CAD-models were designed using Inventor (Autodesk, Inc.) and Simplify3D as slicing software. For 3Dprinting a modified X400 PRO V3 (German Reprap GmbH) printer was used. The original extruders were replaced by a Titan-model (E3D-Online Ltd.) and a fan for ventilation of the printing model was installed. The printing bed was prepared with an adhesive agent (Wolfbite Ultra, AIRWOLF 3D PRINTERS) to increase adhesion of PP-prints.