Sheet Metal Form Prototyping

Sheet metal form prototyping involves a wide range of processes that manufacture parts for a vast amount of purposes. Sheet metal prototyping processes are characteristic in that the metal being processed is plastically deformed to shape it into a desired geometry. In order to plastically deform a metal, a powerful force must be applied that will exceed the yield strength of the material. When low amounts of stress are applied to a metal, it will change its geometry slightly, in correspondence to the force that is exerted. 

Think of stretching a rubber band, then releasing it, it will go back to its original shape. This is called elastic deformation. Once the stress on a metal increases past a certain point, it no longer deforms elastically, but starts to undergo plastic deformation. In plastic deformation, the geometric change in the material is no longer directly proportional to stress and geometric changes remain after the stress is released; meaning that the material does not recover its shape. The actual level of stress applied to a metal where elastic deformation turns to plastic deformation is called the proportional limit, and is often difficult to determine exactly.