Laser-assisted automated tape placement (LATP) in-situ consolidation of thermoplastic composites offers an efficient solution for production of large, high performance composite structures. The present work investigates laser repass treatment as a method of enhancing surface roughness and mechanical properties of LATP processed CF/PEEK laminates. Three laminate stacking sequences were studied, viz. [0°]₁₆, [−45°/0°/45°/90°]_2s and [±45°]_4s. Four repass treatments were performed, including single, double, perpendicular and tool-side repasses. The effect of these repasses on interlaminar shear strength (ILSS), open-hole compression (OHC), in-plane shear (IPS), density, fibre volume fraction, void content and surface roughness was investigated. Surface roughness tests confirmed the improvement of the surface finish due to repass treatment. However, insignificant differences in ILSS values were observed across all repass treatments, but a single laser repass did appear to improve the OHC and IPS performance. Autoclave treated samples were used as a benchmark to compare with LATP processed laminate properties.

A critically important consideration of stiffened structural panels is the interfacial properties between skin and stiffener. In the present study a novel implementation of laser-assisted tape placement (LATP) was used to produce a representative skin-stiffener of a wingbox from carbon fibre reinforced PEEK. First, a stiffener is manufactured using this method and subsequently the skin is attached using the same method without need for a secondary bonding process. The interfacial properties between the skin and stiffener have been characterised in terms of interlaminar shear strength (ILSS) and fracture toughness (Mode-I and Mode-II) properties. LATP laydown direction and laser power was found to influence the skin-stiffener interface Mode-I fracture toughness, but not affect the Mode-II fracture toughness. The values of ILSS and fracture toughness compare favourably with those results reported in the literature, in particular for those reported for equivalent aerospace certified CF/PEEK material (APC-2).