Abstract: A method of electric discharge machining using a wire electrode for cutting a workpiece into a commanded shape by producing an electric discharge between the workpiece and the wire electrode and moving the wire electrode relative to the workpiece along a commanded path. The method includes steps of previously storing, in a computer memory, sets of machining conditions which differ depending upon workpiece material and thickness, reading, at the time the workpiece is to be machined, a predetermined set of the machining conditions from the memory in response to a machining condition selection instruction in a machining program and performing electric discharge machining in accordance with the set of machining conditions read from the memory.

Abstract: A method of controlling a wire-cut electric discharge machine to prevent cutting errors when cutting a corner CN which are caused by flexing of a wire electrode 1 during electric discharge cutting of a workpiece. Electric discharge is stopped when a rectilinear slot is cut to measure an amount of flexing of the wire electrode 1, and then the measured amount of flexing is used to effect an arithmetic operation to calculate a commanded speed or an interval of time in which relative movement between the wire electrode and the workpiece is arrested at the corner CN. The corner CN is cut under the control of the calculated commanded speed or interval of time in which the relative movement is arrested.

Abstract: A cutting control method for reducing cutting errors at a corner due to flexing of a wire electrode in a wire-cut electric discharge machine in which a voltage is applied between the wire electrode and a workpiece to cut the latter with electric discharge energy while moving the workpiece relatively to the wire electrode based on cutting command data for cutting the workpiece to a predetermined shape. An amount of override (K) is determined by an override arithmetic unit (103b) using data (r) on the radius of curvature of a corner angle (.theta.) data which are given as the cutting command data from a paper tape (101). A relative speed (F) is derived by a relative speed arithmetic unit (103f) from the amount of override (K) and a commanded feeding speed (F.sub.0). Motors (MX, MY) are rotated by pulse distributors (105X, 105Y) and servo circuits (SVX, SVY), respectively, based on the relative speed (F) which is lower than the commanded feeding speed (F.sub.

Abstract: Disclosed is a numerical control method for positionally controlling a movable element of a machine tool in such a manner that numerically controlled machining is performed along a projected path obtained by projecting a programmed path, lying on a predetermined plane, onto a plane of projection inclined at a predetermined angle with respect to the first-mentioned plane. The method includes the steps of entering data specifying a programmed path on the predetermined plane, subjecting the entered data to a projective transformation in accordance with entered projection angle data to generate projective transformation data specifying the projected path, and performing an interpolation on the basis of the projective transformation data to produce an output signal indicative of the results of the interpolation, and positionally controlling the movable element on the basis of the projective transformation output signal.

Abstract: A method of automatically measuring the flexure value of a wire electrode 1 in a wire-cut electric discharge machine, such that at a measurement point in the course of electric discharge machining, the electric discharge is temporarily stopped, and whether or not a wire electrode 1 and a workpiece 2 come into contact is sensed by a contact sensing device 107a. The wire electrode 1 and the workpiece 2 are moved relatively to advance or retreat in accordance with a sensed touch signal TS, and a distance .epsilon..sub.1 of movement until the contact state changes is measured. The flexure value .epsilon. is calculated from the measured movement distance .epsilon..sub.1 and the size of the discharge gap.

Abstract: There is disclosed a method of controlling a wire-cut electric discharge machine to correct cutting errors due to flexing of a wire electrode caused by electric discharge. A processing unit processes data (x.sub.1, y.sub.1, r.sub.1, x.sub.2, y.sub.2) on a corner shape which is given by a paper tape and data on an amount of flexing (D.sub.0) upon rectilinear cutting for calculating a corrected radius of curvature r.sub.1 ' of the corner, and determines the center Pc of an arc having the radius of curvature r.sub.1 ' and contacting straight lines (l.sub.1, l.sub.2) and points of contact Pt, Pt' to move the wire electrode along a straight line P.sub.1 Pt, an arc PtPt', and a straight line Pt'P.sub.3 to thereby correct the cutting error at the corner.

Abstract: In an apparatus for processing a broken wire electrode in a wire-cut electric discharge machine for cutting a workpiece into a desired contour by electric discharge machining while the workpiece is transported relative to a wire electrode on the basis of machining command data, there is disclosed an apparatus for processing a broken wire electrode including a memory (CPX, CPY) for storing the position at which the wire electrode broke, an operator's panel with jog buttons (PJX, MJX, PJY, MJY) for generating a movement command following wire breakage to retract the workpiece from the wire breakage position (Xc, Yc), motors and drive circuitry (PD, SX, SY, MX, MY) for transporting the workpiece to a predetermined position on the basis of command, and a fitted point return button (Br) on the operator's panel for generating a signal to position the workpiece at the wire breakage position after the wire electrode is rethreaded in a wire transfer system.

Abstract: A data update system in a bubble memory in which, to preserve the simultaneity of data in the event of a power failure during the updating of data in the bubble memory, initialization data is written into a specific data storage area of the bubble memory the initialization data indicates that the data in a first data storage area is invalid, and new data is subsequently written into the first data storage area from a first record to a last record successively under the control of a bubble memory controller. The initialization data is thereby erased after the new data is completely written in the first data storage area, after which the new data, written in the first data storage area, is again written into a second data storage area from the first record to the last record thereof.

Abstract: A system for restoring a numerically controlled machine tool to its former condition after a power interruption, the numerical control system being of the type in which a position sensor senses the current position of a movable member or of a drive motor of the machine tool and generates a current position signal in accordance with said current position, the movable member being positioned on the basis of a commanded position signal and the current position signal. The positional control information which prevails immediately prior to an interruption in the electric power which is applied to the machine tool and to the numerical control device is stored in a non-volatile memory before the power interruption occurs.

Abstract: A method and apparatus used to compensate for thermal displacement and to correct a positional error caused by the thermally induced displacement of a spindle positioned in response to a numerical control system. The amount of thermally induced displacement of the spindle, at a predetermined point in time after application of electric power to the machine tool, is stored in a memory. When the spindle is to be positioned in response to numerical control data, the commanded amount of spindle movement is compensated by using the amount of thermally induced displacement stored in the memory, and the spindle is then positioned on the basis of the compensated commanded amount of movement.

Abstract: A wire-cut electric discharge machining control method which enables the corner portion at the intersection of first and second tapered surfaces of a workpiece to be cut into a tapered surface of oblique cylindrical shape. With the present invention, the tapered surface of oblique cylindrical shape is formed between the first and second tapered surfaces by entering command data for the radius r of the oblique cylindrical tapered surface in addition to positional control information for cutting the first and second tapered surfaces, computing a pair of points Q and R where the oblique cylindrical tapered surface meets the first and second tapered surfaces from the positional control information and radius, and cutting the tapered surface of oblique cylindrical shape between the points Q and R.

Abstract: A method and apparatus for circular interpolation on the basis of a given arc center O, arc starting point P.sub.s and arc end point P.sub.e. In a case where the given arc end point P.sub.e does not lie on an arc of center O passing through the given arc starting point P.sub.s, a new center O.sub.N of an arc passing through the points P.sub.s, P.sub.e is computed, and circular interpolation is performed on the basis of the computed center O.sub.N, the given starting point P.sub.s and the given end point P.sub.e.

Abstract: A method and apparatus for restoring a broken wire electrode in a wire electrode-type electric discharge machine for machining a workpiece into a desired shape while the workpiece is moved relative to the wire electrode on the basis of machining command data. For effecting the restoration of the wire electrode, memory means are provided for storing the relative machining starting position of the workpiece and the wire electrode at the machining starting point, and the relative wire electrode breakage position of the workpiece and the wire electrode when the wire electrode breaks. After the wire electrode breaks the relative position of the workpiece and the wire electrode is brought into coincidence with the machining starting position on the basis of information indicative of the machining starting position and the wire electrode breakage position.

Abstract: In a control apparatus for residual heat removal system for a nuclear reactor in which the steam generated in the reactor vessel is cooled and condensed into water through a heat exchanger and the condensed water is fed back by a feedwater pump driven by the reactor steam so as to cool the reactor core, the pressure of the condensed water at the exit of the heat exchanger is increased with the rise of the reactor water level so as to decrease the flow of the condensed water, that is, coolant water and the flow-in of the make-up water from the make-up water reservoir communicating with the outlet port of the condenser while the quantity of the reactor steam supplied to the turbine is decreased with the increase in the reactor temperature fall rate so as to decrease the flow of the coolant water fed back into the reactor vessel.