Exploring the drilling behaviour of cold-sprayed hybrid metal-FRP structures: an experimental investigation

This research work aims to study the drilling behaviour of hybrid composite structures made of glass fibre-reinforced polymer matrix metallised with a surface aluminium layer produced via cold spray technology. The metal deposition creating the coating was optimised by applying a thermoplastic layer to the thermoset composite structure using the co-curing technique. Aiming to highlight the influence of the metallic coating on the workpiece’s response during drilling, this research systematically analyses the effects of drilling parameters such as feed rate and spindle speed on delamination, burr formation and hole quality. In-process monitoring techniques, including thermocouple temperature and thrust force measurements, as well as energy consumption estimation, were utilised to evaluate drilling performance. The main findings demonstrate that selecting the composite side as the inlet surface results in the highest measured force and reduced delamination, meaning that aluminium coatings significantly impact drilling dynamics.