Special-shaped air inlet channel wax mold, forming mold and forming process

Abstract

The invention relates to a special-shaped air inlet channel wax mold, a forming mold and a forming process. The special-shaped air inlet channel wax mold comprises a beewax layer, a vulcanized rubber layer, a glass fabric layer and a carbon fiber plain cloth layer from inside to outside, and the beewax layer, the vulcanized rubber layer, the glass fabric layer and the carbon fiber plain cloth layer are cured and formed into the special-shaped air inlet channel wax mold; the forming mold of the special-shaped air inlet channel wax mold comprises a metal mold and a wax mold tool, the wax mold tool is assembled to the metal mold through a positioning disc, a positioning plate and a positioning pin, and a closed cavity is formed by the wax mold tool and the space in the metal mold; the forming process comprises the steps of pouring a primary wax mold, pouring a composite wax mold, and curing the composite wax mold to form the special-shaped air inlet channel wax mold. The device can be recycled, the sizes of the inner profile and the outer profile of the air inlet duct are accurately controlled, the uniformity of a composite material layer of the special-shaped air inlet duct wax mold is guaranteed, the profile of the special-shaped air inlet duct wax mold is lubricated, the thickness is uniform, and the demolding quality of the unmanned aerial vehicle special-shaped air inlet duct wax mold is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite material component forming, in particular to a special-shaped air inlet wax mold, a forming mold and a forming process. BACKGROUND

[0002] The unmanned aerial vehicle air inlet is a key aerodynamic component, and the surface precision and structural strength thereof are extremely high. The traditional composite material air inlet manufacturing process mainly adopts positive mold forming or negative mold forming process, and has problems such as difficult demolding and difficult control of the inner surface quality.

[0003] The wax mold used in the current unmanned aerial vehicle air inlet manufacturing process is a disposable wax mold, which is composed of beeswax. After the unmanned aerial vehicle air inlet is manufactured, the beeswax is directly heated to melt. When manufacturing the next air inlet, the wax mold needs to be re-manufactured, which is time-consuming and costly. For the unmanned aerial vehicle air inlet with a complex surface, the wax mold cannot completely fit the inner surface of the air inlet, and defects such as rough inner surface, uneven thickness and fiber misalignment are easily generated. After the wax mold cools and solidifies, the wax mold shrinks and deforms, and pits are formed on the surface of the wax mold due to the shrinkage during cooling, which is uneven and affects the smoothness of the air inlet surface.

[0004] In view of the above technical problems, the present application provides a special-shaped air inlet wax mold, a forming mold and a forming process. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art, and provides a special-shaped air inlet wax mold, which can be recycled, accurately control the inner and outer surface sizes of the air inlet, and ensure the uniformity of the composite material layer of the special-shaped air inlet wax mold.

[0006] The present application also provides a forming mold for a special-shaped air inlet wax mold, which can improve the demolding quality of the special-shaped air inlet wax mold of the unmanned aerial vehicle, and ensure the lubrication and uniform thickness of the model surface of the special-shaped air inlet wax mold.

[0007] The present application also provides a forming process for a special-shaped air inlet wax mold. The two wax sheets with different thicknesses form a double-stage wax sheet buffer layer design, which effectively solves the shrinkage and deformation problem of the special-shaped air inlet wax mold, ensures the accurate outer surface size and smooth surface of the formed composite wax mold, and improves the demolding quality. The layer sequence and curing process make the special-shaped air inlet wax mold have better interlayer bonding strength. The vulcanized rubber thermal expansion principle is adopted, which effectively solves the problems of high porosity and uneven layer thickness caused by uneven curing pressure in the traditional wax mold manufacturing process, and ensures the high-quality forming of the inner and outer surfaces of the special-shaped air inlet.

[0008] The technical problems of the present application are solved by the following technical solutions: The wax mold of the special-shaped air inlet channel is special-shaped tubular, and comprises, from inside to outside, a beeswax layer, a vulcanized rubber layer, a glass fiber cloth layer and a carbon fiber plain cloth layer; the beeswax layer is shaped into a special-shaped tubular shape by a forming die; the outer surface of the beeswax layer is compounded with the vulcanized rubber layer by the forming die; the glass fiber cloth layer is wrapped and bonded on the outer surface of the vulcanized rubber layer, and the carbon fiber plain cloth layer is wrapped and bonded on the outer surface of the glass fiber cloth layer; and the beeswax layer, the vulcanized rubber layer, the glass fiber cloth layer and the carbon fiber plain cloth layer are cured and formed into the wax mold of the special-shaped air inlet channel.

[0009] Further, the vulcanized rubber layer is composed of vulcanized rubber, the vulcanized rubber is vulcanized silicone rubber; the glass fiber cloth layer is pasted on the outer surface of the vulcanized rubber layer by HY-5288 epoxy resin with a thickness of 0.1 mm; and the carbon fiber plain cloth layer is pasted on the outer surface of the glass fiber cloth layer by HY-5288 epoxy resin with four layers of T300-3K carbon fiber plain cloth.

[0010] A forming die of a wax mold of a special-shaped air inlet channel, the wax mold forming die comprising a metal mold and a wax mold tooling; The metal mold comprises a first module, a second module, a third module and a fourth module, all of which are formed by numerical control processing of 7075 aluminum alloy, and are assembled by screws into a metal mold with a curved cavity inside, and the surface tolerance of the curved cavity of the metal mold is ±0.05 mm; The wax mold tooling comprises a center column and a positioning column, both of which are formed by numerical control processing of 7075 aluminum alloy, and the outer surface tolerance of the center column is ±0.05 mm; The wax mold tooling is assembled onto the metal mold by a positioning disc, a positioning plate and a positioning pin, and a closed cavity is formed between the wax mold tooling and the space inside the metal mold.

[0011] A wax mold forming process of a wax mold of a special-shaped air inlet channel by using a wax mold forming die of a special-shaped air inlet channel, comprising the following steps: Step 1, pouring an initial wax mold: by pasting wax sheets on the surface of the curved cavity of the metal mold, injecting molten beeswax into the closed cavity formed by the wax mold tooling and the metal mold, forming a beeswax layer, and naturally cooling to form an initial wax mold; Step 2, pouring a composite wax mold: by pasting wax sheets on the surface of the curved cavity of the metal mold, injecting vulcanized rubber into the closed cavity formed by the wax mold tooling and the metal mold, forming a vulcanized rubber layer, and naturally cooling to form a composite wax mold; Step 3, curing and forming a special-shaped air inlet channel wax mold from a composite wax mold: sequentially wrapping and bonding a glass fiber cloth layer, a carbon fiber plain cloth layer and a release cloth layer on the surface of the composite wax mold, placing into an oven for heating and curing, and naturally cooling to form a special-shaped air inlet channel wax mold.

[0012] Further, the step 1 pouring the initial wax mold comprises the following steps: Step (1), uniformly adhere 30mm thick wax sheet on the surface of the metal mold curved cavity, and realize ±0.05mm adhesion accuracy through the positioning pin; Step (2), assemble the wax mold tooling to the metal mold through the positioning disc, positioning plate and positioning pin, and form a closed cavity between the wax mold tooling and the space in the metal mold; Step (3), heat the beeswax to a molten state, inject it into the closed cavity through the wax injection hole of the positioning disc, the wax injection temperature is 80±1℃, until the complete filling, form a beeswax layer, and naturally cool to below 40℃ for demolding, form the initial wax mold, and locate it on the center column of the wax mold tooling; Step (4), separate the metal mold, remove the 30mm thick wax sheet, and clean the metal mold.

[0013] Further, the step 2 pouring the composite wax mold comprises the following steps: Step 1), uniformly adhere 5mm thick wax sheet on the surface of the metal mold curved cavity, and realize ±0.05mm adhesion accuracy through the positioning pin; Step 2), assemble the wax mold tooling and the initial wax mold located on the center column of the wax mold tooling into the metal mold curved cavity through the positioning disc, positioning plate and positioning pin, form a closed cavity between the wax mold tooling and the space in the metal mold, and form a 25mm gap between the initial wax mold and the curved cavity of the metal mold after adhering the wax sheet; Step 3), inject vulcanized rubber into the 25mm gap in the closed cavity through the wax injection hole of the positioning disc, form a vulcanized rubber layer, naturally cool to below 40℃ for demolding, form the composite wax mold, and locate it on the center column of the wax mold tooling, the temperature for injecting the vulcanized rubber is 25℃; Step 4), separate the metal mold, remove the 5mm thick wax sheet, and clean the metal mold.

[0014] Further, the step 3 of curing the composite wax mold into the special-shaped intake port wax mold comprises the following steps: Step A, wrap the glass fiber cloth layer and the carbon fiber plain cloth layer on the surface of the composite wax mold in sequence; Step B, wrap the demolding cloth layer on the outer surface of the carbon fiber plain cloth layer; Step C, assemble the wax mold tooling and the composite wax mold wrapped with the glass fiber cloth layer, carbon fiber plain cloth layer and demolding cloth layer on the center column of the wax mold tooling into the metal mold curved cavity through the positioning disc, positioning plate and positioning pin, put it into the curing oven at 70℃ for 0.5 hours, the vulcanized rubber expands under the heat, extrudes the demolding cloth layer, the demolding cloth layer is tightly adhered to the surface of the curved cavity in the metal mold, complete the curing, place it at room temperature for 8 to 10 hours, naturally cool to room temperature for demolding, form the special-shaped intake port wax mold, and locate it on the center column of the wax mold tooling; Step D: Separate the metal mold; Step E: The irregularly shaped air intake wax model located on the central pillar of the wax model fixture is used to manufacture an irregularly shaped air intake. Step F, repeat steps B through D, to create the next irregularly shaped air intake.

[0015] The advantages and positive effects of this invention are: 1. The irregularly shaped air intake wax mold of the present invention comprises, from the inside out, a beeswax layer, a vulcanized rubber layer, a fiberglass cloth layer, and a carbon fiber plain weave cloth layer; the beeswax layer is formed into an irregularly shaped tube using a molding die; the outer surface of the beeswax layer is compositely formed with the vulcanized rubber layer using a molding die; a fiberglass cloth layer is wrapped and bonded to the outer surface of the vulcanized rubber layer, and a carbon fiber plain weave cloth layer is wrapped and bonded to the outer surface of the fiberglass cloth layer; dynamic pressure curing is performed using the thermal expansion of the vulcanized rubber; the composite wax mold is cured to form an irregularly shaped air intake wax mold. The structure of the combination of the beeswax layer and the vulcanized rubber layer enables the irregularly shaped air intake wax mold to be recycled and reused up to 20 times, solving the problem of high cost per use of wax molds. It can be recycled, and the inner and outer surface dimensions of the air intake can be precisely controlled to ensure the uniformity of the composite material layup of the irregularly shaped air intake wax mold.

[0016] 2. The molding die for the irregular air intake wax model of the present invention includes a metal mold and a wax model fixture. The wax model fixture is assembled onto the metal mold through a positioning plate, a positioning plate and a positioning pin. The space between the wax model fixture and the metal mold forms a closed cavity. The central column of the wax model fixture is located in the closed cavity. The positioning pins of the wax model fixture pass through the positioning plates and positioning pins at the left and right ends of the central column, which can improve the demolding quality of the irregular air intake wax model of the UAV and ensure that the inner surface of the irregular air intake wax model is smooth and the thickness is uniform.

[0017] 3. The molding die for the irregularly shaped air intake wax mold of this invention uses a 0.1mm thick fiberglass cloth layer, and an epoxy resin layer is pasted onto the outer surface of the vulcanized rubber layer. The fiberglass cloth has very high single-filament strength, which greatly improves its mechanical properties (tensile, bending, and compressive strength) after being made into cloth. At the same time, it has a low density, exhibiting excellent lightweight and high-strength characteristics, and it bonds well with epoxy resin, improving the wettability and adhesion between the fiberglass cloth layer and the epoxy resin.

[0018] 4. The molding die for the irregularly shaped air intake wax mold of the present invention uses carbon fiber plain weave cloth of model T300-3K, which has extremely high rigidity and strength and is extremely lightweight. It can meet the strength requirements while ensuring the lightweight structure of the irregularly shaped air intake wax mold. Carbon fiber has a negative coefficient of thermal expansion and can not deform under temperature changes, which can meet the temperature requirements when using the irregularly shaped air intake wax mold.

[0019] 5. The molding process of the irregular air intake duct wax mold of the present invention involves bonding 30mm thick wax sheets and 5mm thick wax sheets to the initial wax mold and the composite wax mold respectively. The two different thicknesses of wax sheets form a double-level wax sheet buffer layer design. The staged buffer design of the 30mm initial layer and the 5mm precision layer effectively solves the problem of shrinkage and deformation of the irregular air intake duct wax mold. It avoids the problem of pits and unevenness on the surface of the wax mold caused by cooling and solidification after a single injection of beeswax, which affects the smoothness of the air intake duct surface. It ensures that the outer dimensions of the molded composite wax mold are accurate and the surface is smooth, improving the demolding quality. Its layer sequence and curing process give the irregular air intake duct wax mold better interlayer bonding strength.

[0020] 6. The molding process of the irregular air intake wax mold of the present invention, the function of the release cloth layer is to enable the composite wax mold wrapped with the fiberglass cloth layer and the carbon fiber plain cloth layer to be easily separated from the metal mold, so as to facilitate the removal after making an air intake and avoid the metal mold from sticking together with the composite wax mold wrapped with the fiberglass cloth and the carbon fiber plain cloth.

[0021] 7. The molding process of the irregular air intake duct wax mold of the present invention adopts the principle of thermal expansion of vulcanized rubber to provide adaptive surface pressure. The irregular air intake duct wax mold and the metal mold are effectively bonded, which effectively solves the problem of uneven pressure. It avoids the problems of high porosity and uneven layer thickness caused by uneven curing pressure in the traditional wax mold making process, and ensures high-quality molding of the inner and outer surfaces of the irregular air intake duct. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural schematic diagram of the wax mold forming die for the irregularly shaped air intake duct of the present invention; Figure 2 This is a top view of the irregular-shaped air intake wax mold of the present invention; Figure 3 This is a partial structural schematic diagram of the wax mold forming die for the irregularly shaped air intake duct of the present invention; Figure 4 This is a schematic diagram of the metal mold for the irregularly shaped air intake wax mold of the present invention. Figure 5 This is a partial structural schematic diagram of the metal mold for the irregularly shaped air intake wax mold of the present invention; Figure 6 This is a schematic diagram of the combined structure of the third and fourth modules of the metal mold for the irregular-shaped air intake wax mold of the present invention; Figure 7 This is a schematic diagram of the third module structure of the metal mold for the irregular-shaped air intake wax mold forming mold of the present invention; Figure 8 This is a schematic diagram of the wax mold tooling structure of the irregular-shaped air intake wax mold forming mold of the present invention; Figure 9 This invention utilizes the molding process of an irregularly shaped air intake wax mold to produce an irregularly shaped air intake wax mold; In the picture: 1-Metal mold, 2-First module, 3-Second module, 4-Third module, 5-Fourth module, 6-Wax mold fixture, 7-Positioning post, 8-Center post, 9-Positioning plate, 10-Wax injection hole, 11-Positioning plate, 12-Irregular air intake wax mold. Detailed Implementation

[0023] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0024] Figure 9 As shown, an irregularly shaped air intake duct wax mold 12 is a tubular shape. From the inside out, the wax mold 12 comprises a beeswax layer, a vulcanized rubber layer, a fiberglass cloth layer, and a carbon fiber plain weave cloth layer. The beeswax layer is formed into an irregular tubular shape using a molding die. The outer surface of the beeswax layer is laminated with a vulcanized rubber layer using a molding die. A fiberglass cloth layer is then wrapped and bonded to the outer surface of the vulcanized rubber layer, and a carbon fiber plain weave cloth layer is wrapped and bonded to the outer surface of the fiberglass cloth layer. The beeswax layer, vulcanized rubber layer, fiberglass cloth layer, and carbon fiber plain weave cloth layer are then cured to form the irregularly shaped air intake duct wax mold 12. The beeswax layer uses 80# beeswax heated to a molten state. 80# beeswax is a type of medium-temperature wax with a melting point of 80℃, and its raw materials are beeswax and Derma resin. The wax is injected into the closed cavity through the injection hole 10 of the positioning plate 9, and after cooling, it forms a layer of 0.1mm thick fiberglass cloth, which is then bonded to the outer surface of the vulcanized rubber layer with epoxy resin (brand Huntsman, model HY-5288). The carbon fiber plain weave cloth layer uses model T300-3K (T300 is the carbon fiber model, 3K is the weaving method, indicating that there are 3000 carbon fibers in a bundle) carbon fiber plain weave cloth bonded with epoxy resin (brand Huntsman, model HY-5288). The product (model number HY-5288) has four layers pasted on the outer surface of the fiberglass cloth layer; the vulcanized rubber layer is composed of vulcanized rubber, which is vulcanized HT-9835 type silicone rubber. HT-9835 type silicone rubber is a two-component AB type liquid silicone rubber. Component A is silicone rubber and component B is silicone rubber containing platinum curing agent. After the two components A and B are stirred evenly, they are mixed in a 1:1 ratio, stirred again, and poured into the vulcanizing equipment at a uniform speed. It is vulcanized at 25°C for 3-5 hours.

[0025] The irregularly shaped air intake wax mold 12 is reusable and can be used to manufacture irregularly shaped air intakes, solving the problem of high costs caused by wax molds that can only be used once in existing air intake manufacturing processes. Dynamic pressure curing is achieved using the thermal expansion of vulcanized rubber, and the composite wax mold is cured to form the irregularly shaped air intake wax mold 12. The structure combining beeswax and vulcanized rubber layers allows for the recycling of the irregularly shaped air intake wax mold 12, enabling it to be reused up to 20 times. It allows for cyclical use, precise control of the internal and external dimensions of the air intake, and ensures the uniformity of the composite material layup of the irregularly shaped air intake wax mold 12.

[0026] The fiberglass cloth layer is made of 0.1mm thick fiberglass cloth, and an epoxy resin layer is pasted onto the outer surface of the vulcanized rubber layer. The glass fiber monofilaments in the fiberglass cloth have very high strength, which greatly improves the mechanical properties (tensile, flexural, and compressive strength) after the cloth is made. At the same time, it has a low density, exhibiting excellent lightweight and high-strength characteristics, and it bonds well with epoxy resin, improving the wettability and adhesion between the fiberglass cloth layer and the epoxy resin.

[0027] The carbon fiber plain weave fabric layer uses model T300-3K carbon fiber plain weave fabric, which has extremely high stiffness and strength, and is extremely lightweight. It can meet the strength requirements while ensuring the lightweight structure of the irregular air intake wax mold. Carbon fiber has a negative coefficient of thermal expansion, so it will not deform under temperature changes, which can meet the temperature requirements when using irregular air intake wax molds.

[0028] Figures 1 to 8 As shown, a molding die for an irregularly shaped air intake wax model 12 is provided. The molding die includes a metal mold 1 and a wax model fixture 6. The metal mold 1 includes a first module 2, a second module 3, a third module 4, and a fourth module 5. The first module 2, the second module 3, the third module 4, and the fourth module 5 are all CNC machined from 7075 aluminum alloy and assembled with screws to form a metal mold 1 with an internal curved cavity. The surface tolerance of the curved cavity of the metal mold 1 is ±0.05mm. The wax model fixture 6... The system includes a central pillar 8 and positioning pillars 7, located at the left and right ends of the central pillar 8, respectively. Both the central pillar 8 and positioning pillars 7 are CNC machined from 7075 aluminum alloy, with a surface tolerance of ±0.05mm for the central pillar 8. A wax model fixture 6 is assembled onto the metal mold 1 via positioning discs 9, positioning plates 11, and positioning pins. The wax model fixture 6 and the space within the metal mold 1 form a closed cavity, with the central pillar 8 located within this cavity. The positioning pillars 7 pass through the positioning discs 9 and positioning plates 11 at the left and right ends of the central pillar 8, respectively. The molding die for the irregularly shaped air intake wax model 12 improves the demolding quality of the UAV's irregularly shaped air intake wax model 12, ensuring a smooth surface and uniform thickness.

[0029] A wax mold forming process for irregularly shaped air intake ducts using an irregularly shaped air intake duct wax mold forming mold includes the following steps: Step 1, Casting the initial wax mold: By attaching a wax sheet (Sheet Wax 266, manufactured by Jiaruijie, yellowish-brown semi-transparent, with a thermal stability temperature of 130℃) to the surface of the curved cavity of the metal mold 1, molten beeswax is injected into the closed cavity formed by the wax mold fixture 6 and the metal mold 1 to form a beeswax layer. After natural cooling, the initial wax mold is formed.

[0030] Step (1): A 30mm thick wax sheet is evenly attached to the surface of the curved cavity of the metal mold 1, which is composed of the first module 2, the second module 3, the third module 4 and the fourth module 5. The fitting accuracy of ±0.05mm is achieved by using positioning pins to ensure that the outer surface dimensions of the initial wax mold are accurate and the surface is smooth, thereby improving the demolding quality. Step (2): Assemble the wax model fixture 6 onto the metal mold 1 through the positioning plate 9, positioning plate 11 and positioning pin. The central column 8 of the wax model fixture 6 is located in the closed cavity formed by the space between the wax model fixture 6 and the metal mold 1. The positioning columns 7 of the wax model fixture 6 pass through the positioning plates 9 and positioning plates 11 at the left and right ends of the central column 8 respectively. Step (3): Heat 80# beeswax to a molten state and inject it into the closed cavity through the wax injection hole 10 of the positioning plate 9. The wax injection temperature is 80±1℃ until the mold is fully filled and a beeswax layer is formed. Let it cool naturally to below 40℃ to demold and form a preliminary wax mold, which is located on the central column 8 of the wax mold fixture 6. Step (4): Separate metal mold 1, remove the 30mm thick wax sheet, and clean metal mold 1.

[0031] Step 2, Casting the composite wax mold: Wax sheets are attached to the surface of the curved cavity of the metal mold 1, and vulcanized rubber is injected into the closed cavity formed by the wax mold fixture 6 and the metal mold 1 to form a vulcanized rubber layer. After natural cooling, a composite wax mold is formed.

[0032] Step 1) Evenly attach a 5mm thick wax sheet to the surface of the curved cavity of the metal mold 1, which is composed of the first module 2, the second module 3, the third module 4 and the fourth module 5. A fitting accuracy of ±0.05mm is achieved by using positioning pins to ensure that the outer surface dimensions of the molded composite wax mold are accurate and the surface is smooth, thereby improving the demolding quality. Step 2) The wax model fixture 6 and the initial wax model located on the central column 8 of the wax model fixture 6 are assembled into the curved cavity of the metal mold 1 by the positioning plate 9, the positioning plate 11 and the positioning pin. The wax model fixture 6 and the space inside the metal mold 1 form a closed cavity. The initial wax model and the curved cavity of the metal mold 1 after the wax sheet is attached form a 25mm gap. Step 3) Inject vulcanized rubber into the 25mm gap in the closed cavity through the wax injection hole 10 of the positioning plate 9 to form a vulcanized rubber layer. Let it cool naturally to below 40℃ to demold, forming a composite wax mold, which is located on the central column 8 of the wax mold tooling 6. The temperature of the vulcanized rubber injected is 25℃. Step 4) Separate metal mold 1, remove the 5mm thick wax sheet, and clean metal mold 1.

[0033] Step 3: Curing the composite wax mold to form the irregularly shaped air intake wax mold 12: Gradually wrap the surface of the composite wax mold with a fiberglass cloth layer, a carbon fiber plain weave cloth layer and a release cloth layer, place it in an oven for heating and curing, and after natural cooling, form the irregularly shaped air intake wax mold 12.

[0034] Step A: Sequentially wrap and bond a layer of fiberglass cloth and a layer of carbon fiber plain weave cloth on the surface of the composite wax mold. Apply a 0.1mm thick layer of fiberglass cloth to the surface of the composite wax mold using epoxy resin (brand: Huntsman, model: HY-5288). Apply four layers of T300-3K carbon fiber plain weave cloth to the surface of the 0.1mm thick fiberglass cloth using epoxy resin (brand: Huntsman, model: HY-5288). Step B: Apply epoxy resin (brand Huntsman, model HY-5288) to the surface of the outer T300-3K carbon fiber plain weave fabric to bond and release the mold cloth layer. The purpose of the release cloth is to allow the composite wax mold wrapped with the fiberglass cloth layer and the carbon fiber plain weave fabric layer to be easily separated from the metal mold 1, so as to facilitate the removal after making an air intake channel, and to prevent the metal mold 1 from sticking to the composite wax mold wrapped with the fiberglass cloth layer and the carbon fiber plain weave fabric layer. Step C: Using the positioning plate 9, positioning plate 11 and positioning pin, assemble the wax model fixture 6 and the composite wax model with the fiberglass cloth layer, carbon fiber plain cloth layer and release cloth layer wrapped on the central column 8 of the wax model fixture 6 into the curved cavity of the metal mold 1. Place it in the oven at 70°C for 0.5 hours to heat and cure. The vulcanized rubber expands when heated, squeezing the release cloth layer. The release cloth of the release cloth layer adheres tightly to the surface of the curved cavity inside the metal mold 1 to complete the curing. Place it at room temperature for 8 to 10 hours, and let it cool naturally to room temperature to demold, forming the irregular air intake wax model 12, which is located on the central column 8 of the wax model fixture 6. Step D: Separate metal mold 1; Step E: The irregularly shaped air intake wax model 12 located on the central pillar 8 of the wax model fixture 6 is used to manufacture an irregularly shaped air intake. Step F, repeat steps B through D, to create the next irregularly shaped air intake.

[0035] The molding process of the irregularly shaped air intake duct wax mold of this invention involves bonding 30mm thick wax sheets and 5mm thick wax sheets to the initial wax mold and composite wax mold respectively. These two different thicknesses of wax sheets form a dual-level wax sheet buffer layer design. The staged buffer design of the 30mm initial layer and the 5mm precision layer effectively solves the shrinkage and deformation problem of the irregularly shaped air intake duct wax mold 12. It avoids the pits and unevenness caused by cooling and solidification after a single injection of beeswax, which affects the smoothness of the air intake duct surface. This ensures the accurate dimensional accuracy and smooth surface of the molded composite wax mold, improving demolding quality. Its layering sequence and curing process give the irregularly shaped air intake duct wax mold 12 better interlayer bonding strength. The function of the release cloth layer is to allow the composite wax mold wrapped with the fiberglass cloth layer and carbon fiber plain weave cloth layer to easily separate from the metal mold 1, facilitating disassembly after one air intake duct is made, and preventing the metal mold 1 from sticking to the composite wax mold wrapped with the fiberglass cloth and carbon fiber plain weave cloth. By adopting the principle of thermal expansion of vulcanized rubber, adaptive surface pressure is provided, and the irregular air intake wax mold 12 and metal mold 1 are effectively fitted together, which effectively solves the problem of uneven pressure. This avoids the problems of high porosity and uneven layer thickness caused by uneven curing pressure in the traditional wax mold making process, and ensures high-quality molding of the inner and outer surfaces of the irregular air intake.

[0036] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A wax model of an irregularly shaped air intake duct, characterized in that: The irregularly shaped air intake wax mold (12) is an irregularly shaped tubular shape. The irregularly shaped air intake wax mold (12) includes a beeswax layer, a vulcanized rubber layer, a fiberglass cloth layer and a carbon fiber plain weave cloth layer from the inside to the outside. The beeswax layer is formed into an irregularly shaped tubular shape using a molding mold. The vulcanized rubber layer is compositely formed on the outer surface of the beeswax layer using a molding mold. A fiberglass cloth layer is wrapped and bonded to the outer surface of the vulcanized rubber layer, and a carbon fiber plain weave cloth layer is wrapped and bonded to the outer surface of the fiberglass cloth layer. The beeswax layer, vulcanized rubber layer, fiberglass cloth layer and carbon fiber plain weave cloth layer are cured and formed into an irregularly shaped air intake wax mold (12).

2. The irregularly shaped air intake wax model according to claim 1, characterized in that: The vulcanized rubber layer is composed of vulcanized rubber, which is vulcanized silicone rubber; the fiberglass cloth layer is made of 0.1mm thick fiberglass cloth, which is pasted onto the outer surface of the vulcanized rubber layer with HY-5288 epoxy resin; the carbon fiber plain weave cloth layer is made of T300-3K carbon fiber plain weave cloth, which is pasted onto the outer surface of the fiberglass cloth layer with HY-5288 epoxy resin in four layers.

3. A molding die for a wax mold of an irregularly shaped air intake duct as described in claim 1, characterized in that: The irregularly shaped air intake wax mold includes a metal mold (1) and a wax mold tooling (6). The metal mold (1) includes a first module (2), a second module (3), a third module (4) and a fourth module (5). The first module (2), the second module (3), the third module (4) and the fourth module (5) are all CNC machined from 7075 aluminum alloy and assembled into a metal mold (1) with a curved cavity inside by screws. The surface tolerance of the curved cavity of the metal mold (1) is ±0.05mm. The wax model fixture (6) includes a central column (8) and a positioning column (7). The central column (8) and the positioning column (7) are formed by CNC machining of 7075 aluminum alloy. The outer surface tolerance of the central column (8) is ±0.05mm. The wax model fixture (6) is assembled onto the metal mold (1) via a positioning plate (9), a positioning plate (11), and a positioning pin. The wax model fixture (6) and the space inside the metal mold (1) form a closed cavity.

4. A wax mold forming process for irregularly shaped air intake ducts using the wax mold forming die of claim 3, characterized in that: Includes the following steps: Step 1, casting the initial wax mold: By attaching wax sheets to the surface of the curved cavity of the metal mold (1), molten beeswax is injected into the closed cavity formed by the wax mold fixture (6) and the metal mold (1) to form a beeswax layer. After natural cooling, the initial wax mold is formed. Step 2, Casting composite wax mold: Wax sheets are attached to the surface of the curved cavity of the metal mold (1), and vulcanized rubber is injected into the closed cavity formed by the wax mold fixture (6) and the metal mold (1) to form a vulcanized rubber layer. After natural cooling, a composite wax mold is formed. Step 3: Curing the composite wax mold to form an irregularly shaped air intake wax mold (12): Wrap the surface of the composite wax mold with a layer of fiberglass cloth, a layer of carbon fiber plain cloth and a layer of release cloth in sequence, put it in the oven for heating and curing, and after natural cooling, form an irregularly shaped air intake wax mold (12).

5. The irregular air intake duct wax mold forming process according to claim 4, characterized in that: Step 1, pouring the initial wax mold, includes the following steps: Step (1): A 30mm thick wax sheet is evenly attached to the surface of the curved cavity of the metal mold (1), and a fitting accuracy of ±0.05mm is achieved by using a positioning pin; Step (2): Assemble the wax model fixture (6) onto the metal mold (1) using the positioning plate (9), positioning plate (11) and positioning pin. The wax model fixture (6) and the space inside the metal mold (1) form a closed cavity. Step (3): Heat the beeswax to a molten state and inject it into the closed cavity through the wax injection hole (10) of the positioning plate (9). The wax injection temperature is 80±1℃ until the mold is fully filled and a beeswax layer is formed. Let it cool naturally to below 40℃ to demold and form a preliminary wax mold, which is located on the central column (8) of the wax mold fixture (6). Step (4): Separate the metal mold (1), remove the 30mm thick wax sheet, and clean the metal mold (1).

6. The irregular air intake duct wax mold forming process according to claim 4, characterized in that: Step 2, casting the composite wax model, includes the following steps: Step 1) A 5mm thick wax sheet is evenly attached to the surface of the curved cavity of the metal mold (1), and the attachment accuracy of ±0.05mm is achieved by using positioning pins; Step 2) The wax model fixture (6) and the initial wax model on the central column (8) of the wax model fixture (6) are assembled into the curved cavity of the metal mold (1) by means of the positioning plate (9), the positioning plate (11) and the positioning pin. The space between the wax model fixture (6) and the metal mold (1) forms a closed cavity. The initial wax model and the curved cavity of the metal mold (1) after the wax sheet is attached form a 25mm gap. Step 3) Inject vulcanized rubber into the 25mm gap in the closed cavity through the wax injection hole (10) of the positioning plate (9) to form a vulcanized rubber layer. Naturally cool to below 40℃ to demold, forming a composite wax mold, and place it on the central column (8) of the wax mold fixture (6). The temperature of the vulcanized rubber injected is 25℃. Step 4) Separate the metal mold (1), remove the 5mm thick wax sheet, and clean the metal mold (1).

7. The irregular air intake duct wax mold forming process according to claim 4, characterized in that: Step 3, curing the composite wax mold to form the irregularly shaped air intake duct wax mold, includes the following steps: Step A: Sequentially wrap and bond a layer of fiberglass cloth and a layer of carbon fiber plain weave cloth around the surface of the composite wax mold; Step B: Wrap an adhesive release fabric layer around the outer surface of the carbon fiber plain weave fabric layer; Step C: Using the positioning plate (9), positioning plate (11) and positioning pin, assemble the composite wax model of the wax model fixture (6) and the composite wax model of the fiberglass cloth layer, carbon fiber plain cloth layer and release cloth layer on the central column (8) of the wax model fixture (6) into the curved cavity of the metal mold (1). Place it in the oven at 70°C for 0.5 hours to heat and cure. The vulcanized rubber expands when heated, squeezing the release cloth layer. The release cloth layer adheres tightly to the surface of the curved cavity inside the metal mold (1) to complete the curing. Place it at room temperature for 8 to 10 hours, and let it cool naturally to room temperature to demold, forming a special-shaped air intake wax model (12) and placing it on the central column (8) of the wax model fixture (6). Step D: Separate the metal mold (1); Step E: The irregularly shaped air intake wax model (12) located on the central column (8) of the wax model fixture (6) is used to manufacture an irregularly shaped air intake; Step F, repeat steps B through D, to create the next irregularly shaped air intake.

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