Prediction of shrinkage by dual kriging for injection molded polypropylene plaques

The shrinkage of thermoplastic products has become an important theme of investigation for many researchers during the last two decades. Two approaches have been followed. The first one consists of solving the balance equations (mass, momentum, and energy) that govern the polymer flow and cooling. The shrinkage and warpage of the part are then deduced from this solution. The second approach is empirical and consists of fitting a model to experimental data. In this article, a new empirical method of prediction, based on dual kriging interpolation, is proposed. A theoretical validation is performed on a set of experimental measurements. The results are compared with previous models based on regression, which can be obtained as limit cases of dual kriging.