A generic model for prediction of kerf cross-sectional profile in multipass abrasive waterjet milling at macroscopic scale by considering the jet flow dynamics

Multipass abrasive waterjet (AWJ) milling is preferred for achieving high material removal, surface quality, and the local form of the target feature. However, the lack of generic models for the kerf generated in multipass erosion for realizing complex features limits AWJ’s penetration into the industry. The kerf formed in multipass erosion involves a complex physical phenomenon, which is influenced by the jet characteristics and the way of material removal (MR). This work proposes a generic kerf cross-section profile (CP) prediction model in multipass milling on Ti-6Al-4 V alloy. The proposed approach integrates the jet flow dynamics (JFD) model with the analytical-based MR model, along with understanding the complex physical phenomenon involved in kerf formation towards realizing a comprehensive model. It considers the abrasive's kinetic power change with effective jet divergence, effective standoff distance, local particle impact angles made with the previous kerf, and the dynamic jet-material property, under varying jet traverse rate (Vf) and the number of passes (N). The proposed model was assessed for its generalization capability by comparing the predicted CPs against experimental ones under varying Vf and N. The results show that the evaluated abrasive kinetic power distribution obtained from the JFD model resembles the inverted kerf CPs. The comprehensive model predicted the CPs with a maximum mean absolute error of 64.5 μm and the centreline depth with a maximum error of 2.2% under the variation of Vf (1000–5000 mm/min) and N (1–9). The modelled kerf CPs conformed with the experimental ones with a 0.97 correlation coefficient.