Metal sheet bending is one of the practical fabrication procedures which is used for producing a V-shape, U-shape along a straight line. The bending process is also a practical production method for other industrial materials. The equipment that is useful for the procedure includes box and pan brakes, brake presses and other particular pressing devices. By utilizing the process, manufacturers can produce a wide range of products for different projects, from industrial to construction purposes.

Metal Sheet Bending Process

In the metal sheet bending process with a press brake forming, manufacturers place the working material over the die block and then press the sheet to fabricate it into the demanding shape. This fabricating process needs to overcome both tensile and comprehensive stresses. After completing the bending, the residual stresses can spring back the material towards its previous position. Thus the manufacturers must overbend it to achieve the appropriate angle. The quantity of spring back depends on the character of the material and the forming process. The bending process increases the length of the working piece. Another essential term is bend deduction referring to stretching measurement from the outside edges of the bend during the process. The bend radius, which depends on the using dies, material properties and thickness, refers to the inside radius of the working piece.

Metal Sheet Bending Types

There are three primary types of metal sheet bending process that manufacturers utilize on a press brake. Each type definition depends on the relationship of the ending tool position to the thickness of the working piece. These methods and techniques including Air bending, Bottoming and Coining. The configuration of the equipment for all three ways is almost identical. The die is a long rail tool that features a concave or V-shaped lengthwise channel that locates the outside profile of the fabrication. These tools are often stationary, and their placement is under the material on the base of the bending device. The other types of metal sheet bending that are also practical utilize special tools with unique designs or machines to perform the process, including three-point bending, folding, wiping, and rotary bending.

Air Bending

The air bending method can form sheet metal by pressing a punch into the material while focusing it on the mounted bottom V-shaped die. The process comprises the bend to create a distance between the sidewall of the V and punch to be greater than the workpiece thickness. Due to the fewer force requirements, this bending process tends to utilize smaller tools than other techniques. Manufacturers can create different profiles and products due to the adjustability of devices. One of the advantages of the air bending system is that it can bend the material at various angles. The downside of this fabricating method is that it is not ideally precise due to the lower contract between the sheet and the dies.


In the bottoming metal sheet bending process, the manufacturers force the material against the V opening in the bottom tool. Therefore, the U-shaped openings are not practical for this method. A particular space is required between the bottom of the start and the sheet metal. The most efficient width of the opening is 6 T, about 3mm thickness up to 12 mm thick metals. The curving limit must be at least 0.8 to 2 T for sheet metals such as steel. A more considerable bending radius requires almost the same force for bottoming as they need for an air bending system. The advantages of this method include less spring back and greater precision. The only disadvantage of the bottoming method is that it requires various toolset for each angle, thickness and material. Generally, the air bending is more efficient compared to the bottoming.


The coining method utilizes 5 to 30 times the force of the air bending technique to force the material into the bottom die with the top tool. With the unique technique of coining, manufacturers can cause permanent deformation through the material without a considerable spring back. This system can create an inside radius as low as 0.4 T with a 5 T width of the opening. However, the disadvantage of the coning method is its cost which is higher than other practical techniques.

Three-Point Metal Sheet Bending

The three-point method is a modern system that utilizes dies with adjustable bottom tools, and it moves the device with a servo motor. The hydraulic cushion is used to make the requiring adjustments between the upper toll and the ram. The method is exact and entails higher costs. Thus, it is practical for high-value niche markets.


Manufacturers utilize a clamping beam to hold the long side of the metal and rise and fold the working piece around a bend profile. The shaft moves the metal down or up, allowing positive and negative fabricating bend angles. However, the pitch is depending on the tool geometry and metal properties.


This method is similar to folding with a higher working pace. However, it has a tremendous risk of damaging the metal by producing scratches. The trouble is more considerable in sharp angles, but it will overcome the spring back.

Rotary Metal Sheet Bending

The rotary bending is almost like the wiping, but the top die features a freely rotating cylinder with the demanding shape cut into it, and it matches the bottom die. The roll contacts on two-point on the sheet, and it rotates to do the bending process. The rotary bending method is known as non-marking suitable for the painted surfaces, and it can create angles greater than 90 degrees in a single punch on standard press brakes.

Other methods are available for metal sheet bending fabrications such as roll bending, elastomer, and joggling which are less common than the methods above. However, some manufacturers still utilize these methods for creating different construction materials.