Robotic manufacturing by shaped metal deposition: state of the art

Purpose - The purpose of this paper is to provide an overview of shaped metal deposition (SMD). SMD is an additive manufacturing process which uses a robotic cell to create fully dense, near-net shape, metallic parts directly from computer-aided design files. Design/methodology/approach - Research into optimising the SMD process was carried out as part of the 6th Framework RAPOLAC project. This included developing both robotic and weld models, creating a weld controller, and using a design of experiments approach to optimise parameters based on the resultant component microstructure and material properties. Extensive metallurgical analysis and mechanical testing was carried out. Findings - A mechatronic model of the robot was produced and integrated with a novel controller to allow parts to be manufactured with little or no operator intervention. Computational models of the temperature field, microstructure, strain and stresses that occur during deposition were also developed. Variation in weld parameters was linked to part microstructure and mechanical properties. Research limitations/implications - This research focussed on a common titanium aerospace alloy (Ti-6A1-4V). Practical implications - The SMD process is applicable to a variety of parts in a range of industrial sectors. It is cost-effective for low-volume parts and prototypes, but it is envisaged that its main use will be to add material to previously forged or cast components and therefore SMD will allow companies to reduce both the size of forgings and material waste. SMD as a repair technique is also being investigated. Originality/value - The paper provides a summary of the latest advances in robotic manufacturing by SMD.