Revisiting formability and failure of polymeric sheets deformed by Single Point Incremental Forming

Single Point Incremental Forming (SPIF) has been intensively investigated in the last two decades. It is a versatile and economical manufacturing technology that is especially viable for small and medium-sized batches, with a great potential for manufacturing highly customized parts. One of the most important advantages of this technology is the greater formability it can attain compared to conventional sheet forming processes. The aim of this paper is to evaluate the overall formability of a series of polymeric sheets deformed by SPIF process, including biocompatible and non-biocompatible materials, while considering a variety of process parameters including spindle speed which, in previous studies on polymers formed by Incremental Sheet Forming (ISF), has been shown to be the most influential process parameter. The results show that variations in spindle speed caused a variation in the forming temperature and the material forming limits. For a better understanding of the deformation mechanism and the failure process of polymers during SPIF, a fractographic analysis using optical microscopy was carried out, as well as a Differential Scanning Calorimetry (DSC) analysis to determine the glass transition and melting temperatures and the degree of crystallinity of the polymers.