The molds prepared in the 1989 and the 1990 studies are used to compare the effects of injection pressure in relation to shrinkage factors. In the study a set of measurement parameters were developed for an accurate comparison of the wax patterns made with a variety of wax injection pressures.

The measurements show that a variety of wax measurements can be obtained by using different injection pressures on any given mold compound. Different mold compounds will yield different ranges of measurement depending on the durometer of the mold compound. In this study we find that the molds made with the plunger type frames and the “pre-made” type mold compounds yield measurements similar to the measurements given by the RTV mold compounds.

Graphs were developed to show the variations in the measurements taken in this study. The width, thickness and wax weight measurements are illustrated in the graphs and compared to the model measurements. The graphs show both actual measurement as well as the measurement as a percentage.

Authors: Louis Sanchez, Walter Judge