Abstract: A wire tension controlling method in a wire cut electric discharge machine, capable of preventing occurrence of an excessive variation in a wire tension which may be caused by an abnormal operation of an electromagnetic powder brake upon start and release of application of the wire tension, and upon change of same.

Abstract: A wire-extension end detector having high operational reliability is provided for use with a wire-cut electric discharge machine. As a wire comes between a wire drive roller and a pinch roller during a wire extension, it is conveyed by rotation of the rollers. As the wire travels, a disc (4c) integral with a tension brake roller driven by the running wire is rotated. A signal processing circuit (24) receives and delivers a pulse train output from a photoelectric switch (5) in accordance with a black-and-white code pattern on a rotating disc coupled thereto, and generates an H-level output indicative of the end of wire extension. If the wire extension fails, an H-level output from the signal process circuit is not output and a wire extension is carried out again.

Abstract: A wire drive apparatus in a wire-cut electric discharge machine, which is capable of effecting wire extension smoothly even by a single drive source, and of preventing wear of belts and variation in wire feed speed. Upon wire extension, a lower belt section (3) pivotally supported through links (33, 34, 36, L) is moved toward an upper belt section (2) with actuation of air cylinders (10, 12), so that belts (21, 31) of these belt sections are brought in urged contact with each other, and a wire is delivered for the wire extension by the belts which are rotated, a wire drive roller (4). After completion of the wire extension, the lower belt section is moved to a position at which it is separated from the wire, and at this time the upper belt section is also separated from the wire, and power transmission from the wire drive roller to the lower belt section is disconnected.

Abstract: A wire-cut electrical discharge machine having a device for preventing an accident due to an electrical shock, wherein a guide roller (34a) disposed just before a collection box (38) for collecting a used electrode wire (30) passed through an electrospark machining area (36) is attached to a base plate (56) made of a conductive material, the base plate being fixed to a machine body (26) through an insulating plate (58), and a current leaking to the base plate caused by a disturbance of the running of the electrode wire is led to a safety circuit (50) through a lead wire (52), and a current leakage signal is output whereby an electric power supply of a electric power source (51) is rapidly stopped to prevent an accident due to an electric shock.

Abstract: A wire cut electrodischarge machine tool, wherein when the electrode wire breaks during electrodischarge machining, the wire disconnected end is cut and repaired at a repair position far from the electrodischarge machining region by a cutter means, following movement of the wire end is prevented when the cutter is retracted, the electrode wire is automatically laid between upper and lower heads having built-in wire guides, and thus electrodischarge machining on the workpiece is automatically prepared for.

Abstract: A working fluid supplying apparatus of an electric discharge machine comprises a main pipe and a branching pipe for connecting a pump for increasing a working fluid in pressure and delivering the thus pressurized working fluid with a nozzle for injecting the pressurized working fluid, these pipes being connected in parallel to each other, and respectively provided therein with a servo valve for flow rate control, which has its valve opening in accordance with a command indicative of a target flow rate and supplied from a controller, and an on-off valve which is rendered open upon a predetermined servo valve opening being reached, whereby non-linearity between the servo valve opening and the flow rate of the working fluid flowing through the main pipe provided with the servo valve is compensated for by the working fluid supplied through the branching pipe provided with the on-off valve so as to achieve a liner control of the working fluid flow rate even when the target flow rate increases beyond a value corres

Abstract: A wire cut electrical discharge machine (10) has two machining fluid supply systems respectively for supplying machining fluid is having different qualities to the machining section (14) thereof, namely, a rough-machining fluid supply system (20) and a finish-machining fluid supply system (60). The rough-machining fluid supply system (20) has a first machining fluid quality regulating circuit comprising a first machining fluid tank (26) having a filtering device (3) for filtering powdery chips, a specific resistance detector (34), a cooler or heater (42, 44), an ion exchange device (52) and pumps (40, 58), and the finish-machining fluid supply system (60) has a second machining fluid quality regulating circuit comprising a second machining fluid tank (66), a specific resistance detector (74), an ion exchange device (92), a cooler or heater (42, 44) and pumps (40, 98).

Abstract: A three-point support guide (1) for a wire electrode 100 in a wire electric discharge machine, which includes first and second guide members (20, 60) each formed of a small, thin diamond. The first guide member (20), is supported in the body (10) of the guide (1) so as to face a wire electrode bore (12). A movable member (40) is provided which is movable toward and away from the first guide member (20). The second guide member (60) is embedded in the movable member (40) so as to face the first guide member (20). The second guide member (60), in conjunction with the first guide member (20), provides three-point support of the wire electrode (100).

Abstract: An automatic wire connecting apparatus of a wire cut electric discharge machine performs automatic connection of a wire electrode smoothly and reliably. A wire processing unit (90) integrally rotatably coupled to a rotating shaft (61) of a pneumatic motor (60) has a nozzle forming portion (12) which defines a slit (S) that allows a wire electrode (W) to pass therethrough when it is opened, and which defines a nozzle hole (125) capable of fitting with an upper wire guide (12) when it is closed, and is selectively positioned at a wire insertion position or an escape position by a rotary stopper (150). When the wire electrode is broken, the wire processing unit is rotated from the escape position to the wire insertion position by a motor, and thereafter, the nozzle hole forming portion is closed, thereby holding the wire electrode guided through the slit during a rotating operation in the nozzle hole.

Abstract: A wire cut electric discharge machine for electric discharge machining a work (W) held on a work table (24). A wire electrode (14) supplied by a wire supplying device (12) is passed between upper and lower heads (22, 26) under tension through an electric discharge machining region where the work (W) is subjected to electric discharge machining.

Abstract: In a wire cut electric discharge machine, an apparatus is provided, which is capable of detecting completion of wire setting with a simple construction when a wire electrode (W) is automatically extended. Electric power is supplied to the wire electrode (W) from an electric power supplying section (43) through a contact (32) during automatic wire setting. When the wire electrode (W) is fed and brought into contact with an iron plate (44) disposed at a side at which the wire electrode (W) is taken out, an electric potential at the iron plate (44) of the electric power supplied section increases, to thereby detect completion of wire setting.

Abstract: A wire cut electric discharge machine (10) is equipped with a work table including a horizontal slide table (20) mounted on a metallic bed (14) of the wire cut electric discharge machine (10), and a work rest (22) fixed to the upper surface of the horizontal slide table (20). The horizontal slide table (20) and the work rest (22) are formed of an electro-conductive ceramic material to connect the work table directly electrically to the grounded metallic bed (14) so that the work table is held at ground potential without increasing reactance (L).

Abstract: The electric discharge machining apparatus of the wire-cutting type comprises a wire-treating unit (48) movable in the horizonal direction relative to an upper wire guide member (12) between the upper wire guide member and a work table (10) to traverse a wire electrode (W) extending downward from a wire passage (13) of the upper wire guide member. The wire-treating unit has a base block (55) and a movable block (56) that can approach to and separate from the base block to define a slit (60) and a nozzle hole (61) that can be opened and closed between the two blocks. The slit extends in the horizontal moving direction of the wire-treating unit to receive the wire electrode therein. The nozzle hole can be connected to the lower end of the wire passage of the upper wire guide member, and the nozzle hole is constructed so that a spray liquid supplied into the wire passage of the upper wire guide member can be injected into a wire passage (15) of a lower wire guide member (14).

Abstract: A wire feed mechanism of a wire electric discharge machine, which rewinds a wire electrode (P), that is broken during electric discharge machining, by a wire electrode feed reel (1) to a state convenient for connection of the electrode. The mechanism has a clutch (3) having an output shaft (5) coupled to the wire electrode feed reel and creating a coupling torque between input and output members (3a, 3b) in a manner changing in accordance with a feed voltage, and a geared motor (M) coupled to an input shaft (6) of the clutch. When the wire electrode is broken, the feed reel is coupled to the geared motor, that is stopped, through the clutch which receives a high voltage and the input and output members of which are firmly engaged with each other, to be prevented from idling. The thus stopped feed reel is then driven by the geared motor at a predetermined torque and a low speed through the clutch which is supplied with a decreased voltage and loosely engaged, to rewind the wire electrode.

Abstract: A spindle head unit having a bell crank lever (24) mounted pivotally on a spindle head (10) of a machining center to depress a drawbar (18) inserted through a spindle (14) mounted on the spindle head (10). One of arms of the bell crank lever (24) is located so as to be capable of being engaged with a guide cam (28) and a depressing end (24a) in the shape of a spherical protrusion which is not connected mechanically to an upper end (18a) of the drawbar (18) is formed in a free end of the other arm of the bell crank lever (24). The bell crank lever (24) is urged continuously by a spring means (32) so that the former arm is urged toward the guide cam (28).

Abstract: A wire electrode electrical discharge machine includes an initial hole forming device mounted on a frame unit attached to the vertical slider of the electrical discharge machine; the initial hole forming head is vertically movable on the frame unit and has a rotary chuck for holding a hollow bar electrode; electrical switches on the frame unit generate signals upon the detection of the initial hole forming head being position at an initial hole forming position and at a resting position in its vertical movement on the frame unit and lateral movement of the upper wire guiding unit toward the initial hole forming head is inhibited while the initial hole forming head is located at the initial hole forming position.

Abstract: A wire-cut electrical discharge machine for machining a workpiece (W) through wire-cut electrical discharge machining by employment of an electrode wire (60) which runs from one to the other of upper and lower guide assemblies each having a cooling liquid supply passage (62) and a main passage (64) communicating with the cooling liquid supply passage (62). At least either the upper guide assembly or the lower assembly is provided with a restrictor valve (68) provided in a branch passage (66) branched from the main passage (64) and capable of varying the effective sectional area of the liquid passage of its own according to the pressure of the cooling liquid supplied from the cooling liquid supply passage (62) into the branch passage. The cooling liquid that passed the restrictor valve (68) is introduced into the vicinity of the feeder pin (42) of the guide assembly to cool the feeder pin (42) and the electrode wire running in the vicinity of the feeder pin (42).

Abstract: An electrical discharge boring machine including: a main unit (12) which is moved vertically relative to a workpiece (W); a rotary chuck (14) attached to the lower part of the main unit (12) for holding a hollow bar electrode (16); a guide (36) for slidably guiding the hollow bar electrode (16) near the workpiece (W); a nozzle unit (40) provided on the lower part of the guide for supplying a machining liquid; a rotary joint (28) for introducing the machining liquid into the hollow bar electrode; and a connection (34) for supplying electric power for electrical discharge machining to the hollow bar electrode.

Abstract: A wire guide consisting of a V-groove-type guide, a device for supplying machining liquid, and a die-type wire guide removably attached at the lower surface of the V-groove-type guide causes increased machining accuracy while used in both non-taper machining and taper machining modes. The increased accuracy is achieved after the wire passes through the V-groove-type guide by using the die-type wire guide to return the wire to a straight path to improve the linearity of the wire and, accordingly, improve machining accuracy.

Abstract: An automatic tool changer of a machine tool comprises a spindle head (4) rotatably carrying a spindle (2), and a tool magazine (40) having a plurality of tools (42). A pair of gears (46, 48), one on the spindle and the other on the magazine, are provided to drive the magazine to index it by means of the spindle drive motor (6). The two gears (46, 48) are engaged upon the tool changing operation and disengaged upon the machining operation. The Gear engaging and disengaging are effected by the relative axial movement of the spindle head (4) and an associated slider (30) carrying the magazine (40).