JPS6085830A - Wire electric discharge machining method - Google Patents

Abstract

PURPOSE:To make electric discharge machining so as to be carried out at an accurate work position in relation to a reference hole, by letting a wire electrode relatively shift to a work on the basis of compensated date, while constituting it so as to machine the work, in case of a wire electric discharge machining method. CONSTITUTION:In advance of wire electric discharge machining, an angle thetam made between a straight line SL connecting both centers of a reference hole BH1 and another reference hole BH2 in time of setting a work to a setting table of a wire electric discharge machining and an Xm-axis of machining coordinate system Xm-Ym is measured. In this case, an angle thetaw made between the SL and the Xm-axis of work coordinate systems Xw-Yw, or an Xw-axis for specifying this angle thetaw and axial components a and b (thetaw=tan<-1>b/a) are all stored in memory in advance whereby a differential portion of these two angles is found, and with this differential portion used, cutting path data included in the numerically controlled data is compensated. With a suchlike method, wire electric discharge machining can be carried out at an accurate work position in relation to the reference hole.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a wire electrical discharge machining method in a wire electrical discharge machine, and in particular, even if the attachment position of the workpiece to the wire electrical discharge machine is shifted, it is possible to prevent the workpiece from being formed in advance. The present invention relates to a wire electrical discharge machining method that allows machining of reference holes according to instructions.

<Prior Art> When a die is created using a wire electrical discharge machine, it is necessary to machine the die at an accurate position relative to a plurality of reference holes that are previously formed in a workpiece. For this reason, it is necessary to accurately mount all workpieces on the mounting table, in other words, to mount all workpieces on the mounting table so that the coordinate system of the reference hole (referred to as the workpiece coordinate system) and the machine coordinate system of the wire electric discharge machine are parallel to each other. It needs to be installed on the FIG. 1 is an explanatory diagram when the workpiece coordinate system Xw-Yw is rotated by an angle Δ0 with respect to the machine coordinate system Xtn-Ym. Actual nI for reference holes BH1 and BH2 provided in workpiece WK! Even if numerical control data is created to perform wire electrical discharge machining along the path PT, the workpiece coordinate system X w - Y w is tilted with respect to the machine coordinate system Then, in actual machining, the wire electrode moves along the dotted line path PT', and the resulting die is rotated by an angle Δθ with respect to the reference hole. This is because in actual machining, the wire electrode is moved in the machine coordinate system based on numerical control data. For example, using numerical control data to cut and move a wire electrode to a point P1 that is far away in the Yw-axis direction in the workpiece coordinate system XW-YW from the machining start hole STH, the wire? )f, the pole moves toward a point Pf that is separated by L in the Ym-axis direction in the mechanical coordinate system Xm-Ym. Therefore, in order to perform wire electrical discharge machining at an accurate position with respect to the reference hole Bl (1, BH2), the workpiece coordinate system
One workpiece WK must be mounted on the table TBL so that -Yw and the machine coordinate system Xm-Ym are parallel to each other.

<Disadvantages of the prior art> However, the conventional workpiece coordinate system Xw-Yw is the machine coordinate system Xm.
-YmK It is very difficult to mount the workpiece so that it is parallel to the workpiece, and some mounting errors inevitably occur, making it impossible to perform wire electrical discharge machining at an accurate position relative to the reference hole.

<Object of the Invention> The object of the present invention is to provide a wire electrical discharge machining method that can perform wire electrical discharge machining at an accurate position relative to the reference hole Gτ even if the workpiece coordinate system is not parallel to the machine coordinate system due to an error in mounting the workpiece. The goal is to provide the following.

<Summary of the Invention> FIGS. 2(A) and 2(B) are schematic explanatory diagrams of the present invention, and the direct translation SL connecting two reference holes provided in the workpiece WK is the predetermined axis Xw of the workpiece coordinate system Xw-Yw. The angle θwfr
When the workpiece is set in a wire electric discharge machine, the straight line connecting the reference holes is the predetermined axis X in the machine coordinate system X m - Y rn.
Measure all the angles θm formed with m, and calculate the difference Δ0 between the two angles.
Then, use the difference to convert the numerical control data into '3-!
The turning path data is corrected, and the wire 4 wire 1 ( ) 2 poles are moved relative to the workpiece based on the corrected data to process the workpiece.

<Example> Fig. 3 is a side view of a wire electrical discharge machine to which the present invention can be applied. is the power supply capacitor box 3
is placed.

A workpiece mount 4 is disposed on the base 2, and the workpiece mount 4 is two-dimensionally movable on the base 2 by an X-direction drive motor and a Y-direction drive motor. . A workpiece 6 is mounted on the workpiece mounting base 4 with a clamp 5. 7 is a wire 41i pole, which runs in the direction of the arrow during electrical discharge machining. Reference numeral 8 denotes a delivery reel on which unused wire electrodes are wound and layered, and 9 a brake roller that applies a brake to the delivery of the wire electric car, particularly in the pulling direction, on which the wire electrode is wound. 10 rollers, 11 is the lower guide roller, 12 is the upper idle roller,
13 is a roller, and 14 is a feed roller, which are rotated once by a drive motor that fully drives the wire electrodes. A pinch roller 15 is pressed against the foot roller 14 by a spring 16. Note that the wire electrode 7 is connected to the feed roller 4
and pinch roller 5. 1γ is a take-up reel for winding up the used wire electrode.

FIG. 4 is a block diagram of an embodiment of the present invention, and FIG. 5 is a flowchart of processing.

Prior to wire electrical discharge machining, the straight line SL connecting the center of the reference hole BHI (see Figure 2) and the center of the reference hole BH2 when the workpiece is mounted on the mount of the wire electrical discharge machine is the machine coordinate system Xm-Ym. Measure the angle θm with the Xm axis. The angle θ that the straight line SL makes with the Xw axis of the workpiece coordinate system Xw-Yw
Since the axial component a%b (θw=m-') in the XW-axis and Yw-axis directions for specifying W or the angle θW is not written in the design drawing, it can be written from the NC tape 101 or the operation panel 102. The input data h''' is stored in the RAM 103.

First, pass the wire electrode through the first reference hole B)tl, tension the wire electrode, and then automatically center the reference hole BH1.
Execute wo. However, this automatic centering is well known. 1-
In other words, operation! When you select the automatic centering motor and the axis you want to move first in the channel 102, the processor 1
04, the automatic centering process is completely started under the control of the control program stored in the ROM 105. First, rough centering is performed to position the wire electrode to the approximate center of the hole, and then accurate centering is performed.

For rough centering, 0) As shown in FIG.
The wire electrode is moved toward the workpiece at a speed of min ).

That is, the processor 104 has a predetermined number of 37
Amount of movement Δx that should be moved in seconds (for example, 16m5ec)
Calculated using the linear formula % formula % (1), the pulse distributor 106 calculates the Δχ every 31 seconds.
Output to. The pulse distributor 106 performs a pulse distribution calculation based on the input ΔX, generates a distribution pulse XP, and generates a distribution pulse XP on the X-axis. Input to circuit 107X, X-axis motor 10
Rotate 8X to move the wire electrode relative to the workpiece. The processor 104 calculates ΔX every time ΔT transitions.
input to the f ie pulse distributor 106 to move the wire electrode toward the workpiece, and calculate Xa±ΔX−+X a (2) every 31 seconds (the sign depends on the direction of movement). R.A.
The current position Xa in the X-axis direction stored in M103 is updated.

(b) The wire electrode approaches the workpiece through the above process, and when the wire electrode comes into contact with the workpiece, the short circuit detector 10
A short circuit signal WSS is generated from 9, and the short circuit signal WSS is taken into the processor 104 via the data input/output device 110.

(c) Due to the generation of the short circuit signal, the processor 104 stops inputting ΔX to the pulse distributor 106, stops the wire electrode at point B (see FIG. 6), and also stops the wire electrode at the current position XaTh on the 1 end point position Xn as RAM1
Stored in 03.

) Then, the processor 104 similarly moves the wire S:pole in the -X direction to the position of the 0 point in FIG.
IζAM103 measured at the second end point position Xc' in the axial direction
to be memorized.

(E) After that, the processor 104 executes X l ” (
XB + Xc ) / 2 Determine the center position Xl in the X-axis direction between points B and C using (3), and let Xt be the remaining movement amount Xr.
xiΔT every second K/# is input to the pulse distributor 106.

As a result, the wire electrode moves toward the center position (point D in FIG. 6). Processor 104 also processes (2) every 31 seconds.
) is performed to update the current position in the X-axis direction, and the following equation (%) (4) is calculated every 31 seconds to update the remaining movement amount Xr k stored in the RAM 103. Then, when Xr=0, that is, when the wire electrode reaches the center position (point D), the movement of the wire electrode is stopped.

(to) After that, do the above process in the Y-axis direction? To repeat, the wire electrode is positioned approximately at the center of the first reference hole BHI, and the center position (XI, Yl) is stored in the RAM. In the same Figure 4, 107Y and 108Y are the sensors in the Y-axis direction, respectively. The circuit is a serve motor.

(G) In step b, lower the feed speed to the above (a).
By repeating the processes from to (f), the accurate center position (XO%YO1) of the first reference hole BH1 will be determined.

(e) After that, the current position X IIs Y a stored in the RAM 103 is set to all zeros (0→Xa, 0→Y
a). That is, the current position XaYa when the wire electrode exists at the center position of the reference hole BHI is set to zero.

(S) Next, after cutting the wire electrode completely, press the jog feed button on the operation panel to position it directly below the second reference hole BH2i wire running path.

When the jog feed button in the X-axis direction is pressed, the processor 104 performs the process in step 0) to move the wire electrode in the X-axis direction relative to the workpiece, and also sets the current position XIL in the X-axis direction. Similarly, when the jog button in the Y-axis direction is pressed, the processor 04 performs the process of step 0) to move the wire electrode i in the Y-axis direction and simultaneously update the current position Ya in the Y-axis direction.

(b) After that, pass the wire electrode through the reference hole BH2 and repeat the steps (a) to (g) above to remove the wire electrode. When positioned at the center of the second reference hole BH2, the current position Xa, Y stored in the RAM 103 at that time
a is from the center of the first reference hole BH1 to the second reference hole BH2
The axis components x and y in the mechanical coordinate system up to the center of

Then, the X%F is stored in the RAM 103.

After that, the processor 04 calculates the angle θmf that the straight line SL makes with the Xm axis using the following formula, and calculates the inclination Δ0 of the workpiece coordinate system with respect to the machine coordinate system using the following formula. Store it in the RAM 103.

Through the above processing, once the inclinations Δ and θ are equal, the following wire electrical discharge machining of the die is executed based on the numerical control data stored in the NC Tezo 101. That is, (a) First, a wire electrode is passed through the machining start hole 5T)l (see FIG. 1), and the wire electrode is positioned at the machining start point using the automatic centering. Further, a voltage is applied between the wire electrode and the workpiece, and a start button on the operation panel 102 is pressed.

(b) If the startup is successful, will the processor 104 be able to read the NC data from the NC data reader 111? c- and 1 block of NC program.
Read from C tape 101. Listen, NC tape 101
Path data from the machining start hole STH, M function commands, etc. are recorded as NC data.

(c) The processor 104 determines whether the read NC data is path data based on the control of the control program. It is determined whether the NC data contains the alphabet X or Y, which is a word address, to determine whether it is path data or layer data.

) If the NC data does not include path data, the processor 104 executes normal NC processing and returns to the NCC processing execution step.

(E) On the other hand, if the NC data includes passage data,
For example, if the NC data is data GOIXX Yy indicating linear cutting movement 4, the processor 104 corrects the path data using the following equation. Δθ is RAM10
The inclination angle of the workpiece coordinate system with respect to the machine coordinate system, which is stored in !3, is stored in ! , 7 are the coordinate values of the end point position of the block, numeric values following the alphabet XSY in the word address word, and x' and y' are the coordinate values of the end point position after correction.

Also, if the NC data is data G02 (or GO3) indicating an arc path ', j'.

(to) After that, if the processor has straight line data (
Using x' and y' obtained by formula 7), or if it is circular arc data, use X' obtained by formula (7) and (8).
% y', i', and j' to perform normal straight line cutting processing or circular arc cutting processing.

(g) When the process in step (g) is completed, the processor repeats the process of reading and unloading the next NC data.

(G) Then, when the M code MO2 or M2O indicating the program end or tape end is read out from the NC tape 101, the wire electrical discharge machining ends. As a result, the wire electrode moves relative to the workpiece along the path shown by the solid line in Figure 1, and the workpiece coordinate system Xv-Yw changes from the machine coordinate system Xm-Y.
Wire electrical discharge machining can be performed at an accurate position relative to the reference hole even if the hole is tilted relative to m.

<Effects of the Invention> As described above, according to the present invention, data for specifying the angle that a straight line connecting two reference holes provided in a workpiece makes with a predetermined axis of the workpiece coordinate system is stored, and all wires of the workpiece are Measure the angle that the straight line connecting the reference holes makes with a predetermined axis in the machine coordinate system when set in the electrical discharge machine, calculate the difference between the two angles, and use this difference to determine the path included in the numerical control data. Since the data is corrected and the wire electrode is moved relative to the workpiece based on the corrected data to process the workpiece, the workpiece coordinate system Even if the system is tilted h with respect to the system Xm-Ym, wire electrical discharge machining can be performed at an accurate workpiece position with respect to the reference hole.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the desired machining path and the actual machining path when the workpiece coordinate system is inclined with respect to the machine coordinate system, FIG. 2 is a schematic explanatory diagram of the present invention, and FIG. 4 is a block diagram of an embodiment of the present invention, FIG. 5 is a flowchart of the process of the present invention, and FIG. 6 is an explanatory diagram of centering. 101...NC tape 102...Operation/Zenel 103...RAM 104...
...Processor 105...ROM 106...
...Z9Atsu[1109...Short circuit detector 110...Data input/output device 111...
...NC7J-Event reader patent applicant FANUC Co., Ltd. agent Patent attorney Kanki Saito

Claims (1)

[Claims] (1) In a wire electrical discharge machining method for a wire electrical discharge machine in which a wire electrode is moved relative to the workpiece based on numerical control data to machine the workpiece, two Data for specifying the angle that a straight line connecting the reference holes makes with a predetermined axis of the workpiece coordinate system is stored, and when the workpiece is set in a wire electric discharge machine, the straight line connecting the reference holes is determined in the machine coordinate system. Measure the angle formed with a predetermined axis, calculate the difference between the two angles, use the difference to correct all path data included in the numerical control data, and adjust the wire electrode relative to the workpiece based on the corrected data. A wire electrical discharge machining method characterized by machining a workpiece using a moving source. (2) The wire according to claim 11, characterized in that the coordinate axes of the workpiece coordinate system and the coordinate axes of the machine coordinate system are parallel to each other when the workpiece is set in a wire electric discharge machine with full strain. Electrical discharge machining method. (3) The wire electrical discharge machining method according to claim 11 or (2), characterized in that the data is each axis component in a workpiece coordinate system of a straight line connecting the reference holes. (4) The wire electric discharge machining method according to claim 11 or (2), wherein the data is an angle between a straight line connecting all the reference holes and a predetermined axis in workpiece coordinates. (5) Specifying the angle that the straight line connecting the reference holes makes with a predetermined axis of the machine coordinate system using each axis component of the straight line in the machine coordinate system.
) or (2).