Mitigation of Geometric Inaccuracy in Closed-Contour Incremental Sheet Forming via Curvilinear Toolpath

Abstract:

Geometric deviations remain a major barrier to the widespread industrial adoption of incremental sheet forming (ISF). Compared with conventional toolpath compensation that rely on extensive data generation and trial-and-error procedures, variation of toolpath styles offers a more direct and efficient strategy for mitigating geometric defects. In this study, multiple curvilinear toolpath strategies were investigated for a standard closed-contour ISF part to evaluate their effectiveness in reducing geometric deviations. Six toolpaths were examined, including three established types – convex, concave, and wavy – and three novel toolpaths proposed in this work: adaptive, cusp, and sine. The convex toolpath achieved the largest side-wall springback reduction relative to the linear baseline but introduced a significant bottom pillow effect and reduced formability. While the cusp toolpath effectively suppressed both springback and pillow formation, it resulted in local thickening and degraded surface finish. Overall, the sine toolpath provided the most balanced performance, achieving effective reduction of all major geometric defects. Numerical simulations reveal an inherent tradeoff between side-wall springback reduction and bottom pillow formation, as positive residual bending moments formed in the pillow region contribute to springback mitigation by promoting outward bending of the side walls.

• Periodical: Solid State Phenomena (Volume 389)
• Pages: 181-189
• DOI: https://doi.org/10.4028/p-f59c2L
• Online since: April 2026
• Authors: Zixuan Mu*, Youngrok Lee, Jeffrey Abell, Alan Taub, Mihaela Banu
• Keywords: Bending Moments, Bulge, Curvilinear, Incremental Sheet Forming, Pillow Effect, Springback, Toolpath Strategies

References

[1] Lu, H., Liu, H. and Wang, C., 2019. Review on strategies for geometric accuracy improvement in incremental sheet forming. The International Journal of Advanced Manufacturing Technology, 102(9), pp.3381-3417.

DOI: 10.1007/s00170-019-03348-3

[2] Vanhulst, M. et al., 2025. ESAFORM benchmark 2024: study on the geometric accuracy of a complex shape with single point incremental forming. International Journal of Material Forming, 18(3), p.72.

[3] Lee, Y., Mu, Z., Bansal, A., Taub, A. and Banu, M., Enhancing accuracy in two-point incremental sheet forming (TPIF): The influence of compliance and effective squeeze factor. Materials Research Proceedings, 54.

DOI: 10.21741/9781644903599-145

[4] Bharti, S., Paul, E., Uthaman, A., Krishnaswamy, H., Klimchik, A. and Abraham Boby, R., 2024. Systematic analysis of geometric inaccuracy and its contributing factors in roboforming. Scientific Reports, 14(1), p.20291.

DOI: 10.1038/s41598-024-70746-3

[5] Behera, A.K., Verbert, J., Lauwers, B. and Duflou, J.R., 2013. Tool path compensation strategies for single point incremental sheet forming using multivariate adaptive regression splines. Computer-Aided Design, 45(3), pp.575-590.

DOI: 10.1016/j.cad.2012.10.045

[6] Ren, H., Xie, J., Liao, S., Leem, D., Ehmann, K. and Cao, J., 2019. In-situ springback compensation in incremental sheet forming. CIRP Annals, 68(1), pp.317-320.

DOI: 10.1016/j.cirp.2019.04.042

[7] Bingqian, Y., Zeng, Y., Yang, H., Oscoz, M.P., Ortiz, M., Coenen, F. and Nguyen, A., 2024. Springback prediction using point series and deep learning. The International Journal of Advanced Manufacturing Technology, 132(9), pp.4723-4735.

DOI: 10.1007/s00170-024-13632-6

[8] Lu, B., Chen, J., Ou, H. and Cao, J., 2013. Feature-based tool path generation approach for incremental sheet forming process. Journal of Materials Processing Technology, 213(7), pp.1221-1233.

DOI: 10.1016/j.jmatprotec.2013.01.023

[9] Cappellini, C., D'Urso, G. and Giardini, C., 2025. Multi-Step Tool Paths Development for Reducing Geometric Deviation and Pillow Effect in the Single-Point Incremental Forming. Journal of Manufacturing Science and Engineering, 147(7), p.071005.

DOI: 10.1115/1.4068238

[10] Vanhulst, M., Vanhove, H., Duflou, J.R., Araujo, A.C., Cantarel, A., Chabert, F., Korycki, A., Olivier, P. and Schmidt, F., 2024. Influence of toolpath strategies on the final accuracy and thickness distributions in multi-stage incremental forming. MATERIAL FORMING, ESAFORM 2024, 41, pp.1498-1506.

DOI: 10.21741/9781644903131-166

[11] Said, L.B., Mars, J., Wali, M. and Dammak, F., 2016. Effects of the tool path strategies on incremental sheet metal forming process. Mechanics & Industry, 17(4), p.411.

DOI: 10.1051/meca/2015094

[12] Grimm, T.J. and Mears, L., 2020. Investigation of a radial toolpath in single point incremental forming. Procedia Manufacturing, 48, pp.215-222.

DOI: 10.1016/j.promfg.2020.05.040

[13] Chang, Z., Huang, W. and Chen, J., 2020. A new tool path with point contact and its effect on incremental sheet forming process. The International Journal of Advanced Manufacturing Technology, 110(5), pp.1515-1525.

DOI: 10.1007/s00170-020-05960-0

[14] Grimm, T.J., Ragai, I. and Roth, J.T., 2018. Utilization of wavy toolpath in single-point incremental forming. In ASME International Mechanical Engineering Congress and Exposition (Vol. 52019, p. V002T02A029). American Society of Mechanical Engineers.

DOI: 10.1115/imece2018-86885

[15] Bremen, T. and Bailly, D.B., 2024. On the Influence of Wave-Shaped Tool Path Strategies on Geometric Accuracy in Incremental Sheet Forming. Journal of Manufacturing and Materials Processing, 8(1), p.27.

DOI: 10.3390/jmmp8010027

[16] Shin, J., 2021. Investigation of Incremental Sheet Forming (ISF) using Advanced Numerical and Analytical Approaches. PhD thesis, University of Michigan.

[17] Burchitz, I.A., 2008. Improvement of springback prediction in sheet metal forming. PhD thesis, University of Twente.