Influence of different cooling strategies on the process temperatures and chip transport quality in one-shot drilling CFRP/Al-stacks

Abstract This study focusses on the influence of different cooling strategies on process temperatures and chip transport quality in one-shot drilling CFRP/Al-stacks. In addition to the maximum temperatures in both individual stack components, temperature changes in the CFRP material due to hot aluminium chip interactions are analysed. The following cooling strategies are compared: compressed air through the drilling tool, cryogenic CO2 cooling at the aluminium bore exit as well as the combination of both. It is shown that process temperatures and chip transport quality significantly differ for the tested cooling strategies. Whereas CO2-cooling of the Al-plate results in overall smaller chips, the use of compressed air mainly improves chip evacuation. The combination of both cooling strategies shows high potential to prevent clogging in the chip flute as well as its negative impacts on workpiece quality.