Method and device for conducting and monitoring a machining process of a workpiece

The invention relates to a method for conducting and monitoring a machining process of a workpiece (10), in particular a welding process for joining the workpiece (10) to a further workpiece (10), by means of a high-energy machining beam (14), wherein the method comprises the following steps: generating a high-energy machining beam (14); projecting and/or focusing the machining beam (14) onto the workpiece (10), wherein, in accordance with a machining control signal, different machining regions of the workpiece (10) are machined; generating a measurement beam (16) by means of an optical coherence tomograph (18), wherein the measurement beam (16) is able to be coupled into the machining beam (14); determining measurement points (20) during the machining process by means of the optical coherence tomograph (18) using the measurement beam (16), in accordance with a measurement control signal; obtaining at least one external signal which is based on a measured variable and which is independent of a processing of the machining control signal and of the measurement control signal; generating an evaluation on the basis of the measurement points (20) and of the at least one external signal, which evaluation comprises a comparison of the measurement points (20) with at least one threshold value; monitoring the machining process on the basis of the evaluation.The invention relates further to a correspondingly configured device for conducting and monitoring a machining process of a workpiece (10).