Enhancing accuracy in two-point incremental sheet forming (TPIF): The influence of compliance and effective squeeze factor
Youngrok Lee, Zixuan Mu, Ankush Bansal, Alan Taub, Mihaela Banu
Abstract. Two-point incremental forming (TPIF) enhances geometric accuracy by incorporating a backing die; however, machine and tool compliance often introduce discrepancies between the programmed squeeze factor (〖SF〗_p) and the effective squeeze factor (〖SF〗_e), leading to “degenerated TPIF”, where the sheet-die contact is lost throughout the process. This study investigates compliance-induced deflections and introduces an empirical relation to predict 〖SF〗_e based on measured compliance and baseline radial force, enabling a predictive toolpath generation approach that minimizes trial-and-error adjustments. Experimental validation was conducted using AA7075-O across different tool designs and truncated cone geometries with wall angles of 45° and 67°. Geometric profile, surface texture, and forming force evolution were analyzed to assess the effect of system compliance on material squeeze and forming accuracy. Results demonstrate that a tapered tool with lower system compliance maintained sheet-die contact at 〖SF〗_p = 10% for the 45° cones, whereas a conventional tool design required 〖SF〗_p ≥ 40%. These findings confirm that minimizing system compliance through tool design improves material squeeze and geometric accuracy. Furthermore, a finite element model of the 67° incorporating 〖SF〗_e accurately predicted forming forces and deformation trends, closely matching experimental observations. These findings establish a practical framework for improving geometric accuracy and optimizing TPIF toolpath generation, offering significant advantages for industrial applications.
Keywords
Two-Point Incremental Forming (TPIF), Compliance, Squeeze Factor, FEA
Published online 5/7/2025, 10 pages
Copyright © 2025 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: Youngrok Lee, Zixuan Mu, Ankush Bansal, Alan Taub, Mihaela Banu, Enhancing accuracy in two-point incremental sheet forming (TPIF): The influence of compliance and effective squeeze factor, Materials Research Proceedings, Vol. 54, pp 1333-1342, 2025
DOI: https://doi.org/10.21741/9781644903599-145
The article was published as article 145 of the book Material Forming
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
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