Optimized calculation of the unfolded length in bending of sheet metal into cold sections and pipes

Optimized calculation of the unfolded length in bending of sheet metal into cold sections and pipes

 

Motivation

Bending is one of the most common methods in the production of sheet metal parts. A significant step in the design of bending processes is to determine the initial dimensions of the sheet metal. The state of the art provides several methods to calculate the unfolded length. However, for identical sheet geometries, these different calculation methods provide divergent results regarding the necessary dimensions of the sheet metal pre-cut [Figure 1]. A possible cause of these diverging estimates may be that currently used calculation methods consider neither material properties nor specific effects of the employed bending methods. In consequence, planning manufacturing processes requires vast experience from the designer to avoid expensive correction loops in the production process.

Figure 1: State of the art: The calculation of the unfolded length leads to diverging results Objective
Figure 1: State of the art: The calculation of the unfolded length leads to diverging results Objective

Aim

Considering the material’s geometry as well as the material and process-specific paramters, the research project aims at developing a calculation method for determining the unfolded length. Furthermore, suitable modelling parameters for describing bending processes via numerical simulations are to be investigated. Moreover, the project aims at detecting an experimental method for determining the position of the unlengthened fibre.

Methodical approach

First, an experimental method for determining the position of the unlengthened fibre has to be found and tools for experimental investigations have to be designed and manufactured. Subsequently, the influence of the geometry, material properties and bending method on the position of the unlengthened fibre can be investigated in experimental studies [Figure 2]. The results of these investigations are used to design numerical simulations of the bending process to determine suitable modelling parameters. Finally, a calculation model describing the experimental results will be derived.

Figure 2: Approach for analysing the influencing factors on the unfolded length
Figure 2: Approach for analysing the influencing factors on the unfolded length

Acknowledgment

The IGF-Research Project 17702 N, supported by the Research Association for Steel Application (FOSTA), was funded in the scope of the “Progamm zur Förderung der Industiellen Gemeinschaftsforschung” (IGF) via the German Federation of Industrial Research Associations (AiF) by the German Ministry for Economy and Energy as decided by the German parliament.

Furthermore, we thank all involved companies for the support of the research project “Optimized calculation of the unfolded length in bending of sheet metal into cold sections and pipes”:

  • data M Sheet Metal Solutions GmbH, Valley
  • Dreistern GmbH & Co. KG, Schopfheim
  • European Cold Rolled Section Association, Düsseldorf
  • Gebhardt-Stahl GmbH, Werl
  • Indukant GmbH, Lennestadt
  • Profilmetall GmbH, Hirrlingen
  • RAS Reinhardt Maschinenbau GmbH, Sindelfingen
  • SSAB EMEA AB, Borlänge (Schweden)
  • ThyssenKrupp Steel Europe AG, Duisburg
  • UBECO GmbH, Iserlohn
  • Verband der Deutschen Federindustrie, Hagen
  • Wilhelm Bertrams GmbH & Co. KG, Leichlingen