Layered Extrusion of Metal Alloys (LEMA)

Additive Manufacturing technologies are viewed as viable alternatives to conventional manufacturing processes, capable of creating geometrically efficient structures with low material waste. Commercial laser and electron beam metallic Additive Manufacturing systems are increasingly being used in high value aerospace and medical industries to directly manufacture metallic end-use parts. To manufacture components with full densities, these processes must completely melt the feedstock material, this subsequently generates large thermal stresses within formed components. Further to this, the hardware used within these high power laser/electron systems are inherently expensive and energy inefficient. This creates technical challenges and economic barriers that subsequently restrict new markets and industries from embracing this highly promising and disruptive manufacturing technology.

This proposal will develop a novel low thermal stress inducing, low cost metallic Additive Manufacturing process, Layered Extrusion of engineering Metal Alloys (LEMA). A specially created metallic feedstock will be extruded using a developed system designed to create layered 3D structures. A combination of unique feedstock chemistry and careful process control will allow efficient deposition of materials with a reduction in thermal gradients compared to conventional laser/electron based Additive Manufacturing systems.

The LEMA process is a new innovate Additive Manufacturing method for directly forming metal structures. Because there is no requirement for complete melting of a metallic feedstock within the LEMA process, it possesses a number of advantages over currently available commercial metal Additive Manufacturing processes. The main benefits 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. LEMA opens up a new exciting area in manufacturing science and process methodologies which will appeal to many disciplines generating further publications.

The UK manufacturing industry is most likely to directly benefit from outcomes of this research. As previously mentioned the lower thermal gradients generated within the process will allow parts to be created with minimum distortion and potentially a reduced number of anchors or supports normally required within conventional laser or electron beam based systems. Further to this it may be possible to create unsupported geometries, this would present a distinct capability advantage allowing more geometric freedom for the process. This research will communicate the capability advantages of low thermal stress manufacturing of components to current manufacturers of metallic Additive Manufacturing systems and end users.

Due to there being no requirement to fully melt feedstock, the LEMA process system hardware is likely to be considerably lower cost compared to conventional laser or electron beam based metallic systems. This will make the process cheaper allowing new markets to gain access to this technology and benefit from the opportunities that Additive Manufacturing presents (new products/industries, efficient manufacturing, job creation etc.). The low system cost will also allow the UK to be more competitive in response to global trends and market drivers.

With energy prices on the rise companies are seeking to maximise efficiency and reduce energy consumption. Convectional laser/electron based metallic Additive Manufacturing systems are largely energy inefficient, the LEMA process is likely to a have higher energy efficiency as a result of its lower operating temperatures. This will reduce costs for manufacturing and in the long term will benefit the environment because of lower overall energy demands.