The production of advanced high-tech components for aircraft and other aerospace applications is an expensive and time-intensive process involving design, prototyping and then machining of parts often using costly high strength-to-weight materials such as titanium. A new production approach developed under the European Union (EU) -funded RAPOLAC project (Rapid Production of Large Aerospace Components) can bypass the prototyping stage and build a new part in a fraction of the time with production costs reduced by as much as 40%.
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While the traditional machining approach cuts out metal from work pieces, the new Shaped Metal Deposition (SMD) process adds material layer by layer in a liquid metal deposition process. The end product requires minimal finishing, material waste is considerably reduced and the process has low to zero harmful emissions.
Large-scale aerospace parts can thus be built directly from the design model (CAD) with no need for a prototype stage and the 'parts' can be stored as programs and produced to order, thereby reducing inventory costs.
The SMD technology was initially developed by the aerospace manufacturer Rolls-Royce plc, but was not widely adopted for commercial produc-tion due to perceived technical limitations.
In 2005 the RAPOLAC project started with the aim to investigate and further refine the SMD process for use in the production of large compo-nents or for adding new metal features to existing parts.
The project was funded between 2007 and 2010 by the EU's 6th Framework Aeronautics and Space Programme and was coordinated by the Advanced Manufacturing Research Centre (AMRC) at the University of Sheffield in collaboration with partners in Belgium, Italy and Argentina who provided complementary expertise.
Under the RAPOLAC project, the consortium developed process models, documented material properties and carried out research on the automa-tion of the metal deposition process. The production parameters for different materials were established and the cost and environmental benefits were demonstrated.
The consortium's work showed that the SMD technology can potentially reduce the cost of manufacturing final products by 40%% through the reduction in raw material usage, energy costs and the elimination of specialist production tooling. The SMD approach can also help reduce the cost of inventory by 90% since the part designs are stored as computer files and then built to order. The consortium has also produced test parts for six different aerospace companies and is being invited to develop more for other sectors.
RAPOLAC project coordinator Dr Rosemary Gault of the Advanced Manufacturing Research Centre (AMRC), Sheffield University, commented: "The main objective of RAPOLAC was to validate the SMD for use within aerospace and develop the process to the point where it can reliably and re-peatedly be used in manufacturing."
"The SMD process we have demonstrated can reduce by 60% the lead-time needed to produce new parts through the elimination of the tooling and prototyping stages. This could be of particular benefit to SMEs working on small batches of parts. The technology has the potential to allow smaller firms across the regions of Europe to diversify into the aerospace market and offer competitively priced precision parts."