A mask forming die with an external diaphragm structure and a preparation method

Abstract

The application discloses a forming die with an outer diaphragm structure light shield cover and a preparation method, and belongs to the technical field of composite material preparation. The forming die comprises a die upper cover, a plurality of diaphragm die segments, a cylindrical core die and a die base. The cylindrical core die is in a cylindrical shape. The plurality of diaphragm die segments are seven layers in total and are conical in shape. Each layer is broken into four segments. A demolding angle is designed at the segment connection. Threaded holes are arranged on each segment. The preparation method comprises the following steps: preparation before laying, brushing of carbon cloth or silk cloth, ring winding, prepreg laying, bag making, autoclave curing and demolding. Foam and demolding cloth are used to make a few-shaped structure beam to enhance the flange strength of the product during demolding. The application firstly proposes the design of the die with the outer diaphragm structure light shield cover, which can ensure the layer angle and continuity during the forming process and ensure that the prepared outer diaphragm structure light shield cover is stable in performance and accurate in size.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation technology, and in particular relates to a molding die and preparation method for a light shield with an external aperture structure. Background Technology

[0002] Composite materials are multiphase solid materials composed of two or more substances with different physical and chemical properties. They retain the main characteristics of the original constituent materials, and through material design, the properties of each component can complement and interact with each other, thereby achieving new superior properties. Generally, composite materials that can be used in primary and secondary load-bearing structures, with stiffness and strength equivalent to or exceeding that of aluminum alloys, are called advanced composite materials. Carbon fiber reinforced resin matrix composites are currently the most widely used advanced composite materials. In the aerospace field, lightweight yet strong materials are crucial for aircraft and spacecraft. As the mass of an aircraft or spacecraft increases, a higher-powered engine is required, leading to increased engine and fuel mass, as well as larger fuel storage devices. These changes in mass trigger a series of chain reactions. Using composite materials with high specific strength and specific modulus in aircraft and spacecraft can significantly reduce mass, conserve energy and materials, and substantially lower costs.

[0003] Currently, traditional light shields are typically cylindrical or cylindrical with a few tapered sections, and the molding and fabrication methods for this type of light shield are relatively mature. However, there is no known method for molding and fabricating a light shield with an alternating I-shaped cross-section for an external aperture structure. For this type of irregularly shaped light shield, there is currently no good technical solution. Traditional light shields, whether cylindrical or tapered, are linear structures, and their mold cores are smooth cylinders or frustums, making it relatively easy to ensure the layup angle and continuity. In contrast, the tapered section of an external aperture structure light shield is an unconventional linear structure with an alternating I-shaped cross-section, requiring the design of a reasonable mold and layup method to ensure the layup angle and continuity. Summary of the Invention

[0004] In view of this, in order to solve the technical problems mentioned in the background art, the present invention proposes a molding die and preparation method for a light shield with an outer aperture structure. It is a multi-segmented lobed mold and a material laying method to ensure the layup angle and continuity of this type of product during the molding process. The method can ensure the performance and dimensional stability of the prepared light shield with an outer aperture structure, and meet the design and use requirements.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a mold for forming a light shield with an external aperture structure, comprising a mold top cover, a multi-layer aperture mold segment structure, a cylindrical core mold and a mold base, wherein the multi-layer aperture mold segment structure is connected to the cylindrical core mold, the mold top cover is installed on the top of the multi-layer aperture mold segment structure, and the mold base is installed on the bottom of the cylindrical core mold; The cylindrical core mold is cylindrical, and the multi-layer aperture mold has multiple layers of segmented structure. The overall shape is conical, and each layer is divided into at least two segments. The segment connection is designed with a demolding angle, which includes a positive demolding angle and a negative demolding angle.

[0006] Preferably, each segment of the multi-layer aperture mold segment structure is provided with a threaded hole, which serves as both a connection hole with the core mold during the laying process and a demolding hole for pulling out the mold segment when the product is demolded.

[0007] Preferably, the multi-layer aperture mold has seven layers, and each layer is divided into four lobes.

[0008] Preferably, during demolding, the mold segment with the positive demolding angle is demolded first, followed by the mold segment with the negative demolding angle.

[0009] Preferably, the mold cover is locked to the top of the multi-layer aperture mold segment structure to ensure the mold closing accuracy in the layup height direction.

[0010] A method for preparing a light shield with an external aperture structure, using the above-mentioned molding mold, specifically includes the following steps: Step 1: Preparation before laying: Make specific cutting templates for the upper and lower flanges of the light shield and the outer aperture structure, and cut the material according to the size and layup angle of each layer of the outer aperture structure; use putty and high temperature tape to fill the R-angle on the circumference of the connection between the cylindrical core mold and the mold base, and on the upper and lower circumference of the multi-layer aperture mold segment structure at the position of the outer aperture structure. The second step: The product molding process includes assembling the mold, applying carbon cloth or silk cloth, wrapping the ring reinforcement, laying the prepreg, making the bag, curing, and demolding. During demolding, the product is inverted, and a Z-shaped structural beam is made around the barrel using foam and demolding cloth. The demolding cloth is soaked in a specific adhesive and laid on the foam. The bottom of the structural beam is connected to the lower flange of the product. After the adhesive cures, it can provide support for the product flange, enhance the strength of the product flange, and prevent the flange from breaking.

[0011] Preferably, the second step of the product forming process specifically includes: S1. Assemble the mold, prepare the required template prepreg according to the blanking template, and fill in the R-corner positions on the mold; S2. Apply a layer of carbon cloth or silk cloth to the connection position between the end of the light shield column and the cone section, and evenly lay the carbon cloth or silk cloth coated with adhesive in the annular groove. S3, loop winding: use yarn to wind in the loop groove, and maintain tension during the winding process to ensure that the fibers do not buckle; S4. Laying: Use prepreg to lay the main body of the sunshade, ensuring symmetrical layup. Use the designed template prepreg for laying the flange surface and the outer aperture. S5. Bag making: Make vacuum bags by sealing the laid prepreg together with the mold. S6. Curing: Use an autoclave for pressure curing; S7. Demolding: Invert the product and remove the core mold from the top of the product. Use foam and release cloth to make a Z-shaped structural beam around the barrel. Soak the release cloth with glue and lay it on the foam. Connect the bottom of the structural beam to the lower flange of the product. Demold after the glue has cured.

[0012] Preferably, in step S3, the theoretical number of winding turns is calculated based on the width and thickness of the girders.

[0013] Preferably, in step S7, the zigzag structural beams are arranged in eight locations on the circumference, evenly distributed around the product barrel.

[0014] Preferably, in step S7, the adhesive is an epoxy resin adhesive or a cyanate ester resin adhesive. After the release cloth is soaked in the adhesive, it is laid on the foam beam and a rigid support structure is formed after the adhesive cures. The prepreg is a carbon fiber reinforced resin-based prepreg, and the resin is any one of cyanate ester resin, epoxy resin, bismaleimide resin, polyimide resin, or phthalic acid cyanide resin.

[0015] Compared with the prior art, the beneficial effects of the mold and preparation method for the light shield with an external aperture structure described in this invention are: 1. This invention is the first to propose a mold design for a light shield with an external aperture structure. By using a multi-layered segmented structure in conjunction with a cylindrical core mold, it can effectively ensure the accuracy and continuity of the layup angle of the irregular cross-section (alternating I-shaped) light shield during the molding process, and successfully produce high-quality light shield products with an external aperture structure.

[0016] 2. The segmented connection of this invention is designed with two demolding angles: positive and negative. During demolding, the positive segment is demolded first, followed by the negative segment. The demolding sequence is reasonable, the operation is simple, and it can effectively avoid damage to the product during the demolding process. The threaded hole on each segment serves both as a connection and demolding function, making it multi-purpose and compact in structure.

[0017] 3. Traditional demolding methods apply demolding force to the product flange, posing a significant risk of breakage or tearing. This invention proposes a novel demolding method: a release cloth is soaked in adhesive and laid on a foam beam. After the adhesive cures, it forms a Z-shaped beam structure, which greatly enhances the strength of the product flange, protects it, prevents breakage, and facilitates smooth demolding.

[0018] 4. This invention effectively solves the problems of layer angle deviation and suspension during the laying of prepreg material for the outer aperture structure light shield by making specific blanking templates and combining them with the R-angle compensation process, thus ensuring the uniformity of product wall thickness and dimensional accuracy. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure of the light shield forming mold described in this invention; Figure 2 This is a schematic diagram of the light shield of the external aperture structure described in this invention; Figure 3 This is a perspective view of the light shield of the external aperture structure described in this invention; Figure 4 A schematic diagram of the segmented structure and demolding sequence of a multi-layer aperture mold; Figure 5 for Figure 4 AA section view; In the diagram: 1-Mold top cover, 2-Multi-layer aperture mold segmented structure, 3-Cylindrical core mold, 4-Mold base, 5-Columnar section, 6-Conical section, 7-Threaded hole. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the drawings, and not all of them. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the invention.

[0021] The light shield described in this invention is divided into two parts: a columnar section 5 and a conical section 6. Both the upper and lower ends of the light shield have flanges. The conical section 6 has an unconventional linear structure, which is an external aperture structure with alternating I-shaped cross-sections. Traditional light shields, whether at the columnar end or the conical section, are linear structures, and their mold cores are smooth cylinders or frustums, making it relatively easy to ensure the layup angle and continuity. However, for the external aperture structure light shield required by this invention, a reasonable mold design and layup method during the molding process are needed to ensure the layup angle and continuity, successfully producing a high-quality product.

[0022] For a specific embodiment 1, see [link / description]. Figure 1-5 This embodiment describes a mold for forming a light shield with an external aperture structure, comprising: a mold top cover 1, a multi-layer aperture mold segment structure 2, a cylindrical core mold 3, and a mold base 4. The multi-layer aperture mold segment structure 2 is connected to the cylindrical core mold 3, the mold top cover 1 is installed on the top of the multi-layer aperture mold segment structure 2, and the mold base 4 is installed on the bottom of the cylindrical core mold 3.

[0023] The cylindrical core mold 3 is cylindrical, and the multi-layer aperture mold segmented structure 2 has seven layers, with an overall conical shape, a small top diameter, and a large bottom diameter. The segmentation is designed according to the product dimensions, with each layer divided into four segments. Demolding angles are designed at the segment connections, with two types: positive and negative. During demolding, the segments with the positive demolding angle should be demolded first, followed by those with the negative demolding angle. The positive demolding angle facilitates smooth sliding of the mold segments along the demolding direction, while the negative demolding angle prevents interference between adjacent segments during demolding.

[0024] Each segment of the multi-layer aperture mold segment structure 2 is provided with a threaded hole 7, which can be used as a connection hole with the core mold during the laying process, and also as a demolding hole for pulling out the mold segment when the product is demolded. During the laying process, the segment is fastened to the core mold by screws passing through the threaded holes 7; during the demolding process, a demolding tool is installed using the threaded holes 7, and a demolding force is applied to pull out the segment layer by layer.

[0025] A method for preparing a light shield with an external aperture structure specifically includes the following steps: Step 1: Preparation before laying The light shield has upper and lower flanges, and the outer aperture structure has many layers. When the prepreg is laid in large sheets, the layup angle is prone to change significantly. Specific cutting templates need to be made for the upper and lower flanges and the outer aperture structure for cutting and laying. The cutting should be carried out according to the size and layup angle of each layer of the outer aperture structure.

[0026] Specifically, the blanking template is made according to the actual unfolded dimensions of each layer of the outer aperture structure, and the layup angle deviation is controlled within ±2° during unfolding. Before laying, putty and high-temperature tape are used to fill the circumference of the connection between the cylindrical core mold 3 and the mold base 4 to create a radius corner. At the same time, radius corners are filled on the upper and lower circumferences of the multi-layer aperture mold segment structure 2 at the position of the outer aperture structure to avoid the phenomenon of suspension and ensure that the prepreg adheres tightly to the mold surface.

[0027] Step 2: Product Forming Process S1. Assemble the mold, prepare the required template prepreg according to the blanking template, and fill in the R-corner positions on the mold to ensure that there are no gaps at the R-corner.

[0028] S2. Apply a layer of carbon fiber or silk cloth to the connection point between the column end 5 and the cone section 6 of the light shield, and evenly lay the carbon fiber or silk cloth coated with adhesive in the annular groove, ensuring that there are no air bubbles or wrinkles in the annular groove.

[0029] S3. Loop winding: Loop winding is performed using a winding machine. Yarn is wound in the loop groove. During the winding process, tension must be maintained to ensure that the fibers do not buckle. The theoretical number of winding turns can be calculated based on the width and thickness of the loop.

[0030] S4. Laying: Lay the main body of the sunshade using prepreg. During the laying process, ensure symmetrical layering and design the layer ratio in each direction according to actual usage requirements. The layering can be designed based on factors such as product thickness, usage conditions, load-bearing stiffness and strength requirements, and prepreg thickness. For flange faces and outer apertures, the designed template prepreg should be used for laying to ensure accurate layering angles at flange faces and outer apertures.

[0031] S5. Bag making: Make vacuum bags according to design requirements, seal the laid prepreg together with the mold to ensure that the vacuum bag has no air leakage.

[0032] S6. Curing: Use an autoclave for pressure curing. The curing temperature, pressure and time are determined according to the resin system used.

[0033] S7. Demolding: During demolding, the product is inverted, with the conical section at the bottom and the column end at the top. The core mold is then removed from the top of the product using conventional demolding methods. Due to the risk of breakage of the lower flange, a Z-shaped structural beam is constructed around the barrel using foam and release cloth. The release cloth is soaked in a specific adhesive and laid on the foam. The bottom of the structural beam is connected to the lower flange of the product. After the adhesive cures, the structural beam provides support for the flange, enhancing its strength. In this implementation case, there are eight demolding points around the product's circumference, therefore eight Z-shaped structural beams are constructed, evenly distributed around the circumference, which increases the strength of the bottom flange, prevents flange breakage, and ensures successful demolding.

[0034] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A molding die for a light shield with an outer aperture structure, characterized in that: The mold includes a mold top cover (1), a multi-layer aperture mold segment structure (2), a cylindrical core mold (3), and a mold base (4). The multi-layer aperture mold segment structure (2) is connected to the cylindrical core mold (3). The mold top cover (1) is installed on the top of the multi-layer aperture mold segment structure (2), and the mold base (4) is installed on the bottom of the cylindrical core mold (3). The cylindrical core mold (3) is cylindrical, and the multi-layer aperture mold segmented structure (2) has multiple layers and is cone-shaped as a whole. Each layer is segmented into at least two segments, and a demolding angle is designed at the segment connection. The demolding angle includes the positive demolding angle and the negative demolding angle.

2. The molding die for a light shield with an outer aperture structure according to claim 1, characterized in that: Each layer of the multi-layer aperture mold segment structure (2) is provided with a threaded hole (7). The threaded hole (7) serves as both a connection hole with the core mold during the laying process and a demolding hole for pulling out the mold segment when the product is demolded.

3. The molding die for a light shield with an outer aperture structure according to claim 1, characterized in that: The multi-layer aperture mold segmented structure (2) has seven layers, and each layer is segmented into four segments.

4. The molding die for a light shield with an outer aperture structure according to claim 1, characterized in that: When demolding, first demold the mold segments with the positive demolding angle, and then demold the mold segments with the negative demolding angle.

5. The molding die for a light shield with an outer aperture structure according to claim 1, characterized in that: The mold cover (1) is locked to the top of the multi-layer aperture mold segment structure (2) to ensure the mold closing accuracy in the layup height direction.

6. A method for preparing a light shield with an outer aperture structure, using a molding die as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Preparation before laying: Make specific blanking templates for the upper and lower flanges of the light shield and the outer aperture structure, and cut the material according to the size and layup angle of each layer of the outer aperture structure; use putty and high temperature tape to fill the R angle on the circumference of the connection between the cylindrical core mold (3) and the mold base (4) and on the circumference of the multi-layer aperture mold segment structure (2) at the position of the outer aperture structure. The second step: The product molding process includes assembling the mold, applying carbon cloth or silk cloth, wrapping the ring reinforcement, laying the prepreg, making the bag, curing, and demolding. During demolding, the product is inverted, and a Z-shaped structural beam is made around the barrel using foam and demolding cloth. The demolding cloth is soaked in a specific adhesive and laid on the foam. The bottom of the structural beam is connected to the lower flange of the product. After the adhesive cures, it can provide support for the product flange, enhance the strength of the product flange, and prevent the flange from breaking.

7. The method for preparing a light shield with an external aperture structure according to claim 6, characterized in that: The second step of the product molding process is as follows: S1. Assemble the mold, prepare the required template prepreg according to the blanking template, and fill in the R-corner positions on the mold; S2. At the connection between the column end (5) and the cone section (6) of the light shield, apply a layer of carbon cloth or silk cloth, and evenly place the carbon cloth or silk cloth coated with adhesive into the ring groove. S3, loop winding: use yarn to wind in the loop groove, and maintain tension during the winding process to ensure that the fibers do not buckle; S4. Laying: Use prepreg to lay the main body of the sunshade, ensuring symmetrical layup. Use the designed template prepreg for laying the flange surface and the outer aperture. S5. Bag making: Make vacuum bags by sealing the laid prepreg together with the mold. S6. Curing: Use an autoclave for pressure curing; S7. Demolding: Invert the product and remove the core mold from the top of the product. Use foam and release cloth to make a Z-shaped structural beam around the barrel. Soak the release cloth with glue and lay it on the foam. Connect the bottom of the structural beam to the lower flange of the product. Demold after the glue has cured.

8. The method for preparing a light shield with an external aperture structure according to claim 7, characterized in that: In step S3, the theoretical number of winding turns is calculated based on the width and thickness of the girders.

9. The method for preparing a light shield with an external aperture structure according to claim 7, characterized in that: In step S7, the zigzag structural beams are arranged in eight places on the circumference, evenly distributed around the product barrel.

10. The method for preparing a light shield with an external aperture structure according to claim 7, characterized in that: In step S7, the adhesive is an epoxy resin adhesive or a cyanate ester resin adhesive. After the release cloth is soaked in the adhesive, it is laid on the foam beam. After the adhesive cures, a rigid support structure is formed. The prepreg is a carbon fiber reinforced resin-based prepreg. The resin is any one of cyanate ester resin, epoxy resin, bismaleimide resin, polyimide resin, or phthalic acid cyanide resin.

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