Abstract: An electro discharge machining apparatus comprises an electrode configured to machine a desired feature in a workpiece, a pulse generator configured to energize the electrode and the workpiece to opposite electrical polarities, a machining solution source configured to pass a machining solution between the electrode and the workpiece, and a servomotor configured to drive the electrode to move relative to the workpiece. The electro discharge machining apparatus further comprises at least one detection element configured to detect machining signals, and a controller. The controller controls the pulse generator and the servomotor to machine the workpiece according to a plurality of first process parameters predetermined therein and analyzes the detected machining signals to generate a first response signal to activate a plurality of second process parameters predetermined therein and different from the first process parameters to machine the workpiece. An electro discharge machining method is also presented.

Abstract: A method for making a test specimen includes machining out a chordal core from an annular forging and machining the specimen symmetrical about a chordal axis of the core. A linear cutting tool such as a wire EDM machine is used for the machining which includes at least a partially cylindrical cutting about the chordal axis with the linear cutting tool. A copper or brass tubular EDM electrode may be used. The chordal core may be machined from fat of the forging. The test specimen may have with a gauge section diameter in a range of 0.1-0.5 inches. The EDM process may include directing jets of machining fluid or dielectric in up and down along a cutting portion of an EDM wire of the EDM machine or performing the EDM process in a tank of machining fluid or dielectric with the annular forging submerged in the fluid or dielectric.

Abstract: An electro discharge machining apparatus comprises an electrode configured to machine a desired feature in a workpiece, a pulse generator configured to energize the electrode and the workpiece to opposite electrical polarities, a machining solution source configured to pass a machining solution between the electrode and the workpiece, and a servomotor configured to drive the electrode to move relative to the workpiece. The electro discharge machining apparatus further comprises at least one detection element configured to detect machining signals, and a controller. The controller controls the pulse generator and the servomotor to machine the workpiece according to a plurality of first process parameters predetermined therein and analyzes the detected machining signals to generate a first response signal to activate a plurality of second process parameters predetermined therein and different from the first process parameters to machine the workpiece. An electro discharge machining method is also presented.

Abstract: A method for making a test specimen includes machining out a chordal core from an annular forging and machining the specimen symmetrical about a chordal axis of the core. A linear cutting tool such as a wire EDM machine is used for the machining which includes at least a partially cylindrical cutting about the chordal axis with the linear cutting tool. A copper or brass tubular EDM electrode may be used. The chordal core may be machined from fat of the forging. The test specimen may have with a gauge section diameter in a range of 0.1-0.5 inches. The EDM process may include directing jets of machining fluid or dielectric in up and down along a cutting portion of an EDM wire of the EDM machine or performing the EDM process in a tank of machining fluid or dielectric with the annular forging submerged in the fluid or dielectric.

Abstract: An electrical discharge machine includes first and second coaxial electrodes and corresponding carriages. A liquid dielectric is channeled between the electrodes and a workpiece which are suitably electrically powered for machining a duplex hole in the workpiece.