Method and apparatus for positioning first and second objects based on a potential difference

摘要

A method and apparatus is disclosed for defining the relative positions of a first object (1) and a second object (2). In particular, a contact point can be estimated by detecting a variation of a potential difference between the first and the second object (1, 2) as the objects approach one another. The method and apparatus are particularly suited for use in an electrical discharge machine (EDM) that is controlled by a numerical control (NC) unit (4) for machining a workpiece (2).