The number of multi-materials staking configurations for aeronautical structures is increasing. with the evolution of composite and metallic materials. For drilling the fastening holes. the processes of Vibration Assisted Drilling (VAD) expand rapidly. https://www.bekindtopets.com/flash-pick-Ovation-Toddler-Metallic-Schooler-Helmet-XXSmall-XSmall-hot-choice/