Meaning
The process of replacing the specified plastic raw material used in molding an enclosure with an alternative polymer can alter the mechanical and electrical properties of the finished housing. Initiating a resin substitution requires careful evaluation to ensure that the new material meets the same flammability, impact strength, and dielectric requirements. This change is often driven by material shortages or cost-reduction efforts.
The evaluation must be conducted before the new material is run in production tooling.
Material Evaluation
Dielectric properties of the polymer can affect the performance of internal antennas if the replacement material has a different permittivity. This can lead to detuning and reduced wireless range. Mechanical properties like shrinkage must also be matched to prevent parts from warping.
Certification Impact
Regulatory approvals may be invalidated if the substituted material has a lower flame rating or contains restricted substances. This means that the product may need to be re-evaluated by agencies like Underwriters Laboratories or the FCC. Documentation demonstrating compliance must be updated to reflect the new material.
If this is not done, the manufacturer risks shipping non-compliant products to the market.
Production Run
Trial runs with the new resin must be executed to determine the optimal molding parameters like temperature and injection pressure. This step ensures that the physical dimensions of the part remain within specifications. It prevents the production of scrap parts.
