Breakout detection in fast hole electrical discharge machining

Abstract

Real time tracking of the working end of the tool in fast hole electrical discharge drilling process is not straightforward due to extensive relative erosion of the tool, which manifests as severe longitudinal and shape wear. This poses a problem in terms of sensing hole breakout as well as hole completion, with adverse implications on process productivity and component quality. To this end, this paper presents a scheme that concurrently monitors the back pressure of the dielectric fluid injected through the tool and the displacement of the machine tool ram, to detect hole breakout and completion, respectively. Implementation of such a system has the scope for significantly enhancing process output, particularly in applications that entail the drilling of a large number of holes.