1. Feeder
  • Temperature of the glass is uneven and usually too hot
  • Gob is too pointed 
1. Feeder
  • Set temperature of forehearth so that the gob does not curl
  • Adjust gob shape

 
2. Machine Setup and Operation
  • Counterblow air on too soon (insufficient plunger reheat time).
  • Counterblow air on too late (too much plunger reheat time and glass too hot)
  • Too much cooling on the plunger (blow and blow)
  • Plunger contact time too long, chilling the glass
  • Too much oil or dope on the neck ring
  • Uneven blank cooling (blow and blow)
  • Blanks hot and dry
  • Dirty plunger or neck ring
  • Plunger receiver too high-trapping gas
  • Counter blow valve sticking
  • Vacuum not coming on
  • Funnel too large. Drop hanging up on foot of blank

 
2. Machine Setup and Operation
  • Retard the counterblow
  • Advance counterblow and cool the glass
  • Reduce plunger cooling air
  • Reduce plunger contact time
  • Fit drip pan to the deflector
  • Balance the cooling air on the two mold halves
  • Increase blank cooling and swab as required
  • Change plunger and/or neck ring

 
3. Mold Equipment
  • Incorrect plunger design
  • Take-out tongs too small

 
3. Mold Equipment
  • Adjust plunger design
  • Correct size of take-out tongs
  • Take .002 increments from nose of plunger

 

Note: Bottles are usually filled using filling tubes. If the bore of the neck is too small, the filling tube will jam and either break itself or the bottle. This will jam the filling line and cause loss of production