​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).

The LEMA process is a new innovate Additive Manufacturing method for directly forming metal structures. Loosely inspired from the Fused Deposition Modelling (FDM) process used with polymers, the main benefits planned may include

• a reduction in thermal stresses within formed components;
• lower system cost;
• and higher energy efficiency.

Other benefits potentially include a reduced shrinkage during solidification of parts, broader use of material feedstock with variable morphologies and further geometric freedom with creation of unsupported overhanging features.

A combination of unique feedstock chemistry and careful process control will allow efficient extrusion of materials with a reduction in thermal gradients compared to powder bed fusion systems.

It is anticipated that lower thermal gradients generated during extrusion will allow parts to be created with minimum distortion and potentially reduce the number of supporting features normally required with powder bed fusion systems. Unsupported geometries may even be created and enhance design freedom.

The initial hardware investments are likely to be considerably lower compared to laser or electron beam based systems and promote easy access to this technology.

Operating at lower operating temperatures is also anticipated to reduce manufacturing costs.