This narrow-hole electric discharge machine (100), which performs electric discharge machining by relatively moving a narrow-hole electrode (28) attached to a main spindle (114) and a workpiece (130) attached to a table (118), comprises: a positioning guide (16) which is attached to a guide arm (142) below the main spindle, through which the narrow-hole electrode is inserted such that a lower portion of the narrow-hole electrode is movable in the direction of an axis line (CL0), and which supports the narrow-hole electrode; and a power feeder (10) which is provided at a predetermined position directly above the positioning guide of the guide arm, comes into direct contact with the narrow-hole electrode movable in the axis line direction and feeds power to the narrow-hole electrode, wherein the distance from a power feed position to the tip of the positioning guide is constant regardless of the length of the narrow-hole electrode.

This narrow-hole electric discharge machine (100), which performs electric discharge machining by relatively moving a narrow-hole electrode (28) attached to a main spindle (114) and a workpiece (130) attached to a table (118), comprises: a positioning guide (16) which is attached to a guide arm (142) below the main spindle, through which the narrow-hole electrode is inserted such that a lower portion of the narrow-hole electrode is movable in the direction of an axis line (CL0), and which supports the narrow-hole electrode; and a power feeder (10) which is provided at a predetermined position directly above the positioning guide of the guide arm, comes into direct contact with the narrow-hole electrode movable in the axis line direction and feeds power to the narrow-hole electrode, wherein the distance from a power feed position to the tip of the positioning guide is constant regardless of the length of the narrow-hole electrode.

Modular tubing apparatuses for use in a shell-and-tube heat exchanger are described. Multiple apparatuses may be connected in series to form a high density, small tube diameter, long length tube apparatus assembly. Casting molds for forming modular tubing apparatuses are likewise described, including methods for casting and electrochemically machining such apparatuses.

Modular tubing apparatuses for use in a shell-and-tube heat exchanger are described. Multiple apparatuses may be connected in series to form a high density, small tube diameter, long length tube apparatus assembly. Casting molds for forming modular tubing apparatuses are likewise described, including methods for casting and electrochemically machining such apparatuses.

An electrical machining method comprises machining a workpiece by an electrical machining device comprising an electrode; increasing a feedrate of the electrode at a first acceleration if a discharge current passing through the electrode and the workpiece is lower than a discharge current reference; and decreasing the feedrate of the electrode at a second acceleration if the discharge current is higher than the discharge current reference, wherein the second acceleration has an absolute value higher than that of the first acceleration.

A wire electrical discharge machine includes a first voltage applying circuit, a second voltage applying circuit, and a switch controller. The first voltage applying circuit includes a first DC power source for applying a positive polarity voltage across an electrode gap, and a first switch for on/off-switching of application of the positive polarity voltage. The second voltage applying circuit includes a second DC power source for applying a reverse polarity voltage to the electrode gap, and a second switch for on/off-switching of application of the reverse polarity voltage. The switch controller controls the first switch and the second switch so that the first switch and the second switch are not turned on simultaneously. The first DC power source and the second DC power source are set up so that the absolute value of the reverse polarity voltage is lower than the absolute value of the positive polarity voltage.

A wire electrical discharge machine includes a first voltage applying circuit, a second voltage applying circuit, and a switch controller. The first voltage applying circuit includes a first DC power source for applying a positive polarity voltage across an electrode gap, and a first switch for on/off-switching of application of the positive polarity voltage. The second voltage applying circuit includes a second DC power source for applying a reverse polarity voltage to the electrode gap, and a second switch for on/off-switching of application of the reverse polarity voltage. The switch controller controls the first switch and the second switch so that the first switch and the second switch are not turned on simultaneously. The first DC power source and the second DC power source are set up so that the absolute value of the reverse polarity voltage is lower than the absolute value of the positive polarity voltage.

This fine hole electrical discharge machine applies voltage between a fine hole machining electrode and a workpiece to cause discharge, and machines a fine hole in the workpiece by using energy of the discharge. The fine hole electrical discharge machine comprises: a bendable guide tube having a hollow portion through which the electrode is inserted; and a tube holder that supports the leading end of the guide tube and allows the leading end of the guide tube to be inclined at a desired angle. Thus, even when the workpiece has a complicated shape, like a blisk, having a large number of turbine blades arranged in the circumferential direction, a fine hole can be machined by accurately positioning the electrode so as to orient the electrode toward a target machining point on a surface of the workpiece without involving interference with the workpiece.

A spark erosion tool includes an electrode arranged on a tool longitudinal axis and an electrode holder aligned along and arranged on the axis and connected to the electrode. The electrode holder includes a moving device for moving the electrode relative to the electrode holder and includes a press for applying pressure transversely to the axis in the area of an imaginary hose extending in the axis. The electrode holder has a cross section corresponding essentially to the electrode. An electrode for a spark erosion tool with a cylinder surface or a spherical surface includes a groove connected to a bore. A deflecting bore can be produced in a drill string part using the spark erosion tool. The deflecting bore is curved and connects two straight flushing bores.

The present invention is an electrochemical machining tool equipped with a tool body that comprises: an electrode that extends along an axial line and inside which a flow channel through which an electrolytic solution flows towards the tip end is formed; an insulating layer covering the outer circumferential surface of the electrode so as to expose the tip end face of the electrode; and a flow channel-partitioning part for partitioning the flow channel into a first flow channel containing the axial line and a second flow channel positioned on the outer circumferential side of the first flow channel. The electrochemical machining tool has a configuration in which a fluid outflow section for directing electrolytic solution, which is flowing through the second flow channel, outward in the radial direction of the tool body is formed on a portion of the circumference of the tool body.