← Defect Guide
Silver Streak
Silver or streaky lines running in the flow direction from the gate, caused by moisture or gas.
◆ Common Causes
- •Insufficient resin drying (moisture)
- •Melt temperature too high (decomposition gas)
- •Air entrapment (back pressure too low)
- •Check ring backflow
- •Release agent outgassing
◆ Solutions
- ✓Verify drying temperature and time
- ✓Lower melt temperature
- ✓Increase back pressure
- ✓Reduce screw RPM
- ✓Reduce 1st-stage injection speed
◆ Resin-Specific Notes
PA66
Strong moisture absorption. Drying mandatory (80°C, 4–8 hrs).
PA6
Dry at 80°C, 4–6 hrs.
PA46
Extremely hygroscopic. Dry at 80°C, 16–24 hrs.
PC
Dry at 120°C, 4 hrs. Re-drying is essential.
PMMA
Dry at 80°C, 3 hrs.
TPU
Dry at 80–100°C, 2–4 hrs.
PBT
Dry at 120°C, 4 hrs.
◆ Resins Prone to This Defect
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This content is a field-reference summary. Final judgment requires on-site engineer verification.