A 3D Printed Morphing Nozzle to Control Fiber Orientation during Composite Additive Manufacturing

Abstract

Fiber‐filled composite materials offer a unique pathway to enable new functionalities for systems built via extrusion‐based additive manufacturing (or “3D printing”); however, challenges remain in controlling the fiber orientations that govern ultimate performance. In this work, a multi‐material, shape‐changing nozzle—constructed by means of PolyJet 3D printing—is presented that allows for the spatial distribution of short fibers embedded in polymer matrices to be modulated on demand throughout extrusion‐based deposition processes. Specifically, the nozzle comprises flexible bladders that can be inflated pneumatically to alter the geometry of the material extrusion channel from a straight to a converging–diverging configuration, and in turn, the directional orientation of fibers within printed filaments. Experimental results for printing carbon microfiber‐hydrogel composites reveal that increasing the nozzle actuation pressure from 0 to 100 kPa reduced the proportion of aligned fibers, and notably, prompted a transition from anisotropic to isotropic water‐induced swelling properties (i.e., the ratio of transverse to longitudinal swelling strain decreased from 1.73 ± 0.37 to 0.93 ± 0.39, respectively). In addition, dynamically varying the nozzle geometry during the extrusion of continuous composite filaments effects distinct swelling behaviors in adjacent regions, suggesting potential utility of the presented approach for emerging “4D printing” applications.

3D‐Printed Anisotropic Polymer Materials for Functional Applications

“…Reproduced with permission. [ 78 ] Copyright 2021, WILEY‐VCH Verlag GmbH. d) Schematic illustration of cellulose fibril alignment (top left), images of stained fibrils in different processes (bottom left), and biomimetic 4D printing of the samples composed of different printing paths (right).…”

Fully 3D-printed soft robots with integrated fluidic circuitry

“…The designs and protocols for additively manufacturing all of the components and systems in this work were based on the use of an Objet500 Connex3 PolyJet 3D printer (Stratasys, Eden Prairie, MN) and are similar to those reported in our previous work (57). Initially, all of the fluidic circuit elements, soft actuators, ports, and integrated soft robotic systems were modeled using the CAD software SolidWorks (Dassault Systèmes SE, France).…”

“…Theoretical simulations of the fluidic transistors were performed using the commercial FEA software COMSOL Multiphysics v.5.3a (COMSOL Inc., Sweden) via methods similar to those reported in our previous work (57). Initially, the complete 3D CAD model (i.e., including both materials fully assembled) corresponding to each fluidic transistor was imported into the FEA software, and then the distinct material properties were set for the compliant and rigid components.…”

Effect of Extrusion Parameters on Short Fiber Alignment in Fused Filament Fabrication

“…The influence of different angles of the internal geometry of the nozzle in the convergent section before the orifice on the pressure necessary for extrusion has also been investigate in terms of fiber shortening [ 49 ]. In direct write AM a nozzle with changing orifice diameter has been reported that can influence the fiber orientation by changing from a convergent to a divergent flow [ 50 ].…”