In order to gain “First Time Right” parts in laser additive manufacturing processes with cw sources sensor technology is required not only with high temporal and spatial resolution for evaluating the result of the treatment, the measurement has to provide information which can be directly implemented in a closed loop control. Especially in the context of Industry 4.0, digitalization and predictive maintenance reliable sensors get much more into focus. A major drawback of this photon-material interaction with respect to the acquisition of trustworthy measurement data from the interaction zone is the presence of intense process emissions and steep temperature gradients. In DMD processes with powder the material itself also is a source of noise when it comes to sensors coaxially mounted onto the processing head.

Common devices used as sensors for process monitoring in additive manufacturing are CMOS/IR cameras or photo diodes which help to get an idea of the resulting quality but the acquired data can hardly be correlated with the “printed” geometry.

A group of scientists from Siemens, Precitec and RWTH Aachen developed a solution for accurate and controlled DMD processes based on the OCT sensor and the Siemens SINUMERIK® machine control. By controlling the feed rate of the process “First Time Right” is not a pious hope anymore.