Each profile cross section needs a customized set of roll tools. First, after defining the final profile cross-section, the flower pattern has to be designed. This means, starting with the final section, the cross section of the profile in each stand is defined by unbending the arcs. Afterwards, the rolls have to be designed by deriving the roll contour from the profile contour in each stand.
A special roll forming problem is the longitudinal strain within the sheet. To avoid remaining strain and unwanted deformations, it is necessary to check just in time, if the longitudinal stress does not meet or exceed the yield stress. During flower pattern creation, the stress can be checked approximately by the Stress of Band Edge Calculation or by the Profile Stress Calculation (PSA).
After completion of the roll design, the FEA method can be used for a final check. It also helps to evaluate if the designed roll tools are able to form the desired profile with the given allowances.
The last step is to export the manufacturing data like parts list (sawing list) and the program for the CNC lathe.