JPH01146620A - Wire electric discharge machining device - Google Patents

Abstract

PURPOSE:To prevent production of the fluctuation in tension and the fluctuation in amplitude of a wire electrode due to the unbalanced load of a wire bobbin, by providing a brake means which exerts a brake force on a rotary shaft to support a wire bobbin and can regulate the brake force. CONSTITUTION:A wire electrode 10 is consumed by machining, and as the winding size of a wire bobbin 12 secured on a mounting shaft 30 is decreased, the number of revolutions is increased, and the tension of the wire electrode 10 is also changed. In which case, the number of revolutions of the wire bobbin 12 is detected by means of the number of revolutions detecting means 78, a detecting signal therefrom is processed by a control means 600 so that a specified tension is generated. In order to obtain a proper brake factor responding to the rotation speed of the wire bobbin 12, a pulse motor 68 is run to vary and control a gap between a rotary shaft 62 and a slide shaft 66, and through variation of the volume of locating viscous fluid 60, the tension of the wire electrode 10 is always kept at a specified value. This constitution produces a low surface coarseness freed from the generation of a longitudinal rib, and enables prevention of disconnection of the wire electrode due to amplitude vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wire electrical discharge machining apparatus for machining a workpiece into a desired shape using a wire electrode, and particularly to a mechanism for suppressing tension fluctuations in the wire electrode.

[Conventional technology]

FIG. 8 is a schematic diagram showing, for example, the path of a wire electrode in a conventional wire electric discharge machining device.

In the figure, αG is a wire electrode, (2) is a wire bobbin that winds the wire electrode, (14a) to (14dJ) are the first to fourth idlers that guide the huff ear electrode αG, and (to) is consumed in the machining gap. (1) is a wire collection motor that collects the wire electrode α0, (1) is directly connected to the wire collection motor (to) and is connected to a T-Kibustan roller; 12'D is a spring; A pinch roller is pressed against the wire; (c) is a brake roller that applies main tension to the wire electrode QQ; a wire is a brake that drives the brake roller cI4; and a second power supply unit,
(g) is the initial tension brake that applies initial tension to the wire electrode, ■ is the mounting shaft that supports the wire bobbin, (to) is the workpiece, (to) is the machining wL oil device, (to) and (to) are Upper and lower wire guides (g) and (6) for guiding the wire electrode αO at the upper and lower parts of the workpiece are upper and lower nozzles that eject machining liquid into the machining gap.

In addition, (9) is a wire collection mechanism part, and the code|symbol (to) and 翰.

The wire electrode αO is configured by the wires υ, e; 2 and is used to run the wire electrode αO at a desired speed.

Also, +2007 is the wire bobbin attachment part and is coded (2).
.

It is composed of kan and ■.

Next, the operation will be explained. The wire electrode αO is unwound from the wire bobbin@, and the first idler (141Ll-
Brake roller (c) → second idler + 14b)
- 3rd idler + 14 ri - 1st power supply section - Upper wire guide C〃→Workpiece C◇ - Lower wire guide gloss → 2nd power supply section (7a) → 4th idler (14d) - Wire It is stretched along the path of the collection mechanism section (9).

Then, the wire collection motor (
) is operated, the pinch roller (1) and the pinch roller (H) rotate, and the pinch roller (E) is rotated.
and one wire electrode αO held between pinch rollers (A).
The wire electrode αO is continuously fed from the wire bobbin, is consumed by electric discharge in the machining gap, and is collected in a collection box (not shown).

Next, the first and second power supply parts (
), the machining voltage is applied to the wire electrode α via t27a)
O is supplied to the workpiece (to) to generate an electric discharge, and the X-Y table attached to the workpiece (not shown) operates to move the workpiece to the desired position. It is cut into the shape of.

Note that a brake (
C) and the initial tension brake (to) are each set to 1.
The tension added to this value is acting.

Here, if there is an unbalanced load on the wire bobbin (■), the initial tension brake (■) generates a constant braking force, so the position of the unbalanced load moves as the wire bobbin (■) rotates, so the above speed increases. Thickness warping occurs in the wire bobbin, which is stretched between the wire bobbin side and the wire recovery mechanism section (9) and appears as a tension fluctuation in the wire electrode αq.

Further, as the wire electrode αO wound around the wire bobbin (6) is fed, the winding diameter of the wire bobbin @ decreases, and accordingly, the rotation speed of the wire bobbin @ increases and the wire bobbin αG increases. Tension changes.

[Problem that the invention attempts to solve]

Conventional wire electrical discharge machining equipment is configured as described above, so even if the wire collection motor rotates at a constant speed and winds up the wire electrode, the angular velocity of the wire bobbin will change due to the unbalanced load on the wire bobbin. It becomes large when rotating from above to below, and conversely becomes small when rotating from below to above.

Therefore, due to this change in angular velocity, tension fluctuation occurs in the single wire electrode stretched between the wire bobbin and the wire collection mechanism section. This tension fluctuation causes a change in the amplitude of the wire electrode in the machining gap, which causes a decrease in machining accuracy and a decrease in surface roughness quality on the machined surface due to the generation of vertical streaks, which increases the efficiency of wire electrical discharge machining equipment. It doesn't hinder precision.

In addition, if the tension fluctuation of the wire electrode is abnormally large, a wire breakage occurs, resulting in a decrease in the operating rate of the wire electrical discharge machining machine. As the winding diameter decreases due to consumption of wire l11., the rotational speed increases. One problem is that the tension on the pole changes, resulting in inconsistent machined surface quality between the beginning of processing and the processing line.

This invention was made to solve the above problems.
The object of the present invention is to provide a wire electric discharge machining device which has high machining accuracy and a high operating rate by eliminating tension fluctuations in a wire electrode and applying an appropriate tension corresponding to the number of rotations of a wire bobbin.

[First Means for Solving the Problems] The wire electrical discharge machining apparatus according to the present invention has a mounting portion for supporting a wire bobbin, and has a rotating shaft and a braking force adjusting means for controlling the braking means. The means drives and controls the braking force adjusting means, the rotational speed of the rotary shaft is detected by the rotational speed detecting means, and the detected signal is inputted to the control means.

[Effect]

In this invention, the braking force node means engaged with the sliding wheel slides on the sliding shaft, and connects the rotating shaft in the viscous fluid to the opposing distance of the sliding shaft. It applies a braking force to the vehicle and adjusts the braking force. .

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. The present invention has the same structure as the conventional device shown in FIG. 3, except that the wire bobbin mounting portion is used as a braking means. In FIG. 1, the ring fixes the wire bobbin o2 to the mounting shaft. Mounting nut, 53 is bearing, (b)
The inner ring side is fixed to the mounting axis ω and the outer [phase] is fixed to the housing which is fixed to the machine body.The mounting shaft (to) is supported rotatably with respect to the housing (to). The nut, ... is a viscous fluid (such as silicone oil) that is a damping material, the ring is a rotating shaft, the ring is a bearing, - is rotatably supported by a bearing shaft, and the rotating shaft is directly connected to the mounting shaft. The ring is rotated through a viscous fluid, and the sliding shaft is provided opposite the UN wheel. - A pulse motor that moves the sliding wheel back and forth without rotating it, t! ◆ and go are first and second O-rings that prevent viscous fluid from leaking to the outside; (
71194! A rotation speed detection device for detecting the rotation speed of the mounting axle group (500J is a braking force adjustment means consisting of a symbol -0).

Next, the operation will be explained. The wire electrode αG is unwound from the wire bobbin υ and is consumed due to the electrical discharge in the machining gap.
The wire feed route is then collected in an undisclosed collection box.
The process in which machining pressure is supplied from the machining electric smearing device (2) and the X-Y table (not shown) is operated to perform machining is the same as that of the conventional device, so a description thereof will be omitted.

Now, when feeding the wire electrode αO, the wire bobbin @
In this case, the braking means (200) operates as described below.

That is, as shown in FIG. 2(a), the wire bobbin (2)
The center of the mounting hole of the wire bobbin (
2) rotates to the left, and if the unbalanced load position of the wire bobbin (2) moves from above to below as shown in Fig. 2 (b), the mounting shaft - on which the wire bobbin υ is attached, Attached with a car puller, 1
As the angular velocity of this rotating shaft wheel tends to increase, the braking coefficient of the viscous fluid interposed in the gap between the rotating shaft and the sliding wheel increases, and the braking force on the rotating shaft increases, causing the angular velocity to decrease. Conversely, when the unbalanced load position moves from below to above as shown in FIG. 2 (0), the angular velocity tends to decrease, so the braking coefficient decreases [1. The braking force on the rotating shaft decreases,
It works to prevent the angular velocity from decreasing.

Therefore, the above-mentioned angular velocity variation per revolution of the wire bobbin υ becomes extremely low, and the tension variation ff1I+ of the wire electrode αO can be made extremely small.

Further, as the wire 'ethaa is consumed by processing and the winding diameter of the wire bobbin (2) becomes smaller, the number of revolutions of the wire bobbin @ gradually increases, the tension of the wire electrode αG also changes. Therefore, even if the rotational speed of the wire bobbin υ increases, it is necessary to change the braking coefficient of the braking means +2007 to an appropriate value in accordance with the rotational speed of the wire bobbin@ so that a constant tension can be obtained regardless of the rotational speed. be. In such a case, the rotation speed of the wire bobbin υ is detected by the rotation speed detector (e), and the detection signal is input to the control means t600) for processing, and then the wire bobbin (2
), the pulse motor is controlled by the output from the control means (600).
By automatically changing and controlling the gap between the rotating shaft and the sliding wheel, the amount of viscous fluid interposed between the rotating shaft and the sliding wheel is adjusted, and the wire electrode α
It is controlled so that the tension of O is always constant.

Furthermore, when changing the feeding speed or tension of the wire electrode OQ depending on processing conditions, the control means (6
By instructing the desired wire electrode αO feeding speed or tension to the control means (60), the command value is set to the control means (60).
After being processed in step 0), the output drives the pulse motor, and in the same manner as described above, it is possible to set and maintain an arbitrary tension value corresponding to the command value.

In addition, in the above embodiment, the liner bearing 4 holds t'
The 11th sliding shaft serves as a means for moving the sliding shaft back and forth without rotating it through O'0.

Although a pulse motor is used in this example, the same operation can be expected by using a DC servo motor with a position detector, an AC servo motor with a position detector, an air cylinder, or a hydraulic cylinder.

Furthermore, in the above embodiment, the tension of the wire fill αO is controlled to be always constant by adjusting the volume of the viscous fluid interposed between the rotating shaft and the sliding shaft. However, this is done by controlling the temperature of the viscous fluid...
A similar operation can be expected even if the braking coefficient is changed by changing the viscosity and the tension is always kept constant.

〔Effect of the invention〕

As described above, according to the present invention, the braking means is capable of applying a braking force to the rotating shaft that supports the wire bobbin and can adjust the braking force. Since this can be suppressed, a machined surface with low surface roughness without the occurrence of vertical streaks can be obtained, and wire electrode breakage due to amplitude fluctuation can also be prevented, and a high operating rate can be maintained. Furthermore, since the braking force of the braking means can be adjusted by the control means, the optimum braking force can be applied to the rotational speed of the wire bobbin or the set tension of the wire electrode, and a highly accurate device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a braking means according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing an unbalanced load on a wire bobbin, and FIG.
The figure is a schematic diagram showing a wire path of a conventional wire electric discharge machining device. αO is a wire electrode, ■ is a wire bobbin, flash is a housing, ... is a viscous fluid, □ is a rotation axis, a ring is a sliding axis, g pull rotation speed detection means, +200J is a braking means, <500) is a braking force adjustment means , +600) is a control means. In addition, the same reference numerals in the figures represent the same or equivalent parts.

Claims (1)

[Claims] A housing sealed with a viscous fluid, a rotating shaft having a mounting part for supporting a wire bobbin wound with a wire electrode on one side and a concave or convex part on the other side, a convex or concave part on one side and a rotating shaft on the other side. comprising a sliding shaft having an engaging portion, and a control force adjusting means provided on the housing and engaged with the engaging portion of the sliding shaft to slidably drive the sliding shaft, The rotating shaft and the sliding shaft are immersed in the viscous fluid with their recesses or protrusions closely facing each other, and the rotating shaft is rotatably supported in the housing, and the sliding shaft is slidably supported in the housing. A wire electrical discharge machining device comprising a braking means, a control means for driving and controlling the braking force adjusting means, and a rotation speed detection means for detecting the rotation speed of the rotating shaft and inputting it to the control means. Device.