A process method capable of realizing integrated molding and assembly of composite material bracket

Abstract

The present invention belongs to the technical field of composite material forming, and relates to a process method for the integrated forming and assembly of a composite material bracket. The method comprises: dividing the composite material bracket into an upper mounting plate, a lower mounting plate, and side support pillars, wherein the functional area of ​​the upper mounting plate and the lower mounting plate is a grid structure; forming the grid structure of the upper mounting plate and the lower mounting plate; forming the side support pillars; installing the formed grid structure and side support pillars of the upper mounting plate and the lower mounting plate in an upper plate forming mold and a lower plate forming mold, and performing integrated forming of the upper mounting plate, the lower mounting plate, and the side support pillars. The present invention divides the structure of the composite material bracket, designs suitable tooling molds and forming methods according to the different structural characteristics of the product after dividing, and can improve production efficiency and reduce production costs while ensuring the structural strength of the product.

Description

Technical Field

[0001] The invention relates to a process method for integrating the forming and assembling of a composite material bracket, and belongs to the technical field of composite material forming. Background Art

[0002] Composite materials have excellent mechanical properties, including high specific stiffness and strength, as well as fatigue and corrosion resistance, and are widely used in aviation, aerospace, and other fields. Compared to aluminum alloy brackets, composite brackets of the same structure weigh less, withstand greater loads, and have higher structural efficiency.

[0003] However, due to the specialized functions of composite brackets, their numerous openings and complex structure, using a monolithic molding process would require extensive layering, difficult assembly and demolding, and lengthy production times. To simplify the process and improve production efficiency, a novel integrated molding and assembly process for composite brackets was proposed, enabling rapid prototyping and assembly of multi-layer composite brackets. Summary of the Invention

[0004] The purpose of the present invention is to classify the structure of the composite material bracket, and design suitable tooling molds and molding methods according to the different structural characteristics of the products after classification, so as to ensure the structural strength of the products while improving production efficiency and reducing production costs.

[0005] The technical solution adopted in the present invention is as follows:

[0006] A process for integrating the molding and assembly of a composite material bracket comprises the following steps:

[0007] The composite material bracket is divided into an upper mounting plate, a lower mounting plate and side support pillars, wherein the functional areas of the upper mounting plate and the lower mounting plate are grid structures;

[0008] forming the grille structure of the upper and lower mounting plates;

[0009] molded side support struts;

[0010] The formed grid structures and side support pillars of the upper and lower mounting plates are installed in the upper plate forming mold and the lower plate forming mold to perform integrated molding of the upper and lower mounting plates and the side support pillars.

[0011] Furthermore, the reinforcing fiber used in the composite material bracket is carbon fiber or glass fiber, the upper mounting plate and the lower mounting plate use glass fiber, the side support pillars use carbon fiber, or the upper mounting plate, the lower mounting plate and the side support pillars all use glass fiber or carbon fiber.

[0012] Furthermore, the composite material bracket adopts a resin that is cured at room temperature or low temperature or medium or high temperature, and the resin is epoxy resin, bismaleimide resin, phenolic resin or polyimide resin.

[0013] Furthermore, the side support struts are a solid composite material structure, or a sandwich structure composed of a composite material skin and a weight-reducing core layer.

[0014] Furthermore, the grid structure includes a plane grid formed by the intersection of transverse ribs and longitudinal ribs.

[0015] Furthermore, the forming step of the grid structure includes: forming a long tube by winding or pultrusion process, then cutting it into multiple frames along the length direction of the long tube, and combining the multiple frames by adhesive or high resin content prepreg to form a grid.

[0016] Furthermore, the composite material bracket includes four side support pillars, and the side support pillars include side support pillars with weight-reducing grooves and side support pillars without weight-reducing grooves; the side support pillars with weight-reducing grooves are formed by stacking layers of templates, and the side support pillars without weight-reducing grooves are formed by winding layers on a foam core material.

[0017] Furthermore, the integrated molding of the upper mounting plate, the lower mounting plate and the side support pillars includes: combining the upper mounting plate, the lower mounting plate and the side support pillars with an adhesive, and curing and molding the combined upper mounting plate, the lower mounting plate and the side support pillars.

[0018] Furthermore, the integrated molding of the upper mounting plate, the lower mounting plate and the side support pillars includes:

[0019] Place the cut grille frames into the upper and lower plate forming molds for assembly, bond adjacent frames together, and lay up the upper and lower mounting plates with carbon fiber / epoxy resin prepreg in areas other than the grille. After the lay-up is complete, install the top molds of the upper and lower plate forming molds on the bottom molds, and secure them so that the gap between them is less than 0.10mm.

[0020] Bond the lateral support pillars to the butt joint surfaces of the upper mounting plate and the lower mounting plate, then butt joint the lateral support pillars to the lower plate forming mold, install the assembly tooling guide pillars on the lower plate forming mold, install the upper plate forming mold on the assembly tooling guide pillars, and butt joint the lateral support pillars to the upper plate forming mold;

[0021] The upper plate forming mold and the lower plate forming mold are moved into an oven for curing and molding.

[0022] The present invention also provides a composite material bracket formed according to the method.

[0023] The beneficial effects of the present invention are as follows:

[0024] Through actual production verification, the product production time of the present invention is reduced by nearly 50% compared with the overall molding solution. Due to the significant reduction in labor cost, the production cost of the present invention is reduced by 32.7% compared with the overall molding solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural diagram of the composite material bracket.

[0026] Figure 2 This is a parting diagram of the composite material bracket.

[0027] Figure 3 This is a diagram of the side support pillar molding.

[0028] Figure 4 It is a structural diagram of the bracket assembly combination tooling.

[0029] Figure 5 It is the parting drawing of the bracket assembly tooling. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to specific embodiments and accompanying drawings.

[0031] The present invention first divides the composite material bracket into a functional area and a support area, and then performs a secondary molding of the functional area and the support area. Parts with large thickness and complex layup adopt a solution of pre-forming flat plates and then machining. Parts with the same dimensional characteristics adopt a process solution of one mold and multiple pieces. The components are finally assembled and combined using high-resin content prepreg or adhesive. The dimensional accuracy and spatial position of each component of the bracket are guaranteed by the forming mold and the assembly combination mold.

[0032] like Figure 1 、 Figure 2 As shown, the composite material bracket 10 can be divided into an upper mounting plate 20 , a lower mounting plate 30 , and side support pillars 40 , 50 , 60 , and 70 .

[0033] The composite material bracket 10 uses carbon fiber or glass fiber as the reinforcing fiber. Depending on the required stiffness, strength index and weight index, and the comprehensive product cost considerations, glass fiber can be used in the upper mounting plate 20 and the lower mounting plate 30, and carbon fiber can be used in the side support pillars 40 to 70, or all of them can be made of glass fiber or carbon fiber.

[0034] The composite material bracket 10 may be made of a resin that cures at room temperature or at medium or high temperature, depending on the usage environment. The resin may be epoxy resin, bismaleimide resin, phenolic resin or polyimide resin.

[0035] The functional areas of the upper mounting plate 20 and the lower mounting plate 30 of the composite material bracket 10 are generally grid structures. The horizontal and vertical ribs of the grid cross to form a planar grid for mounting products and performing the function of the bracket.

[0036] The side support pillars 40 to 70 of the composite material bracket 10 can be a composite material solid structure or a sandwich structure composed of a composite material skin and a weight-reducing core layer, depending on different load-bearing, weight and cost requirements.

[0037] The grid structure of the composite bracket 10, including the upper mounting plate 20 and the lower mounting plate 30, is typically manufactured using the following method: a long tube is formed using a winding or pultrusion process, and then cut into multiple narrow sections along the height direction (the length of the tube). The multiple sections are then assembled using adhesive or high-resin content prepreg to form the grid.

[0038] The composite material bracket 10 comprises an upper mounting plate 20, a lower mounting plate 30, and lateral support struts 40-70 assembled using an adhesive that can be cured at room temperature or at medium to high temperatures. The dimensional accuracy of the assembled product is ensured by an assembly tool. The assembly tool can achieve integrated bonding and curing of the upper and lower mounting plates and lateral support struts, or it can be combined by bonding and curing the upper and lower mounting plates separately before bonding them to the lateral support struts.

[0039] In one embodiment of the present invention, forming a composite material bracket product includes the following steps:

[0040] The composite material bracket is divided into an upper mounting plate, a lower mounting plate and side support pillars, wherein the functional areas of the upper mounting plate and the lower mounting plate are grid structures;

[0041] forming the grille structure of the upper and lower mounting plates;

[0042] molded side support struts;

[0043] The formed grid structures and side support pillars of the upper and lower mounting plates are installed in the upper plate forming mold and the lower plate forming mold to perform integrated molding of the upper and lower mounting plates and the side support pillars.

[0044] In one embodiment of the present invention, the grid structure of the molded upper mounting plate and the lower mounting plate comprises:

[0045] Place the carbon fiber / epoxy resin prepreg onto the automatic winding and slitting platform for slitting;

[0046] Clean the grid winding mold and apply the release agent. After the release agent turns into a uniform and transparent film, hoist the winding mold onto the auxiliary device of the winding machine.

[0047] The die end face is used as the winding starting point, and the winding end position is determined according to the starting position and winding length. The winding parameters are set, including winding length, number of winding layers, whether to stop between layers, winding radius, winding tension, yarn width, etc.

[0048] Debug the winding machine and return it to the origin. Pass the carbon fiber / epoxy resin prepreg tape through the guide roller. Call up the program, enter the starting and ending positions, and start the winding program.

[0049] Heat the prepreg tape, wind it according to the procedure, and cut the prepreg tape after completing one cycle;

[0050] The wrapped prepreg tape is packaged with a non-porous film, breathable felt and vacuum bag in sequence, sealed with sealing strips and vacuumed, and finally pushed into an autoclave for curing;

[0051] The solidified product is cut on a machine tool into square frames.

[0052] In one embodiment of the present invention, the molded side support pillar comprises:

[0053] Each composite material bracket includes four side support pillars, which include side support pillars with weight-reducing grooves and side support pillars without weight-reducing grooves; the side support pillars with weight-reducing grooves are formed by stacking layers of templates, and the side support pillars without weight-reducing grooves are formed by wrapping layers on foam core materials.

[0054] In one embodiment of the present invention, the integrated molding of the upper mounting plate, the lower mounting plate and the side support pillars includes: combining the upper mounting plate, the lower mounting plate and the side support pillars with an adhesive, and curing and molding the combined upper mounting plate, the lower mounting plate and the side support pillars.

[0055] In one embodiment of the present invention, the integrated molding of the upper mounting plate, the lower mounting plate, and the side support pillars includes:

[0056] Place the cut grille frames into the upper and lower plate forming molds for assembly, bond adjacent frames together, and lay up the upper and lower mounting plates with carbon fiber / epoxy resin prepreg in areas other than the grille. After the lay-up is complete, install the top molds of the upper and lower plate forming molds on the bottom molds, and secure them so that the gap between them is less than 0.10mm.

[0057] Bond the lateral support pillars to the butt joint surfaces of the upper mounting plate and the lower mounting plate, then butt joint the lateral support pillars to the lower plate forming mold, install the assembly tooling guide pillars on the lower plate forming mold, install the upper plate forming mold on the assembly tooling guide pillars, and butt joint the lateral support pillars to the upper plate forming mold;

[0058] The upper plate forming mold and the lower plate forming mold are moved into an oven for curing and molding.

[0059] In one embodiment of the present invention, a complete process for forming a composite material bracket product is provided, including the following steps:

[0060] The first step is to install the upper and lower panels to form the grid structure.

[0061] Place the T700 grade carbon fiber / 9368 epoxy resin prepreg on the automatic slitting platform for winding. Set the width to 110mm, the wide band coefficient to 0.125, the automatic speed to 1000, the manual speed to 800, and then slitting.

[0062] Clean the grid winding mold and apply Ken-Tian 255 release agent. After the release agent becomes a uniform and transparent film, hoist the winding mold onto the auxiliary device of the winding machine.

[0063] The die end face is used as the winding starting point, and the winding end position is determined by the starting position and winding length. Winding length is approximately 400mm; number of winding layers: 1; whether to pause between layers (0 / 1): 1; winding radius (mm): 850; winding tension (N): 180; yarn sheet width (mm): 1.4.

[0064] Debug the winding machine back to the origin, pass the 110mm wide T700 grade carbon fiber / 9368 epoxy resin prepreg tape through the guide roller, call up the program, enter the starting and end positions, and start the winding program.

[0065] Start the hot roller at the wire nozzle to heat the prepreg tape, and the heating temperature is controlled at 90-110℃; wind it according to the procedure, and cut the prepreg tape after completing one cycle.

[0066] The wrapped prepreg tape is then packaged with a non-porous membrane, breathable felt, and vacuum bag, sealed with sealing tape, and then vacuumed. Finally, the product is placed in an autoclave for curing. The curing parameters are as follows: room temperature → start heating (constant temperature 90°C, start pressurization) → 100°C ± 10°C → pressurize to 0.5MPa → heat (constant temperature 130°C) → 120°C ± 10°C → pressurize to 0.8MPa, hold for 2 hours, turn off heating, slowly release pressure → cool to below 50°C (cooling rate should be less than 2°C / min), and then remove from the autoclave.

[0067] The solidified product is cut on a machine tool into two sizes of square frames with heights of 15 mm and 30 mm. The two sizes of square frames are used to form the upper mounting plate and the lower mounting plate respectively.

[0068] The second step is to form the side support pillars.

[0069] Each bracket has four pillars on the side to realize structural bearing. The pillars have two structures, one with weight-reducing grooves and the other without weight-reducing grooves.

[0070] Use an automatic cloth cutting machine to cut the pillar templates and lay the cut pillar templates in the mold in order, such as Figure 3 As shown, the side support pillar forming mold consists of a top mold 101 and a bottom mold 102. The side support pillars are 103. The pillars with weight-reducing grooves are laminated using a template, while the pillars without weight-reducing grooves are laminated using a wrapping method around a foam core.

[0071] After the product layup is complete, move the mold into the press and place a 2mm gasket between the top and bottom molds. Set the press temperature to 110°C. When the mold temperature reaches 90°C, apply pressure of 3MPa-5MPa. Wait for 3 minutes and then continue pressurizing until the gap between the top and bottom molds is less than 0.10mm. Set the press temperature to 140°C, heat the mold to (130±5)°C, hold for 120 minutes, and then naturally cool it down to below 50°C.

[0072] The third step is to bond the upper and lower mounting plates and assemble the upper and lower mounting plates and the side support pillars into an integrated unit.

[0073] like Figure 4 、 Figure 5As shown, the grid frames cut in the first step are placed into upper and lower plate molds (including upper plate forming mold 201 and lower plate forming mold 202) for assembly. A layer of J-47B glue is evenly brushed on the mating surfaces of adjacent frames. After airing for (20-30) minutes, a layer of J-47A glue mold is applied. T700-grade carbon fiber / 9368 medium-temperature epoxy resin prepreg is used to lay up the other areas of the upper and lower mounting plates except the grid. After the layup is completed, the top molds of the upper and lower plate forming molds are respectively installed on the bottom molds, that is, the top mold 2011 of the upper plate forming mold 201 is installed on the bottom mold 2012, and the top mold 2021 of the lower plate forming mold 202 is installed on the bottom mold 2022. The top and bottom molds are tightened with screws to ensure that the gap between the top and bottom molds is less than 0.10mm.

[0074] Apply a uniform layer of J-47B glue to the mating surfaces of the lateral support struts 203 and the upper and lower mounting plates. After allowing to air for 20-30 minutes, apply a layer of J-47A glue mold. Then, align the lateral support struts 203 with the installed lower plate forming mold 202. Install the assembly tooling guide posts 204 on the lower plate forming mold. Finally, install the upper plate forming mold on the assembly tooling guide posts 204. Align the lateral support struts 203 with the upper plate forming mold 201, completing the assembly of the product and the bracket assembly tooling.

[0075] Move the mold into the oven and set the oven temperature to 175℃. When the mold temperature rises to 130℃±5℃, set the oven temperature to 145℃ and keep it warm for 2h. Then cool the mold naturally to below 50℃ for demoulding to complete product curing.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process method for realizing integrated molding and assembly of composite material brackets, characterized in that: The following steps are involved: The composite material bracket is divided into an upper mounting plate, a lower mounting plate and side support pillars, wherein the functional areas of the upper mounting plate and the lower mounting plate are grid structures; forming the grille structure of the upper and lower mounting plates; molded side support struts; The formed grille structures and side support pillars of the upper and lower mounting plates are installed in the upper plate forming mold and the lower plate forming mold to perform integrated molding of the upper mounting plate, the lower mounting plate and the side support pillars; The steps of forming the grid structure include: forming a long tube by winding or pultrusion, cutting the long tube into a plurality of square frames along the length direction, and combining the plurality of square frames by adhesive or high resin content prepreg to form a grid; The integrated molding of the upper mounting plate, the lower mounting plate and the side support pillars includes: Place the cut grille frames into the upper and lower plate forming molds for assembly, bond adjacent frames together, and lay up the upper and lower mounting plates with carbon fiber / epoxy resin prepreg in areas other than the grille. After the lay-up is complete, install the top molds of the upper and lower plate forming molds on the bottom molds, and secure them so that the gap between them is less than 0.10mm. Bond the lateral support pillars to the butt joint surfaces of the upper mounting plate and the lower mounting plate, then butt joint the lateral support pillars to the lower plate forming mold, install the assembly tooling guide pillars on the lower plate forming mold, install the upper plate forming mold on the assembly tooling guide pillars, and butt joint the lateral support pillars to the upper plate forming mold; The upper plate forming mold and the lower plate forming mold are moved into an oven for curing and molding.

2. The method according to claim 1, characterized in that The reinforcing fiber used in the composite material bracket is carbon fiber or glass fiber, the upper mounting plate and the lower mounting plate use glass fiber, and the side support pillars use carbon fiber, or the upper mounting plate, the lower mounting plate and the side support pillars all use glass fiber or carbon fiber.

3. The method according to claim 1, characterized in that The composite material bracket adopts a resin that is cured at room temperature or low temperature or medium or high temperature, and the resin is epoxy resin, bismaleimide resin, phenolic resin or polyimide resin.

4. The method according to claim 1, wherein The side support struts are a composite solid structure, or a sandwich structure composed of a composite skin and a weight-reducing core layer.

5. The method according to claim 1, wherein The grid structure includes a plane grid formed by the intersection of transverse ribs and longitudinal ribs.

6. The method according to claim 1, characterized in that The composite material bracket includes four side support pillars, and the side support pillars include side support pillars with weight-reducing grooves and side support pillars without weight-reducing grooves; the side support pillars with weight-reducing grooves are formed by a template stacking and lamination method, and the side support pillars without weight-reducing grooves are formed by a winding and lamination method on a foam core material.

7. The method according to claim 1, characterized in that The integrated molding of the upper mounting plate, the lower mounting plate and the side support pillars includes: combining the upper mounting plate, the lower mounting plate and the side support pillars by means of an adhesive, and curing and molding the combined upper mounting plate, the lower mounting plate and the side support pillars.

8. A composite material stent formed according to the method of any one of claims 1 to 7.

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