An EDT apparatus 1 is disclosed, comprising a dielectric fluid return system for use with an EDT machine of the type in which the workpiece is not submersed in dielectric fluid. The return system comprises a first collector 19 for catching spills from a dielectric bath 9 associated with a set of electrodes 10 which apply electrical pulses to the workpiece through the dielectric fluid in the bath. Also, a separate, second collector 21 is positioned substantially beneath the workpiece and arranged both to receive fluid from the first collector 19 and to catch fluid that drips from the workpiece itself, the second collector being connected to a pump 13 which returns the fluid from the second collector to the dielectric bath.

An EDT apparatus 1 is disclosed, comprising a dielectric fluid return system for use with an EDT machine of the type in which the workpiece is not submersed in dielectric fluid. The return system comprises a first collector 19 for catching spills from a dielectric bath 9 associated with a set of electrodes 10 which apply electrical pulses to the workpiece through the dielectric fluid in the bath. Also, a separate, second collector 21 is positioned substantially beneath the workpiece and arranged both to receive fluid from the first collector 19 and to catch fluid that drips from the workpiece itself, the second collector being connected to a pump 13 which returns the fluid from the second collector to the dielectric bath.

In an electrical discharge machine, the top end of a vertically extending electrode is supported by an electrode holder so as to be able to be raised and lowered, the circumferential surface of the bottom end of said electrode is supported by an electrode guide that is disposed so as to be able to move vertically with respect to the electrode holder, and the position of said electrode guide is detected by a position detection unit. This electrical discharge machine is provided with a work-tank raising/lowering device. During electrical discharge machining, said work-tank raising/lowering device raises/lowers a work tank, in accordance with the electrode-guide position (Hg) detected by the position detection unit, so as to set the distance from a prescribed part of the work tank to the electrode-guide position (Hg) equal to a prescribed value (Ha).

In an electrical discharge machine, the top end of a vertically extending electrode is supported by an electrode holder so as to be able to be raised and lowered, the circumferential surface of the bottom end of said electrode is supported by an electrode guide that is disposed so as to be able to move vertically with respect to the electrode holder, and the position of said electrode guide is detected by a position detection unit. This electrical discharge machine is provided with a work-tank raising/lowering device. During electrical discharge machining, said work-tank raising/lowering device raises/lowers a work tank, in accordance with the electrode-guide position (Hg) detected by the position detection unit, so as to set the distance from a prescribed part of the work tank to the electrode-guide position (Hg) equal to a prescribed value (Ha).

A dielectric working fluid centralized management system is equipped with a dielectric working fluid adjustment apparatus for adjusting the fluid quality of a dielectric working fluid of a plurality of wire electrical discharge machines, a dielectric working fluid delivery and reception control member for controlling delivery and reception of the dielectric working fluid between a plurality of dielectric working fluid storage tanks disposed corresponding respectively to the plurality of wire electrical discharge machines, and in which the dielectric working fluid is stored, and the dielectric working fluid adjustment apparatus, and a dielectric working fluid quality controller, which receives dielectric working fluid information from the plurality of wire electrical discharge machines and controls the dielectric working fluid delivery and reception control member, or both the dielectric working fluid delivery and reception control member and the dielectric working fluid adjustment apparatus.

A dielectric working fluid centralized management system is equipped with a dielectric working fluid adjustment apparatus for adjusting the fluid quality of a dielectric working fluid of a plurality of wire electrical discharge machines, a dielectric working fluid delivery and reception control member for controlling delivery and reception of the dielectric working fluid between a plurality of dielectric working fluid storage tanks disposed corresponding respectively to the plurality of wire electrical discharge machines, and in which the dielectric working fluid is stored, and the dielectric working fluid adjustment apparatus, and a dielectric working fluid quality controller, which receives dielectric working fluid information from the plurality of wire electrical discharge machines and controls the dielectric working fluid delivery and reception control member, or both the dielectric working fluid delivery and reception control member and the dielectric working fluid adjustment apparatus.

It is an object to provide a small-hole electrical discharge machining device to discharge the machining debris efficiently and to drill a small hole by electrical discharge machining at a high speed.

It is an object to provide a small-hole electrical discharge machining device to discharge the machining debris efficiently and to drill a small hole by electrical discharge machining at a high speed.

An electrical discharge machining apparatus includes: a surface plate; a machining tank that surrounds the surface plate, retains a machining liquid, and has at least a part that serves as a substantially box-shaped vertically moveable ascent/descent machining tank, the ascent/descent machining tank having an outlet in an ascent/descent inner wall of the ascent/descent machining tank; an ascent/descent device that raises and lowers the ascent/descent machining tank; a sub-tank that receives the machining liquid that overflows from the machining tank; a slit that is provided in an end wall of the sub-tank for allowing a connection member to pass through, the connection member connecting the ascent/descent machining tank and the ascent/descent device; and a seal that is arranged in a gap between the ascent/descent machining tank and an inner wall of the sub-tank and prevents the machining liquid in the machining tank from leaking out into the sub-tank.

An electrical discharge machining apparatus includes: a surface plate; a machining tank that surrounds the surface plate, retains a machining liquid, and has at least a part that serves as a substantially box-shaped vertically moveable ascent/descent machining tank, the ascent/descent machining tank having an outlet in an ascent/descent inner wall of the ascent/descent machining tank; an ascent/descent device that raises and lowers the ascent/descent machining tank; a sub-tank that receives the machining liquid that overflows from the machining tank; a slit that is provided in an end wall of the sub-tank for allowing a connection member to pass through, the connection member connecting the ascent/descent machining tank and the ascent/descent device; and a seal that is arranged in a gap between the ascent/descent machining tank and an inner wall of the sub-tank and prevents the machining liquid in the machining tank from leaking out into the sub-tank.