Industrial metal bending is where sheet bending takes place at a much grander and larger scale than fabrication shops. In industries focusing on metal bending, there is a huge volume of metal that needs to be processed and the processes could be intricate. There are specialized machine presses that allow these industries to bend metals in the desired angles and shapes. There are three types of bending that takes place on a press break. These types of bending are solely defined by the thickness of the material and the end tool position.
Air bending is a method where the metal is bent using a punch. A punch is pressed into the material and in turn it is forced into a bottom V die, which is mounted on the press. This punch forms the bend and since air bending uses less force, it makes use of smaller tools than other types of industrial metal bending processes. The only disadvantage with the air bending process is that since the metal is not in full contact with the die it is not very precise and the stroke depth has to be kept accurate. Wear and tear on the tools as well as the variations in the thickness of the metal could result in defects being produced in the metal parts produced.
Bottoming is a technique where the metal sheet is forced onto a V shaped opening with the bottom tool. In this method U shaped opening cannot be used and the advantage here is the accuracy of the job. However the disadvantage here is that different set of tools is required for different materials, different sheet thickness as well as different bend angle.
Coining is a process whereby a top tool is used to force the metal sheet into the bottom die with force that is much higher than what is used in air bending. This method tends to cause permanent deformation to the sheet and even though it is very precise, the costs involved are huge.
In roll bending there are three rollers that are used to bend the metal sheet into a circular arc.
In this process, the V shaped die in the bottom is replaced by a flat pad of rubber or urethane. When the punch is pushed onto the metal the bottom flat pad deflects and allows the metal to form around the punch.
These are some of the metal bending techniques used in industries.