Journal of Materials Processing Technology 210 (2010) 363–369 Contents lists available at ScienceDirect Journal of Materials Processing Technology journal homepage: www.elsevier.com/locate/jmatprotec Experimental investigations and numerical analysis for improving knowledge of incremental sheet forming process for sheet metal parts S. Dejardin a,∗ , S. Thibaud b , J.C. Gelin a , G. Michel a a ENSMM – National Engineering Institute in Mechanics and Microtechnologies, 26 rue de l’Epitaphe, 25000 Besanc ¸ on, France b FEMTO-ST Institute – Applied Mechanics Department, 24 rue de l’Epitaphe, 25000 Besanc ¸ on, France article info Article history: Received 2 July 2008 Received in revised form 17 September 2009 Accepted 26 September 2009 Keywords: Incremental sheet forming FE model Tool trajectory Springback Deformation mechanics abstract The paper is related to the analysis of shape distortions and springback effects arising in single point incremental sheet forming in order to study the use of a FE model based on shell elements to perform simulation of the process. A comparison between numerical and experimental results is made to assess the suitability of the model. The measurements of geometrical profile of a truncated cone and springback of cut rings show that the FE model allows to predict accurate results for a set of well defined process parameters. The deformation mechanism of ISF is taken into consideration to determine the limits of the model studied. © 2009 Elsevier B.V. All rights reserved. 1. Introduction The requirements associated with customized production and cost reduction are still growing and new technologies seem to offer a sustainable approach to answer to such requests. This is a reason for the increasing interest in flexible forming processes like incre- mental sheet forming (ISF). Indeed, the ISF concept consisting in a progressive and localized deformation of a sheet metal part is flexi- ble because no specialized tooling is required. The movements over the surface of the sheet of a simple forming tool cause to a highly localized plastic deformation. Regarding the concept of such a tech- nology, a wide range of 3D shapes can be formed with a correct definition of the forming tool path controlled by a CNC machine. In addition to this, ISF also leads to a higher material formability in comparison with conventional forming processes like stamping. These advantages bring to a growing interest in both academic and industrial research centers as it is demonstrated in literature. Auto- motive panels manufactured by Amino et al. (2002) using ISF or customized medical products produced by Ambrogio et al. (2005a) are relevant examples. A global review of works and achievements made in incremental sheet forming has been proposed by Jeswiet et al. (2005). ∗ Corresponding author. Tel.: +33 6 27 81 70 29; fax: +33 3 81 40 29 02. E-mail address: steeve.dejardin@gmail.com (S. Dejardin). Despite numerous researches in ISF during the last decade, the deformation mechanism is not fully determined. A deep under- standing of the deformation mechanism is important to allow an accurate numerical modelling of the process to predict the sheet behaviour and to make possible the process control. In this sense, recent results obtained by Jackson and Allwood (2009) clearly show that there is a relevant amount of shear in ISF. So it becomes clear now that the deformation mechanism of ISF is not “almost pure stretching” as it has been described in Filice et al. (2002) or Hirt et al. (2003) for example. Therefore, these results have raised the question of the validity of numerical model based on shell elements to simulate the process. Despite the previous considerations, the reported study is focused on the possibility to use an adapted FE model of the process based on shell elements to predict accurate results associated with a well defined set of process parameters. A short review of previous works in ISF is given in Section 2 in order to clearly define the proposed study. 2. Review Many types of incremental sheet forming processes have been investigated, including the use of a flexible support or a counter pressure, the development of multipoint incremental forming as it is described in Micari et al. (2007), but the most widely used tool is a hemispherical punch. The main configurations of ISF are single point incremental sheet (SPIF) and two-point incremental sheet forming (TPIF). In SPIF, a sheet is clamped around its edges 0924-0136/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.jmatprotec.2009.09.025