“Investigations Of A Pulsed DC Arc Spray Process” – Lecture on a pioneering thermal spray technology
Orlando, Florida, USA, May 2018. The INTERNATIONAL THERMAL SPRAY CONFERENCE AND EXPOSITION (ITSC, May 7-10, 2018) is the world's foremost international conference and exposition for thermal spray technologists, researchers, manufacturers and suppliers and took place this year in Orlando, Florida.
Mr. Stefan Brumm (Technische Universitaet Chemnitz, Institute for Machine Tools and Production Processes (IWP) and Mr. Jan Morgenschweis from ELMA-Tech gave a lecture on DC thermal spray technology and reported on new investigations of a pulsed DC arc spray process.
Modern machines for arc spraying enable to control the melting-off behavior of the electrodes and influence thus the layer quality positively by modulation of the arc current.
The paper of Brumm, Morgenschweis et al. was a contribution for an investigation of a pulsed DC-process in which electrical parameters such as pulse frequency f, pulse voltage UP, basic current Igrd, pulse time tP, control speed VDyn, and the static slope of the characteristic curve in the pulse phase nP have been varied.
By means of the respective current and voltage profiles the influence of the electrical parameters to the process performance and stability as well as process limits have been shown. The melting-off behavior of the electrodes in the DC pulse process was analyzed by means of high-speed recording. The movement of the modulated electric arc in the process, the particle detachment and distribution and the process parameters have been compared to a conventional arc spraying process.
Finally, selected samples have been evaluated metallographically to determine the influence of the pulse parameters on the layer quality. The investigations on the pulsed arc wire spraying demonstrated both a stable process characteristic and improved coating results compared to conventional arc wire spraying.