Tool wear and hole quality in drilling of CFRP/AA7075 stacks with DLC and nanocomposite TiA1N coated tools

摘要

Drilling of-multi-material stacks, constituted by two laminates in carbon fiber reinforced plastic and a core plate in AA7075, was widely investigated. Experiments were performed on a 5-axis CNC machining center, equipped with a dynamometer for the thrust force measurement, using different twist drills coated with DLC and nanocomposite TiA1N. Each hole, 6.8 mm in diameter, was obtained with a chip removal cycle involving two passes spaced by a back motion. Optical and scanning electron microscopy techniques were used to quantify tool wear and delamination of composite layers. Finally, hole diameter in the different layers of composite/aluminum stack was measured by means of a coordinate measuring machine.