Reflectivity and emissivity analysis of thermoplastic CFRP for optimising Xenon heating and thermographic measurements

The demand for efficient composite production processes is growing as the proportion of composites in modern aircraft increases. Particularly, thermoplastic composites are interesting for sustainability and cost efficiency. They can be manufactured using deposition methods, which involve heating by radiation in the visible and near-infrared spectra. A Xenon flashlamp is a commonly used for manufacturing. In-line inspection can be performed using thermographic cameras which measure infrared radiation. For those, the composite's angle-dependent reflection and emission behaviour is interesting. Accordingly, the relationships between angle and temperature dependent visible/near-infrared reflectivity and thermal infrared emissivity is investigated and composite's conductivity properties are derived. The link between the material's optical and electromagnetic properties is estimated through the Brewster angle derived from Fresnel fitting, which allows the prediction of the directional electrical and thermal conductivity by non-contact measurement. The findings from this study will be valuable for users of Xenon heating and thermographic measurement systems.