Closure ovality / out-of-round
Cause
Uneven cooling or ejection stress deforms the closure, breaking the seal.
Corrective action
Balance mold cooling, optimize ejection, check post-mold handling and storage temperature.
Diagnosis guide: Deformation (out-of-round, warped, ovality)
What you will see
Closure is not circular — OD measured at two perpendicular axes differs by >0.15 mm. STATION 01 + STATION 04 (top view, tamper band) IMD catches this. Symptoms downstream: cocked application, intermittent torque drop on the capping line, partial seal engagement.
Likely causes
- Cooling time too short at Delta IM line (ejected before full crystallization)
- Mold cooling channel partial blockage (one half cools slower)
- Storage stacking pressure (warpage in lower cartons under load)
- Hot storage (>40°C ambient exposure)
Do this first
Measure OD at two axes with vernier calipers on 30 closures. Flag any with >0.15 mm difference.
How to diagnose it
- Sample 30 closures from middle and bottom of carton
- Measure OD at 0° and 90° on each
- Record max ovality value; compare to SKU spec sheet tolerance
- Check storage history (carton stacked >5 high? exposed to heat?)
How to fix it
- Quarantine cartons from bottom of pallet (stacking-induced warpage)
- Sort cartons by lot date; warped lots return to Delta for credit
- Adjust storage: max 4 cartons high; pallet stretchwrap; temperature-controlled