Oozing characteristics in screw extrusion additive manufacturing

Résumé fourni par la source

Abstract Additive Manufacturing (AM) is a non-conventional manufacturing process that enables the physical realization of components through layer-by-layer material deposition. Among the different AM techniques, Screw Extrusion Additive Manufacturing (SEAM) uses an extruder screw system that allows continuous extrusion and selective deposition of material during the printing process. However, similar to other material extrusion methods, SEAM also suffers from the issue of oozing, which is a form of over-extrusion where excess material builds up around the nozzle or over the deposited surface. This unwanted material flow often causes poor surface finish, dimensional inaccuracies, and degradation in the overall print quality. Therefore, it is important to predict and understand this behavior through mechanistic modelling. In this research, a novel mathematical model is proposed for estimating the amount of oozed-out material during the SEAM process of thermoplastic ABS ( Acrylonitrile Butadiene Styrene ). The phenomenon of oozing is assumed to occur due to screw twisting caused by viscous drag and pressure build-up inside the screw barrel system during extrusion. The developed model is experimentally verified using an indigenously fabricated screw extruder setup under different combinations of screw speed and barrel temperature conditions. The results indicate that the oozing mass increases with screw speed, while a stronger negative dependence is observed with increasing barrel temperature. A high level of correlation greater than 90% is obtained between the predicted and experimental values, which validates the effectiveness and reliability of the proposed mathematical model.

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