As aircraft programs currently ramp up, productivity of assembly processes needs to be improved while keeping quality, reliability and manufacturing cost requirements. Efficiency of the drilling process still remains an issue particularly in the case of CFRP/metal stacks: hot and long metallic chips are difficult to remove and often damage the surface of CFRP holes.
Low frequency axial vibration drilling has been proposed to solve this issue. This innovative drilling process allows breaking up the metallic chips in such a way that jamming is avoided.
This paper presents a case of CFRP/Ti6Al4V drilling on a CNC machine where productivity must be increased. A comparison is made between the current regular process and the MITIS drilling process. First the analysis and comparison method is presented. The current process is analyzed and its limits are highlighted. Then the vibration process is implemented and its performances are studied. Both processes are compared according to the following criteria: chip morphology, thrust force, power consumption, tool life, cycle time, holes quality and manufacturing costs.
Results show that the vibration drilling process is more productive and reliable, while maintaining the quality as well as reducing manufacturing costs. The paper also shows that the vibration drilling allows simplifying cutting tool design and reducing lubrication.
