1. Machine Setup and Operation Incorrect mold temperature Too much final blow pressure Bottom plate setting too high or too low - bottle dropping or lifting when mold opens Vent holes blocked   1. Machine Setup and Operation Adjust mold cooling Reduce final blow pressure Adjust the bottom plates so that bottle stays steady when mold opens Clean vent holes Swab letters lightly   2. Mold Equipment Check relief in lettering Engraving should be relieved Shape of engraving does not correspond to clearance requirement for mold opening Poor mold material Letters are dirty or too deep   2. Mold Equipment Letters should be relieved correctly Engraving should be relieved Engraving should have clearance for mold opening Use best grade cast iron Ensure letters are clean and not too deep