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Rolling Along: Forming Wall Siding

Angle Iron

What is roller forming?

Of all of the production processes, roller forming is the most interesting, simplest and most productive. To envision it, think of a very long strand of flat metal about a few feet wide that can stretch across the length of a large factory and beyond. This is the potential capacity of a roller forming machine, which is only limited by the length of the metal fed into it. A well-tuned roller forming machine can produce close to 70,000 parts per year, far more than any other form of production.

Roller forming is far more complicated than simple placement of a flat metal sheet and outcomes apart. Its technical design requires precise and incremental calculations to control the process and ensure a useable final product. As the roll of metal progresses through the machine, it is very slowly bent and shaped. The individual stresses transform the flat metal sheet into a variety of shapes. The rollers perform a very small portion of the bend to avoid overstressing the metal, which is the precision aspect since rapidly bending metal forms creases and cracks.

Once the bending is completed, the final part will match the profile of the desired shape, which is then cut to the required length. The metal fed into the machine determines what the final shape will be since it has to be malleable enough to conform to the specified requirements. To end up with a viable product, each step of the process has to be closely monitored and inspected.

In some ways, roller forming is similar to an assembly line where each worker has their own part to play in the final product. The difference, in this case, is that the workers are replaced by rollers designed to do the simplest of functions. It can be compared to a chef preparing a gourmet meal where each step of the preparation, no matter how small, has to be done in accordance with exact timing or the meal is ruined.

Types of metals that can be roller formed

Any type of metal can be used in roller forming whether it is hot or cold. The most common types are carbon steel, stainless steel, aluminum, copper and brass. The only restriction is that the metal must be able to be bent and shaped. The types of metals break into two categories – ferrous and non-ferrous, where ferrous metals originate from iron while non-ferrous have no iron.

Ferrous metals – Steel, which is primarily iron, can be roller formed without having to be heated. Stainless steel is ideal for the process because of its ductility. Galvanized steel, treated with zinc and is similar to raw steel, is able to be roller formed and has a protective coating.

Non-ferrous metals – Many of the non-ferrous metals can be easily roller formed since they are soft and very malleable. They include aluminum, brass, and copper. Aluminum is the first selection because it is very lightweight, soft, and pliable. Once roller formed and exposed to the air, it forms a protective layer of aluminum oxide. Brass is in the same category along with its close relative bronze. Of the non-ferrous metals, copper is very ductile and ideal for roller forming as well.

Uses of roller formed products

Roller formed parts can be found in every building, vehicle, and home. Anything that has a long piece of metal that forms a specific shape has most likely been roller formed.

Window and curtain tracks – Using aluminum or steel, long lengths of tracks for windows are roller formed. When you open and close a window you can see them on the side of the casement. This is also true of the tracks a car window runs up and down in.

Rain gutters – A major development in the use of rain gutters was the use of roller forming seamless gutters that could be fitted exactly to the dimension of a house. Roller forming made it possible for the gutters to be completely sealed to avoid leaks. Later, gutter protective covers became another product from roller forming.

Siding – Metal siding is painted or coated before being roller formed. Galvanized steel or aluminum are the main metals used in this process at a 0.4 to 0.6 mm gauge. The machine is programmed to cut the lengths of siding required for the project. Included in most roller forming of siding is some form of concealed fastener. The process is very quick and efficient producing a product that will last for years.

Air ducts – Since ducting has to be long and strong, the metal used is galvanized steel at 20 to 30 mm flange. Once the metal has been roller formed, it is cut into the desired lengths. The process requires approximately 16 rollers to reshape, bend and form the ducting product.

Angle irons – Of all of the roll-formed products, angle irons are the most basic and easiest to manufacture. Unlike the more complicated process such as gutters, angle irons require very little engineering or a complex system of rollers. The number of rollers required depends a great deal on the thickness and type of metal.

Other roller forming machines

Though multiple roller forming machines are very common, roller forming is not restricted to just one type of equipment. There are single roller machines that can be operated manually or electronically. These types are capable of reshaping very thick pieces of metal usually into round cylindrical forms or shapes. They require several adjustments during the reshaping where the metal goes back and forth through the machine to form a perfect circle. The completed pieces are used as pipes, storage bins, car, and motorcycle exhausts, and other situations were tubing is required.

Whether the machine has a single or multiple rollers, it requires more time than traditional roller forming. The metal products produced are not long like those that come from multi-roller equipment.

Final word

Roller forming is a very inexpensive way to produce large quantities of a product. It can produce any kind of item that is long and has a particular profile. Also, the machines can be repurposed and reengineered to fit several kinds of parts with a variety of metal thicknesses.