Method for accurately pre-burying metal part in large-thickness composite material

Abstract

The invention discloses a method for accurately pre-burying a metal part in a large-thickness composite material. The method comprises the following steps: determining the single forming thickness of the composite material; the total thickness of the composite prefabricated slabs is determined according to the product thickness and the height of the metal embedded part, and the number of the composite prefabricated slabs is calculated by combining the single forming thickness; composite material prefabricated plates are prepared, and each composite material prefabricated plate comprises two symmetrical plates; hole sites in the composite material prefabricated slab are machined; an inner skin is formed on the surface of the rotary body mold, the metal embedded parts are embedded into the composite material prefabricated plates, and the adjacent prefabricated plates are assembled on the rotary body mold in an up-down and left-right alternate splicing mode; a horizontal positioning tool is matched, so that the positioning precision of the metal embedded part is further ensured; and a product outer skin is laid on the surface of the composite material prefabricated slab, and after the product is cured, the product is demolded from the rotary body mold. According to the invention, the problem that the positioning precision of the internal metal embedded part is not accurate when a large-thickness composite material is formed on a rotary body mold is solved.

Description

Technical Field

[0001] This invention relates to the field of molding technology for thick composite materials containing embedded metal parts, and particularly to a method for precisely embedding metal parts in thick composite materials. Background Technology

[0002] As composite materials are used more and more widely, thick composite material products (thickness exceeding 50mm) are becoming more and more common, and the requirements for the positioning accuracy of metal embedded parts in these products are also increasing.

[0003] A common method for embedding metal parts in composite materials is to place the metal parts in the embedded area of ​​the composite material in advance during the composite material molding process, and then mold them together with the composite material. Since the resin and fiber have a certain fluidity during the curing process, this method is prone to causing the position of the metal parts in the molded composite material product to shift, resulting in inaccurate positioning of the metal parts. Summary of the Invention

[0004] The main objective of this invention is to provide a method for accurately embedding metal parts in thick composite materials, thereby solving the problem of inaccurate positioning of internal metal embedded parts when forming thick composite materials on a rotating mold.

[0005] The technical solution adopted in this invention is: A method for precisely embedding metal parts in a thick composite material includes the following steps: S1. Determine the appropriate single-molding thickness of the composite material by using the curing exothermic curve of the composite material and the internal quality of the composite material after molding. S2. Determine the total thickness of the composite precast panel based on the product thickness and the height of the metal embedded parts, and calculate the number of composite precast panels based on the single molding thickness of the composite material. S3. Prepare composite prefabricated panels. The inner surface of the composite prefabricated panels is adapted to the forming surface of the rotary mold. Each composite prefabricated panel consists of two symmetrical panels. S4. Process the corresponding composite material prefabricated panels according to the size and position of the metal embedded parts; S5. Form the inner skin on the surface of the rotating body mold, embed the metal pre-embedded parts into the composite material precast plate, and assemble the adjacent precast plates on the rotating body mold by alternating splicing up and down and left and right, and contact the inner skin. S6. In conjunction with horizontal positioning fixtures, further ensure the positioning accuracy of metal embedded parts; S7. Lay the outer skin of the product on the surface of the composite precast panel, and demold the product from the rotating mold after the product has cured.

[0006] In the above scheme, in S1, firstly, according to the curing exothermic curve, the internal peak temperature is required to be less than the resin degradation safety threshold temperature; secondly, non-destructive testing is used to confirm whether there is delamination and porosity inside. If there is no delamination and the porosity is qualified, then the corresponding thickness is the maximum single molding thickness of the composite material.

[0007] In the above scheme, in S3, the preparation process of each composite material prefabricated panel adopts the method of laying prepreg and hot autoclave molding.

[0008] In the above scheme, in S4, holes that are compatible with the metal embedded parts are machined at the corresponding positions of each composite material prefabricated plate, and a single-sided assembly gap of 0.2mm to 1mm is reserved.

[0009] In the above scheme, in S5, before embedding the metal part, the surface of the metal embedded part is first ground and cleaned with acetone or alcohol to ensure that the surface of the metal embedded part is clean and free of oil; then the metal embedded part is evenly covered with adhesive, and the thickness of the adhesive is between 0.1mm and 0.3mm.

[0010] In the above scheme, after all the composite prefabricated panels are assembled onto the rotating mold, a force parallel to the axis of the rotating mold is uniformly applied to the end composite prefabricated panels to remove the glue overflowing from the edges.

[0011] In the above scheme, in S6, a horizontal positioning fixture is used to correct the horizontal position of the composite material precast plate and the end face of the rotating mold, thereby improving the positioning accuracy of the metal embedded parts.

[0012] Accordingly, the present invention also proposes a thick composite material containing metal embedded parts, which is prepared by the above-mentioned method of precisely embedding metal parts in the thick composite material.

[0013] The beneficial effects of this invention are: This invention divides thick composite materials into multiple prefabricated composite panels. Metal embedded parts can be precisely positioned using machining holes in the prefabricated panels and horizontal positioning fixtures, solving the problem of inaccurate positioning of embedded parts when preparing thick composite materials on a rotating mold. The alternating assembly of the prefabricated composite panels not only effectively improves the strength at the joints but also fixes the assembly position using metal embedded parts, minimizing the assembly gap between the prefabricated panels and the rotating mold, further improving the positioning accuracy of the metal embedded parts. In this method, the connection between the metal embedded parts and the composite material product is more stable, the positioning accuracy is controllable, and the risk of embedded parts detachment can be avoided. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram showing the relative positions of three precast composite material slabs and metal embedded parts in an embodiment of the present invention; wherein, (1-1) is the front view, (1-2) is the side view, and (1-3) is the sectional view along the AA direction; Figure 2 This is a schematic diagram of the structure of the rotating mold in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the first composite material precast panel in the embodiment of the present invention; wherein, (3-1) is the front view, (3-2) is the sectional view along the AA direction, and (3-3) is the enlarged view at point C; Figure 4 This is a schematic diagram of the structure of the second composite material prefabricated plate in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the third composite material prefabricated plate in an embodiment of the present invention; Figure 6 This is a schematic diagram of the assembly of three composite material prefabricated panels on a rotating mold in an embodiment of the present invention; wherein, (6-1) is a schematic diagram of the first composite material prefabricated panel being assembled from left to right, (6-2) is a schematic diagram of the second composite material prefabricated panel being assembled from top to bottom, and (6-3) is a schematic diagram of the third composite material prefabricated panel being assembled from left to right.

[0016] In the figure: 1. First composite material precast panel; 2. Second composite material precast panel; 3. Third composite material precast panel; 4. Metal embedded part; 5. Rotary mold. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] It should be noted that the illustrations provided in the embodiments of the present invention are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0019] In this invention, it should also be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used only for descriptive and distinguishing purposes and should not be construed as indicating or implying relative importance.

[0020] In this embodiment, the rotating mold 5 is a cylindrical mold. A method for accurately embedding metal parts in a thick composite material includes the following steps: S1. Determine the appropriate single-molding thickness of the composite material by using the curing exothermic curve of the composite material and the internal quality of the composite material after molding.

[0021] Specifically, during the curing verification of composite material samples of different thicknesses, thermocouples were used to monitor the temperature in real time during the curing process, and curing exothermic curves of samples of different thicknesses were obtained. First, the internal peak temperature was required to be lower than the resin degradation safety threshold temperature. Second, non-destructive testing was used to confirm whether there was delamination and porosity inside. If there was no delamination and the porosity was qualified, the corresponding thickness was the maximum single molding thickness of the composite material.

[0022] S2. Determine the total thickness of the composite material precast panel based on the product thickness and the height of the metal embedded part 4, and calculate the number of composite material precast panels based on the single molding thickness of the composite material.

[0023] In this embodiment, the number of composite material prefabricated panels is 3, such as Figure 1 As shown, it includes a first composite material precast slab 1, a second composite material precast slab 2, and a third composite material precast slab 3, with eight metal embedded parts 4 evenly arranged along the circumference of the three precast slabs.

[0024] S3. Prepare composite material prefabricated panels. The inner surface of the composite material prefabricated panels is adapted to the forming surface of the rotary mold 5. Each composite material prefabricated panel consists of two symmetrical panels.

[0025] In this embodiment, prepreg is laid and autoclaved to prepare a first composite material precast panel 1, a second composite material precast panel 2, and a third composite material precast panel 3. The thickness of each panel is less than the maximum molding thickness, and each precast panel consists of two symmetrical panels.

[0026] Because the inner skin molding surface is uneven, the reserved assembly gap is insufficient for the annular composite prefabricated panel to pass through the surface protrusion area (which may be 1-2mm) for positioning and bonding. Therefore, it can only be spliced ​​in sections. Considering the practicality of the process, the three composite prefabricated panels are all made into two symmetrical pieces for splicing.

[0027] Steps S1-S3 solve the problem that resin is prone to rapid polymerization during the molding of thick composite materials, which affects the accuracy of the metal embedded parts 4.

[0028] S4. Process the corresponding composite material prefabricated panels according to the size and position of the metal embedded parts 4.

[0029] Common three-axis and five-axis machining has a size limitation of 2m*1m. Machining products larger than 2m*1m places higher demands on the machining site and equipment. This invention solves the problem of machining site and equipment limitations for large-sized products by machining mounting holes for metal embedded parts 4 on composite precast plates.

[0030] In this embodiment, holes are machined at corresponding positions on the three composite precast panels according to the shape and size of the metal embedded part 4, with a single-sided assembly gap of 0.2mm to 1mm reserved. The three processed composite precast panels are as follows: Figure 3-5 As shown.

[0031] S5. The inner skin is formed on the surface of the rotary mold 5. The metal embedded part 4 is embedded in the composite material precast plate. The precast plates are assembled on the rotary mold 5 by alternating splicing between the upper and lower and left and right sides, and contact the inner skin.

[0032] In this embodiment, the surface of the metal embedded part 4 is polished and cleaned with acetone or alcohol to ensure that the surface of the metal embedded part is clean and free of oil stains. Then, epoxy adhesive is used to evenly cover the metal embedded part 4, with the adhesive thickness between 0.1mm and 0.3mm.

[0033] The large ends of the metal embedded part 4 are inserted into the machining holes in the first composite material precast plate 1. An epoxy film is applied to the bonding interface between the first composite material precast plate 1 and the second composite material precast plate 2. The two plates of the first composite material precast plate 1 are assembled on the rotating mold 5 in a left-right fitting manner, and the two plates of the second composite material precast plate 2 are assembled on the mold in an up-down fitting manner. Next, an epoxy film is applied to the bonding interface between the second composite material precast plate 2 and the third composite material precast plate 3, and the small ends of the metal embedded part 4 are inserted into the third composite material precast plate 3. The two plates of the third composite material precast plate 3 are assembled on the mold in a left-right fitting manner.

[0034] The three precast composite material panels are spliced ​​together alternately, one above the other and one to the left and right (e.g.) Figure 6As shown, the precast panels are assembled on the mold, which solves the strength problem at the joints of the precast panels. In addition, the composite precast panels 1, 2, and 3, which are assembled on the rotating mold 5 in an alternating up-down and left-right manner, can be fixed in position by the metal embedded parts 4, minimizing the assembly gap between the precast panels and the rotating mold 5, and further improving the positioning accuracy of the metal embedded parts 4.

[0035] Finally, a force parallel to the axis of the rotating mold 5 is uniformly applied to the third composite material precast plate 3 to remove the glue overflowing from the edges.

[0036] S6. In conjunction with the horizontal positioning fixture, further ensure the positioning accuracy of the metal embedded part 4.

[0037] By using a horizontal positioning fixture, the horizontal positions of the composite material precast plate and the end face of the rotary mold 5 are corrected to make them parallel, thereby improving the positioning accuracy of the metal embedded part 4.

[0038] In this embodiment, the horizontal positioning fixture is placed on the reference surface of the end face of the rotating mold 5, and the horizontal beam of the horizontal positioning fixture is adjusted to be horizontal using a level. The composite precast plate is then finely adjusted to match the calibration surface of the horizontal positioning fixture to ensure uniform contact and tight fit.

[0039] After the adhesive has cured, the surface should be trimmed.

[0040] S7. Lay the outer skin of the product on the surface of the composite precast panel.

[0041] In this embodiment, a composite material outer skin is finally laid on the surface of the three composite material prefabricated panels, and the whole is co-cured with the product body. Finally, the product is demolded from the rotating mold 5.

[0042] The method for precisely embedding metal parts in thick composite materials proposed in this invention solves the problem of embedding metal parts in thick composite materials, and enables the metal embedded part 4 to be precisely positioned through the machined holes of the composite prefabricated plates 1, 2, and 3. The composite prefabricated plates 1, 2, and 3, which are assembled on the rotary mold 5 in an alternating up-down and left-right manner, can also have their assembly positions fixed by the metal embedded part 4, minimizing the assembly gap between the prefabricated plates and the rotary mold 5, and further improving the positioning accuracy of the metal embedded part 4. In this way, the connection between the metal embedded part 4 and the composite product is more stable, the positioning accuracy is controllable, and the risk of the embedded part being pulled out can be avoided.

[0043] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0044] The order of the steps in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0045] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for precision embedding of metal parts in large thickness composites, characterized in that, The method comprises the following steps: S1, determining the single forming thickness of the composite material by the curing exothermic curve of the composite material and the internal quality of the composite material after forming; S2, determining the total thickness of the composite material prefabricated plate according to the product thickness and the height of the metal embedded part, and calculating the number of the composite material prefabricated plates in combination with the single forming thickness of the composite material; S3, preparing the composite material prefabricated plates, the inner surface of each composite material prefabricated plate is matched with the forming surface of the rotary body mold, and each composite material prefabricated plate comprises two symmetric plates; S4, processing the corresponding composite material prefabricated plates according to the size and position of the metal embedded part; S5, forming the inner skin on the surface of the rotary body mold, embedding the metal embedded part in the composite material prefabricated plate, and assembling the adjacent prefabricated plates on the rotary body mold in an up-down and left-right alternating manner and in contact with the inner skin; S6, further ensuring the positioning accuracy of the metal embedded part in cooperation with the horizontal positioning tooling; S7, laying the outer skin of the product on the surface of the composite material prefabricated plate, and demolding the product from the rotary body mold after curing.

2. The method of claim 1, wherein, In S1, firstly, the internal peak temperature is required to be less than the safety threshold temperature of resin degradation according to the curing exothermic curve; secondly, the nondestructive testing is used to confirm whether there is delamination and porosity in the interior, and if the delamination and porosity are qualified, the corresponding thickness is the maximum single forming thickness of the composite material.

3. The method of claim 1, wherein, In S3, the preparation process of each composite material prefabricated plate adopts the laying and pasting of prepreg and the autoclave forming.

4. The method of claim 1, wherein, In S4, the hole position matched with the metal embedded part is processed at the corresponding position of each composite material prefabricated plate, and the assembly gap on one side is reserved between 0.2mm and 1mm.

5. The method of claim 1, wherein, In S5, before embedding the metal part, the surface of the metal embedded part is polished and cleaned with acetone or alcohol to ensure that the surface of the metal embedded part is clean and free of oil stains; then the metal embedded part is uniformly coated with adhesive, and the thickness of the adhesive is between 0.1mm and 0.3mm.

6. The method of claim 5, wherein, After all the composite material prefabricated plates are assembled on the rotary body mold, a force parallel to the axis of the rotary body mold is uniformly applied to the end composite material prefabricated plates to remove the excess glue at the edges.

7. The method of claim 1, wherein, The specific method of S6 is that the horizontal positioning tooling is placed on the end surface reference surface of the rotary body mold, the horizontal positioning tooling is adjusted to be in a horizontal state by using the level, the composite material prefabricated plate is finely adjusted with the calibration surface of the horizontal positioning tooling to ensure uniform contact and close fit.

8. A large thickness composite material containing a metal insert, characterized in that, The method for precisely embedding metal parts in large-thickness composite materials is prepared by any one of claims 1-7.

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