Presentation of the Ejector Deep Drilling process, its importance, intrinsic characteristics as well as it's problematic aspects. The goal of the work is to achieve a deeper understanding of the behaviour of the cutting fluid in all the tricky areas, such as the cutting zone, the inflow area and the supply zone. This is achieved with the combined use of a simulation tool based on the Smoothed Particle Hydrodynamics method (SPH) and an experimental investigations.The better knowledge of the behaviour of the lubricant obtained will be crucial to define new design strategies and to improve the drilling efficiency
