Established and Adapted Diagnostic Tools for Investigation of a Special Twin-Wire Arc Spraying Process

In the LDS® (Lichtbogendrahtspritzen) process, a twin-wire arc spraying (TWAS) process developed by Daimler AG, the gas injection and feed to the arc play a crucial role in separating the molten particles from the wire ends. This paper describes an investigation of the gas and particle behavior according to individual LDS® process parameters. Coating problems are not considered. The measurements are separated into two different parts: “cold” (without arc and particles) and “hot” (with arc and particles). The results provide the first detailed understanding of the effect of different LDS® process parameters. A correlation between the gas parameter settings and the particle beam properties was found. Using established and adapted diagnostic tools, as also applied for conventional TWAS processes, this special LDS® process was investigated and the results (gas and particle behavior) validated, thereby allowing explanation and comparison of the diagnostic methods, which is the main focus of this paper. Based on error analysis, individual instabilities, limits, and deviations during the gas determinations and particle measurements are explained in more detail. The paper concludes with presentation of the first particle-shadow diagnostic results and main statements regarding these investigations.