The rapid manufacturing process of selective laser melting has been used to produce a series of stainless steel 316L microlattice structures. Laser power and laser exposure time are the two processing parameters used for manufacturing the lattice structures and, therefore, control the quality and mechanical properties of microlattice parts. An evaluation of the lattice material was undertaken by manufacturing a range of struts, representative of the individual trusses of the microlattices, as well as, microlattice block structures. Low laser powers were shown to result in significantly lower strand strengths due to the presence of inclusions of unmelted powder in the strut cross-sections. Higher laser powers resulted in struts that were near to full density as the measured strengths were comparable to the bulk 316L values. Uniaxial compression tests on microlattice blocks highlighted the effect of manufacturing parameters on the mechanical properties of these structures and a linear relationship was found between the plateau stress and elastic modulus relative to the measured relative density.

This article presents a theoretical analysis for predicting the initial stiffness E*, and plastic collapse strength σ*pl of BCC micro-lattice blocks under compressive loading. This theoretical analysis is based on the observed deformation mechanisms, and can, in principle, be developed to predict the elastic properties of other micro-lattice structures. The analytical solutions are verified by comparing the predictions with FEM data using 1D beam and 3D solid elements and uniaxial compression tests on samples fabricated by selective laser melting. The FEM predictions using the 3D solid elements agree well with the experimental data for a wide range of strut aspect ratios, d/L. In addition, the range of applicability of the analytical model and the FEM predictions using beam elements are clarified.

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A range of metallic lattice structures were manufactured using the selective laser melting (SLM) rapid prototyping technique. The lattices were based assemblies of repeating unit-cells with their strands oriented at 0°, ±45°, and 90° to the vertical when viewed from the front. Mechanical tests on the strands and the lattice blocks showed that these systems exhibit a high level of reproducibility in terms of their basic mechanical properties. An examination of the compression failure mechanisms showed that the [±45°] and [±45°, 90°] lattices failed in bending and stretching modes of failure, whereas the [0°, ±45°] lattices failed as a result of buckling of the vertical pillars. Sandwich structures were manufactured by binding woven carbon-fiber reinforced plastic to the lattice structures. Subsequent three-point bend tests on these structures identified the principal failure mechanisms under flexural loading conditions. Here, cell crushing, hinge rotation, and gross plastic deformation in the strands were observed directly under the point of loading. Low-velocity impact tests were conducted on the sandwich beams and a simple energy-balance model was used to understand how energy is absorbed by the sandwich structures. The model suggests that the majority of the incident energy of the projectile was absorbed in indentation effects, predominantly in the core material, directly under the steel indenter.

If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -To fabricate and characterise novel heat sinks manufactured by selective laser melting (SLM). The investigation explores features of SLM produced heat sinks that may be exploited to improve their heat transfer capability. Design/methodology/approach -The study was conducted on heat sinks manufactured from 316L stainless steel and aluminium 6061. The heat transfer devices' thermal and pressure drop performances were determined by experimental test. Findings -The research demonstrates the performance enhancements that can be realised by using novel heat sink designs, fabricated by SLM, over conventional pin fin arrays. aluminium 6061 is used with the process to illustrate the improvement in heat transfer provided by higher conductivity feedstock materials. Research limitations/implications -Although the manufacturing technique is still in the development stage and the heat transfer devices that have so far been manufactured should not be considered optimal, the potential for creative new designs and applications is clear. This study highlights the need to develop the SLM process parameters to allow the repeatable production of heat transfer devices from higher conductivity metals with controllable surface finishes. Originality/value -This paper outlines the design issues and performance of novel heat transfer devices fabricated using SLM. A new material, aluminium 6061, is introduced to the family of materials that can be processed with SLM and example heat sinks are tested.