Metal covers look simple, but the forming process is not always easy. A cover may need a clean round edge, stable wall thickness, smooth surface, accurate diameter, and enough strength after shaping.

A metal spinning lathe machine is a forming system that reshapes a flat metal blank or preform over a rotating mandrel to produce axisymmetric parts such as cones, hemispheres, cylinders, reflectors, cookware bodies, ventilation components, and pressure vessel ends.