Orthopaedic regenerative medicine requires the design of scaffolds and implants that replicate the biomechanical properties of bones. Porous implants, designed with bespoke mechanical performance using state-of-the-art of topology optimization and produced by additive manufacturing, are suitable candidates for repairing or replacing damaged bones.
In Electron-beams systems, the back-scatter of electrons at the layer surface produces local electrical charge build-up and electrostatic ejection of particles from the powder bed: ’smoking’.
Although the exploitation of AM technologies continues to accelerate, a key barrier to adoption of AM is the need for in-process monitoring and process control [1, 2].
Equivalence-based and model-based certifications require reliable data set to validate complex multi-physics models. To move towards the certify-as-you-build scheme, industries call for sound in-situ process monitoring and quality control.
A few months ago, we were wondering about process control in powder bed fusion of reactive powders. What are the impacts of particles’ surface contamination on the fabrication of metal components? And what are the best ways to minimise it during the complete manufacturing cycle?
Then, very few studies were trying to assess the impact of powder particles surface chemistry on the process (powder spreading, melt wettability, pores formation, etc…) and on the final product characteristics (relative density, etc).
As more data get publicly available, we can present the results of a detailed investigation aiming to 1) understand the effects of powder surface chemistry, 2) minimise particles surface contamination on the finished products and 3) improve SLM process control.
Various strategic efforts have been conducted to develop AM [1,2] and define qualification and certification needs [3,4]
Yet, a current lack of standardised measurements science and protocols impedes the wider acceptance of industrial AM. Few companies can afford to develop their own internal foundations for qualification of materials, processes, and parts built with AM .
Researchers at the University of Sheffield, UK, are developing a new additive manufacturing technique that aims to minimise the presence of residual stresses in components. The project, funded by EPSRC UK, aims to develop a novel, low cost metallic Additive Manufacturing process that induces low thermal stress during manufacturing: Layered Extrusion of Metal Alloys (LEMA).
What happens when you combine in a single setup the benefits of WAAM with in-process grain refinement, online monitoring and final machining? You could end up with an attractive commercial opportunity to make large aerospace components at reasonable price. In the first article of this two-part series, we present a ‘ready to use’ additive manufacturing technology. The second part will address typical costs and applications.