Research on the prediction of material removal and over-grinding optimization for abrasive flow machining of 3D printed right-angle bends

Abstract Addressing the issue of over-grinding on the outer side of right-angle bends in abrasive flow machining due to the gradient change of abrasive inertia force, a model for predicting material removal and an optimized structure for right-angle bends, both based on abrasive flow machining, are proposed. In this paper, the 3D-printed aluminium alloy right-angle bends are used as experimental objects, and the Carreau-Yasuda equations are fitted for simulation and analysis after rheological testing of the medium used in the test. A predictive model for material removal was developed by integrating simulated channel pressure with machining cycles, and its effectiveness was validated through experiments. Using this predictive model for structural optimization of bends, an unevenly thickened optimized right-angle bend was designed. The machining tests verified the accuracy of the simulation analysis, and the over-grinding region of the right-angle bend appeared at the maximum of the pressure region in the numerical simulation. At a processing pressure of 10 MPa and cycles of 20, 60, and 100, the prediction model resulted in material removal errors of 6.94%, 8.93%, and 13.31% respectively for the outer side of the bend, indicating a good fit of the prediction model. The optimized bend designed according to the predictive model exhibited an 80.37% reduction in overall deviation at the elbow compared to conventional right-angle bends, and a 67.31% reduction in contour deviation at the area most affected by inertia forces, effectively mitigating the issue of over-grinding at the elbow. This research facilitates quantitative control of material removal in abrasive flow machining of right-angle bends and provides theoretical support for non-uniform thickness design in bends.