JPS6315093B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an electric discharge machining apparatus that performs machining by applying pulsed discharge to a machining gap where an electrode and a workpiece face each other.

A comparison of a device that performs electrical discharge machining while vibrating the electrode using a conventional vibrating device, in which the vibrator is excited by a machining pulse current, and the vibrating electrode approaches (contacts) and separates from the workpiece. A device that vibrates with a large amplitude has been proposed. This electrode vibration has the effect of removing machining debris and preventing short circuits, but has the disadvantage that the discharge is limited by this large amplitude electrode vibration, making it impossible to increase the number of discharge repetitions.

The present invention was invented to improve this drawback, and includes a high-frequency vibration generator that generates ultrasonic-level vibrations, and an electrode or workpiece that is vibrated by the vibration generator in a machining gap. and a vibration generating device that generates reciprocating vibration at a frequency sufficiently lower than the frequency of the vibration device in the direction of expanding the vibration, and is characterized in that it generates superimposed vibration.

The present invention will be explained below with reference to one embodiment. Reference numeral 1 denotes a machining electrode, and 2 a workpiece. The electrode is fixed to the tip of a horn 3 of a vibrating device, and faces the workpiece 2 to form a machining gap. 4 is a resonator that generates high-frequency vibrations, and is made of crystal, Rothsiel salt, piezoelectric materials such as barium titanate, magnetostrictive materials such as cobalt steel, or electromagnets, but let us now explain the case where a crystal resonator is used. , a crystal equivalently has a capacitance C between electrodes, and an LC resonant circuit can be configured by connecting an inductance L in series to this.
Reference numeral 5 denotes an inductance for configuring the series resonant circuit, and the inductance is selected to match the oscillation frequency, and the series resonant circuit consisting of the crystal resonator 4 and the inductance 5 is connected in series in the machining gap to resonate. The resonance frequency uses a high frequency of 10 to 200 KHz, comparable to ultrasonic waves. Reference numeral 6 denotes a reciprocating vibration device, which attracts and separates the vibrator, 4, horn 3, and electrode 1 elastically supported by an electromagnet 6, and causes the electrode 1 to move reciprocally in the direction of separating the electrode 1 from the workpiece 2 and widening the gap. . 7 is a power source for exciting the electromagnet, which oscillates at a frequency of about 50 to 500Hz. 8 is a servo motor that provides servo feed to the electrode, and 9 is a machining power source that generates machining pulses by charging and discharging a capacitor and controlling on/off switches and applies them to the machining gap, which connects the resonance circuit of the vibrator 4. Connected to the machining gap via.
10 is a high frequency power supply provided as necessary, which is coupled to the inductance 5 of the resonant circuit to generate the resonant frequency.
Energizes high frequency power of 10~200KHz.

In electric discharge machining, electric discharge is generated in the machining gap by pulses supplied by the machining power source 9, and machining is performed by repeating this pulse electric discharge. When electrical discharge is generated in the machining gap, the series resonant circuit of the vibrator 4 and the inductance 5 resonates, and a resonant current flows through the vibrator 4 to generate high-frequency vibrations, which act on the electrode 1 via the horn 3. Since the resonant circuit resonates with the high frequency of discharge, it can be made to resonate with any high frequency depending on the circuit constant, and the electrode 1 can be vibrated at high frequency.

Since the amplitude of the high-frequency vibration of the electrode 1 is normally a minute vibration of about 1 to 3 microns to several tens of microns, the discharge is not limited by this, and the pulse discharge of a predetermined number of repetitions is stably repeated.

Further, the resonance energy is applied to the machining gap superimposed on the pulse discharge and acts on the machining. In addition, due to the vibration of the electrode, the discharge point moves throughout the machining gap, resulting in a uniform and stable discharge, and the generated machining debris, gas, etc. are also eliminated from the vibration, which improves machining speed and improves accuracy. Efficient processing can be performed.

Note that the vibration caused by the vibrator 4 in the illustrated embodiment is not an independent vibration caused by an independent power source, but resonates with the discharge in the machining gap of the series resonant circuit of the vibrator 4 and the inductance 5, and changes in relation to the discharge energy, so that the machining is constantly performed. Since the vibration is controlled depending on the gap, the vibration is always synchronized with the electric discharge and is performed stably in accordance with the machining conditions, making it possible to perform electric discharge machining with extremely high efficiency. Further, when a high frequency is superimposed by the high frequency power supply 10, the stability of high frequency vibration is improved.

However, since the high-frequency vibration caused by the vibrator 4 is a minute vibration as described above, the effect of removing machining debris etc. cannot be expected to be very high, but the electromagnet 6 lifts the low-frequency electrode 1 and separates it from the workpiece 2. By appropriately controlling the frequency and stroke of this reciprocating movement, the high-frequency vibration can sufficiently remove machining debris accumulated during electrical discharge machining. A cleaning action can be performed. For deep hole machining, the vibration stroke can be up to 0.1 to 1 mm.
By increasing this amplitude, the discharge in the machining gap is controlled, but as mentioned above, this reciprocating motion has a sufficiently low frequency of about 50 to 500 Hz, and during this low frequency vibration cycle Since sufficient repeated discharges can be performed for each cycle, this does not limit the discharge repetitions and reduce the machining speed, and the machining gap is cleaned with each low frequency vibration cycle, making the next repeated discharge stable. This increases machining speed and improves machining efficiency.

As described above, by applying vibration to the machining electrode 1 using the high-frequency vibration device and the low-frequency reciprocating motion device, stable machining can be performed, high efficiency machining can be performed, and even deep hole machining can be easily performed. Can be processed.

Note that a resonant circuit for high-frequency vibration may be provided in parallel in the machining gap, or an external capacitor may be connected using the inductance of a vibrator to form a resonant circuit, or the resonant circuit may be a parallel resonant circuit.
By using a resonant circuit, it is possible to perform adaptive control to the machining gap, and in particular, by configuring the resonant circuit using C or L of the vibrator, the device can be easily configured. . Further, this high-frequency vibration generator may generate independent vibrations using an independent oscillator.

Further, the vibration may be applied to the workpiece, and high-frequency vibration may be applied to the electrode, reciprocating vibration may be applied to the workpiece, or vice versa.

[Brief explanation of the drawing]

The drawing is a configuration diagram of an embodiment of the present invention. 1 is a processing electrode, 2 is a workpiece, 3 is a vibration horn, 4 is a high frequency vibrator, 5 is an inductance wire, 6 is an electromagnet for reciprocating motion, and 9 is a processing power source.

Claims (1)

[Scope of Claims] 1. A machining electrode, a machining gap formed between the electrode and the workpiece, a machining power source that supplies machining pulses to the machining gap, and a machining power source that supplies machining pulses to the electrode or the workpiece, and
~10μ, a high frequency vibration device that gives high frequency vibrations with a frequency of about 10 to 200KHz, and a vibration stroke in the direction of expanding the machining gap by elastically supporting the electrode that is vibrated at high frequency relative to the workpiece by the high frequency vibration device. is an electrical discharge machining device characterized by being equipped with a low-frequency vibration device that generates reciprocating vibrations of a maximum of 0.1 to 1 mm and a frequency of about 50 to 500 Hz. 2. Claim 1, wherein the vibration device for applying high-frequency vibration is vibrated by the resonant power of a resonant circuit provided in series or parallel to the machining gap.
The electric discharge machining device described in . 3 The resonant circuit has C of the vibrator of the vibrating device.
The electrical discharge machining apparatus according to claim 2, wherein a series resonant circuit or a parallel resonant circuit is formed using L or L.