Air bending and bottom bending are the two most common processes used to create bends in sheet metal manufacturing.
The final implementation of each process is as you can see in the bending process.
Of course, these two processes are not unfamiliar to those in the industry, but they are relatively unfamiliar to those who know the industry, so Mulan Group will introduce the differences between air bending and bottom bending and their corresponding use scenarios in detail below.
Difference between air bending and bottom bending
Both air bending and bottom bending are performed using the same bending equipment: dies and punches. The difference between these two bending methods lies in the technology used when bending. Bottom bending is to press the part completely to the bottom of the die to form an angle. Air bending is to press the part partially down on the die to form a given angle, such as 20 degrees. The die has a total of 60 degrees, and the air bending process only requires 20 degrees, so there is still a gap between the part itself and the bottom of the die.
Bottom bending can be used to complete bends in metal parts that require higher precision. Air bending is slightly less precise than air bending, but accuracy can be achieved with angled molds. For quicker operation, air bending can be used to complete sheet metal projects without specific high precision requirements.
Both bending processes can be performed manually or with a press brake. Of course, air bending requires a more precise press brake. However, for bottom bending, the accuracy of the press is less important, but more scrap may be generated. Bottom bending may also require more equipment maintenance due to the pressure applied to the die and the impact on the press brake hydraulics.
What is air bending?
For air bending, the press brake is equipped with a punch tool that is used to apply pressure to the metal sheet. A V-shaped bottom die is used below the punch tool to support the metal during the bending process. To form the bend in the metal, the punch presses the material into the bottom die until the correct bend angle is achieved.
Air bending is called air bending because the metal sheet is not fully pressed into the die during the bending process. Instead, as shown in the figure above, air is left between the metal sheet and the die. With air bending, there are only three points of contact at all times during the bend: one on each side of the top of the V-shaped opening of the die and one at the tip of the punch.
Because the sheet metal is not pressed to the bottom of the die, the shape of the die does not define the angle of the bend. Instead, the depth to which the metal is pressed within the die determines the angle of the bend.
With air bending, the same die can be used to accommodate a range of bend radii and bend angles. Any radius and angle that fits the punch profile and depth is achievable. A wide range of materials can also be accommodated.
A common challenge with air bending is that the bend will experience more springback than other bending methods. This is when the metal bends slightly toward its original shape after being bent. The angles are also not as accurate as with bottom bending. One way to overcome the inherent issues with air bending is to use laser measurement technology that helps improve accuracy.
What is a bottom bend?
A bottom bend also uses a punch and a V-shaped bottom die, just like an air bend. The difference is that the punch is used to push the metal completely into the die to form the bend. A bottom bend, or bottom bend, gets its name because the metal is pressed to the bottom of the die. Using higher pressure, the metal is in full contact with the punch and die.
Because the material is pressed into the bottom of the die, the die used will determine the bend angle achieved. With bottom bending, you must change the die to achieve different bend angles. This is not the case with air bending, as the punch can be pushed to different depths in the die.
Bottom bending reduces springback and produces more precise angles. The biggest disadvantage is that each new bend radius requires a different bottom die, which means it needs to be manually changed on the machine. The machine is also under greater pressure during production.
The above is a detailed introduction to these two sheet metal bending processes. Of course, if you need a large number of sheet metal bending services, or you are a trader, you can look for Mulan Group to help. As a professional sheet metal parts manufacturer in China, Mulan Group provides OEM services for various sheet metals, including stamping, cutting, bending, and surface treatment. We support turnkey services, you only need to tell us your needs, and you can sit back and wait for delivery.
Here is our Sheet metal bending sample display：
