This is a process by which metal can be bent by deforming the material and changing its shape.  During the bending process, the surface area of the material does not change much.  Bending takes place by using press brakes.  Larger and smaller presses are used depending on which kind of application is being used.  Many different shapes can be produced through the bending process.  The two main types are Air Bending and Bottoming or Coining.   Air Bending is completed with the punch touching the workpiece and the workpiece, not bottoming in the lower cavity.  Bottoming or Coining is the bending process where the punch and the workpiece bottom on the die.