Patent ID: 8803073

Claim:
A method of calibrating a CO 2 laser of an apparatus for generatively manufacturing a three-dimensional object, wherein the apparatus layerwise applies a powdery or liquid building material onto a support of the apparatus or a previously applied layer, the applied layer defining a working plane, and irradiates the building material by the CO 2 laser with energetic radiation at locations corresponding to the object so as to solidify the building material at these locations, the method comprising the following steps: arranging an image converter plate in, or in parallel to, the working plane, wherein the image converter plate outputs detectable light when the CO 2 laser irradiates predetermined positions of the image converter plate with the energetic radiation, wherein the image converter plate can convert CO 2 laser light into visible light to near-infrared light and the image converter plate consists of (i) a substrate which permits detectable light to pass through, (ii) an aperture mask in which apertures are located corresponding to the predetermined positions of the image converter plate, and (iii) an image converter material, and the aperture mask is arranged at an upper side of the image converter plate and the image converting material is arranged between the substrate and the aperture mask; scanning the image converter plate by the CO 2 laser; detecting the detectable light by a light detector; determining coordinates of the CO 2 laser when the detectable light is detected; comparing the determined coordinates with predetermined reference coordinates; and calibrating the CO 2 laser on the basis of a deviation between the determined coordinates and the reference coordinates.