Optimisation of process parameters for lattice structures

This paper aims to develop a set of process parameters tailored for lattice structures and test them against standard process (SP) parameters. 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, SP parameters used in this technology have building time and accuracy disadvantages for structures with a low area-to-perimeter ratio, such as thin struts.

In this research work, body-centred cubic 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 for dimensional accuracy. The final assessment is a comparison between specimens manufactured using adapted process parameters and those using SP parameters.

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 and improved manufacturing performance.

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.

Optimisation of process parameters for the part geometry is a critical factor in improving dimensional accuracy and performance of SLM processes.

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.