The wire arc additive manufacturing (WAAM) technology is a directed energy deposition process that uses an arc welding equipment to melt and continuously deposit material in wire form.
This technology allows the bead-by-bead manufacture of 3D parts, adding layer on layer, with no size limit (the limit depends on the working space of the welding equipment), and with high deposition rates (up to 4 Kg/h for steels, and 2 Kg/h for aluminium and titanium alloys).
MIG-MAG, TIG and plasma welding sources can be used as preferred welding process. Additionally, simultaneous melting and deposition of several wires can be performed, multiplying the aforementioned deposition rates by 2.
The technology allows to work with traditional filler metals, thus drastically reducing the material costs (up to 10 times less than the same alloy in powder format) and simplifying its handling. Likewise, the process can be carried out in robotized cells and traditional automatic welding systems, which minimizes investment and training costs.
The main limitations lie both in the need to apply final machining to the part as a near-net-shape part is obtained, and in the control of residual stress and distortions that are generated, above all in massive parts.
This technology is currently of interest in different sectors, but particularly aerospace, naval, automotion, moulds and dies, energy and construction (architecture). Applications with high added value materials where the buy-to-fly ratio is very high are particularly suitable. In these cases, it is possible to achieve reductions of 70 to 90% in material consumption, which justifies its use as an alternative technology to traditional manufacturing processes such as milling or lathing.