Linear forming of sheet metal: Press Brake
Bending is a machining process that belongs to the group "forming". It is characterized by its linear and tool-less machining method. The processing possibilities of bending are limited and available only for very specific semi-finished products. Nevertheless, it is one of the most widespread forming processes and is widely used.
How bending works
For bending, the so-called "bending bench" or "press brake" is required. This machine tool is available in numerous designs. Simple, manual bending benches are operated by muscle power. Edging benches with manual-hydraulic support can already process thicker sheets. In series production, pneumatic or hydraulically operated edging benches are the standard.
Bending benches are offered in two designs:
- Swivel bending benches
- Press Brakes
Swivel bending benches consist of a flat table and an attached bending unit. The sheet is pushed over the flat table through the bending unit. The bending unit swivels with the help of a counterweight and bends the sheet in the desired direction. The bending angle can be freely selected up to 155° on a swivel bending bench.
Swivel bending benches are very durable and require little maintenance. Fast results can be achieved with them and they are inexpensive to purchase. However, only thin sheets can be sensibly processed on these processing machines.
Press brakes consist of a flat table or a roller feeder to which a linear press is attached. This press consists of two v-shaped die halves. The sheet metal is pushed between the mold halves. The press then moves together. The deeper the mold halves come together, the more the sheet is bent. The bending angle is limited to the angle of the mold halves.
Press brakes are the standard machines for bending in the industry. They are suitable for manual or serial production. These processing machines can assume enormous dimensions. Their particular advantage is that, in addition to bending sharp angles, they can also work radii into sheet metal. Due to the exchange of the mold halves, press brakes are very flexible and offer a wide range of possibilities for forming.
Complements to the press brake
A press brake is often supplemented by a plate shear. This allows the workpiece to be shortened to the desired dimension immediately after bending. In the case of swing-bend benches, these cutting devices are designed as impact shears. For bending thick sheets on press brakes, thermal or abrasive cutting processes must be used. Combined machines that unite both work steps are available, but belong to special machine construction.