The invention relates to a 3D printer (100) which is designed to produce, in layers, a three-dimensional component by forming superimposed layers of a particulate material and by selectivity hardening a partial region of the respective component layer. The 3D printer (100) is designed to produce one or more first three dimensional components in a first chamber (B1) arranged in the 3D printer, and simultaneously, one or more second three-dimensional components in a second chamber (B2) which is adjacent to the first chamber and which is at a horizontal distance thereto and which is arranged in the 3D printer.