JPS62107921A - Wire-cut electric discharge machining method - Google Patents

Abstract

PURPOSE:To promote the movement and discharge of bubbles and machined chips, by allowing the impinging point between both side jet liquids to move so that the impinging point is controlled to move at a specific speed. CONSTITUTION:Jet streams of machining liquid from both upper and lower nozzles 5, 6 are controlled in such a way that valves 8, 9 are normally and reversely associated with each other by means of a motor 10. Accordingly, when the jet stream pressures of machining liquid from both nozzles 5, 6 become equal to each other, the impinging point between jet streams of the liquid is created at a substantially middle point of the plate thickness of a workpiece 3. Further, when the jet stream pressure of the upper nozzle 5 becomes lower, the impinging point of jet streams is moved downward. The moving speed of the impinging point is controlled in accordance with the control speed of both valves 8, 9 driven by the motor. Further, the machining speed is abruptly increased when moving speed of this impinging point is about 3 m/min. This is due to that generated bubbles and machined chips comes to be easy to be moved and discharged.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to improvements in wire cut electric discharge machining.

[Prior art and problems]

In wire-cut electrical discharge machining, when a jet of machining fluid is supplied from opposing nozzles from both the upper and lower sides of a workpiece through which a wire electrode penetrates, conventionally, the collision point of the jets of machining fluid from both sides was at a point equal to the thickness of the workpiece. I adjusted it so that it was approximately in the middle, and processed it so that it would always maintain that position. However, subsequent experiments revealed that air bubbles and machined chips generated at the collision point of the liquid jet gather and become stagnant, causing arc discharge and short circuits to occur, leading to wire breakage.

[Means for solving problems]

Therefore, the present invention is characterized in that the collision point of the liquid jets on both sides is moved, and the collision point is controlled to move at a speed of 3 m/min or more based on experimental results.

〔Example〕

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

Reference numeral 1 denotes a wire electrode, which is supplied from a reel (not shown) and is moved between guides 2 in the direction of the arrow with the required tension and speed by means of a brake and a take-up roller. Reference numeral 3 denotes a workpiece, which forms a machining gap in opposition to the wire electrode 1 moving between the guides 2, and is machined by generating pulsed discharge. 4
5.6 is a machining power source that supplies pulses, and 5.6 is a nozzle that supplies a jet of machining liquid toward the machining part from both the upper and lower sides of the workpiece. Supplied. Reference numeral 10 denotes a control motor that circulates and controls both valves 8 and 9 in the forward and reverse directions.As the jet from nozzle 5 becomes stronger, the jet from nozzle 6 weakens, and conversely, the jet from nozzle As the jet flow weakens, the jet flow from the nozzle 6 becomes stronger, and the jet flow is circulated to control changes.

11 and 12 are motors that drive the table 14 in the X and Y axes, and 13 is its NC control device.

Wire cutting is performed by giving a machining feed in a shape programmed by the NC control device 13 between the workpiece 3 and the penetrating wire electrode 1, and applying pulses from the machining power source 4 to repeat pulse discharge to perform electrical discharge machining. . The machining fluid is supplied by jetting from the upper and lower nozzles 5.6 in the direction in which the wire A7 electrode of the workpiece machining section penetrates, and is interposed in the discharge gap where the wire electrode 1 and the workpiece 3 face each other. It acts as a discharge medium, has a cooling effect, and has the effect of eliminating processed chips, air bubbles, etc. This prevents arcs and short circuits, prevents wire electrode breakage, and contributes to stable machining.

Thus, the jet flow of machining fluid from both the upper and lower nozzles 5.6 is controlled by the valves 8 and 9 being interlocked in forward and reverse directions by the motor 10. Therefore, when the jet pressures of the machining fluid from both nozzles 5 and 6 become equal, a collision point of the jet fluid is formed at approximately the center of the thickness of the workpiece 3, and the jet pressure of the upper nozzle 5 is When the jet pressure becomes small, the jet liquid collision point moves upward in the machining gap, and conversely, when the jet pressure of the lower nozzle 6 becomes small, the collision point moves downward. The moving speed of this collision point is controlled by the control speed of both valves 8.9 by the motor 10, and can be arbitrarily controlled.

Figure 2 is a graph of the experimental results of machining speed when machining was performed by changing and controlling the moving speed of the collision point of the jet liquid, and the machining conditions were to process SKD material using a BS wire with a wire diameter of 0.25n+n+φ as a wire electrode. When, Ip=260A, τon=
With a pulse of 1.6μs, the specific resistance of the machining fluid is 5X 104
Water of Ωcm was used. As can be seen from the graph, the effect of rapidly increasing the machining speed was seen when the moving speed of the collision point of the jet liquid was about 3 g+/gin, and the moving speed increased to about 8 m/min.
It can be seen that when the collision point is stationary (velocity OWL), the machining speed increases by about twice compared to the case where the collision point is stationary (velocity OWL). This seems to be due to the effect of preventing wire breakage, etc.

In the case of the above embodiment, the jet liquid collision point was moved by controlling the jet pressure from both nozzles, but it may also be performed by controlling the jet pressure from one nozzle, or by moving the jet liquid collision point between the nozzles facing the processing part. By controlling the rotation of the angle, the position of the collision point and the speed of movement of that position can be controlled by controlling the switching of a plurality of nozzles facing different angles. It is also possible to control the workpiece by moving it up and down.

According to the above experimental example, the effect is seen at a moving speed of 3 m/n+in or more, which is a value approximate to the traveling speed of the wire electrode, indicating that the effect is effective at a speed of about the wire moving speed or higher.

〔Effect of the invention〕

As described above, in wire cutting, the present invention supplies machining fluid to the workpiece by jetting it in the penetrating direction of the wire electrode from opposing nozzles from both sides of the workpiece, and the fluid jetted from both nozzles is The point of collision is 3 in the direction of wire electrode penetration.
Since the jet flow of both nozzles is controlled to move at a speed of m/win or more, this facilitates the movement and removal of bubbles and machining chips generated by electric discharge.
It is possible to improve stable workability by preventing arcs and short circuits, improve the cooling effect of the wire electrode to prevent wire breakage, and increase processing speed by applying electricity at a high current density.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an apparatus according to an embodiment of the present invention, and FIG. 2 is an experimental graph diagram. 1...Wire electrode 2...Guide 3...Workpiece 4...Machining power supply 5 .6-...Nozzle 7...Pump 8.9...Valve 10...Motor patent issued Applicant: Representative of Inoue Ji17 Backs Research Institute, Inc. Kiyoshi Inoue '7'Heko;t21;i

Claims (1)

[Claims] In the wire-cut electrical discharge machining method, electrical discharge machining is performed while supplying machining fluid and machining pulses while applying relative machining feed in substantially orthogonal directions with a wire electrode moving a guide passing through the workpiece. The liquid is supplied from both sides of the workpiece so that it is jetted in the penetrating direction of the wire electrode by opposing nozzles, and the collision point of the liquid jetted from the nozzles on both sides is 3 m/m in the penetrating direction of the wire electrode.
A wire-cut electrical discharge machining method, characterized in that the jet flow of both nozzles is controlled so that the nozzles move at a speed of in or more.