Preparation method of top flow guide cover

Abstract

The invention discloses a preparation method of a top flow guide cover, belongs to the technical field of automobile parts, and aims to solve the problems that the top flow guide cover in the prior art is generally integrally formed and is relatively high in density, meanwhile, structures such as reinforcing ribs are generally required to be mounted, and light weight is not facilitated. The method comprises the steps that a first mold is preheated; accurately heating the first component and the second component; injecting the first component and the second component into the mixing cavity according to a preset proportion, and fully fusing under a preset pressure intensity to obtain a fused component; injecting the fused component into a first mold, pressurizing the first mold for a period of time, opening the first mold, and taking a piece to obtain an outer skin; the outer skin is formed through injection reaction, the inner-layer framework is formed through compression molding, the density of the outer skin is low, the lightweight target can be achieved, the toughness is good, the impact resistance is high, the mounting point BOSS columns are arranged on the inner-layer framework, the outer skin is free of structures such as the mounting point BOSS columns and reinforcing ribs, and the surface quality is good.

Description

TECHNICAL FIELD

[0001] The application relates to a top flow guide cover preparation method and belongs to the technical field of automobile parts. BACKGROUND

[0002] During the operation of a commercial vehicle, air resistance seriously affects the fuel economy of the commercial vehicle. Equipping a top flow guide cover can effectively reduce the air resistance coefficient of the commercial vehicle and improve the fuel economy of the commercial vehicle. The flow guide cover is an air flow guide device arranged on the top of a cab of a commercial vehicle such as a truck or a tractor, and its main function is to effectively reduce the air resistance of the truck during high-speed driving and reduce fuel consumption. The existing common forming process of a new composite material top flow guide cover is SMC integral mold pressing forming, which has a large density and is not conducive to lightweight; or PDCPD integral injection molding, which has shrinkage at the positions of the mounting point BOSS column and the reinforcing rib, poor surface quality, and poor overall rigidity, and generally needs to be additionally arranged with a metal support framework.

[0003] Therefore, the existing top flow guide cover is usually integrally formed, has a large density, usually needs to be arranged with structures such as reinforcing ribs, is not conducive to lightweight, and has poor overall rigidity of the top flow guide cover, which affects the actual use effect of the top flow guide cover. SUMMARY

[0004] The application aims to overcome the deficiencies in the prior art, provide a top flow guide cover preparation method, and realize the lightweight target, good toughness, and high impact resistance of an outer skin through reaction injection forming of the outer skin and mold pressing forming of an inner framework, the mounting point BOSS column is arranged on the inner framework, the outer skin is free of structures such as the mounting point BOSS column and the reinforcing rib, and has good surface quality; and the inner framework has high strength and good rigidity, thereby ensuring the use effect of the top flow guide cover.

[0005] To solve the above technical problems, the application is implemented by using the following technical scheme: The application provides a top flow guide cover preparation method, which comprises the following steps: Preheat the first mold; Accurately heat the first component and the second component; Inject the first component and the second component into the mixing cavity according to a preset ratio, fully fuse under a preset pressure, and obtain a fused component; Inject the fused component into the first mold, pressurize the first mold for a period of time, open the first mold, and take out the outer skin; Preheat the second mold; Cut the material sheet into a size matched with the second mold, assemble the required inlaid nuts into the second mold, spray the demolding agent in the second mold, and stack the plurality of cut material sheets in the second mold; After the second mold is pressurized and lasts for a period of time, the second mold is opened and the inner framework is taken out to obtain the inner framework; The outer skin is bonded with the inner framework to obtain the top fairing.

[0006] Further, the bonding of the outer skin with the inner framework to obtain the top fairing specifically includes: The position where the outer skin and the inner framework need to be bonded is polished, and the release agent at the corresponding position is removed; The outer skin and the inner framework are placed in an environment of 80°C for 40min of drying work, and the water content of the outer skin and the inner framework is reduced to below 0.1%; A predetermined thickness of high-temperature resistant epoxy glue is applied at the position where the outer skin and the inner framework need to be bonded; The outer skin and the inner framework are bonded by the tooling to obtain the top fairing.

[0007] Further, the bonding of the outer skin and the inner framework by the tooling specifically includes: The outer skin and the inner framework are bonded by the tooling at 30°C, the bonding surface of the outer skin and the inner framework is pressurized to 0.5Mpa, then the temperature is raised to 115°C at a rate of 3°C / min, the temperature and pressure are maintained for 30min; The temperature is reduced from 115°C to 80°C at a rate of 2°C / min, and then naturally cooled to obtain the top fairing.

[0008] Further, the preheating temperature of the concave die of the first mold is 75°C, and the preheating temperature of the convex die of the first mold is 60°C; The preheating temperature of the second mold is 150°C.

[0009] Further, the precise temperature rising of the first component and the second component specifically includes: The first component and the second component are stored at a temperature of 15±2°C; The first component and the second component are precisely heated to a temperature of 35±1°C to reduce the viscosity of the first component and the second component to 200mPa·s; Wherein, the temperature difference of the first component and the second component during storage is ≤3°C; the first component is a tungsten-containing catalyst-containing dicyclopentadiene prepolymer, and the second component is a dicyclopentadiene prepolymer containing an alkyl aluminum activator.

[0010] Further, the first component and the second component are injected into the mixing chamber according to the preset ratio, and are fully fused at a preset pressure to obtain the fused component, which specifically includes: The first component and the second component are injected into the mixing cavity through the injection pipeline in a ratio of 1:1, and are sufficiently fused under a pressure of 5 MPa; The injection pipeline temperature is kept at 37±1 DEG C, and the injection speed is kept at 800-900 g / s.

[0011] Further, the first mold is pressurized for a period of time, and then the first mold is opened and the part is taken out to obtain the outer skin, specifically comprising: The first mold is kept at a pressure of 200 t, and after pressure maintaining for 120 s, the first mold is opened and the part is taken out to obtain the outer skin blank; The excess material and the flash of the outer skin blank are cut off to obtain the outer skin.

[0012] Further, the plurality of cut pieces are stacked in the second mold, specifically comprising: The male die of the second mold sprays the release agent; The protective film of the cut piece is torn off, and then the cut pieces are stacked in the form of small above and large below.

[0013] Further, the plurality of cut pieces are stacked in the second mold, further comprising: When the closing stroke of the second mold is about to reach the end point, the closing speed of the second mold is slowed down.

[0014] Further, the second mold is pressurized for a period of time, and then the second mold is opened and the part is taken out to obtain the inner layer skeleton, specifically comprising: The second mold is kept at a pressure of 2500 t, and after pressure maintaining for 90 s, the temperature of the second mold is reduced to 75 DEG C, and then the second mold is opened and the part is taken out to obtain the inner layer skeleton blank; The flash of the inner layer skeleton blank is cut off to obtain the inner layer skeleton; The material of the piece is sheet molding compound.

[0015] Compared with the prior art, the present application has the following beneficial effects: The outer skin is formed by injection reaction molding, and the inner layer skeleton is formed by mold pressing, so that the outer skin has the advantages of low density, lightweight, good toughness and high impact resistance, and the installation point BOSS column is arranged in the inner layer skeleton, the outer skin has no installation point BOSS column and reinforcing rib structure, and has good surface quality; at the same time, the inner layer skeleton has high strength and good rigidity, which ensures the use effect of the top flow guide cover. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a flowchart of a top flow guide cover preparation method according to an embodiment of the present application. DETAILED DESCRIPTION

[0017] The application will be further described below with reference to the drawings. The following examples are only used to more clearly illustrate the technical solutions of the application, and cannot be used to limit the protection scope of the application.

[0018] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application. In addition, the terms "first", "second" and the like are only used for description purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can be explicitly or implicitly included one or more. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0019] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0020] As shown in Figure 1 The present application provides a top flow guide preparation method, comprising the following steps: Preheating the first mold; Precise heating of the first component and the second component; The first component and the second component are injected into the mixing cavity according to the preset ratio, and are fully fused under the preset pressure to obtain the fused component; The fused component is injected into the first mold, the first mold is pressurized and lasts for a period of time, then the first mold is opened and the part is taken out to obtain the outer skin; Preheating the second mold; The material sheet is cut to a size matching the second mold, the required inlaid nut is assembled into the second mold, the release agent is sprayed in the second mold, and the plurality of cut material sheets are stacked in the second mold; The second mold is pressurized and lasts for a period of time, then the second mold is opened and the part is taken out to obtain the inner layer framework; The outer skin is bonded with the inner framework to obtain the top flow guide cover.

[0021] Specifically, the outer skin is PDCPD (polydicyclopentadiene) material, and the inner framework is SMC (sheet molding compound) material.

[0022] In one embodiment, the outer skin is bonded with the inner framework to obtain the top flow guide cover, specifically comprising: The position where the outer skin and the inner framework need to be bonded is polished, and the release agent at the corresponding position is removed; The outer skin and the inner framework are placed in an environment of 80°C for 40 minutes of drying work, and the water content of the outer skin and the inner framework is reduced to below 0.1%; A predetermined thickness of high-temperature-resistant epoxy glue is applied at the position where the outer skin and the inner framework need to be bonded; The outer skin and the inner framework are bonded by a tool to obtain the top flow guide cover.

[0023] In one embodiment, the outer skin and the inner framework are bonded by a tool, specifically comprising: The outer skin and the inner framework are bonded by a tool at an environment of 30°C, and the pressure is 0.5MPa on the bonding surface of the outer skin and the inner framework, then the temperature is raised to 115°C at a heating rate of 3°C / min, and the temperature and pressure are maintained for 30 minutes; The temperature is reduced to 80°C at a cooling rate of 2°C / min from 115°C, and then natural cooling is performed to obtain the top flow guide cover.

[0024] Specifically, first, the position where the PDCPD outer skin and the SMC inner framework need to be bonded is polished with sandpaper (#120), and then the release agent is removed with acetone; second, the PDCPD outer skin and the SMC inner framework are placed in an environment of 80°C for 40 minutes of drying, and the water content is reduced to below 0.1%; further, glue is applied, and high-temperature-resistant epoxy glue DP460 (3M TM ) is applied at the position where the PDCPD outer skin and the SMC inner framework need to be bonded, with a thickness of 0.2mm; further, precise matching bonding of the PDCPD outer skin and the SMC inner framework is performed by a tool at an environment of 30°C, and the pressure is 0.5MPa on the bonding surface after bonding, then the temperature is raised to 115°C at a heating rate of 3°C / min, and the temperature and pressure are maintained for 30 minutes; then, stepwise cooling is performed, and the temperature is reduced to 80°C at a cooling rate of 2°C / min from 115°C, then the tool is moved to a room temperature environment for natural cooling, thereby obtaining a PDCPD outer skin and a SMC inner framework double-layer structure top flow guide cover.

[0025] In an embodiment, the preheating temperature of the female die of the first mold is 75°C, the preheating temperature of the male die of the first mold is 60°C, and the preheating temperature of the second mold is 150°C.

[0026] In an embodiment, the precise temperature rising of the first component and the second component specifically comprises: controlling the temperature of the storage of the first component and the second component to be 15±2°C; precisely raising the temperature of the first component and the second component to 35±1°C to reduce the viscosity of the first component and the second component to 200 mPa·s; wherein the temperature difference of the first component and the second component during storage is controlled to be ≤3°C; the first component is a tungsten-containing catalyst-containing dicyclopentadiene prepolymer, and the second component is an alkyl aluminum activator-containing dicyclopentadiene prepolymer.

[0027] Specifically, to prevent the raw materials of the first component and the second component from self-polymerization and maintain the stability of the activity of the catalyst, the raw materials of the first component and the second component are stored at a temperature of 15±2°C; before injection, the raw materials of the first component and the second component are precisely raised in temperature to 35±1°C in an injection tank to reduce the viscosity of the raw materials of the first component and the second component to about 200 mPa·s; and to prevent the inconsistent molding solidification rate of the raw materials of the first component and the second component, the temperature difference of the raw materials of the first component and the second component is required to be ≤3°C.

[0028] In an embodiment, the first component and the second component are injected into the mixing cavity according to a preset ratio, and are sufficiently fused under a preset pressure to obtain a fused component, which specifically comprises: the first component and the second component are injected into the mixing cavity through the injection pipeline according to a ratio of 1:1 through the discharge port of the mixing cavity, and are sufficiently fused under a pressure of 5 MPa; wherein the temperature of the injection pipeline is maintained at 37±1°C, and the injection speed is maintained at 800-900 g / s to compensate for the heat dissipation of the pipeline.

[0029] In an embodiment, the first mold is pressurized for a period of time, and then the first mold is opened and the part is taken out to obtain an outer skin, which specifically comprises: the first mold is maintained at a pressure of 200 t, and after maintaining the pressure for 120 s, the first mold is opened and the part is taken out to obtain an outer skin rough part; the excess material and the flash of the outer skin rough part are cut off to obtain the outer skin.

[0030] In an embodiment, the plurality of cut pieces are stacked in the second mold, which specifically comprises: the inlaid nut to be pre-embedded is assembled to the corresponding positioning pin, and the male die of the second mold sprays a release agent; The cut piece is torn off the protective film and attention is paid to prevent contamination, and then the cut piece is stacked in the form of small on top and large on the bottom.

[0031] One embodiment of stacking the plurality of cut pieces in the second mold further comprises: When the closing stroke of the second mold is about to reach the end point, the closing speed of the second mold is slowed down; and near the end point of the closing stroke, the closing speed is slowed down to facilitate more effective exhaust.

[0032] One embodiment of pressurizing the second mold for a period of time and then opening the second mold and taking out the product to obtain the inner skeleton comprises: The second mold is maintained at a pressure of 2500t, and after maintaining the pressure for 90s, the temperature of the second mold is lowered to 75 DEG C to prevent thermal deformation such as warping and twisting of the inner skeleton product, and then the second mold is opened and the inner skeleton is taken out to obtain the inner skeleton blank; The flash of the inner skeleton blank is cut off to obtain the inner skeleton; The material of the piece is sheet molding compound.

[0033] The outer skin of the present application is formed by injection reaction molding, and the inner skeleton is formed by mold pressing. The outer skin has low density, good toughness and high impact resistance, and the mounting point BOSS column is arranged in the inner skeleton. The outer skin has no mounting point BOSS column and reinforcing rib structure, and has good surface quality. At the same time, the inner skeleton has high strength and good rigidity, which ensures the use effect of the top flow guide cover.

[0034] The PDCPD outer skin of the present application is bonded and matched with the SMC inner skeleton by high-temperature-resistant epoxy glue DP460. The PDCPD outer skin is light in weight and has good impact resistance, and the SMC inner skeleton effectively improves the overall stability, so that other components are no longer needed to support, and has the characteristics of light weight, impact resistance and high rigidity. Compared with SMC integrated mold pressing, the weight can be reduced by 35%-40%. Compared with PDCPD integrated injection molding, there is no shrinkage on the surface, the surface quality is good, and the bending resistance is improved by about 200%. The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A method for preparing a top fairing, characterized in that, The method comprises the following steps: preheating the first mold; precise temperature rising of the first component and the second component; injection of the first component and the second component into a mixing cavity according to a preset proportion, sufficient fusion under a preset pressure, and obtaining a fused component; injection of the fused component into the first mold, pressurization of the first mold for a period of time, mold opening and part taking of the first mold, and obtaining an outer skin; preheating the second mold; cutting of the material sheet into a size matching the second mold, assembly of a required inlaid nut into the second mold, spraying of a release agent in the second mold, and stacking of a plurality of cut material sheets in the second mold; pressurization of the second mold for a period of time, mold opening and part taking of the second mold, and obtaining an inner framework; bonding of the outer skin and the inner framework, and obtaining a top flow guide cover.

2. The method of making a top flow hood of claim 1, wherein, The bonding of the outer skin and the inner framework, and obtaining the top flow guide cover specifically comprises: polishing of positions where the outer skin and the inner framework need to be bonded, and removing the release agent at the corresponding positions; placing the outer skin and the inner framework in an environment at 80 DEG C for 40 min of drying work, and reducing the water content of the outer skin and the inner framework to below 0.1%; applying a preset thickness of high-temperature-resistant epoxy glue at positions where the outer skin and the inner framework need to be bonded; bonding of the outer skin and the inner framework through a tool, and obtaining the top flow guide cover.

3. The method of claim 2, wherein The bonding of the outer skin and the inner framework through the tool specifically comprises: bonding of the outer skin and the inner framework through the tool in an environment at 30 DEG C, pressurization of 0.5 Mpa on the bonding surface of the outer skin and the inner framework, then temperature rising to 115 DEG C at a temperature rising speed of 3 DEG C / min, and maintaining the temperature and the pressure for 30 min; temperature falling from 115 DEG C to 80 DEG C at a temperature falling speed of 2 DEG C / min, and then natural cooling, and obtaining the top flow guide cover.

4. The method of claim 1, wherein The preheating temperature of the female die of the first mold is 75 DEG C, and the preheating temperature of the male die of the first mold is 60 DEG C; The preheating temperature of the second mold is 150 DEG C.

5. The method of claim 1, wherein The precise temperature rising of the first component and the second component specifically comprises: controlling the first component and the second component to be stored at a temperature of 15+ / -2 DEG C; precise temperature rising of the first component and the second component to a temperature of 35+ / -1 DEG C, so as to reduce the viscosity of the first component and the second component to 200 mPa·s; wherein, the temperature difference of the first component and the second component during storage is less than or equal to 3 DEG C; the first component is a tungsten-containing catalyst-containing dicyclopentadiene prepolymer, and the second component is an alkyl aluminum activator-containing dicyclopentadiene prepolymer.

6. The method of claim 1, wherein The injection of the first component and the second component into the mixing cavity according to the preset proportion, the sufficient fusion under the preset pressure, and the obtaining of the fused component specifically comprise: injection of the first component and the second component into the mixing cavity according to a proportion of 1:1 through an injection pipeline, and sufficient fusion under a pressure of 5 MPa; wherein, the temperature of the injection pipeline is maintained at 37+ / -1 DEG C, and the injection speed is maintained at 800-900 g / s.

7. The method of claim 1, wherein The pressurization of the first mold for a period of time, the mold opening and part taking of the first mold, and the obtaining of the outer skin specifically comprise: The first mold keeps 200t pressure, and after keeping pressure for 120s, the first mold is opened and the outer skin blank is obtained; The excess material and flash of the outer skin blank are cut off, and the outer skin is obtained.

8. The method of claim 1, wherein, The plurality of cut pieces are stacked in the second mold, specifically including: Spraying release agent on the punch of the second mold; The protective film of the cut piece is torn off, and then the cut piece is stacked in the form of small on top and large on bottom.

9. The method of claim 8, wherein, The plurality of cut pieces are stacked in the second mold, further including: When the closing stroke of the second mold is about to reach the end point, the closing speed of the second mold is slowed down.

10. The method of claim 1, wherein, After the second mold is pressurized for a period of time, the second mold is opened and the inner layer framework is obtained, specifically including: The second mold keeps 2500t pressure, and after keeping pressure for 90s, the temperature of the second mold is reduced to 75℃, and then the second mold is opened and the inner layer framework blank is obtained; The flash of the inner layer framework blank is cut off, and the inner layer framework is obtained; The material of the piece is sheet molding compound.

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