Ex-cell-o Gmbh

Airfoil Textron Inc.

Edmund R Hinman

Richard A Jack

An electrolyte chamber includes a cathode movable in the chamber toward a workpart to machine same and spaced from a wall of the chamber by a transverse clearance space and further includes a sealing piston movable transversely in the chamber in opposite directions toward and away from the cathode to substantially close off or open the clearance space. The sealing piston includes one or more fluid passages extending therethrough such that electrolyte pressure exerted on the sealing piston is substantially balanced in the opposite directions of movement such that unbalanced electrolyte pressure forces do not prevent the sealing piston from closing off the transverse clearance.

Pressure balanced sealing pistons for cathodes in an electrolyte chamber

An electrochemical machine of the type having a workpart shroud around the workpart except for the portion thereof to be received in an electrolyte chamber with the shroud and electrolyte chamber substantially enclosing the workpart during machining is provided with opposing clamps on an electrolyte chamber member to cammingly engage opposite lateral sides of the shroud to hold it against the electrolyte chamber member to reduce high pressure electrolyte leakage. A venting conduit system is provided from the shroud through mated engaged surfaces of the shroud and electrolyte chamber member to an electrolyte drain in the electrolyte chamber to vent gases from the shroud during machining. Flow of high pressure electrolyte through the electrolyte chamber and drain creates a suction on the shroud interior to cause venting of gases, such as hydrogen, therefrom.

ECM machine with mechanisms for venting and clamping a workpart shroud

A workpart to be the anode for electrochemical machining by a cathode tool is disposed on a shaft having a free end. An electrical coupling housing is disposed on the free end for movement thereon between electrical contact and non-contact positions. A stop extends axially from the free end of the shaft on a connector rod. A fluid actuated piston/cylinder assembly is disposed on the connector rod between the electrical coupling housing and stop. When the piston is actuated, it extends to abut the stop and, as a result of the reaction force, causes the cylinder housing to bias the coupling housing in the opposite direction from piston movement to the electrical contact position to effect electrical connection between the coupling housing and free end of the shaft. The workpart shaft includes a peripheral toothed portion driven by a pinion gear to index the shaft and workpart thereon. A caliper type clamp mechanism on the yoke member supporting the workpart shaft is disposed to clamp sides of the driven portion after the shaft and workpart are in indexed position for ECM'ing.

Electrical connector and clamp mechanism for ECM workpart shaft

The cathode includes a machining surface, at least a portion of which comprises alternate layers or lamina of conductive and non-conductive material whose spacing and thickness are selected to reduce over-cutting on the workpart surface.

Partially conductive cathode for electrochemical machining

An electrolyte chamber for an electrochemical machine tool includes oposed cathodes movable in respective directions toward one another and toward a workpart therebetween and in respective transverse directions and sealing pistons each movable in the electrolyte chamber in a respective transverse direction to sealingly engage the side of a respective one of the cathodes. An electrolyte inlet is disposed between the sealing pistons, and the sealing pistons direct electrolyte flow toward the workpart between the workpart and cathodes and prevent electrolyte from by-passing around the cathodes.

Electrolyte chamber with cathode sealing means for ECM machining

In electrochemically machining individual oversize blades of an integral bladed gas turbine engine rotor, opposed cathodes are initially offset in an electrolyte chamber relative to a selected machining position with the rotor outside the chamber skewed at an angle relative to the final position of the cathodes in the electrolyte chamber. The rotor and electrolyte chamber are then relatively moved in a vertical direction to position an individual blade to be machined in a workpart machining position in the chamber and concurrently one cathode is moved in a direction toward one side of the blade and the other cathode is moved in two other different directions, one toward the blade from the opposite side of the blade and the other transverse thereto, to position the cathodes in aligned relation on opposite sides of the blade at the machining position with blades adjacent the individual blade to be machined received in pockets in the cathodes without contact. The cathode on the convex side of the blade is initially offset laterally and is moved bi- directionally whereas the other cathode on the concave side is moved in one direction toward the blade to be machined. The cathodes are advanced toward the respective side of the blade and toward one another from a cathode start machining position to a cathode finish position with electrolyte and electrical current flow between the cathodes and blade to effect machining and with the adjacent blades received in the cathode pockets out of contact. During this advance, the cathodes are releasably clamped against movement in directions transverse to cathode advancement.

Method of electrochemical machining bladed rotors

An electrically conductive arbor indexer shaft is coupled to an indexing D.C. motor by an insulator connector and the indexer shaft in an indexed position is tightly gripped by a resilient electrically conductive clamp connected to an electrically conductive support to which a buss is engaged for supplying electrical current to the arbor via the indexer shaft, clamp and support. During the ECM process, a workpart on the arbor is made an anode by current passing through the arbor indexer shaft, clamp, support and buss with the resilient clamp insuring sufficient electrical coupling of the arbor indexer shaft to the other upstream current carrying components.

Electrical continuity clamp for ECM machine

A six axis ECM machine is provided for electrochemically machining the airfoil blades of an integrally bladed rotor of a gas turbine engine. The cathodes of the machine each move along two different sets of axes, a right X-axis and Y-axis and left X-axis and Y-axis, relative to a workpart machining position in the electrolyte chamber while the rotor is moved vertically along a Z-axis. The rotor is indexable about a sixth horizontal axis to present individual airfoil blades for machining at the workpart machining position. The rotor is fixtured on the Z-axis slide with its lateral center plane at an angle relative to the cathodes at the workpart machining position and the cathodes have recessed pockets to receive airfoil blades immediately adjacent the individual blade being machined as the individual blade is positioned at the workpart machining position. These features of the machine provide full access of the cathodes to the blade to ECM the sides, leading and trailing edges, fillet radii and platform of the blade.

Multi-axis ECM machine useful for machining airfoils of rotors

A machine for electrochemically machining oversize airfoil blades of an integral bladed gas turbine engine rotor includes a yoke assembly on which the rotor is fixtured and which is pivotable to place the lateral center plane of the rotor at an angle or skew relative to the center plane of the machine and opposed cathodes in an electrolyte chamber at a workpart machining position in the chamber. The cathodes have pockets to receive airfoil blades adjacent the individual blade to be machined without contact with the adjacent blades as the cathodes and workpart are moved relative to the workpart machining position during workpart positioning in the chamber and also during advancement of the cathodes from a cathode start machining position toward the workpart during machining. The yoke assembly includes a pivot pin and locking mechanism for releasably locking the angular position of the yoke assembly. The angular relation of the center planes as well as pockets in the cathodes permit full accessing of the individual airfoil blade to be machined by movement of the cathodes in multiple directions.

ECM machine with skewed workpart and pocketed cathodes

An integral bladed rotor for a gas turbine engine is fixtured on an incrementally indexed arbor and enclosed by a shroud except for a portion of the rotor to be inserted into an electrolyte chamber for machining by opposed cathodes at a workpart machining position. The shroud and electrolyte chamber are in sealed relation when the portion of rotor is inserted for machining, and the shroud and electrolyte chamber include cooperative locating features to precisely position the rotor portion at the workpart machining position in the chamber. The shroud remains on the arbor during incremental indexing of the latter and is itself retained against substantial indexing movement while the rotor is indexed.

Growing community of inventors

Monroe, CT, United States of America

Edmund R Hinman