Method and device for threading electrode wire in electrical discharge machine tools

摘要

The threading method works with a directed liquid jet (34), inside which the initial section (32) of an electrode wire (30) put in comparatively slowly is guided through the working space with a correspondingly brisk relative movement and therefore corresponding drive force. This relatively high drive force results in a certain longitudinal tensioning of the wire and thus keeps it straight during the threading operation. The liquid jet therefore continues throughout the threading operation and accordingly is free of disturbance during the intermittent jet build-up. The device used accordingly has a nozzle connected to a source of pressure liquid and directed into the working space, the electrode wire in the nozzle outlet area being arranged coaxially to the nozzle openings and being held coaxially in the continuous liquid jet.