Sheet Hemming with Rolling Tools: Analysis and Optimization of the Part Quality


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The present paper is the continuation of a research conducted on hemming operations by using rolling tools. Sheet hemming is a joining operation widely used in automotive industry when it is necessary to join two sheet parts (such as the engine hood or the door panels with their internal frame) by plastic deformation of the edge of the outer part. The whole process is characterised by a 90° sheet flanging, a pre-hemming (up to approximately 135°) and the final hemming where the outer sheet edge is bended up to 180° clamping the inner sheet. Hemming processes are normally performed using rigid dies in series production and manually in pre-series and small batch production, due to the high cost of the dies. Nowadays, rollers moved by robots are becoming an interesting alternative to the manual operations especially when flexible productions are required. Even if the process time is higher, this solution can help in minimizing set-up times and costs. The required equipments are a support and a blocking system for the sheets together with the rollers mounted on a CNC machine or on a robot. The production flexibility is guaranteed by changing the 3D tool path using a CAD/CAM system. Authors are dealing with this technique having conducted many experiments studying the influence of the hemming process parameters such as flange geometry (edge height, fillet radius), distance of the inner panel from the flange, tool path sequence, along straight paths on steel sheets. The goal of the present research is to study the material behaviour and the produced parts quality when working on aluminium sheets. In particular, both experimental tests and simulations will be carried out in order to optimize the process.



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Edited by:

F. Micari, M. Geiger, J. Duflou, B. Shirvani, R. Clarke, R. Di Lorenzo and L. Fratini




E. Ceretti et al., "Sheet Hemming with Rolling Tools: Analysis and Optimization of the Part Quality", Key Engineering Materials, Vol. 344, pp. 357-364, 2007

Online since:

July 2007




[1] A. Muderrisoglu, H. Livatyali, M. Ahmetoglu and T. Altan: Computer Aided Design for Bending, Flanging and Hemming of Steels and Aluminum Alloys, Proceedings of the PMA METEALFORM '97 Symposium (1997) Chicago, IL, USA, pp.151-158.

[2] S. Larris and T. Altan: Investigation of key characteristics of flanging and hemming of flat surface-curved edge sheet metal (Report No. S/ERC/NSM-99-R-30, USA 1999).

[3] H.C. Wu, W. Thomas, H. Livatyali and T. Altan: Analitical and numerical investigations of sheet metal bending, flanging and hemming (Report No. S/ERC/NSM-99-R-37, USA 1999).

[4] H. Livatyali and T. Altan: Experimental investigation on forming defects in flat surface-convex edge hemming: roll, recoil and wrap, Journal of Materials Technology Vol. 153-154 (2004), pp.913-919.


[5] M. Svensson and K. Mattiasson: Three-dimensional simulation of hemming with the explicit FEMethod, Journal of Materials Processing Technology Vol. 128 (2002), pp.142-154.