Preliminary study of the dry drilling process of CFRP/UNS A92024 stacks held together by adhesives

Currently Airship Building Industry (ABI) applies new developments of materials by stacking classics (as light alloys) and more recent (such as Carbon Fiber Reinforced Plastics) on different structural elements in order to improve the performance of the aircraft. Stacks have been usually formed by mechanical union although it provokes a weight increase. Because of this, adhesive joints have been proposed. However, this implies a third type of material, which is especially relevant in the drilling process required previously to the assembly procedure. High Performance Drilling (HPD) requires a good approximation to One Shot Drilling (OSD) and it can be affected by the presence of the adhesive in the interface CFRP-Metal, which can cause an increase of the drill defects. In this contribution, a preliminary study of the One Shot Dry Drilling (OSDD) Process of Adhesive Bound CFRP/UNS A92024 hybrid stacks have been achieved on the basis of the analysis of microgeometrical and dimensional deviations as a function of the cutting parameters applied (cutting speed and feed).