Innovative sheet metal folding machine makes inroads into Europe

A new concept in bending sheet metal machine, launched in South Africa last year, is enjoying success internationally. Electrabrake machines, manufactured locally, clamp sheet metal magnetically and are revolutionising the concept of sheet metal bending worldwide, says Unique Engineering’s Electrabrake sales manager Brian Robertson. “The machines are the result of looking at the steel sheet-bending market worldwide and sales to the US, Canada, the UK and Europe are surpassing all expectations. We are very excited about the prospects of the product in South Africa and abroad,” he says. The company is launching six models, with bending lengths varying between 625 mm and 3,2 m. Mild steel sheets of up to 1,6 mm and stainless-steel sheets of up to 1 mm can be processed along the full length. Robertson says that even aluminium and other nonferrous materials may be processed because the machine is essentially a long electromagnet with a steel clamp bar positioned above it. The magnetic clamping force passes through all materials and pulls the clamp bar onto the sheet. Work pieces are clamped between the bar and the magnet by a force of several tonnes, ensuring precision bending. “Magnetic clamping allows bending loads to be taken precisely at the point where they are generated, which means that forces do not have to be transferred to support structures at the sides of the machine. This makes it unnecessary for the clamping bar to have extensive structural mass and its compactness means that it does not obstruct the bending operation. “The thickness of the clamping bar is, in fact, determined only by the need for it to carry enough magnetic flux and not at all by structural consideration,” Robertson says. Bends are formed around the front edge of the bar when the handle of the rotating beam is pulled up. The angle of the bend is read from a graduated scale and adjusters at the end of the bar allow easy adjustment of the bend radius for varying thicknesses of work pieces. Centreless compound hinges were specially developed for the Electrabrake machines. These are positioned along the length of the bending beam and, like the clamp bar, take bending loads lose to where they are generated. These hinges, combined with the concept of magnetic clamping, make it possible for the machines to be ganged end-to-end to process long work pieces. The clamping force is automatically released once the handle is returned to its original position and the work piece may then be removed or repositioned for further bending. The bar may be manually lifted to any required height to insert work pieces that were previously bent, for further processing. Safety features include immediate release of the bar if the rated capacity of the machine is exceeded to avoid damage to the machine. Standard accessories include backstops to locate the work piece and a set of short clamp bars that plug together. Other accessories include slotted bars for forming shallow boxes faster, narrow clamp bars, foot switches and power shears with a guide to ensure straight cutting without distortion of the material. Robertson says operators can quickly make special tooling from pieces of steel to help fold intricate shapes. The standard clamp bar can also be replaced by specialised tooling for production work.