Rheological Variance and Gel Contamination in House Blended Compounds
House blending recycled resins causes melt viscosity drift and crosslinked gel contamination that disrupts mold filling and degrades part mechanical strength.
Optical Particle Counting
Meaning
Light-based measurement defines the methodology used to detect, categorize, and quantify microscopic contaminants suspended in a fluid or on a surface. Quality control laboratories rely on optical particle counting to monitor the purity of polymer pellets and liquid additives before moulding begins. This measurement detects gel particles, dust, and metallic debris that can degrade the mechanical and optical properties of finished parts, particularly in high-precision lenses or light guides.
Defect Prevention
Unwanted particulates in the resin melt can clog hot runner nozzles and cause surface blemishes in thin-walled mouldings. When factories use optical particle counting on incoming plastic resins, they can reject contaminated lots before they reach the hopper. This inspection saves hours of machine downtime and prevents the production of scrap.
Sourcing Influence
High-performance polymers used in medical devices must meet strict purity standards. Virgin resins typically display low particle counts, while regrind resins show higher levels of contamination from handling. Documenting these values helps moulders choose the appropriate material for critical applications.
Process Adaptation
Engineers adjust the filtration screen packs in extrusion and injection lines based on the measured contaminant levels. If the count of large particles rises, installing finer mesh screens prevents these impurities from reaching the mould cavity. This simple adjustment ensures the structural integrity of the moulded parts.