Effect of Electrical Augmentation on the Joining of Al6063-T5 Using Flow Drill Screws

Increasing fuel economy standards have motivated automakers to reduce vehicle mass with multi-material bodies-in-white. One joining technology particularly suited for onesided multi-material joining is Flow Drill Screwdriving (FDS), a process by which a fastener friction drills, penetrates the joint, thread-forms, and then torques to apply clamping pressure to the joint. The frictional nature of FDS induces thermal softening of the material but requires time for the heat to build. Prior work with thermal assistance has shown that increasing pre-process temperature leads directly to reducing penetration time, but may add to overall cycle time. A more efficient augmentation approach through Electrical Augmentation (EA) is investigated to reduce cycle time. An experimental investigation of the EA-FDS process is presented, with the joint metrics quantified through installation torque, process time, and breakloose torque. EA-FDS is shown to reduce cycle time, and have the ability to join thicker cross-sections.