Heat-assisted incremental sheet forming for high-strength materials - a review

Single-point incremental forming (SPIF) is a sheet forming technique that deforms sheet materials incrementally to a designated shape. The process has shown high ability to deform low-strength materials for good geometrical accuracy and formability at room temperature. Deforming high-temperature alloys, such as high-strength steels and Ti-6AI-4 V, requires integrated heat sources to increase the ductility of the metal sheets for deformation. However, the integration of heating results in unpredictable thermal behaviours and impacts the formability, geometric accuracy, thickness distribution and surface quality. Considerable research efforts have invented different heating methods and designed novel tools and analytical modelling to resolve the limitations. The current challenge remains improving the localised and stable heating, functional tool design to reduce the thermal expansion and friction at the tool-surface contact area and the analysis of relationship between thermal and mechanical effects. This study aims to review the heating-assisted SPIF systems for high-strength alloy sheets to solve the current limitations. The method includes analysis of heating systems, tool, tool path design, lubricants and macro- and micro-numerical analyses. Additionally, the study aims to correlate the microstructural properties to the mechanical behaviours and subsequent effects on forming force, strain, springback, geometrical accuracy and surface quality.