Patent attributes
An additive manufacturing method is provided for building a manufacturing object by building of repeating formation of one of a sintered portion or a fused portion by selectively heating a thinly developed powder material within a working region on the basis of drawing data derived from three-dimensional data of the manufacturing object and further formation of a new thin layer on one of the sintered portion or the fused portion. The additive manufacturing apparatus includes one or more channels connecting the inside and the outside of the region, and introduces a fluid into a crack progressing into the un-fused powder material through the channel after completion of building to forcibly cool one of the sintered portion or the fused portion, and the un-fused powder material.