The use of welding for creating free standing shapes was established in Germany under the process named Shape Welding in the 1960's. This led to companies such as Krupp, Thyssen, and Shulzer developing welding techniques for the fabrication of large components of simple geometry, such as pressure vessels. Other work in this area has been undertaken by Babcock and Wilcox under the process name Shape Melting, that was used mainly for building large components made of austenitic materials. Also, work by Rolls-Royce has centered on investigating 3D welding as a means of reducing the waste levels of expensive high performance alloys that can occur in conventional processing. They have successfully produced various aircraft parts of nickel-based and titanium-based alloys.
Research work on 3D welding has been in progress at the University of Nottingham, UK, University of Wollongong, Australia, and Southern Methodist University, Dallas, Tex. Two new research groups, one from Korea and another consisting of researchers from Indian Institute of Technology Bombay and Fraunhofer Institute of Production Technology and Automation presented their conceptual ideas of combining a welding operation with milling. The Korean research group is proposing to combine welding and 5-axis CNC milling for the direct prototyping of metallic parts. The other research group from Germany and India is proposing to combine welding with 2½axis milling, where complex shapes of the layers are obtained by using angle cutters. The brazing process is proposed to deposit the masking material at the edges of each layer in order to allow the formation of overhangs.