guest editorial
the Rolleri Vario

With the Rolleri Vario, average setup time can drop by as much as 85 percent.

Tested Tough
Adjustable die system equips a press brake with a single tool that can be easily changed, eliminating time-consuming, heavy handling
By Julio Alcacer, sheet-metal fabricator specialist, Rolleri USA

very aspect of the global economy has been tested in the past decade, and the fabrication sector has not been exempt from the challenges. With booming gas and energy costs, environmental requirements and increased efficiency needs of modern industry, abrasive-resistant (AR) steels have evolved as a major contributor for countless applications, despite having been around for a while.

In fact, all indicators point to the need for even lighter, more durable, reliable and efficient trucks, tractors, mining equipment and other products that require abrasive-resistant steels. However, fabricating these materials can be a challenge. Abrasive-resistant steels are much harder, making them difficult to penetrate, resistant to traction and less ductile, which means they can crack much more easily than mild or stainless steel during processing. In order to properly bend a part made from abrasive-resistant steel, fabricators must step up both their equipment and knowledge.

Bending AbRasion resistant steels requires strong tools.
Heavy-duty tools

A press brake with enough tonnage to handle the material is a necessary starting point, but it will not be enough without the proper tooling. Bending abrasive-resistant steels requires strong, large-radius tools, large V openings and the ability to go past the desired angle of between 15 and 20 degrees. Some AR steels can spring back as far as 25 degrees.

Abrasive-resistant steels require an average V opening factor of 10 times to 14 times the thickness of the material, which means that large V openings are needed, and the ultimate tensile strength can easily go up to 1400 MPa, which means that V openings, and tools in general, will need to withstand a lot of pressure. Finally, because large-radius upper tools are needed to bend abrasive-resistant steel without cracking, fabricators will witness a lot of springback when fabricating parts.

Adjustable V opening dies, such as the VARIO adjustable die from Rolleri, usually have substantial success in these tough applications. A typical part for the automotive, mining or heavy equipment industry can be 26 feet long, which requires the use of a large die in the bending process. It is extremely time consuming to exchange all those dies with a different V opening every time a new part with a different thickness is loaded.

Quick change

Time is money, and that is why fabricators need a fast, easy and reliable way to exchange their dies when working with abrasive-resistant steel.

The Rolleri VARIO adjustable die was specifically designed to work with abrasive-resistant steels. It allows fabricators to achieve a high ton/foot pressure while providing the extra 20 to 30 degrees needed to compensate for springback. Exchanging the V opening takes just a few seconds, thanks to a patented system that only needs to use a job shop’s compressed air line.

Rolleri has run myriad tests on the die. The larger version, which goes from a 2-inch to 16-inch opening, obtained 90 degrees both on 0.85-inch-thick Hardox 450 and a similar part made from 1.25-inch-thick grade A36.

Changing dies is fast, easy and can be done by a single operator. The shoulders are made of quenched and hardened long-lasting steel, specifically selected to prevent excessive wear when processing abrasive-resistant steels. The structure of the die, while light and fast to move, is made in S700 steel and cut in a shape that guarantees a 100 ton/foot resistance.

Long story short: Those who fabricate abrasive-resistant steels or who are thinking about adding this capability should make sure their equipment is up for it.

Rolleri USA, Avon, Ohio, 440/835-2580,