Abstract:
Dipositif placé à la sortie d'une zone d'usinage et comportant une jauge à fuites (4) munie de deux canons (1,2) dans lesquels passe un fil métallique (3), parcouru par un courant électrique et défilant sous tension entre deux guides (8), une installation de pompage (9,10,11) injectant sous pression un fluide d'usinage à travers l'orifice (5) de cette jauge (4), un organe (7) monté à l'orifice (6) de la jauge (4) pour mesurer les fuites entre fil et canon de ce fluide, un transducteur (12) traduisant cette mesure en grandeur électrique, un comparateur (13) apte à envoyer un signal vers la commande numérique (15) dès que cette mesure atteint ou dépasse une valeur de référence. L'orifice (5) est muni d'un diaphragme (16). La commande (15) est agencée pour commander au générateur d'impulsions (14) de modifier au moins un paramètre d'usinage de façon à ramener la mesure des fuites en dessous de ou à la valeur de référence. Ce dispositif est utile pour suivre la variation de la section du fil (3) et éviter sa rupture.
Abstract:
Le procédé comprend la division du fil à éroder en plusieurs secteurs et la détermination du nombre de décharges produites dans chacun de ces secteurs à partir d'un instant déterminé. Ces nombres sont ensuite comparés à un ensemble de valeurs de consigne pour déterminer l'écart entre les nombres de décharges observés et les valeurs de consigne correspondantes. Dans le cas le plus simple, toutes les valeurs de consigne sont égales à la valeur moyenne du nombre de décharges par secteur. Si l'un ou plusieurs des écarts constatés dépassent des seuils prédéterminés une modification adéquate des paramètres d'usinage peut être effectuée en relation avec des écarts.
Abstract:
Spark-erosion machining method and machine implementing a machining gap, a process regulator, a numerical control system, a Nominal Trajectory. The latter describes the movement of the tool electrode relative to the part as it ought to proceed if no disturbance were to occur during the machining. Information contained in the Nominal Trajectory is used to define at least two control vectors Vg, Vp which orient, within the coordinate system XYZ, two independent regulation movements. The first, or Gap Vector Vg , defines the direction in which a first regulation movement of the axes of the machine must be performed to maintain the removal of material. The second, or Position Vector Vp , defines the direction in which a second regulation movement of the axes of the machining machine must be performed to correct a tool electrode position error. The respective amplitudes of the regulation movements are calculated in real time by the process regulator.
Abstract:
Electron discharge machining method and device whereby a work piece (2) is machined using a tool (1) along a machining front which retreats ahead of the tool under the effect of spark erosion. The work piece and the tool are separated from one another by a machining gap. A cyclic sequence of voltage pulses (Uign) is applied between the tool and the work piece in order to generate the sparks used for erosion. The tool is moved along a number of axes (3, 4, 15) relative to the work piece. The sparks used for erosion are separated from one another by pauses (TS). A parameter (TDmoy) representative of the width of the machining gap is measured (7, 10, 11 ) in real time. The method and the device are characterized in that the variations in the width of the machining gap are countered by means of a permanent control loop (5, 7, 10, 11, 16, 20, 9, 6, 5) which governs the mean machining power (Pmoy) in accordance with a continuous law which makes the pause (TS) dependent on the parameter that represents the width of the machining gap (TDmoy). Said internal loop does not cause any change in axis. By virtue of these features, an electron discharge machining method and device are obtained that have very rapid, almost instant, control, thus eliminating the defects caused by mechanical inertia.
Abstract:
Method for controlling an electric discharge machining process, wherein a tool electrode is moved relatively to a workpiece with a working gap distance, wherein the process comprises a current and at least one previous erosion cycle, the current and the previous erosion cycle each being divided into predetermined time intervals each comprising at least one discharge pulse, wherein similar working gap conditions are present within a time interval of the previous erosion cycle and of the current erosion cycle, and wherein subsequent erosion cycles are separated by a process pause cycle, the method comprising the steps of: measuring a value of a significant process parameter within a time interval of the previous erosion cycle, the significant process parameter being indicative of the working gap distance; determining a deviation value based on the measured value and a desired value of the significant process parameter of the time interval of the previous erosion cycle; and in the current erosion cycle, controlling the relative movement of the tool electrode in the erosion direction within the time interval of the current erosion cycle based on the deviation value determined for the time interval of the previous erosion cycle and at least one instantaneous process parameter being indicative of the instantaneous process conditions.
Abstract:
The electrical discharge machine comprises a tool (17) intended to machine a workpiece (15) positioned in a work tank (12) containing a machining fluid (16). A regulating device (29) for regulating the level of machining fluid in the work tank is mounted in an outlet pipe (26) connecting the work tank to a reservoir (24). It comprises a deformable element (31), such as an inflatable balloon, connected to a source of pressurized fluid. The dimensions of this deformable element (31) are controlled by a control unit (33) acting on the pressurized fluid. By virtue of the invention there is obtained reliable control over the level of machining fluid, insensitivity to soiling, and high flexibility of installation.
Abstract:
Hybrid-Kühlung für eine Leiterplatteneinheit für eine Werkzeugmaschine, mit: wenigstens einem Kühlkörper (4) der derart ausgebildet ist, dass er Wärme von oberflächenmontierbaren Leistungsbauelementen (1) auf der Leiterplatteneinheit aufnehmen kann, wobei der Kühlkörper einen Bereich zur Flüssigkeitskühlung und einen Bereich zur Luftkühlung aufweist, so dass er Wärme sowohl an ein gasförmiges als auch ein flüssiges Kühlmedium abgeben kann.
Abstract:
The invention relates to a method and generator for generating a time sequence of EDM pulses having a predefined ignition voltage for electrical discharge machining. An AC voltage is generated from a DC voltage, furnished by a bipolar current source (8-17). The AC voltage is applied to an isolating transformer (27) disposed between the bipolar current source (8-17) and the spark gap (EL, WS). A first pulse capacitor (47, 48, 61, 62) is charged by the bipolar current source (8-17) to a voltage corresponding to the ignition voltage. The ignition voltage provided by the isolating transformer (27) is switched with a selected polarity to the spark gap (EL, WS).