Optimisation of process parameters for lattice structures

Abstract

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 -Selective laser melting (SLM) is a commonly known and established additive manufacturing technique and is a key technology in generating intricately shaped lattice structures. However, standard process parameters used in this technology have building time and accuracy disadvantages for structures with a low area-to-perimeter ratio, such as thin struts. Within this study, a set of process parameters tailored for lattice structures is developed and tested against standard process parameters. Design/methodology/approach -In this research work, body-centred cubic (BCC) structure specimens are manufactured using adapted process parameters. Central to the adapted process parameters is the positioning of the laser beam, the scan strategy, and the linear energy density. The specimens are analysed with X-ray micro-computed tomography (micro-CT) for dimensional accuracy. The final assessment is a comparison between specimens manufactured using adapted process parameters and those using standard process parameters. Findings -Standard parameters for lattice structures lead to a significant shift from the nominal geometry. An extensive manufacturing and computation time due to several exposure patterns (e.g. pre-contours, post-contours) was observed. The tailored process parameters developed had good dimensional accuracy, reproducible results, as well as improved manufacturing performance.Research limitations/implications -The results are based on a distinctive geometry of the lattice structure and a specific material. Future research should be extended to other geometries and materials. Practical implications -Optimisation of process parameters for the part geometry is a critical factor in improving dimensional accuracy and performance of SLM processes. Originality/value -This study demonstrates how application-tailored process parameters can lead to superior performance and improved dimensional accuracy. The results can be transferred to other lattice structure designs and materials.

Numerical prediction of the printable density range of lattice structures for additive manufacturing

“…Abele et al [48] claimed that building orientation has not any meaningful effect on the printability of scaffolds in SLM processes. They also claimed that powder adhesions have not any meaningful effect.…”

Selective laser melting of novel titanium-tantalum alloy as orthopaedic biomaterial

“…This implies that horizontal struts should be avoided unless they can be supported with other struts. The results coincide with findings by Abele et al [131].…”

“…Yan et al also attributed powder adhesion due to balling phenomenon which give rise to beads being formed mainly on laser melted surfaces perpendicular to the building direction [34]. However, Abele et al concluded that building orientation has no significant effect on the manufacturability of lattice structures by SLM [131], which implies that these powder adhesions have no significant effect on the short term mechanical properties. However, the powder adhesion can act as stress concentrators which facilitate fatigue crack initiations, affecting fatigue strength of the porous structures [132,133].…”

Selective Laser Melting Strategy for Fabrication of Thin Struts Usable in Lattice Structures

“…The dependence of the main process parameters on the strut porosity was evaluated, but only for one LP and LS level. Abele et al [ 16 ] dealt with dimensional accuracy of the strut structure. The authors tested a laser strategy for lattice structure production focused on high dimensional accuracy of very thin struts (d = 0.2 mm).…”