Forming force and temperature effects on single point incremental forming of polyvinylchloride

Incremental Sheet Forming (ISF) is a technology that allows producing highly customized products at a reasonable manufacturing cost, and Single point incremental forming (SPIF) is one of the simplest ISF processes. In this sense, recent research works have revealed an increasing interest in forming thermoplastic materials by ISF. The present paper focuses on determining the influence of the main process parameters, i.e. the step down, spindle speed, feed rate, tool diameter and sheet thickness, on the maximum forming force. Maximum depth has been analyzed as a formability indicator and surface roughness has been also addressed. The results show a significant effect of the spindle speed in the ISF process of polymeric materials, not only on the maximum forming force but also on its formability, by means of the maximum depth reached, and on the surface roughness achieved. This is a consequent of the triggered increment of temperature obtained due to the friction between the tool and the sheet blank, as far as temperature variation is supposed to be the main factor causing the variation of the mechanical properties of thermoplastic polymers. The material used in this research work was polyvinylchloride (PVC), which becomes rubber-like with the increase of temperature as a consequence of its viscoelastic behaviour.