Injection and blowmolding combine in the production of a resonator molded from polyamide materials. The internal (ID) section injection molded in the first step is then overmolded to form the external (OD) section via blowmolding. The resonator is used in 2012 model Ford Fusion and Escape models using the OEM's 2.0-L Ecoboost engine.
System supplier Contitech AG (Hannover, Germany) selected a 20% glass filled grade of Nylon 66 (Zytel 70G20HSLX) from DuPont Performance Polymers (Wilmington, DE) for the ID and a 35% glass filled for the OD (70G35HSLX) to become one homogenous structure upon cooling. The first prototype design for the plastic resonator used two dissimilar polymers, polyphenylene sulfide (PPS) on the ID and Zytel on the OD.
Processing was handled by Polymer Products (Grand Rapids, MI). Particular attention was required for design of the die/tooling to permit the parison to enter concentrically over the previously injection molded ID structure and remain centered in the blow molded OD upon cooling.