Abstract
A typical stage in the manufacturing of container glass, such as bottles and jars, is the pressing phase. At this stage a gob of hot glass (1000° C or higher) is pressed in a mechanical construction. Various aspects of this process can be investigated with respect to mathematical modeling and numerical simulation. This paper describes an important part of the process, the motion of the plunger. The problem is to determine the velocity of the latter which appears as a (kinematic) boundary condition of the glass flow problem. We show how to effectively uncouple these and to solve the resulting stiff differential equation numerically.