Additive manufacturing by means of parametric robot programming

Abstract

3D printing or additive manufacturing (AM) is now becoming a common technology in industry. The research activities in this area are constantly increasing, because with the high level of automation and the possibility to produce individual and complex structures, the advantages of additive manufacturing are promising. Most materials used in the construction industry can be used for additive manufacturing, for example steel and concrete. The print head (for example, a welding torch in the AM of steel) is mainly led by industrial robots, whose movements must be transferred from the 3D geometry files to be manufactured. In contrast to all-in-one systems, where hardware, software and printed material are coordinated, most robot-based AM systems are made of components from different manufacturers and branches. The objects to be manufactured are complex and the manufacturing parameters, which significantly influence the geometry and quality of the manufactured part, are manifold. This makes the workflow from the 3D model to the finished object difficult, especially because it is almost impossible to predict the exact manufactured structure geometry or layer height (which would be indispensable for accurate slicing). During the manufacturing process, deviations between the target and actual geometry can occur. In this paper, parametric robot programming (PRP) is presented, which allows flexible motion programming, and a quick and easy reaction to deviations between target and actual geometry during the manufacturing process. Complex geometries are divided into iso-curves whose mathematical functions are determined by means of polynomial regression. The robot can calculate the coordinates to be approached from these functions itself. This allows a simple adjustment of the manufacturing coordinates during the process as soon as target-actual deviations occur. The workflow from the file to the manufactured object is explained. The principle of PRP is transferable and applicable to all robot manufacturers and all conceivable printing processes. In the following article, it will be presented using wire + arc additive manufacturing, in which welding robots or portals can be used to produce steel structures with high deposition rates. Furthermore, the project "AM Bridge 2019" is presented, in which a steel bridge was manufactured in situ over a little creek and the presented PRP was applied.

Design for Additive Manufacturing: Recent Innovations and Future Directions

“…The failure mechanisms of the hybrid printed lattice compared to lattices produced using DLP resulted in a higher maximum load achieved with a smoother load-displacement response. Parametric programming for robots has been used to produce large-scale steel constructions [157]. Programmed robots have capabilities for printing with steel, concrete, or clay, and the parametric programming approach facilitates automatic calculations of z-coordinates, requires small memory capacities, and enables the efficient scaling of objects.…”

3D‐gedruckte Stützen mit außergewöhnlicher Geometrie

“…Ein zentrales Element für die Anpassung der Schweißbahnen anhand der aufgezeichneten Informationen ist die parametrisierte Roboterprogrammierung (PRP). Dieses Verfahren, das bereits in [21] dargestellt wurde, unterscheidet sich von der konventionellen Roboterprogrammierung dadurch, dass die Koordinaten mittels mathematischer Funktionen erzeugt werden, die durch die während des Druckvorgangs aufgezeichneten Informationen definiert sind. Da beim konventionellen Slicing (Bild 5a) jede einzelne Koordinate vorberechnet und als Codezeile gesendet werden muss, sind die von PRP erzeugten Dateien (Bild 5b) in den meisten Fällen deutlich kleiner als konventionelle.…”

WAAM-Fabricated Laminated Metal Composites

“…Feucht et al [14,15] investigated the welding process of steel-based WAAM and explored the use of parametric robot programming which enables manufacturing of structures without an exact prediction of layer geometry.…”