The polymer molecular chain length of the plastic is one of the key variables that determines its properties The molding process, if not done properly, has the potential to break the chains that existed before molding thereby reducing properties The length of fiber additives such as glass, carbon or steel will also significantly affect physical properties Again, the molding process if not done properly has the potential to break these fibers thereby reducing properties. We find engineers are constantly struggling with the fact that their designs do not meet the performance specifications predicted in their finite element analysis and simulation models. Often engineers look in every direction searching for solutions—the material supplier, the simulation software, the assembly parameters to name a few—without properly focusing on the science of the material and the implications of the drying and molding process.