Mapping technological advances in drilling for aircraft manufacturing: a hybrid bibliometric and expert-guided review

Drilling is a pivotal operation in aircraft manufacturing, directly affecting assembly precision, fastening reliability, and structural integrity. Despite its significance, previous reviews have largely concentrated on isolated machining challenges, specific material stacks, or narrow process variables, often overlooking broader technological evolution across the aerospace drilling domain. This study addresses this gap by systematically mapping recent advances in drilling technologies for aircraft manufacturing through a hybrid review methodology that integrates bibliometric analysis, semantic topic modelling, and expert-guided taxonomy refinement. A comprehensive literature corpus was constructed and analysed to identify research theme clusters, emerging trends, and key contributors. The resulting five-theme taxonomy captures the field through: intelligent monitoring and quality analytics; hybrid stacks and multi-material drilling; process optimisation and predictive modelling; advanced hole-making processes; and damage, surface integrity, and sustainable drilling. The review reveals a clear transition from conventional parameter optimisation towards digitally enabled drilling systems characterised by in-process sensing, adaptive control, machine-learning-assisted prediction, and autonomous quality assurance. In parallel, growing research attention is directed towards hybrid material stacks, non-conventional hole-making techniques, and sustainable machining strategies to improve process robustness and manufacturing efficiency. Beyond synthesising current technological directions, this work demonstrates a replicable and scalable methodology for evidence-based research mapping in high-value manufacturing, providing a structured foundation for future aerospace drilling research and industrial implementation.