A method for wrapping and molding appearance parts of continuous fiber reinforced composite materials

Abstract

The present invention relates to a continuous fiber reinforced composite material appearance component overlay molding method, after the continuous fiber reinforced composite material part is heated in an oven, it is placed and fixed in the injection mold cavity, and then the mold is closed; the polymer matrix is ​​injected into the mold cavity by an injection molding machine, and the overlay molded continuous fiber reinforced composite material appearance part is obtained after pressure-maintaining cooling and shaping. In the present invention, the heating of the plate can better be compatible with the polymer to achieve a tight adhesion and the surface layer will not fall off. The use of vacuum adsorption can make the plate better fixed and not easy to fall, play a role of precise coating, and avoid the mold from having too many fixed pins to limit the hole position of the part structure design.

Description

Technical Field

[0001] The invention relates to the field of fiber reinforced composite material overmolding, and in particular to an overmolding method for appearance parts of continuous fiber reinforced composite materials. Background Art

[0002] Long Fiber Reinforced Thermoplastic Composites (LFT) uses long fibers (carbon fiber, glass fiber, organic fiber, basalt fiber, stainless steel fiber, etc.) as reinforcing fibers and thermoplastic materials as matrix materials. They are compounded with resins such as PP, PA, and PET through methods such as cable wrapping and online extrusion to obtain composite material pellets or sheets, which are then injected or molded, or directly injected or molded after online mixing to produce structural parts with higher mechanical properties.

[0003] Patent CN107567375A uses an insert injection molding method of fiber-reinforced composite materials and an injection molded product using the same. The reinforcing fiber is immersed in a matrix resin, then cold-formed, and then fixed in a mold cavity for injection molding. This process does not heat the insert, resulting in poor interface bonding, and the injection layer is easy to detach during operation. Summary of the invention

[0004] In view of the defects of the prior art such as poor wettability, low efficiency and poor reliability, the purpose of the present invention is to provide a method for overmolding continuous fiber reinforced composite appearance parts, namely, the composite parts are heated and placed in a mold cavity for fixation, and then coated with resin by in-mold injection molding to obtain fiber reinforced composite appearance parts with smooth surface and stable structure.

[0005] In order to achieve the above objectives, the present invention provides a method for overmolding a continuous fiber reinforced composite material appearance component, comprising: 1) heating a continuous fiber reinforced composite material part in an oven, then placing and fixing the part in a cavity of an injection mold, and then closing the mold;

[0006] (2) The polymer matrix resin is injected into the mold cavity through an injection molding machine, and the polymer resin (5) is coated on the front of the product through injection molding, and then the ribs (4) are injected on the back through the holes (6) of the product. Finally, the continuous fiber reinforced composite appearance part is obtained by pressure-maintaining cooling and shaping.

[0007] The continuous fiber is one of glass fiber, carbon fiber and aramid fiber.

[0008] The matrix resin of the composite material part is one of polypropylene, nylon, polyethylene and epoxy resin.

[0009] The oven is one of an infrared heating oven and a hot air heating oven.

[0010] The heating temperature of the oven is 150-350° C., and the heating time is 1-30 minutes.

[0011] The mold model is a mold cavity containing injection ribs, the mold cavity (1) is a vacuum channel, and the mold (2) is a mold injection hole.

[0012] The vacuum hole mold cavity arrangement diagram, the vacuum hole surface structure is shown as 102, the structure is a shower type, and its structure can effectively avoid the large suction caused by single-port adsorption while ensuring the suction force, which affects the resin blocking the vacuum pipe during injection molding.

[0013] The fixing method is to position the heated continuous fiber reinforced composite material part through positioning pins inside the mold and then fix it by vacuum adsorption.

[0014] The melt heating temperature of the injection molding machine is 150-300° C., and the pressure of the injection molding machine is set to 50-200 bar.

[0015] The granular material is one of polypropylene, nylon and ABS.

[0016] The back rib position (4) is as follows Figure 3 As shown, the polymer resin (5) passes through the holes (6) on the product to achieve the purpose of back injection molding ribs.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (I) Heating the sheet material can make it more compatible with the polymer and achieve a tight adhesion to cover the surface layer without falling off.

[0019] (II) The use of vacuum adsorption can better fix the plate and prevent it from falling, thus playing a role of precise covering and avoiding the structural design of the mold that is restricted by too many fixing pins and holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic side view of a mold cavity of a continuous fiber reinforced composite material appearance component wrapping molding method of the present invention;

[0021] Figure 2 It is a schematic diagram of the mold surface of a method for overwrapping a continuous fiber reinforced composite material appearance component of the present invention;

[0022] Figure 3 A schematic diagram of the principle of a continuous fiber reinforced composite material appearance component overwrapping molding method of the present invention; DETAILED DESCRIPTION

[0023] The following is a further detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0024] Example 1: A composite material part is a composite material product formed by a molding process with continuous glass fiber as reinforcing fiber and polypropylene as matrix resin. The composite material part is placed in an infrared oven, the temperature is set to 180°C and heated for 2 minutes, and the heated part is placed in a mold cavity.

[0025] Injection molding process parameters: injection speed is set to 80% of the system, holding pressure is 75 bar, mold temperature is 60°C, and injection molding machine melt heating temperature is set to 220°C; put the heated composite material part into the mold (such as Figure 1 The composite material part 3 is positioned in the mold cavity by using the ejector pin in the mold cavity, and then fixed by vacuum adsorption. The mold is closed, and polypropylene is injected as the matrix resin to coat and fill the composite material part 3. After holding the pressure for 30 seconds and cooling for 30 seconds, the mold is opened and taken out to obtain a continuous fiber reinforced polypropylene composite material product.

[0026] Example 2: A composite material part is a composite material product formed by a molding process with continuous glass fiber as reinforcing fiber and nylon as matrix resin. The composite material part is placed in a hot air oven, the temperature is set to 250°C and heated for 20 minutes, and the heated part is placed in a mold cavity.

[0027] Injection molding process parameters: injection speed is set to 80% of the system, holding pressure is 70 bar, mold temperature is 60°C, and injection molding machine melt heating temperature is set to 220°C; put the heated composite material part into the injection mold (such as Figure 1 In the mold cavity (as shown in FIG. 1 ), the composite material product 3 is positioned by using the ejector pin in the mold cavity, and then vacuum adsorbed. The mold is closed, and polypropylene is injected as the matrix resin to coat and fill the composite material product 3. After holding the pressure for 30 seconds and cooling for 30 seconds, the mold is opened and taken out to obtain a composite material product of continuous fiber reinforced polynylon coated with polypropylene.

[0028] Example 3: A composite material part is a composite material product formed by a molding process with continuous glass fiber as reinforcing fiber and polypropylene as matrix resin. The composite material part is placed in an infrared oven, the temperature is set to 180°C and heated for 2 minutes, and the heated part is placed in the mold cavity.

[0029] Injection molding process parameters: injection speed is set to 80% of the system, holding pressure is 75 bar, mold temperature is 60°C, and injection molding machine melt heating temperature is set to 270°C; put the heated composite material part into the injection mold (such as Figure 1The composite material part 3 is positioned in the mold cavity by using the ejector pin in the mold cavity, and then vacuum adsorbed. The mold is closed, and nylon is injected as the matrix resin to coat and fill the composite material part 3. After holding the pressure for 30 seconds and cooling for 30 seconds, the mold is opened and taken out to obtain a continuous fiber reinforced polypropylene composite material product coated with nylon on the outside.

[0030] The embodiments of the present invention are provided for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and deform the above embodiments within the scope of the present invention.

[0031] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for overmolding a continuous fiber reinforced composite material appearance component, characterized in that: The method is as follows (1) After heating the continuous fiber reinforced composite material part in an oven, the part is placed in and fixed in the cavity of an injection mold, and then the mold is closed; (2) The polymer matrix is ​​injected into the mold cavity through an injection molding machine, and the polymer resin is coated on the front of the product by injection molding. Then, the ribs are injected on the back through the holes of the product. Finally, the continuous fiber reinforced composite appearance part is obtained by pressure-maintaining cooling and shaping. The method for overmolding a continuous fiber reinforced composite material appearance component according to claim 1, wherein the continuous fiber is one of glass fiber, carbon fiber, and aramid fiber.

2. A method for overmolding a continuous fiber reinforced composite material appearance component according to claim 1, characterized in that: The matrix resin of the composite material part is one of polypropylene, nylon, polyethylene and epoxy resin.

3. The method for overmolding a continuous fiber reinforced composite material appearance component according to claim 1, characterized in that: The composite material product is one of a flat plate, a sheet, and a curved surface product.

4. The method for overmolding a continuous fiber reinforced composite material appearance component according to claim 1, characterized in that: The oven is one of an infrared heating oven and a hot air heating oven.

5. The method for overmolding a continuous fiber reinforced composite material appearance component according to claim 1, characterized in that: The heating temperature of the oven is 150-350° C., and the heating time is 1-30 minutes.

6. The method for overmolding a continuous fiber reinforced composite material appearance component according to claim 1, characterized in that: The mold model is a back-ribless type or a back-ribbed type.

7. The method for overmolding a continuous fiber reinforced composite material appearance component according to claim 1, characterized in that: The fixing method is to position the heated continuous fiber reinforced composite material part through positioning pins inside the mold and then fix it by vacuum adsorption. The method for overmolding a continuous fiber reinforced composite material appearance component according to claim 1, characterized in that: The granular material is one of polypropylene, nylon and ABS.

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