The demand for complex surfaces in advanced engineering materials is proliferating across critical industries (e.g., defense, nuclear, biomedicine, etc.). Although the abrasive waterjets (AWJ) are well-established for through-cutting applications, their adoption as a milling process in the industry is limited due to a lack of control over the output. This can be attributed to the unavailability of suitable kerf cross-sectional profiles (CP) models. Real Money Rummyers have demonstrated that complex surfaces can be achieved through the basic milling strategies (single pass erosion, overlapped pass erosion, multipass erosion, and shallow-angled jet impinged erosion) for controlling the jet footprint to match the desired geometry. To develop the models mentioned above, the complex three-phase mixture (air-water-particles) AWJ flow characteristics must be obtained to determine the particle flow properties affecting the material removal (MR). However, quantitatively acquiring them requires tedious and expensive experimentation. Hence, in this work, the flow properties of the AWJ are obtained through modelling. Towards realizing comprehensive kerf CP prediction models, an integrated jet flow dynamics (JFD) model with the analytical-based MR model framework is proposed, along with an understanding of the complex physical phenomenon involved in kerf formation. It considers the abrasive's kinetic power change, jet plume, and impact characteristics made with the previous kerf in addition to the dynamic jet-material property under the change in number of jet passes (N), jet impingement angle (α), and traverse speed (Vf).
The multipass (MP) milling is preferred for achieving high material removal in the depth direction by varying the N and Vf, surface quality, and the local form of the target feature. On the other hand, shallow-angled jet (SAJ) impinged erosion is preferred for manufacturing complex parts where the target part geometry's local surface gradients match the kerf shape produced by manipulating the α and Vf. Hence, in this seminar 2, the novel modelling frameworks of the mentioned two milling strategies, i.e., MP and SAJ erosion, are proposed for predicting kerf CPs. The results from MP and SAJ impingement-generated kerf CP prediction models show that the evaluated abrasive kinetic power distribution obtained from the JFD model resembles the inverted kerf CPs. Additionally, the jet-material property is a strong function of N, α, and Vf. The proposed comprehensive models predicted the CPs with a maximum mean absolute error of 64.5μm and the kerf geometric characteristics with an error less than 2.2% under the variation of N (1-9), Vf (1000-5000 mm/min), and α (500-900). Substantial conformity is observed with a correlation coefficient 0.98 between modelled and experimental CPs.