Calibration Method for Constant Strands of Material with Robotassisted Concrete Extrusion (2021-09)¶

Robot-assisted concrete extrusion is a new type of additive manufacturing process in which the strategy, material and conveyor system must be specifically coordinated. In particular, the real shape of the extruded material strand is subject to significant fluctuations along the starting point through the main extrusion phase to the switch-off process due to local over- and under-extrusions, which usually do not meet the quality specifications. In this thesis, a calibration procedure for extrusion processes is developed, adapted and tested on the software side and the effects of the feed rate on the component quality are investigated. For this purpose, different calibration methods of current additive manufacturing processes were considered and evaluated with regard to their usability for the extrusion of mineral suspensions. Based on this, a generally valid calibration procedure was developed in theory and implemented in practice. In the functional tests carried out, the calibration procedure reduced process preparation, increased process reliability through stabilized extrusion and shortened the cycle time. This increase in productivity in additive manufacturing leads to positive economic effects and also makes applications for high-strength lightweight structures in the construction industry more attractive. It also enables the series production of free-form modular designs.