JPH11156551A - Arc adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively adjust an arc shape such as the length and diameter of the arc resulting in the improvement of the processing quality by installing a light receiving device, which observes the arc between a plasma torch and a material to be cut and outputs light receiving signals corresponding to an arc existing range. SOLUTION: A light receiving device 11 observes an arc 14 between a plasma torch 1 and a material 3 to be cut from the approximately vertical side, and outputs light receiving signals corresponding to the existing range of the arc 14. A control mechanism 12 is equipped with a function to judge whether the cutting phenomenon is good or not by comparing the arc 14 shape observed by the device 11 with the preset reference dimension. When the arc 14 shape is out of the range of the reference dimension, the control mechanism judges that a good cutting is not obtained and outputs the judged results to a warning device and the like. Further, the arc 14 can be adjusted by making a command to a moving mechanism 15, the power source of the arc 14 and the like from the control mechanism 12 in correspondence to the measured arc 14 shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc adjusting device for adjusting an arc of a plasma torch.

[0002]

2. Description of the Related Art In the cutting of a material to be cut using a plasma torch, the cutting quality depends on the arc shape during the cutting operation. The arc shape is an arc length, a diameter, a bend, or the like, and the cutting quality can be ensured by maintaining the arc shape within an appropriate range during the cutting operation. Generally, air sensors and arc sensors are frequently used as height sensors used for plasma cutting. The arc sensor can accurately measure the distance between the workpiece and the workpiece because there is no offset between the sensor and the plasma torch.However, when changing from vertical cutting to groove cutting during cutting, the arc voltage changes and measurement cannot be performed correctly. Generally used only for vertical cutting. On the other hand, the air sensor can perform measurement regardless of vertical cutting or groove cutting (the sensor position does not change even if the plasma torch is tilted), but there is some dissatisfaction with the measurement accuracy due to the offset from the plasma torch. That is, the distance between the sensor and the material to be cut can be measured correctly, but a deviation occurs because the distance between the plasma torch and the material to be cut is offset.

FIG. 5 shows an example of an air sensor. In FIG. 5, the air sensor is arranged such that a sensor nozzle 2 attached to a plasma torch 1 is opposed to a horizontally positioned workpiece 3 (steel plate) so as to be separated from the workpiece 3 (steel plate) upward, and air is provided between the sensor nozzle 2 and the workpiece 3. Detect back pressure. The sensor nozzle 2 is connected to a moving mechanism (not shown) that moves the plasma torch 1 up and down, and the moving mechanism is driven in response to a change in the exhaust pressure detection signal of the sensor nozzle 2, thereby causing the plasma torch 1 to cut the workpiece. Move to 3 However, the material to be cut 3 is not always flat, and when the material to be cut 3 is curved as shown in the figure, a displacement occurs due to the offset.

Therefore, as a height sensor of a plasma torch, an arc sensor and an air sensor are used in combination, and an arc sensor is used at the time of vertical cutting, and an air sensor is used at the time of cutting a groove.

[0005]

When an arc sensor and an air sensor are used together, there are problems such as an increase in size of the apparatus and an increase in cost. Further, installing a plurality of sensors in the vicinity of the plasma torch is a hindrance when cutting a material having a complicated shape, and also causes a problem that the cutting efficiency is reduced. In addition, the shape of the arc other than the arc length, such as the bend and diameter, has traditionally relied on visual adjustment by the operator.However, the arc shape is observed from a position away from the plasma torch through a filter or the like. Was not well understood, and there was a complaint that sufficient accuracy could not be obtained.

[0006] The present invention has been made in view of the above-mentioned problems, and has as its object to provide an arc adjusting apparatus which can obtain the following effects. (1) An arc shape such as an arc length and an arc diameter can be efficiently adjusted, and high processing quality can be obtained. (2) With the configuration in which the arc length is measured by the measuring means based on the light receiving signal from the light receiver, there is no offset, and even when the groove is cut, the distance of the plasma torch from the workpiece is accurately measured. can do. (3) The arc length measured by the measuring means is compared with the arc length stored in the storage means by the comparing means, and the movement of the plasma torch is controlled based on the difference between the two arc lengths, so that the plasma torch is covered. It can be located at a desired distance from the cutting material. (4) By making it possible to measure the arc length of the inclined arc, the plasma torch can be accurately positioned at a target distance from the material to be cut, regardless of the type of cutting, such as groove cutting. (5) By adjusting the arc based on the result of comparing the arc shape with the reference dimension, high cutting quality can be easily secured. (6) According to (1), the distance of the plasma torch from the material to be cut can be accurately measured by one unit, and cost reduction and size reduction can be achieved.

[0007]

According to the present invention, there is provided a photodetector for observing an arc between a plasma torch and a material to be cut and outputting a light reception signal corresponding to a range in which the arc exists. An arc adjusting device provided with the present invention is a means for solving the above-mentioned problem. CCD (Ch
(Arge Coupled Device) A camera or the like is adopted. The light receiver outputs a light reception signal corresponding to the arc existence region or the outline of the existence region. The received light signal is sent to a monitor to display an arc shape, and sent to a control mechanism to control a plasma torch or an arc voltage. The installation position of this receiver with respect to the arc may be the side perpendicular to the arc,
It is coaxial with the arc. Not only one light receiver but also, for example, a plurality of light receivers can be installed at different locations. Thereby, the arc shape can be grasped more accurately. The arc shape, arc length, arc bending,
This is the diameter of the arc. The adjustment of the arc is performed by manual adjustment by an operator based on a light reception signal or automatic adjustment by a control mechanism.

According to the present invention, there is provided a control mechanism for outputting a command based on the light receiving signal, the control mechanism comprising a central processing unit, and a measuring means for measuring an arc length based on the light receiving signal from the light receiver. Storage means for storing a reference value of the arc length, comparison means for comparing the reference value stored in the storage means with the value measured by the measurement means, and calculating the difference between the two arc lengths, It is also possible to adopt a configuration including output means for outputting a command signal to the moving mechanism for moving the torch based on the difference in the arc length calculated by the comparing means. According to this configuration, a height sensor of the plasma torch is configured, and the distance of the plasma torch from the workpiece is automatically adjusted based on the arc length measured by the measuring unit. Preferably, the storage means stores a plurality of types of reference values corresponding to, for example, types of cutting such as groove cutting. Thus, by comparing the reference value selected according to the type of cutting and the value measured by the measuring unit with the comparing unit, control for positioning the plasma torch at an appropriate position according to the type of cutting and the like is performed. realizable. In addition, in the storage means,
It is more preferable to provide a writing means for rewriting the reference value as needed. Thereby, the reference value is optimized as the cutting operation is accumulated, and the quality of the cut product is improved.

Further, according to the present invention, a vertical length measuring means for measuring an arc length in a direction perpendicular to a material to be cut, a parallel dimension measuring means for measuring an arc size in a direction along a surface of the material to be cut, and It is more preferable to employ a configuration in which the measuring means includes a slope length calculating means for calculating a parallel root of a sum of squares of the measured value of the vertical length measuring means and the measured value of the parallel dimension measuring side means. When the arc is perpendicular to the material to be cut, the arc length is measured by operating only the vertical length measuring means, and when the arc is inclined with respect to the material to be cut, the vertical length measuring means, the parallel dimension measuring means Then, the inclination length calculating means is operated to calculate the length of the arc in the axial direction. The storage means stores the reference values of the arc length both when the arc is perpendicular to the workpiece and when the arc is inclined.
Thereby, a more optimized arc length is obtained.

Further, in the present invention, it is possible to employ a configuration having a determination means for determining the quality of the cutting phenomenon based on the arc shape observed by the light receiving device. The determination of good or bad performed by the control mechanism is performed by comparing the bending or diameter of the arc observed by the light receiver with the reference dimension.
The reference size is a size range of the arc shape in which a good cutting phenomenon is obtained, and it is determined that a good cutting phenomenon is obtained if the arc shape observed by the light receiver is within the size range of the reference size, When it is out of the range of the reference size, it is determined that a good cutting phenomenon is not obtained. The judgment result is output to the moving mechanism by an electric signal or the like, and the arc is adjusted. The determination result is also used for controlling the arc voltage of the arc power supply. This makes it possible to efficiently obtain an arc shape that provides good cutting quality.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an arc adjusting device according to the present invention will be described below with reference to FIGS. In addition,
The same components as those in FIG. 5 are denoted by the same reference numerals, and description thereof will be simplified. Reference numeral 10 in FIG. 1 denotes an arc adjusting device (a height sensor for a plasma torch) of the present embodiment. As shown in FIG. 1, the arc adjusting device 10 includes a light receiving device (CCD camera) 11, a control mechanism 12 (controller), and a monitoring monitor 13, which are electrically connected to each other. .

The photodetector 11 is disposed apart from the plasma torch 1 and observes an arc 14 (plasma arc) between the plasma torch 1 and the workpiece 3 from a side substantially perpendicular to the arc 14. Then, a light receiving signal corresponding to the area where the arc 14 exists is output. Since the photodetector 11 incorporates a telephoto lens, there is no problem in receiving the light emitted from the arc 14 even if the distance from the plasma torch 1 is sufficiently ensured. Further, the light receiver 11 is moved while always maintaining a constant distance from the plasma torch 1 by supporting means (not shown). Therefore, the length of the arc 14 observed by the light receiver 11 is always proportional to the actual length of the arc 14 with a constant constant. Arc 14 length is usually 4mm
However, a sufficient separation distance is secured between the plasma torch 1 and the light receiver 11, so that an arc length of about 0 mm to 10 mm can be measured.

The control mechanism 12 is electrically connected to a movement mechanism 15 for moving (elevating) the plasma torch 1 with respect to the workpiece 3 in addition to the light receiver 11.
Command signal corresponding to the received light signal received from the moving mechanism 1
5 is output. The control mechanism 12 outputs a signal to the monitoring monitor 13 based on the light receiving signal, and
The image of the arc 14 observed in step 1 is displayed. This image displays only light having a certain intensity or more by removing useless light by an optical filter mounted on the light receiver 11 or a processing means interposed on an electric signal transmission circuit. Therefore, on the monitoring monitor 13, only a portion that effectively acts on the cutting of the arc 14 is displayed as shown in, for example, FIGS. 2 and 3.

Hereinafter, the configuration of the control mechanism 12 will be described with reference to FIG. The control mechanism 12 includes a central processing unit 12a
(CPU), measuring means 16 for measuring the length of arc 14 based on a light receiving signal from light receiver 11, storage means 17 for storing a reference value of arc 14 length, and reference value stored in storage means 17 Comparing means 18 for comparing the measured value with the measuring means 16 and calculating the difference between the two arc lengths.
Output means 19 for outputting a command signal to the moving mechanism 15 based on the difference between the arc lengths calculated by the comparing means 18
And electrically connected to each other.

The measuring means 17 includes a vertical length measuring means 20 for measuring the length of the arc 14 in the direction perpendicular to the material 3 to be cut, and a parallel dimension measuring means for measuring the size of the arc 14 along the surface of the material 3 to be cut. 21 and a slope length calculating means 22 for calculating a parallel root of the sum of the square of the measured value of the vertical length measuring means 20 and the measured value of the parallel dimension measuring side means 21.

In this measuring means 17, the vertical length measuring means 2
When the ratio of the measured value of the parallel dimension measuring means 21 to the measured value of 0 does not exceed a preset critical value, the arc 14
Since it is determined that the length is perpendicular to the workpiece 3, the non-use of the parallel dimension measuring means 21 is automatically selected. That is, as shown in FIG. 2, when measuring the length of the arc 14 perpendicular to the material 3 to be cut, the vertical length measuring means 20 measures the length of the arc 14 、 L, and the measured value is measured by the measuring means 17. Is output to the comparing means 18 as the measured value of Here, since the parallel dimension measuring means 21 is not used, no measurement value is calculated from the inclination length calculating means 22.

Conversely, when the ratio of the measured value of the parallel dimension measuring means 21 to the measured value of the vertical length measuring means 20 exceeds a predetermined critical value, the length of the arc 14 is inclined with respect to the workpiece 3. Is determined, the use of the parallel dimension measuring means 21 is automatically selected. At this time, as shown in FIG. 3, the vertical length measuring means 20 measures the length of the arc 14 in the vertical direction, and the parallel dimension measuring means 21 measures the arc 14 in the direction parallel to the workpiece 3 (horizontal direction). The length of the arc 14 is calculated by measuring the dimensions and further calculating the parallel root of the sum of the squares of the measured values of the vertical length measuring means 20 and the parallel dimension measuring side means 21 by the inclination length calculating means 22, The value is output to the comparing means 18 as a value measured by the measuring means 16.

In the storage means 17, when the arc 14 is vertical,
An appropriate reference value of the arc 14 length is stored in advance for each of the inclinations. In addition, the storage unit 17 also stores appropriate reference values for the length of the arc 14 in various cutting operations such as when cutting a groove, for each of the vertical and inclined arcs 14.

The comparison means 18 reads from the storage means 17 reference values corresponding to the type of cutting operation and the vertical and inclination of the arc 14 and compares them with the measurement values output from the measurement means 16. Here, when there is a difference between the measured value and the reference value that exceeds a preset allowable range, a command signal is output from the output unit 19 to the moving mechanism 15 to output the plasma torch 1.
Is moved to eliminate the difference. The output means 19 has a built-in output equivalent circuit, and the movement of the plasma torch 1 is repeatedly performed until the difference between the measured value and the reference value is eliminated. Thus, the plasma torch 1 can be positioned at an appropriate distance from the workpiece 3 set to the reference value.

Further, the control mechanism 12 has a function of comparing the shape of the arc 14 observed by the light receiver 11 with a preset reference dimension to determine the quality of the cutting phenomenon. ing. Here, arc 1
The four shapes include, besides the length of the arc 14, the bending of the arc 14, the diameter (width), and the like. The cutting quality of the arc 14 is affected not only by the length of the arc 14 but also by the shape of the arc 14. The control mechanism 12 measures the bending and the diameter of the arc 14 from the distribution range and the width of the arc 14. Then, the comparison unit 18 compares the reference dimension of the arc set in the storage unit 17 (eg, the size range of the arc shape with which a good cutting phenomenon can be obtained) with the shape of the arc 14 observed by the light receiver 11. Arc 14 observed by light receiver 11
If the shape is within the range of the reference size, it is determined that a good cutting phenomenon has been obtained, and if it is out of the range of the reference size, it is determined that a good cutting phenomenon has not been obtained. The judgment result is output to an alarm or the like by an electric signal or the like. It is also possible to adjust the arc 14 by outputting a command from the control mechanism 12 to the moving mechanism 15 or the power supply of the arc 14 in accordance with the measured shape of the arc 14. Thereby, the arc 14 of the target shape is obtained, and high cutting quality can be secured.

According to the arc adjusting apparatus 10, the distance of the plasma torch 1 from the workpiece 3 is measured by measuring the length of the arc 14 by the measuring means 16 based on the received light signal from the light receiver 11. In addition, since there is no offset, and unlike the arc sensor, even if the groove cutting is performed, the measurement of the length of the arc 14 is not affected, so that the positioning performance of the plasma torch 1 can be improved and the cutting quality can be improved.

The position of the plasma torch 1 is adjusted by observing the arc 14 light with the light receiver 11. Since the positional relationship between the light receiver 11 and the workpiece 3 is irrelevant, the installation position can be freely determined. Although it is necessary to restrict the moving range of the plasma torch 1 because the air sensor and the arc sensor are required to be positioned on the material 3 to be cut, it is necessary to restrict the moving range of the plasma torch 1. Do not give. Moreover, the length of the arc 14 inclined with respect to the workpiece 3 can be accurately and easily measured by the vertical length measuring means 20, the parallel dimension measuring means 21, and the inclination length calculating means 22. High cutting quality can be reliably obtained even when cutting is performed with the plasma torch 1 inclined.

The present invention is not limited to this embodiment. For example, an operation panel for inputting a command to the control mechanism 12 is connected, or a reference value is updated and optimized according to a work history. A configuration in which various writing means are connected to the control mechanism 12 can be adopted.

[0024]

As described above, according to the arc adjusting apparatus of the present invention, a photodetector for observing an arc between a plasma torch and a material to be cut and outputting a light reception signal corresponding to an existing range of the arc. And it is easy to grasp the arc shape such as the arc length and the arc diameter, so that the arc shape can be adjusted efficiently, and an excellent effect of stably obtaining high cutting quality can be obtained.

According to the second aspect of the present invention, the measured value of the arc length measured by the measuring means based on the light receiving signal from the light receiving device and the reference value previously stored in the storing means are compared by the comparing means. In comparison, when there is a difference between the two arc lengths exceeding an allowable range, a command signal is output from the output means to the moving mechanism for moving the plasma torch to move the plasma torch to adjust the distance to the workpiece. Thus, the following excellent effects can be obtained by eliminating the difference in the arc length in the comparison means. (A) Since the position of the plasma torch is controlled based on the measured value of the arc length, the positioning performance of the plasma torch can be improved, and the cutting quality can be improved. (B) Since there is no offset similarly to the arc sensor, the distance of the plasma torch from the workpiece can be accurately controlled. (C) A configuration in which the distance of the plasma torch from the material to be cut is measured by observing the arc light with a light receiver, and the distance from the material to be cut by the plasma torch regardless of the type of cutting such as groove cutting. The distance can be controlled accurately. (D) The distance of the plasma torch from the material to be cut can be accurately measured by one unit, and the cost and size can be reduced as compared with a case where an arc sensor and an air sensor are used in combination.

A vertical length measuring means for measuring an arc length in a direction perpendicular to the material to be cut; a parallel dimension measuring means for measuring an arc size in a direction along the surface of the material to be cut; And a slope length calculating means for calculating a parallel root of a sum of squares of the measured value of the parallel dimension and the measured value of the parallel dimension measuring side means. Can be measured accurately and easily, so that even when cutting is performed by inclining the plasma torch such as a groove cutting, an excellent effect that a high cutting quality can be reliably obtained is achieved.

According to a fourth aspect of the present invention, when a structure including a judging means for judging the quality of a cutting phenomenon based on an arc shape observed by a light receiver is adopted, the arc other than the arc length, such as the bending of the arc or the diameter, is used. The arc can be adjusted also from the shape, and an excellent effect that a higher cutting quality can be obtained stably is achieved.

[Brief description of the drawings]

FIG. 1 is an overall view showing an embodiment of an arc adjusting device of the present invention.

FIG. 2 is a view showing an arc displayed on a monitoring monitor of the arc adjusting device of FIG. 1, and showing an arc perpendicular to a workpiece.

FIG. 3 is a view showing an arc displayed on a monitoring monitor of the arc adjusting device of FIG. 1, and showing an arc inclined with respect to a material to be cut;

FIG. 4 is a block diagram showing a configuration of a control mechanism of the arc adjusting device of FIG. 1;

FIG. 5 is a diagram showing a conventional arc adjusting device,
It is a front view which shows an air sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Plasma torch, 3 ... Material to be cut (steel plate), 10 ... Arc adjusting device (Height sensor for plasma torch), 11
... Photodetector (CCD), 12... Control mechanism, determination means (controller), 12 a.
4 ... arc (plasma arc), 15 ... moving mechanism, 16
... Measurement means, 17 ... Storage means, 18 ... Comparison means, 19 ...
Output means, 20: vertical length measuring means, 21: parallel dimension measuring means, 22: inclination length calculating means.

Claims (4)

[Claims] 1. A plasma torch (1) and a workpiece (3)
An arc adjusting device (10), comprising: a light receiver (11) for observing an arc (14) between the two and outputting a light reception signal corresponding to a range in which the arc exists. 2. A control mechanism (12) for outputting a command based on the light receiving signal, wherein the control mechanism measures a central processing unit (12a) and an arc length based on a light receiving signal from the light receiving device. Measuring means (16), storage means (17) for storing a reference value of the arc length, comparing the reference value stored in the storage means with the value measured by the measuring means, and determining the arc length of both. Comparing means (18) for calculating a difference, and output means (19) for outputting a command signal to a moving mechanism (15) for moving the plasma torch based on the difference in arc length calculated by the comparing means. The arc adjusting device according to claim 1, wherein: 3. A vertical length measuring means for measuring an arc length in a direction perpendicular to a material to be cut, and a parallel dimension measuring means for measuring an arc size in a direction along a surface of the material to be cut. (21) and a slope length calculating means (22) for calculating a parallel root of a sum of squares of the measured value of the vertical length measuring means and the measured value of the parallel dimension measuring side means. Item 3. An arc adjusting device according to Item 2. 4. The arc adjusting apparatus according to claim 1, further comprising a determination unit configured to determine whether the cutting phenomenon is good or not based on an arc shape observed by the light receiver.