The effect of feeder orfice ring orientation on gob formation was investigated using several numerical codes. Variations in gob weight between orifices were found to be due to deviations in gob temperature profiles. These deviations, due to a difference in glass residence times between orifices, were found to significantly change the viscosity distribution and manner in which the gob is formed as it flows from the feeder. Numerical models have showed that variations in gob properties between orifices can be reduced but the careful design of feeder internals. A new feeder has been developed that significantly reduced thermal variations between orifices. It has the additional benefit of reducing gob bowing, which is caused by asymmetric velocity and pressure gradients at the orifice ring.
