Non-destructive evaluation of 3D printed materials using air-coupled ultrasonic technique

3D printing for prototyping and component production has grown increasingly popular in recent years due to the improvement of available printers and cost reductions. One of the most widely used technologies is FDM (Fused Deposition Modelling), which involves depositing filaments of polymeric material in overlapping layers by extruding it from a heated nozzle. This has increased the demand for characterisation of these objects to verify their proper quality. Due to the non-use of a coupling agent, this technique allows for faster analysis and is an excellent alternative to traditional immersion or contact methods. This work, therefore, aims to apply and evaluate the effectiveness of the innovative non-destructive analysis technique of air-coupled ultrasound by applying it to this type of component. Various samples differing in size, filling density, infill pattern and induced defects were 3D printed, and excited with ultrasound probes by evaluating their effect on ultrasonic propagation in the samples.