This paper provides first results of a contact-free measurement system for monitoring the material flow in series production which has been under investigation for more than one year. An inductive proximity sensor with analog output was used to measure its own sheet metal coverage. Multiple sensors were integrated in the blank holder without affecting the deep drawing process. The robustness of the monitoring principle was assessed under series production conditions by using optical measurement equipment. This paper describes the basic information of the inductive measurement, the comparison of the inductive and optical measurement results and analyses correlations between the sensors.