Method for calibrating at least one scanning system of an sls or slm installation

A procedure for calibration of at least one scanning system (6a/6b) of a laser sinter (SLS) or laser melt (SLM) facility (1) in which by means of the at least one scanning system (6a/6b) the pencil beam (4) of at least one beam source, in particular of a laser (3), is directed onto a construction field (2) in order by means of a construction process to melt or fuse a construction material capable of sintering or melting and thus through its cooling selectively to solidify characterized by the following calibration and procedural steps:

• Generation of at least one line pattern, particularly of a scanning grid (8a/8b), through the at least one scanning system (6a/6b) on a surface at the level of the construction field (2), whereby
• the line pattern is projected either on a surface element showing the line pattern temporarily or constantly, whose image during the generation of the line pattern(s) is read or subsequently recorded by a calibrated camera (9) configured over the construction field (2) and read into a memory (7), or
• the line pattern(s) is (are) projected on the upper surface of the calibration plate already provided with an applied specified line pattern and the deviation of the line pattern produced by at least one scanning system (6a/6b) from the specified line pattern is recorded by a camera (9) configured over the construction field (2) and read into a memory (7);
• execution of a field correction of the line pattern by calculation of correction data regarding in essence the one scanning system (6a/6b) which data contain the necessary information for correction of any distortions of the line pattern, especially of the scanning grid (8a/8b) and
• subsequent correction of the line pattern for avoidance of imaging errors.