JPS6236811B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for controlling a line electrode electrical discharge machine, and in particular, a method for controlling a line electrode electrical discharge machine, in particular, first information corresponding to the cutting shape of one side of a workpiece, and second information corresponding to the cutting shape of the other side of a workpiece. A recording medium on which information is recorded in advance, and a control information supply means for outputting drive control information based on the first and second information, and a numerically controlled driving device for the line electrode support part is also provided with the control information. The present invention relates to a method for controlling a line electrode electrical discharge machine, which causes a numerical control drive device to follow a machining table.

A wire electrode electrical discharge machine is known in which a wire electrode is passed through the workpiece and cutting is performed by moving the workpiece relative to the wire electrode in a direction perpendicular to the feeding direction of the wire electrode. There is. Needless to say, in the electric discharge machine, a pulse voltage, for example, is applied between the wire electrode and the workpiece, and distilled water, for example, is sprayed onto the machined part. From this, the wire electrode electrical discharge machine can be considered to be a jig saw that utilizes electrical discharge machining means.

Conventionally, in the above-mentioned wire electrode electrical discharge machine, the wire electrode is fixed in a direction perpendicular to the surface of the workpiece, and the workpiece is driven and controlled by a numerical control drive device (hereinafter abbreviated as NC). be made into In this case, the cut surface on the workpiece is a plane perpendicular to the surface of the workpiece, but it is desired that the cut surface be slightly tapered if necessary. In order to provide the taper, it is not enough to simply tilt and fix the wire electrode with respect to the surface of the workpiece, but it is necessary to sequentially control the inclination as cutting progresses. For this reason, many inventions have been made to date, but
Difficulties arise, for example, when cutting shapes where tapered surfaces join together. In other words, there is generally a difference between the cutting distance on the front side of the workpiece and the cutting distance on the back side of the workpiece. A method is adopted in which the movement mode is switched to compensate for the above difference. However, while the moving mode of the line electrode is switched, a dent occurs in the cut surface. If the ratio between the width of the line electrode and the cutting width is defined as the amount of overcut, it means that the amount of overcut increases in the above case. The increase in overcut amount is
This can be considered to be caused by electrolytic action occurring between the electrode and the workpiece or minute fluctuations in the electrode position due to electrode feeding.

The present invention aims to solve the above-mentioned problems, and aims to control the amount of overcut so that it becomes uniform on the surface of a workpiece.
An object of the present invention is to perform this control with a simple configuration. This will be explained below with reference to the drawings.

FIG. 1 is a structural diagram of a control method for a line electrode electrical discharge machine according to an embodiment of the present invention, FIGS. 2A and B are explanatory diagrams explaining the concept of control according to the present invention, and FIG. 3 is an embodiment of a control method according to the present invention. The control configuration diagram and FIG. 4 each show an embodiment configuration diagram of the main parts thereof.

In FIG. 1, 1 is an electric discharge machine fixing part, 2 is a machining table, 3 is a workpiece, 4 is a wire electrode, 5 is a first wire electrode support part, 6 is a second wire electrode support part,
7 is a numerical control drive device for the processing table, 8 is a numerical control drive device for the first wire electrode support portion, 9 is a numerical control drive device for the second wire electrode support portion, and 10 is a wire electrode mounting table, which is the electric discharge machine fixing portion 1. 11 is a wire electrode sending reel which receives a driving force in the direction of the dotted line from a torque motor (not shown), but in reality, the wire is moved in the direction of the arrow shown below. 12 is a wire electrode winding reel that winds up the wire electrode 4 in the direction of the solid arrow shown in the figure; 13 is a wire electrode mounting table adjustment unit for manually rotating the handle 14; The line electrode mounting table 10 is moved up and down with respect to the fixed part 1, and 15 represents a processing table 2 mounting body which connects the processing table NC7 and the processing table 2, respectively.

In a conventional wire electrode electrical discharge machine that does not taper the cut surface, the wire electrode support parts NC8 and NC9 do not exist in FIG. 1, and the wire electrode support parts NC8 and NC9 do not exist.
can be considered to be on a line exactly perpendicular to the surface of the workpiece 3. Then, a hole is made to pass through the workpiece 3 placed on the processing table 2, the first line electrode 4 is passed through the hole, and distilled water is injected while sending the line electrode 4 in the direction of the arrow shown in the figure. , a pulse voltage is applied between the wire electrode 4 and the workpiece 3. In this state, the processing table 2, that is, the workpiece 3, is moved in the horizontal direction using the NC 7. As a result, the workpiece 3 is cut like a jig saw.

However, as stated at the beginning of this specification, it is desirable to provide a taper to the cut surface. Therefore, in the present invention, line electrode support parts NC8 and NC9 are provided to control the relative positions of the line electrode support parts 5 and 6.

In the case of the present invention, the processing table NC7 controls the processing table 2 in the X coordinate direction and the Y coordinate direction so that the line electrode contact position S on the back surface of the workpiece 3 is maintained at a desired position, for example. On the other hand, the first line electrode support part NC8 and/or the second line electrode support part NC9 are moved by the line electrode support part 5 and / or 6.

The electric discharge machine control of the present invention will be explained below with reference to FIG. 2, and the differences from this type of control conventionally known will be explained. In Figure 2, 3, 4, 5,
6 corresponds to FIG. 1, 16 is the top cut shape of the workpiece 3, 17 is the bottom cut shape of the workpiece 3, and 18
19 is a taper surface, 20 is a hole previously drilled in the workpiece 3, 4', 5', and 6' are moved wire electrodes, and the first wire electrode. The support part represents the second line electrode support part.

It is assumed that the wire electrode 4 is penetrated into the hole 20, and cutting is performed along the line 21 from the points A and B shown in the figure, until the wire electrode 4 reaches the points C and D shown in the figure. Next, it is assumed that the cutting process is carried out from points E and F to points G and H.

In this case, in the case of a conventional electrical discharge machine of this type,
It can be considered that it was controlled as follows. That is, it is assumed that the wire electrode 4 is penetrated into the hole 20 and the cutting process is started. At this time, the workpiece 3 is moved to the left in the figure by the NC 7 while the wire electrode support parts 5 and 6 remain stationary. Then, when the line electrode 4 reaches points C' and D' shown in FIG. Only part 5 is moved. This causes the line electrode 4 to reach points C and D shown in FIG. 2B. Then, switch the drive mode again and keep the line electrode supports 5 and 6 stationary in that state.
The workpiece 3 is driven by the NC7.

Therefore, the line electrode 4 is connected to points A and B shown in FIG. 2B.
Driving speed and point C′ while moving from to point C′, D′
An extreme change occurs in the driving speed while moving from D' to points C and D. Therefore, the above-mentioned overcut amount changes and unevenness occurs on the cut surface 18.

In the case of other conventional electric discharge machines of this type, only the line electrode support part 5 is moved with the line electrode 4 penetrated through the hole 20, so that the line electrode 4 is at the same inclination angle θ as the illustrated line electrode 4'. Then, the drive mode is changed and only the NC 7 is driven to cut the line electrode 4 to the position of the line electrode 4' shown in the figure. Furthermore, in the case of other electric discharge machines, cutting is performed from points A, B to points C, D'' with the wire electrode 4 kept vertically using only the NC 7, and then the drive mode is switched and the wire electrode support 5 is cut. and 6 in opposite directions to move the line electrodes to points C and D.
tilt it to In both of the above two cases, undesirable unevenness occurs due to drive mode switching.

In order to solve this problem, in the case of the present invention, the linear electrode 4 is kept at a uniform driving speed while moving from points A and B to points C and D in the figure. That is, while the wire electrode 4 moves from point A to point C on the back surface of the workpiece 3, the wire electrode 4 moves from point B on the front surface of the workpiece 3.
Control is performed to advance from point D to point D.

As an example of this control, the NC 7 moves the workpiece 3 by a distance l ₂ in the direction of the arrow shown in the figure, that is, in the left direction, and during the movement of the workpiece 3, the NC 8 moves the first wire electrode support 5 by a distance ( l ₁ - l ₂ ) to the right, and during the movement of the workpiece 3, the NC 9 moves the second line electrode support 6 to the left by a distance (l ₂ - l ₃ ). In this case, the above distances l ₂ , l ₁ −l ₂ , l ₂
-l ₃ is (1) the cutting point A on the back surface of the workpiece 3,
(2) The X, Y coordinates of cutting points B and D on the surface of the workpiece 3; (3) From the first wire electrode support 5 to the back surface of the workpiece 3. (4) Vertical distance L ₁ from the second wire electrode support part 6 to the workpiece 3
Given the vertical distance L ₂ to the back surface of (5) and the thickness t of the workpiece 3, these (1), (2),
It is obtained from the information in (3), (4), and (5). That is, for example, the coordinates of point A, point B, point C, and point D are (0,
0), (0,0), (X,0), (x,0), the moving distance l ₂ of the workpiece 3 is given by l ₂ =X (1), and the first The moving distance (l ₁ - l ₂ ) of the line electrode support part 5 is given by l ₁ - l ₂ = L ₁ /t(x-X) (2), and the moving distance of the second line electrode support part 6 ( l ₂ - _{l 3} ) is given by l ₂ - l ₃ = L ₂ /t(x-X) (3). Here, if the moving speed of the workpiece 3 by the NC 7 is v, then the moving speed v(5) of the first wire electrode support part 5 by the NC 8 is v(5) from equations (1) and (2) above. =l ₁ -l ₂ /l ₂・v=L ₁ /t・x−X/
X・v(4), and on the other hand, the moving speed v(6) of the second linear electrode support part 6 by the NC9 is given by equations (1) and (3) above, v(6)=l ₂ - l ₃ /l ₂・v=L ₂ /t・x−X/
It is given by X・v(5).

Further, as another example of control according to the present invention, NC
7 moves the workpiece 3 to the left by a distance l ₃ , while the NC 8 moves the first wire electrode support 5.
Similarly, even in the case where the NC 9 is controlled so as to move the second line electrode support part 6 to the right by a distance (l ₁ - l ₃ ), the first line electrode support part 5 The moving speed of can be obtained.

Therefore, in the case of the present invention, at least information corresponding to the cut shape of the workpiece 3 (points A, B,
C and D coordinate information) is recorded on a recording medium, for example, a magnetic tape, and based on this information, NC8 and/or NC9 move the workpiece 3 by a predetermined distance while NC8 and/or NC9 move the workpiece 3 by a predetermined distance. The line electrode support section 5 and/or the second line electrode support section 6 are controlled to move uniformly.

FIG. 3 shows a control configuration according to an embodiment of the present invention.

In FIG. 3, 22 is a recording medium such as a magnetic tape, 23 is a tape reader, and 24 is a control information supply means that supplies control information to NC7, NC8, and NC9 based on the information on the recording medium 22. 25-1 is a driving pulse generating means in the X coordinate direction which generates a driving pulse signal every time a logic "1" signal in the X coordinate component of control information a is input to drive the NC 8 in the X coordinate direction; 25-2 is drive pulse generation means in the Y coordinate direction, which generates a pulse signal for driving the NC 8 in the Y coordinate direction every time a logic "1" signal in the Y coordinate component of control information a is input; 26-1;
and 26-2 are the drive pulse generating means 2, respectively.
The drive pulse generating means 26-1 is configured similarly to 5-1 and 25-2, and the pulse generating means 26-1 connects the NC9 to
The pulse generating means 26-2 is driven in the coordinate direction and is NC.
9 is driven in the Y-coordinate direction, and 7, 8, and 9 are those that correspond to the reference numerals in FIG. 1, respectively.

The tape 22 includes, for example, (1) first information (for example, second information) corresponding to the cutting shape of one side of the workpiece 3;
In the case of the figure, coordinate information of the points forming the cut shape on the back surface of the workpiece 3, such as illustrated points A, C, E, G, etc., and information that the cut shape between the above points is a straight line), (2 ) Second information corresponding to the cut shape on the other surface of the workpiece 3 (for example, in the case of FIG. 2, the illustrated points B, D, F, H, etc. constitute the cut shape on the surface of the workpiece 3) coordinate information of the points and information that the cut shape between the above points is a straight line), (3)
Thickness information of the workpiece 3 (illustrated distance t in the case of Fig. 2)
(4) Vertical distance information from the first line electrode support part 5 to one surface of the workpiece 3 (information corresponding to the illustrated distance L ₁ in the case of FIG. 2), ( Five)
Vertical distance information from the second line electrode support portion 6 to one surface of the workpiece 3 (information corresponding to the illustrated distance L ₂ in the case of FIG. 2) is recorded in advance. The tape reader 23 has the above (1), (2), (3),
Each of the information (4) and (5) is read and the read result is output to the control information supply means 24. The control information supplying means 24 is configured as described above in FIG.
Based on the information in (1), (2), (3), (4), and (5), NC7
In addition to supplying drive command information corresponding to the drive distance of the workpiece table 2 to
On the other hand, the generated pulses generated following the movement progress of the work table 2 are used as control input signals for the NC.
Control information a for driving the NC 8 and other control information b for driving the NC 9 are supplied. Here, the control information a for the NC 8 outputted by the control information supply means 24 is supplied to the NC 8 by inputting its X component to the drive pulse generation means 25-1 and its Y component to the drive pulse generation means 25-2, respectively. On the other hand, control information b for the NC9 outputted by the supplying means 24 is also transmitted to the NC via the drive pulse generating means 26-1 and 26-2.
9.

FIG. 4 shows the control information supply means 24 in FIG.
1 shows an example configuration.

In FIG. 4, reference numeral 27 represents a processing table driving pulse generating means, and the driving pulse generating means 27
generates a pulse according to the machining conditions unless the content of the first register 28 is zero, and the generated pulse causes the first register 28 and the third register 3 to
The contents of 4 and 35 are sequentially subtracted, and when the contents of the first register 28 become "0", pulse generation is stopped. 28 is a first register in which X coordinate component information X of the first information corresponding to the cutting shape on the back side of the workpiece 3 is stored, and the stored content X
is sequentially subtracted by the processing table drive pulse generating means 27, and 29 is a second register in which the X coordinate component information x of the second information corresponding to the cutting shape on the front side of the workpiece 3 is It represents what is stored. 30 represents a first calculation means, which calculates the information X stored in the first register 28, the information x stored in the second register 29, and the thickness information t of the workpiece 3. and the vertical distance information _L1 from the first line electrode support part 5 to the back surface of the workpiece 3.
Information K ₁ X/x−X is obtained from K ₁ (=t/L ₁ ). 3
1 is a second calculating means, and the determining means 31 calculates the above information Information K _{2 X} /x−X is obtained from the variable amount K ₂ (=t/L ₂ ) based on 32 is a register that stores the information K ₁ X/x−X obtained by the first calculation means 30; 33 is the second calculation means 31;
Each of the registers stores the above-mentioned information K ₂ X/x−X determined by 34 is a third register which stores the information K ₁ X/x-X stored in the register 32 and sequentially generates the information K ₁ The subtractor 35 is _a third register which stores the information K ₂ 36 is a first comparison means that generates a zero detection signal when the subtraction content of the third register 34 is zero; 37 is a second comparison means. Each of these represents a signal that generates a zero detection signal when the subtraction content of the third register 35 is zero. Further, 8, 9, 24, 25-1, and 26-1 represent the numbers corresponding to the numbers in FIG. 3, respectively. 2nd below
The control operation of the control information supplying means 24 will be explained by taking as an example the case where the workpiece 3 is cut from points A and B to points C and D along the straight line 21 in FIGS. In addition, in Figure 2 A and B, point A,
For example, the X and Y coordinates of points B, C, and D are (0,0), (0,0), (10,0), (11,0), respectively.
Also, the thickness t of the workpiece 3 is 1, and the vertical distance is
Let L ₁ be 2 and the vertical distance L ₂ be 2. This results in
The first register 28 is given the X-coordinate component of the cutting line from point A to point C, ie, information "10", as information The X coordinate component of the cutting line from to point D, ie, information "11", for example, is given.
Further, _{the information} K _{1 The} information _{K 2} Further, the processing table driving pulse generating means 27 generates pulses equal to 10 pulses corresponding to the X coordinate component of the cutting line from point A to point C during the cutting process.

The information "10" stored in the first register 28 is sequentially subtracted one by one by the pulses generated from the processing table driving pulse generating means 27. When the content becomes "0", the state signal (not shown) is input to the NC 7, and the NC 7 finishes driving the work table 2 in the cutting process. At the same time, the X coordinate value for the next processing is supplied to the first register 28 and the second register 29. On the other hand, the information "5" given by the first arithmetic means 30 and supplied to the third register 34 via the register 32 and the information "5" given by the second arithmetic means 31 to the register 33
The other information "5" stored in the third register 35 through Means 3
6 and the second comparing means 37.
The first comparison means 36 to which the contents of the third register 34 are input generates a zero detection signal, while the second comparison means 37 to which the contents of the third register 35 are input likewise generates a zero detection signal. Generate a signal. At the same time, the contents of registers 32 and 33 are again set in registers 34 and 35, and a similar subtraction is performed. Therefore, the driving pulse generating means 25-1
outputs one drive pulse signal each time a zero detection signal is input from the first comparison means 36, and the first line electrode support part NC8 outputs the first drive pulse signal based on the drive pulse signal. The line electrode support section 5 is moved in the X coordinate direction by a distance in the X coordinate direction corresponding to two drive pulse signals. That is, the NC 8 is connected to the first wire electrode support part 5 while the cutting process is being performed.
to the second part of the workpiece 3 by the distance of the X coordinate component "2"
Move it in the direction opposite to the direction of the arrow shown in Figure B.
On the other hand, the drive pulse generating means 26-1 similarly outputs two drive pulse signals, and the second line electrode support section
During the cutting process, the NC 9 moves the second line electrode support 6 in the X coordinate direction by a distance equal to the moving distance of the first line electrode support 5. In this case, the second line electrode support 6 is moved in the same direction as the moving direction of the workpiece 3.

As a result, during the cutting process, the first line electrode support 5 is uniformly moved to the position corresponding to the coordinates (12,0) in FIG. 2A, and the second line electrode support 6 is moved to the second It is uniformly moved to a position corresponding to coordinates (8,0) in Figure A. In other words, the workpiece 3 moves from points A and B at coordinates (0,0) to coordinates (10,0,11,
0) is cut to points C and D. When the cutting process is completed, information based on the coordinates of points C, D, E, and F is input to the control information supply means 24, and the supply means 24 is inputted based on the information. and supplies control information to NC8 and NC9. In this case, although not shown in FIG. 4, the control information supply means 24 is connected to the first register 2.
A register corresponding to the second register 29 and storing Y-coordinate component information corresponding to the cutting shape on the back side of the workpiece 3, and a register corresponding to the second register 29 on the front side of the workpiece 3. A register for storing Y-coordinate component information corresponding to the cutting shape, and a circuit component corresponding to the circuit components below the first and second calculation means 30 and 31 shown in FIG. 4, which are provided on the output side of the two registers. The cutting process from points C and D to points E and F is controlled by a control means based on these Y coordinate component information,
NC8 and NC9 now move the first line electrode support part 5 and the second line electrode support part 6, respectively, in the Y coordinate direction.

As described above, according to the present invention, the control information supply means 24 supplies control information to the NCs 8 and 9 following the movement of the workpiece 3, and the workpiece 3 can be cut in a good manner. can. Further, according to the present invention, it is sufficient to record information corresponding to the cut shape of the workpiece 3 on one recording medium. In addition, when obtaining a cut shape with a uniformly determined taper angle, a known method for interpolating the tool diameter can be used to obtain a cut shape based on the information corresponding to the cut shape of one side of the workpiece. It is not so troublesome to obtain two pieces of cutting shape information as in the present invention.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of a control method for a line electrode electrical discharge machine according to an embodiment of the present invention, FIGS. 2A and B are explanatory diagrams explaining the concept of control according to the present invention, and FIG. 3 is an embodiment of a control method according to the present invention. Control block diagram: FIG. 4 shows a block diagram of an embodiment of its main parts. In the figure, 2 is a processing table, 3 is a workpiece, 4 is a wire electrode, 5 is a first wire electrode support section, 6 is a second wire electrode support section, 7 is a processing table numerical control drive device, and 8 is a a first line electrode support numerically controlled drive device;
9 is a second line electrode support numerical control drive device, 22
24 is a recording medium, 24 is a control information supply means, 28 is a first register, 29 is a second register, 32,3
3 represents the third register according to the present invention, 36 represents the first comparing means, and 37 represents the second comparing means.

Claims (1)

[Claims] 1. A workpiece placed on a processing table, a wire electrode arranged to penetrate through the workpiece, and the wire electrode supported on one side of the workpiece. 1st
and a second line electrode support part that supports the line electrode on the other side of the workpiece, and applying a voltage between the line electrode and the workpiece. In a wire electrode electrical discharge machine that cuts the workpiece, first information corresponding to the cutting shape of one side of the workpiece and second information corresponding to the cutting shape of the other side of the workpiece are provided. a recording medium on which information is recorded in advance; a processing table numerically controlled drive device that drives the workpiece placed on the processing table in accordance with the cutting shape; and a control information supply means for supplying drive control information to the line electrode support numerically controlled drive device based on the information on the recording medium, The control information supply means determines information corresponding to a desired change in the slope of the line electrode based on the first information and the second information on the recording medium, and controls the information to correspond to the change in slope. operates to subtract information by a drive pulse corresponding to the processing table numerical control drive device, and to supply a drive pulse for driving the line electrode support numerical control device based on the subtraction result, and supplies the control information. A line electrode electrical discharge machine, characterized in that the line electrode electrical discharge machine has a control unit that keeps the driving of the line electrode supporting portion by the means and the driving of the processing table by the processing table numerical control drive device in step with drive generation pulses. Control method. 2 The control information supplying means is controlled based on the information on the recording medium and information based on the relative positional relationship between the wire electrode support and the workpiece obtained from the information. A method for controlling a wire electrode electrical discharge machine according to claim 1, characterized in that the method is configured as follows. 3. The control information supply means includes a first register storing the first information X on the recording medium, a second register storing the second information x, and the information X and the information x. Motozuku Information K
A third register is provided for storing X/x-X (x>X), and the information X stored in the first register and the information KX/x-X stored in the third register are provided. subtracted by drive generation pulses for the numerically controlled drive device of the processing table, respectively;
Line electrode electrical discharge machining according to claim 2, characterized in that a drive pulse for driving the line electrode support numerical control drive device is supplied based on the subtraction result of the third register. Machine control method.