Sheet metal bending is a process whereby the end product is a single piece of sheet metal that is no longer flat.  It may have a single bend or multiple bends.  The bend(s) may be different radius’s from sharp 90 degree bends with large 2″ – 12″ radius’s that create a more rounded and softer edge.  Sheet metal fabricators make these bends on machines called press brakes with different types of tooling that allow the specified bend angle and radius to be made.

 

 

There are three basic types of metal bending on a press brake:  Air Bending, Bottom Bending, and Coining.

 

Air Bending

This is the preferred method of bending for most sheet metal fabricators.  It generally requires less machine tonnage to bend the metal and is easier on the tooling.

Air bending is the process of bending metal by the metal is placed between the top punch and the bottom die to form the bend.  It’s called air bending because the metal does not get pushed all the way down to the bottom of the die.

The main disadvantage with air bending is that tight tolerances are difficult to maintain.

 

Bottom Bending

Bottom bending also uses the punch and die, except in this case, the material is pushed all the way to the bottom of the die.  Bottom bending requires more machine tonnage, generates less spring back, and creates tighter tolerance, more accurate angles.

The main disadvantage with bottom bending is that a different bottom die is required for each angle, making the bending process longer.  Additionally, custom tools may be required depending on the shape of the bend.

 

Coining

Coining is the next step in the process that applies maximum tonnage from the punch forcing the material into the bottom die causing permanent deformation along the bend line.  The benefits of coining are maximum accuracy and high precision and spring back is virtually eliminated.

The main disadvantage is the slower processing time resulting in higher costs.

 

 

Amtex Precision Fabrication

At Amtex, we leverage the power of automation to provide our clients with precise, high-end products in a cost-effective manner. If you need precision metal fabrication services, contact Amtex online or call our team at (281) 489-7042 today!