Method for Measuring the Distance Between a Workpiece and a Machining Head of a Laser Machining Apparatus

摘要

According to a method for measuring the distance between a workpiece and a machining head of a laser machining apparatus, a machining head is provided, which has a housing that has an interior and an opening for emergence of the laser radiation from the machining head. The laser radiation is directed on to the workpiece, after it has passed through the interior and the opening. An object beam is directed on to the workpiece by a light source of an optical coherence tomograph in such a manner that the object beam passes through the interior and the opening before being incident upon the workpiece. In addition to the object beam, a measuring beam passes through the interior. The measuring beam is used to compensate falsifications of the measured distance that have been caused by pressure fluctuations in the interior. The measuring beam in this case may be reflected at a reflective face that is formed on an inner face of an outlet nozzle that comprises the opening, which inner face delimits the interior.

主权项

1. A method, comprising the following steps:
a) providing a machining head of a laser machining apparatus that is configured to machine a workpiece by means of laser radiation, wherein the machining head comprises a housing that has an interior and an opening configured to emit the laser radiation, b) directing the laser radiation on the workpiece after the laser radiation has passed through the interior and the opening; c) generating an object beam by means of a light source of an optical coherence tomograph, and directing the object beam on the workpiece in such a manner that the object beam passes through the interior and the opening before being incident upon the workpiece; d) detecting a reflection of the object beam from the workpiece; e) superimposing the reflection of the object beam with a reference beam generated by the light source of the coherence tomograph; f) determining the distance between the machining head and the workpiece from an interference signal obtained by the superimposition in step e);wherein a measuring beam, which passes through the interior in addition to the object beam, is used to compensate falsifications of the measured distance that have been caused by pressure fluctuations in the interior.