Injection Molding
3 Aufrufe
PP Tiger Stripe (Flow Mark)
Problembeschreibung
Alternating light-dark tiger-stripe patterns appear on large-area PP parts such as automotive bumpers and door panels.
Ursachenanalyse
In impact copolymer PP, the rubber phase and matrix fluctuate in distribution under filling shear, forming periodic gloss differences; injection speed fluctuation and improper gate design can induce it.
Lösung
①Optimize the injection speed profile to maintain a stable front; ②raise mold temperature and melt temperature; ③enlarge the gate to reduce shear fluctuation; ④if necessary, switch to anti-tiger-stripe grades.
Wichtigste Erkenntnis
Tiger stripes are flow imprints of rubber phase distribution—stable speed is the core.
War das hilfreich?
0 Personen fanden dies hilfreich
Vielen Dank für Ihr Feedback!