Abstract: A workholder comprising a body comprising a fluid bearing and a fluid, wherein the fluid bearing is adapted to releasably retain a workpiece by maintaining the fluid in a gap between the workholder and the workpiece, wherein the fluid bearing is adapted to produce a radial and/or an axial force on the workpiece, and wherein the workholder does not include a mechanical interface to releasably retain the workpiece is disclosed. Also, methods of using and manufacturing the workholder are disclosed herein.

Abstract: An apparatus and method are provided for electrochemically etching grooves in a working surface. In an aspect, a frame holds a working surface about an axis and facing an electrode movable along the axis. The electrode, axially movable, has surface carrying a groove pattern to fix on the working surface. A source of electrolyte is pumped at a fixed static pressure rate between the surface of the movable electrode and the working surface. In an aspect, a support fixture supports the electrode for movement toward and away from the working surface with minimal frictional restriction. A force biases the electrode surface toward the working surface so that a gap through which the electrolyte flows between the surface of the movable electrode and the working surface is determined primarily by the static flow rate of the electrolyte and the force bias of the electrode toward the working surface.

Abstract: A fluid dynamic bearing is provided having a first surface having at least a first groove pattern formed therein; and the second surface having at least a second groove pattern formed therein; wherein one of the surfaces is configured to be rotated relative to the other surface. The groove patterns may be conventional patterns or patterns described herein. Further, the patterns discussed herein may be disposed wholly on each surface or may be divided between the two surfaces. The groove design is intended to be useable in either a journal, thrust or other fluid bearing design.

Abstract: To groove two regions simultaneously to different groove depths, a dual element/voltage electrode is disclosed. The electrode comprises an outer, cylindrical sheath element and an inner rod element separated by an insulator. Each element operates at a different voltage. The cylindrical element which grooves the conical bearing will, for example, operate at half the voltage of the rod element which grooves the pumping region, thereby achieving twice the groove depth.

Abstract: A system and method are described for radially positioning a workpiece for electrochemical machining. In one embodiment, a pressurized air chamber is configured to contain pressurized air. In addition, an expandable diaphragm is configured to position the workpiece radially relative to an electrode assembly in response to the pressurized air being released into the pressurized air chamber.

Abstract: A dual cone or single cone work piece is placed inside a pair of locating surfaces so that it is accurately held within a framework defined by these locating surfaces. A electrode is then inserted inside the cone, and is movable within the cone to accurately set the gap between the electrode which will find the groove pattern to be formed on the cone surface. An electrolyte is then pumped through the gap between the cone and the electrode.

Abstract: To groove two regions simultaneously to different groove depths, a dual element/voltage electrode is disclosed. The electrode comprises an outer, cylindrical sheath element and an inner rod element separated by an insulator. Each element operates at a different voltage. The cylindrical element which grooves the conical bearing will, for example, operate at half the voltage of the rod element which grooves the pumping region, thereby achieving twice the groove depth.

Abstract: An apparatus 245 and method are provided for electrochemically etching grooves 235 in an inner surface 215 of a hub 160 to form at least one fluid dynamic bearing. The apparatus 245 includes a cathode 250 having an electrically conductive substrate 270 with an outer surface 275 that corresponds to the inner surface 215 of the hub 160. The outer surface 275 has raised lands 280 corresponding to areas in which the grooves 235 are to be formed in the inner surface 215 of the hub 160. A layer of electrically insulating material 285 covers the outer surface 275 of the substrate 270 between the raised lands 280 to reduce etching of the inner surface 215 of the hub 160 in corresponding areas.

Abstract: A workholder for an ECM process comprises a set of jaws which define an interior workpiece holding region are mounted on the surface of a diaphragm which is movable under air pressure from a flat to a more generally spheroid shape with the injection of pressurized air between the diaphragm and a backing plate. As the air is injected, and the diaphragm becomes more spheroid, the jaws are moved a substantially equal distance away from the center axis of the workholding region. The workpiece, which typically incorporates or is mounted on a circular shaft, is placed in the center of the workholding region, and the air pressure is removed, causing the diaphragm to return to its original flat shape and the jaws to snap back to their original positions resting against the shaft.

Abstract: The present invention is directed to an apparatus 245 and method of etching grooves 235 in a shaft 175. In one embodiment, a cathode 250 is provided for electrochemically etching grooves 235 in an outer surface 215 of the shaft 175 to form a fluid dynamic journal bearing 225. The cathode 250 includes an electrically conductive cylindrical substrate 270 having an inner surface 275 that corresponds to the outer surface 215 of the shaft 175, the inner surface 275 having raised lands 280 corresponding to areas in which the grooves 235 are to be formed. A layer of electrically insulating material 285 covers the inner surface 275 of the substrate 270 between the lands 280 to preclude etching of the shaft 175 in areas between the lands. Preferably, the lands 280 are arranged so that the grooves 235 etched in the shaft 175 form one or more fluid dynamic bearings.