Heating the glass wafer until the moulding temperature is the first important step in the glass moulding process and any reduction in time of this heating stage increases the production efficiency, considerably. Depending on the requirements for heating time and temperature uniformity in the glass wafer, heating can be performed by either conduction or radiation. The numerical simulation of these two heating mechanisms in the wafer based glass moulding process is the topic of the present paper. First, the transient heating of the glass wafer is simulated by the FEM software ABAQUS. Temperature dependent material data of the glass wafer are taken into account in the simulation to have a more realistic model of the material. Heating curves depicting temperature as a function of time inside the glass wafer are predicted for both radiation and conduction heating and based on that the heating time and the temperature uniformity in the glass wafer are evaluated for both heating mechanisms. Subsequently, the approximate radiation heat loss from the glass wafer during cooling is calculated using both numerical and analytical methods and the temperature change in the glass wafer versus time is obtained for this stage. The achieved results make way for an increased understanding of the heating process in precision glass moulding and hence a possible improvement of the heating system.
Proceedings of the 12th Euspen International Conference, 2012