As knowledge and experience of arc directed energy deposition (DED) process grows, it is becoming understood that the approach to building parts is not simply stacking weld on weld. The interactions between geometrical features within layers, the methodology of bead placement within a layer and how separate layers interact with each other have all been shown to have an effect on the output of the process. The thermal field generated affects the cross section of the newly deposited bead and the evolution of the microstructure within it. Similarly, the welding world’s approach of using a fixed set of process parameters has also been shown to result in a variable output in terms of geometry, regularity and unusual microstructural evolution. For these reasons, it is felt that the future of arc DED will be as a digital process where the part and its properties requirements are processed through an integrated modelling, simulation and computer aided engineering (CAE) package and the manufacturing process in terms of feedstock chemistry, deposition path and deposition parameters is generated to take account of all the complexities of the physical process.
This project will develop knowledge of deposition process parameters and develop methods to place a consistent bead cross section during manufacture of complex geometric features using arc DED. Additionally, during processing, the process parameter effects and thermal fields will be measured and used to provide input to the linked microstructure project, other modelling and simulation efforts and the linked monitoring and non-destructive testing project. Two main tasks will be performed:
Activity 1 – Development of critical deposition parameters and control methods;
Activity 2 – Deposition using developed variable input deposition process, including special chemistry feedstock and on-line monitoring and testing methods.