Matching Materials to Roll Formers
Equipment manufacturer specifications identify what
|Black feed-in guides at the top and bottom of the entry end of
Berridge Manufacturing's portable roll former keep red coil aligned
so it feeds into the forming rollers properly.
Getting the right material matched to the right rollformer is an
essential part of making sure a project runs smoothly and doesn't
experience performance problems after installation. Mismatches can
cause problems with the equipment, material coatings, malformed
components and installation. When fabricators consider materials
for their roll formers, it's critical to follow the equipment
manufacturers' specifications. And it may be necessary to directly
contact these companies if a new material is being considered. Roll
formers vary in functionality in numerous ways including what types
of materials they can form. Some are fixed for a single profile and
material. Others are adjustable and can handle a range of materials
and profiles. The characteristics of the materials that are
considered when matching metal to machine include the type of
metal, thickness, finish, yield strength and width, all of which
are specified by roll former manufacturers.
Joseph Tripod Jr. is director of the product solutions group at
N.J.-based Englert Inc., which manufactures and supplies roll
forming materials and equipment. "It is paramount that
[fabricators] follow the manufacturer of the equipment's
instructions," Tripod says. "This isn't really a choice of what you
think is good, or what material you think is good for your machine,
it's a matter of what the machine was designed to handle."
Various types of steel, aluminum, copper and zinc may be used to
produce roof panels, wall panels and gutters with roll formers, but
not all machines run all of them. As new materials continue to be
developed and are brought to market, equipment manufacturers
determine if their roll formers have the ability to run them.
Tripod says there's been a noticeable increase in the demand for
7-mm and 8-mm zinc from his company. And, this year, one of
Englert's customers inquired about roll forming 24-gauge Corten
steel on a job site with one of the company's machines. "It is
something different; we had not seen or heard anybody put Corten
through [a roll former]," Tripod says. "We were a little concerned
about what it would do to the die set, but so far, so good."
Red coil feeds vertically into Berridge Manufacturing's on-edge
Some roll formers use one material thickness; others can run
material at two or more thicknesses. Kurt Schievelbein, technical
manager of roll forming at San Antonio-based Berridge Manufacturing Co.,
which also manufactures and supplies roll forming materials and
equipment, says his company's equipment primarily uses 24-gauge
material, some 22-gauge and aluminum.
"If you run material that's too thick, you could overload the
drive unit and bog it down; it'll just stop," Schievelbein says.
The drive system can be damaged. "If it's a chain-driven unit, it
could break chains; if it uses gears, it could damage the gears,"
he says. "Sometimes you'll literally have to cut whatever kind of
material you're running out of there."
If the material running through a roll former is thinner than
what the machine is designed for, the metal will be formed
improperly. "The bends will be too open," Schievelbein says. "If
you need a vertical leg at 90 degrees, you may get something out of
it at 70 degrees." Malformed components cause installation
problems. "The panel systems wouldn't fit together properly," he
says. "And also aesthetics, it wouldn't look good."
Finishes and Coatings
Manufacturers of roll formers determine which finishes and
coatings on materials are compatible with their products. Tripod
says most of Englert's roll formers for gutters and panels run
materials with standard two-coat and three-coat Kynar finishes.
There are heavier coats including silicone modified polyesters
(SMPs), four-coat systems and coatings with thick-film primers. "We
shy away from those because the paint gets thick, and if the
forming gets too tight, the shape gets too tight and you can crack
the finishes in some places," Tripod says. Such cracking would
compromise the warranty on a material. "So there is a limitation to
the thickness of a coating, and roll formers are designed to do
certain things," he says.
Watching for Yield Strength
A metal panel exits Berridge Manufacturing's roll former.
Most of Berridge Manufacturing's roll formers run material with
a yield strength between 40 KSI and 55 KSI, Schievelbein says. If a
material with higher yield strength than a roll former was designed
for is used, the bends will be formed incorrectly. "You'll have a
lot of spring-back in the panel," Schievelbein says. "They would be
opened up rather than closed down to the specs you wanted to hold
those things at. If you had a panel pan that was flat with a yield
strength that was too high, and you wanted a leg going up at 90
degrees, then that would cause the leg to flare out, to be open,
maybe 80 degrees or 65 degrees, but it would not be where you
The width of the material running through a roll former is
crucial to forming components well. In most cases, metal coil is
used, and the width is determined when it's ordered. However, if a
fabricator is producing a small number of components by cutting
strips from flat sheets of metal on a plate shear, material width
can be less reliable.
"[Fabricators] maybe won't get it to the correct width, not have
it square on the shear or maybe the shear is out of adjustment, and
it cuts it at a very slight taper," Schievelbein says. "So it's
going to be narrow on one end and wide on the other. It either jams
in the machine or it may taper from one end to the other one, so
when they try to lock it together, it may lock on one end and not
the other, and halfway lock in the middle."