Strategies in 3 and 5-axis abrasive water jet machining of titanium alloys

Titanium alloy is generally used for aeronautical structural parts having a large size and as thin walls while having to withstand considerable effort. Machining these parts is difficult with conventional methods such as milling, because the high cutting forces can easily deform the part. Machining of titanium alloy (Ti6Al4V) by an abrasive water jet (AWJ) process can potentially be used to replace conventional machining methods. However, the understanding of the different aspects of this process is insufficient to allow its industrialization. This thesis presents a model of prediction of the machined depth in two cases of direction of the jet: a jet perpendicular to the surface of the part and an inclined jet. At first, the understanding of the removal material process and the obtained surface quality is studied through the observation of the influence of the process parameters. In a second step, a model based on the Gaussian distribution of abrasive particles in the water jet is proposed to characterize an elementary pass and to predict the pocket bottom profile obtained by a succession of elementary passes. Then, a method to machine pocket corners using an adaptive control of the feed rate is presented. Finally, a new model of the pocket bottom profile taking into account the angle of inclination of the jet is presented. Throughout this thesis work, the experimental validation showed a good agreement between the measured and modeled values and thus demonstrated the ability of the abrasive water jet milling to machine to a controlled depth.