Composite material missile wing integral coating forming method

Abstract

The invention provides an integral coating forming method for a composite missile wing, which comprises the following steps of: sequentially paving a plurality of layers of carbon fiber cloth on the molded surface of a lower mold to form a lower skin, paving a layer of adhesive film on the upper part and the lower part of the molded surface of a middle body of the missile wing to form an adhesive film intermediate body, and coating the adhesive film intermediate body with a layer of complete carbon cloth, sewing and reinforcing the upper-layer carbon cloth and the lower-layer carbon cloth which are wider than the side edges of the adhesive film intermediate, so that the adhesive film intermediate and the carbon cloth are tightly attached and clamped to prepare a sewn surrounding intermediate; and then placing the sewing surrounding intermediate on the lower skin on the molded surface of the lower mold, sequentially laying a plurality of layers of carbon fiber cloth on the upper surface of the sewing surrounding intermediate to form an upper skin, and then closing the mold, curing and molding, and demolding to obtain the product. The integrity of the missile wing structure can be enhanced, and the defects such as layering and debonding are effectively avoided; and by adopting a sewing reinforcement mode, the problem of front edge fragmentation can be improved, the product quality is obviously improved, and the product scrap cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of manufacturing composite material missile wings for aviation, and in particular relates to an integral overmolding method for composite material missile wings. Background Art

[0002] Existing composite missile wings are mostly sandwich structures to achieve the goal of lightweight. The intermediate is a PMI foam structure or a metal structure or a honeycomb structure, and the upper and lower skins are made of carbon fiber composite materials. The current molding method mostly adopts compression molding. The intermediate is bonded to the upper and lower skins through a film, and its bonding strength is limited. During the mission flight of the missile wing, it is easy to cause debonding, resulting in interface stratification, debonding of the intermediate, damage to the wing surface structure, etc., affecting the overall life of the missile wing. In addition, the thickness of the leading edge of the missile wing is particularly thin, and the intermediate is made of foam, honeycomb and other materials, which are thin and easy to break during processing. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides the following technical solutions:

[0004] A composite material missile wing integral overmolding method, comprising:

[0005] S1. Mold preparation: Place the mold on a platform for standby use, wherein the mold includes a lower mold and an upper mold;

[0006] S2. Lower skin layer: laying multiple layers of carbon fiber cloth on the surface of the lower mold to form the lower skin;

[0007] S3. Preparation of sutured encircled intermediates:

[0008] Laying a layer of adhesive film on the upper and lower intermediate surfaces of the wing to form an adhesive film intermediate, and then wrapping the adhesive film intermediate with a complete layer of carbon cloth;

[0009] After wrapping is completed, the upper and lower carbon cloths wider than the sides of the film intermediate are stitched and reinforced by stitching equipment, so that the film intermediate and the carbon cloth are tightly clamped to obtain a stitched and surrounded intermediate;

[0010] S4. Upper skin layer: The stitched enclosed intermediate is placed on the lower skin on the lower model surface, and multiple layers of carbon fiber cloth are sequentially laid on the upper surface of the stitched enclosed intermediate to form the upper skin;

[0011] S5.Mold closing;

[0012] S6. Curing and molding;

[0013] S7. Demoulding, trimming burrs, and obtaining the product.

[0014] Furthermore, the intermediate body of the wing is a PMI foam structure, a metal structure or a honeycomb structure.

[0015] Further, in S2, four to eight layers of carbon fiber cloth are sequentially laid on the surface of the lower mold to form a lower skin.

[0016] Further, in S2, the laying angle of the carbon fiber cloth on the molding surface of the lower mold is 0 / 90°.

[0017] Further, in S3, the wrapping method is to first spread the carbon cloth flat, place the film intermediate on the right half of the carbon cloth, and reserve 8mm stitching margins on the upper side, lower side, and right side of the entire film intermediate and the corresponding sides of the carbon cloth respectively; then bend the left half of the carbon cloth and turn it up to cover the upper surface of the film intermediate and call it the upper carbon cloth, and the right half of the carbon cloth originally pressed under the film intermediate is called the lower carbon cloth, and the upper and lower carbon cloths completely wrap the film intermediate.

[0018] Furthermore, in S3, the suture width is 8 mm.

[0019] Further, in S4, four to eight layers of carbon fiber cloth are sequentially laid on the upper surface of the sewn enclosed intermediate body to form an upper skin.

[0020] Further, in S4, the ply angle of the carbon fiber cloth on the upper surface of the stitched surrounding intermediate body is 0 / 90°.

[0021] Further, in S6, the curing method is hot pressing molding, and the pressure is applied to 0.2MPa at the beginning; the temperature is raised to 85°C, the heating rate is ≤3°C / min, and the temperature is kept for 30±5min; the temperature is then raised to 120±5°C, and the temperature is kept for 120min; after the insulation is completed, the temperature is lowered to below 60°C, the pressure is released and the mold is demolded, and the cooling rate is ≤2.5°C / min.

[0022] The present invention can enhance the integrity of the wing structure and effectively avoid defects such as delamination and debonding; the molding method is not limited by the process and can be applicable to a variety of molding processes; the use of suture reinforcement can improve the leading edge fragmentation problem, significantly improve the quality of the product, and reduce the cost of product scrapping. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings that constitute a part of the present invention are used to provide further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 It is a schematic diagram of the molding structure;

[0025] Figure 2 Schematic diagram of the structure of carbon cloth;

[0026] Figure 3This is a schematic diagram of carbon cloth wrapping;

[0027] Figure 4 Schematic diagram of the sutured encirclement of the midbody. DETAILED DESCRIPTION

[0028] 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.

[0029] Embodiment 1:

[0030] S1. Mold preparation: Place the mold on a platform for standby use, wherein the mold includes a lower mold and an upper mold;

[0031] S2. Lower skin layer: Figure 1 As shown, four layers of carbon fiber cloth are sequentially laid on the surface of the lower mold 1 to form the lower skin 5, with a laying angle of 0 / 90°;

[0032] S3. Preparation of sutured encircled intermediates:

[0033] The intermediate body of the wing is a PMI foam structure, and a layer of film is applied to the upper and lower surfaces of the intermediate body to form a film intermediate body 3-2, that is, the film intermediate body 3-2 is an intermediate body with a layer of film attached to the entire outer surface; then, the following method is used: Figure 2 A complete layer of carbon cloth 3-1 is shown to wrap the film intermediate 3-2, and the wrapping method is shown in FIG. Figure 3 As shown, the carbon cloth 3-1 is first spread out, and the adhesive film intermediate 3-2 is placed on the right half of the carbon cloth, and 8mm stitching margins 3-3 are reserved for the upper side, lower side, and right side of the entire adhesive film intermediate 3-2 and the corresponding sides of the carbon cloth 3-1; then the left half of the carbon cloth 3-1 is bent and turned up to cover the upper surface of the adhesive film intermediate 3-2 and is called the upper carbon cloth, and the right half of the carbon cloth originally pressed under the adhesive film intermediate 3-2 is called the lower carbon cloth, and the upper and lower carbon cloths completely wrap the adhesive film intermediate 3-2;

[0034] After wrapping is completed, the upper and lower layers of carbon cloth that are wider than the upper, lower and right sides of the film intermediate 3-2 are stitched and reinforced using a stitching device. The stitching width is 8mm, so that the film intermediate 3-2 and the carbon cloth 3-1 are tightly clamped to obtain a stitched surrounding intermediate 3; since a complete piece of carbon cloth is used, the upper and lower layers of carbon cloth are formed by bending and dividing on the left side of the film intermediate 3-2, so the left side does not need to be stitched and reinforced.

[0035] S4. Upper skin layer: Figure 1 As shown, the sewn enclosed intermediate body 3 is placed on the lower skin 5 on the surface of the lower mold 1, and four layers of carbon fiber cloth are sequentially laid on the upper surface of the sewn enclosed intermediate body 3 to form an upper skin 4, with a laying angle of 0 / 90°;

[0036] S5.Mold closing, such as Figure 1 As shown, the upper mold 2 and the lower mold 1 of the mold are molded together;

[0037] S6. Curing molding, the curing method is hot pressing molding, start with pressurization, pressurization to 0.2MPa. Heat up to 85℃, heating rate ≤3℃ / min, keep warm for 30±5min; then heat up to 120±5℃, keep warm for 120min. After the insulation is completed, cool down to below 60℃, release pressure and demould, cooling rate ≤2.5℃ / min.

[0038] S7. Demolding: Take the solidified product out of the mold, trim the burrs, and obtain the product.

[0039] Embodiment 2:

[0040] The differences between this embodiment and Embodiment 1 include:

[0041] In S2, five layers of carbon fiber cloth are laid in sequence to form the lower skin;

[0042] In the S4, five layers of carbon fiber cloth are laid in sequence to form the upper skin.

[0043] Comparison of embodiments: Embodiment 1 and Embodiment 2 were subjected to interlaminar shear tests according to the ASTM C273 test standard, and the samples of the two embodiments were analyzed with the interlaminar shear strength obtained in the test. Under the same test method, the same material, the same carbon cloth, and the same curing parameters, it can be seen from the table below that the interlaminar shear strength of Embodiment 1 is better than that of Embodiment 2. After adopting the new method, the interface strength of the product is stronger, and the interface performance of the product is improved.

[0044] Example 1 Example 2 Interlaminar shear strength / MPa 2.34 1.80

[0045] 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 composite material wing integral overmolding method, characterized in that: include: S1. Mold preparation: Place the mold on a platform for standby use, wherein the mold includes a lower mold and an upper mold; S2. Lower skin layer: laying multiple layers of carbon fiber cloth on the surface of the lower mold to form the lower skin; S3. Preparation of sutured encircled intermediates: Laying a layer of adhesive film on the upper and lower intermediate surfaces of the wing to form an adhesive film intermediate, and then wrapping the adhesive film intermediate with a complete layer of carbon cloth; After wrapping is completed, the upper and lower carbon cloths wider than the sides of the film intermediate are stitched and reinforced by stitching equipment, so that the film intermediate and the carbon cloth are tightly clamped to obtain a stitched and surrounded intermediate; S4. Upper skin layer: The stitched enclosed intermediate is placed on the lower skin on the lower model surface, and multiple layers of carbon fiber cloth are sequentially laid on the upper surface of the stitched enclosed intermediate to form the upper skin; S5.Mold closing; S6. Curing and molding; S7. Demoulding, trimming burrs, and obtaining the product.

2. The composite material wing integral overmolding method according to claim 1, characterized in that: The intermediate body of the wing is a PMI foam structure, a metal structure or a honeycomb structure.

3. The composite material wing integral overmolding method according to claim 1, characterized in that: In S2, four to eight layers of carbon fiber cloth are laid sequentially on the surface of the lower mold to form the lower skin.

4. The composite material missile wing integral overmolding method according to claim 1, characterized in that: In S2, the layup angle of the carbon fiber cloth on the molding surface of the lower mold is 0 / 90°.

5. The composite material missile wing integral overmolding method according to claim 1, characterized in that: In S3, the wrapping method is to first spread the carbon cloth flat, place the film intermediate on the right half of the carbon cloth, and reserve 8mm stitching margins for the upper side, lower side, and right side of the entire film intermediate and the corresponding sides of the carbon cloth respectively; then bend the left half of the carbon cloth and turn it up to cover the upper surface of the film intermediate and call it the upper carbon cloth, and the right half of the carbon cloth originally pressed under the film intermediate is called the lower carbon cloth, and the upper and lower carbon cloths completely wrap the film intermediate.

6. The composite material missile wing integral overmolding method according to claim 1, characterized in that: In S3, the suture width is 8 mm.

7. The composite material missile wing integral overmolding method according to claim 1, characterized in that: In S4, four to eight layers of carbon fiber cloth are sequentially laid on the upper surface of the stitched enclosed intermediate body to form an upper skin.

8. The composite material missile wing integral overmolding method according to claim 1, characterized in that: In S4, the carbon fiber cloth is laid at a ply angle of 0 / 90° on the upper surface of the stitched surround intermediate body.

9. The composite material missile wing integral overmolding method according to claim 1, characterized in that: In S6, the curing method is hot pressing molding, and the pressure is applied to 0.2MPa at the beginning; the temperature is raised to 85℃, the heating rate is ≤3℃ / min, and the temperature is kept for 30±5min; the temperature is then raised to 120±5℃, and the temperature is kept for 120min; after the insulation is completed, the temperature is lowered to below 60℃, the pressure is released and the mold is demolded, and the cooling rate is ≤2.5℃ / min.

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