Abstract: A chip-mounting portion of a flexible cable (18) having a light-receiving element chip mounted thereon is placed on a shielding plate (22), and a pattern portion (15b) on a fixed coding plate (15) and the shielding plate (22) are grounded, thereby shielding the periphery of the light-receiving element chip to improve noise tolerability with respect to noise generated internally.

Abstract: A digital servor system can swiftly stop a moving object, having a small friction resistance to the motion, at the position where the object should stop, without vibration thereof. A velocity command generating device (3) calculates a velocity command (V.sub.cmd) based on the deviation value of a position fedback from a position command detected by a position deviation detecting device (2). A velocity deviation detecting device (5) calculates a deviation (E) of a velocity fedback from the velocity command (V.sub.cmd). A torque command generating device (6) calculates a torque command (T.sub.cmd) giving a delay processing to the deviation (E), and outputs the torque command (T.sub.cmd) to a motor driving means (7).

Abstract: When cutting workpiece into a desired number of closed loop configurations by means of a wire-cut, electric discharge machine provided with an automatic wire feed mechanism, electric discharge machining is started from a machining start hole made in the workpiece corresponding to each closed loop configuration and is performed to a point where the electric discharge machining operation is stopped, thus a part of the closed loop configuration is left uncut. After fixing at least one portion of each closed loop configuration to the workpiece and inserting the wire electrode into the machining start hole by the automatic wire feed mechanism, the electric discharge machining operation is resumed to cut off the remaining uncut part.

Abstract: A wire electrode pull-up mechanism in a wire-cut electric discharge machine having an energized wire electrode stretched between upper and lower guides for machining a workpiece wherein the wire electrode pull-up mechanism pulls up a wire electrode which has been passed through a bore in the workpiece until the upper end of the wire electrode protrudes from the upper side of the workpiece, and includes a gripping member for gripping the wire electrode.

Abstract: A wire-cut, electric discharge machining method in which a wire is inserted into a machining start hole made in a workpiece to start electric discharge machining from the machining start hole, a bushing of a conductive material is pressed into a hole made in the workpiece to provide the machining start hole.

Abstract: A wire-cut, electric discharge machine in which a pair of rollers are provided in the vicinity of each of the upper and lower guides of a wire running system for gripping therebetween a wire with constant pressure. When the wire breaks, the pairs of rollers hold the wire to prevent it from coming off the running system.

Abstract: A wire-cut, electric discharge machine which is provided with auxiliary wire feed means for feeding a wire in a backward direction when the wire is broken, and a wire detector for detecting, at a predetermined position, the extreme end of the broken wire fed in the backward direction. When detecting the extreme end of the broken wire by the wire detector, the feed of the broken wire by the auxiliary wire feed means is stopped to position the extreme end of the broken wire at a predetermined position.

Abstract: A wire or band electrode type electric discharge machine for machining hard metals by an electric spark generated between the metal workpiece and a wire electrode which is fed longitudinally to provide a fresh supply thereof while a prescribed relative motion is established between the workpiece and the wire electrode. The invention provides a clamping mechanism on the wire supply side of the workpiece for clamping the wire electrode if it breaks during operation, and a wire electrode feed mechanism for automatically guiding the broken end of the wire through the opening that has been machined in the workpiece. A wire electrode pull-up mechanism is provided on the other side of the workpiece for gripping and pulling up the wire electrode. If the electrode wire breaks during a machining operation, the clamping mechanism immediately clamps the wire electrode and prevents it from falling under its own weight.

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.