Comparative Analysis of Dimensional Reliability Between Amorphous and Crystalline Resins for Improving Injection-Molding Process Capability

This study investigates the effects of distinct physical properties of amorphous (PC) and crystalline (PP) resins on the injection-molding process capability and dimensional reliability of housing dry-fan components via CAE analysis and experimental verification. Simulation results indicate that whereas PC requires a high injection pressure of approximately 180 MPa, it exhibits stable dimensional behavior with a low volumetric shrinkage of 2.55%. Conversely, although PP allows for low-pressure molding at 30 MPa, it may be severely deformed owing to its high shrinkage rate of 5.23% and significant anisotropy. In actual CTQ measurements, PC demonstrates superior process capability with a Cpk of 14.02, whereas PP fails to satisfy specifications, with a Cpk of -2.20. These findings suggest that for precision-component design, mold-design compensation and process optimization considering resin crystallization characteristics should be considered instead of relying solely on material substitution for cost reduction.