Lightweight vehicle door assembly and manufacturing method thereof

Abstract

The invention relates to the technical field of automobile doors, in particular to a light-weight automobile door assembly and a manufacturing method thereof.The automobile door assembly comprises an automobile door outer plate, an automobile door anti-collision beam and an automobile door inner plate, a cavity is formed between the automobile door outer plate and the automobile door inner plate, and the automobile door anti-collision beam is arranged in the cavity; the vehicle door outer plate comprises a first door outer plate body, a second door outer plate body and a first reinforcing rib; the second door outer plate body is located between the first door outer plate body and the first reinforcing rib. The vehicle door outer plate, the vehicle door anti-collision beam and the vehicle door inner plate are all integrally formed through mold pressing injection molding. The composite material has the advantages that the polypropylene continuous glass fiber fabric is combined with the first composite material or the second composite material, and the polypropylene continuous glass fiber fabric / carbon fiber fabric is combined with the second composite material; and the characteristics of low density, high specific strength and high specific stiffness of the composite materials are fully utilized, so that the final product can achieve the weight reduction effect of up to 20%.

Description

Technical Field

[0001] The invention relates to the technical field of automobile doors, and specifically provides a lightweight door assembly and a manufacturing method thereof. Background Art

[0002] Traditional door assemblies are usually divided into integral door assemblies and split door assemblies. Split door assemblies are usually welded into door inner panel assemblies by spot welding, double welding, laser welding and other methods, and then the door outer panel is glued and hemmed to form the door assembly. The integral door assembly stamps the window frame and the door inner panel as a whole, and the manufacturing process of other parts is the same as that of the split door. Usually, the door inner panel, door outer panel, reinforcement plate, etc. are formed by steel plate stamping process, the window frame is formed by rolling process, and the anti-collision beam is formed by steel plate stamping or steel pipe bending and welding. With the rapid development of the new energy vehicle industry and increasingly stringent emission requirements, lightweighting plays a vital role in the development of the automotive industry. Automobile weight reduction has many advantages such as increasing cruising range, enhancing handling, and reducing carbon emissions. As a component with a relatively large weight share, the door assembly has a lot of room for weight reduction, but the current traditional door assemblies are far from meeting the lightweight requirements.

[0003] At present, the mainstream door assembly is made of steel plates stamped into multiple parts, which are combined into an assembly through welding and hemming processes. First of all, the entire door assembly is very heavy. Secondly, the traditional door assembly requires multiple parts to be welded (usually 15-25 parts), which requires additional welding tools and welding processes, making the manufacturing complex and costly. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a lightweight door assembly and a manufacturing method thereof. The door assembly adopts a polypropylene continuous glass fiber fabric, a polypropylene continuous carbon fiber fabric, a first composite material, and a second composite material through a one-piece molding process of compression injection molding to manufacture a door inner panel, a door outer panel, and an anti-collision beam, with a high integration rate and a reduced number of parts. At the same time, the first composite material and the second composite material have the advantages of high specific strength, large specific modulus, recyclability, good bonding, high molding efficiency, and repeatable processing.

[0005] To achieve the above-mentioned purpose, the technical solution created by the present invention is implemented as follows: a lightweight vehicle door assembly, including a vehicle door outer panel, a vehicle door anti-collision beam and a vehicle door inner panel, a cavity is provided between the vehicle door outer panel and the vehicle door inner panel, and the vehicle door anti-collision beam is arranged in the cavity; wherein, the vehicle door outer panel includes a first door outer panel body, a second door outer panel body and a first reinforcing rib; the second door outer panel body is located between the first door outer panel body and the first reinforcing rib; the material of the first door outer panel body is different from the material of the second door outer panel body; the vehicle door outer panel, the vehicle door anti-collision beam and the vehicle door inner panel are all molded as one piece by compression injection molding.

[0006] Furthermore, the second door outer panel body is made of polypropylene continuous glass fiber fabric; the first door outer panel body and the first reinforcing rib are both made of a first composite material including polypropylene, EPDM rubber and 30% talcum powder.

[0007] Furthermore, the second door outer panel body is made of a single layer of polypropylene continuous glass fiber fabric, and the laying direction of the single layer of polypropylene continuous glass fiber fabric is ±45°.

[0008] Furthermore, the vehicle door inner panel includes a door inner panel body and a second reinforcement rib; the door inner panel body is made of multiple layers of polypropylene continuous glass fiber fabric, and the second reinforcement rib is made of a second composite material containing polypropylene and 40% glass fiber.

[0009] Furthermore, the door inner panel body is made of four layers of polypropylene continuous glass fiber fabric, and the plying order of the four layers of polypropylene continuous glass fiber fabric is [±45 / (0 / 90) / (0 / 90) / ±45].

[0010] Furthermore, the door anti-collision beam includes an anti-collision beam body and a third reinforcement rib; the anti-collision beam body is made of a multi-layer mixed fabric including at least two layers of polypropylene continuous glass fiber fabric and at least two layers of polypropylene continuous carbon fiber fabric, and the third reinforcement rib is made of a second composite material including polypropylene and 40% glass fiber.

[0011] Furthermore, the anti-collision beam body is made of eight layers of mixed fabric including two layers of polypropylene continuous glass fiber fabric and six layers of polypropylene continuous carbon fiber fabric, and the plying order of the eight layers of mixed fabric is [±45 / (0 / 90) ±45 / (0 / 90) (0 / 90) / ±45 / (0 / 90) / ±45].

[0012] Furthermore, the first and eighth layers of the ply are polypropylene continuous glass fiber fabrics, and the middle six layers are polypropylene continuous carbon fiber fabrics.

[0013] A method for manufacturing a lightweight vehicle door assembly is used to manufacture the lightweight vehicle door assembly, comprising the following steps: S1: prepare a door outer panel mold, a door anti-collision beam mold and a door inner panel mold, and install the door outer panel mold, the door anti-collision beam mold and the door inner panel mold on corresponding injection molding machines respectively.

[0014] S2: Cutting of single-ply polypropylene continuous glass fabric, four-ply polypropylene continuous glass fabric, and eight-ply mixed fabric.

[0015] S3: putting the single-layer polypropylene continuous glass fiber fabric, the four-layer polypropylene continuous glass fiber fabric and the eight-layer mixed fabric cut in step S2 into a heating furnace for heating respectively.

[0016] S4: The single-layer polypropylene continuous glass fiber fabric, the four-layer polypropylene continuous glass fiber fabric and the eight-layer mixed fabric heated in step S3 are respectively moved to the molds of the corresponding injection molding machines, and the corresponding first composite material or the second composite material is respectively injected after the molds are closed, and a curing treatment is performed. After curing, the molds are opened to take out the molded door outer panel, door inner panel and door anti-collision beam.

[0017] S5: Plasma treatment is performed on the bonding surface of the door anti-collision beam and the bonding surface of the door inner panel, and the door anti-collision beam is bonded to the door inner panel to form a door inner panel assembly; at the same time, the outer surface of the door outer panel is flame treated and then painted, and the inner surface of the door outer panel is plasma treated.

[0018] S6: Glue the door inner panel assembly to the inner surface of the door outer panel to form a door assembly.

[0019] Furthermore, in step S3, the heating temperature of the single-layer polypropylene continuous glass fiber fabric and the four-layer polypropylene continuous glass fiber fabric are both 200° C., and the heating time is 40 seconds; the heating temperature of the eight-layer mixed fabric is 200° C., and the heating time is 50 seconds.

[0020] Compared with the prior art, the present invention can achieve the following beneficial effects: 1) A door outer panel is obtained by combining polypropylene continuous glass fiber fabric with a first composite material (including polypropylene, EPDM rubber and 30% talcum powder), a door inner panel is obtained by combining polypropylene continuous glass fiber fabric with a second composite material (including polypropylene and 40% glass fiber), and a door anti-collision beam is obtained by combining polypropylene continuous glass fiber fabric / carbon fiber fabric with the second composite material, so that the door outer panel, the door inner panel and the door anti-collision beam have the characteristics of low density, high specific strength and high specific stiffness, thereby enabling the final product to achieve a weight reduction effect of up to 20%.

[0021] 2) The one-piece molding process not only supports continuous and high-speed production, thereby significantly improving production efficiency, but also provides greater flexibility in structural design. Compared with traditional stamping and welding processes, this process can integrate the original twenty parts into three parts, which greatly reduces the production process, improves the dimensional accuracy of the parts, and ensures product consistency and quality improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a structural schematic diagram of a lightweight vehicle door assembly provided according to an embodiment of the present invention; Figure 2 is a schematic structural diagram of a door outer panel provided according to an embodiment of the present invention; Figure 3 is a schematic structural diagram of a door inner panel provided according to an embodiment of the present invention; Figure 4 It is a schematic diagram of the structure of a door anti-collision beam provided according to an embodiment of the present invention.

[0023] The accompanying drawings include: 1. vehicle door outer panel; 11. first door outer panel body; 12. second door outer panel body; 13. first reinforcing rib; 2. vehicle door anti-collision beam; 21. anti-collision beam body; 22. third reinforcing rib; 3. vehicle door inner panel; 31. door inner panel body; 32. second reinforcing rib. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0025] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0027] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0028] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0029] like Figures 1 to 4 As shown, a lightweight door assembly provided by an embodiment of the present invention includes a door outer panel 1, a door anti-collision beam 2 and a door inner panel 3. There is a cavity between the door outer panel 1 and the door inner panel 3, and the door anti-collision beam 2 is arranged in the cavity. The door outer panel 1, the door anti-collision beam 2 and the door inner panel 3 are all processed and formed by a compression injection molding integrated molding process.

[0030] The vehicle door outer panel 1 comprises a first door outer panel body 11, a second door outer panel body 12 and a first reinforcing rib 13. The second door outer panel body 12 is located between the first door outer panel body 11 and the first reinforcing rib 13.

[0031] The first door outer panel body 11 and the first reinforcing rib 13 are both made of a first composite material comprising polypropylene, EPDM rubber and 30% talcum powder. This first composite material combines the heat resistance and chemical stability of polypropylene, the aging resistance of EPDM rubber, and the effect of talcum powder in reducing shrinkage and improving rigidity. 30% talcum powder means that the mass of talcum powder accounts for 30% of the total mass of the first composite material. The mass proportion of polypropylene is 40%-60%, and the mass proportion of EPDM rubber is 10%-30%.

[0032] The second door outer panel body 12 is made of a single-layer polypropylene continuous glass fiber fabric, which is a plate-like structure. The laying direction of the single-layer polypropylene continuous glass fiber fabric is ±45°. Among them, the mass proportion of glass fiber in the polypropylene continuous glass fiber fabric is 70%.

[0033] The production process of the door outer panel 1 is as follows: First, the cut single-layer polypropylene continuous glass fiber fabric is placed in an infrared heating furnace for heating at a temperature of 200°C for 40 seconds. Then, the heated single-layer polypropylene continuous glass fiber fabric is transferred to the mold of the injection molding machine by a robot, and the mold is closed and the first composite material containing polypropylene, EPDM rubber and 30% talcum powder is injected. In this process, the first composite material forms the first door outer panel body 11 and the first reinforcement rib 13 respectively, and the single-layer polypropylene continuous glass fiber fabric forms the second door outer panel body 12. After the curing is completed, the mold is opened and the molded door outer panel 1 is taken out.

[0034] In this embodiment, the thickness of the single-layer polypropylene continuous glass fiber fabric is 0.5 mm, that is, the thickness of the second door outer panel body 12 is 0.5 mm. The thickness of the first door outer panel body 11 is 1.5 mm.

[0035] The door inner panel 3 includes a door inner panel body 31 and a second reinforcing rib 32. The door inner panel body 31 is made of multiple layers of polypropylene continuous glass fiber fabric, and the second reinforcing rib 32 is made of a second composite material containing polypropylene and 40% glass fiber. 40% glass fiber means that the mass proportion of glass fiber is 40%, and the glass fiber is short-cut glass fiber, that is, the length of glass fiber is 3-50mm. Due to the reinforcing effect of glass fiber, the second composite material has higher strength and rigidity, and can withstand greater mechanical stress and impact.

[0036] In this embodiment, the door inner panel body 31 is made of four layers of polypropylene continuous glass fiber fabric, and the four layers of polypropylene continuous glass fiber fabric are a plate-like structure. The thickness of each layer of polypropylene continuous glass fiber fabric is 0.5 mm, that is, the thickness of the door inner panel body 31 is 2 mm. The plying order of the four layers of polypropylene continuous glass fiber fabric is [±45 / (0 / 90) / (0 / 90) / ±45]. In the polypropylene continuous glass fiber fabric, the mass proportion of glass fiber is 70%.

[0037] The manufacturing process of the door inner panel 3 is as follows: First, the cut four-layer polypropylene continuous glass fiber fabric is placed in an infrared heating furnace for heating at a temperature of 200°C for 40 seconds. Then, the heated four-layer polypropylene continuous glass fiber fabric is transferred to the mold of the injection molding machine by a robot, and the mold is closed and the second composite material containing polypropylene and 40% glass fiber is injected. In this process, the four-layer polypropylene continuous glass fiber fabric forms the door inner panel body 31, and the second composite material forms the second reinforcement rib 32. After curing is completed, the mold is opened and the molded door inner panel 3 is taken out.

[0038] The door anti-collision beam 2 includes an anti-collision beam body 21 and a third reinforcing rib 22. The anti-collision beam body 21 is made of a multi-layer hybrid fabric including at least two layers of polypropylene continuous glass fiber fabric and at least two layers of polypropylene continuous carbon fiber fabric. The third reinforcing rib 22 is made of a second composite material of polypropylene and 40% glass fiber.

[0039] In this embodiment, the anti-collision beam body 21 is made of eight layers of mixed fabric including two layers of polypropylene continuous glass fiber fabric and six layers of polypropylene continuous carbon fiber fabric, and the eight layers of mixed fabric are plate-like structures. The single-layer thickness of the polypropylene continuous glass fiber fabric and the polypropylene continuous carbon fiber fabric is 0.5 mm, that is, the thickness of the anti-collision beam body 21 is 4 mm. The ply sequence of the eight layers of mixed fabric is [±45 / (0 / 90) ±45 / (0 / 90) (0 / 90) / ±45 / (0 / 90) / ±45]. Among them, the first layer and the eighth layer are polypropylene continuous glass fiber fabrics, and the middle six layers are polypropylene continuous carbon fiber fabrics. In the polypropylene continuous glass fiber fabric, the mass proportion of glass fiber is 70%. In the polypropylene continuous carbon fiber fabric, the mass proportion of carbon fiber is 50%.

[0040] The manufacturing process of the door anti-collision beam 2 is as follows: First, the cut eight layers of hybrid fabric are placed in an infrared heating furnace for heating at a temperature of 200°C for 50 seconds. Then, the heated eight layers of hybrid fabric are transferred to the mold of the injection molding machine by a manipulator, and the mold is closed and the second composite material containing polypropylene and 40% glass fiber is injected. In this process, the eight layers of hybrid fabric form the anti-collision beam body 21, and the second composite material forms the third reinforcement rib 22. After the curing is completed, the mold is opened and the molded door anti-collision beam 2 is taken out.

[0041] A method for manufacturing a lightweight vehicle door assembly is used to manufacture the lightweight vehicle door assembly, comprising the following steps: S1: prepare a door outer panel mold, a door anti-collision beam mold and a door inner panel mold, and install the door outer panel mold, the door anti-collision beam mold and the door inner panel mold on corresponding injection molding machines respectively.

[0042] S2: Cutting a single-layer polypropylene continuous glass fiber fabric, four-layer polypropylene continuous glass fiber fabric, and eight-layer mixed fabric including two layers of polypropylene continuous glass fiber fabric and six layers of polypropylene continuous carbon fiber fabric.

[0043] S3: The single-layer polypropylene continuous glass fiber fabric, the four-layer polypropylene continuous glass fiber fabric and the eight-layer mixed fabric cut in step S2 are respectively placed in an infrared heating furnace by a robot for heating. The heating temperature of the single-layer polypropylene continuous glass fiber fabric and the four-layer polypropylene continuous glass fiber fabric is 200°C, and the heating time is 40s; the heating temperature of the eight-layer mixed fabric is 200°C, and the heating time is 50s.

[0044] The infrared heating furnace and the manipulator are purchased parts. The brand of the infrared heating furnace is Ceramicx, and the model is Ceramicx HPC 1500. The brand of the manipulator is KUKA, and the model is KR QUANTEC PA. The manipulator is equipped with a high-temperature resistant needle-punched clamp, which is used to clamp single-layer polypropylene continuous glass fiber fabric, four-layer polypropylene continuous glass fiber fabric, and eight-layer mixed fabric.

[0045] S4: First, the single-layer polypropylene continuous glass fiber fabric, four-layer polypropylene continuous glass fiber fabric and eight-layer mixed fabric heated in step S3 are moved to the corresponding injection molding machine molds by a robot. Specifically, the single-layer polypropylene continuous glass fiber fabric is moved to the door outer panel mold, the four-layer polypropylene continuous glass fiber fabric is moved to the door inner panel mold, and the eight-layer mixed fabric is moved to the door anti-collision beam mold. Then the molds are closed and the corresponding first composite material or second composite material is injected respectively, that is, the door outer panel mold is injected with the first composite material, and the door inner panel mold and the door anti-collision beam mold are injected with the second composite material. After the injection is completed, a curing treatment is performed. The curing time is 50s-60s, and the curing is performed by circulating water cooling. After the curing is completed, the mold is opened to take out the formed door outer panel 1, door anti-collision beam 2 and door inner panel 3.

[0046] The injection molding machine is a purchased part, and the purchasing manufacturer is Quan Li Fa Machinery Works Co., Ltd., and the model is CLF-1800TWII.

[0047] In this embodiment, the door outer panel 1, the door anti-collision beam 2 and the door inner panel 3 are molded and injection molded at the same time. In some embodiments, the number of injection molding machines cannot meet the requirements of molding and injection molding the door outer panel 1, the door anti-collision beam 2 and the door inner panel 3 at the same time, and they can also be molded separately in batches.

[0048] S5: Plasma treatment is performed on the bonding surface of the door anti-collision beam 2 and the bonding surface of the door inner panel 3, and the door anti-collision beam 2 is bonded to the door inner panel 3 to form a door inner panel assembly; at the same time, the outer surface of the door outer panel 1 is flame treated and then painted, and the inner surface of the door outer panel 1 is plasma treated.

[0049] S6: gluing the vehicle door inner panel assembly to the inner surface of the vehicle door outer panel 1 to form a vehicle door assembly.

[0050] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A lightweight door assembly, characterized in that: It comprises a vehicle door outer panel, a vehicle door anti-collision beam and a vehicle door inner panel, wherein a cavity is provided between the vehicle door outer panel and the vehicle door inner panel, and the vehicle door anti-collision beam is arranged in the cavity; Wherein, the vehicle door outer panel comprises a first door outer panel body, a second door outer panel body and a first reinforcing rib; the second door outer panel body is located between the first door outer panel body and the first reinforcing rib; the material of the first door outer panel body is different from the material of the second door outer panel body; The vehicle door outer panel, vehicle door anti-collision beam and vehicle door inner panel are all integrally formed by compression injection molding.

2. The lightweight door assembly according to claim 1, characterized in that: The second door outer panel body is made of polypropylene continuous glass fiber fabric; The first door outer panel body and the first reinforcing rib are both made of a first composite material including polypropylene, EPDM rubber and 30% talc.

3. The lightweight door assembly according to claim 2, characterized in that: The second door outer panel body is made of a single-layer polypropylene continuous glass fiber fabric, and the laying direction of the single-layer polypropylene continuous glass fiber fabric is ±45°.

4. The lightweight door assembly according to claim 1, characterized in that: The vehicle door inner panel comprises a door inner panel body and a second reinforcing rib; The door inner panel body is made of multiple layers of polypropylene continuous glass fiber fabric, and the second reinforcing rib is made of a second composite material containing polypropylene and 40% glass fiber.

5. The lightweight door assembly according to claim 4, characterized in that: The door inner panel body is made of four layers of polypropylene continuous glass fiber fabric, and the plying order of the four layers of polypropylene continuous glass fiber fabric is [±45 / (0 / 90) / (0 / 90) / ±45].

6. The lightweight door assembly according to claim 1, characterized in that: The door anti-collision beam includes an anti-collision beam body and a third reinforcement rib; the anti-collision beam body is made of a multi-layer mixed fabric including at least two layers of polypropylene continuous glass fiber fabric and at least two layers of polypropylene continuous carbon fiber fabric, and the third reinforcement rib is made of a second composite material including polypropylene and 40% glass fiber.

7. The lightweight door assembly according to claim 6, characterized in that: The anti-collision beam body is made of eight layers of mixed fabric including two layers of polypropylene continuous glass fiber fabric and six layers of polypropylene continuous carbon fiber fabric, and the plying order of the eight layers of mixed fabric is [±45 / (0 / 90) ±45 / (0 / 90) (0 / 90) / ±45 / (0 / 90) / ±45].

8. The lightweight vehicle door assembly according to claim 7, characterized in that: The first and eighth layers of the laminate are polypropylene continuous glass fiber fabrics, and the middle six layers are polypropylene continuous carbon fiber fabrics.

9. A method for manufacturing a lightweight vehicle door assembly, used to manufacture the lightweight vehicle door assembly according to any one of claims 1 to 8, characterized in that: The steps include: S1: preparing a door outer panel mold, a door anti-collision beam mold and a door inner panel mold, and installing the door outer panel mold, the door anti-collision beam mold and the door inner panel mold on corresponding injection molding machines respectively; S2: Cutting a single-layer polypropylene continuous glass fiber fabric, four-layer polypropylene continuous glass fiber fabric, and eight-layer mixed fabric; S3: putting the single-layer polypropylene continuous glass fiber fabric, the four-layer polypropylene continuous glass fiber fabric and the eight-layer mixed fabric cut in step S2 into a heating furnace for heating respectively; S4: moving the single-layer polypropylene continuous glass fiber fabric, the four-layer polypropylene continuous glass fiber fabric and the eight-layer mixed fabric heated in step S3 to the molds of the corresponding injection molding machines, respectively, injecting the corresponding first composite material or the second composite material after the molds are closed, performing a curing treatment, opening the molds after curing, and taking out the molded vehicle door outer panel, vehicle door inner panel and vehicle door anti-collision beam; S5: Plasma treatment is performed on the bonding surface of the door anti-collision beam and the bonding surface of the door inner panel, and the door anti-collision beam is bonded to the door inner panel to form a door inner panel assembly; at the same time, the outer surface of the door outer panel is flame treated and then spray-painted, and the inner surface of the door outer panel is plasma treated; S6: Glue the door inner panel assembly to the inner surface of the door outer panel to form a door assembly.

10. The method for manufacturing a lightweight vehicle door assembly according to claim 9, characterized in that: In step S3, the heating temperature of the single-layer polypropylene continuous glass fiber fabric and the four-layer polypropylene continuous glass fiber fabric are both 200° C. and the heating time is 40 seconds; the heating temperature of the eight-layer mixed fabric is 200° C. and the heating time is 50 seconds.

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