JPH02160420A - Wire cut electric discharge machining device - Google Patents

Abstract

PURPOSE:To improve exhaust efficiency of chip by providing a low friction member on the extreme end of a nozzle to block the clearance between the extreme end of a nozzle and a workpiece at being close to or slidably contacted to the surface of workpiece for machining, and major portion of machining liquid to an interpole part for machining. CONSTITUTION:Clearance between the extreme end of a nozzle 7 and a workpiece 12 at being close to or slidably contacted to the surface of the workpiece 12 for machining, is blocked with a low frictional member 14 provided on the extreme end of the nozzle 7. Hereby, wasteful flow-out of machining liquid 10 along the surface of the workpiece 12 is restrained, and blow-in efficiency of the machining liquid 10 to the interpole part for machining is remarkably improved. As the result, exhaust efficiency of chip can be improved. In addition, by a wire electrode 1 having excellent electric conductivity and heat conductivity, Input electric power can be increased and machining speed can be remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a wire-cut electric discharge machining device that can realize ultra-high speed machining.

[Prior Art] FIG. 7 is a configuration diagram showing an example of a conventional wire-cut electrical discharge machining apparatus. In the figure, (1) is the supply bobbin (2)
The wire electrode (3) sent out from the brake roller (4a), (4b), (4) is connected to the electromagnetic brake (3a) and applies a predetermined tension to the wire electrode (1).
c) are idlers that change the running direction of the wire electrode (1). Further, (5) is an upper positioning guide, and (6) is a lower positioning guide, which are arranged inside the upper and lower machining liquid jetting nozzles (7) and (8), respectively. (9) is a pump for supplying machining fluid (lO), (11) is a wire electrode (1) and a workpiece (12)
The wire electrode (1) is supported by the upper positioning guide (5) and the lower positioning guide (6), and the wire electrode (1) is supported by the upper positioning guide (5) and the lower positioning guide (6).
2) is located in a predetermined direction with respect to In addition, (13
) is a wire feed roller.

Next, the operation will be explained. First, wire electrode (1)
A pulse voltage is applied between the wire electrode (1) and the workpiece (12) while spouting the machining fluid (10). Therefore, in the minute gap where the wire electrode (1) and the workpiece (12) face each other, the workpiece (12) is melted and scattered by the thermal energy during the discharge accompanying the vaporization explosion of the working fluid (1O). In addition, the relative movement between the wire electrode (1) and the workpiece (12) in order to keep the opposing micro-gap constant and to continuously perform electric discharge is achieved by numerically controlling an X-Y cross table (not shown). Usually done. By repeating the discharge in this way and controlling the X-Y cross table,
Machining grooves are continuously formed, and the workpiece (1
2) is processed.

In such items, during machining, the machining fluid ejecting nozzle (
The machining fluid (10) spouted from the machining fluid (10) is supplied to the machining section as shown in Figure 8.
0a) and the machining liquid (10b) which leaks from the gap existing between the nozzle tip and the workpiece (12) and flows along the workpiece surface.

[Problems to be Solved by the Invention] In the conventional wire-cut electrical discharge machining apparatus, the machining fluid (lO) spouted from the machining fluid spouting nozzles (7) and (8) during machining is applied to the nozzle tip and the workpiece (12). ) and flows out along the surface of the workpiece, resulting in a problem that the proportion of the machining fluid that contributes to machining is low. Further, the wire electrode (1) also generates heat and is likely to break when the input power is increased, making it difficult to increase the processing speed.

In view of the above points, the present invention provides a wire-cut electrical discharge machining device that can suppress the flow of machining fluid that wastefully flows out along the surface of a workpiece, and can increase machining speed by increasing input power. The purpose is to

[Means for Solving the Problems] The wire-cut electrical discharge machining apparatus according to the present invention has a nozzle tip that closes or comes into sliding contact with the workpiece surface during machining to close the gap between the nozzle tip and the workpiece. In addition to providing a low-friction member, the wire electrode is constructed from a composite wire electrode having a core wire made of a material with excellent electrical conductivity and thermal conductivity, and a brass layer covering the core wire.

[Function] In the present invention, a low friction member is provided at the tip of the nozzle and closes or slides into contact with the surface of the workpiece during machining to close the gap between the nozzle tip and the workpiece. By suppressing the flow of the machining fluid that wastefully flows out along the grooves, the efficiency of blowing the machining fluid into the machining gap can be dramatically increased, and as a result, the efficiency of discharging machining debris is improved. In addition,
By using a wire electrode with good electrical conductivity and thermal conductivity, it is possible to increase input power and dramatically improve processing speed.

[Embodiment] Hereinafter, the present invention will be described with reference to an embodiment shown in FIGS. 1 to 6, in which parts corresponding to conventional ones are denoted by the same reference numerals.

Note that since the machining fluid jetting nozzles (7) and (8) both have the same configuration, only the upper machining fluid jetting nozzle (7) will be illustrated and explained in an enlarged manner. The wire-cut electrical discharge machining device of this embodiment has a machining fluid jet nozzle (7).
An annular recess (7a) is carved in the tip, that is, the end face facing the workpiece (12), and the annular recess (7a) has a lower coefficient of friction than the machining fluid spouting nozzle (A). An annular low friction member (14) is fitted. In addition, the low friction member (14) is set so that its tip surface slightly protrudes from the nozzle tip, and during electrical discharge machining, it slides into contact with the workpiece surface and creates a gap between the nozzle tip and the workpiece (12). It acts to close the gap.

Therefore, during machining, the machining fluid (10) spouted from the machining fluid jetting nozzle (7) flows along the surface of the workpiece from the gap between the nozzle tip and the workpiece (12), as shown in FIG. The machining fluid that is about to flow is prevented from flowing out by the low friction member (14), and the machining fluid (
The flow rate of step 10a) is increased, and the efficiency of blowing into the machining gap is improved.

Figure 3 shows an experimental method for quantitatively understanding the effect of improving the blowing efficiency mentioned above.
A funnel-shaped hood (15) is placed at the opening side end of the groove (12a) formed with the wire electrode (1), so that only the machining liquid (10a) blown between the machining electrodes can be taken out, and the The processed liquid (10a) is collected in a container (16).

Figure 4 shows the processing fluid (10
It is an explanatory diagram showing the amount of a) in comparison with a conventional one,
The vertical axis shows the blowing flow rate (1), and the horizontal axis shows the hydraulic pressure. From the same figure, it can be seen that the flow rate of blowing into the machining machining gap is significantly increased in this example compared to the conventional one.

FIG. 5 is a cross-sectional view showing an example of the wire electrode according to this embodiment, and this wire electrode (1) has a core wire (
1a) Add a material with excellent electrical and thermal conductivity, such as tin, to O
, 15vt%, and is constructed as a composite wire electrode in which a core wire (1a) made of this copper alloy is coated with a brass layer (1b).

The wire electrode (1) is made of a composite wire electrode having a core wire (1a) with good electrical conductivity and thermal conductivity. It can be efficiently transmitted to the back side, and the brass layer (
It is possible to promote a reduction in the consumption of lb), and it is also easy to increase input power, contributing to an increase in processing speed.

Figure 6 shows a combination of machining fluid jet nozzles (7), (8) (see Figure 1) equipped with low-friction members (14) and a wire electrode (1) (Figure 5) consisting of a composite wire electrode. FIG. 2 is an explanatory diagram showing the speed of electric discharge machining by the apparatus of this embodiment in comparison with the conventional one, with the machining speed being plotted on the vertical axis and the hydraulic pressure being plotted on the horizontal axis. As is clear from the figure, the processing speed of the apparatus of this embodiment is lower than that of the conventional one due to the synergistic effect of the low-friction member (14) to increase the blowing flow rate between the machining electrodes and the heat transfer effect of the composite wire electrode. It can be seen that it is improved.

In the above embodiment, the core wire is made of a copper alloy containing tin, but the same effects as in the above embodiment can be obtained even if the core wire is made of a copper alloy containing silver, for example. If so, the mechanical strength will be slightly reduced, but the conductivity will be improved.
Since the thermal conductivity was further improved, it was easier to increase the input power, and good results were obtained in terms of processing speed. Others include silver, aluminum, or those as main components.

Similar effects were obtained with the alloy.

Further, in the above embodiment, the low friction member (14) was brought into sliding contact with the surface of the workpiece (12), but the low friction member (14) may be brought into close contact with the surface of the workpiece (12), although the efficiency is slightly lowered.

[Effects of the Invention] As described above, according to the present invention, a low-friction member is provided at the tip of the ζf1 nozzle in close proximity to or in sliding contact with the surface of the workpiece during machining to close the gap between the nozzle tip and the workpiece. In addition, since the wire electrode was constructed from a composite wire electrode 1 having a core made of a material with excellent electrical and thermal conductivity and a brass layer coated on this core, conventionally the nozzle tip and the workpiece were It is possible to blow most of the machining liquid that flows out along the surface of the workpiece from the gap between the workpiece and the workpiece into the gap between the machining electrodes, and the wire electrode has excellent electrical and thermal conductivity. , it has the effect of increasing the machining speed by inputting a large amount of power to the wire electrode, and by increasing the machining speed, the running cost of the machine can be reduced, and the machining speed is faster than that of normal machining. Since the difference in speed can be eliminated, parts machining, which conventionally relied on mechanical machining methods, can be realized by wire force/soto electrical discharge machining with good machining accuracy.

[Brief explanation of the drawing]

Fig. 1 is an enlarged longitudinal cross-sectional view of one embodiment of the machining liquid jetting nozzle according to the present invention, Fig. 2 is a partially enlarged view for explaining its operation, and Fig. 3 shows the machining liquid jetting nozzle between machining machining holes. Fig. 4 is an explanatory diagram for explaining the method of measuring the machining fluid used in machining. FIG. 5 is a cross-sectional view showing an enlarged example of the wire electrode according to the present invention;
Fig. 6 is an explanatory diagram showing a comparison of actual machining speeds between the conventional one and the one of this embodiment, Fig. 7 is a configuration diagram showing an example of a conventional wire-cut electrical discharge machining device, and Fig. 8 is FIG. In the figure, (1) is a wire electrode, (1a) is a core wire, (
1b) is the brass layer, (5) is the upper positioning guide, (6)
is a lower positioning guide, (7) and (8) are machining fluid jet nozzles, (10) is machining fluid, (11) is a pulse power supply unit, (12) is a workpiece, and (14) is a low friction member. . In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A wire-cut electric discharge machining device that performs electric discharge machining by applying a pulse voltage from a machining power source while supplying machining fluid from a nozzle that guides the wire electrode at the axial center to a minute gap where the wire electrode and the workpiece face each other. A low-friction member is provided at the tip of the nozzle to surround the wire electrode and close to or slide into contact with the surface of the workpiece during processing to close the gap between the tip of the nozzle and the workpiece, and A wire-cut electrical discharge machining device characterized in that the wire electrode is constituted by a composite wire electrode having a core wire made of a material with excellent electrical conductivity and thermal conductivity, and a brass layer coated on the core wire.