Heat transfer modelling of the parison forming in glass manufacturing

Parison formation in a narrow neck press and blow process for glass container forming is studied. Heat transfer in the plunger, glass and blank mould during parison formation is analysed by a numerical model. A finite difference formulation is used for the heat transfer calculations. The transient heat transfer during the parison forming is a combination of radiation and conduction. The heat transfer from the glass to the plunger and blank mould is influenced by the contact resistance between glass and manufacturing equipment. The contact resistance is calculated as a function of plunger pressure and glass temperature. The temperature distribution in the parison after the forming process is determined mainly by the surface temperature of the blank mould and the plunger. The influence of the radiation heat flux in the glass is found to be negligible compared to the conduction heat flux. The surface temperature is affected mainly by the plunger pressure and the cooling of the manufacturing equipment. If the cooling or the pressure is changed, the temperature of the manufacturing equipment will change relatively slowly accompanied by a change in the parison temperature distribution.