1. Feeder
  • Glass too hot
1. Feeder
  • Reduce the glass temperature

 
2. Machine Setup and Operation
  • Plunger to too hot (press and blow operation)
  • Plunger dirty (press and blow process)
  • Plunger adapter has become loose
  • Restriction of the cooling and/or exhaust air (plunger cooling)
  • Partially formed birdswing

 
2. Machine Setup and Operation
  • Correct cooling air to plunger for timing and pressure
  • Change the plunger
  • Plunger adaptor must be tight on the piston rod
  • Use larger exhaust hold
3. Mold Equipment
  • Incorrectly designed plunger cooling tube and adaptor
  • Poor type of plunger material
3. Mold Equipment
  • Check design of plunger cooling adaptor and tube
  • Change plunger material

 

Note: The effect of a spike can be produced by a glass particle falling or being blown into a hot container and sticking to the body of the container. Good housekeeping is required to remove all possible particles from the machine.