Methods of forming an annular undercut
OwnerClifford A. Moberginventor
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Abstract
A method is provided for electrical discharge machining (EDM) a workpiece to include an annular undercut having a curved cross-sectional shape. The annular undercut is useful, for example, in making devices such as the tooling for plastic injection-molding of plastic parts including crab's claw seals. According to embodiments of the method, a workpiece is rotated about a central workpiece axis. An energized EDM electrode is moved in a plane containing the central axis and about an electrode axis generally perpendicular to the plane toward the rotating workpiece to provide a spark gap between the shaped electrode tip and the body. At least portions of the undercut are then formed by the EDM electrode as the workpiece is rotated. Devices made according to the forming methods are described.
Claims19
A method of electrical discharge machining (EDM) an annular undercut having a curved cross-sectional shape, the method comprising:
- providing a workpiece having a body and a central axis;
- providing an EDM electrode having a shaped tip with an outer surface corresponding to the curved cross-sectional shape of the annular undercut;
- rotating the workpiece about the central axis;
- energizing the electrode;
- moving the shaped electrode tip in a plane containing the central axis and about an electrode axis generally perpendicular to the plane toward the rotating workpiece to provide a spark gap between the shaped electrode tip and the body;
- and
- forming, by EDM, at least a portion of the annular undercut in the body during workpiece rotation.
A method of electrical discharge machining (EDM) an annular undercut in a workpiece comprising:
- providing a plurality of electrodes, each electrode having a curved tip;
- rotating the workpiece about a workpiece central axis;
- sequentially moving each electrode tip within a plane containing the central axis about an electrode axis generally perpendicular to the plane such that the tips are progressively advanced proximate the workpiece and a spark gap is formed therebetween;
- energizing each electrode when proximate the workpiece;
- and
- progressively forming the annular undercut with the energized electrode tips during workpiece rotation until the annular undercut is fully formed.
Dependencies are inferred from the claim text.