A stacker component of an apparatus for automated manufacturing of three-dimensional composite-based objects for aligning registration of sheets. The stacker includes a sheet catcher; a frame having a base plate with the base plate having tapered registration pins to align a stack of substrate sheets. The registration pins are mounted in the base plate and project vertically to a location just below the sheet catcher. The stacker also has a presser with a press plate and a belt driver system that moves the press plate up and down allowing the press plate to exert downward pressure on the stack and a slide system with two guide rails that enable the base plate to be loaded and unloaded. A conveyor can be disposed so that after a substrate sheet exits a powder or printing system, the sheet is conveyed onto the sheet catcher.