Sunday, October 27, 2013

All About Bending Machines

Bending machines are used to create sheet metal through a mechanical brake. There are many different kinds of bending machine breaks depending on the type of sheet metal desired. Obtaining the perfect kind of bending machine will increase press brake productivity.
A brake is a metalworking machine which allows for the bending of sheet metal. The brake has a flat surface where the material is placed. A clamping bar comes down to hold the material firmly during a bend. The clamping action can be manual, automatic, or operated with a foot pedal.
The machine has a front, gate-like plate which is hinged. It is lifted in order to force the material to extend over a straight edge in order to bend to follow the plate. The bends can be any angle, but the practical limit is 120 degrees. If the area to be bent is narrow enough, a sharper bend can be made by inserting the bend under the clamping bar and lowering it.

Bending produces V-shape, U-shape, and channel shaped sheet metal along a straight axis. For press brake forming, the sheet metal piece is positioned over the die block. The block presses the sheet to form one of the previously mentioned shapes.
Usually bending has to overcome tensile and compressive stresses. After bending, those residual stresses cause the sheet metal to spring back towards its original position. This means the sheet metal must be over-bent to achieve the appropriate bend angle. The amount of spring back is dependent on the material and type of forming.
When the sheet metal is bent, it stretched in length. The bend deduction is the amount the sheet metal will stretch when bent. This is measured from the outside edges of the bend. The bend radius is the inside radius of the bend. The bend radius that is formed is dependent on the dies used, the material properties, and material thickness.
There are four kinds of brakes in a bending machine. These include a cornice brake, box and pan brake, bar folder, and a press brake. The press brake is the most complex tool but the most efficient. It forms predetermined bends by clamping the work piece between a matching punch and die.
The best brand for a press brake in a bending machine is Wilson Tool. Their precision, performance, and innovation is state of the art. This allows producers to become the best fabricators in the world. They have an innovative Nitrex high endurance surface enhancement that extends the life of tooling several times over an untreated tooling.
Wilson Tool has urethane products that help press brake operators reduce or even eliminate sheet marking during bending operations. These are mark-free bending solutions which include urethane dies, holders, pads, and rolls. The solutions save operators time by eliminating the need to clean up unwanted marked on sheets after bending.
Urethane dies are available in American Precision and European style. The dies greatly reduce, and in some cases completely eliminate, sheet marking on the press brake. Urethane holders are manufactured using 6061-T6 aluminium, holding a pad of urethane for mark free and radius bending.
Two pad hardness options are available. The most commonly used one is Blue/90A. The Red/80A helps reduce tonnage in the application by about 20 percent. Urethane rolls provide a protective layer across the top of standard dies to prevent sheet marking. They are also available in two styles.
The standard roll of urethane is available in thickness of.4mm or.8mm, depending on the application. There are also high-density urethane rolls are.55mm thick and last significantly longer than standard urethane.

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