One of the biggest challenges in designing injection molded parts is optimizing the design to control volumetric shrinkage differences to result in minimal part warpage. Part design, mold design, polymer material, and the molding process are interdependent, so understanding how each one affects the others is important for a successful outcome. In this lesson we will focus on the impact of amorphous versus semi-crystalline materials on shrinkage and warpage behaviors.
Topic in this lesson include: a review of the differences between amorphous and semi-crystalline materials, how to predict shrinkage behaviors of different materials by using PVT curves, how to understand temperature and pressure behavior using PVT graphs, how different materials and gate locations impact injection pressure, clamp tonnage, volumetric shrinkages, and linear shrinkages, and how different materials impact part warpage and flatness.
