US Patent 11167494 3D printing method and apparatus

A printing apparatus is for printing a three-dimensional object having an operative surface; a plurality of supply hoppers for dispensing powder, the powder being adapted to be melted by an energy beam, wherein the supply hoppers are configured to form a plurality of vertically-aligned powder beds adjacent to one another on the operative surface simultaneously; and an energy source for emitting an energy beam onto each powder bed simultaneously to melt or fuse a topmost layer of the powder bed onto an underlying powder bed layer or substrate.