An approach for predicting the correct geometry and parameters of the sprue system of an optical disc mould by use a computer aided design and simulation

3D CAD models of different variants of the sprue system design of an experimental optical disc mould are developed. The main purpose of the present work is to be predicted the correct geometry shape and parameters of the sprue system before these elements to be produced. The 3D CAD models are built as a combination of the polymer substrate and the sprue system, considered as one object. This approach allows achieving a precise design of the sprue system, before to import the 3D CAD model in the computer simulation program. Different variants of the sprue system design are defined and three parameters are chosen as variables: the gate length and depth and the sprue draft. By means of iterative steps in the frame of the mould filling simulation software, correct variants of the gate geometry and parameters and the processing conditions are achieved. The best results are obtained using the new proposed sprue system with symmetrical melt distribution area.