of the present invention;

[0036] Figure 5 A partial cross-sectional view of the auxiliary structure of the upper and lower ends of the longitudinal rib position according to an embodiment of the present invention;

[0037] Figure 6 A schematic diagram of a reverse compensation shape correction and reverse shape correction bending line according to an embodiment of the present invention;

[0038] Figure 7 It is a schematic diagram of the progressive compensation method along the busbar on the outer surface of the super-long, thick and high-density structure grid wall panel described in an embodiment of the present invention.

[0039] Description of reference numerals:

[0040] 1. Suspended area; 2. Longitudinal ribs; 3. Triangular grid area between ribs; 4. Triangular grid; 5. Reverse correction bending line. DETAILED DESCRIPTION

[0041] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0042] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0044] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0045] When the super-long, thick, and high-density structural grid wall panels are gate-pressed or rolled without intervention, the basic deformation law along the generatrix direction of the outer surface after forming is that the curvature in the middle area is too large, and it is difficult to reach R2496, characterized by concave and olive-shaped; the curvature in the area 1500mm from the upper and lower ends to the upper and lower end ring reinforcement is too small; the curvature in the upper and lower end areas is too large; Figure 1 As shown;

[0046] Based on the above deformation law, the specific technical solution is as follows:

[0047] The product needs to consist of 6 pieces of barrel sections. There is a grid hanging area 1 in the upper and lower sections of the grid structure wall panel along the heading height direction. The upper and lower molds cannot be contacted during the forming process. It is difficult for the upper and lower ends of the heading to achieve the corresponding degree of support force deformation. The overall deformation law indicates that the arc of the hanging area 1 at the upper and lower ends of the heading is too large; Figure 2 As shown;

[0048] During the product forming process, the structure along the circumferential direction (i.e., the short side direction) can be roughly divided into two areas: the longitudinal rib 2 position structure and the inter-rib triangular mesh area 3. During the forming process, the general phenomenon is that the longitudinal rib 2 position produces deformation, which is usually 0.5mm-1mm more than the inter-rib triangular mesh area 3.

[0049] In summary, the original structure of the parts will lead to poor final precision, which has a great impact on the product forming and assembly precision. Therefore, before mechanical milling, the product structure is designed for process design and machined according to the optimized structure. The product structure optimization methods are as follows:

[0050] A method for bending and forming an ultra-long, thick and high-density structure grid wall panel based on reverse compensation, wherein a surface of one side of the grid wall panel is provided with a plurality of evenly distributed triangular grids 4; the grid wall panel is provided with grid suspension areas 1 at both upper and lower ends along the heading height direction;

[0051] A row of triangular hollow grids of the grid wall panel along the circumferential direction can be divided into two areas of the first longitudinal rib, three areas of the inter-rib triangular grid and two areas of the second longitudinal rib; Figure 3 As shown;

[0052] The bending forming method comprises the following steps:

[0053] S1. Add auxiliary grids; set auxiliary grids in the suspended area 1; in case the suspended area 1 is difficult to support the constraints, it is necessary to add auxiliary grids at the upper and lower ends of the heading to achieve the constraints and strong support effects, forming a uniformly distributed symmetrical grid;

[0054] S2. Optimize the height of the auxiliary grid. In view of the difference in forming force required for plastic deformation between the longitudinal rib 2 position structure and the inter-rib triangular grid area 3 during the forming process (characterized by different downward amounts), the compensatory auxiliary rib grid added to the suspended area 1 adopts a variable height feature design, that is, the heights of the auxiliary ribs corresponding to different areas are inconsistent, and according to previous production experience, the height of the added auxiliary grid ribs must be higher than the height of the main grid.

[0055] The force magnitude in the end area along the arc direction and the forming spacing match the relationship. It is necessary to increase the margin of no less than 200mm on one side for process optimization, and remove the margin area after subsequent forming.

[0056] like Figure 4 shown.

[0057] S3, reverse compensation correction; in order to solve the problem of small curvature in the 1500mm area of ​​the annular ribs at the upper and lower ends of the outer surface busbar, the flat machine is equipped with a rear grid wall panel, and the two areas are lateral reverse correction is performed, that is, before the part is bent, the area is corrected along the width direction (2516.63mm) of the wall panel, and the grid surface is flushed upwards. Figure 6 The framed area is bent and shaped multiple times along the direction of the arrow, and the flat plate is first formed to R8000-R10000 for pre-forming.

[0058] S4, partitioned progressive compensation gate pressure forming; in view of the fact that the super-long, thick and high-density structural grid wall panels are gate-pressed or rolled without intervention, after forming, the basic deformation law along the generatrix direction of the outer surface is that the curvature in the middle area of ​​about 4800mm is too large, it is difficult to reach R2496, and it is characterized by an olive-shaped concave shape. Therefore, it is considered to reversely eject the lower die during the forming process. The lower die can be divided into 17 areas for compensation correction, that is, the original mold is a horizontal straight lower die. By adopting a flexible and adjustable compensation mechanism of 17 areas, the plan is that the closer to the middle position, the greater the upper compensation, and the compensation method is based on the heading center, and a small amount of decreasing compensation is made along both ends, such as Figure 7 As shown. The forming die is a component of the bending machine.

[0059] S5. Removal of excess. Double check the arc length and the template according to the preset excess size of the wall panel parts, cut the excess on both sides evenly, and remove the excess at both ends of the parts according to the marked position.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A bending forming method of an ultra-long, thick and high-density structure grid wall panel based on reverse compensation, characterized in that: A surface of one side of the grid wall panel is provided with a plurality of evenly distributed triangular grids; the grid wall panel is provided with grid hanging areas at both upper and lower ends along the heading height direction; A row of triangular hollow grids of the grid wall panel along the circumferential direction can be divided into a No. 1 longitudinal rib area, an inter-rib triangular grid area and a No. 2 longitudinal rib area; The bending forming method comprises the following steps: S1. Add auxiliary grids; set auxiliary grids in the suspended area; S2, optimize the height of the auxiliary grid; S3, reverse compensation correction; S4, zoned progressive compensation gate pressure forming; S5. Residue removal.

2. The method for bending and forming an ultra-long, thick and high-density structure grid wall panel based on reverse compensation according to claim 1 is characterized in that: In step S1, auxiliary ribs are formed between a plurality of auxiliary grids; A single-side margin area of ​​not less than 200 mm is added at both ends along the arc direction, and the margin area is removed after forming.

3. The method for bending and forming an ultra-long, thick and high-density structure grid wall panel based on reverse compensation according to claim 2 is characterized in that: In step S2, the height of the auxiliary ribs is greater than the height of the triangular hollow grid.

4. The method for bending and forming an ultra-long, thick and high-density structure grid wall panel based on reverse compensation according to claim 1 is characterized in that: In step S3, within the 1500mm area at both ends of the circumferential direction of the grid wall panel, the grid wall panel is shaped along the curvature direction, and the flat plate state is first formed to R8000-R10000 for pre-forming.

5. The method for bending and forming an ultra-long, thick and high-density structure grid wall panel based on reverse compensation according to claim 1 is characterized in that: In step S4, during the forming process, the forming lower die is subjected to reverse ejection compensation. The lower die can be divided into 17 areas for compensation correction, that is, the original mold is a horizontal straight lower die. By adopting a flexible and adjustable compensation mechanism of 17 areas, the scheme adopted is that the closer to the middle position, the greater the upper ejection compensation. The compensation method is based on the heading center and a small amount of decreasing compensation is performed along the two ends.

6. The method for bending and forming an ultra-long, thick and high-density structure grid wall panel based on reverse compensation according to claim 1 is characterized in that: In step S5, the arc length and the template are double-checked according to the preset margin size of the wall panel parts, the margins on both sides are cut evenly, and the margins at both ends of the parts are removed according to the marked positions.

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