JPH01228727A - Wire cut electric discharge machining method - Google Patents

Abstract

PURPOSE:To enhance the working efficiency by automatically determining a compensation path which changes offset values in an interference section when it is determined that the interference of the moving path of a wire cut electrode occurs, and by selectively setting a machining condition corresponding to the offset value in the interference section. CONSTITUTION:Data of various kinds of offset values 22, 24 are previously stored in memory, and in accordance with these two kinds of data, the presence of interferences of the wire diameter compensation paths 1a-5a on shape machining paths 1-5 is computed each time when the shape machining paths 1-5 are changed on an NC program. With a result of the computation, if an interference occurs, an offset value 22 and a machining condition corresponding to the offset value 22, which are suitable for the shape machining path and which give no interference are selected from data previously stored in memory. A wire diameter compensation path is set in accordance with thus selected data, and then machining on the shape machining path on which the interference occurs is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wire electrical discharge machining method that does not cause interference of wire electrode trajectories on a shape machining path.

[Conventional technology]

FIG. 5 is an overall configuration diagram showing, for example, a conventional wire electrical discharge machining bag. In the figure, (c) is a numerical control device that controls the entire wire electrical discharge machine, and - indicates the wire 1 as the pole - and the conductive material. The machining power supply unit applies a high-frequency pulse voltage between the workpiece II and the e9° wheel is a movable table that fixes the workpiece 6υ and moves in the XY axis directions.The -9th branch is a drive motor and numerically controlled The movable table -9- is driven by the command from the device (c).

-1■ is a power supply die that supplies the high frequency/<Rus city pressure output from the processing power supply section - to the wire W, pole ■, - is a wire feed bobbin that supplies wire electric current tIi-, I7+3 is a wire electrode... This is a wire winding bobbin for winding.

Figure 6 is a schematic diagram showing the machining state, depicting a horizontal cross section of the wire electrode and workpiece 11) during machining. In the figure, ■ is the diameter of the wire electrode, QB is the discharge gap, and ku is the diameter. correction! Or the amount of offset (hereinafter referred to as offset amount), the wire w! This is 1/2 of the pole diameter (■) plus the discharge gear slope.

Further, N represents a machining locus along which the center of the wire electrode wheel passes, and is located at a position separated by an offset amount (a) from the final finished shape - on the workpiece 13G.

Moreover, FIGS. 7 and 8 are schematic diagrams showing the operation of wire diameter correction, and FIG.
The figure shows a case where a corner R portion smaller than the offset amount is machined. In FIG. 7, (1) to (5) are NC program paths representing the desired final shape, (la
) to (5a) are wire diameter correction paths located at positions shifted by an offset il from the No. program paths (1) to (5). 01) to 041 represent the intersections of adjacent wire diameter correction meridians K(la) to (5a), respectively. On the other hand, in FIG. 8, (6) to (10 are the NCs shown in FIG.
NC program path representing the final shape, same as program paths (1) to (5), (6a) to (loa) Wire diameter correction path, r19 to (to), same as wire diameter correction path 1g (la) to (5a) each represents the intersection of adjacent wire diameter correction paths. Further, ``■'' and 翰 are the center and radius of the arc locus of the NC program path in a part of the corner.

Next, the operation will be explained. Move one wheel of the movable table (to) according to the commands from the numerical control device (c), and then I
! IC[X)woNCpro';f la l-route (1)-(
2) - (3) - (4) - + (5). At this time, in order to obtain the desired final shape, the wire radius plus the discharge gear slope, that is, the offset amount. Wire ti must be moved along a path that deviates from the NC program path. This is called the wire diameter correction function. However, when machining a narrow groove as shown in Fig. 7, if you find a path that is offset by the amount of offset from the NC program path, it will be as shown in (la) to (5a), and the corrected machining diameter! It can be seen that (2a) and (4a) intersect, indicating that interference of the fiya wt poles occurs.

When interference occurs, a cut occurs in the workpiece, making it impossible to process the desired shape. Also, when machining a part of a corner having a radius with a smaller offset amount as shown in FIG. 8, a cutback occurs on the radius-corrected path and a cut 01) is generated in the workpiece.

[The problem that the invention attempts to solve]

The conventional wire electric discharge machining method is performed as described above, so if interference occurs in the wire diameter correction path, a cut will be made in the workpiece, and the machining must be stopped. In order to restart the process, the NC-fa migram must be corrected or the offset amount must be changed and then re-processed. This poses a problem that must be solved in that it significantly reduces machining setup and machining efficiency.

This invention was made in order to solve the above problems, and provides a wire electrical discharge machining method that can avoid interference and continue machining without stopping machining when interference occurs in the wire diameter correction path. The purpose is to obtain.

[Means to solve the problem]

The wire electrical discharge machining method according to the present invention automatically determines a correction path in which the offset amount is changed at the interference generating part (ζ) when it is determined that interference of the wire tW trajectory occurs, and also automatically determines a correction path in which the offset amount is changed at the interference generating part (ζ). This allows processing conditions to be selectively set.

[Effect]

The wire electric discharge machining method according to the present invention calculates the interference of the wire diameter correction path every time the shape machining path changes, and based on the calculation result, a pre-stored offset amount is determined in the shape machining path where the interference occurs. data and machining condition data corresponding to the offset amount are selected, and a wire diameter correction path is set based on each of the selected data.

[Embodiments of the invention]

Hereinafter, an embodiment of the present invention will be explained with reference to the drawings. 1st
2 and 2 correspond to FIGS. 7 and 8 showing conventional embodiments. In the figures, (1) to QO, (la
) to (10a) t are the same as those shown in FIGS. 7 and 8, respectively, and represent the No. program path and the wire diameter correction path, respectively. Also, for the αD~ side, the intersections of adjacent wire diameter correction i paths are shown similarly to FIGS. 7 and 8. The slope is the wire gain, (goods), the cause is the normal discharge gap and offset amount, □□□, 624 is the discharge gap and offset amount when interference occurs, 弼, く is the arc center and arc radius of a part of the corner .

Next, the operation will be explained.

The machining shape in Fig. 1 is the same as Fig. 7, and in the first step of finishing the No. program path (1) to (5), which is the final shape of the tokoya, the wire diameter part is removed from the No. program path. Since it is necessary to move the wire center to a distant position, first obtain the corrected value WIP (la) shifted by the offset amount from the NG program path (1), and then from the same (No program path (2)). Find a correction path (f) that is separated by the offset amount (a).Then, these two correction paths (la).

Find the intersection (6) of (2a). Thereafter, in the same manner, the intersection point of the correction path - ~ α knob is determined, and the wire diameter correction meridian H(la) to (5a) passing through this intersection point is determined. However, in the correction path based on the offset amount shown in Fig. 1, it can be seen that interference on the correction path remains as shown in Fig. 7, so φυ, the offset amount (c) at which no interference occurs is determined by the offset amount and the machining conditions. Select the wheel from the table (43), find the wire diameter correction path at a position offset by 1e24 from the No. program path (2), and recalculate the intersection with (to 1). When the center of W/F/NtM passes the intersection αυ of the wire diameter correction path, the machining conditions are changed to the machining conditions selected from the machining condition table (to), and the apparent offset amount is reduced by decreasing the gap. From (C)I, reduce the size. Then, the correction path (
8a) and (4a), the correction path is similarly recalculated. After that, when the center of the wire electrode passes through the intersection point α of the correction path, the machining conditions are returned to the state of the interference generating part 'a'.In this way, the offset amount is changed in the machining locus before and after the interference generating part. Interference is avoided by recalculating the correction path and switching to a machining condition corresponding to the offset amount from the countershaft ζ machining condition table.

Also, to explain about FIG. 2 which shows the same shape as FIG.
), (8), and (9), after changing the offset amount by 1 degree, recalculate the correction path and process at the intersection (end) and intersection (end) of the correction path before and after part of the corner. Switch conditions. At the intersection (to), change the machining conditions from '31) to (a) on the machining table, and then switch to the intersection (to).
In (to), the processing conditions are switched from (to) to (b).

Further, in the above embodiment, the case of the wire electric discharge machining V device was explained, but it may also be a die-sinking electric discharge machining equipment.
The same effects as in the above embodiment can be expected.

〔Effect of the invention〕

As described above, according to the present invention, even if interference occurs in the wire diameter correction path, there is no need to stop machining or change the NC program and re-machining, thereby improving machining efficiency and achieving high quality. This has the effect that a workpiece can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an operational principle diagram showing the operation of corrected route calculation according to an embodiment of the present invention, FIG. 2 is an operational principle diagram showing the operation of another corrected route calculation according to one embodiment of the present invention, and FIG. A machining condition table showing the correspondence between machining conditions and offset amounts, FIG. 4 is a flowchart showing the process flow of the embodiment,
Figure 5 is an overall configuration diagram showing a conventional wire electrical discharge machining device.
Figure 6 is a cross-sectional view of the wire pole and workpiece schematically showing the shape during wire electrical discharge machining, Figure 7 is an operating principle diagram showing the operation of conventional correction path calculation, and Figure 8 is the conventional FIG. 6 is an operation principle diagram showing another correction path calculation operation. In the figure, (1) to (5) are No program paths, (
1a) to (5a) are wire diameter correction paths, 1 is the offset 1 when there is no interference, and [Yes] is the offset amount when there is interference. In Figure 1, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] Electrical discharge machining is performed on a wire diameter correction path that adds an offset amount consisting of the wire electrode radius and discharge gap to the shape machining dimensions of the NC program that commands the final finished shape of the workpiece, and the workpiece is machined with the final finished shape. In a wire electric discharge machining method for producing an object, data on various offset amounts and data on machining conditions corresponding to the offset amounts are stored in advance, and each time the shape machining path of the NC program changes, the shape machining of the NC program is performed. Based on the path information, it is calculated whether or not interference occurs in the wire diameter correction path for each shape machining path, and if interference occurs based on the calculation result, the shape machining path is adapted and no interference occurs. An offset amount and machining conditions corresponding to the offset amount are selected from the pre-stored data, a wire diameter correction path is set based on the selected data, and machining of the shape machining path where the interference occurs is executed. A wire electrical discharge machining method characterized by: