Techniques for rapid powder removal in a 3-D printer are disclosed, In various embodiments, the 3-D printer has a build plate for supporting a build piece. The build plate includes first structures for supporting unfused powder on a top of the build plate when the first structures are in a closed configuration. The first structures can transition to an open configuration to expose paths for allowing the unfused powder to pass through the build plate, and a second structure for preventing the build piece from passing through the build plate when the first structures are in the open configuration. In various embodiments, the unfused powder can thereafter be replaced with cool powder to assist in forming a predictable microstructure that makes up the build piece.