The invention relates to a granule/liquid flow adjusting device for 3-D printer heads supplied with granules and/or liquids, said device being arranged in a 3-D printer head which is fed via a channel. The printer head comprises a chamber, and the chamber has a surface, said surface having at least one outlet bore. According to the invention, at least one conveyor is arranged within the chamber, said conveyor supplying the material, preferably plastic, to the at least one outlet bore. The conveyor is urged in the direction of the surface by force, and the distance between the conveyor and the surface is adjusted by the pressure of the material.