Abstract

Thermostamping is a popular manufacturing method to form thermoplastic composites because of its fast cycle time, allowing production at low cost. As any manufacturing method, obtaining a defect-free part which respects the geometry tolerance is a challenge.
The goal of this study is to use simulations to evaluate and optimize the manufacturing process of thermostamped parts in order to avoid or minimize defects. The defects analyzed here are shape distortions and wrinkles. In addition, a cost analysis method is developed to estimate composite manufacturing costs.
A detailed characterization of PPS/Carbon pre-impregnated material in order to identify the specific heat, the coefficient of thermal expansion and the mechanical properties over a wide range of temperature was conducted. Those temperature related properties are then used in a finite element analysis using a sequential thermal-mechanical approach to predict shape distortion. The model is evaluated for spring-in of an angled part. A sensitivity analysis showed that CTE is the most influential parameter compared to the friction coefficient and mechanical properties.
A methodology to optimize the initial manufacturing set-up and to minimize or to remove wrinkles using different methods is done using a commercial finite element software. It was found that removing redundant material, adding springs and changing springs tension are successful methods to eliminate wrinkles in a double curved part manufactured with thermostamping.
Finally, a cost analysis methodology is presented. The method is applied to a case study comparing thermostamping of long fiber reinforced thermoplastics, resin transfer molding of a thermoset with long fiber and compression molding using short fibers.