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3D printing has been recognized as the future manufacturing technique by different industries. The properties of products manufactured using this technique depend upon large number of factors, with print orientation being one among the most important factors. Currently, there is no standard for the build orientation of the printed component. To date, the analysis of material properties is conducted by testing specimens printed in different orientations. The present work explores the effect of layer orientations on the different mechanical properties of an SLA manufactured polymer material. Five different orientations, i.e. 0°, 22.5°, 45°, 67.5° and 90° were used to print the specimens for the analysis of mechanical properties of the material. Tensile, compression, flexural, impact, fatigue and vibration analysis are the different mechanical tests that were conducted as per their respective standards. It was found that the print orientation plays a significant role in the behaviour of the respective mechanical property. The maximum tensile and compressive load are being taken by the specimens printed at an angle of 22.5° and 67.5°, respectively. The specimen printed at 67.5° orientation again have highest flexural strength, whereas the specimen printed at 0° have higher impact and fatigue strength.

Advancements in 3D print technology now allow the printing of structured acoustic absorbent materials at the appropriate microscopic scale and sample sizes. The repeatability of the fundamental cell unit of these metamaterials provides a pathway for the development of viable macro models to simulate built-up structures based on detailed models of the individual cell units; however, verification of such models on actual manufactured structures presents a challenge. In this paper, a design concept for an acoustic benchmark metamaterial consisting of an interlinked network of resonant chambers is considered. The form chosen is periodic with cubes incorporating spherical internal cavities connected through cylindrical openings on each face of the cube. This design is amenable to both numerical modelling and manufacture through additive techniques whilst yielding interesting acoustic behaviour. The paper reports on the design, manufacture, modelling, and experimental validation of these benchmark structures. The behaviour of the acoustic metamaterial manufactured through three different polymer-based printing technologies is investigated with reference to the numerical models and a metal powder-based print technology. At the scale of this microstructure, it can be seen that deviations in surface roughness and dimensional fidelity have a comparable impact on the experimentally measured values of the absorption coefficient.

Advancements in 3D print technology now allow the printing of structured acoustic absorptive materials at appropriate microscopic scales and sample sizes. Optimisation of parameter sets associated with a Kelvin Cell structure have the potential to develop various metabehaviours in the associated acoustic responses. The repeatability of the fundamental cell unit also provide a route for the development of viable macro models to simulate built up structures based on detailed models of the individual cell units. This paper describes a process to model, print and test such a sample. Manufacturing restraints will initially guide the optimised design and introduce response uncertainties associated with surface finishes and critical geometric dimensions. A "micro to macro" model is developed using a full visco thermal acoustic model of a single cell to develop a frequency dependent cell transfer matrix. The transfer matrices for the repeated cells may then be combined until sufficient material depth is achieved and efficiently generate an absorptivity for the material layer. Two prints using different processes (digital light processing (DLP) and selective laser melting (SLM)) of nominally the same kelvin cell structure. For the metal print the model predicts the absorptivity well once an allowance is made for the surface roughness. The DLP has a smoother finish with a lower geometric fidelity however the DLP sample is still well modelled by the process.

Stimuli‐responsive hydrogels have attracted much attention owing to the versatility of their programmed response in offering intelligent solutions for biomimicry applications, such as soft robotics, tissue engineering, and drug delivery. To achieve the complexity of biomimetic structures, two photon polymerization (2PP) has provided a means of fabricating intricate 3D structures from stimuli‐responsive hydrogels. Rapid swelling hydrogel microstructures are advantageous for osmotically driven stimuli‐response, where actuation speed, that is reliant on the diffusion of analytes or bioanalytes, can be optimized. Herein, the flexibility of 2PP is exploited to showcase a novel sugar‐responsive, phenylboronic acid‐based photoresist. This offers a remarkable solution for achieving fast response hydrogel systems that have been often hindered by the volume‐dependent diffusion times of analytes to receptor sites. A phenylboronic acid‐based photoresist compatible with 2PP is presented to fabricate stimuli‐responsive microstructures with accelerated response times. Moreover, microstructures with programmable actuation (i.e., bending and opening) are fabricated using the same photoresist within a one‐step fabrication process. By combining the flexibility of 2PP with an easily adaptable photoresist, an accessible fabrication method is showcased for sophisticated and chemo‐responsive 3D hydrogel actuators.

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