Press Brakes
Press brakes are stationary machines for processing sheet metal. Smaller presses can be operated with a manual lever mechanism. Professional, large-format presses operate hydraulically.
Operating Principle
Press brakes exert linear pressure on the inserted sheet metal. This pressure stresses the metal beyond its yield strength, creating a permanent edge. This is how press brakes get their name: they form edges in sheet metal.
However, the press brake does not cut the metal, and the sheet retains its full size and weight.
Structure
A press brake consists of:
- A work table or material guide
- An integrated measurement system
- A bending tool
- A lifting and bending mechanism
- A drive system
The work table (material guide) serves to support the sheet metal securely and without deflection. Only in this flat position can the sheet metal be measured correctly. For this purpose, millimeter measurements are integrated on the side of the work table or material guide.
The bending tool is usually permanently integrated in smaller press brakes.
Larger, hydraulic press brakes have interchangeable tools, in the form of linear, V-shaped inserts. Depending on the size of the V-angle, different angles can be formed in the material to be bent.
The lifting and bending mechanism depends heavily on the type of press brake. A distinction is made between two types:
- The swing beam bending machine: here, the sheet metal to be bent is allowed to protrude beyond a straight edge. A strong bending beam above the work table is moved downwards in a swinging motion, bending the sheet metal in the desired direction.
- The press brake with a die: is equipped with interchangeable working tools. The sheet metal is inserted between the tool halves. The die is lowered, forming the sheet metal in the desired way.
In smaller press brakes, the lifting mechanism consists of a lever system with counterbalanced weights and can be easily moved by hand.
Large press brakes have a hydraulically driven lifting mechanism. Accordingly, manual press brakes do not require an electro-hydraulic drive. Hydraulic press brakes are operated by an electrically driven hydraulic pump.
Application
Small, manual press brakes are primarily used in smaller locksmiths and automotive workshops. They are used for fabricating sills and other body panels. Simple housings and angles can also be produced on these machines. Manual press brakes are often offered in a combination of a bending machine and a sheet metal shear. However, their application range is severely limited in terms of the size and thickness of the material that can be used. Typically, the maximum sheet metal thickness that can be processed on manual bending machines is one millimeter.
With hydraulic press brakes, there are practically no technical limits to processing material in terms of shape, size, and thickness of the sheet metal. Industrially applied machines of this type can therefore reach enormous dimensions. A famous example of the performance of press brakes can be found in Siegen at the Pickhahn company. There, the steel sculptures of sculptor Richard Serra are produced on a former French press brake, which was previously used to produce the pressure hulls of submarines.
In addition to large-format hydraulic press brakes, automation and demand-oriented configuration have also continuously evolved in this technology. Press brakes for the serial processing of sheet metal parts are therefore standard in many production lines today.
Additions
A press brake is ideally complemented by a guillotine shear and a loading aid, for example, in the form of an industrial robot.