One of the advantages of many metals is that they are relatively ductile; ductility ensures that metals bend before breaking. Because of their ductility, they can be formed into a specific shape and size. Metals become more versatile as a result because flat pieces of sheet metal must often be shaped to be useful. The press brake is one of the most common pieces of forming equipment used for this.
What is a press brake?
A press brake is a piece of manufacturing machinery that bends sheet metal. A press brake is typically narrow and long to bend large pieces of sheet metal. Sheet metal is bent in a press brake by lowering a punch onto sheet metal that has been placed on top of a die. A press brake can bend the metal several times until it reaches the desired shape.
What types of press brakes are there?
Bending sheet metal requires a large amount of force, and to achieve and deliver this force, the punch is lowered onto the sheet metal through several different methods. The methods of force application can be hydraulic, pneumatic, electric, or mechanical. The method of force application is often included in the name of a press brake (e.g. hydraulic press brake, servo-electric press brake).
Press brakes also vary in the amount of force they can provide. On a press brake, this is known as tonnage; it is a measure of tons of force that the press brake can deliver. Typically, hydraulic presses are used to achieve very high amounts of force, and pneumatic and servo-electric presses provide lesser amounts of force.
The various types of press brakes have varying speeds and accuracies. The most accurate press brake will be a servo-electric press brake. In addition, pneumatic and servo-electric press brakes are typically faster than hydraulic and mechanical press brakes.
What factors must be considered when using a press brake to bend metal?
Press brakes can make a wide range of bends on a wide range of metals. When designing a bending process, take into account the metal being bent, the die, the punch, and the bending force.
The metal type is important to understand because of the differing physical properties among metals. For instance, high-carbon steel will generally be less bendable by a press brake than many aluminum alloys because of the differences in ductility and strength. Metals typically have a recommended minimum bend radius that the material can be bent to without damaging it.
The die and the punch used on the press brake both have a large impact on the bending process. The die is hollow material that the metal is placed on top of before bending. It is a very hard and strong material that is near in shape to the desired shape of the metal being bent. The punch is a solid material that is lowered down onto the metal. Since the pressing action of the punch onto the metal and the die are what causes the metal to bend, both shapes must be accurately suited to the bending job. The correct metal shape following a press brake operation is dependent on the size and shape of the punches and dies. The dies and the punches are typically designed in such a way that they can be interchanged easily to accommodate a wide array of jobs.
Common applications for press brakes include:
- Panels for automobiles
- Airframes
- Furniture made of metal
- Metal containers
- There are numerous other sheet metal forming applications.