← Defect Guide
Color Streaks
Streaky or marbled color from poor pigment/masterbatch dispersion. Distinct from delamination or overall discoloration.
◆ Common Causes
- •Low back pressure → poor masterbatch dispersion
- •Insufficient screw shear/mixing (low RPM, short residence)
- •Masterbatch carrier-resin mismatch
- •Contamination with incompatible resin
- •Incorrect masterbatch ratio
◆ Solutions
- ✓Raise back pressure in steps (better mixing)
- ✓Adjust screw RPM/residence for mixing
- ✓Verify carrier-resin compatibility
- ✓Purge thoroughly; inspect material
- ✓Review masterbatch ratio and dispersibility
◆ Resin-Specific Notes
Metallic/Pearl
★ Do NOT crank back pressure — it fractures aluminum flakes, dulling and graying the finish. If the streak is angle-dependent, it is orientation, not dispersion.
GF Reinforced
Watch for fiber breakage when raising back pressure.
PP
Carrier mismatch is common. Verify masterbatch compatibility.
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This content is a field-reference summary. Final judgment requires on-site engineer verification.