JPH0271931A - Electric discharging machine for wire cutting - Google Patents

Abstract

PURPOSE:To reduce friction resistances of a wire electrode and die type guide, to travel the wire electrode with good stability and to prevent disconnection, etc., by increasing the inner diameter of a die type wire electrode guide in 10-20m more than the outer diameter of a used wire electrode. CONSTITUTION:The difference in the outer diameter of a wire electrode 4 and that of a die type guide 3, namely the clearance is taken in 10-20mum. As a result, even in case of a taper angle being large, the wire electrode 4 being brought into contact with the die type guide 3 at two points is eliminated and the friction resistance of the wire electrode 4 and die type guide 3 is reduced. So the wire electrode 4 travels with good stability and no disconnection, etc., are generated, and yet mean work current is stabilized as well, no nick, etc., are generated on the work face and a smooth work face can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in wire cant electrical discharge machines. In particular, the present invention relates to an improvement that facilitates taper processing.

More specifically, the wire electrode guide is easy to manufacture, there is no need to control the Taber angle of Taber processing or correction of V-axis control, and wire breakage does not occur even at large Taber angles. The present invention relates to an improvement that enables electric discharge machining to be performed with a stable average machining current and to realize a smooth machined surface without creating streaks on the machined surface.

[Conventional technology]

The schematic structure of a wire-cut electrical discharge machine according to the prior art will be explained with reference to FIG. 2. In FIG. 16 in a plane. Reference numeral 12 denotes a column, which, as shown, consists of a pillar part and an arm part. An arm 13 is supported by the column 12, extends through the processing liquid tank 14 to the processing area, and supports the lower wire electrode guide 17. The wire electrode i21 is stretched between the lower wire electrode guide 17 and the upper wire electrode guide 20 supported by the U--axis moving device 19 supported by the Z-axis 18 supported by the column 12. , the U-■ axis moving device 19, that is, the upper wire electrode guide 20 is movable up and down (22 is an elastic cover such as a bellows),
The UV axis moving device 19 moves the upper wire electrode guide 20 in a horizontal plane, thereby tilting the wire electrode 21 and enabling taper processing.

If it is not necessary to perform taber processing, various types of guides such as groove-type guides, arc-type guides, die-type guides, etc. can be used as the upper and lower wire N oak guides, but if it is necessary to perform taber processing. As shown in FIG. 3, conventionally, a die-shaped guide 23 and an arc-shaped guide 2. With i (■
combination was used. When such a combination wire electrode guide is used, when the wire electrode 21 is vertical, it is guided by the die-shaped guide l''23, but when the wire electrode 21 is tilted large, it is guided by the arc-shaped guide 24. This is because even if the Taber angle becomes large, the wire electrode 21 will not come into contact with the die-shaped guide 23 at two points, and the wire electrode 21 will run stably.

Note that a wire with a wire diameter of 0□2 to 0.3 mm is used for the wire electrode 21, and the allowable minimum radius of curvature of the arc-shaped guide 24 corresponds to each wire diameter of the wire electrode 21.
They are selected as shown in the table below.

Table 1 Relationship between the wire electrode diameter and the minimum radius of curvature of the arc-shaped guide Wire electrode diameter Minimum radius of curvature of the arc-shaped guide - 4, - 0.2 0.3 Also, for any wire electrode guide , the inner diameter of the wire electrode guide needs to be somewhat larger than the scratch of the wire electrode, but the difference (hereinafter referred to as clearance)
) was conventionally set at 5 to 10 fl.

[Problems to be Solved by the Invention] A wire cutter electric discharge machine using a wire electrode guide of the above-described combination of a die-shaped guide and an arc-shaped guide has the following drawbacks.

(1) It is difficult to accurately form the curvature accuracy of the arc-shaped guide.

It is difficult to arrange the zero arc type guide and the die type guide concentrically.

C. As the Taber angle increases, the contact point between the wire electrode and the arcuate guide changes, so the reference point for U-■ axis control changes, requiring correction of the tJ-V axis control program, which burdens the software. increases.

The purpose of the present invention is to eliminate this drawback, and to provide a wire-cut electric discharge machine in which the manufacture of a wire electrode guide is easy, there is no need to correct the U-■ axis control program, and the burden on software is light. There is a particular thing.

[Means to solve the problem]

The above purpose is to adjust the inner diameter of the die-type wire electrode guide (3) to the wire electric FIi (
This is achieved by making the outer diameter 10 to 20u larger than the outer diameter of 4).

Further, in addition to the above, if the tensile strength of the wire electrode (4) is set to 42 to 46 kg/wa'' and a soft wire electrode (4) is used, the above effect is further improved.

[Effect]

The wire-cut electrical discharge machine according to claim 1 of the present invention uses only the die-shaped guide 3, and moreover, the difference between the outer diameter of the wire electrode 4 used and the outer diameter of the die-shaped guide 3, that is, the clearance is the conventional 5 to 10. n to 10~
Since the diameter is significantly large at 2On, even if the Taber angle is large, the wire electrode 4 will not come into contact with the die-shaped guide 3 at two points, and the frictional resistance between the wire electrode 4 and the die-shaped guide 3 will be reduced. Because of its small size, the wire electrode 4 is fed stably and wire breakage does not occur, and for the same reason as above, the average machining 1t1 is stable2, and no streaks or the like occur on the machined surface. A smooth machined surface can be formed. Furthermore, since only the die-shaped guide 3 is used, manufacturing of the wire electrode guide is easy, and as mentioned above, the wire electrode 4 is attached to the die-shaped guide 3.
Since there is no point contact, there is no need to correct the UV axis control program (and the burden on the software is reduced).

Furthermore, in the wire-cut electric discharge machine according to claim 2 of the present invention, in addition to the above, a soft wire T8i4 is used (the tensile strength of the conventionally used wire electrode 4 is 60 to 70 kg/ ai'', but the tensile strength of the wire IHBi 23 used in claim 2 of the present invention is 42 to 46 kg/ms''), so the above effect is further enhanced.

The outer diameters are 0.2mm and 0.25ai11.
Experiments were repeated with different clearances for the wire electrode 23 of 0.3 mm, and the maximum allowable taper angle at which sufficiently satisfactory machining characteristics were achieved is shown below.

Table 2 Relationship between allowable maximum taper angle and clearance (n) with respect to outer diameter (m) of various wire electrodes JJ L2. I n Clearance 0~51510 111 YuyuL 8~1220 15 513
~1725 20 10 [Example] Hereinafter, a wire electrode guide used in a wire-cut electric discharge machine according to an example of the present invention will be described with reference to the drawings.

Referring to FIG. 1, reference numeral 3 denotes a die-shaped wire electrode, the inner diameter of which is lθ~20n larger than the outer diameter of the wire electrode 4 used. In other words, the outer diameter of the wire electric 8i4 is 0.
．． 0.210~0.220on for 2m, wire 1
! When the outer diameter of 8i4 is 0.25m, it is 0.260~0.
270 m, and when the outer diameter of the wire electrode 4 is 0.3 mm, it is 0.310 to 0.320 m.

31 is a jig with a taper of about 35 degrees from the center.

Moreover, the tensile strength of the wire electrode 4 used is 42 to 4
6 kg/m".

When using a wire electrode guide with the above combination, the average machining voltage will not fluctuate and will remain stable up to the taper angle described in the [Operation] section, and no streaks will occur on the machined surface.
Moreover, the wire electrode 4 does not come into contact with the die-shaped guide 3 at two points, and the wire electrode 4 and the die-shaped guide 3
Frictional resistance is small, and there is no risk of wire breakage.

〔Effect of the invention〕

As explained above, the wire-cut electric discharge machine according to the present invention is a wire-cut electric discharge machine having a die-type wire electrode guide, and the inner diameter of the die-type wire electrode guide is 10 to In addition to the above, the tensile strength of the wire electrode is said to be 42 to 46 kg/am'', and the wire electrode is soft, so even when the taper angle is large, the wire electrode can be easily diced. There is no contact with the mold guide at two points, the frictional resistance between the wire electrode and the die mold guide is small, the wire electrode is fed stably, and wire breakage does not occur, and for the above reasons, processing is easy. It is possible to form a smooth machined surface without creating streaks on the surface.

As a result, (a) arc-shaped guides that are difficult to form with accurate curvature accuracy are not used, and there is no need for concentric arrangement, making it easier to manufacture wire electrode guides, and (b) reducing the Taber angle. Since the contact point between the wire electrode and the arcuate guide does not change as Effects such as no increase in burden can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of a wire t17ii guide used in a wire-cut electrical discharge machine according to an embodiment of the invention. FIG. 2 is a schematic structural diagram of a wire cant electrical discharge machine according to the prior art. FIG. 3 is a structural diagram of a conventional wire electric bridge guide using a plowing method using a die-shaped guide and an arc-shaped guide. 19・ ・ 20・ ・ 21・ ・ 22・ ・ 23・ ・ 24・ ・ 31・ ・ ・UV axis moving device, ・Upper wire electric bridge guide, ・Wire electrode, ・Stretchable cover such as bellows, dice type guide,・Arc-shaped guide, ・Jig.

Claims (1)

[Claims] [1] In a wire-cut electric discharge machine having a die-shaped wire electrode guide (3), the inner diameter of the die-shaped wire electrode guide (3) is larger than the outer diameter of the wire electrode (4) used. A wire-cut electric discharge machine characterized by being 10 to 20 μm larger. [2] The tensile strength of the wire electrode (4) is 42 to 46
The wire-cut electric discharge machine according to claim 1, wherein the wire-cut electric discharge machine has a cutting speed of 1 kg/mm^2.