Meaning
Recycled thermoplastic resins sourced from manufacturing scrap and sprues of polyamide 66 processes undergo re-granulation to be used again in moulding applications. Known as post-industrial rPA66, this material offers a more consistent quality and lower risk of contamination than post-consumer regrind. Its utilization is limited by the loss of physical properties that occurs with each heating cycle due to thermal degradation.
Material Composition
Manufacturing scraps such as runners and flash are collected directly from the production floor, sorted by grade, and ground into flakes or re-extruded into pellets. This material exhibits high tensile strength and thermal stability, but it suffers from a reduced molecular weight and lower viscosity compared to virgin resin. To maintain processability and mechanical performance, molders often blend it with virgin polyamide 66 in specified ratios, usually between ten and thirty percent.
This practice allows for cost reductions and footprint improvements without sacrificing the mechanical integrity of the molded parts.
Moulding Challenge
The increased flowability of the lower-viscosity recycled resin can lead to flash at the tool parting lines if injection pressure is not managed carefully. Hygroscopic behavior remains high, so the material must be dried to below 0.15 percent moisture before molding to prevent hydrolytic degradation. Failure to dry the resin results in splay and brittle parts.
Quality Verification
Because post-industrial sources are well-tracked, the material’s history is generally known, but testing is still necessary to ensure consistent batch-to-batch flow behavior. Melt flow index measurements and moisture analysis are conducted on incoming batches to adjust the process settings of the injection moulding machines. This testing helps stabilize the moulding window and ensures that the finished parts meet the required tensile specifications.
