Bending of sheet metal of complicated shapes (for 90 o angle and more) in combined tools

Purpose: Paper describes bending of sheet metal for angles greater than 90 degrees on simple forming tools. Bending using the bending method „traktrix” (in two steps) or the method „turning of the strip” (in one step) can be used for more complicated bends, i. e., for 90 degrees or more. Design/methodology/approach: We used the principle of “traktrix“ curve known in field of deep drawing process in bending process. The bending method, based on „traktrix” curve for more complicated bends, i. e., for 90o or more was developed. A sketch of 90o bending of unknown author and unknown source existed. Findings: It’s possible to bend sheet metal for 90 degrees or more using “traktrix” curve. Research limitations/implications: The research was limited by time and costs. We carried out the research till we get the described product. Future research should be performed in field of parameters of bending tool. Practical implications: We made only one version of each method, of course for practical reasons since we did not need different angles on one product. It would be appropriate to complement both methods in detail theoretically and by testing in the frame of a more comprehensive research work. Originality/value: This article describes the original approach to bending of sheet metal for angles greater than 90 degrees. Movement of forming tool is carried out only in vertical direction and therefore savings by construction and manufacturing of bending tools are possible.