JPH08155644A - Arc welding monitoring device - Google Patents

Abstract

PURPOSE: To cope with different modes by one monitor so as to improve monitoring function, operatabilily and cost. CONSTITUTION: An average value operation part consists of a data extraction part 52 and average value operating part 54, a discrimination processing part consists of a comparing part 56 and discriminating part 58. The setting values of a travel pitch 5 and averaging time T which are used in the averaging processing part are given from an averaging time/travel pitch storing part 64. The setting value of upper limit/lower limit monitoring values UM, UL and a discrimination monitoring value N which are used in the discrimination processing part are given from a monitoring value storing part 66. A monitoring condition switching part 68 responds to the switching signal sent from a controller of arc welding machine, the monitoring condition, which is given from the averaging time/travel pitch storing part 64 and monitoring value storing part 66 to the averaging processing parts 52, 54 and the discrimination processing parts 54, 58, is switched to one of the starting NO set in the next sequence.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc welding monitor device for monitoring arc welding.

[0002]

2. Description of the Related Art In arc welding, when a voltage is applied between a welding electrode (arc welding rod) and a material to be welded (base metal), the tip of the welding electrode is heated by arc heat to form droplets and become a base metal surface. It is a welding method for fusion welding the materials to be welded by utilizing the phenomenon of transition to No. 2, and is widely used for processing automobiles, electric / electronic parts and the like.

In arc welding, the welding current and arc voltage reflect the welding condition or welding result. However, since the ionosphere (gas) called arc constitutes a part of the welding circuit, the welding current is too high to measure the instantaneous value. And the arc voltage fluctuates drastically. Therefore, a method is used in which the welding current and the arc voltage are averaged at regular intervals and the average value is used as the measured value.

The applicant of the present invention filed Japanese Patent Application No. 2-19891 of the prior application.
7 discloses an adaptive arc welding monitor device that performs averaging measurement by the moving average method. In the moving average method in this arc welding monitor, while moving the averaging time (average value calculation section) T on the time axis at a constant pitch δ (δ <T), each averaging time Ti is calculated for each moving pitch δ. It is a measuring method to find the average value of the welding current or arc voltage in. According to such a moving average method, meaningless noise and fluctuations such as undershoot and overshoot contained in the measurement target (welding current, arc voltage) or measurement data can be removed in a wide averaging time T. At the same time, it is possible to reliably capture substantial arc fluctuations with a narrow movement pitch δ.

[0005]

In the above-mentioned conventional arc welding monitor device, the monitoring conditions (averaging time, moving pitch) for averaging process and the monitoring conditions (upper and lower limit monitoring values) for determination process. It was possible to arbitrarily select each value (data) of, but only one set of monitoring condition data can be set at one time, and the value of the monitoring condition can be switched to another value during arc welding. There wasn't. For this reason, a problem occurs when the shape, plate thickness, number of laps, etc. of the welded portion changes during arc welding.

For example, two workpieces 100 and 102 each having a shape as shown in FIG.
When joining No. 4 by arc welding, the welding speed and welding current are usually increased in the straight section 104a and decreased in the arc or curved section 104b. FIG.
As shown in FIG. 7, even when the terminal fitting 108 is joined to the cylindrical conductor 106 of the electric component by arc welding, the straight section 110a and the curved section 110 of the welded portion are similarly formed as described above.
It is usual to change the welding speed and / or the welding current with b.

In such a case, the averaging time and the moving pitch are, for example, the straight section 104a (1) where the welding speed is fast.
08a), it is not necessary to make detailed measurements, so a relatively large value is used, and curve sections 104b, 10
In 8b, a relatively small value is set for fine measurement. Further, the comparison reference values (upper limit and lower limit monitoring values) for determination are also generally in the straight line section 104a where the welding current is large.
A relatively large value is suitable for (108a), and a relatively small value is suitable for the curved sections 104b and 108b where the welding current is small.

However, in the conventional arc welding monitor, the values of these monitoring conditions (averaging time, moving pitch, upper limit and lower limit monitor values, etc.) are fixed to one set value during one arc welding. Therefore, it has not been possible to cope with the changes in the welding mode or welding conditions (welding speed, welding current, etc.) as described above.

Therefore, conventionally, the section to be measured or monitored is narrowed down to one, for example, the curve section 10 in the above example.
4b, 108b, the values of the respective monitoring conditions are set for that section, and the curve section 104b,
Only 108 arc welds were monitored. Alternatively, two monitor devices are prepared, and the linear sections 104a and 108a and the curved sections 104b and 10 are provided respectively.
The monitoring condition data corresponding to 8b is set and input, and when the welding mode or the welding condition is switched during arc welding, the monitor device is switched in conjunction with it. However, the monitoring function is often useless if only a part of the section is monitored like the former,
However, it is inconvenient in terms of cost to use a plurality of devices like the latter.

Further, in the conventional arc welding monitor device,
The set value of each monitoring condition is erased when another set value is input.Therefore, when the operator wants to use the set value again later, the set value must be input again. In addition, there is a problem that setting value data management and input operation are troublesome.

The present invention has been made in view of the above problems, and provides an arc welding monitor device capable of coping with different welding modes with one unit, and having improved monitoring function, operability and cost efficiency. The purpose is to

[0012]

In order to achieve the above object, a first arc welding monitoring device of the present invention is an arc welding monitoring device for monitoring arc welding by an arc welding machine, wherein a welding electrode and a base material are provided. Detects the welding current flowing,
Welding current detection means for outputting a signal representing the current value of the welding current, and a first for averaging processing set in advance
A welding current average value calculating means for obtaining an average value of the welding current at constant time intervals from the value of the output signal of the welding current detecting means by using the monitoring condition data of No. Determining means for determining a welding status or a welding result from the average value of the welding current obtained by the welding current average value calculating means using the monitoring condition data of No. 1, and the first for each of the preset starting conditions. And monitoring condition setting means for setting second monitoring condition data, and the first condition for each starting condition set by the monitoring condition setting means.
And monitoring condition storage means for storing second monitoring condition data, and used by the welding current average value calculating means and the determining means in response to switching of welding conditions of arc welding executed by the arc welder. A monitoring condition switching means for switching the first and second monitoring condition data is provided.

A second arc welding monitoring device of the present invention is an arc welding monitoring device for monitoring arc welding by an arc welding machine, which detects an arc voltage between a welding electrode and a base metal, and a voltage value of the arc voltage. Arc voltage detecting means for outputting a signal indicating the arc voltage, and using the first monitoring condition data for averaging processing set in advance, the average of the arc voltage at constant time intervals from the output signal of the welding current detecting means. A welding condition is calculated from the average value of the arc voltage calculated by the welding current average value calculation means using the arc voltage average value calculation means for obtaining a value and the second monitoring condition data for preset determination processing. Or a determination means for determining a welding result, a monitoring condition setting means for setting the first and second monitoring condition data for each preset start condition, and the monitoring In response to the switching of the welding condition of the arc welding executed by the arc welding machine, the monitoring condition storing means for storing the first and second monitoring condition data for each starting condition set by the condition setting means, The arc voltage average value calculating means and the monitoring condition switching means for switching the first and second monitoring condition data respectively used in the determining means are provided.

[0014]

In the present invention, the monitoring condition setting means is
Different welding conditions are assigned to each welding mode of arc welding, and the first monitoring condition data for averaging processing and the second monitoring condition data for determination processing are set to desired values for each welding condition. The set value of is stored (held) in the monitoring condition storage means. Then, when the welding conditions change during arc welding, in response to a predetermined signal or the like from the arc welder side, the monitoring condition switching means switches the equipment start condition and the monitoring condition data to correspond to the new welding condition. The monitoring operation (averaging process, determination process) is continuously executed under the monitoring condition data.

[0015]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 shows the overall construction of an embodiment in which the arc welding monitor device of the present invention is applied to a DC arc welding machine. This DC arc welder applies a DC voltage between the welding electrode (welding wire) 14 and the base metal 16 on the welding torch 12 side of the power supply device 10 to perform MIG welding or MAG welding by the gas shield arc welding method. . Welding wire 1
4 and the base metal 16, an arc is generated in an atmosphere of a shielding gas composed of an inert gas or carbon dioxide gas, and the consumable welding wire 14 is melted and sent to the base metal 16 side at a predetermined speed. It is being paid.

In this arc welding machine, the arc welding monitor apparatus of this embodiment is provided with means for detecting the arc voltage and welding current as follows.

To detect the arc voltage, a pair of input terminals of an arc voltage detection circuit 18 are connected to the welding wire 14 and the base material 16, respectively. Arc voltage detection circuit 1
The output terminal of 8 is connected to the input terminal of the A / D converter 20, and the output terminal of the A / D converter 20 is connected to the data terminal of the CPU 24. During arc welding, an analog voltage signal VE representing the arc voltage E is obtained at the output terminal of the arc voltage detection circuit 18. The analog voltage signal E is converted into a digital signal by the A / D converter 20 with a predetermined quantization bit number (for example, 8 bits) and a predetermined sampling frequency (for example, 5000 Hz), and this digital signal is input to the CPU 24.

Further, in order to detect the welding current, a current detection coil 28 is attached to the conductor 26 connecting the power supply device 10 and the base material 16, and the output terminal of this coil 28 is the input terminal of the welding current detection circuit 30. Are connected. The output terminal of the welding current detection circuit 30 is connected to the input terminal of the A / D converter 32, and the output terminal of the A / D converter 32 is the CPU 24.
Connected to the data terminal of. During arc welding, an analog voltage signal VI representing the welding current I is obtained at the output terminal of the welding current detection circuit 30. The A / D converter 32 is
The analog voltage signal VI from the welding current detection circuit 30 is converted into a digital signal with a predetermined quantization bit number (for example, 8 bits) and a predetermined sampling frequency (for example, 5000 Hz), and this digital signal is given to the CPU 24.

The CPU 24 includes a keyboard 34 and a ROM 3
6, RAM 38, display device 40, printing device 42, external interface circuit 44, etc.
Various calculations and controls in this arc welding monitor device are performed according to the program stored in 36. RA
The data calculated by the CPU 24 is stored in the M38 as well as the monitoring condition data input through the keyboard 34. Display device 40 and printing device 42
Is used for outputting measured values, judgment results, and the like. The external interface circuit 44 is used for connection with a controller or the like of the arc welding machine.

FIG. 2 is a block diagram of functions related to the CPU 24 in this arc welding monitor device. Measurement data input unit 50, data extraction unit 52, average value calculation unit 5
4, the comparison unit 56 and the determination unit 58 each include the CPU 24.
(Arithmetic control unit), ROM 36 (program storage unit), and R
AM 38 (data storage unit). Output unit 60
Is a CPU 24, a ROM 36, a RAM 38, and a display device 4.
0 (determination result display output section) or the printing device 42 (determination result print output section). Monitoring condition setting unit 62
Is a keyboard 34 (setting data input section) and the CPU 24.
The ROM 36, the RAM 38, and the display device 40 (setting data display unit). Each of the averaging time / moving pitch storage unit 64 and the monitoring value storage unit 66 is composed of the CPU 24 and the RAM 38. The monitoring condition switching unit 68 includes the external interface circuit 44 (switching signal input unit) and the CPU.
24 and ROM 36.

The operation of the averaging process and the determining process in this arc welding monitor will be described with reference to the timing chart of FIG.

The measurement data input section 50 includes an A / D converter 2
From 0 or 32, a series of digital signals (measurement data) having digital values as shown in FIG. The data interval t is calculated by the A / D converter 20,
26 corresponds to the sampling frequency.

The data extraction section 52 is a measurement data input section 5
From the series of data taken in 0 ((A) in FIG. 3), as shown in (B0), (B1), (B2), (B3), ... Data included in the calculation period W0, W1, W2, W3, ... Of the time T is extracted.

The average value calculation unit 54 obtains moving average values M0, M1, M2, M3, ... For the data extracted by the data extraction unit 56 for each calculation period W0, W1, W2, W3 ,. (C) of 3).

The comparison unit 56 compares the moving average values M0, M1, M2, M3, ... Obtained by the average value calculation unit 54 with the upper limit monitoring value UM,
Compare with the lower limit monitoring value UL ((C) in FIG. 3).

The judging unit 58 receives the comparison result from the comparing unit 56, and when LM ≤Mi ≤UM, "appropriate", Mi
When <LM, it is judged as "unsuitable because it is below the lower limit", and when UM <Mi, it is judged as "unsuitable because it is above the upper limit" (see FIG. 3).
(D)). Further, the determination unit 58 collects all determination results for each process, for example, and outputs a "caution" determination result when the number of "unsuitable" exceeds the determination monitoring value N.

The determination result obtained by the determination unit 58 is sent to the output unit 60 and displayed on the LED display element or the lamp of the display device 40, or printed out by the printing device 42.

FIG. 4 shows an example of the operation of the moving average method in this arc welding monitor device. FIG. 4A is a waveform diagram of the welding current I and the arc voltage E before the moving average represented by the output signals of the current detection circuit 30 and the voltage detection circuit 18,
FIG. 4B is a waveform diagram of the welding current I and the arc voltage E after the moving average obtained from the calculation result of the moving average calculation unit 54. As is clear from these figures, by obtaining the moving average for the welding current I and the arc voltage E during arc welding, their fluctuations can be clearly clarified, and by extension, the situation or results of arc welding. Can be determined with high accuracy.

In the above moving average processing, the data extraction unit 52 sets the set values of the moving pitch δ and the averaging time T as monitoring conditions for extracting the data included in each calculation period W0, W1, W2, .... To use. In addition, the average value calculation unit 54
Is the moving average value M0, in each calculation period W0, W1, W2, ...
Averaging time T as a monitoring condition for obtaining M1, M2, ...
The setting value of is used. The set values of the moving pitch δ and the averaging time T are given from the averaging time / moving pitch storage unit 64.

Further, in the above judgment processing, the comparison unit 5
6 uses the set values of the upper limit and lower limit monitoring values UM, UL as monitoring conditions for evaluating each moving average value M0, M1, M2, ..., and the determining unit 58 determines whether the arc welding in one step is good or bad. The set value of the judgment monitoring value N is used as the monitoring condition of. The set values of the upper limit and lower limit monitoring values UM, UL and the judgment monitoring value N are given from the monitoring value storage unit 66.

In the monitoring condition setting unit 62, a setting value input routine on the device side and a key input operation on the operator side are performed, as shown in FIG.
In the format shown in, that is, for each of a plurality of (for example, up to 15) start-up NO. The value of (Ti, δi,
UMi, ULi, Ni) are set. Then, of the monitoring condition data set by the monitoring condition setting unit 62, the set values (Ti, δi) of the averaging time and the moving pitch are stored (held) in the averaging time / moving pitch storage unit 64, and the upper limit and Lower limit monitoring value and judgment monitoring value settings (UMi, U
Li, Ni) is stored (held) in the monitoring value storage unit 66.

In this embodiment, the monitoring condition setting unit 62 is also set to the switching order of the start NO.
The set value of the switching order is also stored in an appropriate storage area or register in the RAM 38.

In response to a switching signal sent from the controller of the arc welding machine, the monitoring condition switching unit 68 refers to the set value of the starting NO. Switching order, and the averaging time / moving pitch storage unit 64 and The averaging processing unit (52, 54) and the determination processing unit (54,
58) monitoring condition data (Ti, δi),
Start up (UMi, ULi, Ni) in the following order
No., such as (Ti + 2, δj + 2), (UMi + 2,
Ui + 2j, Ni + 2).

FIG. 6 shows the difference in the average value measurement data when the averaging time T is changed. 6A is a waveform diagram of the welding current I and the arc voltage E before the moving average represented by the output signals of the current detection circuit 30 and the voltage detection circuit 18, and FIG.
(B) and (C) are waveform diagrams of the welding current I and the arc voltage E after moving average obtained from the calculation result of the moving average calculation unit 54 when the moving pitch δ is 20 msec. However, the averaging time T in FIG. 6B is 100 msec, and the averaging time T in FIG. 6C is 1000 mse.
c.

As described above, even if the original waveforms of the welding current I and the arc voltage E are the same, if the averaging time T is changed, the value of the average value measurement data changes, and the monitoring result also differs. Therefore, the average value measurement data (that is, the monitoring condition data) may be selected or switched so as to best suit the aspect of arc welding, welding conditions, and the like.

As described above, in the arc welding monitor apparatus of this embodiment, the command (switching signal) from the arc welder side is provided.
In response to the above, the monitoring condition data can be switched in the order of preset start NO. Therefore, even if the shape of the welded part, the plate thickness, the number of overlaps, etc. change during arc welding in the arc welder and the welding conditions (welding speed, welding current, etc.) change accordingly, this arc welding monitor device It is possible to respond to that change.

For example, in the case of FIG. 7, different starting N is applied to the straight section 104a and the curved section 104b of the welded part.
O. For example, [1] and [4] are assigned, and the optimum monitoring condition data (T1, δ1,
UM1, UL1, N1), (T4, δ4, UM4, UL4, N4) are set, and the start NO. Order may be set as [1] → [4] → [1].

Then, while the welding point of the arc welding is in the straight line section 104a, the above-mentioned monitoring is performed by the monitoring condition data (T1, δ1, UM1, UL1, N1) of the start NO. [1]. When the welding point approaches from the straight line section 104a to the curved section 104b, the controller of the arc welding machine issues a switching signal, so that the arc welding monitor apparatus switches the starting NO. To [4]. This allows
Start while the welded point is in the curved section 104b NO. [4]
The above-mentioned monitoring is performed by the monitoring condition data (T4, δ4, UM4, UL4, N4). When the welded point passes through the curved section 104b, the controller of the arc welding machine again issues a switching signal, so that the present arc welding monitoring apparatus switches to startup NO. [1], and the monitoring condition data (T1, δ1 again). , UM1, UL1, N1) are used.

Also in the case of FIG. 8, each welding section 108a, 10a
The same operation as described above is performed by assigning different starting NOs. To 8b, setting the optimum monitoring condition data for each starting NO., And setting the order of starting NO. To match the welding section. In addition to this, for example, when it is desired to intensively measure and monitor a specific welding point in a series of welded parts in detail, depending on the mode of arc welding, the start NO. The setting contents of can also be arbitrarily changed.

In the arc welding monitoring apparatus according to the present embodiment, the value of the moving pitch δ is made to coincide with the value of the averaging time T, so that the averaging time T on the time axis can be changed. It is also possible to perform a measuring method that is repeated periodically to obtain an average value within each averaging time T (calculation period W).

As described above, in the arc welding monitoring apparatus of this embodiment, the welding conditions of the arc welding (welding speed, welding current, etc.) are generally associated with the welding operation of the arc welding machine.
The start-up conditions are switched in a predetermined order in conjunction with the switching, and each monitoring condition data is switched to one corresponding to the new welding condition after the switching. As a result, even if the shape, plate thickness, number of layers, etc. of the welded part changes during arc welding, this device can perform monitoring operation without interruption for the entire welding time Can be obtained.

Also, a number of starting conditions can be set,
Since the monitoring condition data set and input for each start condition are held in the memory (64, 66), it is sufficient to set and input each data once, and it is not necessary to repeat the same input operation.
The burden on the operator can be significantly reduced in terms of data management and operability.

In the above-mentioned embodiment, the order of starting NO. Is preset on the side of the arc welding monitor, and when the welding is carried out, the sequence is set in accordance with the switching signal from the controller of the arc welding machine. The start NO. Was switched to and the monitoring condition data was switched. However, without setting the order of start-up NO., The start-up NO. Is specified by the switching signal from the controller of the arc welding machine, and the start-up NO. And monitoring condition data are switched on the arc welding monitor side as specified. It is also possible to do so. In addition, the starting NO. In the above embodiment is an example of the starting condition, and it is possible to use symbols other than numbers or arbitrary information as the starting condition. Further, the types of monitoring condition data in the above embodiment are also examples, and it is possible to use arbitrary monitoring conditions according to the monitoring function.

Further, although the arc welding machine in the above-mentioned embodiment is one for performing MIG welding or MAG welding, the arc welding monitor device of the present invention can be applied to an arc welding machine for performing TIG welding.

[0046]

As described above, according to the arc welding monitor apparatus of the present invention, it is possible to continuously execute the monitoring operation by switching the monitoring condition data in response to the switching of the welding conditions in the arc welding. Thus, one unit can support different welding modes, and the monitoring function, operability, and cost efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment in which an arc welding monitor device of the present invention is applied to a DC arc welding machine.

FIG. 2 is a block diagram showing a configuration of functions related to a CPU in the arc welding monitor device in the embodiment.

FIG. 3 is a timing chart for explaining an operation of an averaging process and a determining process in the arc welding monitor device of the embodiment.

FIG. 4 is a waveform diagram showing an example of the operation of the moving average method in the arc welding monitoring apparatus of the embodiment.

FIG. 5 is a diagram showing a format of data stored in a monitoring condition data storage unit in the arc welding monitoring apparatus in the embodiment.

FIG. 6 is a waveform diagram showing a difference in average value measurement data when the averaging time is changed in the arc welding monitor device in the example.

FIG. 7 is a perspective view showing an example of a case where welding conditions for arc welding are switched.

FIG. 8 is a perspective view showing another example when the welding conditions of arc welding are switched.

[Explanation of symbols]

 14 welding wire (welding electrode) 16 base material 18 arc voltage detection circuit 24 CPU (microprocessor) 28 current detection coil 30 welding current detection circuit 34 keyboard 36 ROM 38 RAM 44 external interface circuit 52 data extraction unit 54 average value calculation unit 56 Comparison unit 58 Judgment unit 62 Monitoring condition setting unit 64 Averaging time / moving pitch storage unit 66 Monitoring value storage unit 68 Monitoring condition switching unit

Claims (5)

[Claims] 1. An arc welding monitoring device for monitoring arc welding by an arc welding machine, comprising: welding current detecting means for detecting a welding current flowing through a welding electrode and a base metal and outputting a signal representing a current value of the welding current. A welding current average value calculating means for obtaining an average value of the welding current at constant time intervals from a value of an output signal of the welding current detecting means using preset first monitoring condition data for averaging processing And a determining means for determining a welding condition or a welding result from the average value of the welding current obtained by the welding current average value calculating means using second monitoring condition data for preset determination processing. , The first and second for each of the preset starting conditions
Monitoring condition setting means for setting the monitoring condition data of the above, and a monitoring condition storing means for storing the first and second monitoring condition data for each starting condition set by the monitoring condition setting means; Monitoring condition switching means for switching the first and second monitoring condition data used by the welding current average value calculating means and the determining means in response to the switching of the welding conditions of the arc welding to be executed. An arc welding monitor device characterized in that 2. An arc welding monitoring device for monitoring arc welding by an arc welding machine, comprising arc voltage detecting means for detecting an arc voltage between a welding electrode and a base metal and outputting a signal representing a voltage value of the arc voltage. Arc voltage average value calculating means for obtaining an average value of the arc voltage at constant time intervals from an output signal of the welding current detecting means using preset first monitoring condition data for averaging processing, Determining means for determining a welding status or a welding result from the average value of the arc voltage obtained by the welding current average value calculating means using second monitoring condition data for preset determination processing; The first and second conditions are set for each of the set start conditions.
Monitoring condition setting means for setting the monitoring condition data of the above, and a monitoring condition storing means for storing the first and second monitoring condition data for each starting condition set by the monitoring condition setting means; In response to the switching of the welding conditions of the arc welding to be executed, the first and second arc voltage average value calculation means and the determination means respectively use the first and second
Monitoring condition switching means for switching the monitoring condition data of the arc welding monitoring device. 3. The arc welding monitor device according to claim 1, wherein the first monitoring condition data includes data of an averaging time defining the constant time. 4. The arc welding monitor device according to claim 1, wherein the first monitoring condition data includes moving pitch data in a moving average method. 5. The arc welding monitor device according to claim 1, wherein the second monitoring condition data includes data of an upper limit monitoring value or a lower limit monitoring value as a comparison reference value for the average value.