Drilling of CFRP/Ti-6Al-4V Stacks
Drilling experiments of CFRP/Ti6Al4V laminated stack board were carried out use of a TiAlN-coated cemented carbide drill and a TiAlCr/TiSi-coated cemented carbide drill. In the experimental conditions described herein, tool life is longer for lowered feed speed, and a TiAlCr/TiSi-coated cemented carbide drill has longer life than the other. Additionally, the cooling performance between dry process and water-mist-cooling were compared. Regarding water-mist-cooling, although the thrust is smaller, chips are much harder. They also adhere to the drill margin and impart damage to the CFRP wall of the hole. For a number of holes less than 50, water-mist-cooling reduces tool abrasion. However, the abrasion increases suddenly for hole numbers greater than 50. Accordingly, for the number of holes drilled well over 50, tool life is longer in dry processing than in water-mist-cooling.
T. Tashiro et al., "Drilling of CFRP/Ti-6Al-4V Stacks", Advanced Materials Research, Vol. 325, pp. 369-374, 2011