|
6300 |
|
Friday, June 12, 2020, Hall G2 12:20 PM Laser Cladding |
|
Pulsed laser influence on temperature distribution during laser metal deposition |
|
Marius Gipperich* / Fraunhofer Institute for Production Technology IPT, Germany Thomas Bergs / Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University, Germany Jan Riepe/ Fraunhofer Institute for Production Technology IPT, Germany Day Robin/ Fraunhofer Institute for Production Technology IPT, Germany Kristian Arntz/ Fraunhofer Institute for Production Technology IPT, Deutschland |
|
Wire-based Laser Metal Deposition (LMD-w) is a suitable manufacturing technology for a wide range of applications such as repairing, coating or additive manufacturing. It combines comparatively high deposition rates with the use of an easily manageable wire feedstock allowing a quick and contamination-free handling in contrast to the powders used in LMD with powder (LMD-p). Employing a pulsed wave (pw) laser additionally to the continuous wave (cw) process laser has several positive effects on the LMD process stability. While the pressure caused by the pw-induced evaporation allows changing the shape of the beads, the plasma is also assumed to influence the cw-absorption and thus the temperature distribution in the workpiece. In this contribution, several experiments are carried out in order to characterize the heat input during the dual beam process. In the first setup, small aluminium and steel disks are heated up either by only cw or by combined cw and pw radiation. The absorbed energy is then determined by dropping the samples into water at ambient temperature and measuring the water's temperature raise. In a second experiment, the temperature distribution in the deposition zone under real process conditions is examined. For this, measurements on the top of the workpiece by an IR camera and on its bottom by optical backscattering reflectometry are conducted. The aim of this work is to achieve a deeper understanding of the physical phenomena acting during dual beam laser metal deposition and to deploy them selectively for a better and more flexible process control. |