Ultrasonic welding of CF/epoxy to CF/PEEK composites

Effect of the energy director material on the welding process

Conference paper (2020)

Authors

E. Tsiangou Aerospace Manufacturing Technologies - Aerospace Engineering
S. Teixeira De Freitas Structural Integrity & Composites - Aerospace Engineering
I.F. Villegas Aerospace Manufacturing Technologies - Aerospace Engineering
R. Benedictus Structural Integrity & Composites - Aerospace Engineering
Research Group
Aerospace Manufacturing Technologies (Aerospace Engineering) (TU Delft)
Copyright: © 2020 E. Tsiangou, S. Teixeira De Freitas, I.F. Villegas, R. Benedictus
Composites Ultrasonic welding Thermoplastics Thermosets Energy director
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Published Date

2020

Language

English

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Faculty

Aerospace Engineering

Department

Aerospace Structures & Materials

Research Group

Aerospace Manufacturing Technologies

Abstract

With its short heating times, ultrasonic welding is a highly promising technique for joining thermoplastic (TPC) to thermoset (TSC) composites, to prevent thermal degradation of the thermoset adherend. A neat thermoplastic coupling layer is co-cured on the surface to be welded to make the TSC “weldable”. For welding CF/PEEK to a TSC adherend, it would be logical to use PEEK as the coupling layer. However PEEK and epoxy are not miscible with each other, therefore a bond created after co-curing of these two materials is not reliable. PEI on the other hand is known to be miscible to most epoxy systems at high temperatures and PEEK polymers, hence it is an excellent candidate for the coupling layer material. The other necessary element for ultrasonic welding is the energy director (ED), a neat TP film placed at the interface to help promote heat generation through preferential frictional and viscoelastic heating. Usually EDs are made from the same material as the TP matrix, but in this case ED can be either PEI or PEEK. Mechanical testing and fractographic analysis showed that the usage of a PEEK ED is the most successful approach. This research is part of the European project EFFICOMP.