Electrical discharge process and apparatus for machining elongated workpieces

An apparatus configured to perform a die sinking electrical discharge machining process, particularly for machining workpieces, particularly elongated workpiece, wherein the elongated workpiece has a first and a second end, a longitudinal axis, the apparatus comprising:

• a tank configured to contain a dielectric fluid,
• a support frame comprising a base plate and
• a machining head unit, equipped with an electrode that is configured to perform the electrical discharge machining process on the elongated workpiece,
• wherein
• the apparatus comprises:
• at least one adjustable support, upon which the elongated workpiece to be machined can be placed and rotated,
• wherein the height of the adjustable support is adjustable, so as to adjust the position of the elongated workpiece with respect to a first axis, perpendicular with respect to the base plate, and
• in that the apparatus further comprises a rotating member adapted to grip one of the ends of the elongated workpiece to be machined and rotate it around its main axis.

A method for machining a monolithic shaft-impeller rotor and the like by Die Sinking electrical discharge machining process, wherein the monolithic shaft-impeller rotor has a first and a second end, a main axis and at least one impeller, and wherein an apparatus comprises a machining head unit, equipped with an electrode that is configured to perform the electrical dis-charge machining process on the monolithic shaft-impeller rotor,

• wherein
• the apparatus comprises least one adjustable support, upon which the monolithic shaft-impeller rotor to be machined can be placed and rotated, wherein the height of the adjustable support is adjustable, so as to adjust the position of the monolithic shaft-impeller rotor with respect to a first axis, perpendicular with respect to the base plate, and a rotating member adapted to grip one of the ends of the monolithic shaft-impeller rotor to be machined and rotate it around its main axis, wherein said rotating member comprises a collar, having a housing, in which one of the first or the second end of the monolithic shaft-impeller rotor to be machined can be inserted, and
• in that the method comprises the following steps:
• A. arranging the monolithic shaft-impeller rotor on the bearings of the at least one adjustable support;
• B. inserting one of the ends of the monolithic shaft-impeller rotor in the housing of the collar;
• C. checking the position of the monolithic shaft-impeller rotor, so that the rotating table rotates the monolithic shaft-impeller rotor over its rotation main axis;
• and,
• D. carrying out the Die Sinking electrical discharge machining process by means of the electrode.