7. Directed energy deposition (DED)
This technology can be considered as a variation of the Electron Beam Deposition, or other deposition technologies involving laser beams, discussed in a previous post. It is often used as a way to repair metal cracks by adding metal that becomes fused with the one existing, keeping the strength of the original part, as an example to fix cracks in fan’s turbine. It can also be used
to add ceramic materials and mixture of metal and ceramics. Depending on the heating technology adopted (laser or electrons beam) it has to operate in specific environment (inert gas to avoid oxygen contamination when using laser heating, vacuum when using electron beams).
The interest in DED is the possibility of creating alloys on the fly, at the time an object is being 3D printed.
A further strong point of DED is the lower cost of the whole process with respect to normal Laser Powder Bed and E-beam Powder Bed (see graphic).
The word “Energy” in DED emphasises the significant amount of energy (heat) involved and this intense heating can create (does create) stress in the underlining metal structure. This requires a continuous monitoring of the process and when needed the stopping of the printing to let the substrata recover from the stress.