Research Summary Report of A07

Prof. Dr.-Ing.  Jonas Hensel                Project Leader, jonas.hensel@mb.tu-chemnitz.de

Technische Universität Chemnitz (TUC), Institute for Joining and Assembly Technology

A07 focusses on advancing WAAM technology for large structures and on-site applications by addressing material interactions and incorporating manufacturing constraints through a Holistic Design Framework (HDF). A “Learning-by-Printing” approach will enhance the process via online decision-making to mitigate geometric deviations, process irregularities, and heat accumulation. Additionally, research on buckling behaviour will investigate geometric imperfections, load-deformation, load-bearing cross sections, and ductility. The development of a Digital Twin will integrate design, manufacturing, geometry, and performance data for virtual component testing. Finally, sustainability will be examined through Life Cycle Analysis, with improvements guided by Life Cycle Design principles.

Summary

The collection of data from DED-arc and the subsequent generation of a database is a fundamental step in the creation of a digital shadow. For this reason, a multi-sensor system was developed that is able to monitor electrical process parameters and temperature of the part with a thermal camera utilizing a pyrometer. This information is collected as a function of time and robot position. The system was successfully tested in the manufacture of a pipe, see Fig 1. However, in order to create a model and analyse the effects of the measured factors on part geometry, the layer’s height and width must be determined as well. For this reason, an online geometry scans sensor needs to be incorporated.

Current state of research

To enable adaptive path planning, to control layer dimensions, and address unforeseen events, measuring layer height and width is essential. Therefore, a laser profile sensor is integrated into the DED-Arc process robot. However, in the first step, the sensor is designed to efficiently scan the work area in one direction, providing data for simple planar layer geometries. By processing this data, the seam height and width are determined, while the average part height is calculated in idle time between layers. This allows the development of an algorithm to automate the robot, ensuring a constant contact-tip-work-distance (CTWD). The aforementioned algorithm allows to ensure the final dimensions of the part, e.g. as-designed will equal as-built geometry.