Additive Manufacturing
3D printing of large scale metallic components *
Additive manufacturing is a game changing technology with enormous potential impact; enabling new component capabilities that cannot be realised with any other technology, facilitating onsite/remote fabrication and reducing lead-times, storage and transportation costs.
Ideally, industry should have access to knowledge and techniques to design components with properties tailored to any required application. Design capabilities should include monolithic components with different property requirements at different locations. The first steps toward this material-centric based design approach are currently being taken in the joint industry NWO supported AiM2XL programme initiated by myself. Component design requires knowledge and control over metallurgical structures and resultant properties as well as residual stress states and component distortion. With sufficient modelling understanding of the influence of processing conditions on the material, it should be possible to design and build components with properties-on-demand at any desired location. Details of this programme can be found by following the links provided.
Manipulation of the local deposition conditions, including temperature and mechanical loading, provides a considerable level of control over the structure and properties of the deposit. One example of such control has been demonstrated during the production of a Bronze ships propeller, produced by RAMLAB in Rotterdam. Traditionally, such a propeller would be cast. Due to the relatively slow cooling involved, a cast nickel aluminium bronze will contain a number of large and undesirable precipitates. In contrast the cooling rates of a 3D printed component can be controlled to avoid undesirable precipitate formation, leading to a material with superior mechanical and corrosion resistant properties.
Above: a schematic representation of the precipitate and phase structure of a CuAl8Ni6 alloy.
Below: a comparison of the structure of the alloy after casting (left) and after wire arc additive manufacturing (WAAM) (right).
* Ya, W.; Goulas, C.; Hamilton, K.; Hermans, M.C.M.; Romer, G.R.B.E. and Richardson, I.M. “Microstructure and mechanical properties of CuAl8Ni6 produced by Wire Arc Additive Manufacturing for marine applications”. EUROMAT congress, 17-22 September Thessaloniki, Greece, 2017.
AiM2XL programme aims and research lines.
Wire Arc Additive Manufacturing (WAAM) of a ships propeller (above) and temperature distribution during production (below).
