A fin block is provided for a calibrating device for the calibrating of an extruded plastic profile, wherein the fin block includes a back structure and a fin structure having a plurality of fins. The fins are spaced apart from one another and arranged on the back structure in longitudinal direction (L) of the back structure. The back structure of the fin block has a plurality of apertures, the shape and/or arrangement of which within the back structure depends on a predetermined mechanical load capacity for the back structure. Furthermore, a method for the production of the above-mentioned fin block and a calibrating device, which includes a plurality of the above-mentioned fin blocks, is provided. Furthermore, a system for the additive manufacture of the above-mentioned fin block, a corresponding computer program and a corresponding data set is provided.