Five Ways to Determine the Initial Sheet Width in Bending

Abstract

Different bending methods are applied in manufacturing sheet metal parts. Research on sheet metal bending has identified several distinct ways of determining the initial sheet width (e.g., by Oehler,1 by Mäkelt,2 and by DIN 69353), also termed unfolded length, but has been unable to resolve the question which of these methods is most advisable in general. Especially in roll-forming, where multiple bend operations occur within the same bend part, these different calculation methods lead to differing recommendations for the initial sheet width. One approach to resolving this discrepancy is the experimental investigation of the position of the unlengthened fiber in bending. This study compared five different experimental approaches to determining the position of the unlengthened fiber in order to identify the most advisable approach – a prerequisite for improving the calculation of the unfolded length.