As the leading industry platform for additive manufacturing and industrial 3D printing, Formnext is the international meeting point for the next generation of intelligent industrial production.
Fraunhofer joint booth
A measuring system for automated characterisation of the powder nozzle during laser powder build-up welding
While tool calibration is state of the art in conventionally used ablative processes such as milling, in laser powder buildup welding it is still a great challenge. The Fraunhofer Institute for Material and Beam Technology IWS developed the measuring device ”LIsec” to solve this challenge and to move the limits to technical feasibility. The abbreviation stands for ”Light Section” and already reveals the principle: A measuring laser scans the powder fl ow after leaving the nozzle. A right-angled camera records light sections through the powder and forwards them to an analysis software. The three-dimensional distribution of the powder fl ow can be calculated with high precision. This allows signifi cantly simplifi ed quality control and provides information on the wear degree of the powder nozzle.
For example, it can be used to repair damaged or worn turbine blades on aircraft in higher quality and more reliably than before. In this respect, the measuring device can contribute to greater safety and lower maintenance costs in aviation. The Dresden institute is already working on the industrial implementation of the technology with several well-known international companies and research institutes.
Increased process reproducibility through permanent monitoring of the powder mass fl ow rate
For a stable and therefore reproducible process, in addition to process shielding with ”COAXshield” and the qualifi cation of the powder cone by the »LIsec«, it is also necessary to know all input variables exactly and to control them, if necessary. Especially the continuous measurement of the fed powder quantity has been a great challenge so far.
The ”POWDERscreen” sensor, which is currently being developed at Fraunhofer IWS as part of an EU research project, detects exactly when and how much of the different particles are fed into the melt pool. The fed powder mass can be calculated exactly on this basis. As a result, it is possible to detect fl uctuations in the particle mass fl ow and report them to a downstream controller.
Not only does this signifi cantly increase the process reliability, but it also enables several different powders to be mixed in a targeted manner during the welding process. A discrete-time measurement of the powder mass fl ow also signifi cantly increases the process digitization level and provides data for creating a digital twin of the created component.
Video: Tailored solutions in thermal surface technologies (YouTube)
Hardening, protecting and repairing – processes and system technology for laser beam hardening and laser cladding
Fraunhofer Institute for Material and Beam Technology IWS