Auto Plastic Manufacturing: Core Molding Processes

Amid the trend of automotive lightweighting and personalization, plastic parts manufacturing plays a key role in optimizing vehicle performance. Injection molding and blow molding, with their mature technical features, are core to automotive plastic production, covering the manufacturing of interior, exterior and functional components.

Injection Molding: Mainstay for High-Precision Molding

Injection molding follows the core process of "plasticization-injection-solidification", achieving high-precision production through precise parameter control. Hygroscopic materials like PA and PC need drying at 80-120℃ for 2-4 hours to keep moisture below 0.2%. With gradient heating for plasticization, molten material is injected at 50-150MPa, followed by pressure holding to ensure ±0.5mm precision. Cooling takes 50%-70% of the cycle.

Its advantages include high precision for complex structures, uniform strength, and efficient mass production. It is used for dashboards, center consoles, bumpers and grilles. For example, bumpers are made of PP+EPDM via injection molding for impact resistance and design flexibility.

Blow Molding: Efficient Solution for Hollow Parts

Blow molding, designed for hollow parts, involves parison forming, inflation molding and cooling. Extrusion or injection produces tubular parisons, which are then inflated with compressed air to fit mold cavities.

It boasts low cost (15%-20% lower unit cost for mass production) and good adaptability for irregular spaces. HDPE fuel tanks, air intake pipes and armrest box liners are typical blow-molded products, offering light weight and corrosion resistance.

Auxiliary Processes & Conclusion

Auxiliary processes like gas-assisted injection molding (5-30MPa nitrogen, 10%-20% weight reduction), two-color injection molding and insert molding expand manufacturing possibilities.

Injection and blow molding meet diverse needs for automotive plastics. As new energy vehicles demand more lightweight and integrated parts, these processes will continue to advance with technological optimization.