Sheet metal folding evolves
During the early 1990s a sheet metal bending machine began having a greater presence in the U.S. market. The technology wasn’t frequent stateside, although it had by that time long established itself in Europe. It hit the roofing and architectural fabrication market first, then steadily made its method to the precision and industrial segments.
It didn’t look anything just like a press brake, the dominant bending machine of metal fabrication. Additionally, it wasn’t a leaf (also known as hand, or box and pan) brake, long a staple of roofing and architectural fabricators. However its operation did resemble those of a leaf brake, having a leaf (or beam) rotating upward to bend up (and also at first, it had been always up) a flange.
Germans called it schwenkbiegemaschinen, translated as “swing bending machine.” American fabricators knew it as being the folding machine or, more casually, the folder. Why did the U.S. market evolve so differently from your European market? The solution involves war and Europeans’ affinity for metal roofs.
The Postwar Era
1950s postwar U.S. looked nothing like postwar Europe. Being a new superpower, the U.S. experienced a massive manufacturing base, developed to give the war machine, plus it had the folks needed to get it done. Around the industrial side of fabrication, the mechanical press brake was becoming the typical. The machines performed bottoming; which is, the punch “bottomed” to the base of the V die, forcing the sheet metal up against the die angle.
Architectural fabricators didn’t embrace bottoming using the mechanical press brake, and even for good reason. Most mechanical brakes used 90-degree dies almost exclusively. If the operator required to change an angle, he needed to change tooling-not so efficient for architectural panels that may demand a variety of angles in one part.
Then there was clearly the part marking. Unless a fabricator committed to urethane tape or tools, it couldn’t form a thin, sensitive part without marks or marring, something which architecturally exposed panels demanded. This became much more essential as the usage of prepainted sheets started to proliferate. Architectural shops produced large, long parts, hard to handle on the press brake rather than the safest to cope with because they whipped up throughout the bending cycle. Because of this, the hand brake dominated the architectural
Meanwhile, fabricators in Europe were after a completely different path. The Second World War left the continent in tatters, a generation of craftspeople gone. Something required to fill the space, as well as for many fabricators, both around the architectural and industrial side, that something was the metal folder. In the beginning it had been much like a leaf brake, just having a motorized leaf that swung upward and manual backgauges.
“After the war, the rebuilding in Europe began,” said Geoff Stone, CEO of Peachtree City, Ga.-based MetalForming Inc. “In the late 1940s and early 1950s, the Germans started putting motors on [leaf brakes]. A motor would lift the top beam and the other motor would move the bending beam towards the correct angle.”
The European standing-seam metal roofing market helped pour more investment into folding technology. An average folder’s design, using the upper beam slanted backward, gave clearance to fold tall, 90-degree flanges. If bending on just two opposite sides, folders effectively had no flange height limit (past the practical limitations of physically moving a piece inside and out from the machine). Many workpieces within the architectural world also required hemmed edges, that your folder could form without having a tool change.
From the early 1990s folding machines finally began to acquire a significant presence within the U.S. architectural fabrication market, a sector that relied a great deal on manual labor.
“In the first 1990s we found a market with metal roofers who had been essentially upgrading from the hand brake,” Stone recalled. “The folding machine made products seven times faster when compared to a hand brake, therefore it had been a no-brainer. It was a big business.”