Surface engineering strategies for aerospace composite repairs: Machining and texturation of additive manufacturing parts by abrasive waterjet

In aerospace maintenance, repair and overhaul operations, additive manufacturing (AM) holds great potential for composite repair, providing a precise and customized approach to fabricating repair patches for damaged structures and reduce waste. Given the circularity and economic advantages, repairing composite structures is often preferable to replacement. This study explores the use of abrasive waterjet process for machining and texturing AM composites composed of micro carbon infused nylon matrix and continuous carbon fiber reinforcement. Four surface conditions were investigated: (I) machined without additional surface preparation, and (II, III, IV) machined followed by three levels of texturation - good, medium, and poor. These surfaces are quantitatively evaluated based on crater volume (Cv) and arithmetic mean height (Sa). The mechanism of material removal was investigated by surface texture analysis and scanning electron microscopy. A prediction model was developed and experimentally validated for assessing the correlation of Cv and Sa. Results show an ascending trend in both Cv and Sa values from condition I to IV. The study reveals important findings on machined surface characteristics and their preparation for adhesive bonding, which are crucial for integrating repair patches onto parent structures.