Preform for internal high-pressure forming (IHPF) by flexible roll forming


In this research project the focus lies on closed profiles with a variable cross-section. Such closed profiles are usually produced in sheet metal manufacturing industry only under high effort in multistage processes, such as assembling several sheet metal elements. The flexible roll forming process offers a new approach to manufacture semi-finished products. By using the inner high-pressure forming (IHPF) on tubes with a constant cross-section, only limited part geometries with over the length varying cross-sections are producible. Major expansions are only realizable by additional operations such as annealing. In contrast, the utilization of semi-finished products with varying cross-sections open up new opportunities for hydroforming to produce components with large differences in cross-sections under economic conditions.


The aim of this research project is the extension of achievable geometry spectra in terms of cross-sectional differences for sheet metal parts by IHP forming. One goal is to implement a process chain consisting of flexible roll forming, conventional roll forming and IHP forming. For closing the profiles the influences of the previous processes need to be understood and controlled. By carrying out component tests the properties of the profiles are determined and guidelines for the design of flexible roll formed parts can be established.


By analytical and numerical approaches the preform of the flexible roll formed parts are determined. Experimental studies on roll forming and closing the profiles by welding are conducted. Forming processes like bending and IHPF will be conducted. After component tests for characterizing the semi-product profile a prototype part will be formed by hydroforming. On basis of the results design guidelines will be developed for products with the described properties.

Project Partners

Daimler AG
data M Software GmbH
Simufact Engineering Gmbh
Hydro-Aluminium Deutschland GmbH
Lang Rohr-Biegemaschinen GmbH+Co. KG
Siebenwurst Werkzeugbau GmbH