Building on strong foundations

With multiple arc welding power sources and robots available, OCAS is moving ahead.

OCAS has longstanding experience in the field of welding, covering a wide range of materials (but with a focus on steels), applications and welding processes. For example, the introduction of many steel grades and materials into industry has been supported by the welding guidelines developed at OCAS. Similarly, very specific weld tests (e.g. on different forms of weld cracking) and various welding pre-qualification campaigns (e.g. for offshore steels) are often run. All of these have given the welding team a solid and wide-ranging experience which is now being applied to WAAM.

The equipment available for WAAM in the welding laboratory in Gent includes six-axis robot arms fully integrated with several arc welding power sources. Each robot arm has a reach sufficient to allow in principle the manufacture of components roughly up to a couple of cubic metres in size. Furthermore, a software update is foreseen to allow more efficient manufacture of even complexer components. For the arc welding process, all common options are available in-house. For Gas Metal Arc Welding (GMAW), the process of choice for WAAM, digital inverter power sources from several manufacturers are available, meaning many of the modern process variants can be tried. In addition, robotic Gas Tungsten Arc Welding (GTAW) and Plasma Arc Welding (PAW) with or without wire feed can be run on the robots, allowing for example also partial (surface) remelting of components. Hardware extension is foreseen, which would allow the simultaneous addition of filler wire and powder, further extending the capabilities for creating bespoke compositions, even ones that can vary within the part.

The experimental facilities are supported by OCAS’ small-scale filler wire manufacturing as well as extensive numerical simulation and prediction capabilities. The latter cover all aspects of welding from prediction of weld bead shape and dimensions to microstructural properties and thermally induced stresses and distortion.

“The OCAS welding team’s solid and wide-ranging experience is now being applied to wire & arc additive manufacturing, for which multiple arc welding power sources and robots are available.”

Christoph Gerritsen, Senior Research Engineer Welding, Applications & solutions department, OCAS