The technology behind metal additive manufacturing (AM) has advanced rapidly over the last ten years, demonstrating a significant potential to reduce the cost and improve the efficiency of aerospace components. With improvements to design freedom and light-weighting via topology optimisation as well as improved buy-to-fly ratios and reduced tooling costs, there has been a positive impact on the carbon footprint and waste from manufacture. H2020-EU “PASSPORT” project led by TWI conducted a detailed characterisation of AlSi10Mg components made by laser powder-bed-fusion (L-PBF), also known as selective laser melting (SLM). An important aspect of the project is to apply optimised process parameters in multiple vendors’ SLM machines. This is a challenging task by itself as different SLM machines using specific laser characteristics (i.e. laser focus diameter, continuous or pulsed energy deposition mode) use process parameters that cannot be directly transferred into other machines featuring laser systems with different characteristics. Limitations of typical SLM design parameters could not satisfy PASSPORT demands in terms of a universal process optimisation methodology independent of SLM machine used. The need of a more holistic approach using novel design parameters was identified.
Characterisation of AlSi10Mg components made by Selective Laser Melting
This case study presents a novel design approach developed at TWI to implement the PASSPORT solution in different vendors’ SLM machines. This approach consisted in using the power factor and specific point energy to characterise the SLM process. PASSPORT leveraged TWI unique numerical modelling and process monitoring for developing a more holistic process optimisation solution. TWI has been investigating geometry-specific process parameters to enable a near-uniform thermal history based in the process specific point energy.
To develop state-of-the-art, optimised process parameters that vary with local part topology and geometry characteristics to ensure high quality AlSi10Mg components.
The PASSPORT project seeks to achieve this through the development of state-of-the-art, ambitious, analytical software in order to remove the barriers associated with transferring process parameters between different SLM systems.
In order to reach the stated objective, the PASSPORT project used a unique laboratory set-up to undertake a detailed characterisation of AlSi10Mg selective laser melted (SLM) parts.
With the use of advanced simulations, the project sought to understand and quantify the relationship between scan strategies and part attributes. These optimised process parameters could then vary according to local part topology and geometry characteristics to ensure quality through homogeneous mechanical properties, high density and a smooth build surface.
This required the production of a bespoke stand-alone process parameter selection software solution for AlSi10Mg SLM parts, which could communicate with different SLM machines using optimal processing windows with holistic energy maps.
The desired outcome of this work was to improve the time-to-market for SLM parts by removing cost and time-intensive optimisation processes for SLM builds.
Regional Team Manager – Numerical Modelling and Optimisation
Tyler joined the Numerical Modelling and Optimisation section of TWI in 2011 after obtaining an MSc in Mathematical Modelling & Scientific Computing from the University of Oxford. He specialises in engineering analysis: applying mathematical modelling and finite element analysis to support research, product development and failure investigations related to structural integrity and materials performance. Tyler is a Chartered Engineer, Chartered Mathematician, Chartered Scientist and a NAFEMS-certified, advanced-level Professional Simulation Engineer. He has published over 20 peer-reviewed publications and conference papers, and actively participates in many national and international codes and standards committees including BS 7910 residual stress, R6 weld modelling guidelines, and the EN 13094 FEA sub-group.