GB1062050A - Improvements in or relating to electrolytic shaping - Google Patents

Abstract

<PICT:1062050/C6-C7/1> <PICT:1062050/C6-C7/2> A fixture for holding a workpiece during electrolytic shaping by a movable electrode comprises means for holding the workpiece with its surface to be shaped clamped against electrode guiding means. Fig. 1 shows an electrode 32 which is advanced through guide means 60 to machine a groove or notch (26) Fig.5 (not shown) in a workpiece W shown as a turbine blade. The workpiece is clamped in position on support blocks by a resilient pad 96 which can be raised and lowered by a handle 82. Electrical contact is made with a flange of the workpiece by operating a handle 110, Figs.1 and 3, to bring a copper braid conductor 116 into contact with it. As illustrated in Fig.4 (not shown) the electrode 32 is solid. Its forward end, apart from the working tip (140), has a covering of insulating material (142), e.g. of epoxy resin. The clearance between the electrode surface and the walls of a passageway 138, Fig.3 (and Fig.4, not shown), in the electrode guide means is such as to prevent electrolyte leakage. Electrolyte from a supply 34, Fig.1, is pumped through a pipe 36 and hose 44 and thence through a reservoir 136, Fig.3, in the electrode guide means 60 and passageway 146 to a recess (144) Fig.4 (not shown) in the side of the electrode. It then passes through the gap between the electrode tip (140) and the workpiece W and exits through a passageway 150 which may contain a restricting valve to put back pressure on the electrolyte in the work gap. The electrode is advanced at a constant controlled rate. All the parts supporting the workpiece are of electrically insulating material. The whole fixture for holding the workpiece in position relative to the moving electrode is clamped at 170, Fig.1, on to a table 162.