A new 3D printing process for printing EVA foam is to be developed. The process is to be used for the production of customizable orthopaedic soles. The development of a 3D printer as a stand-alone device for orthopaedic shoemakers is planned. A special feature of the process is that EVA granulate is to be fed directly to the printer instead of plastic filament, as is usually the case with 3D printing processes. For this purpose, a chemical blowing agent is to be incorporated into the EVA granulate in an upstream compounding module, which is then activated during the printing process. Until now, orthopaedic soles have been milled from sheets, which means a high proportion of waste. This can be significantly minimized with this new 3D printing process. Another innovative feature is the locally resolvable variation in foam hardness during the printing process. This is to be technically implemented with specially arranged (UV) LEDs, which influence the foaming behavior and thus the foam properties through a variable energy input into the melt, whereby the foam hardness can be varied locally.