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Over the last few years, many aircraft production lines have seen their production rate increase. In some cases, to avoid bottlenecks in the assembly lines, the productivity of processes needs to be improved while keeping existing machine-tools. In this context, the case of drilling machine-tools tends to require particular attention, especially when multi-material parts are drilled. In such instances, the Vibration Assisted Drilling (VAD) process can be a way to improve productivity and reliability while keeping quality standards. This article presents a case of a drilling/countersinking process for stainless steel and titanium stack parts. Firstly, the article assesses the feasibility and benefits of using Vibration Assisted Drilling and Countersinking with the current cutting-tools. Secondly, it studies the consequences of introducing a new tool holder in the process, which combines the V.A.D. function, a new declutching function and the ability to control countersink depth.

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.