Abstract: A work tank for machine tools for receiving the machining fluid comprising a fixed part and a movable part which retracts to move the tank away from the work area when it is necessary to remove a workpiece.

Abstract: A wire cutting electroerosion machine with upper and lower machining heads on cross slide systems for taper machining. The upper and lower machining heads spray a dielectric liquid at the machining zone. A reservoir and filter elements are used to recycle the liquid and resupply the liquid to the machining zone. An enclosed enclosure means is used to reduce temperature variations during machining by enabling dissipation of the heat given off and to facilitate uniform temperature distribution throughout the equipment by achieving thermal equilibrium.

Abstract: At least one machining parameter of an electrode-wire EDM machine, cutting according to a predetermined trajectory, is varied when the electrode-wire reaches the apex of an angle or approaches an arc. The strategy consists of the following stages:1) calculation of the locations along the trajectory or path at which these variations must be started;2) stopping of relative electrode-wire movement and the work-piece, when the wire reaches one of these points;3) gradual and stepped variations of the parameter up to a final designated value or until a predetermined number of steps have been performed;4) resumption of wire-part relative movement, with the new parameter value over a computer predetermined distance, and5) variation of the parameter in the opposite direction so as to return it to its initial value.The step durations are slaved to changes of a factor giving an image of the conditions existing in the machining slot, around a predetermined threshold.

Abstract: An electric discharge machine with a turning or touch-up of the electrode uses an auxiliary tool for cutting or chiseling within an auxiliary tool holder which is mounted in the tank and includes a reference sphere for determining the electrode's shape. The auxiliary tool can include an assembly of several mechanical tools mounted symmetrically.

Abstract: An EDM device for machining by electro-erosion a three-dimensional cavity by compensating for tool-electrode wear, which device includes a mechanism for rotating a tool electrode whose diameter is small in comparison to the dimensions of the cavity being eroded, a numerical control unit of known type, which controls relative three-dimensional movement between the tool electrode and the workpiece, apparatus for controlling volumetric wear rate, and computational apparatus equipped for storing the volumic shape of the cavity to be eroded in the form of virtual fine parallel layers superimposed on one another, for simulating a tool path so that the tool tip sweeps groove by groove across said successive layers, and for transmitting a corresponding signal to the three-dimensional control unit, characterized by a simulator that is programmed to calculate prior to machining the longitudinal wear of the rotating tool or a value intended for additional axial feed of the tool electrode and continuously compensating fo

Abstract: The injection device for machining liquid comprises a nozzle (9) sliding in a mobile element (7) which itself slides inside a housing (1) fixed to a machining head, these three elements forming an injection chamber (2) with the base of this head. The nozzle (9) and the mobile element (7) are profiled in such a way as to delimit a pressure chamber (30) along one of the sides (31) of a shoulder (11) built on the periphery of the nozzle (9), as well as a second chamber (20) along the opposite side of this shoulder (11). The nozzle (9) has openings (28) linking this pressure chamber (30) to the injection chamber (2). The mobile element (7) has openings (10) linking the chamber (20) with the atmospheric pressure. The shoulder (11) is sized so that the pressure created in the chamber (30) at least partly counterbalances the pressure created in the injection chamber (2) and acts on the nozzle (9) in the opposite direction.

Abstract: Device and process to control at least one machining parameter of an electrode-wire EDM machine according to a protection strategy, in particular to avoid short-circuits, or to improve machining conditions so as to obviate the risk of electrode-wire breakage.

Abstract: A machining head carries at its end a sensor comprising a pressure-sensitive element (4) mounted on the parts (1, 2) holding the injector jet for the machining fluid, as well as the buffering pieces (5, 6, 12) forming a shield. The element (4) is an insulating and watertight tube, arranged to form a ring in the space left between the coaxial, truncated conical surfaces of the parts (1) and (2). It contains conducting parts which come into contact with one another when it is deformed by the action of a pressure whose value exceeds a given threshold. This results in the closing of an electrical circuit which transmits an appropriate signal to the controls of the EDM machine in order to interrupt the relative movement of the head. The device enables any shock or abnormal stress acting on the end of the machining head to be detected. By means of an O-ring seal (7) acting as a hinge, the part (1) and the piece (12) are returned to their original positions when the stress disappears.

Abstract: At least one machining parameter of an electrode-wire EDM machine, cutting according to a predetermined trajectory, is varied when the electrode-wire reaches the apex of an angle or approaches an arc. The process consists of the following stages:1) calculation of the locations along the trajectory or path at which these variations must be started;2) stopping of relative electrode-wire movement and the work-piece, when the wire reaches one of these points;3) gradual and stepped variations of the parameter up to a final designated value or until a predetermined number of steps have been performed, or during a given period of time;4) resumption of wire-part relative movement, with the new parameter value over a computed predetermined distance, and5) variation of the parameter in the opposite direction so as to return it to its initial value.The durations of the steps are predetermined or correspond to cutting of predetermined lengths along the path.

Abstract: An apparatus and method for continuously supplying and recycling machining liquid in an EDM device employ a filter between a liquid reservoir and a machining location at which the liquid is used. In one embodiment of the invention a buffer reservoir is provided between the filter and the machining location, while in another embodiment a second filter is connected in parallel with the first-mentioned filter. In either case, an assured alternative supply of filtered liquid is provided while the filter is repeatedly stopped and started in response to one or more operating parameters representing a degree of filter clogging. The stopping of the partially-clogged filter unexpectedly permits self-regeneration of the filter without the need for dismounting or backflushing for cleaning; even though cleaning is not performed, the repeated stopping by itself extends the useful life of the filter.

Abstract: An EDM machine in combination with a wire sectioning device. The wire sectioning device has two rotating members consisting of a rotating member 2 having an anvil 16 and a member 3 rotating in the opposite direction. The rotating member 3 has four cutting blades made of a tough material such as tungsten carbide or tungsten nitride. At least one of the anvil and the tool possesses a low moment of inertia to improve the longevity of the sectioning means.

Abstract: An EDM machine with a travelling wire electrode having a device for straightening and rethreading the wire electrode. The device has a pivotally rotating arm that has a clamp to grasp the free end of the wire after accidental breakage. The clamp applies a tightening stress (optionally the wire is being heated), the wire portion to be discarded is wound on a capstan (configured with circumferential grooves) associated with the clamp on the arm, a wire cutter severs the wire above the capstan, and finally the wire is rethreaded.

Abstract: Machine for cutting by electrical discharge machining includes an electrode wire tensioned between and running betwee two guide heads each of which is mounted on an arm, one at least of the arms passing through a hole in one of the walls of a tank. The tank can move with respect to the arm and contains a machining liquid. A sealing plate 1 masks the hole in the tank and is linked by at least one seal 4 to the arm 5 through the wall. The wall 2 of the tank through which the arm passes slides along this plate. To prevent the forces due to friction and pressure arising between the plate 1 and the wall 2 and between the seal 4 and the arm 5 and acting asymmetrically on the arm through the wall being transmitted to the arm 5 and causing its deflection, a sheath 6 is mounted between the seal 4 and the arm 5 and encloses this arm without coming into contact with it.

Abstract: A device permits fastening a tool (preferably an EDM tool) to a machining head in at least two different orientations. The tool is mounted on a tool holder, and a pair of portions alternately fix the holder to the head in two different orientations, for example, one in which the tool is positioned for machining operations, and another in which it is positioned for touching up. In a first embodiment the portions are formed as two studs provided on the holder each engageable with the machining head. The studs are positioned with respect to the tool so that engagement with the machining head presents the tool in the two different orientations. In a second embodiment one of the portions is formed on a first tool holder which carries the tool thereon, while the other portion is formed on a second holder mountable to the machining head, the first holder being being mountable either to the machining head directly or to the second holder.

Abstract: A device for machining by electroerosion has a tool electrode driven in a rotary motion controlled by a servomotor and showing the shape of a solid of revolution around its axis of rotation. A measuring circuit continuously evaluates the degree of contamination of the machining dielectric liquid in relation to a reference value. The measurement is made by a transducer for the instantaneous voltage U.sub.i of each spark and by comparing it to a predetermined value U.sub.b, thus determining the proportion of so-called low-level sparks for which U.sub.i .ltoreq.U.sub.b, a signal being delivered when this proportion surpasses a predetermined threshold, or by a current transductor working during the waiting time preceding the striking of each spark, a signal being delivered when a predetermined current threshold is attained. A servo circuit modulates the rotation speed of the tool electrode as a function of this signal. The detector makes it possible to detect and remedy the appearance of ejected sparks.

Abstract: A machine which uses electroerosion with an electrode piece by means of a stretched electrode wire unwound between two wire guides with at least one device with crossed movements to fabricate other pieces, these wire guides are equipped to displace in a parallel plane to that of the trajectory and to cut off in this way by inclining the wire to a predetermined angle in relation to a neutral perpendicular axis to this plane and to make it pivot on itself around a mobile axis parallel to this neutral axis passing by this guide and displacing itself with it. It presents also an equipped device in order to subjugate the rotation of the guide wire to displacements of the device to crossed movements. At least one of the wire guides is in preference to an open guide open to a gap.

Abstract: Device placed at the outlet of a machining zone and having an outflow gauge equipped with two barrels in which a metal wire passes, an electrical current running through the wire which travels under tension between two guides, a pumping installation injecting a machining fluid under pressure through an opening of this guage, an element mounted at another opening of the gauge to measure the outflow of this fluid between wire and barrel, a transducer converting this measurement into an electrical variable, and a comparator suitable for sending a signal to a control unit when this measurement reaches or surpasses a reference value. The control unit is arranged for controlling a pulse generator to change at least one machining parameter in such a way as to bring the measurement of the outflow to or to below the reference value. This device is useful for monitoring the variation in the cross-section of the wire and preventing its breaking.

Abstract: An electro-erosion machine for automatic completion of a cutout according to a closed trajectory or whose ends reach the edges of a part to be machined, or for completing a hollowing by means of piercing the part to be machined all the way through, as well as separating, at a certain predetermined machining moment, a clipping still retained by a narrow bridge of material, said machine being fitted with a numerical control device and at least one machining head, as well as with an auxiliary device, designed to break the bridge which retains the clipping, said clipping being of any shape, and to drop or eject said clipping, the separating being accomplished either by percussion or by exerting a pressure on it, or by shearing the bridge or exerting a torsion-tearing couple on it, or by submitting it to a thermal effect or by localized radiation of the bridge. It can also include an attachment for receiving and automatically evacuating the clipping expelled in this manner.

Abstract: The device has a case (1) which has a wire guide (2) and a chamber (4) filled with machining liquid which is brought there under pressure by a pipe (7). A nozzle (5) in the shape of a truncated cone fits in the case and closes the chamber (4) in its normal working position by supporting its periphery on the flange (6) provided around the case (1), under the action of the pressure exerted by the dielectric liquid and if necessary by a return spring (8). The thrust exerted on the nozzle by an obstacle (10) during a lateral collision tilts the nozzle without damaging it and it causes at L an escape of liquid which causes the pressure to drop in the chamber (4). A transducer (13) signals the drop in pressure following the collision to the operator and/or to a control system of the erosion machine.

Abstract: A method and apparatus for automatically rethreading the electrode wire of a traveling wire EDM apparatus through a pair of close tolerance wire support and guide members, one disposed on one side of a workpiece and the other on the other side of the workpiece, and for threading the end of the wire through a starting aperture in the workpiece. Prior to threading or rethreading the wire, the wire is heated in a heating zone while a pull is exerted on the wire such as to elongate the heated portion of the wire to reduce its diameter. After cutting off the wire at the beginning of its reduced diameter portion, the reduced diameter portion of the wire is threaded through the wire guide members and the aperture in the workpiece. The threading of the wire is effected by a feed mechanism disposed upstream of the first wire guide member which preferably is the same mechanism as the brake mechanism effecting a pull on the wire during normal operation of the EDM apparatus.