Preform haze / cloudiness
Cause
Insufficient drying (moisture) or crystallization from slow cooling causes haze.
Corrective action
Dry resin to <50 ppm moisture, dew point -40°C; check chiller/mold cooling; verify hot-runner balance.
Diagnosis guide: Preform hazy / cloudy appearance
What you will see
Preform appears cloudy or hazy rather than clear. Caused by moisture-induced hydrolysis during injection molding. Bottles will be hazy and structurally weakened.
Likely causes
- Resin not dried sufficiently before IM at Delta plant (dewpoint >−40°C)
- Wet PET pellets at Delta
Do this first
STOP receiving. Hazy preforms produce structurally weak bottles.
How to diagnose it
- Hold preform up to light against dark background
- Clear preform: transmits light clearly
- Hazy preform: milky / cloudy transmission
- Photograph for Delta reference
How to fix it
- Quarantine entire lot
- Contact Delta immediately with photos + lot number
- Request full lot replacement under quality guarantee