skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Numerical Simulations and Experimental Researches for Determining the Forces of Incremental Sheet Forming Process

Abstract

The current paper refers to one of the new non-conventional forming procedures for sheets metal, namely incremental forming. Problems occurring during calculation of stress, thinning and the forces in the process of incremental sheet metal forming have been analyzed in this paper. The paper presents a comparison study based on the simulation by the finite element method of incremental sheet metal forming and experimental researches referred on the same process.

Authors:
; ; ;  [1]
  1. University 'Lucian Blaga' of Sibiu, Engineering Faculty, Department of Machines and Equipment, Emil Cioran, 4, 550025, Sibiu (Romania)
Publication Date:
OSTI Identifier:
21057019
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 907; Journal Issue: 1; Conference: 10. ESAFORM conference on material forming, Zaragoza (Spain), 18-20 Apr 2007; Other Information: DOI: 10.1063/1.2729519; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; FINITE ELEMENT METHOD; MATERIALS WORKING; METALS; SHEETS; STEELS; STRESSES

Citation Formats

Oleksik, Valentin, Bologa, Octavian, Racz, Gabriel, and Breaz, Radu. Numerical Simulations and Experimental Researches for Determining the Forces of Incremental Sheet Forming Process. United States: N. p., 2007. Web. doi:10.1063/1.2729519.
Oleksik, Valentin, Bologa, Octavian, Racz, Gabriel, & Breaz, Radu. Numerical Simulations and Experimental Researches for Determining the Forces of Incremental Sheet Forming Process. United States. doi:10.1063/1.2729519.
Oleksik, Valentin, Bologa, Octavian, Racz, Gabriel, and Breaz, Radu. Sat . "Numerical Simulations and Experimental Researches for Determining the Forces of Incremental Sheet Forming Process". United States. doi:10.1063/1.2729519.
@article{osti_21057019,
title = {Numerical Simulations and Experimental Researches for Determining the Forces of Incremental Sheet Forming Process},
author = {Oleksik, Valentin and Bologa, Octavian and Racz, Gabriel and Breaz, Radu},
abstractNote = {The current paper refers to one of the new non-conventional forming procedures for sheets metal, namely incremental forming. Problems occurring during calculation of stress, thinning and the forces in the process of incremental sheet metal forming have been analyzed in this paper. The paper presents a comparison study based on the simulation by the finite element method of incremental sheet metal forming and experimental researches referred on the same process.},
doi = {10.1063/1.2729519},
journal = {AIP Conference Proceedings},
number = 1,
volume = 907,
place = {United States},
year = {Sat Apr 07 00:00:00 EDT 2007},
month = {Sat Apr 07 00:00:00 EDT 2007}
}
  • As recent studies introduced Incremental Sheet Forming (ISF) process as a very promising technology to manufacture sheet metal parts by the CNC controlled movement of a simple generative tool, industrial interests on ISF have increased. Indeed, due to its various advantages, such process has been demonstrated as an alternative to reduce costs resulting from stamping technology when small batches or prototypes have to be manufactured. Nevertheless, the process still needs further developments. A process analysis based on experimental and numerical investigations is required to carefully analyze the capabilities of the process and to consolidate its application in sheet metal industries.more » Starting from experimental results on standard components to show the interest of ISF, an application is carried out accounting flexibility of the process linked to the fact that the punches or dies are avoided and preliminary results have been obtained through experimental tests to manufacture micro parts. At the same time, a FEM analysis has been carried out in order to get the characteristics of the formed parts. In order to study the control of the process, a first study is carried out to perform an on-line sheet thickness measurement.« less
  • Incremental sheet metal forming, which uses a CNC forming stylus, is new flexible forming process not requiring the use of any expensive dies. We have applied the incremental forming process to dental prosthesis. This new process, however, posed difficult problems. After removing the outer portion of the incremental formed sheet metal part, the inner part is distorted. In this paper, the residual stress in the sheet metal part obtained by incremental forward stretch forming operations has been examined. Numerical simulations were conducted for solid elements. When small rigid ball slides on the metal sheet with a certain vertical feed, tensionmore » residual stress is produced in the upper layer of the sheet and compression stress in the lower. Then, the resultant moments throughout the sheet cause negative spring-back when the outer portion is removed. A systematic study of the behavior was conducted in this paper. Parameters considered included the tool radius and the vertical tool feed rate. The tip radius of forming stylus has a significant influence on the residual stress. The smaller radius of forming stylus, the larger bending force becomes. And new process with double forming styluses is examined to reduce the bending force.« less
  • Incremental Sheet Forming (ISF) is a relatively new process in which a sheet clamped along the borders is progressively deformed through a hemispherical tool. The tool motion is CNC controlled and the path is designed using a CAD-CAM approach, with the aim to reproduce the final shape contour such as in the surface milling. The absence of a dedicated setup and the related high flexibility is the main point of strength and the reason why several researchers focused their attentions on the ISF process.On the other hand the process slowness is the most relevant drawback which reduces a wider industrialmore » application. In the paper, a first attempt to overcome this process limitation is presented taking into account a relevant speed increasing respect to the values currently used.« less
  • A characteristic of incremental sheet metal forming is that much higher deformations can be achieved than conventional forming limits. In this paper it is investigated to which extent the highly non-monotonic strain paths during such a process may be responsible for this high formability. A Marciniak-Kuczynski (MK) model is used to predict the onset of necking of a sheet subjected to the strain paths obtained by finite-element simulations. The predicted forming limits are considerably higher than for monotonic loading, but still lower than the experimental ones. This discrepancy is attributed to the strain gradient over the sheet thickness, which ismore » not taken into account in the currently used MK model.« less
  • The forming limits of sheets subjected to the Single Point Incremental Forming process (SPIF) is generally several times higher than those found in the Forming Limit Curve (FLC). In this paper it is shown that the non-monotonic, serrated strain paths to which the material is subjected to during the SPIF process, play a role in the high formability, compared to the monotonic loading in the traditional FLC. The deformation history of an aluminium alloy truncated cone formed with the SPIF process is retrieved through a finite element (FE) model, and discussed. Subsequently, the strain paths at three different depths inmore » the sheet are used as input into a Marciniak-Kuczynski (MK) forming limit model. The usage of different constitutive models in this analysis shows that anisotropic hardening contributes to the delay of the onset of necking in the SPIF process. The large difference in the predicted forming limits that were obtained from the different layers indicates that an interaction between these layers should be taken into account for more accurate forming limit predictions of sheets subjected to the SPIF process.« less