Process monitoring in laser beam cutting on its way to industrial application

In the past a variety of scientific investigations has proven, that during laser beam cutting optical emissions from the process correlate with properties of the cut kerf and thus can be used to characterize the quality of the machined parts. Laser beam cutting has been well established in many fields of industrial use and has reached a high grade of productivity and flexibility. Due to this, modern on-line techniques for process monitoring in laser beam cutting have to be as fast and flexible as today's laser beam cutting machines. The objective of the work being presented is to provide useful support for the machine personnel and to enable automatic quality monitoring even in case of a small number of units to be cut. The paper introduces some general considerations on the demands of process diagnostics in laser beam cutting and presents ''hardware''-tools which have been developed during an industry-university-partnership. The equipment can be adapted to ail kind of cutting machines and measures the optical emission from the process within the cutting head. The crucial thing of the work is still the adequate application of analyzing and visualization techniques to extract significant information from the measured signals. Here, this is done by relating the information derived on-line from the process to the geometry of the cut contour. It makes visual quality inspection much easier and more effective: Sections of the processed parts with minor cut quality are indicated to the personnel as scrap or at least as to be checked visually. A first approach of integrating such a system into a laser beam cutting machine is presented and discussed.