This study compares three different optical sensors as non-contact wire feed rate (WFR) sensors for directed energy deposition-laser beam (DED-LB) with wire processes. Accurate WFR measurement is essential to maintaining process stability, minimizing defects, and enabling higher deposition rates, which are critical for improving the competitiveness of DED-LB with wire in additive manufacturing. The research focuses on the comparison in performance of three high-end optical sensors to understand which sensor (if any) is best suited for the application.

Multiple experiments evaluated the sensors under diverse conditions. Each set of experiments recreated one challenging scenario that the sensors will come across in DEDLB with wire processes. Firstly, the performance of the sensors was tested on low surface roughness wire. Secondly, the effect of shiny metals, like stainless steels, was analyzed. Finally, the effect of distance increments was investigated to understand how sensitive the sensors are. With these tests, a promising candidate for a wire feed sensor in DED-LB with wire was identified.