Additive manufacturing has been the driving force behind the growth of metamaterials as a field. Commonly taking the form of lattices, these structures can achieve a range of novel macroscale properties that stem from the cumulative effects of locally designed mechanisms. A wide array of mechanical metamaterials have already been designed using computational methods, but these rarely undergo physical testing, often as a result of manufacturing difficulties. This work approaches the problem of manufacturing complex metamaterial test samples though a case study of 3D petal-based auxetic star lattices. These lattice structures have linkage structures with overhanging elements, which is a common feature in metamaterial concepts but challenging to print. Trials of the test samples were manufactured using a thermoplastic polyurethane filament combined with polyvinyl acetate support at 20, 30 and 40 mm unit cell sizes. It was found that the main geometric challenges for successful printing were the link thickness and the reliability of the prints. To address unreliability, the geometry was cut into layers of cells with adhesive-connected feet and printed in parts for post-process assembly. The layered approach was tested successfully and was estimated to reduce the number of cells needed to be attempted to print the full lattice by over 80%. The use of dissolvable support material proved viable for printing overhanging links, but requires use of fused deposition modelling so a relatively low part resolution. The trial led to a five point design guide methodology for metamaterial test samples. Combined with cell mathematical definitions that strictly bound link thickness to take minimum print resolution into account, this methodology can be applied to other metamaterials and help bridge the gap between theoretical lattices and physical testing.
This research presents a novel framework for the design of additively manufactured (AM) composite tooling for the manufacture of carbon fibre-reinforced plastic composites. Through the rigorous design and manufacture of 30 unique AM tools, the viability of a design for AM framework was evaluated through measuring the performance with respect to geometrical accuracy and thermal responsiveness, and simulating the tool specific stiffness. The AM components consisted of a thin layup facesheet, stiffened by a low density lattice geometry. These tools were successfully used to layup and cure small composite components. The tooling was highly thermally responsive, reaching above 93% of the applied oven heating rate and up to 17% faster heating rates compared to similar mass monolithic tools. The results indicate that thermal overshoot has a greater dependence on the lattice density while the heating rate was more sensitive to the facesheet thickness. Lattice densities of as little as 5% were manufactured and the best overall geometry was a graded gyroid lattice with thicker walls near the surface and thinner walls at the base, attached to a 0.7 mm thick facesheet. The outputs from this research can provide a new route to the design and manufacture of mould tools, which could have significant impacts in the composites sector with new, lighter, more energy efficient tooling.
As the flexibility and reliability of additive manufacturing (AM) and its corresponding design tools increases, it is becoming a viable option for more industries. One application area that could benefit from AM is composite component manufacture. The layup and molding of composite materials face significant challenges presented by tight design timescales, growing demand for productivity, and the complexity of components and end products. Therefore, there is an immediate potential to save energy by reducing the mass of the curing equipment and tooling to enhance process heat transmission. The goal of this paper is to demonstrate the reduction of embodied energy within mold tools that are printed using an AM process. Using an AM approach, it is possible to design lightweight curing tools to increase the curing rate and quality of heat distribution in the mold. The viability of additively producing these cure tools was assessed by analyzing the geometrical precision of the composite mold outputs, material utilization, and heat transmission qualities of each sample. In this study, 14 cure tools were designed and manufactured with a 100 mm2 curing surface area, top plate thickness of 1–2 mm, and stiffening lattices behind the curing surface with a depth of 10 mm. Four lattice geometries, gyroid, dual-wall gyroid, planar diamond, and stochastic, were tested based on their overall geometrical accuracy and thermal responsiveness. While the stochastic lattice had the best single tool properties, the planar diamond and gyroid lattice tools had better potential for future use in the design of additively manufactured composite tooling.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.