Device and method for calibrating an irradiation system of an apparatus for producing a three-dimensional work piece

An apparatus for producing a three-dimensional work piece, comprising:

• an irradiation system;
• a carrier which, during normal operation of the apparatus, carries a raw material power to be irradiated;
• and
• a device for calibrating the irradiation system of the apparatus, the device comprising:
• a control unit adapted to control the irradiation system so as to irradiate a radiation beam onto an irradiation plane according to a calibration pattern, and
• a sensor arrangement adapted to be arranged in the irradiation plane and to output signals to the control unit in response to being irradiated with the radiation beam according to the calibration pattern,
• wherein the control unit further is adapted to:
• generate a digital image of an actual irradiation pattern produced by the radiation beam incident on the sensor arrangement based on the signals output by the sensor arrangement,
• compare the digital image of the actual irradiation pattern with a digital image of a reference pattern so as to determine a deviation between the actual irradiation pattern and the reference pattern, and
• calibrate the irradiation system based on the determined deviation between the actual irradiation pattern and the reference pattern,
• wherein the sensor arrangement is integrated into the carrier which, during normal operation of the apparatus, carries the raw material powder to be irradiated, or
• wherein the sensor arrangement is integrated into a calibration carrier which is adapted to replace, during calibrating the irradiation system, the carrier which, during normal operation of the apparatus, carries the raw material powder to be irradiated.