Tool Design

By the nature of the process, many stresses are created during roll forming. These must be minimised and equalised as much as possible during manufacturing. Forming tools must be designed to form the material progressively.

Corrugated and ribbed profiles are most often formed from the centre and moved outward thereby “pushing” the differential stresses to the edges of the sheet. Generally, profiled metal rib and corrugated profiles, flashings, and most trough sections can be expected to provide finishes free of avoidable distortion.

Standing seam profiles typically need more forming on the edges of the feed material and little or none in the centre of the sheet, which tends to trap uneven stresses in the centre of the profile. Often one edge requires more forming than the other, meaning the stresses developed are not even in the sheet.

Some evenly distributed oil canning can normally be expected in standing seam products with a width of more than 300 mm, and it is considered acceptable.