Development of a Coaxial Laser Wire System for the Additive Manufacturing of Functional Graded Materials using Direct Energy Deposition

Laser wire Direct Energy Deposition (L-DED) is a manufacturing process capable of producing additively generated structures as well as repairing and coating of surfaces. The use of a coaxial system technology enables a direction-independent application of the weld deposit. For coaxial Laser Double-wire DED (LD-DED), a processing head with a centric wire feed for two wires has been developed. Using three single beams with a maximum output power of 220 W each and a wavelength of 970 nm, a combined focus point of 1.6 mm in diameter is realised. The single beams are guided using an optical fibre for each laser beam source. The advantages of the system are the small footprint, the individual control of the single laser beams and the ease of conversion to other applications. This paper describes the development of the coaxial laser-processing head for the Additive Manufacturing that is capable to produce functionally graded structures.