JP2003089016A - Wire-cut electric discharge machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire-cut electric discharge machine capable of giving an accurate and stable tension to a wire. SOLUTION: The wire-cut electric discharge machine 1 to apply a discharge machining to a work 3 while running the wire 2 given a tension, is equipped with a tension arm 36 turning round a fulcrum with an energizing force of a spring 39 for giving a tension to the wire 2 heading to the work 3, the spring 39 to energize the arm 36 in its rotating direction, a potentiometer 37 to sense the rotating angle of the arm 36, and a controller 6 to make a feedback control of the feeding speed of the wire 2 so that the rotating angle of the arm 36 approaches the target value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a wire-cut electric discharge machine for performing electric discharge machining on a workpiece while moving a wire.

[0002]

2. Description of the Related Art Generally, a wire-cut electric discharge machine moves a wire and a work relative to each other while running the wire while applying a predetermined tension to the wire, and applies a predetermined electric discharge machining voltage to a gap between the wire and the work. Then, the work is processed.

In order to improve the processing accuracy and surface quality, it is necessary to apply accurate and stable tension to the wire.

Conventionally, as a means for automatically adjusting the tension of the wire, for example, Japanese Patent Laid-Open No. 2000-246545 discloses a tension for feedback-controlling the drive torque of a pulley for feeding the wire in accordance with the detected tension of the wire. A device is disclosed.

[0005]

However, in such a conventional tension device, there is a problem that it is difficult to apply an accurate and stable tension to the wire because an excessive inertial load due to the inertial force acts on the pulley. there were.

The present invention has been made in view of these problems, and an object of the present invention is to provide a wire cut electric discharge machine which can apply an accurate and stable tension to a wire.

[0007]

The first invention is applied to a wire-cut electric discharge machine for performing electric discharge machining on a workpiece while running a wire to which tension is applied.

An upstream side feed mechanism for feeding the wire to the work, a downstream side feed mechanism for feeding the wire from the work, a tension arm for rotating the wire around the fulcrum and applying tension to the wire toward the work. A biasing mechanism that biases the tension arm in its rotation direction, a detection unit that detects the rotation angle of the tension arm, and a wire feed mechanism that moves the tension arm so that the rotation angle of the tension arm approaches a target value. A control means for feedback controlling the feed speed is provided.

According to a second aspect of the present invention, in the first aspect of the present invention, a feeding mechanism for feeding the wire, an auxiliary tension arm for applying a tension to the wire which is rotated around the fulcrum toward the upstream side feeding mechanism, and the auxiliary tension are provided. A biasing mechanism that biases the arm in its rotation direction, a detection unit that detects the rotation angle of the auxiliary tension arm, and a wire feeding speed by the wire feeding mechanism so that the rotation angle of the auxiliary tension arm approaches a target value. And a control means for performing feedback control.

A third invention is characterized in that, in the first or second invention, a bobbin for winding a wire is provided as a downstream side feeding mechanism.

[0011]

According to the first aspect of the present invention, when the wire is running, the fluctuation of the tension applied to the wire is absorbed by the change of the rotation angle of the tension arm, and excessive tension is applied to the wire. To be prevented.

When the speed at which the wire is fed by the downstream side feed mechanism changes and the tension applied to the wire changes, the rotation angle of the tension arm changes. The tension applied to the wire is returned to a predetermined value by feedback-controlling the wire feeding speed by the upstream feeding mechanism so that the rotation angle of the tension arm approaches the target value.

In this way, accurate and stable tension is applied to the wire, and the electric discharge machining accuracy for the work is improved.

According to the second aspect of the invention, when the feed rate of the wire by the upstream side feed mechanism is changed and the tension applied to the wire is changed, the rotation angle of the auxiliary tension arm is changed. The tension applied to the wire is returned to a predetermined value by feedback-controlling the wire feeding speed of the wire feeding mechanism so that the rotation angle of the auxiliary tension arm approaches the target value.

In this way, accurate and stable tension is applied to the wire, and the electric discharge machining accuracy for the work is improved.

According to the third invention, since the wire is wound around the bobbin, there is no fear that the used wire will be scattered.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, a wire-cut electric discharge machine 1 moves a wire 2 and a work (workpiece) 3 relative to each other while moving the wire 2 while applying a predetermined tension to the wire 2. A predetermined voltage for electric discharge machining is applied to the gap between the work 3 and the work 3 to cut the work 3.

A bobbin 4 for winding the wire 2 is provided as a downstream side feeding mechanism for feeding the wire 2 from the work 3. By winding the wire 2 around the bobbin 4, there is no fear that the wire 2 will be scattered after use.

The running speed of the wire 2 is determined by the rotating speed of the winding bobbin 4. The winding bobbin 4 is a motor 5
The rotation speed of the motor 5 is controlled by the controller 6.

As the downstream feeding mechanism, a feed pulley for discharging the wire 2 may be provided instead of the winding bobbin 4 so that the used wires 2 may be stacked.

The tension of the wire 2 is automatically adjusted by the feeding tension device 10 and the servo tension device 30.

The servo tension device 30 includes a feed pulley 31, guide pulleys 32 to 35, and a tension arm 36.
Equipped with. The rotation angle range of the tension arm 36 is restricted by the stopper 42. Further, a felt 8 for inserting the wire 2 is provided between the guide pulley 15 and the feed pulley 31.

The tension arm 36 is rotatably supported with its base end serving as a fulcrum, and has a guide pulley 3 at its tip.
4 is attached, and a spring (biasing mechanism) is installed in the middle
39 are connected. That is, the spring force of the spring 39 acts on the wire 2 in accordance with the rotation angle of the tension arm 36, and a predetermined tension based on this spring force is applied.

The end of the spring 39 is movable by the tension adjusting mechanism 38, and the controller 6 drives the tension adjusting mechanism 38 to continuously change the magnitude of the tension acting on the wire 2. As a result, the accuracy and degree of freedom of tension control is improved.

The wire 2 is wound around the feed pulley 31 and the guide pulley 32, and is fed by the rotation of the feed pulley 31. The feed pulley 31 is driven by the motor 41. The rotation angle of the tension arm 36 is detected by the potentiometer 37, and the controller 6 feedback-controls the rotation speed of the motor 41 so that the detected rotation angle of the tension arm 36 approaches a target value.

The feeding tension device 10 comprises a feeding pulley 11, guide pulleys 12 to 15 and an auxiliary tension arm 16.

The auxiliary tension arm 16 is rotatably supported with its base end as a fulcrum, a guide pulley 14 is attached to the tip thereof, and a spring 19 is connected in the middle thereof. That is, the spring force of the spring 19 acts on the wire 2 in accordance with the rotation angle of the auxiliary tension arm 16, and a predetermined tension based on this spring force is applied.

The end of the spring 19 is movable by the tension adjusting mechanism 18, and the controller 6 drives the tension adjusting mechanism 18 to continuously change the magnitude of the tension acting on the wire 2. As a result, the accuracy and degree of freedom of tension control is improved.

The delivery pulley 11 provided as a delivery mechanism is driven by a motor 21. A potentiometer 17 is provided as a means for detecting the rotation angle of the auxiliary tension arm 16, and the controller 6 feedback-controls the rotation speed of the motor 21 so that the detected rotation angle of the auxiliary tension arm 16 approaches a target value. To do.

The operation of the embodiment of the present invention configured as described above will be described below.

When the wire 2 is running, the winding speed (winding amount) of the winding bobbin 4 changes and the wire 2
When the tension applied to the arm fluctuates, the rotation angle of the tension arm 36 changes. As a result, the change in tension is absorbed by the change in the rotation angle of the tension arm 36,
Excessive tension is prevented from being applied to the wire 2.

A change in the rotation angle of the tension arm 36 is detected by the potentiometer 37, and the controller 6 controls the rotation speed of the motor 41 so that the rotation angle of the tension arm 36 returns to a predetermined angle, and the feed pulley is rotated. Three
The drawing speed (drawing amount) of the wire 2 by 1 is controlled so as to be balanced with the winding speed (winding amount) of the winding bobbin 4. As a result, the tension arm 36
The rotation angle of is returned to a predetermined angle, and the tension applied to the wire 2 is returned to a predetermined value.

When the withdrawal speed (withdrawal amount) of the feed pulley 31 changes during the traveling of the wire 2, the rotation angle of the auxiliary tension arm 16 changes. A change in the rotation angle of the auxiliary tension arm 16 is detected by the potentiometer 17, and the controller 6 controls the rotation speed of the motor 21 so that the rotation angle of the auxiliary tension arm 16 returns to a predetermined angle, and the delivery pulley 11 is moved. The feeding speed (feeding amount) of the wire 2 is controlled so as to be balanced with the winding speed (winding amount) of the winding bobbin 4. As a result, the auxiliary tension arm 1
The rotation angle of 6 returns to a predetermined angle, and the tension applied to the wire 2 sent to the feed pulley 31 is returned to a predetermined value.

In this way, the work 3 is moved by the feeding tension device 10 and the servo tension device 30.
An accurate and stable tension is applied to the wire 2 fed to the wire. As a result, the accuracy of the electric discharge machining for the work 3 is improved.

An air cylinder may be provided instead of the spring as a biasing mechanism for biasing the tension arm or the auxiliary tension arm in the rotational direction thereof, and a mechanism for changing the air pressure of the air cylinder may be provided as a tension adjusting mechanism.

It is obvious that the present invention is not limited to the above-mentioned embodiments and various modifications can be made within the scope of the technical idea.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a wire cut electric discharge machine showing an embodiment of the present invention.

[Explanation of symbols]

1 Wire cut electric discharge machine 2 wires 4 winding drum 6 controller 10 Feeding tension device 11 Feeding pulley 16 tension arm 17 Potentiometer 19 spring 30 Servo tension device 31 Pull-out pulley 36 Tension arm 37 Potentiometer 39 spring

Claims (3)

[Claims] 1. A wire-cut electric discharge machine for performing electric discharge machining on a work while traveling a wire to which tension is applied, an upstream side feed mechanism for feeding the wire to the work, and a downstream side feed mechanism for feeding the wire from the work. And a tension arm that applies a tension to the wire that turns around the fulcrum toward the workpiece, an urging mechanism that urges the tension arm in the direction of rotation, and detects the rotation angle of the tension arm. A wire-cut electric discharge machine comprising: a detection unit; and a control unit that feedback-controls a wire feed speed by the upstream feed mechanism so that the rotation angle of the tension arm approaches a target value. 2. A feeding mechanism for feeding the wire, an auxiliary tension arm for applying a tension to the wire which is rotated around a fulcrum toward the upstream side feeding mechanism, and the auxiliary tension arm is attached in the rotation direction. An urging mechanism for urging, a detection means for detecting the rotation angle of the auxiliary tension arm, and a control means for feedback-controlling the wire feeding speed of the wire feeding mechanism so that the rotation angle of the auxiliary tension arm approaches a target value. The wire-cut electric discharge machine according to claim 1, further comprising: 3. The wire cut electric discharge machine according to claim 1, further comprising a bobbin for winding the wire as the downstream side feed mechanism.