JPH03251321A - Electrical discharge machine device - Google Patents

Abstract

PURPOSE:To measure inclination angle at high speed with high accuracy, by moving a measuring means along a reference axis (X-axis in this execution example), measuring the gap between the moving body to be worked or an electrode and the measuring means in the continued state timely, computing the inclination angle based on this measurement result, and composing it so as to perform the correction. CONSTITUTION:During the movement of a measuring means 8 by a moving means, the result of the distance between the body 1 to be worked or an electrode and the measuring means 8 being measured in continuation timely by the measuring means 8 is held by a holding means 44. The inclination of the body 1 to be worked or electrode from the reference axis is computed by an arithmetic means 45 based on the measurement result held by the holding means 44. The correction computation which rotates the coordinate system by the reference axis is performed by a correction arithmetic means 43 based on the inclination computed by this inclination arithmetic means 45.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to electrical discharge machining equipment.

In particular, it relates to electrical discharge machining equipment that can correct and correct the inclination of the workpiece or electrode from the reference axis when the workpiece or electrode is attached to the reference axis for moving the workpiece and electrode relative to each other. be.

[Prior Art] Generally, in an electrical discharge machining device, a workpiece and an electrode are placed facing each other, and a voltage is applied between the workpiece and the electrode while moving the two relatively to cause electrical discharge. Processing is in progress.

The relative movement between the workpiece and the electrode is controlled by an NC device. The control is based on the control program of this NC device.

The machine program for moving the workpiece and the electrode relative to each other is created based on the X, Y, and Z axes, which are reference axes.

By the way, in such an electric discharge machining apparatus, when the workpiece and the electrode are arranged to face each other, the workpiece or the electrode may be arranged at an angle with respect to the reference axis. In this case, when machining is performed based on the machine program, the workpiece may be machined at a position deviated from a predetermined position.

As a conventional technique that improves these drawbacks, Japanese Patent Application Laid-open No. 62
-287933 publication or JP-A-60-259375
There was something shown in the issue.

These conventional techniques disclose techniques for correcting when a workpiece is mounted at an angle, but in all of these, the correction is performed based on measurement points at several locations.

FIG. 5 and FIG. 6 are diagrams for explaining the prior art. In Fig. 5, (1) is the workpiece,
(121 is the reference surface of the workpiece, (2) is the measuring head, (3)
(4) is the X-axis head, (5) is the bed part of the electrical discharge machining device, (4) is the
) shows the Y-axis head, (6) shows the Z-axis head, and (7) shows the surface plate with electrodes attached. X, Y, Z.

The axes constitute mutually perpendicular coordinates, and this coordinate system serves as a reference axis. In addition, the X-axis, Y-axis and Z-axis heads (
4), (5), and (6) are driven along the X-axis, Y-axis, and Z-axis by an NC control device (not shown). Accordingly, the NC control device moves each head (41 (51 (6)) to predetermined coordinates of the X, Y, and Z axes and performs electrical discharge machining using the machining program created based on the reference axes.

In FIG. 6, (411 is a detection device, (42
) is a tilt calculation device that calculates the tilt angle, (431 is a correction calculation device that performs a coordinate rotation calculation that rotates the X, Y orthogonal coordinate system, and arrows (21) to (24) are the measuring stylus (2).
2 shows the operation of the probe (2) for measuring how much the reference plane (12) of the workpiece (1) is tilted from the X-axis.

In what is shown in this prior art, the Kani program is the reference axis. Because it is created based on the X, Y, and Z axes,
When attaching a workpiece, it is necessary to perform positioning along the X-axis or Y-axis, attach the workpiece, and process a predetermined position of the workpiece. However, this positioning...

Since this involves extremely complicated work, it has been designed so that the correction can be made even if the two parts (11) are mounted at an angle with respect to the X-axis, as shown in FIG.

Next, this correction will be explained based on FIGS. 5 and 6.

First, the inclination angle between the reference surface (12) of the workpiece (1) and the reference axis X-axis of the electrical discharge machining apparatus is measured.

In this case, as shown in Fig. 5, the probe (2) is attached to the electrode mounting surface plate (7), and the probe (2) and the workpiece (11
The relative position of the sensor is detected by electrical contact.

At this time, the operations shown in arrows (21) to (24) in Fig. 6 are performed to determine the degree of inclination between the reference surface (12) of the workpiece (1) and the reference axis X-axis of the electrical discharge machining device. Measure. Specifically, the movement indicated by the arrow (21) is a movement movement in the Y-axis direction in order to bring the probe (2) into electrical contact with the reference surface (12) of the workpiece (1) and position the end face. be. (25
), the contact point (2) is brought to the reference surface (
12) and perform end face positioning. At this time, the X and Y coordinate values of point (25) are (o.

yz). Next, arrow (22) is the dissociation operation.

An arrow (23) indicates an operation of x0 movement in the X-axis direction.

Next, the arrow (24), like the arrow (21), is a moving operation in the Y-axis direction to position the end face of the probe (2) on the reference surface (12) of the workpiece (lj). By the operation, the probe (2) performs end face positioning with the reference surface (12) by electrical contact at the point (261). At this time, the X and Y coordinate values of the point (26) are expressed as ).These series of measurement results are detected and held by the detection device (41). Based on these results, the degree of inclination between the reference plane (12) of the workpiece (1) and the X-axis of the electrical discharge machining device is determined. Find the Y-axis coordinate y for the X-axis coordinate X.

y3 - y2, and the rotation angle θ at this time is given by O θo = arct, an
Perform calculations based on formulas. Based on this calculation result, the correction calculation device (43) calculates the coordinate rotation of the XY orthogonal coordinate system. FIG. 7 shows the principle of coordinate rotation. The electric discharge machining apparatus has a reference in which the X and Y axes are perpendicular to each other, but as described above, the workpiece (1) is at an angle of θ with respect to the X axis. When installed at an angle of θ with respect to the XY orthogonal coordinate system,
. If we define the X13' rectangular coordinate as a new coordinate system with an angle of The relationship is given by the equations ■ and ■.

Xn ”XnCO3θ6-ynSllll Oo”
'■Yn=XnS1nθ. +ynCO8θ.・
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The control section.

Based on this calculation result, the X-axis head (14) of the electrical discharge machine is moved along the guideway of the X-axis reference axis, and the Y-axis head (5) is moved along the Y-axis. The electrode is moved by Yn along the guideway of the reference axis, the electrode is moved to point P, and a predetermined electrical discharge machining is performed at the desired position.

[Problems to be Solved by the Invention] FIG. 8 is a diagram for explaining the problems of the prior art. In the figure, the second curve (11) is an enlarged view of the surface texture of the reference surface (12) of the workpiece fil.

The reference surface (12) is usually a polished surface, but as shown in Figure 9,
It has a small rough surface and large undulations for 5 laps.
In some cases, they also have deep scars (14).

Therefore, the inclination of the reference plane (12) with respect to the reference axis X-axis is a straight line (13), and the inclination angle is θ. For example, if the measurement points are at the valleys and peaks of the undulation, as in (311f3zl), the inclination angle will be measured as 01, which is smaller than the true value of 0°.

In addition, when the measurement points are the peaks and valleys of the undulations as shown in (31 (34)), the inclination angle is measured as θ-, which is larger than the true value Oo, and there is a problem that accurate correction cannot be performed. there were.

According to Japanese Patent Publication No. 1259325, a proposal has been made to solve the above-mentioned problems by [detecting the position coordinate values of three or more end points with respect to the end face of the workpiece]. , this method is not sufficient. In other words, when detecting three or more end points, it is necessary to decide in advance which points to adopt as detection points, for example, 5 points every r2 mm. However, What are the properties of the end surface of the workpiece?

As shown in Figure 8, the angle is irregular, and of course it is impossible to predict the end face properties before measurement, so the five points every r 2 mm are used as detection points to detect the inclination angle with high precision. There is no guarantee that it will be sufficient.

Furthermore, even if the number of end points to be detected is increased to five or more, the same problem basically remains.

Furthermore, when detecting multiple points, there is also a problem of 9th order. That is,
As shown in Fig. 6, end point detection is performed by an end face positioning operation in which the measuring head (2) electrically detects contact with the reference surface (12) of the workpiece (1), but in practice it is 1986-
This is carried out by a series of operations as described in FIG. 6 of Japanese Patent No. 259325 and its operation description. Therefore,
To detect multiple points.

If this series of operations is performed many times, there is a big problem in that it takes a lot of time to detect the inclination.

This invention was made to solve the above-mentioned problems, and even if the reference surface of the workpiece to be measured has undulations or deep scratches, the reference surface and the reference axis can be easily aligned. It is an object of the present invention to provide an electric discharge machining apparatus that can measure the inclination angle of a metal plate with high precision and high speed, and can perform electric discharge machining at an accurate position.

[Means for Solving the Problems] The electrical discharge machining apparatus according to the present invention includes a measuring means for measuring the distance to the workpiece or the electrode, and a reference axis for relatively moving the workpiece and the electrode. a moving means for moving the measuring means, and while the measuring means is being moved by the moving means;
A holding means for holding the results of time-continuously measuring the distance between the workpiece or electrode and the means on both sides using the measuring means; An inclination calculation means for calculating an inclination; and a correction calculation means for performing a correction calculation for coordinate rotation of the coordinate system based on the reference axis based on the inclination calculated by the inclination calculation means.

It is equipped with the following.

Further, another electrical discharge machining apparatus according to the present invention includes a head portion provided with a one-rotation portion, a workpiece or an electrode attached to the one-rotation portion, and a measuring means for measuring the distance between the workpiece or the electrode; a moving means for moving a measuring means along a reference axis for relatively moving the workpiece and the electrode;
A holding means for holding the results of time-continuously measuring the distance between the workpiece or the electrode and the four measuring means by the measuring means while the measuring means is being moved by the moving means; and an inclination calculation means for calculating the inclination of the workpiece or the electrode from the reference axis based on the reference axis.

Based on the inclination determined by the inclination calculation means, the rotating part is rotated Φi, and the rotation part Jl (control means for correcting the inclination of the workpiece or the electrode with respect to the stem axis).

It is equipped with the following.

[Operation] In this invention, the distance between the measuring means and the workpiece or electrode is measured over time while the moving means is moving the measuring means along the reference axis, and continuous measurement values are obtained for 9 hours. is used to calculate the tilt angle.

Further, in another invention, a rotating part to which a workpiece or an electrode is attached is rotated based on the calculation result of the inclination angle (12).

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the same parts as those of the conventional device shown in FIG. 5 are shown. In this embodiment, unlike the conventional device shown in FIG.
A displacement measuring means (8) for measuring displacement is attached. In Figure 2, the displacement measuring means (8) is moved along the reference axis (X-axis in this example) as shown by the arrow (27), and the measuring rod (9) of the displacement measuring means (8) is When the gap is large, it shows expansion, and when the gap is narrow, it shows shrinkage.

A converter (44) constituting the holding means converts and holds the displacement amounts of this expansion and contraction in the form of, for example, an analog voltage, and outputs the same. (45) is a tilt calculation device that calculates the tilt angle between the reference axis X-axis and the reference surface (12) of the workpiece (1) from this analog output voltage.

(43) is a correction calculation device having a coordinate rotation function for rotating the XY orthogonal coordinate system, which is the same as the conventional device shown in FIG.

Next, the operation of this embodiment device will be explained. That is,
The amount of displacement measured by the displacement measuring means (8) is measured by the converter (44).
) is converted to an analog voltage value by the curve (1
The output waveform will be as shown in 5).

This output waveform (15) indicates that the reference surface (12) of the workpiece has fine surface roughness, large periodic undulations, and in some cases, deep scratches (14). ing.

Next, the slope calculation device (45) approximates the output waveform (15) to a straight line (16) using, for example, the method of least squares, and
The inclination angle θ between the axis and the reference plane (12). Calculate. The correction calculation device (43) performs the same calculation as the calculation device (43) shown in FIG. 6, and as shown in FIG. Coordinate form (xn
, yn).

Then, based on this calculation result, the NC control device uses the X-axis head (4
) along the guideway of the Z-axis reference axis. , move the Y-axis head (5) along the guideway of the Y-axis reference axis Yn
, and the electrode is moved to point P.

In this invention, the measuring means is moved along the reference axis (Z-axis in this example), and the gap between the moving workpiece and the workpiece is output as a displacement amount in a temporally continuous manner, and the output waveform is A straight line is approximated using a regression analysis method such as the least squares method. In this embodiment, the output of the displacement measuring means (8) is converted into an analog voltage by the converter (44), but the converter (44) converts the output of the displacement measuring means (8) into an analog voltage. ). The displacement measuring means (8) may be any device capable of measuring displacement or distance, such as a laser length measuring device, an ultrasonic length measuring device, or an eddy current gap sensor.

FIG. 4 shows another embodiment of the present invention, in which an electrode or a workpiece having a length of τ1, which is provided on the head portion and is attached to the rotating portion;
A technique will be described in which the inclination angle of a reference axis (Z-axis or Y-axis) is detected, the rotation axis C-axis of the one-rotation section is rotated, and the inclination is corrected.

In FIG. 4, the same reference numerals as in the embodiment of FIG. 1 indicate the same parts. In the figure, (511 is a rotating part provided in the Z-axis head part, and the C-axis rotates the electrode or workpiece attached to this rotating part (51) around the Z-axis head part (6). (52) indicates the electrode or the workpiece. Also, the workpiece mounting surface plate on which the workpiece is attached.
- Displacement measuring means (8) for measuring displacement is installed.

Next, the operation of this embodiment will be explained. That is, as in FIG. 2, the displacement measuring means (8
) to move. This movement actually involves the X-axis head (
The movement of step 4) causes the electrode side to move, thereby relatively moving the displacement measuring means (8). The measuring rod part (9) of the displacement measuring means (8) expands when the gap is large and contracts when the gap is narrow. The amount of displacement measured by this measuring means (8) is converted into an analog voltage value (16) by a converter (44) constituting the holding means, and a waveform as shown in the curve (15) in Fig. 3 is maintained. and output it. Next, the slope calculation device (45)
The output waveform (15) is approximated to a straight line (16) using, for example, the method of least squares, and the inclination angle θ between the electrode or the workpiece and the reference axis X is determined. Calculate. This calculation result θ. Based on
The control means rotates the C-axis, which is the rotating part (51), at 10. Rotate it a lot. Thereby, the electrode or the workpiece is corrected so that it becomes parallel to the reference axis X-axis. In this embodiment, a series of angle measurement operations are performed in one go, making it possible to measure angles with high precision.
This has the effect of being able to correct the tilt angle by rotating the shaft.

[Effects of the Invention] In the device of the present invention, the measuring means is moved along the reference axis (Z-axis in this example), and the gap between the moving workpiece or electrode and the measuring means is made to be continuous in time. Since the tilt angle can be calculated and corrected based on the measurement results, the tilt angle can be measured quickly and with high precision without complicated work, and accurate correction can be made. This has the effect of allowing highly accurate electrical discharge machining.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of an electrical discharge machining apparatus according to the present invention, FIG. 2 is a diagram for explaining a method of measuring the inclination between a reference plane and a reference axis according to the present invention, and FIG. FIG. 4 is a graph diagram showing the measurement results by the measuring means and the calculation method of the inclination, and FIG. 4 is a perspective view showing another embodiment of the electric discharge machining apparatus according to the present invention. FIG. 5 is a perspective view of the conventional device, FIG. 6 is a diagram corresponding to FIG. 3 in the conventional device, FIG. 7 is a diagram for explaining the rotation of the coordinate system, and FIG. 8 is a diagram for explaining the drawbacks of the conventional device. This is a diagram for In the figure, (1) is the workpiece, (8) is the measuring means, (12
1 is the reference plane, (44) is the holding means, f45) is the tilt dripping means, (431 is the correction calculation means, (7) is the number of electrodes 1 surface plate, and (51) is the rotating part. Note that in Figure 9 Identical or equivalent parts are given the same reference numerals.

Claims (2)

[Claims] (1) A measuring means for measuring the distance to the workpiece or the electrode; A moving means for moving the measuring means along a reference axis for relatively moving the workpiece and the electrode; a holding means for holding results of time-continuously measuring the distance between the workpiece or the electrode and the measuring means by the measuring means while the measuring means is being moved by the means; an inclination calculation means for calculating the inclination of the workpiece or the electrode from the reference axis based on the measurement results held; and correction for coordinate rotation of the coordinate system based on the reference axis based on the inclination calculated by the inclination calculation means. An electrical discharge machining device characterized by comprising: a correction calculation means for performing calculations; (2) a head section provided with a rotating section; a workpiece or electrode attached to the rotating section; a measuring means for measuring the distance between the workpiece or the electrode; and a distance between the workpiece and the electrode. a moving means for moving the measuring means along a reference axis for relatively moving the measuring means; holding means for holding results of time-continuously measured distances; and tilt calculation means for calculating the inclination of the workpiece or electrode from the reference axis based on the measurement results held by the holding means; An electrical discharge machining apparatus comprising: control means for rotating the rotating section based on the inclination calculated by the inclination calculating means and correcting the inclination of the workpiece or the electrode with respect to the reference axis.