Use of thermoplastics in composite structures has a long history of frustration, but a new project takes an interesting approach in an ongoing effort to boost cycle times and performance of parts for aerospace and automotive applications.
A Dutch consortium called the Thermoplastic Composites Research Center (TPRC) is leading an effort to advance the overmolding process for thermoplastic composites.
Overmolding combines press forming of thermoplastic composites and subsequent injection overmolding, creating net-shape stiff and strong parts with a high level of function integration. Thermoplastic composites feature excellent mechanical properties and low weight. Overmolding combines the best of traditional composite production with the speed and ability to design complex shapes of the injection molding process.
The research focus is on interface weld strength and warpage.
The consortium includes OEMs (Boeing), tiers (Safran Composites, Fokker Aerostructures, SMP, Johnson Controls, DTC, Daher, Harper Engineering), material suppliers (Victrex, TenCate), equipment suppliers (KraussMaffei), software companies (Autodesk, AniForm), as well as academic groups (University of Twente, Saxion).
“The demand for new engines as a result of the strong growth of air traffic represents industrial challenges to Safran,” says Wouter Balk, R&D project engineering, SAFRAN. “With regards to composite engine components we are therefore actively looking for innovative processes enabling reduced cycle time and cost. We expect thermoplastics and overmolding to be a suitable solution for some specific engine parts.”
KraussMaffei is making a state-of-the-art research injection molding machine available for the project. KM hopes its involvement will lead to greater penetration of the aerospace market.
In 2008, Boeing, TenCate Advanced Composites, Fokker Aerostructures and the University of Twente first began collaborating on two joint research projects that involve materials used in thermoplastic composites, as well as joining and bonding methods.