Ultrasonic welding of thermoplastic composites: A comparison between polyetheretherketone and low-melt polyaryletherketone as resin in the adherends and energy directors
Camila Belo Gomes Brito, Julie Teuwen, Clemens Dransfeld, Irene Fernández Villegas
Abstract
Our aim with this work was to evaluate how the thermoplastic resin used in the composite adherends and on the energy director affected the static ultrasonic welding process in both parallel and misaligned configurations. Polyetheretherketone (PEEK) and low-melt polyaryletherketone (LMPAEK) were the resins used and their thermomechanical properties were characterized via dynamic-mechanical analysis and modulated differential scanning calorimetry. With parallel adherends, neither the welding time nor the through-thickness heating in the adherends vary significantly. This similarity was attributed to a larger heat capacity of the PEEK energy director counterbalancing its higher viscoelastic heating rate. With misaligned adherends, the welding time was larger for PEEK welds than for LMPAEK welds and LMPAEK adherends presented a larger though-thickness heating. These effects were attributed to the larger bulk viscoelastic heating rate of carbon fibre reinforced/LMPAEK adherends adding up to the lower heat capacity of LMPAEK. • Ultrasonic welding of composites can be applied to different thermoplastic resins. • Different loss modulus and heat capacity affect ultrasonic welding of composites. • The degree of crystallinity of the resin indirectly affects the ultrasonic welding process. • Parallel adherends are less affected by the resin type than misaligned adherends. • Adherends fibre volume fraction affects ultrasonic welding of misaligned adherends.