JP2768239B2 - Wire electric discharge machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire electric discharge machine, and more particularly to a wire electric discharge machine capable of measuring a dimension of a workpiece.

[0002]

2. Description of the Related Art FIG. 6 is a perspective view showing a schematic structure of a conventional wire electric discharge machine. In FIG. 6, 1 is a wire electrode, 2 is an upper wire guide supporting the wire electrode 1, 3
Is the lower wire guide, 4 is the processing table, 5 is the X-axis-Y
An axis cross table, 6 is an X-axis drive motor, 7 is a Y-axis drive motor, 8 is a workpiece mounted on the processing table 4, 9 is control means, 12 is CRT display means, and 13 is a keyboard. The control means 9 mainly includes a CPU 9a,
ROM 9b for storing a control program, RAM 9c for storing various data, X-axis drive motor driver 9d, Y
It comprises a shaft drive motor driver 9e and an interface 9f. The control means 9 controls the driver 9 based on a predetermined shape program for wire electric discharge machining.
The X-axis drive motor 6 and the Y-axis drive motor 7 are driven via d and the driver 9e to move the X-axis-Y-axis cross table 5 in an arbitrary direction.

Next, in order to form a product shape, as an example, the processing conditions and offset value are changed along the same
The wire electric discharge machining and the dimension measurement when the st machining, the second machining, the third machining, and the shape machining are performed three times will be described. As the shape programs necessary for wire electric discharge machining, at least two types of programs, a shape machining program and a cut-off machining program, are required. These programs are stored in the ROM 9b of the control means 9 in advance.

[0004] A procedure in a conventional wire electric discharge machining will be described with reference to a flowchart of FIG. First, in step S301, shape processing is performed. R in control means 9
The X-axis drive motor 6 and the Y-axis drive motor 7 are driven according to the shape processing program stored in the OM 9b, and the processing table 4 is moved in the X-axis-Y-axis direction. Then, electric discharge is generated between the wire electrode 1 whose upper and lower portions are supported by the wire guides 2 and 3 and the workpiece 8 attached to the machining table 4 to perform wire electric discharge machining. In the shape processing, the first processing, the second processing, the third processing, and the third processing are performed by changing the processing conditions and the offset value along the same path. Next, in step S302, cut-off processing is performed. After the end of the shape processing in step S301, the cut-off processing is performed according to the cut-off processing program stored in the ROM 9b in the control means 9, and the shape of the product 8a is cut off from the workpiece 8 and separated. . Then, in step S303, dimension measurement is performed. The cut product 8a is measured using a micrometer, a three-dimensional measuring machine, or the like.

[0005]

As described above, conventionally, the finished dimension of the product 8a is cut off from the workpiece 8 and then manually measured using a micrometer or a three-dimensional measuring machine. Since it is performed, it is a separate process from the shape processing, and it takes time and effort. Also, as a result of the dimension measurement, product 8
Even if it is determined that the dimension of “a” has not reached the target value, the product 8a has already been cut off from the workpiece 8 and it is not possible to carry out additional processing such as correction processing using a wire electric discharge machine. It was impossible.

On the other hand, Japanese Patent Application Laid-Open No.
No. 6-9131, JP-A-57-212428
Report the technology of Japanese Utility Model Application Laid-Open No. 3-113725.
Can be. JP-A-56-9131 discloses a work piece
Electrical discharge machining is temporarily stopped during
Stop, discard the wire electrode and retreat a specified distance from the processing stop position
At the retracted position and modulate the wire electrode in the machining direction.
Move in the direction of the line and move from the tangent line between the wire electrode and the workpiece.
Measures the discharge gap and automatically adjusts the wire electrode offset
The technology required for the above is disclosed. However, electric discharge machining
Automatically determine the offset of the wire electrode
Although the finished dimensions of the product can be measured,
After cutting off from a micrometer, a three-dimensional measuring machine, etc.
It was necessary to implement it manually using

[0007] Also, Japanese Patent Application Laid-Open No. 57-212428 discloses
Is added in the processing section before processing the workpiece.
Stop the process once, and the direction of the processing groove formed in the processing section
The processing electrode and the workpiece are relatively moved to
Detects the contact between the electrode and the workpiece, and
The moving distance to be detected by automatic measurement, the offset value
Techniques for calculating are disclosed. However, this technology
Offset of wire electrode for electric discharge machining
The amount can be determined automatically based on the results of EDM.
Although it is possible, the finished dimensions of the product can be measured from the workpiece
After cutting off, use a micrometer or a three-dimensional measuring machine, etc.
It had to be performed manually.

In Japanese Utility Model Laid-Open No. 3-113725,
Is a wire electrode in the hole formed in the workpiece to be EDM
And moving the wire electrode to move the wall of the hole of the workpiece.
Contact the surface, detect the size of the hole, and
An automatic centering device for obtaining a heart is disclosed. But here
Move the wire electrode into contact with the wall surface of the hole in the workpiece
To detect the size of the hole.
Yes, but the machining program for the EDM
Not knowing, processing finished dimensions of products
It is difficult to obtain before cutting off an object.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has as its object to provide a wire electric discharge machine capable of measuring the dimensions of a workpiece after completion of shape processing and before cutting off.

[0010]

According to a first aspect of the present invention, there is provided a wire electric discharge machining apparatus which generates an electric discharge between a wire electrode and a workpiece to cause the workpiece mounted on a machining table to be connected to the wire electrode. Moving the wire electrode with respect to the workpiece according to a shape program at the time of wire electric discharge machining with the workpiece, and positioning the workpiece by bringing the workpiece into contact with the wire electrode; dimensions to measure the of. And according to the shape program
Addition before wire cut-off machining after wire electric discharge machining
Move the wire electrode with respect to the workpiece, and
On the machining path of the shape program corresponding to the measured position
Coordinate value and positioning operation by the wire positioning means
Coordinates with the coordinate values measured by the dimension measuring means after completion
The value difference is calculated.

According to a second aspect of the present invention, in addition to the first aspect , the wire electric discharge machine compares the coordinate value difference with a predetermined allowable value, and determines that the coordinate value difference exceeds the allowable value. When it is present, the workpiece is again subjected to wire electric discharge machining by the wire electrode.

[0012]

According to the first aspect of the present invention, the wire electrode is moved with respect to the workpiece in accordance with a shape program when the workpiece is subjected to wire electric discharge machining. It can enter without contacting the narrow slit-shaped part. In addition, for the workpiece before cutting off after wire electrical discharge machining,
The wire electrode is moved to a predetermined measurement position according to the shape program, and a coordinate value difference is calculated from a coordinate value on a machining path of the shape program at the measurement position and a coordinate value measured by contacting the workpiece. , Workpiece (product)
Required dimensions are measured before cutting off.

[0013] according to claim 2 wire electrical discharge machining apparatus, according to claim
In addition to the effect of 1, the calculated coordinate value difference is compared with a preset allowable value, and when it is larger than the allowable value, the workpiece (product) is subjected to wire electric discharge machining again. . That is, the workpiece (product) is subjected to correction processing or the like before cutting off.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to specific embodiments. FIG. 1 is a perspective view showing a schematic configuration of a wire electric discharge machine according to one embodiment of the present invention. In the figure, the same reference numerals and symbols as those of the conventional example indicate the same or corresponding components as those of the conventional example. In FIG. 1, 1 is a wire electrode, 2 is an upper wire guide supporting the wire electrode 1, 3 is a lower wire guide, 4 is a processing table, 5 is X
Axis-Y-axis cross table, 6, 7 are X-axis drive motor and Y-axis drive motor for moving X-axis-Y axis cross table 5 in an arbitrary direction, 8 is a workpiece mounted on processing table 4, 9 is a control means, 10 is a measurement command position input means for designating a measurement position, and 11 is a wire positioning means. Reference numeral 12 denotes CRT display means, and reference numeral 13 denotes a keyboard. The control means 9 mainly includes a CPU 9a, a ROM 9b for storing a control program, a RAM 9c for storing various data, a driver 9d for the X-axis drive motor 6, a driver 9e for the Y-axis drive motor 7, an interface 9f, and the like.

FIG. 4 is an enlarged perspective view showing an example of the dimension measurement in the wire electric discharge machine according to the present embodiment. The designation of the measurement position is for designating the dimension measurement position in advance before starting the processing. As shown in FIG. 4, when it is desired to execute wire positioning such that the coordinate value of the wire electrode 1 in the Y-axis direction with respect to the workpiece 8 is Y1, a measurement command position input means 10 for designating a measurement location. At Y =
What is necessary is just to specify as Y1. The wire positioning means 11 drives the X-axis drive motor 6 and the Y-axis drive motor 7 from a state where the wire electrode 1 and the workpiece 8 are not in contact with each other, and the gap between the wire electrode 1 and the workpiece 8 becomes zero. The processing table 4 is automatically moved to the position. When the processing table 4 reaches the position, the processing table 4 is temporarily stopped, and the coordinate value of each axis is read and stored by the control means 9.
Then, after that, the X-axis drive motor 6 and the Y-axis drive motor 7 are driven again to automatically move the processing table 4 to the first position where the wire electrode 1 and the workpiece 8 were not in contact with each other. is there.

Next, the control in the apparatus of this embodiment will be described with reference to the flow chart of the wire electric discharge machining control of FIG. 2 and the flow chart of the dimension measurement processing of FIG. << Wire Electrical Discharge Machining Control: See FIG. 2 >> In step S101 of FIG. 2, the measurement location is designated in advance by the measurement command position input means 10 for designating the measurement location before the start of the shape machining. Next, step S102
Then, the X-axis drive motor 6 and the Y-axis drive motor 7 are driven according to the shape processing program stored in the ROM 9b in the control means 9, and the processing table 4 is moved to the X-axis direction.
It is moved in the Y-axis direction. Then, an electric discharge is generated between the wire electrode 1 whose upper and lower portions are supported by the wire guides 2 and 3 and the workpiece 8 mounted on the machining table 4, thereby performing wire electric discharge machining. In the shape processing, the first condition, the second process, and the third process are performed by changing the processing conditions and the offset value along the same path.
It is processed three times with d processing.

Next, the process proceeds to step S103, at which point the dimensions of the product 8a integral with the workpiece 8 are measured. After completing the shape processing, the ROM 9 in the control means 9
After the wire electrode 1 reaches the measurement position in accordance with the shape processing program stored in b, the wire positioning means 11 contacts and positions the wire electrode 1 and the workpiece 8 to measure the dimensions of the product 8a. Do. Then, the process proceeds to step S104, and as described later, when the measured dimension value falls within the allowable value, the ROM 9 in the control means 9 is controlled.
In accordance with the cut-off processing program stored in b, the cut-off processing is performed, and the shape of the product 8a is cut off from the workpiece 8 and separated.

<< Dimension Measurement Processing: See FIG. 3 >> Step S103 of FIG. 2 will be described in detail with reference to the flowchart of FIG. In step S201, the control unit 9
The X-axis drive motor 6 and the Y-axis drive motor 7 are driven in accordance with the shape processing program stored in the ROM 9b, and the processing table 4 mounted on the X-axis-Y-axis cross table 5 is moved. At this time, in order to move the wire electrode 1 and the workpiece 8 in a non-contact state, for example,
The offset value H1 used at the time of the first processing is set.

Next, the process proceeds to step S202, and stops at the measurement command position, that is, the position where Y = Y1. Prior to the start of the positioning operation by the wire positioning means 11, the coordinate values of each axis are once read and the current position X1 is read.
Is stored in the RAM 9c in the control means 9. The processing table 4 is moved in step S203. The movement at this time is a direction in which the wire electrode 1 approaches the product 8a integrated with the workpiece 8 in a direction opposite to the offset direction. In step S204, the wire electrode 1 is brought into contact with the product 8a (the gap is 0), and the workpiece 8 is stopped with respect to the wire electrode 1 when the wire electrode 1 reaches a position where the gap becomes 0.
Then, the coordinate value of each axis is read once and stored in the RAM 9c in the control means 9 as the current position X2.

Next, the process proceeds to step S205, and the processing table 4 is moved to the coordinate position before the start of the positioning operation in step S202 stored in the RAM 9c in the control means 9. In step S206, the processing table 4 is stopped at the coordinate position before the start of the positioning operation in step S202. At this point, the positioning operation by the wire positioning means 11 ends. Also, | X1−X2 | is calculated from the two stored coordinate values, and the coordinate value difference that is the calculation result is stored and displayed on the CRT display screen. If there is a next measurement command position in step S207, the processing from step S201 to step S207 is repeated. The next coordinate value read as the measurement command position is X
3, X4. If there is no measurement command position, the X-axis drive motor 6 and the Y-axis drive motor 7 are kept until the end of the shape machining program stored in the ROM 9 b in the control means 9.
Is driven to move the processing table 4. The dimensions of the product 8a integrated with the workpiece 8 are calculated from the coordinate values stored in the RAM 9c in the control means 9 in step S204.
It is displayed on the CRT display screen.

Next, the flow shifts to step S209 to compare the measurement result with the target value. That is, using the radius D of the wire electrode, K1 = | H1-D |-| X1-X2
|, K2 = | H1-D |-| X3-X4 |
K1 and K2 are compared with the allowable values, respectively. K1, K
If any of the two is smaller than the allowable value, the measurement is terminated. If both K1 and K2 are larger than the allowable values in step S209, the process proceeds to step S210, and additional processing such as correction processing is performed. Using the same shape processing program used for the shape processing, the offset value is corrected and additional processing is performed. However, in order to prevent excessive machining, the smaller of the correction amounts K1 and K2 is used. After the additional processing, the dimension is measured again, and if either K1 or K2 falls within the allowable value, the measurement is terminated.

FIG. 5 shows an example of a screen for designating a measurement location. Based on this screen, each measurement position in the processing shape corresponding to the shape processing program and step S209
And an allowable value used in the comparison are designated and input in advance. For example, when performing measurement at the position of Y = Y1 in the first shape, “1” is input in the item of the shape, “Y1” is input in the item of the measurement point Y, and an arbitrary allowable value “ A "is set. The same screen also displays the coordinate value difference calculated in step S206 as the measurement result and step S206.
The measured dimensions of the product 8a in the workpiece 8 calculated in 208 are displayed.

As described above, the wire electric discharge machining apparatus according to one embodiment of the present invention generates an electric discharge between the wire electrode 1 and the workpiece 8 to cause the workpiece 8 mounted on the machining table 4 to move. A storage means comprising a ROM 9b in a control means 9 for storing a shape program for performing wire electric discharge machining with the wire electrode 1, and a work piece 8 for the wire electrode 1 by contacting the work piece 8 with the wire electrode 1. The wire electrode 1 is moved with respect to the workpiece 8 in accordance with the shape program stored in the storage means, and the dimension of the workpiece 8 is measured using the wire positioning means 11. A dimension measuring means comprising a CPU 9a in the control means 9;
After wire EDM according to the shape program
The wire electrode 1 is moved with respect to the workpiece 8 before processing.
The shape profile corresponding to the measurement position specified in advance.
Coordinate values on the machining path of the ram and the wire positioning means 11
Measured by the dimension measuring means after the completion of the positioning operation.
CPU in the control means 9 for calculating a coordinate value difference from the coordinate value
The coordinate value difference calculating means 9a is provided.

Therefore, the shape processing of the workpiece 8
Integrated with the work piece 8 without later cutting off
Dimensions of various products can be measured. Also, the measurement position
Simply specify in advance the shape program corresponding to that position.
Coordinate values on the machining path of the ram and the wire positioning means 11
Coordinate value with coordinate value measured after completion of positioning operation
The difference is calculated, and the workpiece 8 is subjected to wire electric discharge machining.
The dimension measurement for the specified position is completed.

Further, the coordinate value difference calculated by the coordinate value difference calculating means is compared with a preset allowable value, and when the coordinate value difference exceeds the allowable value, the workpiece 8
Again, additional processing means including the CPU 9a in the control means 9 for performing wire electric discharge machining with the wire electrode 1
It is provided. Therefore, a product obtained by wire-discharge machining of the workpiece 8 is subjected to additional machining such as correction machining if necessary before the cut-off machining, so that dimensional accuracy at the designated position is guaranteed.

As described above, the workpiece 8 subjected to the electric discharge machining by the wire electrode 1 based on the shape program is mounted on the machining table 4 before the cut-off machining, and the shape corresponding to the designated measurement position is obtained. The coordinate value difference between the coordinate value on the machining path of the program and the coordinate value of the measured end face of the workpiece 8 is calculated. When the coordinate value difference exceeds the allowable value, additional processing by the wire electrode 1 can be performed again on the workpiece 8 before the cut-off processing. Therefore, in the product 8a cut off from the workpiece 8 by the wire electric discharge machining by the apparatus of the present embodiment, it is not necessary to perform the dimension measurement thereafter, and the dimension at the designated measurement position is within the predetermined dimension tolerance. Therefore, there is no need for additional work.

By the way, the storage means of the above embodiment generates a discharge between the wire electrode 1 and the workpiece 8 so that the workpiece 8 mounted on the processing table 4 is connected to the wire electrode 1 by the wire electrode 1. Although a shape program at the time of electric discharge machining is stored, other programs such as a machining condition program can be added when the present invention is implemented.

Further, the wire positioning means 1 of the above embodiment
Reference numeral 1 designates the positioning of the workpiece 8 with respect to the wire electrode 1 by bringing the workpiece 8 into contact with the wire electrode 1. In the case where the present invention is implemented, the wire electrode 1 and the workpiece 8 are positioned. It suffices if the relative position of 8 can be determined.

Then, the dimension measuring means of the above-described embodiment is adapted to operate the workpiece 8 in accordance with the shape program stored in the storage means.
In this case, the wire electrode 1 is moved with respect to and the dimension of the workpiece 8 is measured by using the wire positioning means 11. However, when the present invention is implemented, the relative position between the wire electrode 1 and the workpiece 8 is measured. The size of the workpiece 8 can be measured by the position.

Further, the coordinate value difference calculating means of the above embodiment is
The wire electrode 1 is moved with respect to the workpiece 8 before the cut-off processing after the wire electric discharge machining according to the shape program stored in the storage means, and the wire electrode 1 is moved on the processing path of the shape program corresponding to the measurement position specified in advance. And a CPU 9a in the control means 9 for calculating a coordinate value difference between the coordinate value of the first position and the coordinate value measured by the dimension measuring means after the completion of the positioning operation by the wire positioning means 11. Is to calculate a coordinate value difference between a coordinate value on a machining path of a shape program corresponding to a measurement position specified in advance and a coordinate value measured by the dimension measuring means after the positioning operation by the wire positioning means 11 is completed. I just need.

[0031]

As described above, the wire electric discharge machine according to the first aspect of the present invention generates an electric discharge between the wire electrode and the workpiece, and the workpiece mounted on the machining table is processed by the wire electrode. Storage means for storing a shape program when performing wire electric discharge machining, wire positioning means for positioning the work piece by bringing the work piece into contact with a wire electrode, and a wire for the work piece in accordance with the stored shape program Dimension measuring means for moving the electrode and measuring the dimension of the workpiece using the wire positioning means, so that the workpiece is integrated with the workpiece without cutting off the workpiece after shape processing. Dimensions of various products can be measured . Furthermore, according to the stored shape program
Workpiece before wire cut-off machining after wire electric discharge machining
The wire electrode is moved with respect to
Values and coordinates on the machining path of the shape program corresponding to the
Dimensions measured after positioning operation is completed by ear positioning means
Coordinate value to calculate the coordinate value difference from the coordinate value measured by the means
Equipped with a difference calculation means to specify the measurement position in advance
On the machining path of the shape program corresponding to that position
Positioning operation is completed by the coordinate values of
The coordinate value difference from the coordinate value measured later is calculated and
Dimension measurement of the product at the specified position
The effect is that the setting is completed.

[0032] The wire electric discharge machine according to the second aspect of the present invention has the following features.
In addition to the effect of 1, the calculated coordinate value difference is compared with a preset allowable value, and when the coordinate value difference exceeds the allowable value, the workpiece is again subjected to wire electric discharge machining by the wire electrode. The product obtained by wire electric discharge machining of the workpiece is subjected to additional machining, such as correction machining, if necessary, before cutting off to ensure dimensional accuracy at the specified position. This has the effect.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a wire electric discharge machine according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a wire electric discharge machining control procedure of the wire electric discharge machine according to one embodiment of the present invention.

FIG. 3 is a flowchart illustrating a dimension measurement processing procedure of the wire electric discharge machine according to one embodiment of the present invention.

FIG. 4 is an enlarged perspective view showing a dimension measurement state before cutting off a product of a workpiece in the wire electric discharge machine according to one embodiment of the present invention.

FIG. 5 is a view showing a screen in dimension measurement of the wire electric discharge machine according to one embodiment of the present invention.

FIG. 6 is a perspective view showing a schematic configuration of a conventional wire electric discharge machine.

FIG. 7 is a flowchart showing a procedure of a conventional wire electric discharge machining.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wire electrode 4 Processing table 5 X axis-Y axis cross table 6 X axis drive motor 7 Y axis drive motor 8 Workpiece 9 Control means 9a CPU 9b ROM 9c RAM 10 Measurement command position input means 11 Wire positioning means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23H 7/02 B23H 7/06

Claims (2)

(57) [Claims] 1. A storage means for generating a discharge between a wire electrode and a workpiece, and storing a shape program when the workpiece mounted on a machining table is subjected to wire electrical discharge machining by the wire electrode. A wire positioning means for positioning the workpiece by bringing the workpiece into contact with the wire electrode; and moving the wire electrode with respect to the workpiece according to the shape program stored in the storage means. And a dimension measuring means for measuring the dimension of the workpiece using the wire positioning means, and the shape program stored in the storage means.
Addition before wire cut-off machining after wire electric discharge machining
The wire electrode is moved with respect to the
Machining path of the shape program corresponding to the measured position
The coordinate values above and the positioning movement by the wire positioning means
After completion of the operation, the coordinate value measured by the dimension measuring means
A wire electric discharge machine comprising: a coordinate value difference calculating means for calculating a coordinate value difference . 2. The method according to claim 1, wherein the coordinate value difference calculated by the coordinate value difference calculation means is compared with a preset allowable value, and the coordinate value difference exceeds the allowable value. Te again, characterized by including the additional machining means for implementing the wire electric discharge machining by the wire electrode according to claim 1
2. The wire electric discharge machine according to claim 1.