METHOD OF ELECTROEROSION MACHINING OF PARTS AND DEVICE FOR EFFECTING SAME

• US 3,671,705 A
• Filed: 08/12/1970
• Issued: 06/20/1972
• Est. Priority Date: 07/06/1967
• Status: Expired due to Term

• Current Assignee: Mikhail Alexeevich Raznitsyn, UL Arbat 54/2, Moscow Soviet Union
• Original Assignee: Mikhail Alexeevich Raznitsyn, UL Arbat 54/2, Moscow Soviet Union
• Inventors: Moscow, Soviet Union, Mikhail Alexeevich Raznitsyn, UL Arbat 54/2
• Primary Examiner(s): R. F. Staubly
• Application Number:
  US05/063,296
• Time in Patent Office: 678 Days
• Field of Search: 219/69C,69R,69G,69P,69V
• US Class Current: 219/69.13
• CPC Class Codes: B23H 7/065 Electric circuits specially adapted therefor

Abstract

A method and device for effecting electroerosion machining comprises a high-frequency source of pulses of a relatively low amplitude of current and a low-frequency source of pulses of a relatively high amplitude of current controlled by circuits for automatically switching over said sources in response to a decrease in the interelectrode gap value and for switching them back after a predetermined period of time. Alternatively a source of variable frequency of pulses of electric energy with a high amplitude of voltage may be employed with a pulse step-down transformer and circuits for automatic decrease of the frequency of the source and its direct connection with the electrodes for a predetermined period of time in response to a decrease in the interelectrode gap value, there being provided control elements for disconnecting the windings of the transformer and directly connecting the high-voltage source with the electrodes, and for restoration of the circuits after a predetermined period of time.

Claims

1. A method of electroerosion machining comprising supplying periodic pulses of electric energy with a relatively highfrequency and comparatively small amplitude of current from an intermittent current source to a gap between a tool and a workpiece serving as electrodes, displacing the tool relative to the work-piece at a controlled speed in forward-stop operating conditions, supplying to the gap periodic pulses of electric energy with a comparatively high amplitude of current of a relatively low-frequency simultaneously with said high-frequency pulses during a predetermined time period in which said gap is non-existent and the electrodes are in contact with one anothEr, restoring the gap to its predetermined value, and, discontinuing the supply of the low-frequency pulses and resuming the relative movement of the electrodes after the predetermined value of the gap is restored.

2. A method of electroerosion machining comprising supplying periodic pulses of electric energy with a relatively high frequency and comparatively small amplitude of current from an intermittent current source to a gap between a tool and a work-piece serving as electrodes, displacing the tool relative to the work-piece at a controlled speed in forward-stop operating conditions, discontinuing the application of the pulses and the relative movement of the electrodes during a predetermined time period in which said gap is non-existent and the electrodes are in contact with one another, while supplying the gap with periodic pulses of electric energy with a relatively low-frequency and comparatively high amplitude of current, restoring the gap to its predetermined value, and discontinuing the supply of the low-frequency pulses and resupplying the high-frequency pulses and resuming the relative movement of the electrodes when the predetermined value of the gap is restored.

3. A device for electroerosion machining comprising a tool disposed with a gap relative to a workpiece, said tool and workpiece constituting electrodes, means for displacing the tool relative to the workpiece along a predetermined trajectory at a controlled speed in forward-stop operating conditions, and means for selectively feeding to said tool and workpiece short periodic pulses of energy of a relatively high-frequency with a comparatively low amplitude of current and in a predetermined period of time when the gap is non-existent short periodic pulses of energy of a relatively low-frequency with a comparatively high amplitude of current.

4. A device for electroerosion machining comprising a tool disposed with a gap relative to a workpiece, said tool and workpiece constituting electrodes, means for displacing the tool at a controlled speed in a forward-stop operating condition, a supply source of periodic high-frequency pulses of a relatively small amplitude of current;

and means automatically actuated in response to a decrease of the value of the gap to zero to apply, across said gap, in a predetermined period of time periodic low-frequency pulses of a relatively high amplitude of current.

5. A device for electroerosion machining comprising a tool disposed with a gap relative to a workpiece, said tool and workpiece constituting electrodes, means for displacing the tool relative to the workpiece along a predetermined trajectory at a controlled speed in a forward-stop operating condition, a supply source of periodic high-frequency pulses of a relatively small amplitude of current connected to said electrodes for producing pulse discharges across said gap, means for applying periodic low-frequency pulses of a relatively high amplitude of current to said electrodes and across the gap when its value is zero;

and means automatically actuated with a predetermined delay in time in response to actuation of the first said means to discontinue, after a predetermined period of time, the supply across the gap of the relatively low-frequency periodic pulses of energy and start again the supply across the gap only of the periodic relatively high-frequency pulses of energy with the comparatively low amplitude of current.

6. A device for electroerosion machining comprising a tool spaced with a gap relative to a workpiece;

said tool and workpiece constituting electrodes;

a source of periodic pulses, for producing across said gap, pulses of energy of a relatively high-frequency with a comparatively low amplitude of current to carry out electroerosion machining;

a source of periodic pulses, for producing across said gap, pulses of energy of a relatively low-frequency with a comparatively high amplitude of current for carrying out electroerosion machining when the value of the interelectrode gap is zero And the electrodes are in contact with one another;

control circuits for switching on said source of low-frequency pulses with high amplitude of current in response to a decrease of the interelectrode gap to zero and for switching it off after a predetermined period of time; and

a diode for separating the circuits of both said sources of periodic pulses of energy.

7. A device for electroerosion machining comprising a tool spaced with a gap relative to a workpiece;

said tool and workpiece constituting electrodes, a source of periodic pulses, for producing across said gap, pulses of energy of a relatively high-frequency and a comparatively low amplitude of current for carrying out electroerosion machining;

a source of periodic pulses, for producing across said gap, pulses of energy of a relatively low-frequency and a comparatively high amplitude of current for carrying out electroerosion machining when the value of the interelectrode gap is zero and the electrodes are in contact with one another;

control circuits for disconnecting from the electrodes the source of pulses of high-frequency and low amplitude of current and connecting to the electrodes the source of pulses of low-frequency and high amplitude of current in response to a decrease of the interelectrode gap to zero, and for switching off the source of pulses of low-frequency and high amplitude of current and switching on the source of pulses of high-frequency and low amplitude of current after a predetermined period of time; and

a commutating element controlling said control circuits for connecting and disconnecting the electrodes with said sources of pulses.

8. A device for electroerosion machining comprising a tool spaced with a gap relative to a workpiece;

said tool and workpiece constituting electrodes;

a source of periodic pulses of energy with a variable frequency and a high amplitude of voltage;

a pulse step-down transformer for decreasing the voltage of the pulses of energy supplied to the electrodes;

a control circuit for automatically switching off said transformer and decreasing the frequency of periodic pulses of the source in response to a decrease of the value of the interelectrode gap below a predetermined value and for restoring, after a predetermined period of time, the connection of said transformer and the frequency of the periodic pulses of the source, a commutating element controlling said control circuit and inserted in the circuits of the primary and secondary windings of said transformer to automatically break said primary and secondary windings of the transformer and connect the source of the pulses of high voltage with the electrodes in response to the actuation of said control circuit and to restore the connection of said circuits of the transformer in response to the switching-off of the control circuits after a predetermined period of time.