Press braking / brake forming

Brake forming is one of the oldest mechanical metal deformation process. During the process, a piece of sheet metal is formed along a straight axis. This may be accomplished by a "V"- shaped, "U"-shaped, or channel-shaped punch and die set.

Although press braking appears a simple concept, maintaining accuracy can often be quite difficult. Precision bending is a function of both the press, the tooling, and the work-piece material. Material properties such as yield strength, ductility, hardness, and the condition of the material, all affect the amount of spring back of the material.

The most common industrial press braking process is called air bending. Air bending relies upon three point bending. The angle of the bend is dictated by how far the punch tip penetrates the "V" cavity. The greater the penetration of the punch tip the greater the angle achieved.

The main benefit of air bending is that it uses much less force than other methods to achieve a 90° bend due to the leverage effect.

Characteristic of the metal brake forming process include:

●Its ability to form ductile materials,

●It's use in both low and medium production run applications,

●The need for minimal tooling,

●Its suitability to produce smaller parts,

●Its output of long workpieces using a "V", "U", channel, or other special punch and dies.

The illustrations that follow provides a two-dimensional look at a typical press brake setup. Note how the tool removes the notched part. The left side of the illustration shows the press brake in the open position and the right side shows it in a closed position, press braking the metal workpiece.

Brake forming can commonly form metals up to 10" thick and some machinery will form pieces as long as 20 feet.

The press braking process can produce a variety of shapes. Some of the most common shapes appear, two-dimensionally, in the table below.

Materials commonly used in the brake forming process include:

●Aluminum

●Brass

●Cold rolled carbon steel

●Hot rolled carbon steel

●Stainless steel

Tool materials for brake forming include low-carbon steel, tool steel, carbide, and hardwood.