Cheaper and ‘greener’ manufacture of aircraft parts
Shaped metal deposition (SMD) is a promising manufacturing process for prototyping and one-off parts patented by Rolls-Royce and licensed to the University of Sheffield. It allows complex metallic parts to be produced directly from digital specifications (a computer-aided design (CAD) file). In addition, it minimises tooling and finishing and produces little to no harmful emissions. However, it has not been commercialised due to its dependence on manual control by a skilled technician and to lack of understanding of material properties for the parts produced. SMD’s potential for significant time, materials and cost savings when making complex parts is expected to make it particularly attractive to the aircraft industry where currently 90 % of material is removed. European scientists initiated the ‘Rapid production of large aerospace components’ (Rapolac) project to develop better automation and control and SMD process models for a wider variety of materials, making it directly applicable to aircraft manufacture. Overall, the consortium developed stable parameters for welding a common titanium alloy based on characterisation of its properties and automation of deposition. The stable parameter window is paramount to repeatability, reliability and quality of the finished part. Rapolac scientists also compared the cost and environmental benefits of SMD to traditional manufacturing techniques for numerous low-volume aerospace parts made from the selected material. The SMD process resulted in a decrease in production lead time from 9 months to 1 month, half the energy consumption of traditional methods and a 20 % decrease in harmful emissions. The Rapolac project made important enhancements to SMD technology for producing low-volume or prototype parts with a focus on the aerospace industry. Significant decreases in production time, energy consumption and raw material waste will lead to important cost savings. Together with reduced emissions, Rapolac technology should make it easy to get aerospace manufacturers, investors and the public on board.
