DEVICE FOR SETTING A FOCUS POSITION OF A LASER BEAM IN A LASER MACHINING SYSTEM, LASER MACHINING SYSTEM COMPRISING THE SAME, AND METHOD FOR SETTING A FOCUS POSITION OF A LASER BEAM IN A LASER MACHINING SYSTEM

摘要

A device is provided for setting a focus position (z) of a laser beam in a laser machining system. The device comprises a computing unit configured to calculate a time-dependent value zt of the focus position (z), wherein the computing unit calculates the time-dependent value zt of the focus position (z) based on a first parameter and a second parameter, wherein the first parameter indicates a magnitude A of a laser-power dependent focus shift per power unit and the second parameter indicates a time constant τ of a change in focus position due to a thermal lens by a factor of 1/e, and a control unit configured to use a mechanism for setting the focus position (z) to set the focus position (z) of the laser beam based on the time-dependent value zt of the focus position (z).