Air Bending v. Coining

Used for creating V, U, or channel-shaped bends in ductile material, usually sheet metal, bending is a basic manufacturing process. Air bending and coining are two of the most commonly used bending processes.

Unlike in coining, punch tips never fully contact the workpiece in air bending. Instead, metal is bent when it is forced into a bottom V-die opening. Bend radii thus depend on the size of this opening, not the bend radii of punch tips, meaning air bending gives manufacturers more flexibility and design options than coining. In addition, because air bent radii can be changed simply by changing the bottom dies, manufacturers can more easily fix layout mistakes.

Because air bending requires less bend force and tonnage than coining, it also uses smaller tools and fewer tool changes, leading to increased productivity. But because air bent sheet metal does not come in full contact with dies, precision and accuracy rates are lower than in coining. And while greater variety in materials, thicknesses, and angles is possible with air bending, this greater variety and the resulting wear on tools can lead to more defects.

Both processes meet the demanding quality requirement of industrial sheet metal tolerances but can be implemented differently depending on the required features and target cost.