Optical inspection method for determining machinability

摘要

In a method for determining the machinability of a metal substrate for use in an electromechanical recording apparatus a surface of a foundation is coated with a layer of metal. The metal layer is machined such that the metalized surface of the foundation is substantially flat and smooth. After the machining step, the metal surface is inspected for depressions with a microscope using a differential interference contrast technique. The number of depressions observed is indicative of the machinability of the coated foundation.