Spring back will occur and must be
compensated for when a radius exceeds four times the thickness of
material being formed. As the radius increases more over bend must
be made to get the proper formed radius. Radius die sets are typical
fitted for one gauge and type of material.
R-2 Radius Die Set
The R-2 contains a spring-pad in the die that
keeps kinking to a minimum and offers better results when lighter
gauge materials are used.
R-3 Radius Die Set
The R-3 die set is used when forming
a radius close to a flange. The preformed flange will have to be
formed to less than 90° .
R-4 Radius Die Set
The R-4 die set forms an outside flange and
radius in one operation.
R-5 Radius Die Set
The R-5 die set is used for forming a radius
starting lip when a rolling process is required. This operation
leaves a flat at the edge of the sheet. The R-5 die set can also be
used to bump different radii in a range of material. By adjusting to
distance between bends lager radii can be bump formed.
R-6 Radius Die Set
The R-6 is used when forming a radius with an
inturned flange to the end of the radius. The lower die has a wiper
plate at each end to hold the flange square and limit the wrinkling
of the flange.