Automotive exterior trim part and two-step injection molding method thereof

Abstract

The application provides an automobile exterior part and a two-step injection molding method thereof. The automobile exterior part is designed as a single-body structure, and comprises a first part and a second part. The first part comprises a positioning structure and a mounting structure, and the second part comprises a part body. The root of the first part is fixedly connected with the root of the second part. In the injection molding process, the first part and the second part are injected by using a two-step injection molding method, i.e., the first part is injected first, and then the second part is injected. By using the single-body structure, the part weight caused by the traditional two-body structure is reduced. By using the two-step injection molding method of the automobile exterior part, appearance defects caused by local sudden change of material thickness in the traditional one-step injection molding process are avoided, the appearance quality is optimized, and the lightweight of the automobile exterior part is realized.

Description

Technical Field

[0001] This invention relates to the field of injection molding of automotive exterior parts, and more specifically, this invention provides an automotive exterior part and a two-step injection molding method thereof. Background Technology

[0002] Currently, with the rapid development of the automotive industry, improving the quality of car appearance and lightweighting have become the focus of research for car companies. Improving the quality of car appearance can enhance customer recognition, while lightweighting can reduce carbon dioxide emissions, lower fuel consumption per 100 kilometers, meet national emission requirements, and attract more customers.

[0003] The single-piece one-step injection molding method only considers the lightweighting of automobiles and cannot meet the appearance requirements of parts. Generally, automotive exterior parts require mounting and positioning structures on the back. These complex structures are directly connected to the main body of the part. When both are injected into the mold in one step, the uneven thickness of the part material will cause appearance defects on the surface. If the part is then painted and baked, the internal stress generated during the injection molding process will be released, making the uneven texture of the part surface more prominent and reducing the appearance quality of the part.

[0004] The two-piece one-step injection molding method treats the component as a two-piece structure, consisting of an inner panel and an outer panel. During injection molding, the inner and outer panels are molded separately, and then fixed together using tape or welding after molding. This method mounts the complex mounting and positioning structures onto the inner panel, avoiding direct contact with the component surface and thus preventing surface defects. However, this technology increases the weight of the component, which is detrimental to the lightweighting of automobiles, and the two-piece structure increases investment costs for bonding, welding, and other processes.

[0005] Therefore, there is a need to develop a low-cost, lightweight injection molding method for automotive exterior parts that improves appearance quality. Summary of the Invention

[0006] This invention provides an automotive exterior component and a two-step injection molding method thereof, aiming to produce a low-cost, lightweight automotive exterior component with improved appearance quality.

[0007] To achieve the above objectives, the present invention provides a two-step injection molding method for automotive exterior parts, comprising:

[0008] In the feeding step S1, the injection molding material and the injection mold are added to the injection molding equipment. The automotive exterior parts include a first part and a second part, and the injection mold includes a front mold and a rear mold.

[0009] In injection parameter setting step S2, set the injection pressure, holding pressure, cooling time, and injection mold temperature;

[0010] In the first injection molding step S3, start the injection molding equipment and begin the first injection molding process.

[0011] In the second injection molding step S4, after the first injection molding is completed, rotate the injection molding equipment to begin the second injection molding.

[0012] After the second part of injection molding is completed, determine whether the injection molding was successful. If so, remove the automotive exterior parts. If not, continue to rotate the injection molding equipment and repeat steps S3 and S4 until the injection molding is completed and the automotive exterior parts are removed.

[0013] In one embodiment, in the feeding step S1, the injection mold in the injection molding equipment is set as one or more sets, and one or more injection tasks are set in one cycle.

[0014] In one embodiment, in the feeding step S1, the injection molding equipment is a dual-material rotary injection molding machine.

[0015] In one embodiment, in the injection molding parameter setting step S2, the injection molding parameters are set according to the size and material of the automotive exterior parts, specifically as follows:

[0016] The automotive exterior component is a door panel with a width of one meter. The injection molding parameters are: injection pressure of 30-60 MPa, holding pressure of 0-40 MPa, cooling time of 30-60 seconds, and temperature of the front mold and rear mold of 10-50℃.

[0017] The present invention discloses an automotive exterior component, which is manufactured according to a two-step injection molding method for an automotive exterior component. The automotive exterior component is designed as a single-unit structure. The first part of the automotive exterior component includes a positioning structure and an mounting structure, and the second part includes a part body.

[0018] The first part is fixedly connected to the second part at its root.

[0019] In one embodiment, a partial cutout is provided at the root of the connection between the first part and the second part.

[0020] In one embodiment, a diagonal rib is provided at the root of the connection between the first part and the second part.

[0021] In one embodiment, the root of the connection between the first and second parts is thinned, and the thinning thickness matches the thickness of the main body of the part.

[0022] Furthermore, the main body of the part has a material thickness of 3.2mm, and the material thickness at the root of the connection between the first part and the second part is reduced to 0.7mm-0.8mm.

[0023] In one embodiment, the part body is provided with a fixing element, and the part body has a groove that matches the fixing element.

[0024] An embodiment of the present invention provides an automotive exterior component and its two-step injection molding method, which has the following beneficial effects:

[0025] 1. Appearance optimization: By reducing the thickness of the structure, making partial hollows and performing injection molding in two steps, appearance defects caused by sudden changes in local material thickness are avoided. There are no welding marks on the surface of automotive exterior parts, thus optimizing the appearance quality.

[0026] 2. Lightweight: The monocoque structure eliminates the need for the inner panel structure of the two-piece structure, reducing the weight of the parts. Taking the door panel as an example, the monocoque two-step injection molding method will reduce the weight by nearly 40% compared to the traditional method, resulting in a weight reduction of approximately 1.5 kg per vehicle.

[0027] 3. Cost reduction: The monocoque structure eliminates the costs of inner panels and tapes required in the two-piece structure, as well as the welding or gluing processes, significantly reducing the cost of parts, improving efficiency, and contributing to the overall economic efficiency of the vehicle. Attached Figure Description

[0028] Figure 1 This is a schematic flowchart of a two-step injection molding method for automotive exterior parts according to an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of a single-unit structure of an automotive exterior component according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the first and second parts of an automotive exterior component according to an embodiment of the present invention;

[0031] Figure 4 for Figure 2 Enlarged view of point A in the middle;

[0032] Figure 5 This is a partially hollowed-out schematic diagram of the mounting structure of an automotive exterior component according to an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the root reinforcement of the mounting structure of an automotive exterior component according to an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of the root thinning of an installation structure for an automotive exterior component according to an embodiment of the present invention. Detailed Implementation

[0035] The following detailed description of an embodiment of the present invention is provided in conjunction with the accompanying drawings. The following embodiments are merely descriptive and not limiting, and should not be construed as limiting the scope of protection of the present invention.

[0036] Figure 1 A flowchart of a two-step injection molding method for automotive exterior parts according to an embodiment of the present invention is disclosed, including:

[0037] In the feeding step S1, the injection molding material and the injection mold are added to the injection molding equipment. The automotive exterior parts include a first part and a second part, and the injection mold includes a front mold and a rear mold.

[0038] In injection parameter setting step S2, set the injection pressure, holding pressure, cooling time, and injection mold temperature;

[0039] In the first injection molding step S3, start the injection molding equipment and begin the first injection molding process.

[0040] In the second injection molding step S4, after the first injection molding is completed, rotate the injection molding equipment to begin the second injection molding.

[0041] After the second part of injection molding is completed, determine whether the injection molding was successful. If so, remove the automotive exterior parts. If not, continue to rotate the injection molding equipment and repeat steps S3 and S4 until the injection molding is completed and the automotive exterior parts are removed.

[0042] The steps of a two-step injection molding method for automotive exterior parts according to an embodiment of the present invention will be described in detail below.

[0043] In the feeding step S1, the injection mold in the injection molding equipment is set as one or more sets, and one or more injection tasks are set in one cycle.

[0044] Furthermore, the injection molding equipment is a dual-material rotary injection molding machine.

[0045] In step S2, the injection molding parameters are set according to the size and material of the automotive exterior parts, specifically as follows:

[0046] The automotive exterior component is a door panel with a width of one meter. The injection molding parameters are as follows: the injection pressure is set to 30-60 MPa; to ensure that the small ribs in the door panel structure are injected in place, to avoid gaps during injection and to prevent flash from forming on the edges of the parts, the holding pressure is set to 0-40 MPa; since the door panel is a narrow and long structure, to prevent deformation due to the release of internal stress during the cooling process of the door panel ends, the cooling time is set to 30-60 seconds, and the temperature of the front mold and the rear mold is set to 10-50℃.

[0047] Figure 2This invention discloses an embodiment of an automotive exterior component, which is manufactured according to a two-step injection molding method. The automotive exterior component integrates a conventional inner panel and an outer panel into a single unit, designed as a monolithic structure.

[0048] Furthermore, such as Figure 3 As shown, the first part of the automotive exterior component includes a positioning structure and an installation structure, and the second part includes the main body of the component. The single-piece structure reduces weight by nearly 40% compared to the two-piece structure, resulting in a weight reduction of approximately 1.5 kg per vehicle.

[0049] Among them, such as Figure 4 As shown, the root of the first part is fixedly connected to the second part, which increases the contact area between the structure of the second part and the first part during injection molding, thereby increasing the connection strength between the two.

[0050] In one embodiment, such as Figure 5 As shown, a partial cutout is provided at the root of the connection between the first part and the second part.

[0051] In one embodiment, such as Figure 6 As shown, if the connection strength at the root of the first part and the second part is insufficient, diagonal reinforcement can be added appropriately, but the thickness of the diagonal reinforcement should be less than 0.7mm.

[0052] In one embodiment, such as Figure 7 As shown, the root of the connection between the first and second parts is thinned, and the thinning thickness matches the thickness of the main body of the part. Specifically, the root material thickness needs to match the main body material thickness to meet the dual requirements of part strength and appearance quality.

[0053] The main body of the part has a material thickness of 3.2mm, and the material thickness is 0.7mm-0.8mm after local thinning at the root of the connection between the first part and the second part.

[0054] In one embodiment, such as Figure 2 As shown, the main body of the part is equipped with a fixing element, and the main body of the part is provided with a groove that matches the fixing element.

[0055] It should be noted that relational terms such as "first" and "second" in this text are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, the term "comprising" refers to a process, method, article, or part that includes a series of elements, including not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or part.

[0056] The specific embodiments described above are merely further illustrations of the present invention and are not intended to limit the present invention in any other way. For those skilled in the art, it will be understood that modifications and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A two-step injection molding method for automotive exterior parts, characterized in that, include: In the feeding step S1, the injection molding material and the injection mold are added to the injection molding equipment. The automotive exterior parts include a first part and a second part, and the injection mold includes a front mold and a rear mold. In injection parameter setting step S2, set the injection pressure, holding pressure, cooling time, and injection mold temperature; In the first injection molding step S3, start the injection molding equipment and begin the first injection molding process. In the second injection molding step S4, after the first injection molding is completed, rotate the injection molding equipment to begin the second injection molding. After the second part of injection molding is completed, determine whether the injection molding was successful. If so, remove the automotive exterior parts. If not, continue to rotate the injection molding equipment and repeat steps S3 and S4 until the injection molding is completed and the automotive exterior parts are removed. The automotive exterior component is designed as a single-unit structure. The first part of the automotive exterior component includes a positioning structure and an installation structure. The second part includes a main body of the component. The root of the first part is fixedly connected to the second part, so that the contact surface between the structure of the second part and the first part is increased during injection molding. The root of the connection between the first part and the second part is thinned, and the thinning thickness matches the thickness of the main body of the component. The material thickness of the main body of the component is 3.2mm. After thinning, the material thickness of the root of the connection between the first part and the second part is 0.7mm-0.8mm.

2. The two-step injection molding method for automotive exterior parts according to claim 1, characterized in that, The injection molding equipment is configured with one or more sets of injection molds, and one or more sets of injection tasks are set in one cycle.

3. The two-step injection molding method for automotive exterior parts according to claim 1, characterized in that, The injection molding equipment is a two-material rotary injection molding machine.

4. The two-step injection molding method for automotive exterior parts according to claim 1, characterized in that, The injection molding parameters are set according to the size and material of the automotive exterior parts.

5. A two-step injection molding method for automotive exterior parts according to claim 4, characterized in that, The automotive exterior component is a door panel with a width of one meter. The injection molding parameters are: injection pressure of 30-60 MPa, holding pressure of 0-40 MPa, cooling time of 30-60 seconds, and temperature of the front mold and rear mold of 10-50℃.

6. An automotive exterior component, manufactured using a two-step injection molding method according to claims 1-5, characterized in that, The automotive exterior component is designed as a single-unit structure. The first part of the automotive exterior component includes a positioning structure and an mounting structure, and the second part includes the main body of the component. The root of the first part is fixedly connected to the second part, so that the contact surface between the structure of the second part and the first part is increased during injection molding. The root of the connection between the first part and the second part is thinned, and the thinning thickness matches the thickness of the main body of the part. The material thickness of the main body of the part is 3.2mm, and the material thickness of the root of the connection between the first part and the second part is 0.7mm-0.8mm after thinning.

7. The automotive exterior component according to claim 6, characterized in that, The root of the connection between the first part and the second part has a partial cutout.

8. A car exterior component according to claim 6, characterized in that, A diagonal rib is provided at the root of the connection between the first part and the second part.

9. A car exterior component according to claim 6, characterized in that, The main body of the part is equipped with a fixing element, and the main body of the part is provided with a groove that matches the fixing element.

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