This study evaluates the feasibility and suitability of polypropylene (PP) implants produced by Fused Filament Fabrication (FFF) for the substitution of damaged cranial bone material from the polymer-engineering point of view. The establishing of imaging methods, suitable printing material preparations, best printing practice regarding PP, and a first testing approach of the mechanical implant performance are addressed. Results indicate that PP implants are accurately printable and seem to be mechanical usable for cranial bone substitution. Further investigations concerning impact behavior and medical applicability will be conducted.