Ultrasonically assisted drilling of aerospace CFRP/Ti stacks

Structural application involving aerospace stacks consisting of carbon-fiber-reinforced plastics (CFRP) and metals (such as aluminium and titanium) are characterized by their superior mechanical properties and relative ease of design. In many of such applications, drilling is required for hole making to facilitate fasteners for assembly. However, drilling with conventional methods pose several well-documented challenges including a requirement of an additional step for de-burring, increased tool wear, damage in the composite phase etc. Ultrasonically assisted drilling (UAD) is a hybrid machining technique, which has proven to enhance drilling quality in hard-to-machine materials. In this paper, UAD of stacks is implemented demonstrating significant improvement in hole quality produced in aerospace CFRP/Ti study with reduced drilling forces and energy spent.