1. Feeder Glass too hot   1. Feeder Adjust the glass temperature    2. Machine Setup and Operation Machine speed too high Improper cooling wind setup or insufficient cooling wind applied Final blow pressure on after mold opens Air off 'mold close' too early Excessive final blow pressure Exhaust hole on internal cooling blow head arm too small Dirty blow molds   2. Machine Setup and Operation Reduce the machine speed Correct the cooling wind application Remove final blow before the mold open Air off 'mold close' later Reduce final blow pressure User larger exhaust hole on blow head arm Change blow molds   3. Mold Equipment Mold size too small Mold not properly vented Rough mold seams 3. Mold Equipment Use larger size mold holder Improve venting of blow mold Change molds and repair faulty seams