JPH0451941Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a wire-cut electric discharge machining apparatus, and is particularly concerned with improving a wire-cut electric discharge machining apparatus suitable for machining a workpiece whose thickness changes in the part to be machined. It is something.

[Prior art]

Conventionally, when processing a workpiece whose thickness changes, as shown in FIG. This prevents the wire guide 53 from interfering with the upper surface of the workpiece 59.

In addition, in FIG. 5, 522 is a servo motor for lifting, 524 and 544 are pulleys, and 526 and 54 are
6 is a power supply die, and 56 is a wire.

As for such a lifting device 52, for example, Japanese Utility Model Application Publication No. 56-72628 discloses one that is manually adjusted, and Japanese Patent Application Laid-Open No. 56-76332 discloses a device that is automatically adjusted by NC control using a motor. something is disclosed.

[The problem that the idea aims to solve]

However, in order to change the distance between the upper wire guide 53 and the lower wire guide 54 using the lifting device 52, the conventional wire cut electric discharge machining apparatus 50 measures the thickness of the workpiece 59 in advance and uses the data. There was a problem in that it required input into the NC control device, making the operation extremely complicated.

In addition, if this operation is neglected or incorrectly performed, there is a problem that interference with the workpiece occurs and machining accuracy deteriorates.

Therefore, in the present invention, the distance between the wire guide and the workpiece whose thickness changes is controlled to be constant.
The purpose is to automatically prevent the wire guide from interfering with the workpiece.

[Means to solve the problem]

Therefore, in the present invention, one wire guide is fixed below the base on which the work is placed, and the other wire guide is provided above the base so that it can be raised and lowered by a drive means via a support member. In addition, a wire cut discharge is provided in which a discharge wire is stretched between the one wire guide and the other wire guide, and the work is cut by the discharge wire by causing discharge between the discharge wire and the work. In the processing device, around the other wire guide of the support member,
A plurality of sensors are provided at predetermined intervals to measure the distance to the workpiece, and further, the distance between the other wire guide and the workpiece is determined by the output signal of the sensor whose detected output of the measured value has changed. A drive control means is provided for controlling the drive means so as to maintain the same value.

[Effect]

According to the above-mentioned means, the distance to the workpiece is detected by a plurality of sensors provided around the other wire guide of the support member located above the workpiece, and among these sensors, the detection output of the measured value is The drive control means controls the drive means based on the detection signal of the sensor in which the change has occurred, to raise and lower the other wire guide, and to maintain the distance between the other wire guide and the workpiece at a predetermined value at all times. This results in
The other wire guide pulls the discharge wire along with one wire guide while following the shape of the workpiece.
Perform electrical discharge machining.

〔Example〕

Embodiments of the present invention will be described below based on the accompanying drawings.

1 to 4 show an embodiment of the present invention, in which FIG. 1 is a front view showing a schematic configuration of a wire-cut electric discharge machining device, and FIG. 2 is a front view showing the installed state of the sensor. Arrow view along the line, 3rd
The figure is a diagram conceptually showing a system for controlling the raising and lowering of the wire guide, and FIG. 4 is a schematic diagram showing the system configuration of the NC control device together with a servo motor.

The wire cut electric discharge machining apparatus 1 includes a pair of wire guides 2 and 3, a discharge wire 4, a sensor 6,
It is composed of a servo motor 8 as a drive means, a drive control means 9, and a base 10.

A pair of wire guides 2 and 3 are used to stretch the discharge wire 4, and one wire guide 2 is fixed to a support member 22 provided below a base 10 on which a workpiece W is placed. .

Further, above the base 10, the other wire guide 3 is provided so as to be movable up and down by a servo motor 8. That is, the wire guide 3 is attached to a support member 81 attached to the lower end of the servo motor 8.

The sensor 6 is for measuring the distance between the wire guide 3 and the upper surface of the workpiece W, and is a non-contact sensor such as an ultrasonic sensor.

The sensor 6 includes an ultrasonic transmitter sensor 62 and an ultrasonic receiver sensor 64, which are transducers, forming a pair, and a supporting member 81 as shown in FIG.
They are attached at four equally spaced locations around the wire guide 3.

Thereby, it is possible to detect a change in the measurement data of at least one of the sensors 6 attached at four locations, thereby detecting a change in the distance to the workpiece W, that is, a change in the thickness of the workpiece W.

The drive control means 9 is for controlling the servo motor 8 that raises and lowers the wire guide 3, and the servo motor 8 is driven by the system configuration shown in FIG.

That is, this drive control means 9 includes an ultrasonic sensor test board transmitting circuit 91, an ultrasonic sensor test receiving circuit 92, a measurement processing circuit 93, and an NC control device 94.

The ultrasonic sensor test board transmitting circuit 91 is for operating the transmitting side sensor 62 with a voltage of 40 kHz and 28 V, and is driven by a CMOS 40 kHz oscillation circuit to generate a 28 V rectangular wave with both amplitudes.

The ultrasonic sensor test receiving circuit 92 is for amplifying the weak radio waves from the receiving sensor 64 to a TTL level using an OP amplifier.

The measurement processing circuit 93 is for counting the time from transmitting ultrasonic waves to receiving them and calculating the distance using a microcomputer, and is composed of a known measurement processing circuit.

The NC control device 94 is for outputting a control signal to the servo motor 8, and receives the position command signal IPS from the measurement processing circuit 93 as shown in FIG. 4, and outputs a drive signal OPS to the servo motor 8. It is something.

The position command feedback signal FBS from the position detector 945 fixed to the lifting head 944 to which the servo motor 8 is attached is also input to the deviation counter 941 of the NC control device 94 to which the position command signal IPS is input. There is.

Note that 942 is a D/A converter, 943 is a power amplifier, 82 is a ball screw, and 83 is a magnet scale.

To explain the operation of the embodiment according to the above configuration, first, under normal machining conditions where there is no change in the thickness of the workpiece W, the other wire guide 3 of the wire-cut electric discharge machining apparatus 1 maintains a predetermined distance from the workpiece W. is stopped in the state.

At this time, by moving the base 10 on which the workpiece W is placed in a horizontal plane, the workpiece W is subjected to wire-cut electric discharge machining according to a predetermined machining locus of the workpiece W.

Next, when the thickness of the workpiece W reaches a position where it changes, the detection output of at least one of the four sensors 6 provided at the lower end of the wire guide 3 is changed.

As a result, the output signal of the sensor 6 that has caused a change is input to the measurement processing circuit 93 of the drive control means 9, and the output signal from the measurement processing circuit 93 causes the output signal to be changed.
The NC control device 94 controls the servo motor 8 to move the other wire guide 3 up and down.

In this way, the other wire guide 3 and the work W
The drive control means 9 detects the distance from
The servo motor 8 is controlled by the servo motor 8 to raise and lower the other wire guide 3 so that the distance from the workpiece W is constantly maintained at a predetermined value. Electric discharge machining is performed by pulling the electric discharge wire 4 together with the electric discharge wire 2 .

Therefore, during electrical discharge machining, the other wire guide 3
Interference with the workpiece W can be reliably prevented.

Furthermore, since a plurality of sensors 6 are provided around the other wire guide 3 of the support member 81 at predetermined intervals, the plurality of sensors 6 can be used even when the cutting direction of the workpiece W by electrical discharge machining is not only in one direction but in any direction. 6
Since the distance to the workpiece W can be detected by at least one of the sensors 6, interference between the other wire guide 3 and the workpiece W can be reliably prevented even when the processing direction of the workpiece W changes.

Furthermore, since electrical discharge machining can be performed while constantly measuring the thickness of the workpiece W, it is possible to greatly improve the accuracy of maintaining the workpiece W and the other wire guide 3 at a predetermined distance, and it is possible to There is no need to measure the workpiece W in advance before machining, and the machining process can be shortened.

Furthermore, since there is no need to input data for raising and lowering the other wire guide 3 into the machining program, the machining program can be easily created without considering changes in the thickness of the workpiece W.

Although the present invention has been described above based on specific embodiments, it is not limited thereto, and various embodiments can be considered by those skilled in the art within the scope of the claims for utility model registration.

For example, although an ultrasonic sensor is used as the sensor in the above embodiment, an optical sensor or a mechanical sensor may be used instead of an ultrasonic sensor.

Further, although the sensor is provided on the support member attached to the servo motor that is the driving means, it may be provided on the other wire guide itself.

[Effect of idea]

As described above, the present invention detects the distance between the other wire guide and the workpiece using a sensor, and when a change occurs in the detection signal, the drive control means controls the drive means based on the detection signal. Since the other wire guide is raised and lowered to perform electrical discharge machining while maintaining the distance to the workpiece at a predetermined value, it is possible to reliably prevent the other wire guide from interfering with the workpiece during electrical discharge machining. can.

In addition, since a plurality of the sensors are provided at predetermined intervals around the other wire guide of the support member, the cutting direction of the workpiece by electric discharge machining is not limited to only one direction.
In any direction, since the distance to the workpiece can be detected by at least one of the plurality of sensors, interference with the workpiece can be reliably prevented even when the processing direction of the workpiece changes.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the present invention, in which FIG. 1 is a front view showing a schematic configuration of a wire-cut electric discharge machining device, and FIG. 2 is a front view showing the installed state of the sensor. Arrow view along the line, 3rd
The figure conceptually shows the system for controlling the elevation of the wire guide, Figure 4 is a schematic diagram showing the system configuration of the NC control device together with the servo motor, and Figure 5 is the schematic diagram of the conventional wire-cut electrical discharge machining device. FIG. 1... Wire cut electrical discharge machining device, 2... One wire guide, 3... Other wire guide, 4
... discharge wire, 6 ... sensor, 8 ... servo motor (drive means), 9 ... base, 10 ... drive control means, W ... work.

Claims (1)

[Claims for Utility Model Registration] One wire guide is fixed below a base on which a workpiece is placed, and the other wire guide is movable up and down above the base by a driving means via a support member. A discharge wire is stretched between the one wire guide and the other wire guide, and the workpiece is cut by the discharge wire by causing discharge between the discharge wire and the workpiece. In the wire-cut electrical discharge machining apparatus, the support member includes a wire guide around the other wire guide,
A plurality of sensors are provided at predetermined intervals to measure the distance to the workpiece, and further, the distance between the other wire guide and the workpiece is determined by the output signal of the sensor whose detected output of the measured value has changed. A wire cut electric discharge machining apparatus characterized in that a drive control means is provided for controlling the drive means so as to maintain the wire cut electric discharge machining device at a certain value.