A three-dimensional (3D) printing system includes a resin vessel, a fabrication subsystem, a waste collection subsystem, and a controller. The resin vessel is configured to contain photocurable resin. The fabrication subsystem is configured to form the 3D article with layer-by-layer selective curing of the photocurable resin. The fabrication subsystem includes a build plate, a build plate support structure, and a vertical movement mechanism. The waste collection subsystem is attached to the build plate support structure and configured to capture partially polymerized resin as the build plate support structure moves in an upward direction. The controller is configured to (a) operate the vertical movement mechanism to translate the build plate support structure to a lower position and (b) operate the vertical movement mechanism to raise the waste collection subsystem up through the resin and to a position at which partially polymerized resin can be unloaded from the waste collection subsystem.