METHOD FOR MEASURING PHASE BOUNDARIES OF A MATERIAL DURING MACHINING WITH A MACHINING BEAM USING ADDITIONAL ILLUMINATION RADIATION AND AN AUTOMATED IMAGE PROCESSING ALGORITHM, AND ASSOCIATED DEVICE

摘要

The invention relates to a method for measuring phase boundaries of a material during the machining of a workpiece (12) with a machining beam (1), especially with a laser beam (1), and a device that is embodied in such a way as to carry out the method. According to said method, during the machining, a machining region (13) containing the impact point of the machining beam (1) on the workpiece (12) is illuminated at least approximately coaxially to the machining beam (1) by means of additional optical radiation (2). Radiation (3) reflected by the machining region (13) is detected, parallel to an incidence direction of the optical radiation (2) or at a small angle thereto, by means of an optical detector with local resolution, in order to obtain an optical reflection pattern of the machining region (13). From the optical reflection pattern, a course of at least one liquid/solid phase boundary in the machining region (13) is then determined in an automated manner by means of an image processing algorithm on the basis of a transition from a region containing a large-surface homogeneous area and a region containing a plurality of small-surface homogeneous areas in the optical reflection pattern.