JPS60186320A - Wire-cut electrical discharge machine - Google Patents

Abstract

PURPOSE:To prevent the aerial discharge due to the shortage of the amount of working liquid by installing a working electric current detector into a conduction circuit for working energy and controlling a working-liquid feeding system such as pumps, etc. according to the detection signal, in a wire-cut electrical-discharge apparatus. CONSTITUTION:The relative feed in a prescribed working shape is provided between a wire electrode 1 which traveling-shifts and a work 3 through NC, etc., and pulse electric conduction is applied from a pulse power source 4, jetting-out working liquid onto a worked part from the upper and lower nozzles 5, and working is proceeded by repeating the electrical discharge. The working electric current is detected by an electric current detector 9, and a pump 6 is controlled so that the hydraulic jet stream corresponding to the detection signal is carried- out by an inverter 10. The detection signal of the electric current detector 9 is application-controlled by the average working electric current value which varies according to the working state or a repose time width as detection signal. Therefore, a proper amount of working liquid is always supplied, and the generation of disconnection is prevented, and stable working can be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a wire-cut electrical discharge machining apparatus, particularly in machining fluid supply control.

In a conventional wire-cut electric discharge machining apparatus, machining fluid is jetted and supplied from nozzles that face each other from above and below a machining section of a workpiece, but the jet pressure, jet amount, etc. are manually set. However, during machining, if the amount of machining fluid supplied is insufficient due to changes in machining conditions, aerial discharge occurs and the wire electrode sometimes breaks.

In order to improve this point, the present invention provides a machining current detector in the machining energy energization circuit, and controls a machining fluid supply system such as a pump based on a signal from the detector.

The present invention will be explained below with reference to an embodiment of the drawings.

In FIG. 1, reference numeral 1 denotes a wire electrode in the form of a wire, a band, etc., which is supplied from a reel (not shown) in which it is wound and stored, and runs and moves with a predetermined tension and speed as shown by the arrow. On the way, it moves between the upper and lower guides 2, and electrical discharge machining is performed with the workpiece facing the wire electrode 1 between the guides. 4 is a pulse power source that supplies processing pulses between the wire electrode 1 and the workpiece 3; 5 is a nozzle that supplies processing liquid such as distilled water toward the processing part of the workpiece 3; It is set in. 6 is a pump, which divides the liquid into two by a flow divider 7 midway through both nozzles 5.
supply to. 8 is a machining fluid storage tank, 9 is a current detector inserted into the energizing circuit of the machining pulse power source 4, and 10 is an inverter that controls the pump 6 based on a detection signal.

i! :'j In machining, a relative feed of the required machining shape is given between the moving wire electrode 1 and the workpiece 3 by NC control etc., and a pulse lightning [4 Machining progresses by applying more pulse current and repeating discharge. A machining current is detected by a current detector 9, and an inverter 10 controls the pump 6 to generate a hydraulic jet in response to the detection signal. The detection signal of the current detector 9 is adaptively controlled by using the average machining current value or the pause time width (τoff) which changes depending on the machining state as the detection signal.

Figure 2 is an experimental graph of 55 mm with a thickness of 1001 Ill Il.
When wire-cutting 5C material, the wire electrode has a wire diameter of 0.
A 3s wire of 2 mmφ was used while moving at a running speed of 2 m/1 nin, and the processing fluid was treated with an ion exchange resin and processed using water with a specific resistance of 5×10 4 Ωchi. Stable machining is performed with an average machining current of 10 A and a jet liquid pressure of 4 kg/cm2, and the machining speed is 100 n+n+2/mi.
There was no disconnection of the wire electrodes at n. The pause time width τoff in this case was about 20 μs. Next, when the average machining current was 20 A, the hydraulic pressure was 16 ks/c2, the machining speed was about 20 On+ll12/min, and there was no wire breakage. τoff in this case was approximately 7 μs. Next, when the average machining current was 30 A and the hydraulic pressure was 32'j)/cm2, a machining speed of about 320 mm2/min was obtained, and there was no wire breakage. τoff was approximately 5 μs.

By adaptively controlling the machining fluid pressure in this way, the appropriate amount of machining fluid is always supplied to the machining gap according to the machining conditions such as the cutting speed, and the cooling effect of the wire electrode is sufficiently achieved.This eliminates wire breakage and stabilizes the process. can be processed and the processing speed can be improved.

As described above, the present invention detects the average machining current or pause width τoff using a current detector, and uses this as a signal to supply a jet of machining fluid at the corresponding hydraulic pressure from the nozzle 5 as shown in FIG. Since the pump device is controlled, an appropriate amount of machining fluid can be supplied at all times, and stable machining can be performed without disconnection.

The machining fluid pressure controlled in response to the average machining current or pause width signal is shown in Figure 2 for the above experimental example.
This value varies depending on the shape and dimensions of the machining fluid jet nozzle 5 and the installation method of the nozzle tip. Test measurements as shown in Figure 2 are performed in advance using mechanical equipment, and fluid pressure control is performed based on the measurement results. Of course, this must be done. Flow rate control may be performed in addition to hydraulic pressure.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention, and FIG. 2 is an experimental graph diagram thereof. 1...Wire electrode 2...Guide 3...Workpiece 5- 4...Pulse power supply 5... Machining liquid jet nozzle 6...
Pump 9 Current detector 10 Control inverter patent applicant 61

Claims (1)

[Scope of Claims] (1) A wire-cut electric discharge machining device that performs electric discharge machining by applying pulse current from a machining power source while supplying machining fluid from a pump in a jet stream from a nozzle to the gap between a wire electrode and a workpiece facing each other. Wire-cut electrical discharge machining, characterized in that a machining current detector is provided in the energization circuit from the machining power source, and a control device is provided for controlling a machining fluid supply system including the pump based on a signal from the detector. Device. (2) The wire-cut electrical discharge machining apparatus according to claim 1, further comprising a control device that controls the machining fluid supplied by the pump based on the τoff signal of the machining current detector. (3) The wire-cut electrical discharge machining apparatus according to claim 1, further comprising a control device that controls the machining fluid supplied by the pump based on the average machining current signal of the machining current detector.