The goal of this lesson is to understand and evaluate PVT behavior of a molded part during the packing and cooling phase. Since material behavior depends on pressure, volume, and temperature, final volumetric shrinkage and in turn, part dimensions, are influenced by this behavior.
Topics in this lesson include: the PVT relationship and how it relates to shrinkage behavior of molded parts, understanding PVT curves, how PVT is measured, the differences in PVT measurements between amorphous and semi-crystalline materials, how packing pressure, degree of crystallinity, and volumetric shrinkages affect each other, and how process set-ups can affect packing and cooling behavior.