JPH02139130A - Wire-cut electro-discharge machining unit - Google Patents

Abstract

PURPOSE:To restrain a variation in a gap between a workpiece and a wire electrode so easily at all times as well as to improve the extent of electro- discharge machining accuracy by forming a tension restraint means, restraining a fine tension variation of the wire electrode wit an almost semicircular consistent body surrounding this wire electrode. CONSTITUTION:A microscopic tension variation of a wire electrode 10 to be added, as being delivered, by inertia force of a rotating bobbin 12 is restrained by frictional force being produced in space between an almost semicircular consistent body 76, surrounding the wire electrode 10, and this electrode 10 and deformation of this consistent body 76. In consequence, travel of the wire electrode 10 at a machining area is stabilized and the tension is kept constant. Consequently, the electro-discharge machining accuracy is thus improvable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wire electrical discharge machining apparatus equipped with a tension suppressing means for suppressing fluctuations in tension of a wire electrode.

[Prior Art] FIG. 4 is an explanatory diagram of the configuration of a conventional wire electric discharge machining apparatus.

In Fig. 4, (1G) is a wire electrode, (12) is a bobbin, (14a), (14b), (14c)
, (14d) is an idler. Idler (14a)
~(14d) supports and guides the wire electrode (lO) at a change point in the running direction. (1G) is a wire collecting means for collecting the processed wire electrode, and is driven by a motor (18). (20) is a brake roller, (22)
is a brake, and these brake rollers (20) and brakes (22) set tension on the wire electrode (lO) in the processing area. (24) is a pretension motor that applies a reverse torque to the bobbin (12) at the time of starting, thereby applying pretension to the wire electrode (10). (26) is a workpiece, which is machined into a desired shape by generating electric discharge between it and the wire electrode (10) by a power source (27). (2g
), (29) is a wire guide, and the workpiece (2B)
Guide the wire electrode (10) above and below. (30),
(32) is a nozzle that injects machining liquid to the machining portion of the workpiece (2B), and (50) is a tension suppressing means for suppressing tension fluctuations in the wire electrode (10).

FIG. 5 is an explanatory diagram of the structure of the tension suppressing means (50) in FIG. 4.

In FIG. 5, (52) is a pulley, (54) is a pulley shaft, (5B) is an arm, and (58) is a fixed arm shaft.

A wire electrode (10) is suspended from the pulley (52) and rotates together with the arm (56) about the arm shaft (58).

(60) is a pneumatic or hydraulic damper whose one end is connected to the shaft (66) of the arm (56) and the other end is fixed to a casing or the like;
(62) is a tension spring whose one end is connected to the shaft (64) of the arm (56) and whose other end is fixed to the casing or the like.

Figures 6 and 7 i are structural explanatory diagrams of another example of the conventional tension suppressing means (50), in which (67) in Figure 6 is an arm, which is supported by a ball bearing on the guide (B8) and slides along it. move up and down. Also in this case, as in FIG. 5, a rotating pulley (52) is attached to one side of the arm (67), and a damper (60) and an expansion spring (62) are provided to the other side. Also,
In FIG. 7, (60) is a rotary damper, and (82) is a helical spring.

The operation of the conventional wire electric discharge machining apparatus configured as described above will be explained as follows.

When the motor (18) of the wire collection means (16) is driven, the wire electrode (lO) is paid out from the bobbin (12). The wire electrode (10) that has been fed out is connected to the tension suppressing means (50), the idler (14a), the brake roller (
20), idler (14e) and upper die guide (2
8), it is supplied to the machining section of the workpiece (26) and electrical discharge machining is performed. The processed wire electrode (10) passes through the lower die guide (29) and the idler (14d), and is discharged out of the apparatus and recovered by the wire recovery means (16).

In this case, the motor (18) of the wire collection means (16) is controlled and the wire electrode (lO) runs at a constant speed, but the rotation of the bobbin (12) stops microscopically due to inertia. And the tension fluctuates due to intermittent rotation due to repeated over-rotation.

Now, when a change in the tension of the wire electrode (10) between the bobbin (12) and the idler (14a) occurs, the fifth to seventh
The pulley (52) shown in the figure moves up and down depending on the strength of the tension on the wire electrode (10). Due to the displacement of the arm (56) about its fulcrum as the pulley (52) moves up and down, the tension of the wire electrode (10) is reduced by the damping action caused by the movement of the piston in the damper (60) and the elasticity of the spring (62). fluctuations are suppressed.

[Problem to be solved by the invention] In the conventional wire electrical discharge machining device, mechanical tension suppressing means (50) using springs, air, hydraulic dampers (60), etc.
0) was used. For this reason, the wire electrode (10)
If the tension fluctuations are repeated continuously, the spring, the sliding part of the piston in the damper, the bearing of the arm, etc. will wear out and the suppressing function will deteriorate. When the ability to suppress tension fluctuations of the wire electrode (lO) deteriorates, the tension of the wire electrode (10) during machining is affected, and the accuracy of electrical discharge machining deteriorates.

In particular, if the vibration of the wire electrode (lO) and the boob etc. causes a resonance phenomenon due to tension fluctuations, the tension increases and the wire electrode (10) during processing breaks, reducing the operating rate of the equipment. There was a problem.

This invention was made to solve the above-mentioned problems, and it is possible to stabilize the wire electrode (10) over a long period of time by providing a tension suppressing means with a simple structure and almost no deterioration due to aging. The object of the present invention is to obtain a wire electrical discharge machining device that can be run.

[Means for Solving the Problems] A wire electrical discharge machining apparatus according to the present invention includes a half-half, which is held by a holding means and surrounds the wire electrode, in the middle of the traveling path of the wire electrode, which runs while being given a certain tension. A tension suppressing means made of a solid viscous material is provided.

[Function] Microscopic tension fluctuations applied to the wire electrode while being unwound due to the inertial force of the rotating bobbin are suppressed by the frictional force acting between the semi-solid viscous bodies and the deformation of the viscous bodies. be done. Then, the wire electrode travels stably in the processing area and the tension is kept constant.

Embodiment of the Invention FIG. 1 is an explanatory diagram of the configuration of a wire electrical discharge machining apparatus according to an embodiment of the present invention, and (■0) to (32) have the same structure and function as in FIG. 4.

In FIG. 1, (70) is a tension suppressing means according to the present invention, which is provided between the bobbin (2) and the idler (14a). The construction of the tension restraining means (70) is shown in FIGS. 2'(a) and (b).

In FIG. 2, (71) is a fixture having a mounting hole (74) drilled in the fixing surface, and (73) is a holding cylinder integrated with the fixture (71). There are insertion holes (72) on both sides of the holding tube (73).
), and a slit (75) for inserting the wire electrode (10) in the axial direction is provided on the outer periphery.

(76) is a viscous substance filled inside the holding cylinder (73). The holding tube (73) filled with the viscous material (76) is fixed to a housing or the like using the attachment hole (74) of the fixture (71). As the viscous material (76), a semi-solid material whose viscosity changes very little over time, such as fluorine or silicone grease, is used. Then, the wire 1 hypopole (10) is inserted into the holding cylinder (73) through the slit (75), and the central part (77) of the viscous body (76) is selected so as to match the traveling route. ing.

In the wire electrical discharge machining apparatus of the present invention having such a configuration, when the motor (18) is driven, the wire electrode (lO) is paid out from the bobbin (12) and the brake roller (20
), the workpiece (26), etc., and then the wire recovery means (16).
will be collected.

The wire electrode (10) in the running path immediately after being unwound from the bobbin (12) undergoes continuous minute fluctuations in tension based on the inertia of the rotation of the bobbin (12), as described above.

That is, due to the inertial force of the bobbin (12), the wire electrode (
10) When the amount of payout is greater than the steady traveling amount, the tension decreases. Conversely, when less wire electrodes (10) are paid out, the tension increases, and this variation in tension is repeated continuously.

In this way, the wire electrode (10
) is running surrounded by a viscous body (7G) within the holding cylinder (73) of the tension suppressing means (70). Therefore, on the one hand, a drag force corresponding to the vibration acts in the radial direction of the wire electrode (10) due to the viscosity of the viscous body (7B) and the friction of the contact surface. Furthermore, as the wire electrode (10) travels, a drag force in the counter-travel direction corresponding to the magnitude of the travel speed also acts.

As a result, fluctuations in tension that occur immediately after the wire electrode (10) is fed out are suppressed, and the wire electrode (lO) after the pulley (52) can be run stably.

Further, since the running of the wire electrode (10) near the processing area is not affected, processing can be performed while maintaining the tension at a constant value.

FIG. 3 is an explanatory diagram of the operation obtained as a result of experimentally measuring the suppressed state of tension fluctuation of the wire electrode (10) described above under the same conditions. FIG. 3(a) shows the actual measurement results of the conventional device, and FIG. 3(b) shows the actual measurement results of the device according to the present invention. As is clear from the figure, the period of tension fluctuation is approximately 2 SEC in both figures (a) and (b). Further, it is shown that while the fluctuation value of tension is about 80 g in the conventional device, it can be reduced to about 8 g in the device equipped with the tension suppressing means according to the present invention.

In addition, in the above-mentioned embodiment, a case has been described in which one tension suppressing means is placed near the bobbin to suppress fluctuations in the tension of the wire electrode immediately after being fed out, but it may be moved to another location or another device is placed. In other words, a plurality of electrodes may be arranged as long as the wire electrodes are in the middle of the travel route of the wire electrode. Further, the viscous body may be composed of a semi-solid substance whose main component is an animal, vegetable or mineral substance. moreover,
Although the case where the viscous material is semi-solid has been described, a semi-fluid viscous material can also be used as long as it does not flow from inside the holding cylinder.

[Effects of the Invention] As described above, according to the present invention, minute fluctuations in the tension of the wire electrode caused by the inertial force accompanying the rotation of the bobbin can be suppressed.
The tension suppressing means was constructed by suppressing the tension by a semi-solid viscous material surrounding the running wire electrode. As a result, fluctuations in the gap between the workpiece and the wire electrode are always suppressed, so that highly accurate machining can be achieved with a simple and inexpensive suppressing means. Furthermore, since the tension fluctuation value of the wire electrode can be reduced compared to conventional devices, there is no fear of the wire electrode being cut during machining, and there is an effect that a wire electric discharge machining device with a high operating rate can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of a wire electrical discharge machining apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the tension suppressing means in FIG. 1.
is a front view, (b) is a sectional view taken along line A-A in (a), and Fig. 3 (a) is a front view.
), (b) is an explanatory diagram of the operation of the present invention in comparison with a conventional device, FIG. 4 is an explanatory diagram of the configuration of a conventional wire electric discharge machining device, and FIGS. 5 to 7 are explanatory diagrams of the configuration of a conventional tension suppressing means. It is. In the figure, (10) is a wire electrode, (12) is a bobbin, (16) is a wire collection means, (26) is a workpiece, (
27) is a power supply, (30) and (32) are nozzles, (70)
) is a tension suppressing means, (71) is a support member, and (7B) is a viscous body. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] A bobbin around which a wire electrode is wound, a wire collection means for running and collecting the wire electrode fed out from the bobbin at a constant speed, a tension setting means for applying tension to the wire electrode, tension suppressing means for suppressing fluctuations in tension of a running wire electrode to which tension is applied by a tension setting means; and an electric discharge between a workpiece disposed in the middle of a running path of the wire electrode and the wire electrode. A wire electrical discharge machining apparatus, comprising: a power source for applying a voltage; and wherein the tension suppressing means is comprised of a substantially semi-solid viscous body held by a holding member and surrounding the wire electrode.