JPS5919638A - Wire-cut electric discharge machining - Google Patents

Abstract

PURPOSE:To perform second cut and machining at plural points automatically, by storing the working path in a memory while returning from the work-end point to the work-start point contrarily from the machining operation. CONSTITUTION:When performing second-cut machining or machining at plural points through wire-cut discharge machining, a wire electrode is cut and stretched again in the machining start hole. Here the machining path is stored in a memory without cutting the wire electrode and upon reaching to the end point of machining, the memory is called to move the wire electrode contrarily from the machining operation to return to the machining start point WCH. Consequently if second cut machining or plural machining is performed from the start point of machining; other machining can be continued automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire-cut electric discharge machining method, in particular, a method for performing the same machining or another machining by going backwards along an already machining path according to a program command or a command from an operation panel. This invention relates to a wire-cut electric discharge machining method that allows for.

Recently, a new machining method called second cut has been proposed as a wire cut electrical discharge machining method.

This second cut is a method of machining the same machining path two or more times under different machining conditions, such as discharge energy, machining speed, wire tensile strength, etc., and is effective in improving machining accuracy. Now, the first electric discharge machining in the case of a second cut corresponds to rough cutting in NC machining such as a lathe, and the capacity i+ of the discharge capacitor is increased to increase the discharge energy, and the electric discharge machining is performed at a relatively low speed. The second cut after this corresponds to the finishing cut, and the discharge capacitor is made smaller to reduce the discharge energy, and the wire is stretched and discharge machining is performed at a high speed. In such a second cut, as shown in FIG. 1, the machining path W CP #c is
Perform the first electric discharge machining along the line up to point A, and after completing the first electric discharge machining, cut the wire by hand, and then move the workpiece relative to the wire using manual operations such as jig feed. ζ Move the wire axis to the machining start hole W
After matching the CH, manually pass the wire through the machining start hole and re-stretch the wire to the wire travel system. After completing the re-stretching, change the machining conditions and move the workpiece relative to the wire in the machining path WCP again. A second cut is made by moving the image to However, in this method of performing the second cut by manual operation, (a) the second cut cannot be performed automatically, and operator intervention is always required. (Middle) There was a drawback that operations, especially operations such as passing the wire through the machining start hole, were complicated. For this reason, a method can be considered in which an automatic wire feeder device (referred to as an AWF device) is installed in a wire cut electrical discharge machine to automatically perform a second cut.

That is, the first electrical discharge machining is performed by dripping from the machining start hole WCH into the machining path up to point a, and after the first electrical discharge machining is completed, the wire is cut by the AWF device, and then the workpiece is moved relative to the wire by the program. to align the axis of the wire with the machining start hole WCH, and then move the wire to the AWF.
The device automatically passes the wire through the machining start hole, re-stretches the wire to the wire running system, changes the machining conditions, and returns to the machining path WCP.
Then, the workpiece is moved relative to the wire and a second cut is made. However, this method requires a wire-cut electrical discharge machine to be equipped with an expensive AWF device. Further, there is a demand for wire-cut electric discharge machines to perform a large number of punches one after another. For example, when machining multiple wires (-Pi to P4) around the machining start hole WCH as shown in Fig. 2, or when machining a wire after machining with one punch as shown in Fig. 6, This is a case where punching is performed one after another after positioning the wire.However, conventionally, the wire is cut after completing one punching process, and then the axis of the wire is aligned with the machining start hole WC.
H (Fig. 2) or position the wire outside the workpiece (Fig. 3), and then insert the wire into the machining start hole W.
The wire was passed through the CH, re-strung on the wire running system, and subjected to the first punching process, and then punching processes were performed one after another in the same manner. Therefore, in order to perform multiple punches automatically, an expensive AWF device must be installed.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a wire-cut electrical discharge machining method that allows the wire electrode to overflow into a previously machined path and move the wire electrode back to a desired position. Another object of the present invention is to provide a wire-cut electrical discharge machining method that can automatically perform a second cut without cutting the wire. Furthermore, another object of the present invention is that the wire can be stopped just before the punch is cut off and then moved back to the machining start hole or outside the workpiece, and a plurality of punches can be automatically machined in succession. It is an object of the present invention to provide a wire cut electric discharge machining method that can be used.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 4 is a block diagram of an NC device for realizing the wire cut electric discharge machining method according to the present invention, and is an example applied to a second cut.

Various subprograms are stored in the subprogram memory 101. The subprogram is, for example, a program of the machining path MPS from the machining start point WCH to the point re shown in Fig. 5, and as shown in Fig. 6, the name of the subprogram (the part marked ■), the machining start point coordinates, etc. It has a G function command (part marked ◎) for setting (Xs, Ys), machining path data (part marked O), and an M function command (part marked @) for instructing a return to the main program. The main program for the second cut is recorded on the NC tape 102. The main program is as shown in Figure 7.
, NC data for first cut (0 part),
It has NC data for the second cut (the part marked with ■), NC data for the third cut (the part marked with @), and M function command' for program termination (the part marked with ■). The NC data for the first cut includes the feed rate at the time of the first cut (instructed by the numerical values reflected in the word addresses F and F), the machining conditions at the time of the first cut (instructed by the numerical values reflected in the word addresses S and S), and the first cut. Wire diameter offset amount at the time of cutting (instructed by word address D and the numerical value following D) and subprogram 01
Subprogram call instruction (M2S
Plooo;) and an M function command (M70; )'P that reverses the path machined by the subprogram (already machined path) and returns the wire to the machining starting point. Further, the NC data for the second cut and the third cut have the same data as the NC data for the first cut. just,
The only difference from the first cut NC data is the feed rate, processing conditions, and wire diameter offset i.

The tape reader 105 reads the main program recorded on the NC tape 1021 one block at a time and inputs it to the arithmetic processing section 104. The arithmetic processing unit 104 is the tape reader 1
The main program data read from 03I is determined and processing based on the main program data is performed. That is, the alphabet F is determined, the feed rate following F is output to the pulse distributor 105, the alphabet S is determined, and the numerical value following S is input to the wire-cut electrical discharge machine 201 via the data input/output device 106. , the machining conditions are selected according to the numerical value, the alphabet D is determined, the wire diameter is selected according to the numerical value following D, and the wire diameter correction process is performed according to the wire diameter. In addition, the arithmetic processing unit 1
04 is a subprogram call instruction M98i, if it is determined, M
The subprogram indicated by the subprogram name following 2S is read block by block from the memory 101, numerical control processing is executed based on the subprogram, the wire is moved relative to the workpiece, and the electrical discharge machine is operated as desired. Perform wire cut electrical discharge machining on the passageway. That is, the machining start point WCi (
The coordinates (Xs, Ys)'i working memory) 107 are stored in the machining start point area 107a. Next, once the path data is read from the subprogram memory 101, normal NC processing is executed and
Processing path information is sequentially stored in the path storage memo IJ 1081. For example, assume that path data read from subprogram memory is incremental and commanded as follows:

G (X1Y to 11X, 8.yl; ■X△
X, Y△y,; ■ Go2 X△x3Y△y3 I△11 J△j1
■GOI X△X4 Y△y4
■The arithmetic processing unit 104 first creates a work memo based on the straight line cutting data of ■. The remaining movement amount Xr Yr is stored in the remaining movement amount storage area 107b of J 107 as Δxl+△y1,
Also, the pulse distributor 1051 △X1. Input Δyx, and store the dotted cutting data of ■ in the path storage memory 108.

In addition, since it is an incremental command, the passage memory memo 1J
1081 straight line cutting data is stored as is, but if it is an absolute command, an incremental value is calculated and the incremental value is G Iffff all commands Ol,
Stored together with Go2 and G(15). The pulse distributor 105 outputs incremental cutting data Δ”1 p
△y! is given, perform the well-known pulse distribution operation,
The distribution pulses xp and Yp for the X and Y axes are input to the servo units 109X and 109Y for the X and Y axes, and the servo motors 110X and 110Y are rotated to move the table on which the workpiece (not shown) is placed relative to the wire. move the target. Moreover, the distribution pulses Xp and Yp are calculated by the arithmetic processing unit 1.
04 is also input. The arithmetic processing unit 104 receives the distribution pulse
The remaining movement amount is Xr every time p and Yp occur.

Yr and current positions Xa and Ya are updated according to the following formula.

Xrl −+X1, Yr −1→YrXB −
1→Xa, ya1→ya (However, the sign depends on the moving direction) Then, )(r=Q, yr=0, the pulse distribution completion signal DEN is generated, and the pulse distribution calculation based on the cutting data in ■ is completed. When the pulse distribution completion signal DEN is generated, the linear cutting data (■) is read out from the subprogram memory 101, and △X! and △yg are similarly stored in the remaining movement amount storage area 107'b. , pulse distributor 1
05, and the straight line cutting data (2) is stored in the storage area next to the storage area in which the cutting data (2) is stored in the path storage memory 108. Thereafter, the same processing as in the case of the cutting data (3) is performed. When the pulse distribution based on the linear cutting data of (2) is completed, the circular arc (clockwise direction) cutting data of (2) is read out from the subprogram memory 101, the circular cutting process is executed, and this circular cutting data is stored in the path storage memory 108. is memorized. Furthermore, (bs, A)'s
) is the distance component (incremental value) between the arc start point and the arc end point, and (mu11.Δj is the distance component (incremental value) between the arc start point and the arc center. When the distribution based on the arc cutting data is completed, , ■ are read out from the subprogram memory 101, and are thereafter subjected to exactly the same processing as the straight line cutting data of ■.The straight line cutting data of ■ is stored in the path storage memory 108ζ.

When the wire reaches the end point Pe, in other words, when the pulse distribution calculation based on the straight line cutting data (3) is completed, M99; is read from the subprogram memory 101. M
When 99 is read out, the arithmetic processing unit 104 causes the tape reader 103 to read the next block N from the NC tape 102.
Read the C data. As a result, the M function command (M2O) for moving the wire into the vertical machining path and moving backward is read. When M2O is read, the arithmetic processing unit 104 thereafter reads the path data from the path storage memory 108 in the reverse order of the storage order. That is, GO1x△X4YΔy4;■ G02x△X3Y△y3I△11J△j1 ■G 0
1 X△X @Y△)'meaning; ■GOI X
ΔXIYΔy1; Read in the order of (2) and perform backward processing. For example, if the linear cutting data of ■ is read out, the signs of the incremental values of X and Y are changed and GOI After completion (after completion of pulse distribution), read the arc cutting data of ■ from the path storage memory 108 and read the arc cutting data Go 5 X-△XI Y-△Y@I (△X1-
Δll) J (Δy, -ΔJ1); (3
J and performs counterclockwise circular interpolation processing.

In addition, Go3 is the G function command for counterclockwise circular interpolation, -△X
1. −△ys are the incremental values from the arc starting point p, 75) to the arc ending point P, respectively, (ΔXs−△!1),
(Δy3−Δ”1) is an incremental value from the arc starting point P to the arc center.

When the circular interpolation is completed, the arithmetic processing unit 104 reads the linear cutting data of ■ from the path storage memory 108, changes the signs of the incremental values of X and Y, and calculates GOI X-△X2.
Y-△)'1; (Performs normal straight-line cutting processing as Change the sign of the incremental value of co'+ X-ΔXI Y-Δ)'1 +
(Usual straight line cutting processing is performed as D'. Then,
When the pulse distribution calculation based on the data of V is completed, the wire is positioned at the machining start hole WCH, and the backward movement of the wire along the already machined path E is completed. In addition, when reversing the wire, press the dry run switch 11 on the operation panel 111.
Turn on 1a and send the wire in a dry run. That is, the commanded speed is ignored and the wire is moved relative to the workpiece at the speed set on the speed dial on the operation panel.

When the backward processing is completed, the arithmetic processing unit 104 controls the tape reader 105 to read the NC data of the second cut into the NC data.
It reads from the tape 102 and performs the same processing as the first cut. Then, when the second cut process is completed, the third cut process is performed and a series of second cut processes (
Wholesaling ends.

Fig. 8 is an explanatory diagram explaining the data storage method in the path memory memo-IJ 10 B (Fig. 4), the same figure (5) is an explanatory diagram of the fixed length data storage method, and the figure FB) is an explanatory diagram explaining the data storage method in the path memory memo-IJ 10 B (Fig. 4). FIG. 3 is an explanatory diagram of a data storage method.

In a wire-cut electric discharge machine, if the wire-cut electric discharge machine is to perform taper machining, a total of 8
Axis data is required. That is.

X, Y to move the table in an arc.

Four axes, I and J, are required, and in order to move the wire guide along an arc, [J, V, K r L
This is because four axes are required. Therefore, in the fixed-length data storage method, there are 10 fixed-length storage areas for each moving block.
sa, 108b, 108C--... are prepared, and the incremental values (including zero) of each axis and the G function command (
G.O.O.

GOl, GO2, GO3), and the data can be read in the opposite direction to the storage direction.

On the other hand, in the variable length data storage method, storage areas 108a', 108b', 108C', and
,... are made variable in size. That is, in the variable length data storage method, a data length storage area, a G function command storage area, a flag area for each axis, and a variable length incremental storage area are prepared for each movement block, and the flag for the axis whose incremental value is zero is # o # wo is stored in the area, "1" is stored in the flag area of the axis where the incremental value is not zero, and the incremental values of the axes with 1" are stored in the incremental storage area in order. Note that even in the variable length data storage method, data can be read in the opposite direction to the storage direction.

Now, 1 or more is a backward M function command (
M2O) is inserted, and when the M2O is read, the wire is moved in the opposite direction to the machining direction relative to the workpiece, but the reverse command does not necessarily have to be given in the program, but can be done on the operation panel. Start button 111b dedicated to 111
It is also possible to provide an input button and input the information by pressing the start button. Such manual operation can be used when performing a second cut by manual ζ, when it is desired to return the wire to the machining start point without cutting it, or when returning directly to the machining start point would interfere with the clamp of the workpiece.

By the way, in manually operated backward processing, a backward command can be issued even in the middle of one block. Therefore, the processing of the arithmetic processing unit 104 is slightly more complicated than when the program issues a backward auxiliary command (M2O) after the completion of movement of one block. That is, the arithmetic processing unit 10
4 counts each axis distribution pulse xp, Yp and stores the movement amount Xm, Ym in each axis direction in one block in a movement amount storage area 107di. Then, if a reverse command button 111b on the operation panel 111 is operated to input a reverse command to the arithmetic processing unit 104, the arithmetic processing unit 104 immediately stops the pulse distribution calculation, and if the current block is straight-line cutting, GOl x -xm Y-Ym: Generate and based on the data, or if circular cutting, G02 (or GD3) X-XmY-ym 1 body + 1
-Xm)J(ΔJ1-Ym): is generated, and the backward process is executed based on the arc data. If it moves by Xm and 7m in the X and Y axis directions, the pulse distribution completion signal DEN is output, and from then on, the path storage memory 10
The path data is sequentially read from 8, and the wire returns to the machining amount minus the starting point in the same way as if a reverse command was issued by the program.

As described above, according to the present invention, it is possible to overflow the vertical processing path and move the wire electrode backward to a desired position.

Furthermore, a second cut can be made automatically without cutting the wire. Furthermore, the movement of the wire is stopped just before the punch is cut off, and then the wire is moved backwards along the vertical machining path toward the machining start hole or outside the workpiece, and the punch on the rear side is machined. It is possible to automatically process a large number of punches in succession.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram for explaining the second cut, Figs. 2 and 3 are explanatory diagrams for machining a large number of punches, and Fig. 4 is a block diagram for realizing the wire cut electric discharge machining method. 6 is an explanatory diagram of a second cut according to the present invention, FIG. 6 is an example of a sub program, FIG. 7 is an example of a main program, and FIG. 8 is an explanatory diagram of a machining path storage memory. 101...Subprogram memory, 102...NC
Chi 7', 104... Arithmetic processing unit, 105... Pulse distributor, 106... Input/output device, 201... Wire cut electric discharge machine patent applicant FANUC Co., Ltd. agent Patent attorney Sanegai Tsuji 1 person $5 Figure 6 Figure 010oo; ---1■ Figure 7 Mo2;

Claims (7)

[Claims] (1) In a wire cut electric discharge machining method in which a desired electric discharge machining is performed on the workpiece while moving the workpiece relative to a wire electrode based on machining command data, the workpiece returns to the low machining path during the NC program. A step of inputting a backward command, a step of sequentially storing machining paths from a predetermined point in a memory in parallel with the machining operation, a step of reading out current machining path information from the memory in the reverse order of storage according to the backward command, and reading. A wire-cut electric discharge machining method characterized in that the workpiece is moved relative to the wire electrode in a direction opposite to the machining direction and returned to the predetermined point based on the current machining path information. (2) The wire-cut electric discharge machining method according to claim (1), wherein the coordinates of the predetermined point are specified by an NC program. (3) NC data regarding machining paths are sequentially stored in the memory to store low machining paths, and the NC data is read from the memory in reverse order to move the workpiece relative to the wire in the opposite direction. A wire-cut electric discharge machining method according to claim (1) or (2). (4) In a wire cut electrical discharge machining method in which a desired electrical discharge machining is performed on a workpiece while moving the workpiece relative to the wire electrode based on machining command data, the machining operation is performed along a machining path from a predetermined point. A step of inputting a reverse command to overflow to the lower machining path and return to the lower machining path from the operation panel, a step of reading the current machining path information from the memory in the reverse order of the storage order by the reverse command. A wire-cut electric discharge machining method characterized in that the workpiece is moved relative to the wire electrode and in the opposite direction to the machining direction based on current machining path information and returned to the predetermined point. (5) The wire cut electric discharge machining method further includes the step of storing the current position of the workpiece relative to the wire electrode;
The step includes the step of moving the workpiece from the current position toward the starting point of the current block relative to the wire electrode in accordance with the backward command; The workpiece is then moved relative to the wire electrode toward the predetermined point by reading the processed path information from the memory and moving the workpiece relative to the wire electrode.
4) The wire cut electrical discharge machining method described in section 4). (6) The wire-cut electric discharge machining method according to claim 4 or 5, characterized in that NG data regarding machining paths is sequentially stored in the memory, and machining paths are stored. (7) The wire-cut electrical discharge machining method according to claim 4, (5), or (6) of the claim H, characterized in that the coordinate % of the predetermined point is specified by an NC program. .