Analysis of response signals to minimally invasive laser modulation in laser cutting

Abstract

AbstractA robust real‐time monitoring system for the laser cutting process has been targeted by researchers and users for several decades without significant breakthrough. The use of coaxial photodiodes provides a cost‐effective and straightforward system; however, the assessment of the process state based on the spatially integrated detected signals can lead to misinterpretation due to the numerous and interacting parameter dependencies of the signals. To obtain a clear correlation of the signals to the process state, minimally invasive laser modulation stimulates characteristic state‐dependent response signals. In this study, the response signals to a laser power modulation are analyzed in the visible and infrared range. Furthermore, a spatially and temporally resolved analysis of the process response is enabled by means of high‐speed videography. This provides a comprehensive understanding of the process state in terms of temperature and geometry response to the modulation and offers a reliable exploitation of process emissions for real‐time monitoring and control applications.