JPS58192722A - Wire cut electrospark machining method - Google Patents

Abstract

PURPOSE:To cut highly precisely the curved section by wire cut electrospark machining, by determining the lag of machining due to the bent of a wire electrode, and correcting the course of the machining, based on the lag. CONSTITUTION:In wire cut electrospark machining, due to the bent of a wire electrode caused by discharge pressure or the like, a machining lag (a) will take place. When a leading end of a work is machined, the machining lag (a) is measured, and the cutting course is corrected. The machining course of the curved section is corrected in such a way that the machining lag (a) is advanced tangentially of the curve. Thus, the cutting of the curved section can be effected highly efficiently.

Description

[Detailed description of the invention] [Technical field of invention] This invention relates to an improvement in a wire cut electric discharge machining method.

[Technical background of the invention and its problems] Generally speaking, wire-cut electrical discharge machining involves moving the workpiece (W) in the orthogonal direction and holding it on a small XY table (IIJ:), as shown in Figure 1. At the same time, the table (1) is moved in a direction perpendicular to the moving direction (Z).
direction) K The wire electrode (2) traveling and the workpiece (W
) is carried out by applying a pulse voltage to cause a discharge. Therefore, a computer is attached to the device, and the shape of the table is machined based on the required program stored in the computer. However, the wire electrode (2) is The wire electrode (2) is generally a thin wire made of steel, brass, tungsten, etc., with a diameter of about 0.05 m to 0.25 tm. As shown, it is mainly caused by the reaction force of the discharge.

The intermediate portion of the wire electrode (2) facing the cut portion (Wl) bends backward with respect to the cutting direction shown by the arrow (A).

Therefore, the cut portion (Wl) is one dimension behind the line connecting the guide lines 3) of the wire electrodes (2) placed on both sides of the workpiece (5). When such a phenomenon occurs, there is almost no problem when cutting a straight section, but when machining a circular arc section, the cutting direction changes to the open side, so the required cut cannot be made as shown in Figure 3. Song 11
4), the curve (5) drawn inside the curve (5) is used for cutting, resulting in a machining error. However, such machining errors are caused by the workpiece (W) compared to the discharge energy.
) when the moving speed is large, the angle becomes large, so in order to reduce the error, it is necessary to reduce the moving speed, or cut with a cut margin and perform correction processing after cutting.

[Object of the Invention] An object of the present invention is to provide a wire-cut electric discharge machining method that can accurately cut an arcuate portion without requiring a reduction in the moving speed of a workpiece relative to a wire electrode.

[Summary of the invention] Using a device connected to a computer to a drive control device that regulates the movement of a workpiece relative to a wire electrode, the amount of machining delay caused by the deflection K of the wire electrode during electric discharge machining is measured, Processing is performed by modifying the computer program described in E, which regulates the movement of the workpiece relative to the wire electrode, according to the amount of lag.

Embodiments of the Invention] First, an example of a wire-cut electrical discharge machining apparatus used for carrying out the invention will be described.

This processing device has a wire electrode (2) and a workpiece (W).
) is machined into the desired shape by moving the workpiece (W).
It is held on the Y table (1) and each moving table (xx
), (1y) K are each installed with nine X-axis drive pulse motors (10x) and Y-axis drive pulse motors (10x).
y'), it is a trap that can be moved in any direction on the XY plane. This XY table (1)
The movement is carried out by the X-axis and Y-axis drive pulse motors (10x
), (10y) drive control device C1 connected to
L lucidity is controlled by 1l. On the other hand, the wire electrode (2
) is made of thin metal wires such as tungsten,
Penetrates the XY table (1) and the workpiece (W) held thereon and extends in a direction (biaxial direction) perpendicular to the movement plane (XYsIF-plane) of the XY table (1). and its both ends are guide rollers (12a),
(12b) via Citesbourg (13a), (1
The spools (+3a), Q3b) attached to 3b'I are attached to rotating shafts (14a), (14b) that form part of the spool rotation mechanism, and the rotational drive of this spool rotation mechanism This allows it to travel in either direction, up or down, at any speed. This wire electrode (2) is connected via a sliding contact to a pulse power source 09 connected to the XY table (1). Further, this pulse power source 09 and the drive control device C113 are each connected to a combiator QQ.
It is connected to the. Furthermore, machining fluid is supplied to the machining portion of the workpiece (W) from the machining fluid supply device αD through the pump (P) end and the nozzle 08.

In electric discharge machining, a workpiece (W) is mounted on an XY table (1), and one end of a wire electrode (2) wound around one spool, for example, the spool h (13a), is attached to the workpiece (W). The formed machining start point (W2) is inserted and wound around the other spool (13b) K. Thereafter, the spool rotation mechanism rotates the spool ridge, for example, to cause the wire electrode (2) to run at a constant speed in the direction of arrow (B). In this case, the spool (14a) is allowed to rotate freely and the wire electrode (2)
Simultaneously with the start of running, a constant pulse voltage is applied between the wire electrode (2) and the workpiece (W) from the pulse power supply (c) based on a command from the combiator fIe to cause discharge. , the computer (Ie) operates the drive control device based on the stored program trap, and moves the XY table according to the above program.

In this case, since the cutter is manufactured according to the cutting shape,
This is corrected as shown in FIG. That is, if the required cutting shape is a circular arc as shown in curve (4) shown in Fig. 5, then the tangent to this curve (4) (from the contact point (T) of A curve Q obtained by connecting points separated by the machining delay dimension a from Pa on the machining start side to Qa in the cutting progress direction indicated by the arrow.
Modify the above program using υ. 1. Regarding the measurement of machining delay dimension a, the large umbrella of a changes depending on the machining conditions, so the workpiece (W) is measured under the same conditions as the actual machining.
Or, it is better to find it by cutting the same thing several times. That is, for example, after finding the coordinates of the cutting direction of the XY table (1) when cutting several n unnecessary parts of the workpiece (W),
The wire electrode (2) is moved back and approached again to connect the wire electrode (2) and the workpiece (
When performing electric discharge machining on W), even if the wire electrode (2) is deflected, no machining error will occur due to the deflection when cutting the straight line, and the machining error caused by the deflection will be corrected for the curved section. Since it can be cut into corners, it can be processed into the desired shape. In general, the machining error due to cutting delay becomes smaller as the radius of the arc becomes larger, as shown by the curved line in Figure 6, but it becomes too large to be ignored for arcs with a radius of 3 m or less.

It is especially effective when applied to cuts with arcuate portions of this size.

First, other embodiments will be described. First, regarding the measurement of the machining lag dimension a, in the above example, the case where it is determined by cutting off unnecessary parts of the workpiece is shown, but for the actual workpiece, machining of the required shape starts from the starting point of electrical discharge machining. It is possible to take advantage of the run-up section until the end.

By determining the machining button lag dimension a using this method, it is possible to efficiently perform eccentric machining to cut into the required shape.In addition, the electrical discharge machining machine NK is equipped with a measuring device that automatically measures the machining lag dimension a. Then, by using an electrical discharge machining device that automatically measures the cut-off gap dimension a in the run-up section and automatically corrects the computer program based on this measurement result, it is possible to perform the required electrical discharge machining even more efficiently. .

Furthermore, although the above-mentioned embodiment shows the modification of a shape having a single circular arc portion, the present invention has a plurality of circular arcs with different radii as shown by curve (4) in FIG. This invention can also be applied to circular arcs and radii (consisting of two circular arcs).The present invention can also be applied to cases where the circular arc is not part of a correct circle.

Furthermore, although the above embodiments have been described in which the workpiece is cut by moving the workpiece relative to the wire electrode, the wire electrode may be moved relative to the workpiece to pressurize the workpiece for cutting.

[Effects of the Invention] As described above, the present invention measures the amount of machining lag caused by the deflection of the wire electrode during electrical discharge machining, and corrects the relative movement of the workpiece to the wire electrode [IK] based on the amount of lag. This makes it possible to cut curved sections accurately.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the conventional wire-cut electric discharge machining, Fig. 2 is an enlarged view of the cutting part, Fig. 3 is an explanatory diagram of occurrence of machining errors, and Fig. 4 is an explanatory diagram of the actual wire cut electric discharge machining of this invention. Fig. 5 is a diagram illustrating correction of machining errors, Fig. 6 is a diagram showing the relationship between arc size and machining error, and Fig. 7 is a curve made of multiple arcs. FIG. (1)...XY table, (2)...wire electrode,
On...Pulse motor, αυ...Drive control device, α
K...Spool, 0!9...Pulse power supply, (I
Q... Combiator. Agent Patent Attorney Norihiro Chika Kensuke (and 1 other person) 71 Plan 40 Figure 7 → Half-C of solid air Figure 7

Claims (1)

[Claims] A wire-cut electrical discharge machining method K for electrical discharge machining the workpiece by controlling the relative movement of a wire electrode between the workpiece and the workpiece according to a program stored in a computer.
A wire cut electrical discharge machining method characterized in that the amount of machining delay caused by the deflection K of the wire electrode is measured, and the amount of machining is corrected.