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Sheet metal bending (or press braking) can be done with different types of sheet metal bending machines of which the press brake is the most common and all-round type. Sheet metal bending is done by inserting a sheet metal workpiece between two press tools, a so-called puncher and bench. By pressing the tools (which are shaped to match thickness of material and angle) together with great force, the sheet metal workpiece is bend in the ordered angle and outline.

KK Metal has several press brakes, all CNC operated. With the option of a bending length up to 4 metres, with 9 axis’s CNC operated, we can bend very complex plate workpieces in one mounting and in the same bending process or working operation.

Sheet metal bending – precision and high quality

The principle of bending sheet metal is a simple process. But only in principle, as modern sheet metal bending in practice requires a high level of precision, quality of material and not to mention experience. Despite the fact that sheet metal bending machines (including a press brake) work very accurately, typically within 1/100 mm, the tolerance and the quality of the materials remain a challenge.

With sheet metal bending, a radius (bend) will always remain, as it is not possible to bend in radius 0. This radius (the bending radius) has to have a minimum value, which is connected to the properties of the material. With thinner, common types of steel and stainless steel, the radius (the “inner” radius in the bend) should be at least the same as the measured thickness of the sheet metal workpiece, e.g. a workpiece with a thickness of 2 mm cannot be bend with a inner radius less than r=2. Thus, when constructing a sheet metal item with a bend, the so-called bend supplement must be calculated, i.e. the material, which is “used” in the bend, is added to ensure that the workpiece can be bend in the desired final measurements. The bend supplement relates to the thickness of the material, the property of the material, and the desired radius. E.g. an aluminium workpiece and a stainless steel workpiece of the same thickness do not have the same bend supplement because of the material property.

KK Metal has many years of experience with sheet metal bending, and we work systematically with the bend supplement calculated from material, thickness, bending angle and other factors.