Virgin Resin Specification Gaps and Undeclared Regrind Content
Undeclared regrind in virgin polymer collapses oxidation stability and broadens viscosity bands, increasing landed cost per good part despite initial pellet discounts.
Process Scrap
Meaning
Polymer waste generated during production operations represents unmarketable material that has undergone primary processing without reaching end-use customer delivery. Manufacturing plants classify sprues, runners, edge trims, and off-specification parts as process scrap during internal inventory control tracking. The material retains known chemical formulation history, allowing controlled grinding and reintroduction into production streams.
Scope includes clean internal industrial reclaim, ending where cross-contamination or extreme thermal degradation renders the material unusable.
Generation Source
Cold runner injection moulds convert a significant fraction of each shot into solid feed channels that must be trimmed from parts. Extrusion blow moulding generates flash around part perimeter seams during tool closure. Startup operations and color transitions generate contaminated melt volumes until steady-state processing resumes.
Quality Contamination
Repeated thermal history degrades molecular weight and reduces stabilizer reserves within regrind material. Dust and fine particles produced during granulation cause inconsistent melting inside the extruder barrel. Floor contamination and mixed polymer types create incompatibility defects that reduce mechanical strength.
Economic Penalty
Re-granulating clean scrap reduces virgin resin consumption and lowers overall part material costs. Moulders set strict blend limits to ensure regrind additions do not compromise part dimensions or physical properties. Dedicated granulators positioned beside injection presses minimize transport handling and airborne dust accumulation.