Method and device for electrochemical machining of a metallic workpiece

Abstract

A device for electrochemically machining a metallic workpiece (30), comprising: a clamping device (10), an electrode (14) fixedly arranged in the clamping device (10) for electrochemically machining the workpiece (30), a workpiece holder (16) arranged on the clamping device for receiving and positioning the workpiece (30) relative to the electrode (14), means (20, 22, 28, 62) for supplying an electrolyte (38) into a working gap (34) between the electrode (14) and the workpiece (30), and means for applying an electrical voltage between the electrode (14) and the workpiece (30); characterized by means (20, 22, 38) for automatically centering the workpiece (30) in the workpiece holder (16), wherein the workpiece (30) is held freely movable in the workpiece holder (16) by means of a hydrostatic compensating device and is automatically centered relative to the electrode (14).

Claims

[1] Device for electrochemically machining a metallic workpiece (30), comprising: a clamping device (10), an electrode (14) fixedly arranged in the clamping device (10) for electrochemical machining of the workpiece (30), a workpiece holder (16) arranged on the clamping means for receiving and positioning the workpiece (30) relative to the electrode (14), Means (20, 22, 28, 62) for supplying an electrolyte (38) into a working gap (34) between the electrode (14) and the workpiece (30), and Means for applying an electrical voltage between the electrode (14) and the workpiece (30); characterized by Means (20, 22, 38) for automatically centering the workpiece (30) in the workpiece holder (16), wherein the workpiece (30) is held freely movable in the workpiece holder (16) by means of a hydrostatic compensation device and is automatically centered relative to the electrode (14). [2] Apparatus for electrochemically machining a metallic workpiece according to claim 1, wherein the apparatus is used for introducing bearing groove structures into the surface of a bearing component of a fluid dynamic bearing. [3] Device according to claim 1 or 2, characterized by in that the means for automatically centering the metallic workpiece comprises a hydrostatic compensating device, wherein a fluid (38) is introduced under pressure into an intermediate space (36) between the workpiece holder (16) and the workpiece (30). [4] Device according to one of claims 1 to 3, characterized bythat the surfaces of the clamping means (10), the electrode (14) and the workpiece holder (16) facing the workpiece (30) can be machined together in one clamping after their assembly and can thus be aligned with one another. [5] Device according to claim 3 or 4, characterized by that the fluid (38) for centering the workpiece (30) is at the same time the electrolyte (38) for electrochemical machining of the workpiece (30). [6] Device according to one of claims 3 to 5, characterized by that the intermediate space (36) is connected to the working gap (34). [7] Device according to one of claims 3 to 6, characterized by that the gap (36) between the workpiece holder (16) and the workpiece (30) is a gap with a gap width of 20 - 50 micrometers. [8] Device according to one of claims 3 to 7, characterized bythat recesses (20) are provided in the surface of the workpiece holder (16) facing the workpiece (30), into which bores (22) open, via which the electrolyte (38) is fed into the intermediate space (36) between the workpiece holder (16) and the workpiece (30). [9] Device according to one of claims 1 to 8, characterized by that the workpiece holder (16) comprises a recess for receiving the workpiece (30). [10] Device according to one of claims 1 to 9, characterized by that a stopper surface (11) is arranged on the clamping device (10) as an axial stop for the workpiece (30). [11] Device according to one of claims 1 to 10, characterized by that the device has a second inlet (28, 62) through which the electrolyte (38) is fed into the working gap for electrochemical machining of the workpiece (30). [12] Device according to one of claims 1 to 11, characterized byin that the clamping device (10) comprises a concentrically arranged metal bushing (58), wherein the metal bushing (58) can be electrically contacted from the outside on the one hand and can be electrically connected to the workpiece (30) to be machined on the other hand. [13] Method for electrochemically machining a metallic workpiece (30), comprising the steps: Providing a clamping device (10) with an electrode (14) fixedly arranged in the clamping device for electrochemical machining of the workpiece (30), Inserting the workpiece (30) into a workpiece holder (16), and Electrochemical machining of the workpiece (30) by supplying an electrolyte (38) into a working gap (34) between the electrode (14) and the workpiece (30) and applying an electrical voltage between the electrode (14) and the workpiece (30), characterized byan automatic centering of the workpiece (30) in the workpiece holder (16) by means of a hydrostatic compensation device, wherein a fluid (38) is introduced under pressure into an intermediate space (36) between the workpiece holder (16) and the workpiece (30). [14] Method according to claim 13, characterized by that electrochemical machining comprises the introduction of bearing groove structures into the surface of a bearing component of a fluid dynamic bearing.

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