Deformation testing evaluates the effect that load has on the shape of a sample. It is the measurement of a sample material to withstand a permanent deformation and/or the ability of the sample to return to its original shape after deforming. Deformation is measured as the percent change in height of a sample, under a specified load, for a specified period of time. A spring test is a type of deformation test where a spring is compressed to an L1 and L2 height and the load measurement is taken at each point and compared to a specified load. Spring rate can be determined. Ball punch deformation is used to evaluate and compare the formability of metallic sheet material used in production conditions and is used for materials with thicknesses between 0.0008 inch and 0.080 inch (0.20 mm and 2.00 mm).