Aoto car plastic body parts moulding

In addition, our company has established cooperative relationships with plastic raw material suppliers, printing manufacturers, etc. to ensure the supply of raw materials and printing quality. Through our rich experience and perfect supply chain, our company can provide customers with high-quality customized aoto car plastic body parts moulding products to meet their specific needs. At the same time, we have 10 years of professional foreign trade service experience, understand the foreign trade process, and better serve our customers. For aoto car plastic body parts moulding products, we can make corresponding plastic parts, which is mainly done through injection molds.

Plastic components for electric vehicles fall into three categories: exterior body panels, functional structural parts, and electrical protective components. Examples include front and rear guards, front cowlings, fenders, footwell covers, battery compartment housings, instrument housings, light brackets, wiring covers, and storage compartments. These products are subjected to prolonged outdoor exposure (sunlight, rain, and temperature fluctuations) as well as continuous vibration and stone impacts during operation. Additionally, battery and electronic control components require electrical insulation and flame retardancy; exterior parts must withstand painting without cracking or yellowing (weather resistance); and load-bearing parts must resist impact without deformation. Common raw materials include ASA and ABS/PC for weather-resistant exterior parts; modified PP and glass-fiber reinforced PP for structural load-bearing parts; PC for transparent light housings; and flame-retardant ABS for electronic control covers. Key molding control points focus on weather resistance and crack prevention, low internal stress, dimensional stability, low VOC emissions, and reliable flame retardancy, as detailed below.

I. Raw Material Selection and Pre-treatment

Raw Material Grading and Regrind Management

Exposed parts such as the vehicle body shell and fenders utilize virgin ASA or ABS/PC, with only a small amount (≤10%) of clean regrind of the same material permitted. The use of regrind is strictly prohibited for battery compartments, load-bearing parts connected to the frame, and flame-retardant electrical housings; regrind can reduce impact strength and compromise flame-retardant systems, leading to cracking upon impact and risks of short-circuiting or fire.

Material blends incorporate anti-UV/weather-resistant masterbatches and low-migration, eco-friendly mold release agents to minimize outdoor surface blooming and interior odors. Flame-retardant and glass-fiber reinforced materials are mixed and stored in separate silos; mixing with standard PP or ABS is prohibited to prevent performance degradation. Glass-fiber modified materials undergo low-speed mixing to prevent fiber breakage, which would otherwise reduce strength and cause surface fiber exposure.

Strict Drying and Dehumidification Standards

ASA, ABS/PC, and PC are highly sensitive to moisture absorption; trace amounts of moisture can cause "silver streaks" and internal micropores, leading to paint defects (such as popping) and brittle failure under impact. ASA and ABS+PC materials undergo hot-air drying at 85°C for 4 hours; PC lamp housings undergo dehumidifying drying at 110°C for 4–6 hours. Modified PP has extremely low water absorption; surface moisture is removed by drying at 60°C for just 1 hour during the rainy season. After drying, raw materials are conveyed via sealed pipelines to prevent re-absorption of workshop moisture.

II. Key Points for Mold Design and Machine Commissioning

Electric vehicle (EV) housings are typically large-area, thin-walled parts (1.8–2.5 mm thick), featuring internal ribs and mounting bosses with wall thicknesses of 3–6 mm. This significant variation in thickness makes them prone to sink marks and warpage; therefore, mold design focuses on balanced cooling, adequate venting, and balanced ejection.

Mold Steel and Structural Optimization

Cavities for cosmetic parts utilize S136 mirror-finish steel, ensuring a scratch- and pit-free surface after polishing that is suitable for painting processes. Cavities for glass-fiber reinforced or flame-retardant parts undergo integral nitriding to resist erosion from fillers and extend service life. All corners feature radii (R-fillets) to eliminate stress concentrations, preventing cracking caused by thermal cycling or vibration. High-precision machining of parting lines minimizes fine flash, preventing assembly hazards (such as pinched fingers) and excessive gaps.

Balanced Cooling System (Crucial for Preventing Warpage)

Protective panels and front housings utilize symmetrical, conformal cooling channels that wrap around the part, while thick-walled bosses incorporate internal spiral cooling cores to minimize temperature differentials between thick and thin sections. Mold temperatures are controlled by zone: 55–65°C for ASA exterior parts; 70–80°C for ABS/PC parts; and 30–45°C for modified PP parts. Excessive PP mold temperatures lead to increased crystallization shrinkage and uneven assembly gaps, while excessively low temperatures result in high residual internal stress, causing slow distortion and deformation during outdoor use.

Venting and Balanced Ejection

Large-area housings involve long melt flow paths. Continuous venting slots (0.012–0.015 mm deep) are machined along the long sides of the parting line, at weld lines, and at the ends of ribs to rapidly evacuate decomposition gases, thereby preventing burning and ensuring adequate weld line strength. For large parts, a balanced ejection system combining multiple ejector pins and ejector blocks is used to prevent localized stress whitening or housing deformation; auxiliary ejector blocks are added for slender fender components.

Mold Installation and Setup Protocols

Large bodywork molds are paired with 500T–1200T injection molding machines; clamping plates must be tightened evenly to withstand high-pressure injection forces and prevent mold opening or flash formation. Water circuits are equipped with flow detectors to verify that each line is free of blockages or leaks. Low-pressure mold protection is calibrated to trigger automatic opening if gate residue is detected, thereby safeguarding the expensive mold cavity. Before producing flame-retardant parts, the barrel is thoroughly purged to eliminate any residual incompatible plastics.

III. Key Control Points for Injection Molding

Process Core: Low-shear staged filling, two-stage low-pressure holding, and adequate, balanced cooling to minimize internal stress and enhance outdoor impact resistance and weatherability.

Zoned Barrel Temperature Control

ASA body shells: 175–205°C (nozzle ≤210°C); excessive heat degrades UV-resistant additives, leading to future yellowing.

ABS/PC instrument housings: 190–250°C (max 260°C); overheating releases volatile substances, causing strong odors in the vehicle interior.

Modified PP battery compartments: 190–220°C; flame-retardant ABS electronic control housings: ≤225°C (excessive heat compromises the flame-retardant system).

Staged Variable-Speed Filling

Large protective panels utilize a three-stage speed profile: low-speed buffering at the gate, medium-to-high speed for the intermediate filling phase, and reduced speed for venting at distant weld lines to minimize shear-induced internal stress. Glass-fiber reinforced parts are molded at medium-to-low speeds throughout to mitigate "fiber floating" defects. Injection pressure is set at 90–120 bar; insufficient pressure results in weak weld lines prone to fracture from vehicle vibration, while excessive pressure causes flash and internal stress accumulation, leading to cracking during thermal cycling.

Two-Stage Holding Pressure

PP and glass-fiber reinforced PP are semi-crystalline materials with high shrinkage rates; therefore, a two-stage holding pressure profile is implemented to ensure adequate material compensation. Holding times are set at 6–10 seconds for thin-walled cosmetic parts and 15–20 seconds for thick-walled battery compartment brackets to eliminate surface sink marks; holding and material plasticization occur simultaneously to shorten the molding cycle.

Cooling and Part Removal Protocols

Cooling time is calculated at 3–5 seconds per 1 mm of wall thickness (e.g., 9–14 seconds for a 2 mm thick housing). Insufficient cooling compromises part flatness upon demolding, leading to ongoing shrinkage and deformation during storage or outdoor use, which causes misalignment during vehicle assembly. Mold opening and ejection proceed at low, steady speeds; a robotic arm handles part removal, and manual contact with cosmetic surfaces is strictly prohibited to prevent oil contamination from affecting paint adhesion. After removal, parts are laid flat on fixtures; stacking or compressing hot housings is forbidden.

IV. Post-Processing: Shaping and Stress Relief

Precision Trimming of Gate Burrs

Large cold-runner gates are removed smoothly using hydraulic cutters, while fine flash on the parting line is ground down with pneumatic precision grinding heads. Diamond grinding heads are used for rigid glass-fiber-reinforced parts to ensure burr-free, tight-fitting assembly and prevent stress-induced cracking caused by vehicle vibration.

Annealing for Stress Relief (Mandatory for Painted Parts)

All ASA and ABS/PC housings destined for painting or baking undergo constant-temperature annealing in an oven at 60–70°C for 2–3 hours. Slow cooling releases internal stresses, preventing cracks during the painting/baking process or due to outdoor temperature fluctuations. Slightly warped guards and fenders undergo low-temperature thermal shaping in dedicated metal fixtures to ensure uniform gaps across the vehicle.

Surface Pre-treatment

Painted parts undergo electrostatic dust removal and plasma degreasing to eliminate mold release agent residues and enhance paint film adhesion. Transparent PC light housings receive UV hardening treatment to resist scratches from stones. Flame-retardant electrical control components undergo random sampling for insulation and flame-retardancy testing before being approved for warehousing.

We are a aoto car plastic body parts moulding manufacturer, providing high-quality aoto car plastic body parts moulding manufacturing. As long as you want to customize/develop aoto car plastic body parts moulding products, you can find us. We have professional injection mold design and mature manufacturing technology, providing you with one-stop service, from product design-mold making-product production-product packaging-product transportation, we can help you in every link. As long as you come to us, we will provide you with the ultimate service and satisfy you in terms of product quality, production time, information dialogue, etc.

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We are Custom Plastic Mold factory. Our factory is plastic injection mold maker. we has 17 years of experience in professional custom plastic mold and 10 years of foreign trade experience. We are custom Plastic Mold supplier. We can provide custom Plastic Mold service. Our factory can make the Injection molded plastic parts, and the quality of the products will satisfy you.

We have more than 50 high-end machines and hundreds of engineers and designers. We can provide one-stop service, from product design - mold making - product production - product packaging - transportation. We have a complete production chain. We can meet all your requirements.

Services we provide:

Professional custom mold service, Plastic mold design and manufacturing .plastic product production, product design, mold design, blow mold customization, rotational mold customization, die-casting mold customization. 3D printing services, CNC manufacturing services, product packaging, customized packaging, shipping services.

We always adhere to the principles of quality first and time first. While providing customers with the highest quality products, try to maximize the production efficiency and shorten production time. We are proud to tell every customer that our company has not lost any customer since its establishment.If there is a problem with the product, we will seek a solution actively and take responsibility to the end.

FAQ

Q1: Are you trading company or manufacturer ?

A: We are manufacturers.

Q2. When can I get the quotation?

A: We usually quote within 2 days after we get your inquiry.

If you are very urgent, please call us or tell us in your email so that we can quote for you first.

Q3. How long is the lead-time for mold?

A: It all depends on the products' size and complexity. Normally, the lead time is 25 days.

Q4. I have no 3D drawing, how should I start the new project?

A: You can supply us a molding sample, we will help you finish the 3D drawing design.

Q5. Before shipment, how to make sure the products quality?

A: If you don't come to our factory and also don't have the third party for inspection, we will be as your inspection worker.

We will supply you a video for production process detail include process report, products size structure and surface detail, packing detail and so on.

Q6. What is your payment terms?

A: Mold Payment: 40% deposit by T/T in advance, 30% second mold payment before sending out the first trial samples, 30% mold balance after you agree the final samples.

B:Production Payment: 50% deposit in advance, 50% before sending out the final goods.

Q7: How do you make our business long-term and good relationship?

A:1. We keep good quality and competitive price to ensure our customers benefit for best quality products.

2. We respect every customer as our friend and we sincerely do business and make friends with them, no matter where they come from.