ELEKTROCHEMISCHE MASCHINENBEARBEITUNG

PCT No. PCT/GB92/00229 Sec. 371 Date Sep. 29, 1992 Sec. 102(e) Date Sep. 29, 1992 PCT Filed Feb. 6, 1992 PCT Pub. No. WO92/13667 PCT Pub. Date Aug. 20, 1992.A method of electrochemically machining a workpiece made of electrically conductive material so as to provide a radius on an edge of the workpiece comprises, (a) providing a cathodic tool comprising a cathode section sandwiched between two anode sections and separated therefrom by insulation, (b) locating the tool adjacent to but separate from the workpiece so that the cathode section is positioned centrally over the edge of the workpiece to be radiused and the anode sections lie facing opposite sides of the edge, (c) causing electrolyte to flow between the tool and the workpiece, (d) applying a cathodic voltage to the cathode section, (e) applying preselected anodic voltages simultaneously to the workpiece and the anode sections so that electrical field null points between the cathodic tool and the workpiece lie either side of the edge to be radiused, and (f) varying the electrical field between the tool and the workpiece so as to cause the null points in the electrical field to move with respect to each other and said edge of the workpiece to ensure an overall energy distribution across said edge to create the radius required.