Three-dimensional object building apparatus and method for building three-dimensional object

A method for building a three-dimensional object, comprising:

• a step for providing a powder delivering unit, a powder flattening device, a light beam radiating unit and a cover structured integrally with one another such that these are movable in three-dimensional directions, wherein
• the powder delivering unit delivers a powder on an object building area,
• the powder flattening device flattens a surface of the powder delivered from the powder delivering unit to form a powder layer,
• the light beam radiating unit is disposed above the object building area and radiates a light beam on the powder layer to sinter or melt solidify the powder for building the object,
• the cover surrounds a space above an area of the powder layer that is smaller than the object building area around a radiation of the light beam;
• a one-layer building step comprising
• a powder layer forming step for moving the cover in lateral direction so that a powder of amount corresponding to the moved distance is delivered by the powder delivering unit below the cover and flattened by the powder flattening device,
• an object building step for radiating a light beam on the layer flattened in the powder layer forming step for building the object,
• wherein one powder layer is built by repeating the powder layer forming step and the object building step;
• wherein the three-dimensional object is built by repeating uplifting the cover and the one-layer building step.