Co-bonding forming method for solving wrinkles of pre-laid product through uniform pressure transmission

Abstract

The invention discloses a co-bonding forming method for solving wrinkles of a pre-laid product through uniform pressure transfer, and the method comprises the steps of selection of a thin film layer, preparation before laying, laying of the thin film layer and packaging and curing. The method can solve the problem that the skin at the end of the edge where the co-glued cured composite material stiffened wallboard part intersects with the uncured pre-laid layer prepreg is wrinkled, achieves forming of the co-glued composite material stiffened wallboard, solves the problem of fiber wrinkling of the pre-laid layer part in a co-glued product, and has wide application and popularization value.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material reinforced wallboard forming, and in particular relates to a co-bonding forming method for solving wrinkles of pre-laid products by uniformly transmitting pressure. Background Art

[0002] Composite material reinforced panel structures are widely used in aerospace, automobile, shipbuilding and other fields due to their high strength, high stiffness, light weight, good fatigue life and durability. Through the design of reinforced structure, the reinforced panel structure can not only effectively resist external loads, increase structural strength and stiffness, and improve the bearing capacity of the structure under complex working conditions, but also improve the durability and fatigue life of parts and components, and extend the service life of parts and components. At the same time, by using lightweight composite materials as the reinforced panel material, the weight of the part structure is significantly reduced, which improves the overall efficiency and performance of the aircraft or vehicle.

[0003] At present, composite reinforced wall panel structures mainly adopt the co-bonding molding process, which first solidifies and molds L-shaped, T-shaped, I-shaped or Ω-shaped parts, then positions the solidified parts on the uncured pre-laid prepreg, and finally packages and solidifies them. Since the bottom plate of the solidified parts has a certain thickness, the vacuum bag is easy to bridge the side of the bottom plate of the solidified parts during packaging, resulting in fiber wrinkles at the interface where the uncured pre-laid prepreg intersects with the bottom plate of the solidified parts after curing, thereby affecting product performance; To solve this problem, a commonly used method is to place putty strips wrapped with isolation film around the sides of the cured part base plate to avoid vacuum bag bridging. However, since the putty strips cannot solve the pressure transmission problem well, skin wrinkles cannot be completely avoided. At the same time, the putty strips can only be used once and the cost is relatively high. For this reason, we propose a co-bonding molding method that uniformly transmits pressure to solve the wrinkles of pre-laid products. Summary of the invention

[0004] The object of the present invention is to provide a co-bonding molding method for solving the wrinkles of pre-laid products by uniform pressure transmission, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a co-bonding molding method for uniformly transmitting pressure to solve the wrinkles of pre-laid products, comprising the following steps: A. Film layer selection: According to the requirements of the co-bonding and forming of the composite material reinforced wall panel, select the film layer to be superimposed on the thickness of the bottom plate of the cured composite material reinforced wall panel part; B. Preparation before laying: Placing the uncured pre-laid prepreg on a forming tool, positioning and laying the cured composite material reinforced wall panel part on the uncured pre-laid prepreg, and laying a sacrificial layer at the intersection edge of the cured composite material reinforced wall panel part and the uncured pre-laid prepreg; C. Laying the film layer: A film layer is superimposed and laid on the sacrificial layer at the intersection edge of the cured composite material reinforced wall panel part and the uncured pre-laid prepreg material, and the film layer is aligned with the side width of the cured composite material reinforced wall panel part and decreases to the sacrificial layer in sequence; D. Packaging and curing: The cured composite reinforced wall panel parts with laid film layer and the uncured pre-laid prepreg are packaged together, and the isolation film and breathable felt are laid on the cured composite reinforced wall panel parts in turn. The cured composite reinforced wall panel parts with laid film layer and the uncured pre-laid prepreg are then packaged by vacuum bag and vacuumed. The intersection edges of the cured composite reinforced wall panel parts and the uncured pre-laid prepreg are vacuum bagged or micro-pleated, and the uncured pre-laid prepreg is cured according to the curing requirements, so as to finally obtain the composite reinforced wall panel co-bonded molded parts.

[0006] Preferably, the film layer in step A is a film layer made of a reusable rubber material, and has an operating temperature range of 100-200°C.

[0007] Preferably, the single layer thickness of the thin film layer in step A is m, and m=0.1-0.5 mm.

[0008] Preferably, the laying width of the sacrificial layer in step B is amm, the laying width of the bottom film layer in step C is bmm, and b<a.

[0009] Preferably, the stacking thickness n of the film layer in step C is greater than or equal to the thickness of the bottom plate of the cured composite reinforced wall panel part, and the thickness difference between the film layer and the bottom plate of the cured composite reinforced wall panel part is less than or equal to the thickness m of the single film layer, that is, ns≤m, where s represents the thickness of the bottom plate of the cured composite reinforced wall panel part.

[0010] Preferably, in step C, the film layer is aligned with the side width of the cured composite material reinforced wall panel part, and the width is decreased in sequence to c, that is, c=(bd) / (n / m-1); Where b is the width of the bottom film layer; d is the width of the topmost film layer.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The present invention can solve the problem of skin wrinkles at the edge ends of the co-bonded cured composite material reinforced wall panel parts and the uncured pre-laid prepreg by placing a film layer with a gradually varying thickness at the ends of the co-bonded cured composite material reinforced wall panel parts, thereby realizing the molding of the co-bonded composite material reinforced wall panel and solving the fiber wrinkle problem of the pre-laid parts in the co-bonded products, and has wide application and promotion value; The main advantages of this technology are: (1) The thin rubber film layer can be used to form parts at 100-200°C, and the stacking method can match the cured composite reinforced wall parts of various thicknesses; (2) Uniform pressure transmission can be achieved by gradually laying down the film layer and taking advantage of the characteristics of the film layer material itself; (3) The thin rubber film layer can be reused, thus reducing the molding cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the molding structure of the present invention; Figure 2 It is a schematic diagram of the film layer laying structure of the present invention.

[0013] In the figure: 1. Molding tooling; 2. Uncured pre-laid prepreg; 3. Cured composite reinforced wall panel parts; 4. Film layer; 5. Sacrificial layer. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] See also Figure 1-Figure 2 The present invention provides a co-bonding and forming method for solving the wrinkles of pre-laid products by uniform pressure transmission, comprising the following steps: A. Film layer selection: According to the requirements of the co-bonding molding of the composite material reinforced wall panel, a film layer 4 to be superimposed on the bottom plate thickness of the cured composite material reinforced wall panel part 3 is selected. The film layer 4 is a film layer made of a reusable rubber material, and the use temperature range is 100-200°C. The film layer made of the rubber material is used to assist in the curing and molding of the co-bonding molded parts at 100-200°C. The single layer thickness of the film layer 4 is m, and m=0.1-0.5mm. The single layer thickness of the film layer 4 is relatively thin, which is convenient for superimposing on the bottom plate thickness of the cured composite material reinforced wall panel part 3, and can be reused, thereby reducing the molding cost; B. Preparation before laying: The uncured pre-laid prepreg 2 is placed on the forming tool 1, and the cured composite material reinforced wall panel part 3 is positioned and laid on the uncured pre-laid prepreg 2, and a sacrificial layer 5 is laid at the intersection edge of the cured composite material reinforced wall panel part 3 and the uncured pre-laid prepreg 2. The laying width of the sacrificial layer 5 is amm, and direct contact between the uncured pre-laid prepreg 2 and the film layer 4 is avoided; C. Laying the film layer: A film layer 4 is stacked and laid on the sacrificial layer at the intersection edge of the cured composite reinforced wall panel part 3 and the uncured pre-laid prepreg 2, the laying width of the bottom film layer 4 is bmm, and b<a, and the film layer 4 is aligned with the side width of the cured composite reinforced wall panel part 3 and decreases to the sacrificial layer in sequence, the stacking thickness n of the film layer is greater than or equal to the thickness of the bottom plate of the cured composite reinforced wall panel part, and the thickness difference between the film layer and the bottom plate of the cured composite reinforced wall panel part is less than or equal to the thickness m of the single film layer, that is, ns≤m, wherein s represents the thickness of the bottom plate of the cured composite reinforced wall panel part, and the film layer 4 is aligned with the side width of the cured composite reinforced wall panel part 3 and decreases in sequence to a width of c, that is, c=(bd) / (n / m-1); Where b is the width of the bottom film layer 4; d is the width of the topmost film layer 4; D. Packaging and curing: The cured composite reinforced wall panel part 3 with the laid film layer 4 and the uncured pre-laid prepreg 2 are packaged together, and the isolation film and breathable felt are laid on the cured composite reinforced wall panel part 3 in turn, and then the cured composite reinforced wall panel part 3 with the laid film layer 4 and the uncured pre-laid prepreg 2 are packaged by a vacuum bag and vacuumized, and the intersection edges of the cured composite reinforced wall panel part 3 and the uncured pre-laid prepreg 2 are vacuum-smoothed or micro-pleated. The micro-pleating treatment makes the intersection edges of the cured composite reinforced wall panel part 3 and the uncured pre-laid prepreg 2 gradually change. It is difficult to completely smooth the vacuum bag. The micro-pleating does not affect the molding quality and can reduce the packaging difficulty. The bridging and vacuum bag bursting problems can be avoided without special treatment. The uncured pre-laid prepreg 2 can be cured according to the curing requirements to finally obtain a composite reinforced wall panel co-bonded molded part.

[0016] The present invention solves the problem of skin wrinkles at the edge ends of the co-bonded cured composite material reinforced wall panel parts and the uncured pre-laid prepreg intersecting parts by placing a film layer with a gradually varying thickness at the ends of the co-bonded cured composite material reinforced wall panel parts, thereby realizing the molding of the co-bonded composite material reinforced wall panel. The main advantages of this technology are: (1) The thin rubber film layer can be used to form parts at 100-200°C, and the stacking method can match the cured composite reinforced wall parts of various thicknesses; (2) Uniform pressure transmission can be achieved by gradually laying down the film layer and taking advantage of the characteristics of the film layer material itself; (3) The thin rubber film layer can be reused, thus reducing the molding cost.

[0017] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A co-bonding molding method for solving the wrinkles of pre-laid products by uniform pressure transmission, characterized in that: The steps include: A. Film layer selection: According to the requirements of the co-bonding and forming of the composite material reinforced wall panel, select the film layer to be superimposed on the thickness of the bottom plate of the cured composite material reinforced wall panel part; B. Preparation before laying: Placing the uncured pre-laid prepreg on a forming tool, positioning and laying the cured composite material reinforced wall panel part on the uncured pre-laid prepreg, and laying a sacrificial layer at the intersection edge of the cured composite material reinforced wall panel part and the uncured pre-laid prepreg; C. Laying the film layer: A film layer is superimposed and laid on the sacrificial layer at the intersection edge of the cured composite material reinforced wall panel part and the uncured pre-laid prepreg material, and the film layer is aligned with the side width of the cured composite material reinforced wall panel part and decreases to the sacrificial layer in sequence; D. Packaging and curing: The cured composite reinforced wall panel parts with laid film layer and the uncured pre-laid prepreg are packaged together, and the isolation film and breathable felt are laid on the cured composite reinforced wall panel parts in turn. The cured composite reinforced wall panel parts with laid film layer and the uncured pre-laid prepreg are then packaged by vacuum bag and vacuumed. The intersection edges of the cured composite reinforced wall panel parts and the uncured pre-laid prepreg are vacuum bagged or micro-pleated, and the uncured pre-laid prepreg is cured according to the curing requirements, so as to finally obtain the composite reinforced wall panel co-bonded molded parts.

2. The co-bonding molding method for solving wrinkles of pre-laid products by uniform pressure transmission according to claim 1 is characterized by: The film layer in step A is a reusable film layer made of rubber material, and the operating temperature range is 100-200°C.

3. The co-bonding molding method for solving wrinkles of pre-laid products by uniform pressure transmission according to claim 1 is characterized in that: The film layer thickness in step A ranges from 0.1 to 0.5 mm.

4. The co-bonding molding method for solving wrinkles of pre-laid products by uniform pressure transmission according to claim 1 is characterized in that: The laying width of the sacrificial layer in step B is amm, the laying width of the bottom film layer in step C is bmm, and b<a.

5. The co-bonding molding method for solving wrinkles of pre-laid products by uniform pressure transmission according to claim 1 is characterized in that: The stacking thickness n of the film layer in step C is greater than or equal to the thickness of the bottom plate of the cured composite material reinforced wall panel part, and the thickness difference between the film layer and the bottom plate of the cured composite material reinforced wall panel part is less than or equal to the thickness m of the single film layer, that is, ns≤m, where s represents the thickness of the bottom plate of the cured composite material reinforced wall panel part.

6. The co-bonding molding method for solving wrinkles of pre-laid products by uniform pressure transmission according to claim 5 is characterized by: In step C, the film layer is aligned with the side width of the cured composite stiffened panel part and the width is decreased by c, that is, c=(bd) / (n / m-1); Where b is the width of the bottom film layer; d is the width of the topmost film layer.

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