Now available dualbox: Two containers with movable bottom
During printing the bottom of the feeder box goes up. The bottom in the model box goes down. A spinning roller is used to wipe a thin layer of powder from the feeder box to the model box.
The construction of the boxes is very compact:
The bottom pulls itself up with threads that are wound around the axis of a geared stepper motor. This is very compact. You can easily take out the model box.