The beading technique is suitable for thin metal applications. Beading doesn't break the protective coating and doesn't reduce the thickness at the bent section.
A rotary punch performs perforating or interruptive slitting.
The False-bend Technique
Figure 2
Two examples of the false-bend technique show how the bottom section is curved to allow the top roll to make the 90-degree angle at the left side of the part.
The false-bend technique exposes the blind bend (the air bend) to the top roll or bottom roll by curving a straight section (see Figure 2). After the section is curved, the top roll can physically reach the interior bend and form it to 90 degrees precisely. The station after the false-bend station flattens the curve. Usually the false-bend design needs an additional station.
