Finite Element Modeling of Drilling Processes with Solid and Indexable Tooling in Metals and Stack-ups

Automotive drilling operations generally entail threaded fasteners loaded in tension in steel and cast iron workpiece materials, while aerospace applications focus on holes for rivets loaded in shear in aluminum, titanium and composite stack-ups. Optimal chip flow and tool life are often in competition with burr formation, general hole quality and cycle time. Physics-based modeling of drilling processes can provide insight and information not readily available or easily obtained from experiments, and in a much faster time frame. A three-dimensional finite element-based model of drilling is presented which includes fully adaptive unstructured meshing, tight thermo-mechanical coupling, deformable tool-chip-workpiece contact, interfacial heat transfer across the tool-chip boundary, and constitutive models appropriate for high strain-rate, large strain and high temperature deformation. Explicit modeling of entrance, steady-state and exit modeling of aluminum and titanium materials, as well as metal stack-ups is performed. Drilling through stack-up layers is also shown. The modeling includes both solid twist and indexable drills. Metal cutting tests are performed and comparison with predicted data is provided.