摘要:
A head assembly for an electro-erosion machine tool comprises, in a housing, a guide for guiding the moving filamentary or strip-form tool electrode and first contact means for supplying erosion energy to the electrode. The scavenging medium is fed into the housing so as to cool the contact means and guide, and leaves it by way of a nozzle through which also the electrode leaves the housing on its way to another head assembly arranged on the opposite side of the location where machining is performed, the scaverging medium being thereby fed to the machining location as an envelope coaxial to the electrode. Second contact means for contacting the workpiece to be machined are fixed to the nozzle and the connections to each contact means are arranged for low inductive energy loss.
摘要:
To provide constant tension on an electro-erosive electrode machining wire, tape or ribbon stretched in a working path between advancing rollers and pulling rollers, a tension loading arrangement, for example weights, springs, or the like, are applied to the wire to maintain the tension thereof at a constant value. The deflection of the wire, due to elongation thereof as a result of heating, differences in manufacturing technologies and the like, is sensed and fed back to the motors driving the advancing and pulling rotors to maintain the tension, as controlled by the motor torques and speeds at a uniform value.
摘要:
Electroerosion machining (EDM or ECM) is carried out with a minimum of manual intervention. Under control of recorded data an electronic control system utilizing control logic directs the set-up operations as well as the actual machining process. The operations automatically (i.e., without the necessity of manual intervention) include loading and removal of workpieces and electrode material, trueing up of the workpiece (which may be by providing a transformation of the data rather than by adjusting the position of the workpiece), making starting bores, threading the electrode through a starting bore, applying a low melting alloy or other conducting adhesive to cement a core in the process of being cut out by machining, cutting the electrode after completing a starting bore and joining electrode ends after rethreading in a new starting bore. In threading the electrode it may be pushed simply or with the support of a surrounding jet of pressure medium, or it may be pulled by a grapple member.
摘要:
A pulse generator for use in forming the erosion pulses of an electro-erosion machine tool comprises means for forming two envelope curve signals representing upper and lower limit levels for the instant level of the output pulse, a comparing device for comparing the actual current level of the output pulse with the envelope curve signals, and a current supply for forming the pulse under the control of a switch which is turned on and off by the comparing means in such a way as to maintain the output pulse current level in the region represented by the space between the envelope curves.
摘要:
The peak voltage of each discharge pulse is measured and, if the voltage of the pulse exceeds a high threshold value, there is also measured the time between the passing of that value and the moment the pulse voltage thereafter drops below a second lower threshold value. The two measurements are expressed in pulses that are combined, preferably by addition, to provide a regulating value, whose deviation ("error") from a standard value is predicted for a coming period, taking account of recent electrode position change as well as regulating value trend. The sign of the predicted error determines in which direction the electrode drive motor will be energized, but if the predicted error is less than a threshold value no motor energization occurs until the next error prediction. The sense in which the regulation operates is so defined that at a time when the electrodes are not already in relative movement an increase in the regulating value, at least if it persists, causes the electrodes to be moved closer together.
摘要:
An apparatus for shaping a three-dimensional workpiece by inducing the following relative motions between an abrading die member and the workpiece: a feed motion, periodical retract and advance motions in a z-direction, and a planetary or orbital motion in the x and y directions. The mechanism which generates the planetary or orbital motion is provided with means for infinitely adjusting the eccentricity of this motion and is provided with means for selectively and releasably fixing the chosen amount of eccentricity. An assembly is provided to adapt the following process values to conditions within a gap between the die and the workpiece such that the abrading process is optimized: (i) feed pressure between the die and the workpiece during an abrading period of a work cycle; (ii) speed of the feed motion; and (iii) speeds of periodical retract and advance motions.
摘要:
In order to provide respective series of control signals for controlling separate items of apparatus, some of which may be redunant, there are provided a plurality of independently operable signal generators and a plurality of gating circuits connected to the generators and each operable to produce a respective control signal when it receives at least a predetermined number, dependent upon a chosen degree of redundancy of the generators, of correctly timed signals from the generators. Each generator is provided with a phase comparator type timing control device which adjusts the generator if its signals go out of synchronism with those of the other generators. The apparatus to be controlled can be a computer, a multiple-rectifier power supply or the like, and in connecting lines between various parts of the control apparatus and the controlled apparatus isolating devices can be provided.
摘要:
In a spark erosion machine in which the tool electrode comprises a tensioned flexible wire or tape, machining induced force due, for example, to the magnetic and electric fields induced by the sparks, act on the tool electrode and may cause it to vibrate. To reduce the tendency for such vibration, a compensating signal is passed through the tool electrode or applied between the tool electrode and workpiece so as to produce a magnetic or electric field which compensates for the machining induced forces. The compensating signal is preferably adjustable in magnitude and/or frequency (the latter assuming it is an alternating signal) and the output of the generator which produces it is decoupled from the output of the spark pulse generator. The spark pulse generator and the compensating signal generator may be interdependently synchronized by a synchronizing signal lead connected between them.
摘要:
A main and an auxiliary energy supply device supply energy to a load normally and during disturbances of the main supply respectively while, for bridging brief disturbances in the load supply, for example naturally brief disturbances or during the short time when a disturbance has begun and the auxiliary supply has not yet come into operation, there is provided an energy store which can receive and store energy from the main supply and make this stored energy quickly available to the load. A control logic system controls the main and auxiliary supply devices and the storage means to ensure substantially constant energy supply to the load. The disturbances in question may comprise voltage rises or reductions and/or waveform distortions for example.
摘要:
A pulse generator for metal machining by electric discharges, comprising a primary current circuit for producing and transmitting pulse forms to a pair of electrodes. A voltage and/or current source is arranged in the low-ohm and low-loss primary current circuit, the voltage of which has a value which is only that much greater than the operating voltage of the pulses flowing through the spark gap as is needed to positively overcome the voltage losses occurring in the primary current circuit. A signal generator produces a signal corresponding to the desired current pulse shape or form. A comparator, which has a switch arranged in the primary current circuit for regulating the current flow in such primary current circuit, controls the current flowing through the primary current circuit, as a function of the desired pulse form produced by the signal generator and a magnitude of the current flowing in the primary current circuit which is tapped-off by a measuring feeler. A magnetic energy storage arranged in the primary current circuit and having a switch in parallel to the work gap produces a voltage having a value greater than the voltage of the current and/or voltage source, and the primary current circuit is designed such that there is only present stray capacitance.