JPH11254239A - Wire-electric discharge machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize the thermal displacement of a lower arm, which is caused by changes in ambient temperature, and the relative displacement between an upper wire guide and a lower wire guide. SOLUTION: A cylindrical hollow section 27 is formed in a peripheral wall section comprising the outer periphery of a lower arm 13 in which a lower wire guide 14 is provided, and air is sealed in the hollow section 27. When temperature increases in the machining liquid 9 during electric discharge machining, the temperature of the outer periphery of the lower arm contacting the machining liquid 9 also increases, but because heat transmission is cut off by the layer of the air 28 in the peripheral wall section of the lower arm 13, the temperature of the whole of the lower arm 13 is hard to increase, restricting thermal displacement. For this reason, the relative displacement between an upper wire guide and the lower wire guide is minimized, preventing the lowering of machining accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire electric discharge machine having a lower arm provided with a lower wire guide.

[0002]

SUMMARY OF THE INVENTION A wire electric discharge machine is
As the wire electrode, a metal wire having a circular cross section and a diameter of 0.3 mm or less is used. Machining power is supplied to the wire electrode in the electric discharge machining part, and electric discharge is performed through a minute gap between the wire electrode and the metal work, thereby melting and removing the material of the work. Progresses.

In this type of wire electric discharge machine, usually, a wire guide for slidably positioning a wire electrode is disposed so as to face up and down with a workpiece interposed therebetween.
For this reason, generally, the upper wire guide located above the workpiece is provided on the upper part of the wire electric discharge machine body,
The lower wire guide located below the workpiece is provided at the distal end of a lower arm provided so as to project horizontally in the lower portion of the main body of the wire electric discharge machine.

By the way, in the conventional configuration, the lower arm is made of an integrated metal such as stainless steel. For this reason, for example, when the wire electric discharge machine is used in an environment inferior to the air conditioning equipment, or when the lower arm is used in a state where the lower arm is inserted into the machining fluid, the lower arm expands or expands under the influence of the surrounding temperature. There is a problem that it is easily displaced due to shrinkage, and the position of the upper wire guide and the position of the lower wire guide are relatively displaced (displaced), thereby lowering the processing accuracy.

The present invention has been made in view of the above circumstances, and an object of the present invention is to minimize the displacement of a lower arm with respect to a change in ambient temperature, whereby the relative position of an upper wire guide and a lower wire guide is reduced. An object of the present invention is to provide a wire electric discharge machine capable of suppressing a large displacement as much as possible and preventing a decrease in machining accuracy as much as possible.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an upper wire guide provided on an upper portion of a main body for slidably positioning a wire electrode above a workpiece. A lower arm provided below the wire guide so as to protrude laterally from the main body, and a lower arm provided on the lower arm so as to face the upper wire guide from below, and In the wire electric discharge machine having a lower wire guide for slidably positioning the wire electrode, a space for forming a heat insulating layer is provided on an outer peripheral portion of the lower arm. .

According to the above-mentioned means, even if the temperature around the lower arm changes, the lower arm is less likely to be displaced due to the heat insulating effect of the heat insulating layer on the outer peripheral portion. Can be suppressed as much as possible.

In this case, it is preferable that a fluid having a low thermal conductivity is sealed in the space where the heat insulating layer is formed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. First, in FIG. 1 showing a schematic configuration of the entire wire electric discharge machine, a main body 1 of the wire electric discharge machine is composed of a base 2 and a column 3, and a control device 4 is provided on the left side of the column 3 in the drawing. Is provided. A projecting portion 3a projecting horizontally is integrally provided on the upper portion of the column 3, and a Z-axis support base 5 is fixedly provided at a tip end of the projecting portion 3a.
An upper wire guide 6 is provided below the Z-axis support base 5 so as to be movable in the Z-axis direction (vertical direction in the figure). Below the upper wire guide 6, an upper nozzle 7 is provided. I have.

A table 8 is provided on the base 2 so as to be movable in two axes (X axis and Y axis) orthogonal to a horizontal plane orthogonal to the Z axis. On this table 8, a processing tank 10 for storing a processing liquid 9 is installed.
The processing tank 10 is moved in the X-axis and Y-axis directions together with the table 8. As the working fluid 9, water is usually used. A work mount 11 is provided in a fixed state in the processing tank 10, and a work 12 is fixed on the work mount 11 so that the work 12 is processed in the working fluid 9. Has become.

At the lower part of the column 3, a lower arm 13 is provided so as to project in the horizontal direction while being located below the projecting part 3a. The distal end of the lower arm 13 penetrates the side wall of the processing bath 10 and protrudes into the processing bath 10, and a lower wire guide 14 is provided at the distal end. The lower wire guide 14 is provided below the workpiece 12 so as to face the upper wire guide 6 from below. Above the lower wire guide 14, a lower nozzle 15 is provided.
The processing tank 10 can move between the processing tank 10 and the lower arm 13 with respect to the lower arm 13, and the processing liquid 9
There is provided a seal structure that prevents leakage.

A supply reel 17 around which a wire electrode 16 is wound is provided at an upper portion of the column 3, and the wire electrode 16 is fed from the supply reel 17. Wire electrode 16 unreeled from supply reel 17
A tension of about 2 kg is applied to the brake roller 18 provided on the overhang portion 3a. The tensioned wire electrode 16 is hung between a guide roller 19 provided on the Z-axis support base 5 and a guide roller 20 provided below the lower wire guide 14. Between 19 and 20, the upper wire guide 6
Upper nozzle 7 and lower nozzle 1 of lower wire guide 14
5, the upper nozzle 7 and the lower nozzle 1
5 slidably positioned. Upper nozzle 7
An electric discharge machining part 21 is provided between the upper part and the lower nozzle 15.

The wire electrode 16 applied to the lower guide roller 20 is passed through a wire electrode running path 22 (see FIG. 1) provided in the lower arm 13 and then provided on the lower portion of the column 3. It passes through the rollers 23 and is sent to the cutting machine 24. A drive roller (not shown) is provided in the cutting machine 24, and the supply reel 17 is rotated based on the wire electrode 16 being pulled by the drive roller,
Accordingly, new wire electrodes 16 are sequentially fed from the supply reel 17. Wire electrode 1 sent to cutting machine 24
6 is finely cut by a cutting blade provided in a cutting machine 24 and collected in a wire collection container 26 as wire cut pieces 25.

As shown in FIG. 1, the lower arm 13 has the wire electrode running path 22 extending in the axial direction at the center thereof, and has a cylindrical shape as a whole. It is fixed to. In this case, the lower arm 13 is formed of stainless steel having excellent corrosion resistance. A space portion 27 for forming a heat insulating layer is formed in a cylindrical shape on a peripheral wall portion which is an outer peripheral portion of the lower arm 13, and the peripheral wall portion has a hollow shape. In the space 27, a fluid having a low thermal conductivity, in this case, air 2
8 is enclosed.

In the above configuration, when electric discharge occurs between the wire electrode 16 and the workpiece 12 in the electric discharge machining section 21 during machining, heat is simultaneously generated, and the machining fluid stored in the machining tank 10 by the heat is generated. The temperature of 9 rises. When the temperature of the working fluid 9 rises, the temperature of the outer peripheral surface of the lower arm 13 that is in contact with the working fluid 9 also rises. In this case, a space 27 in which the air 28 is sealed is formed in the peripheral wall of the lower arm 13 and is insulated by the layer of the air 28, so that the temperature of the lower arm 13 as a whole hardly rises. For this reason, the lower arm 13 is hardly displaced, and the relative displacement between the upper wire guide 6 and the lower wire guide 14 can be suppressed as much as possible. It can be prevented as much as possible.

FIG. 3 shows a second embodiment of the present invention. The second embodiment differs from the first embodiment in the following points. That is, the water 30 is sealed as a fluid in the space 27 of the lower arm 13.
The fluid circulation path 31 is connected to the space 27,
The water 30 sealed in the space 27 is
And can be circulated through the A temperature adjusting section 32 constituting a temperature adjusting means is provided at an intermediate portion of the fluid circulation path 31, and the temperature adjusting section 32 is provided with a fan device 33.
Is provided.

In the above configuration, when the temperature of the machining fluid 9 rises due to electric discharge machining, heat is transmitted to the outer peripheral portion of the lower arm 13 which is in contact with the machining fluid 9, but the heat is transmitted to the space 27.
It is robbed by the water 30 enclosed therein. The water whose temperature has risen due to the deprivation of heat flows through the one passage 31a of the fluid circulation path 31 to the temperature adjusting section 32 side, where it is cooled by the wind of the fan device 33 and emits heat. Cooled water 30
Returns to the space 27 through the other passage 31b. By repeating such operations continuously, the temperature of the lower arm 13 as a whole hardly rises. Therefore,
Also in this embodiment, the water 3 sealed in the space 27 is used.
0 acts as a heat insulating layer. Therefore, similarly to the first embodiment, the lower arm 13 is hardly displaced even when the ambient temperature changes, and the relative displacement between the upper wire guide 6 and the lower wire guide 14 is suppressed as much as possible. Therefore, even if the processing proceeds, it is possible to prevent the processing accuracy from lowering as much as possible.

FIG. 4 shows a third embodiment of the present invention. The third embodiment differs from the first embodiment in the following points. That is, the lower arm 35 has a cylindrical arm main body 36 having the wire electrode running path 22 extending in the axial direction at the center thereof, an outer peripheral surface of the arm main body 36 being covered from the outside, and And a cylindrical member 39 provided so as to form a heat insulating space 38 via a seal member 37 therebetween. Space 38
Has a cylindrical shape, in which air 28 is sealed as in the first embodiment. In this case, the arm body 36
The tubular member 39 is made of stainless steel, and the seal member 37 is made of elastic rubber which hardly conducts heat.

In the case of the third embodiment having such a structure, the following advantages can be obtained in addition to the same effects as those of the first embodiment. That is, since the lower arm 35 is composed of two members, the arm main body 36 and the outer cylindrical member 39, the space 38 between them is provided.
Can be easily formed. Thus, the lower arm 35 having the heat insulating space 38 can be manufactured at low cost. Further, the material of the arm body 36 and the material of the outer cylindrical member 39 can be made different.

The present invention is not limited to the above embodiments, but can be modified or expanded as follows. In each of the above embodiments, the electric discharge machining is performed in the machining tank 1.
Although the configuration in which the processing is performed in the processing liquid 9 stored in 0 is illustrated, the present invention can be applied to a configuration in which the processing tank 10 is not used.

Further, in each of the above-described embodiments, the structure in which the workpiece 12 as the workpiece is moved with respect to the upper wire guide 6 and the lower wire guide 14 is exemplified. The present invention can also be applied to a configuration in which the upper wire guide 6 and the lower wire guide 14 move relative to the workpiece 12 with the 12 side fixed.

The space 27, 38 may be filled with a liquid such as oil 28 or glycerin having a low thermal conductivity, or a gas such as sodium, freon (refrigerant gas), ammonia, etc., in addition to the air 28 and water 30. Liquid or gas such as inert gas such as nitrogen or argon,
Alternatively, a foamed heat insulating material (solid) having a low thermal conductivity such as polystyrene can be used. In addition, the space portions 27 and 3
8 may be evacuated or reduced to atmospheric pressure or lower.

[0023]

As is clear from the above description, according to the present invention, the following effects can be obtained. Claim 1
According to the wire electric discharge machine, even when the temperature around the lower arm changes, the lower arm is less likely to be displaced due to the heat insulating effect of the heat insulating layer on the outer peripheral portion, and thereby the upper wire guide and the lower wire guide Relative displacement can be suppressed as much as possible, and as a result, reduction in processing accuracy can be prevented as much as possible.

According to the wire electric discharge machine of the second and third aspects, the displacement of the lower arm in response to a temperature change can be more favorably prevented. According to the wire electric discharge machine of the fourth aspect, since the lower arm is composed of the arm body and the outer cylindrical member, a space can be easily formed between them. Therefore, the lower arm having the heat insulating space can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view of a main part showing a first embodiment of the present invention.

FIG. 2 is an overall front view showing a partly broken portion;

FIG. 3 is a view corresponding to FIG. 1, showing a second embodiment of the present invention.

FIG. 4 is a view corresponding to FIG. 1, showing a third embodiment of the present invention;

[Explanation of symbols]

1 is a main body, 2 is a base, 3 is a column, 6 is an upper wire guide, 8 is a table, 9 is a processing liquid, 10 is a processing tank, 12 is a workpiece, 13 is a lower arm, 14 is a lower wire guide,
16 is a wire electrode, 21 is an electric discharge machining part, 22 is a wire electrode running path, 27 is a space part, 28 is air (fluid), 30 is water (fluid), 31 is a fluid circulation path, and 32 is a temperature adjusting part (temperature). Adjusting means), 33 is a fan device, 35 is a lower arm,
36 denotes an arm body, 37 denotes a seal member, 38 denotes a space, and 39 denotes a cylindrical member.

Claims (4)

[Claims] 1. An upper wire guide provided on an upper part of a main body for slidably positioning a wire electrode above a workpiece, and positioned below the upper wire guide to project laterally to the main body. A lower arm provided on the lower arm so as to face the upper wire guide from below, and a lower wire guide slidably positioning the wire electrode below the workpiece. In the wire electric discharge machine, a space for forming a heat insulating layer is provided on an outer peripheral portion of the lower arm. 2. The wire electric discharge machine according to claim 1, wherein a fluid having a low thermal conductivity is sealed in the space. 3. A method according to claim 1, wherein a fluid is sealed in the space, a fluid circulation path through which the fluid sealed in the space circulates is connected, and temperature adjusting means is provided in the fluid circulation path. Item 7. A wire electric discharge machine according to item 1. 4. A lower arm includes: an arm body; and a space for covering an outer peripheral surface of the arm body from outside and forming a heat insulating layer between the arm body and the arm body via a seal member. 2. A wire electric discharge machine according to claim 1, wherein said wire electric discharge machine comprises: