JPS62157727A - Wire-cut electric discharge machining method - Google Patents

Abstract

PURPOSE:To easily exhaust chips and stabilize machining by passing a traveling wire electrode through a mold provided on the rear side of a workpiece with respect to the feed direction to mold it into a noncircular cross section and melt-machining the wire electrode while rotating it. CONSTITUTION:A wire electrode 1 is extracted from a feed reel 2 and travels at a fixed speed and is molded into a noncircular cross section from a circular cross section by molding rollers 8 and passes a workpiece 7 while being rotated in the positive direction and negative direction centering its axis by a rotary driving device 9 made of reciprocating rollers. A machining liquid is sprayed through a nozzle 11, the voltage is applied across an electrode 1' and the workpiece 7 serving as both poles, an electric discharge is generated, and the molten portion is scattered as chips. The workpiece 7 is moved by a table 6, and chips scattered at the gap section between the electrode 1' and machining section 12 are extracted via notch sections 24 of the electrode 1' to a wide space section on the opposite side to the machining side and are easily removed because the electrode 1' is being rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a wire-cut electrical discharge machining method for cutting a workpiece into a desired shape while causing electrical discharge between a traveling wire electrode and the workpiece. .

(Prior art and its problems) Generally, in wire-cut electrical discharge machining, while a wire electrode is running at a constant speed, the electric discharge between the wire electrode and the workpiece heats the machined part of the workpiece to a high temperature of several thousand degrees. The melted material is separated from the workpiece by the processing fluid, and is discharged and removed from the processing section, while cutting progresses. However, in this case, most of the fine chips that are separated from the workpiece and scattered by the machining fluid are discharged outside the workpiece, but some of the chips are trapped in the narrow gap between the wire electrode and the machined part. The chips tend to remain attached to the machined part without being discharged to the outside, and the remaining chips attached to the machined part undesirably narrow the gap between the wire electrode and the machined part, causing discharge failure. Furthermore, there was a problem in that a short circuit occurred between the two electrodes, making it impossible to discharge. Furthermore, the workpiece side is melted and removed by the electric discharge as described above, and the wire electrode side is also melted and consumed, although less than the workpiece side. However, since the wire electrode itself does not rotate, wear and tear on the wire electrode is concentrated on the side facing the machining part, and as a result, one side of the wire electrode, which normally has a circular cross section, is deeply gouged. This caused wire breakage and poor machining accuracy.

(Technical means for solving the problem) Therefore, the inventor of the present invention has found that the cutting chips can be easily discharged from the machining section by giving rotation to the running wire electrode, but also the cross-sectional shape of the wire electrode It has been found that chip removal can be effectively achieved by changing the conventional circular shape to a non-circular shape such as a triangular shape. Therefore, the technical means of the present invention is to form a running wire electrode into a non-circular cross-sectional shape by passing it through a mold provided on the rear side of the workpiece with respect to the feeding direction, and to rotate the running wire electrode. It is characterized by the fact that it performs fusing processing.

(Example) Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a wire-cut electric discharge machining apparatus for implementing the present invention. In this figure, reference numeral 1 denotes a wire electrode with a circular cross section that is supplied from a supply reel 2 on the upper side of the device, and after being guided vertically downward by upper and lower guide rollers 3 and 4, it is transferred to a take-up reel 5 on the lower side. However, immediately after passing through the upper guide roller 3, the forming roller 8
This makes it possible to form a non-circular cross-section. Note that the wire electrode after being formed into a non-circular cross section is shown at 1°. The wire electrode is driven by driving the take-up reel 5 with a motor (not shown), and by driving an intermediate drive roller (not shown) provided between the supply reel 2 and the take-up reel 5. done through.

Reference numeral 6 denotes an XY table for processing, which is movable on a horizontal plane in the X-axis and Y-axis directions, and a workpiece 7 is supported on this table 6. The forming roller 8 is provided on the rear side of the workpiece 7 in the feeding direction of the wire electrode, that is, between the upper guide roller 3 and the workpiece 7, and has a shape, for example, as shown in FIG. having/pair of rollers 8a, 8
By passing between these rollers 8a, 8a, the wire electrode 1, which has a circular cross section and is unwound from the supply reel 2, forms a wire electrode l having a cross section as shown in the figure.

becomes. Reference numeral 9 denotes a wire electrode rotation drive device provided on the front side of the workpiece 7 with respect to the feeding direction of the wire electrode, and as shown in FIG. Pair of drive rollers 10. By reciprocating the l pair of drive rollers 10°10 in opposite directions, the wire electrode 1 passing through the workpiece 7 can be rotated about its axis or rotated every multiple rotations. It is designed to rotate in the opposite direction. The rotation of the wire 14 by the rotary drive device 9 is performed in the range from the forming roller 8 to the front side of the lower guide roller 4. Reference numeral 11 denotes a machining fluid supply nozzle, which jets machining fluid from the upper part of the workpiece 7 toward the machining section 12, as shown in FIG.

In wire-cut electric discharge machining using the apparatus having the above-mentioned configuration, the wire electrode 1 is unwound from the supply reel 2 and runs at a constant speed, but the forming roller 8 changes the cross-sectional shape from a circular shape as shown in FIG. It is formed into a non-circular shape, and when it leaves the forming roller 8, it is rotated by a rotary drive device 9 and passes through the workpiece 7 while rotating around its axis. A machining fluid is jetted from the nozzle 11 toward the machining section 12, and a voltage is intermittently applied between the wire electrode 1' and the workpiece 7, with the wire electrode 1' and the workpiece 7 as polar poles, causing an electric discharge. As a result, the workpiece 12 is melted at a high temperature of several thousand degrees or more, and the melted portion becomes chips and scatters due to impact pressure caused by vaporization of the processing fluid. Note that the workpiece 7 is moved by the XY table 6 so that the wire electrode 1' moves relatively along the fusing line. Most of the chips scattered in this way are discharged and removed together with the flowing machining fluid and the traveling wire electrode 1'', but the chips scattered in the narrow gap between the wire electrode 1' and the machining section 12 are removed by the conventional method. However, in the present invention, since the wire electrode 11 rotates around its axis, the wire electrode 11 tends to stay in the narrow gap and remain attached to the processed part 12. Due to the rotating action of the wire electrode 1', the chips scattered in the area are successively dragged out by the wire electrode 1' into a wide space on the opposite side to the side where machining is currently being performed, and are discharged and removed. Moreover, in this case, the wire electrode 1° has a non-circular cross section with cutouts 24, 24 on both sides, so when the wire electrode 1' is rotated to pull out chips, the cutouts 24, etc. are removed. A scraping action is exerted through the electrode, and chips do not slip on the circumferential surface of the electrode unlike in the case of a circular cross section, so that chips can be discharged and removed more effectively.

In the electrical discharge machining apparatus shown in FIG. 1 described above, the rotational drive device 9 rotates a part of the wire electrode while moving it in the opposite direction, but in FIG. This figure shows an electric discharge machining apparatus equipped with a rotation drive device 13 for rotating the entire wire electrode. Note that this electric discharge machining apparatus is almost the same as the apparatus shown in FIG. 1 except for the rotary drive device 13, so corresponding members are indicated by the same numbers. That is, the rotational drive device 13 shown in FIG. 3 includes a pedestal 14 that supports the supply reel 2, the upper guide roller 3, the forming roller 8, etc., and the take-up reel 5, the lower guide roller 4, the intermediate guide roller 15, etc. The supporting frame 16 is supported rotatably around the axis l, while a rotary drive shaft 17 is provided parallel to the axis l, and fixed sprockets 18 and 19 are mounted on the rotary drive shaft 17. The sprockets 20 and 21 provided on the mounts 14 and 16 are connected by chains 22 and 23, respectively, and the rotational drive shaft 17 is driven to rotate the frames 14 and 16 about the axis l, respectively, so that the wire electrode l° Similarly, it is made to rotate around the axis l.

The wire cut electric discharge machining method using this electric discharge machining apparatus is almost the same as that using the apparatus shown in FIG. 1 described above.

In wire-cut electrical discharge machining using the electrical discharge machining apparatus shown in FIGS. 1 and 3, the wire electrode 1' rotates around its axis during machining.
' is removed from the image leading edge 25° 25 (see FIG. 2) of the cross section, so that it is consumed substantially uniformly.

The wire electrode used in the present invention is not limited to the cross-sectional shape illustrated in FIG. 2, but may be formed into any polygonal shape such as a triangle, quadrangle, or pentagon, or even any non-circular shape such as an ellipse. I can do it.

In the embodiments described above, a forming roller was used as a mold for forming, but a die may be used instead of such a forming roller.

Further, in the present invention, since it is sufficient that the wire electrode substantially rotates within the workpiece, for example, only the lower frame 16 in FIG. 4 may rotate or rotate. The direction may be either up or down.

(Operations and Effects of the Invention) According to the method of the present invention, since the wire electrode itself rotates, the wire electrode removes chips that stay in the narrow gap between the wire electrode and the processing portion of the workpiece during processing. Due to the rotational action of the electrode, the wire can be successively dragged out to a wide space on the opposite side to the side where processing is currently being carried out.Moreover, in this case, since the cross-sectional shape of the wire electrode is non-circular, the rotation of this electrode The scraping action works to remove chips from the peripheral area, allowing the chips to be discharged and removed more effectively.As a result, the gap between the workpiece and the wire electrode can be maintained almost constant, which prevents discharge defects from occurring. Moreover, there is no risk of short circuit between the two electrodes (also, the wire electrode does not wear out concentratedly on one side as in the conventional method, but is worn out almost evenly in the circumferential direction, so there is no risk of wire breakage). In addition, even if the wire entering the processing section is distorted (for example, if the cross-sectional shape or size of the electrode varies in the longitudinal direction), the The negative effects W (for example, defective discharge) are reduced, and thereby the accuracy can also be improved.Furthermore, according to the present invention, the wire electrode is formed by a mold provided on the front side of the workpiece. Therefore, in carrying out the present invention, any wire electrode can be used as long as it has a diameter larger than the size of the mold.

[Brief explanation of drawings]

Fig. 2 is a schematic explanatory view of the entire structure of an example of a wire-cut electric discharge machining apparatus for carrying out the present invention, and Fig. 2 is an enlarged explanatory view showing a forming roller used in the electric discharge machining apparatus of Fig. 1.
FIG. 3 is a perspective view showing a wire electrode rotation drive device used in the electrical discharge machining device shown in FIG. FIG. 2 is an overall schematic explanatory diagram showing a processing device. 1... Wire electrode before forming, 1゛... Wire electrode after forming, 7... Workpiece, 8... Forming roller (mold)
, 9... Wire electrode rotation drive device, 12... Processing section.

Claims (1)

[Claims] In a wire cut electric discharge machining method in which a workpiece is cut into a desired shape while a wire electrode is running and electric discharge is generated between the wire electrode and the workpiece, the running wire electrode is A wire-cut electrical discharge machining method characterized in that the workpiece is formed into a non-circular cross-sectional shape by passing through a mold provided on the rear side of the workpiece, and cutting is performed while rotating the traveling wire electrode.