Direct Ink Writing of Recycled Composites with Complex Shapes: Process Parameters and Ink Optimization

Abstract

Within the complex framework of additive manufacturing, direct ink writing (DIW) processes significantly contribute to extending the range of 3D‐printable materials (i.e., thermosetting resins, ceramics, hydrogels). Thanks to this technology, viscous inks are easily extruded for the creation of 3D structures. Nevertheless, the quick recovery of the solid‐like behavior after extrusion remains one of the most crucial open issues for 3D‐printable inks. The main goal herein is to improve the printability of a UV‐curable thermosetting composite ink reinforced with mechanically recycled glass fiber composites by modifying its rheological behavior. The overall process is optimized, leading to the definition of the optimal extrusion parameters for these types of materials. Furthermore, the retraction mode is successfully developed for the DIW of recycled composites. Additional features are achieved, thanks to the aforementioned improvements, such as 3D complex shapes, assembled pieces, and/or moving built‐in mechanisms, increasing the number of new potential applications of recycled glass fiber‐reinforced polymers.

Hangprinter for large scale additive manufacturing using fused particle fabrication with recycled plastic and continuous feeding

“…The sample was sliced with a layer height of 1 mm, one perimeter, no bottom/top layers, and 0 % infill. The samples were then visually inspected and measured to compare the actual weight, time, average line width, and overall dimensions with the nominal ones [84] , [85] , [28] . The expected weight was calculated by inserting the density value from the NatureWorks technical datasheet in PrusaSlicer (Prusa Research, Prague, Czech Republic).…”

Soft self-healing resistive-based sensors inspired by sensory transduction in biological systems

“…The most common AM method for hydrogels is the direct ink writing or robocasting process [135]. Both fabrication processes belong to the material extrusion AM method, where a paste-like material is extruded through a nozzle on a printing bed platform to form a 3D object with layer-by-layer deposition [136,137]. For the extrusion process the materials must exhibit shear-thinning and thixotropic response.…”

Metallization of Recycled Glass Fiber-Reinforced Polymers Processed by UV-Assisted 3D Printing

“…Similarly, using PVD sputtering processes for polymer-based composites may generate potential benefits, especially for recycled substrates. Focusing on the case study of this paper, high-performance applications could be exploited by using coated recycled GFRPs, such as technical parts, outdoor furniture, or customized scenery elements [17,48]. In detail, these kinds of recycled GFRPs exhibit interesting mechanical properties for similar applications, showing good values of elastic modulus (~5.5-6 GPa) and toughness (~200 J/mm 3 ), which can be comparable to virgin GFRPs [17].…”