Shallow-angled jet impingement generated channel geometry prediction in milling Ti-6Al-4V alloy

Abstract

To manufacture complex parts using abrasive waterjets (AWJs) in milling mode, one should ensure that the local features of the target part geometry match with the channel shape produced by manipulating the operating parameters, such as jet impingement angle (α) and traverse speed (V_f). Hence, generating surfaces with tight tolerances demands control over the channel cross-section profile (CP) and its characteristics (maximum erosion depth, top width, cross-section area, and trailing edge angle). Despite AWJ technology's existence for decades, there have been limited attempts to obtain control over channel geometries. Since AWJ is a complex three-phase mixture (air-water-particles), determining the particle flow properties in AWJ for material removal is of utmost importance. These circumstances seek to establish a modelling approach for predicting the channel geometry under the change in α and V_f. This paper proposes an innovative model for predicting CPs obtained at shallow-angle jet (SAJ) impinged erosion trials, incorporating the insights gained on channel formation mathematically. The Ti-6Al-4V alloy is highly challenging to mill by conventional methods used for experiments. The modelling results demonstrate that by considering the mathematical relationship between the specific cutting energy associated with α and V_f and corresponding jet flow properties in the model, the prediction capability improved by 98 %. Overall, within the range of α (50⁰–90⁰) and V_f (3000–5000 mm/min), the model's prediction error of channel characteristics is <10 %, and the mean absolute error in channel shape is 22.74 μm. Strong conformity is observed with a correlation coefficient of 0.98 between modelled and experimental profiles.