An Experimental–Numerical Framework for Springback Prediction and Angle Compensation in Air Bending with Additively Manufactured Polymer Tools

Abstract

Additive manufacturing of polymer tools represents a promising alternative to conventional steel tooling for low-force and low-volume sheet metal air bending. However, accurate prediction of sheet springback and the resulting deviation of the bending angle after elastic unloading remains a major challenge. This study presents an integrated experimental–numerical framework for the analysis of air bending with additively manufactured polymer tools, with emphasis on material characterization, springback prediction, and tool angle compensation. The methodology combines uniaxial tensile testing, controlled air-bending experiments, finite element modelling with rigid and deformable tools, and optical 3D scanning for angle measurement. Low-carbon steel DC04 sheets were modeled using an elastoplastic constitutive law, while FDM-printed ABS tools were described by experimentally calibrated material models. Numerical simulations were performed over a range of forming forces to evaluate springback behavior and elastic tool deformation. The results show very good agreement between experiments and simulations. Deviations in bending angle were below 1.5% for metallic tools and below 0.5% for springback compensation, with the smallest discrepancy obtained using a two-dimensional model with deformable tools. Experimental validation with ABS tools confirmed bending accuracy within ±1°. The proposed framework provides a reliable basis for springback prediction and rational design of additively manufactured polymer tools for air-bending applications