A small cavity and double-sided necking cylinder type light shield forming die and forming process

Abstract

The application discloses a small cavity and double-sided necking cylinder type light shield forming die and a forming process, and relates to the technical field of composite material forming. The size and layer number of prepreg of upper and lower flanges, a shell and a thickened area of a product are calculated; the prepreg is cut and pasted on a male die combined structure according to the designed layer number, the upper and lower flanges and the annular thickened area are cross-laid with the whole skin, and vacuumizing is carried out during the layering; the upper flange pressing block and the lower flange pressing block are connected with the male die combined structure through bolts, and pressing is carried out to compress the gap between the upper and lower flanges; the combined die is put into a pressing die as a whole, then a guide column is put in, the pressing die is closed, and the die assembly is completed; and demolding is carried out after heat curing forming. The process is simple, the die has high reliability, can be used for a long time, reduces the labor cost and the material cost, improves the forming quality of the cylindrical part, improves the product yield, is suitable for batch production of product manufacturing, and has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of composite material molding technology, specifically to a small-cavity, double-sided tapered cylindrical light shield molding die and molding process. Background Technology

[0002] Traditional composite material small cavity and double-sided tapered cylindrical light shields are made by first preparing the left and right cylindrical shield bodies and connecting flanges separately through segmented molding. Then, the left and right cylindrical shield bodies are spliced ​​together by adhesive bonding. The main drawback of adhesive bonding is that under large external tensile or shear loads, the obvious interface between the adhesive surfaces of the composite materials makes them prone to breakage.

[0003] There are three existing methods for unibody molding:

[0004] (1) Silicone rubber core mold

[0005] Composite cylindrical sunshades often have internal mounting interfaces, requiring high precision in the product's external surface. While silicone rubber core molds are soft and easy to demold, the soft nature of silicone rubber means that applying pressure to the mold during curing can cause core mold deformation, making it difficult to guarantee product dimensional accuracy. Furthermore, prepreg may contain some gas during layup; due to the elastic and variable nature of the core mold, air bubbles or extruded resin may accumulate between the prepreg layers of the main body, presenting significant uncontrollability. These soft characteristics may pose safety hazards to the quality of sunshade products, reduce product yield, and increase costs, making them unsuitable for products with high requirements for product dimensions and structural strength. Moreover, the coefficient of thermal expansion of silicone rubber gradually decreases with each expansion cycle, resulting in a short effective mold life and high operating costs, making it unsuitable for mass production.

[0006] (2) Soluble disposable mold

[0007] Soluble molds are single-use molds. Soluble molds need to be made before each product production. The process of making soluble molds is complicated. It is necessary to first put into production a soluble casting metal mold, and then use soluble materials to cast the mold (the casting process requires material proportioning, degassing, casting, curing, and demolding). The above production process will significantly increase the labor and material manufacturing costs of the sunshade products, and is not suitable for mass production of products.

[0008] (3) Traditional metal segmented mold

[0009] While existing technologies offer metal combination molds for one-piece molding of small-cavity, double-sided tapered cylindrical light shields, the unreasonable segmentation of the male mold leads to difficulties or even impossibility of demolding, resulting in low product yield. Inaccurate positioning of the male mold causes it to loosen during hot pressing and curing, making it difficult to control the internal molding process and compromising dimensional and structural performance. Simultaneous axial and radial pressure during mold pressing affects mold closing in one direction, leading to failure to close properly in both axial and radial directions. This makes it difficult to guarantee workpiece dimensions and easily results in defects such as out-of-tolerance dimensions, insufficient adhesive on the surface, and loose structure. Consequently, edge grinding and repair are required after thermosetting before use, sometimes even rendering the product unusable. This results in low production efficiency, unstable product quality, and increased production costs. These processes significantly increase the labor and material manufacturing costs of light shield products, making them unsuitable for mass production.

[0010] To solve the above problems, it is particularly necessary to design a new type of small-cavity, double-sided tapered cylindrical light shield molding die and molding process. Summary of the Invention

[0011] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a small cavity and double-sided tapered cylindrical light shield forming mold and forming process. The process is simple, the mold has high reliability, effectively reduces labor and material costs, improves the forming quality of cylindrical parts, increases product yield, is suitable for mass production, and is easy to promote and use.

[0012] To achieve the above objectives, the present invention provides the following technical solution: a small-cavity, double-sided tapered cylindrical light shield forming mold and forming process, comprising a male mold assembly structure and a segmented female mold. The male mold assembly structure includes a core male mold, a segmented male mold, an upper limit male mold, and a lower limit male mold. The segmented female mold includes an upper flange pressure block, a lower flange pressure block, and two segmented pressure molds. The core male mold is inserted into the segmented male mold. The upper part of the core male mold and the segmented male mold are connected to the upper limit male mold via positioning pins, and the lower part of the core male mold and the segmented male mold are connected to the lower limit male mold via positioning pins, forming the male mold assembly structure. The upper flange pressure block and the lower flange pressure block are respectively positioned and connected to the male mold assembly structure via extended bolts. Pressure molds are provided on both sides of the male mold assembly structure and the upper and lower flange pressure blocks.

[0013] Preferably, the segmented male mold is divided into 6 segments, and there is a demolding angle between each segment, which allows them to be removed sequentially. The two ends of the segmented male mold are provided with male mold positioning grooves. There are demolding angles between the segmented male mold and the core mold, the upper limit male mold, and the lower limit male mold, which facilitates demolding.

[0014] Preferably, both the upper limit male mold and the lower limit male mold are provided with guide grooves to facilitate the positioning of the segmented male mold.

[0015] Preferably, the pressure mold is provided with an overflow groove to store the gas and excess adhesive present during the layup process during the curing process.

[0016] Preferably, the core mold male mold and the segmented male mold are both made of 7075 aluminum; the upper limit male mold, the lower limit male mold, the upper flange pressure block, the lower flange pressure block and the pressure mold are all made of P20 steel; the roughness of the contact surfaces of each part of the core mold male mold, the segmented male mold, the upper limit male mold, the lower limit male mold, the upper flange pressure block, the lower flange pressure block and the pressure mold is ≤1.6μm.

[0017] A molding process for a small-cavity, double-sided tapered cylindrical light shield, characterized by the following steps:

[0018] ① Calculate the dimensions and number of prepreg layers for the upper and lower flanges, shell, and thickened area of ​​the product;

[0019] ② Cut the prepreg and lay it on the male mold assembly structure according to the design number of layers. Lay the upper and lower flanges and the circumferential thickening area in a cross pattern with the overall skin to ensure the product thickness. Vacuuming is carried out during the laying process to reduce air bubbles generated during the laying process and improve product quality.

[0020] ③ Connect the upper flange pressure block and the lower flange pressure block to the male mold assembly structure with bolts, and apply pressure to tighten the gap between the upper and lower flanges to ensure the density between the prepreg layers;

[0021] ④ Place the assembled mold into the pressure mold, then place the guide pillars, close the pressure mold, and complete the mold assembly;

[0022] ⑤ Thermosetting molding: Due to the design of the above-mentioned guiding structure, gas and resin will be preferentially discharged from the guiding groove during the thermosetting molding process. At the pressurization point, the radial pressure bolts are manually tightened a second time to ensure the structural strength.

[0023] ⑥ Demold according to the mold design angle.

[0024] Preferably, during mold assembly, the male mold assembly structure and the segmented female mold apply pressure evenly to the workpiece.

[0025] As a preferred method, before heat curing, the mold with the prepreg is placed in a vacuum bag and vacuumed to reduce the air trapped between the prepreg layers; after heat curing, demolding is carried out when the temperature is lowered to 30-50℃, which makes demolding easier.

[0026] The beneficial effects of this invention are: the mold is highly reliable and can be used for a long time, effectively reducing labor and material costs, improving the molding quality of cylindrical parts, increasing product yield, and the mold forming process is simple, suitable for mass production of products, with broad application prospects. Attached Figure Description

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments;

[0028] Figure 1 This is an exploded structural diagram of the mold of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the segmented male mold of the present invention;

[0030] Figure 3 This is a schematic diagram of the assembly structure of the core mold male mold and the lower limit male mold of the present invention;

[0031] Figure 4 This is a schematic diagram of the assembly structure of the core mold male mold, the segmented male mold, and the lower limit male mold of the present invention;

[0032] Figure 5 This is a schematic diagram of the overall assembly of the mold of the present invention. Detailed Implementation

[0033] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0034] Reference Figure 1-5 The specific embodiment adopts the following technical solution: a small cavity and double-sided tapered cylindrical light shield forming mold and forming process, which consists of two parts: a male mold assembly structure and a segmented female mold. The male mold assembly structure includes a core male mold 1, a segmented male mold 2, an upper limit male mold 3, and a lower limit male mold 4. The segmented female mold includes an upper flange pressure block 5, a lower flange pressure block 6, and two segmented pressure molds 7. The core male mold 1 is inserted into the segmented male mold 2. The upper part of the core male mold 1 and the segmented male mold 2 are connected to the upper limit male mold 3 through positioning pins. The lower part of the core male mold 1 and the segmented male mold 2 are connected to the lower limit male mold 4 through positioning pins to form the male mold assembly structure. The upper flange pressure block 5 and the lower flange pressure block 6 are respectively positioned and connected to the male mold assembly structure through extended bolts. Pressure molds 7 are provided on both sides of the male mold assembly structure and the upper flange pressure block 5 and the lower flange pressure block 6.

[0035] It is worth noting that the segmented male mold 2 is divided into 6 segments, and there is a demolding angle between each segment. The segments can be removed in sequence by using the demolding angle. The two ends of the segmented male mold 2 are provided with male mold positioning grooves 8. The segmented male mold 2 and the core mold male mold 1 have a certain demolding angle. The segmented male mold 2 and the upper limit male mold 3 and the lower limit male mold 4 also have a certain demolding angle, which facilitates demolding.

[0036] It is worth noting that both the upper limit male mold 3 and the lower limit male mold 4 are provided with guide grooves 9 to facilitate the positioning of the segmented male mold 2.

[0037] In addition, the pressure mold 7 is provided with an overflow groove at a position 0.5mm away from the edge of the product to store the gas and excess glue present during the curing process. This can prevent the product from being stuck and causing the mold to not close properly, and the space can be used to release gas during the curing process.

[0038] In this specific embodiment, the core mold male mold 1 and the segmented male mold 2 are both made of 7075 aluminum; the upper limit male mold 3, the lower limit male mold 4, the upper flange pressure block 5, the lower flange pressure block 6, and the pressure mold 7 are all made of P20 steel; the roughness of the contact surfaces of each part of the core mold male mold 1, the segmented male mold 2, the upper limit male mold 3, the lower limit male mold 4, the upper flange pressure block 5, the lower flange pressure block 6, and the pressure mold 7 is ≤1.6μm; the roughness of the contact surfaces between each part of the mold and the product is ≤1.6μm.

[0039] In this specific embodiment, the core mold male mold 1 and the segmented male mold 2 are assembled with the upper limit male mold 3 and the lower limit male mold 4 through positioning pins. First, the lower limit male mold 4 is assembled with the core mold male mold 1. Then, the segmented male mold 2 is placed in, and the segmented male mold 2 is positioned by the guide grooves of the upper limit male mold 3 and the lower limit male mold 4. The upper limit male mold 3 is locked with screws. The upper flange pressure block 5 and the lower flange pressure block 6 are positioned and assembled with the overall male mold assembly structure by an extended bolt. After assembly, it is placed in the female mold for curing. The positioning relationship with the female mold is determined by the positioning of the upper flange pressure block 5 and the lower flange pressure block 6. The pressure mold 7 is positioned by guide pillars. The upper flange pressure block 5, the lower flange pressure block 6 and the male mold assembly structure are guided and positioned by the pressure mold 7, thus connecting and positioning the whole. The two-part pressure mold 7 is equipped with guides for pressure application. The upper and lower pressure plates of the press contact the female mold for automatic radial pressure application. Manual radial pressure application is achieved by tightening the bolts through the upper and lower flange pressure plates and the core mold. This ensures that each part is guided and positioned during the pressure application process, and that each surface is evenly pressured when each pressure plate presses against the mold.

[0040] This specific embodiment also discloses a molding process for a small-cavity, double-sided tapered cylindrical light shield, the steps of which are as follows:

[0041] ① Calculate the dimensions and number of prepreg layers for the upper and lower flanges, shell, and thickened area of ​​the product;

[0042] ② Cut the prepreg and lay it on the male mold assembly structure according to the design number of layers. Lay the upper and lower flanges and the circumferential thickening area in a cross pattern with the overall skin to ensure the product thickness. Vacuuming is carried out during the laying process to reduce air bubbles generated during the laying process and improve product quality.

[0043] ③ Connect the upper flange pressure block 5 and the lower flange pressure block 6 to the male mold assembly structure with bolts, and apply pressure to tighten the gap between the upper and lower flanges to ensure the density between the prepreg layers;

[0044] ④ Place the assembled mold into the pressure mold 7, then place the guide pillar, close the pressure mold, and complete the mold assembly;

[0045] ⑤ Thermosetting molding: Due to the design of the above-mentioned guiding structure, gas and resin will be preferentially discharged from the guiding groove during the thermosetting molding process. At the pressurization point, the radial pressure bolts are manually tightened a second time to ensure the structural strength.

[0046] ⑥ Demold according to the mold design angle.

[0047] It is worth noting that when assembling the mold, the male mold assembly structure and the segmented female mold should apply pressure evenly to the workpiece.

[0048] In addition, before thermosetting, the entire mold with the prepreg is placed in a vacuum bag and vacuumed to reduce air trapped between the prepreg layers. After thermosetting, demolding is performed when the temperature drops to 30-50℃, which makes demolding easier.

[0049] This specific embodiment, through the segmented structure design of the male mold, the fixed combination of the segmented molds, the bidirectional independent pressurization design, and the special molding method, enables the regular and controllable discharge of gas and resin from predetermined positions. Furthermore, the molding process does not require mold rotation, making the process simple to operate, easy to demold, and the mold highly reliable and usable for extended periods, effectively reducing labor and material costs. The mold's pressurization methods include cylindrical circumferential pressurization and upper and lower flange pressurization; these two independent pressurization methods do not affect each other, improving product yield. In addition, it ensures the dimensional accuracy of the main body of the workpiece, greatly improving the molding quality of cylindrical parts. After molding, the product requires almost no repair and will not split, demonstrating broad market application prospects.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A mold for forming a small-cavity, double-sided tapered cylindrical light shield, characterized in that, The structure consists of a male mold assembly and a segmented female mold. The male mold assembly includes a core male mold (1), a segmented male mold (2), an upper limit male mold (3), and a lower limit male mold (4). The segmented female mold includes an upper flange pressure block (5), a lower flange pressure block (6), and two segmented pressure molds (7). The core male mold (1) is inserted into the segmented male mold (2). The upper part of the core male mold (1) and the segmented male mold (2) are connected to the upper limit male mold (3) through positioning pins. The lower part of the core male mold (1) and the segmented male mold (2) are connected to the lower limit male mold (4) through positioning pins to form the male mold assembly. The upper flange pressure block (5) and the lower flange pressure block (6) are respectively positioned and connected to the male mold assembly by extension bolts. Pressure molds (7) are provided on both sides of the male mold assembly and the upper flange pressure block (5) and the lower flange pressure block (6).

2. The mold for forming a small-cavity, double-sided tapered cylindrical light shield according to claim 1, characterized in that, The segmented male mold (2) is divided into 6 segments, and each segment is provided with a demolding angle that can be removed in sequence. The two ends of the segmented male mold (2) are provided with male mold positioning grooves (8). The segmented male mold (2) is provided with demolding angles that facilitate demolding between the core mold male mold (1), the upper limit male mold (3), and the lower limit male mold (4).

3. The mold for forming a small-cavity, double-sided tapered cylindrical light shield according to claim 1, characterized in that, The upper limit male mold (3) and the lower limit male mold (4) are both provided with guide grooves (9) to facilitate the positioning of the segmented male mold (2).

4. The mold for forming a small-cavity, double-sided tapered cylindrical light shield according to claim 1, characterized in that, The pressure mold (7) is provided with an overflow tank for storing the gas and excess adhesive present in the layup during the curing process.

5. The mold for forming a small-cavity, double-sided tapered cylindrical light shield according to claim 1, characterized in that, The core mold male mold (1) and the segmented male mold (2) are all made of 7075 aluminum body; the upper limit male mold (3), the lower limit male mold (4), the upper flange pressure block (5), the lower flange pressure block (6) and the pressure mold (7) are all made of P20 steel body.

6. The mold for forming a small-cavity, double-sided tapered cylindrical light shield according to claim 1, characterized in that, The roughness of the contact surfaces of the core mold male mold (1), the segmented male mold (2), the upper limit male mold (3), the lower limit male mold (4), the upper flange pressure block (5), the lower flange pressure block (6), and the pressure mold (7) is ≤1.6μm.

7. A molding process for a small-cavity, double-sided tapered cylindrical light shield, characterized in that, The molding die according to claim 1 includes the following steps: ① Calculate the dimensions and number of prepreg layers for the upper and lower flanges, shell, and thickened area of ​​the product; ② Cut the prepreg and lay it on the male mold assembly structure according to the design number of layers. Lay the upper and lower flanges and the circumferential thickened area in a cross pattern with the overall skin. Vacuuming is carried out during the laying process to reduce the air bubbles generated in the product during the laying process. ③ Connect the upper flange pressure block (5) and the lower flange pressure block (6) to the male mold assembly structure with bolts and apply pressure to tighten the gap between the upper and lower flanges to ensure the density between the prepreg layers; ④ Place the assembled mold into the pressure mold (7), then place the guide pillar, close the pressure mold, and complete the mold assembly; ⑤ Thermosetting molding, and manual tightening of the radial pressure bolts at the pressure points; ⑥ Demolding.

8. The molding process of a small-cavity, double-sided tapered cylindrical light shield according to claim 7, characterized in that, In step ④, when assembling the mold, the male mold assembly structure and the segmented female mold apply pressure evenly to the workpiece.

9. The molding process of a small-cavity, double-sided tapered cylindrical light shield according to claim 7, characterized in that, Before heat curing in step ⑤, the mold with the prepreg is placed in a vacuum bag and vacuumed to reduce air trapped between the prepreg layers.

10. The molding process of a small-cavity, double-sided tapered cylindrical light shield according to claim 7, characterized in that, After thermosetting in step ⑥, demolding is performed when the temperature drops to 30-50℃.

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