The Relationship Between Plastic Shrinkage and Part Warpage
Material shrinkage during and after manufacturing plays an important role in why injection molded plastic parts warp. The key to avoiding warpage is understanding how and why plastic materials shrink in the first place.
The key to understanding warpage with injection molded parts is understanding why plastic materials shrink in the first place. To do that, we need to start at the molecular level with a close look at what happens when plastics melt and cool.
For the most part, the melting and cooling characteristics depend on the type of polymer and whether any filler or fiber reinforcement is present.
There are three characterizations of materials with various reactions to temperature in the injection molding process: amorphous materials, semi-crystalline materials, and fiber-reinforced materials. Each demonstrates different behaviors and physical reactions to temperature that can lead to part warpage…READ MORE.