This paper presents recent developments in hole-flanging of metal and polymers produced by single point incremental forming (SPIF) to gaining insight into the deformation mechanics of the process and providing guidelines to foster its application in rapid prototyping and small batch production of customised sheet products. Experimentation with stainless steel AISI 304L and polyethylene terephthalate (PET) that comprised mechanical characterisation and utilisation of circle grid analysis in conjunction with the formability limit diagram gives support to the presentation and allows understanding the fundamentals of plastic flow and failure in hole-flanging produced by single point incremental forming and their main differences to hole-flanging produced by conventional pressworking.