Abrasive flow finishing of 3D-Printed Aerofoils: Design, numerical Simulation, and experimental analysis

This study investigates the application of abrasive flow machining (AFM) to enhance the surface quality of 3Dprinted polylactic acid (PLA) parts, addressing the common issue of "stair casing" associated with layer manufacturing. Utilizing an FDM-printed 'aerofoil' as a representative workpiece, the eco-friendly Natural and Sustainable Abrasive Flow Media (NSAFM) is employed, consisting of Fuller's earth, silicon carbide particles, and groundnut oil. This media exhibits characteristics of low flow and non-adhesiveness post-contact. A mathematical model for material removal rate (MRR) is formulated, and simulations predict the movement of abrasive particles on the curved surface. This research also studies the ANN-MFO approach, where ANN has been used for modeling of input-output relations and parametric study, and Moth Flame Optimization (MFO) has been used to optimize the process. The experimental design, using Central Composite Design (CCD) with 20 runs, considers viscosity, layer thickness, and finishing time as process variables, with percent improvement in surface roughness (% Improvement Delta Ra) and MRR as response parameters. Furthermore, in the multi-objective optimization case with equal weights for both outputs (case 3), the maximum % Improvement Delta Ra (104.67) and MRR (2.980 mg) are achieved at a viscosity of 60 Pa-s, layer thickness of 0.3 mm, and a completion time of 83.23 min. Analyzing optical images of unfinished and finished aerofoil workpieces revealed that the stair-stepping phenomenon had been eliminated. Also, it clearly proves that the newly developed AFM media is ideal for finishing 3D printed components to eliminate the stair-stepping effect.