Trial-manufacturing method for automobile mould pressing type parts

Abstract

The invention relates to the technical field of automobile processes, in particular to a trial-manufacturing method for automobile mould pressing type parts. The trial-manufacturing method of the automobile mould pressing type part comprises the following steps: S1, acquiring original data of the automobile mould pressing type part; processing the original data, removing the thickness of the fabric, and performing curvature compensation on the base material to obtain base material model data; s2, the base material model data are imported into a 3D printer, engineering plastic is adopted for 3D printing, and a printed piece is obtained; removing the supporting structure in the printed piece to obtain a base material; and S3, the surface of the base material and the surface of the fabric are coated with an adhesive composition, after drying, the surface of the base material is coated with the fabric in a hot air heating and pressing mode, and a trial-manufactured part is obtained. According to the method, the automobile mould pressing type part is divided into the base material and the fabric, the base material is manufactured through 3D printing, then fabric coating is conducted, the 3D printing and coating technology is optimized, and rapid and low-cost trial manufacturing is achieved.

Description

Technical Field

[0001] This invention relates to the field of automotive manufacturing technology, and in particular to a method for the trial production of molded automotive parts. Background Technology

[0002] Automotive component prototyping is a crucial step in the vehicle development process, with its core tasks being to verify design feasibility, identify potential problems, and optimize process parameters. As the automotive industry accelerates its evolution towards lightweighting, intelligence, and personalization, component prototyping faces unprecedented challenges in terms of technology, cycle time, and cost. According to the "China Automotive Component Prototyping Technology Development Report" released by the China Society of Automotive Engineers in 2024, the current component prototyping cycle has been compressed from the traditional 6-8 weeks to 3-4 weeks, while prototyping costs need to be controlled within 15% of mass production costs, placing higher demands on prototyping technology.

[0003] In the field of prototype manufacturing of automotive interior molded parts (such as carpets, sound insulation pads, trunk side panels, etc.), two main processes are currently used: CNC machining + encapsulation process and silicone mold casting + encapsulation process.

[0004] CNC machining and overlay processes involve using CNC machine tools to cut solid materials to obtain a shaped substrate, which is then covered with a fabric. However, because these molded parts typically have extremely thin walls (generally 1-2 mm, not exceeding 2.5 mm) and complex surface undulations, the material removal rate during CNC machining is as high as 80%-90%, which not only extends the processing cycle (generally requiring 3-5 days) but also results in significant material waste and high trial production costs. According to relevant research data from the 6th issue of "Automotive Technology and Materials" in 2024, the average cost of CNC machining a medium-sized trunk side panel substrate is approximately 800-1200 yuan, of which material costs account for 65%, machining time costs account for 30%, and the remainder is post-processing costs.

[0005] The silicone mold casting + encapsulation process is suitable for situations requiring the production of multiple prototypes. This method first creates a prototype (usually CNC machined), then a silicone mold, and finally produces multiple substrates through a casting process. While this method can reduce the cost per part during mass production, the initial investment in prototype and mold making is significant (prototype production costs approximately 800-1200 RMB, and silicone mold production costs approximately 1500-2500 RMB). Furthermore, the mold has a limited lifespan, typically producing only 20-30 parts. When the prototype production demand is small (e.g., only 5-10 pieces), the mold cost cannot be effectively amortized, resulting in a higher cost per piece than direct CNC machining. In addition, silicone molds are prone to deformation during use, affecting the later precision of the parts and thus interfering with the accuracy of assembly verification.

[0006] It is worth noting that both methods have the following drawbacks: they are difficult to adapt to the increasingly compressed vehicle development cycle. According to the "China Automotive Industry Yearbook 2024," the development cycle of new models by major domestic automakers in 2023 had been shortened to 24 months, a 30% reduction compared to 2018. The efficiency of component prototyping directly affects the overall vehicle development progress. In actual development, it is not uncommon for verification time to be compressed due to excessively long prototyping cycles, or even for some verification stages to be skipped, creating quality risks for subsequent mass production. The "Analysis Report on Quality Problems of Automotive Parts" released by the China Association for Quality in 2023 pointed out that approximately 35% of mass production quality problems stemmed from insufficient prototyping verification, with interior molded parts accounting for as much as 28%.

[0007] More importantly, existing methods have inherent limitations in handling complex surfaces, especially concave structures. CNC machining, due to tool limitations, and silicone molds, because the prototype is CNC machined, both struggle to balance cost and efficiency while maintaining high precision, making it difficult to achieve a perfect balance between speed, low cost, and high precision. This contradiction becomes increasingly prominent, particularly in the early stages of projects with frequent design changes, as it exacerbates the conflict between the rigid processes of traditional prototyping methods and the demands for rapid iteration, becoming a key bottleneck restricting the overall efficiency improvement of automotive R&D.

[0008] In view of this, the present invention is hereby proposed. Summary of the Invention

[0009] The purpose of this invention is to provide a method for prototyping automotive molded parts. The method involves separating the automotive molded parts into a substrate and a fabric. The substrate is made by 3D printing, and then the fabric is applied. The 3D printing and application processes are optimized, which enables rapid and low-cost prototyping and produces high-precision prototypes.

[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: This invention provides a method for prototyping molded automotive parts, comprising the following steps: S1. Obtain the raw data of automotive molded parts; process the raw data, remove the fabric thickness, and perform curvature compensation on the substrate to obtain substrate model data. S2. Import the substrate model data into a 3D printer, and use engineering plastics for 3D printing to obtain a printed part; remove the support structure from the printed part to obtain the substrate; S3. Apply an adhesive composition to the surface of the substrate and the surface of the fabric. After drying, use hot air heating and pressing to wrap the fabric onto the surface of the substrate to obtain a prototype.

[0011] Further, in step S1, the curvature compensation includes: performing size compensation on the area with the largest curvature of the substrate.

[0012] Furthermore, in step S2, the engineering plastic has a tensile strength ≥30MPa and a heat distortion temperature ≥85℃.

[0013] Further, in step S2, the engineering plastic includes at least one of PC / ABS composite material, ASA, nylon, and PETG.

[0014] Furthermore, in step S2, the material of the support structure includes a soluble material.

[0015] Further, in step S2, the method for removing the support structure from the printed part includes: soaking the printed part in a sodium hydroxide solution with a concentration of 5wt%~10wt% for 3~4 hours.

[0016] Further, in step S3, the adhesive composition comprises an adhesive and a curing agent in a mass ratio of 5:1; And / or, the adhesive includes a water-soluble adhesive.

[0017] Further, in step S3, the drying includes drying at 35~60℃ for 20~40 minutes.

[0018] Further, in step S3, when the fabric is needle-punched fabric, the temperature of the hot air heating is 100~120℃; when the fabric is non-woven fabric, the temperature of the hot air heating is 80~100℃; when the fabric is leather, the temperature of the hot air heating is 120~140℃.

[0019] Furthermore, in step S3, the hot air heating and pressing begins from the central area where the substrate has the greatest undulations and gradually extends to the surrounding edges.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a method for prototyping automotive molded parts, which involves separating the automotive molded parts into a substrate and a fabric. The substrate is manufactured by 3D printing, and then the fabric is applied. The 3D printing and application processes are optimized, enabling rapid, low-cost, and high-quality prototyping of automotive molded parts.

[0021] Compared with the traditional CNC method, the trial production method of the present invention for automotive molded parts reduces the trial production cycle by more than 50%.

[0022] Compared with the traditional CNC method, the method for prototyping automotive molded parts of the present invention significantly improves material utilization and reduces the cost of prototyping parts by 40% to 60%.

[0023] The prototypes produced by the method for manufacturing automotive molded parts of the present invention have a stable dimensional accuracy of ±0.2mm, surface quality that meets assembly requirements, and structural strength that meets verification standards. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0025] In some embodiments of the present invention, a method for prototyping automotive molded parts is provided, comprising the following steps: S1. Obtain the raw data of automotive molded parts; process the raw data, remove the fabric thickness, and perform curvature compensation on the substrate to obtain the substrate model data. S2. Import the substrate model data into the 3D printer, use engineering plastics for 3D printing to obtain the printed part; remove the support structure from the printed part to obtain the substrate; S3. Apply an adhesive composition to the surface of the substrate and the surface of the fabric. After drying, use hot air heating and pressing to wrap the fabric onto the surface of the substrate to obtain a prototype.

[0026] The prototyping method of this invention is a prototyping method for automotive molded parts based on 3D printing technology. It breaks down automotive molded parts into a substrate and a cover material. The substrate is produced by 3D printing, and then the cover material is applied. The 3D printing and covering processes are optimized. This method achieves rapid, low-cost, and high-quality prototyping of automotive molded parts, representing a breakthrough in both prototyping efficiency and quality. It solves the problems of long cycle time, high cost, low precision, and poor adaptability in existing automotive molded part prototyping methods.

[0027] The prototyping method of this invention breaks through the technical bottleneck of traditional prototyping methods in processing thin-walled complex structures. By intelligently processing the part data and removing the fabric thickness, the 3D printed substrate avoids the inefficiency caused by the high material removal rate during CNC machining. Secondly, it eliminates the intermediate step of silicone mold making, significantly shortening the prototyping cycle, reducing the prototyping time of a single part from 3-5 days to 1-2 days. Furthermore, by optimizing the 3D printing and coating processes, a balance between accuracy and cost is achieved, reducing the cost of prototyping a single part by 40%-60% compared to CNC machining, while ensuring dimensional accuracy within ±0.2mm, meeting assembly verification requirements.

[0028] In terms of efficiency: Leveraging the digital manufacturing characteristics of 3D printing technology, the direct conversion from design data to physical parts is achieved, eliminating intermediate steps in traditional methods and shortening the trial production cycle by more than 50%. Taking the trial production of a luggage side guard as an example, the traditional CNC method requires approximately 4 days to complete, while the method of this invention can deliver it in just 2 days, significantly improving the speed of R&D iteration.

[0029] In terms of cost: This invention eliminates the need for silicone molds, avoiding high upfront investment. Furthermore, 3D printing boasts a material utilization rate exceeding 90%, compared to only 10%~20% for traditional CNC machining in the production of thin-walled parts, significantly improving material utilization and reducing part prototyping costs by 40%~60%. For example, regarding the side panel of a luggage compartment, compared to traditional CNC methods, the prototyping cost of a single part using this invention is reduced from 800~1200 yuan to 300~500 yuan, significantly lowering production costs.

[0030] In terms of quality: By precisely controlling the 3D printing and coating process, the dimensional accuracy of the parts can be stabilized at ±0.2mm, the surface quality meets the assembly requirements, and the structural strength meets the verification standards, thus solving the accuracy fluctuation problem caused by material removal or mold deformation in traditional CNC methods.

[0031] This invention achieves flexibility and intelligence in the prototyping process, enabling it to better adapt to design changes. When the design is adjusted, only the original data needs to be modified and the prototype reprinted; there is no need to remake molds or adjust CNC programs, resulting in a response speed increase of more than three times. This flexibility allows engineers to perform multiple design iterations in a shorter time, significantly improving design quality. Furthermore, this invention solves the problem of severe material waste in traditional prototyping methods. The additive manufacturing characteristics of 3D printing minimize material consumption, aligning with the current trend of green manufacturing in the automotive industry. Notably, the prototypes produced by this invention have excellent appearance quality and can be directly used in show car production without waiting for mass production molds, saving valuable time for enterprise marketing and creating additional commercial value.

[0032] In some embodiments of the present invention, in step S1, the automotive molded parts include: automotive interior molded parts; for example, carpets, sound insulation pads, and trunk side panels. The automotive molded parts include a substrate and a fabric, wherein the substrate has a relatively thin wall thickness, ≤2.5mm, for example, 1~2mm.

[0033] In some embodiments of the present invention, in step S1, curvature compensation includes: performing dimensional compensation on the area with the largest curvature of the substrate.

[0034] In some embodiments of the present invention, in step S1, the original data is processed to remove the fabric thickness, remove the accessories, and perform size compensation on the area with the largest curvature of the substrate to obtain substrate model data, which is saved in STL format.

[0035] During data processing, the fabric thickness is removed, and accessories such as maintenance covers and standard parts are removed to avoid printing unnecessary structures. Curvature compensation is performed on areas with large undulations to offset part deformation during printing and tensile deformation during the covering process. The processed data is saved in STL format to prepare for 3D printing.

[0036] This invention combines data processing with 3D printing technology. Instead of simply applying 3D printing to the prototyping of automotive parts, it addresses the characteristics of molded thin-walled parts by removing the fabric thickness while simultaneously compensating for the curvature of the substrate. This allows the 3D-printed substrate to perfectly adapt to subsequent overlay processes. This method solves the accuracy problem of traditional 3D printing in applications involving thin-walled complex structures.

[0037] In some embodiments of the present invention, in step S2, the 3D printer includes an FDM 3D printer, that is, an FDM (Fused Deposition Modeling) 3D printing technology is used; the substrate model data is imported into the slicing software of the FDM 3D printer for process planning.

[0038] In some embodiments of the present invention, in step S2, the tensile strength of the engineering plastic is ≥30MPa and the heat distortion temperature is ≥85℃.

[0039] In some embodiments of the present invention, in step S2, the engineering plastic includes at least one of PC / ABS composite material, ASA, nylon and PETG.

[0040] In some preferred embodiments of the present invention, the engineering plastic includes a PC / ABS composite material; the PC / ABS composite material has a tensile strength ≥35MPa, a flexural modulus ≥1800MPa, and a heat distortion temperature ≥95℃. As a printing material, the PC / ABS composite material possesses excellent mechanical properties and thermal stability, making it suitable as a substrate for subsequent coating processes.

[0041] In some embodiments of the present invention, in step S2, the material of the supporting structure includes a soluble material. The present invention does not strictly limit the soluble material; conventional soluble materials are acceptable.

[0042] In some embodiments of the present invention, step S2, the method for removing the support structure in the printed part includes: soaking the printed part in a sodium hydroxide solution with a concentration of 5wt% to 10wt% for 3 to 4 hours.

[0043] The support structure design was optimized, and the support structure was completely removed through a dissolution process, thus avoiding damage to the surface of the parts.

[0044] In some embodiments of the present invention, in step S3, the adhesive composition comprises an adhesive and a curing agent in a mass ratio of 5:1; In some embodiments of the present invention, the adhesive includes a water-soluble adhesive; the water-soluble adhesive uses conventional water-based adhesives for automotive interiors.

[0045] In some embodiments of the present invention, step S3, coating includes spraying. Using a precision spray gun to uniformly spray the adhesive composition onto both the substrate surface and the fabric surface helps ensure uniform coating thickness.

[0046] In some embodiments of the present invention, step S3 includes drying at 35-60°C for 20-40 minutes; preferably, step S3 includes drying at 40°C for 30 minutes.

[0047] After printing, post-processing is performed. First, a water-based adhesive and hardener for automotive interior materials are mixed in a 5:1 ratio and evenly sprayed onto the substrate and fabric surfaces using a precision spray gun. Then, the mixture is dried at 35-60℃ for 20-40 minutes to completely evaporate the moisture and activate the initial tack of the adhesive. This process solves the problems of bubbling and delamination caused by uneven adhesive drying in traditional coating methods.

[0048] In some embodiments of the present invention, in step S3, when the fabric is needle-punched fabric, the hot air heating temperature is 100~120°C; when the fabric is non-woven fabric, the hot air heating temperature is 80~100°C; and when the fabric is leather, the hot air heating temperature is 120~140°C.

[0049] After post-processing, the fabric is coated. This invention uses an intelligent hot air control system to adjust the temperature of the hot air heating according to the fabric type, ensuring that the adhesive is activated at the optimal temperature while avoiding damage to the fabric from high temperature.

[0050] In some embodiments of the present invention, in step S3, hot air heating and pressing begins from the central area where the substrate has the greatest undulations and gradually extends to the surrounding edges.

[0051] Remove the dried substrate and fabric, aligning them precisely, paying particular attention to matching the areas of greatest curvature. Preheat the hot air gun, then begin localized heating from the center of the substrate where the curvature is greatest. Once the adhesive becomes transparent, immediately use a scraper to smoothly press the fabric onto the substrate. Employ a "center-edge" approach, gradually expanding the covering area outwards, pressing each small section firmly with a roller to ensure no air bubbles or wrinkles. After covering, trim excess fabric with a sharp tool, ensuring neat edges. Use a specialized punch to create holes in the fabric at the locations of the holes in the substrate, ensuring precise alignment with the substrate holes. Finally, reinstall the maintenance cover, standard parts, and other accessories to complete the trial production process.

[0052] The coating operation adopts the "center-edge" advancement method, starting from the center area with the greatest surface undulation of the substrate and gradually expanding to the edge, which effectively solves the wrinkling problem in the coating of complex curved surfaces.

[0053] The present invention provides a method for the trial production of automotive molded parts. It intelligently disassembles the structure of automotive molded parts and simplifies the heating and pressing process of multi-layer raw materials into the separation of substrate and fabric. The substrate is quickly produced by FDM (Fused Deposition Modeling) 3D printing technology and then covered with fabric, thus realizing the rapid and low-cost trial production of automotive molded thin-walled parts.

[0054] The method for prototyping automotive molded parts of this invention solves the problem of rapid prototyping of thin-walled complex structures by combining data processing and FDM 3D printing, thus significantly shortening the prototyping cycle. By optimizing material selection and process parameters in the 3D printing process, the dimensional accuracy and structural strength of the printed parts are guaranteed, meeting the assembly verification requirements. By optimizing the coating process, a perfect bond between the fabric and the substrate is achieved, solving the bubbling and delamination problems commonly found in traditional methods.

[0055] In terms of 3D printing technology, in addition to FDM, SLS (Selective Laser Sintering) or MJF (Multi-Jet Fusion) technologies can also be used, but the data processing methods and post-processing processes need to be adjusted accordingly. Regarding coating processes, in addition to water-based adhesives, hot melt adhesives can also be used, but the drying and heating parameters need to be adjusted.

[0056] Example 1 The left side panel of the trunk, as a typical molded automotive part, has a complex three-dimensional curved surface and multiple assembly interfaces. The prototype manufacturing method for the left side panel of the trunk provided in this embodiment includes the following steps: S1. Obtain the original CATIA data of the left side panel of the suitcase and process the data; remove the thickness (approximately 2mm) of the outer needle-punched fabric; remove the maintenance hatch cover, parts at the suitcase hinge opening, and all standard parts; perform 0.15mm dimensional compensation in the area with the greatest curvature; obtain the base material model data, which is saved in STL format to obtain the STL file.

[0057] S2. Import the STL file into the slicing software of the FDM 3D printer for model placement and process planning; use PC / ABS composite material as the substrate and soluble material as the support structure; after slicing, transfer the data to the FDM 3D printer for printing; Before printing, ensure the printer is connected and turned on, and check that the nozzles are clean and unclogging. Load the PC / ABS filament into the consumables compartment and start preheating. After starting printing, monitor the printing process in real time, paying attention to the adhesion of the first layer and the forming quality of complex curved surfaces. The entire printing process takes about 18 hours. After completion, remove the printed part from the platform and carefully peel it off using a scraper. Subsequently, the printed parts are immersed in a 5wt%~10wt% sodium hydroxide solution for 3~4 hours to completely dissolve the support structure. After removal, they are rinsed with clean water. Then, post-processing inspection is carried out to confirm the dimensional accuracy (measured using a coordinate measuring machine with an accuracy of ±0.02mm) and surface quality of key assembly positions, thus obtaining the substrate.

[0058] S3. Prepare the needle-punched fabric for covering (about 2mm thick), cut it according to the unfolded drawing of the part, and leave a 150mm margin at the edge; mix the water-based adhesive and curing agent of the automotive interior with a ratio of 5:1, and spray it evenly on the outer surface of the substrate and the back of the needle-punched fabric with a precision spray gun. Place the sprayed substrate and needle-punched fabric in a 40℃ oven to dry for 30 minutes. Take out the dried substrate and needle-punched fabric, and align them precisely, paying attention to matching the area with the greatest curvature; preheat the hot air gun to 110℃, and start local heating from the center area of ​​the substrate with the greatest undulation. When the adhesive becomes transparent, immediately use a scraper to flatten and press the fabric onto the substrate; use the "center-edge" advancing method to gradually expand the covering area to the surrounding area, and use a roller to compact each small section to ensure no air bubbles or wrinkles. After the covering is completed, use a sharp tool to trim off any excess fabric, keeping the edges neat. At the holes in the substrate, use a special punch to create holes in the needle-punched fabric, ensuring precise alignment with the substrate holes. Finally, reinstall the maintenance cover, standard parts, and other accessories to complete the entire trial production process.

[0059] Actual testing showed that the prototype of the left side panel of the suitcase produced in this embodiment has a dimensional accuracy that can be controlled within ±0.2mm, fully meeting the assembly verification requirements; the surface quality is excellent, with no obvious printing marks or covering defects; structural strength tests show that its bending strength reaches 25MPa, which is sufficient to withstand the load during normal assembly and use; more importantly, the entire trial production cycle only takes 2-3 days and costs about 400 yuan, which is a significant improvement over the traditional CNC method (about 4 days, 1000 yuan).

[0060] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A trial manufacturing method for molded automotive parts, characterized in that, Includes the following steps: S1. Obtain the raw data of automotive molded parts; process the raw data, remove the fabric thickness, and perform curvature compensation on the substrate to obtain substrate model data. S2. Import the substrate model data into a 3D printer, and use engineering plastics for 3D printing to obtain a printed part; remove the support structure from the printed part to obtain the substrate. S3. Apply an adhesive composition to the surface of the substrate and the surface of the fabric. After drying, use hot air heating and pressing to wrap the fabric onto the surface of the substrate to obtain a prototype.

2. The method for trial production of automotive molded parts according to claim 1, characterized in that, In step S1, the curvature compensation includes: performing dimensional compensation on the area with the largest curvature of the substrate.

3. The method for trial production of automotive molded parts according to claim 1, characterized in that, In step S2, the engineering plastic has a tensile strength ≥30MPa and a heat distortion temperature ≥85℃.

4. The method for trial production of automotive molded parts according to claim 1, characterized in that, In step S2, the engineering plastic includes at least one of PC / ABS composite material, ASA, nylon, and PETG.

5. The method for trial production of automotive molded parts according to claim 1, characterized in that, In step S2, the material of the support structure includes a soluble material.

6. The method for trial production of automotive molded parts according to claim 1, characterized in that, In step S2, the method for removing the support structure in the printed part includes: soaking the printed part in a sodium hydroxide solution with a concentration of 5wt%~10wt% for 3~4 hours.

7. The method for trial production of automotive molded parts according to claim 1, characterized in that, In step S3, the adhesive composition comprises an adhesive and a curing agent in a mass ratio of 5:1; And / or, the adhesive includes a water-soluble adhesive.

8. The method for trial production of automotive molded parts according to claim 1, characterized in that, In step S3, the drying includes drying at 35~60℃ for 20~40 minutes.

9. The method for trial production of automotive molded parts according to claim 1, characterized in that, In step S3, when the fabric is needle-punched fabric, the temperature of the hot air heating is 100~120℃; when the fabric is non-woven fabric, the temperature of the hot air heating is 80~100℃; when the fabric is leather, the temperature of the hot air heating is 120~140℃.

10. The method for trial production of automotive molded parts according to claim 1, characterized in that, In step S3, the hot air heating and pressing starts from the central area where the substrate has the greatest undulations and gradually extends to the surrounding edges.