Browsing by Subject "viscosity control"

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Viscosity Control of Pseudoplastic Polymer Mixtures for Applications in Additive-Manufacturing
(University of Texas at Austin, 2018) Vaish, Apoorv; Yang Lee, Shien; Valdivia Alvarado, Pablo
Various additive manufacturing (AM) processes exploit the rheological properties of non-Newtonian (e.g. pseudoplastic) polymers for stability and feature realization. For embedded 3D-printing (e3DP) and direct ink writing (DIW), features are deposited on top or within a layer of matrix/base material and the rheological properties of the matrix are crucial for satisfactory prints. Due to their high apparent viscosities under static conditions, these base polymers do not flow easily when poured in bulk into the fabrication space. Traditionally, manual methods were employed to spread them into an even layer. In this study, an alternative approach to spread and level pseudoplastic polymers using oscillatory shear stresses generated by a vibrating actuator is presented. The proposed approach lowers the viscosity of the polymers, thereby facilitating gravity-driven flow to generate a flat polymer-air interface. A fluid rheology model detailing the parameters influencing the process is presented and experiments are performed using these parameters.