Presently, large parts are made by machining from solid, or from castings which require large moulds. In aerospace, where weight is critical, often more than 90% of the original material is removed to produce the final part. By growing the part from the base up, and by adding protrusions only where necessary, SMD would reduce the raw material used and hence the cost of the part.
For SMD to be validated for aerospace parts the material properties produced by parameter combinations must be fully understood and reproducable. Adding feedback to the deposition process and automating it will give aerosapce companies the confidence to use SMD in manufacture.
The overall aim of RAPOLAC is to produce prototype aerospace parts using the SMD process to validate its utility in manufacturing large parts from a variety of materials.Current take-up is limited because:
- Good weld parameters vary according to material, substrate and part geometry and size;
- Material properties of the finished parts are not well understood;
- The process is labour intensive and relies upon the skill of the operator to achieve good material properties and surface finish;
- The benefits of SMD over more traditional processes are not clear.
Research will focus on controlling the process, maintaining the quality of the microstructure and developing process models of the 8-axis system to optimise motion control.