When one considers ways to bend a large channel flanges-out to a minimum bending radius, doing a mandrel bend is one alternative. A recent requirement was for more than 200 rolled channel, bump protectors to cover cement columns in an airport. The design called for MC12 x 10.6 curved to a very tight 12-1/2 inch inside radius in 180 degree segments.
Using a rotary draw machine to do a mandrel bend would provide good productivity and quality but would require the development and manufacturing of a special set of tooling. (Most bending companies would not have tooling for this unusual size.) The customer’s very tight delivery schedule, however, did not allow time to make the tooling.
Another way to make these parts was considered: rolling the channels on a three-roll section bender. Like a mandrel on a rotary draw bender, the tooling on the three-roll bender would support the web of the channel. But when the company referred to its records of previous work like this, it looked like this method would not yield the quality and productivity needed even though the tooling was already made.
Curving these channels on a specially designed plate roll was also considered and that method turned out to provide the best quality, productivity and short turn-around time. A template was made to ensure the needed quality.
If a bending company has a wide range of similar machines and a wide range of machine types, it is often the case that alternate methods to produce a curved steel section can be explored. It is beneficial, for example, to match the right size section bender to the steel section to be bent. Having separate machines to bend 1×1 angle, 2×2, 3×3, 4×4 all the way up to 10×10 angle, to give one range of sizes and sections, allows such a company to put the material on the machine that will best minimize the trim or waste at the end of the rolled section while providing the highest quality, productivity and fastest turn-around time.
Furthermore, if a company has a wide range of machine types, it can explore alternate methods to create a curved steel section. Bending companies might have rotary draw machines, three-roll section benders, plate rolls, ram benders, press brakes, and other machines to curve steel. To the degree that a company has some or all of these machines and knows how to use them, to that degree it can be the most versatile in providing solutions to its customers’ steel bending requirements.