The effect of cutting parameter changeover position on interface borehole quality in drilling of aerospace CFRP/Al stacks

Drilling multi-material aerospace stacks (e.g. CFRP/Aluminum) at the interface region represents the most challenging phase of the drilling cycle due to bi-material engagement of the cutting edges. This research investigates the impact of several drilling strategies on interface borehole quality, to allow for a fundamental understanding of the machining process taking place at the stack interface. In the experiments, cutting parameters were changed over from one workpiece material layer to the next at different positions relative to the interface, and the resultant impact on interface borehole quality was assessed based on borehole diameter, composite surface damage and interlayer burr height.