Processing and product performance

Abstract

A fundamental aspect of producing thermoplastic products is the relationship between the process and the properties and performance in service. In this chapter, a review is made of the two major processing effects in the products: the dimensional variation associated with shrinkage and the property anisotropy caused by the flow-induced molecular orientation. The shrinkage is analyzed having in sight the process variables that directly influence it and its relevance in predicting the product dimensional tolerances. The role of orientation on the properties, buildup of residual stresses and dimensional instability is put in perspective of the product quality. The issue of the ductile-fragile transition in many product failures is introduced in detail having in mind the multiple factors that are associated. Finally, a list of product failures is presented with evidence of the causes that led to them and brief reference to the analysis techniques that were used to understand them.