Extrusion & Post
2 Aufrufe
PA6 Material Change Purging Specification
Problembeschreibung
After material change, the product shows color mixing, delamination and black specks, and repeated purging is still not thorough
Ursachenanalyse
PA6 viscosity is low; during purging it easily slips in layers against high-viscosity residual material, resulting in poor purging efficiency; during shutdown PA6 cools and solidifies in the barrel, and at restart the cold material mixes in and forms defects
Lösung
①Use high-viscosity material such as HDPE or PP to flush and displace at low speed; ②Keep low speed during flushing to avoid nylon retention and isolation; ③Empty the barrel before shutdown; after adjustment, continuously sample to verify the effect, and resume mass production only after confirming stability
Wichtigste Erkenntnis
PA6 purging relies on the mechanical pushing action of high-viscosity material; low-speed flushing plus shutdown emptying is the standard procedure to avoid cross-contamination; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent recurrence
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