JPH09103879A - Shaft copying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft copying device which prevents collision between an electrode and a work and which improves the finish of the work. SOLUTION: The shaft copying device 1 for machining a work W is provided with a voltage detecting device 21 for detecting an arc voltage outputted from an electrode 13 to the work W and gap control device 25 which controls the gap, with the voltage signal inputted that is detected by this voltage detecting device 21. The device 1 is further provided with a monitoring device 27, which takes in the actual voltage at the time of travelling of either the machining head 15 or the work W by a first driving means 9 and which compares and judges between this actual voltage and a preset threshold value, and with a switching means 29 which turns off a second driving signal from the gap control device 25 when the actual voltage exceeds the upper/lower value of the threshold value in this monitoring device 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls a gap between an electrode and a work to be processed by changing a voltage output from an electrode provided on a processing head in a plasma processing machine or a welding machine. The present invention relates to an axis copying processing device.

[0002]

2. Description of the Related Art Conventionally, in a plasma processing machine, a welding machine or the like as an axis copying processing apparatus, a change in arc voltage output from an electrode provided on a processing head is input to an axis control section of an NC apparatus, and this axis is controlled. The gap between the electrode and the work is controlled to be always constant by feeding back from the control unit to the axis that moves the machining head up and down.

For example, the conventional axis copying apparatus 101 is
As shown in FIG. 5, a work table 103 on which a work W to be machined is placed is provided, and above the work table 103, the X-axis movable in the left-right direction (X-axis direction) in FIG. A carriage 105 is provided. A ball screw 107 extending in the X-axis direction is screwed into the X-axis carriage 105.
An X-axis drive motor 109 such as a servo motor is connected to one end, for example, the right end of 07.

On the X-axis carriage 105, a Z-axis carriage 111 is provided which is movable in the vertical direction (Z-axis direction). A processing head 115 having an electrode 113 is mounted below the Z-axis carriage 111. A ball screw 117 extending in the Z-axis direction is screwed into the Z-axis carriage 111, and a Z-axis drive motor 119 such as a servo motor is connected to the upper end of the ball screw 117.

With the above configuration, the work W is placed on the work table 103, and the X-axis drive motor 109
The X-axis carriage 105 is moved in the X-axis direction by driving and rotating the ball screw 107.
Further, by driving the Z-axis drive motor 119 and rotating the ball screw 117, the Z-axis carriage 11
1 will be moved in the Z-axis direction.

A voltage detection device 121 is connected to the electrode 113 and the work W, and the voltage detection device 1 is also provided.
21 is connected to the NC device 123. Moreover, this N
The C device 123 is connected to the X-axis drive motor 109 and the Z-axis drive motor 119.

With the above construction, the X-axis carriage 105 can be moved in the X-axis direction and the Z-axis carriage 111 can be moved in the Z-axis direction, and at the same time, the arc output from the electrode 113 can be used to perform plasma processing or welding on the work W. Done.

At this time, a change in the arc voltage output from the electrode 113 is detected by the voltage detecting device 121, and the detected voltage signal is taken in by the NC device 123, and the NC device 1
Machining is performed by feeding back a motor drive signal from 23 to the Z-axis drive motor 119 and controlling the gap G between the electrode 113 and the work W to be always constant.

This control is important for finishing such as cutting the warped work W. Moreover, this control, as shown in FIG.
This is because the relationship with and is in a proportional relationship.

[0010]

By the way, in the above-described conventional axis copying apparatus 101, the X-axis drive motor 1 is used.
When 09 is driven, the ball screw 107 is rotated and the X-axis carriage 105 is moved in the X-axis direction in FIG. 5, so that the electrode 113 also moves in the same direction.

When the electrode 113 moves in the X-axis direction,
As shown in FIG. 7, the voltage also changes at the left and right speeds. This means that when the left and right speeds change, the gap G is considered to change and the electrode 113 is controlled in the vertical direction. That is, it is not known whether the voltage change is due to the gap G or the speed.

Further, when the machining head 115 is moving in the left-right direction, for example, as shown in FIG. 8, in a place without the work W, that is, a hole or a cross point,
Since the gap G becomes large, the voltage also largely changes as shown in FIG.

That is, since the voltage changes greatly at a position where the speed changes due to a corner or the like, or where there is no work W, that is, a hole or a cross point, the electrode 113 collides with the work W. Even if it does not collide, there is a problem that the finish such as cutting becomes poor.

An object of the present invention is to provide an axial copying apparatus which prevents the electrode from colliding with the work and improves the finish of the work.

[0015]

In order to achieve the above-mentioned object, according to a first aspect of the present invention, there is provided an axial contour machining apparatus in which a machining head having an electrode and a workpiece to be machined are relatively first.
An axial copying machining apparatus for performing machining on a workpiece by moving the machining head in the vertical direction by a second driving means while moving the machining head by driving means and constantly controlling the gap between the electrode and the workpiece. A voltage detection device for detecting an arc voltage output from the electrode to the work, a gap control device for inputting a voltage signal detected by the voltage detection device to control the gap, and a machining head or a work by the first driving means. Of the actual voltage at the time of either one of the movements, and a monitoring device for comparing and judging the actual voltage with a preset threshold value, and with this monitoring device, the actual voltage is above or below the threshold value. Switching means for turning off the second drive signal from the gap control device when the value exceeds the value. And it is characterized in Rukoto.

Therefore, when machining a work,
The threshold value set in advance is input to the monitoring device.
Then, for example, the actual voltage of the arc when the workpiece is fixed and the machining head is moved in the left-right direction is detected by the voltage detection device, and the detected actual voltage is taken into the gap control device, and the monitoring device is also provided. To take in.

When it is determined that the actual voltage detected by the monitoring device is within the preset upper and lower threshold values, the switch of the switching means is turned on to move the gap control device to the second driving means. A drive signal is applied to control the second drive means to control the gap between the electrode and the work to be constant.

When it is determined that the actual voltage detected by the monitoring device exceeds the preset upper and lower threshold values, the switch of the switching means is turned off to drive the gap control device to the second driving means. Since the second driving means is controlled without giving a signal, it is possible to prevent the electrode from colliding with the work and improve the finish of the work.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, an axial copying apparatus 1 such as a plasma processing machine or a welding machine is a work W to be processed.
Is provided with a work table 3 on which the work table 3 is placed, and above the work table 3 in the left-right direction (X-axis direction) in FIG.
A movable X-axis carriage 5 is provided. The X-axis carriage 5 has a ball screw 7 extending in the X-axis direction.
An X-axis drive motor 9 such as a servo motor as a first drive means is connected to one end, for example, the right end of the ball screw 7. The X-axis drive motor 9 is provided with an encoder E ₁ for detecting the amount of movement.

With the above structure, when the X-axis drive motor 9 is driven, the ball screw 7 is rotated and the X-axis carriage 5 is moved in the X-axis direction.

On the X-axis carriage 5, the vertical direction (Z
A Z-axis carriage 11 that is movable in the axial direction) is provided. A processing head 15 having an electrode 13 is mounted below the Z-axis carriage 11. A ball screw 17 extending in the Z-axis direction is screwed into the Z-axis carriage 11, and a Z-axis drive motor 19 such as a servo motor as a second drive means is connected to the upper end of the ball screw 17. There is. The Z-axis drive motor 19 is equipped with an encoder E ₂ for detecting the amount of movement.

With the above structure, when the Z-axis drive motor 19 is driven, the ball screw 17 is rotated and the Z-axis carriage 11 is moved in the Z-axis direction.
The electrode 13 provided in the same is also moved in the same direction.

A voltage detecting device 21 is connected to the electrode 13 and the work W, and the voltage detecting device 21 is N
It is connected to the C device 23. Moreover, this NC device 23
Is connected to the X-axis drive motor 9 and the Z-axis drive motor 19.

With the above structure, the X-axis carriage 5 is moved in the X-axis direction and the Z-axis carriage 11 is moved in the Z-axis direction, and the workpiece W is processed by the arc output from the electrode 13 such as plasma processing or welding processing. Will be done.

The NC device 23 has an electrode 13 and a work W.
There is provided a gap control device 25 for controlling the gap G between the and, a monitoring device 27 for monitoring a change in voltage when the X-axis carriage 5 moves in the X-axis direction, and a switching means 29.

The gap control 25 takes in the voltage signal detected by the voltage detection device 21 and outputs a normal up / down drive signal to the Z-axis drive motor 19 so that the gap G is always constant. The drive signal is added with the drive signal.

In the monitoring device 27, as shown in FIG. 2, the reference voltage A of the voltage waveform immediately after piercing is taken in, and the upper and lower limit values B and C as shown in FIG. Is set and stored in advance. Therefore, in the monitoring device 27, the upper limit threshold value E
After (= A + B) and the lower limit threshold F (= A−C) are calculated, the actual voltage D and the upper and lower limit thresholds E and F are compared and determined.

The operation of controlling the gap G between the electrode 13 and the work W with the above structure will be described with reference to the flow chart shown in FIG. 4. In step S1, the reference voltage A immediately after piercing is detected by the voltage detecting device. It is detected at 21 and input to the monitoring device 27 to be temporarily stored. In step S2, the upper and lower threshold values B and C set in advance are input to the monitoring device 27 and stored therein.

In step S3, the voltage D at the time of processing, for example, at the time of cutting is detected by the voltage detection device 21 and taken into the monitoring device 27. In step S4, the upper and lower limit voltages E and F are set to E = A
Calculation processing is performed with + B and F = A-C.

In step S5, the actual voltage D and the upper limit voltage E
And D is not D> E (D <E), the process proceeds to step S6, and in step S6, the actual voltage D and the lower limit voltage F are compared and determined. If not D <F (D> F), the process proceeds to step S7, the switch of the switching means 29 is turned on, the drive signal from the gap control 25 is added to the normal upper and lower drive signals, and the Z-axis drive motor. 9 is controlled to control the gap G between the work W and the electrode 13 to be constant, so that the work W can be processed.

When D> E in step S5 and D <F in step S6, step S6
8, the switch of the switching means 29 is turned off and the Z-axis drive motor 9 is controlled by the normal up and down drive signals.

Thus, for example, when the speed at which the machining head 15 equipped with the electrode 13 moves in the left-right direction is changing, or where there is no work W such as holes or cross points, even if the voltage changes greatly. Can be ignored. Therefore, the collision between the electrode 13 and the work W at the corner or the hole of the work W, the cross point,
It is possible to prevent a misfire of the arc and improve the finish of the work W.

The present invention is not limited to the above-described embodiment, but can be embodied in other modes by making appropriate changes. Although the work W is fixed and the X-axis carriage 5 is moved in the X-axis direction in the example of the present embodiment, the X-axis carriage 5 is described.
May be fixed so that the work W can be moved in the X-axis direction. Further, the work W or the work head 15 may be fixed, and the work head 15 or the work W may be moved in two dimensions (X, Y axis directions) or three dimensions (X, Y, Z axis directions). is there.

Not only the change in the arc voltage of its own is used, but a contact or non-contact sensor for copying may be used exclusively. Further, the monitoring device 27 may be provided outside the NC device 23.

The signal from the voltage detection device 21 may detect a current instead of a voltage, and may be either analog or digital.

[0037]

As can be understood from the examples of the embodiment as described above, according to the invention of claim 1, when a workpiece is machined, a preset threshold value is input to the monitoring device. Keep it. Then, for example, the actual voltage of the arc when the workpiece is fixed and the machining head is moved in the left-right direction is detected by the voltage detection device, and the detected actual voltage is taken into the gap control device, and the monitoring device is also provided. To take in.

When it is determined that the actual voltage detected by the monitoring device is within the preset upper and lower threshold values, the switch of the switching means is turned on to move the gap control device to the second driving means. By driving the second driving means, the gap between the electrode and the work is controlled to be constant.

When it is determined that the actual voltage detected by the monitoring device exceeds the preset upper and lower threshold values, the switch of the switching means is turned off and the gap control device is driven to the second driving means. Since the second driving means is controlled without giving a signal, it is possible to prevent the electrode from colliding with the work and improve the finish of the work.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an axial copying apparatus embodying the present invention.

FIG. 2 is an explanatory diagram of monitoring a processing voltage at the time of cutting by a monitoring device.

FIG. 3 is an explanatory diagram of monitoring a processing voltage at the time of cutting by a monitoring device.

FIG. 4 is a flowchart for controlling a gap between an electrode and a work according to the present invention.

FIG. 5 is a configuration diagram of a conventional axial copying apparatus.

FIG. 6 is a diagram showing a relationship between a gap between an electrode and a work and a voltage.

FIG. 7 is a diagram showing a relationship between a gap between an electrode and a work and a voltage.

FIG. 8 is an explanatory diagram when a cross point processing is performed on a work with a conventional electrode.

FIG. 9 is an explanatory diagram showing a voltage change when a work is subjected to cross-point machining with a conventional electrode.

[Explanation of symbols]

 1-axis copying processing device 5 X-axis carriage 9 X-axis drive motor (first drive means) 11 Z-axis carriage 15 processing head 19 Z-axis drive motor (second drive means) 21 voltage detection device 23 NC device 25 gap control device 27 Monitoring device 29 switching means

Claims (1)

[Claims] 1. A machining head provided with an electrode and a workpiece to be machined are relatively moved by a first driving means, and the machining head is vertically moved by a second driving means so as to move between the electrode and the workpiece. Is a shaft copying machining device for machining the work by controlling the gap to be always constant, the voltage detection device detecting an arc voltage output from the electrode to the work, and the voltage signal detected by the voltage detection device. A gap control device for inputting and controlling the gap, and an actual voltage when either the machining head or the work is moved by the first driving means are taken in, and the actual voltage is set as a preset threshold value. The monitoring device for comparing and judging, and the gap when the actual voltage exceeds a value above or below the threshold value in this monitoring device. And a switching means for turning off the second drive signal from the control device.