Numerical and experimental exploration of patient-specific cranial implants with 3D-printed PEKK via Arburg Plastic Freeforming

Abstract This study explores the use of Arburg Plastic Freeforming (APF) technology to produce patient-specific implants (PSIs) using the high-performance polymer polyether–ketone–ketone (PEKK). The APF process allows printing PEKK in an amorphous state, improving toughness and reducing distortion compared to PEEK, with minimal stiffness loss. Three-point bending (TPB) specimens were printed in two orientations and tested to characterise the material. The TPB tests showed minor reductions in mechanical properties, and DSC analysis confirmed the amorphous nature of the printed PEKK. A cranial PSI was also fabricated and subjected to static compression testing. The cranial plate exhibited strong layer adhesion, showing acceptable displacement under loads comparable to those from severe impacts. Finite element analysis (FEA) of the cranial plate was conducted using material properties from technical datasheets and TPB results. FEA results closely matched experimental findings, validating the use of TPB-derived properties for accurate simulation. The findings indicate that APF-printed PEKK is suitable for craniofacial PSIs, offering improved mechanical compatibility and fabrication precision. Further research is needed to evaluate the dynamic impact behaviour and long-term biocompatibility to fully establish clinical applicability.