Additive manufacturing apparatus and calibration method thereof

An additive manufacturing apparatus, comprising:

• a material layer former forming a material layer on a molding region that is a region in which a three-dimensional molded object is formed;
• an irradiation device comprising at least one laser source that outputs a laser beam, and a plurality of scanners that respectively scan laser beams and irradiate the material layer to form a solidified layer;
• an imaging device having an imaging sensor and configured to image the molding region;
• and
• a controller controlling the material layer former, the irradiation device, and the imaging device,
• wherein the controller
• controls the irradiation device to scan the laser beams with each of the plurality of scanners with respect to a plurality of target positions on a calibration plate installed on the molding region, and form a plurality of irradiation traces having different shapes for each of the plurality of scanners,
• controls the imaging device to simultaneously image the plurality of irradiation traces formed with respect to a same target position among the plurality of target positions,
• specifies a plurality of irradiated positions of the laser beams scanned by each of the plurality of scanners based on the plurality of irradiation traces imaged by the imaging device, and
• generates correction data that specifies a deviation amount at any point of a laser coordinate system related to each of the plurality of scanners based on the plurality of irradiated positions specified.