On the effective peek application for customized cranio-maxillofacial prostheses: An experimental formability analysis

Abstract

Single Point Incremental Forming (SPIF) is a dieless and flexible forming technology that allows performing complex shapes and presents a high economic payoff for low production series. In this context, this research presents an experimental investigation of Polyether ether ketone (PEEK) sheets deformed by SPIF at room temperature, determining the influence of the process parameters on the material formability. The research is performed in terms of principal strains that are evaluated within the material Forming Limit Diagram (FLD) obtained by means of Nakajima tests allowing to establish the forming limits of PEEK sheet material. On the other hand, the results of the SPIF tests performed gave rise to an analysis in terms of formability, modes of failure, temperature, forming force, and geometry accuracy. These experiments allow assessing the optimal parameters and forming methodologies/procedures for the manufacturing of cranio-maxillofacial prostheses. In this sense, it was performed a global study in terms of the formability of the manufactured prostheses, as well as the shape accuracy, temperature and roughness analysis, among others. This research showed that the maximum strains attainable by the two prostheses were still found far away from the Fracture Forming Limit (FFL) of the material, showing the feasibility to obtain extra formability within the forming safe zone. In conclusion, this work proved the high potential of manufacturing prostheses in the biomedical field using Incremental Sheet Forming (ISF) processes in combination with advanced biocompatible polymers such as PEEK.