JPH06339778A - Diagnosis method of welding machine - Google Patents

Abstract

PURPOSE:To provide the diagnosis method of a welding machine capable of quickly detecting the abnormality of a welding machine and quickly judging the advisability of operation of an equipment in spite of the change of welding endition and steel class. CONSTITUTION:The abnormality of working numerical values in terms of a welding current, welding speed, pressing force of electrode ring, etc., at resistance welding of steel and the abnormality by trend value control based on the specific reference value are quickly detected as an alarm output. At outputting alarm, various factor related to the abnormal phenomenon in terms of equipment of welding machine and the guidance to cope with these abnormal factor are diagnosed based on the guidance function to output/display in occurrence rate sequence of each factor. By this method, when the advisability of operation of equipment is quickly judged, the timing of starting and completing for comparative analysis and calculation of variance are set at each output in plural with the same output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for diagnosing a welding machine during resistance welding of a steel material, and in particular predicts an abnormality of the welding machine from fluctuations in measured values of welding current and welding voltage, and further measures each of these measured values. This is a proposal for a method for specifically diagnosing the equipment abnormality state of the welding machine from the trend value management data accumulating the variation of

[0002]

2. Description of the Related Art Generally, in resistance welding such as seam welding, as shown in FIG. 1, current is applied to a joint portion of materials to be welded (base material) 2 which are superposed via an electrode 1, and a resistance heating melting portion ( This is a technique in which both base materials are welded through the nugget 3 by forming the nugget) 3. Therefore, since the formation state of the nugget 3 is a factor that greatly affects the welded portion quality such as welding strength, the operating state of the resistance welding machine that affects the formation state of the nugget 3, that is, the welding current and the welding current. It is extremely important to control the welding machine operating values such as voltage.

As a technique for diagnosing the welding state or the state of welding equipment by managing the operating values of the welding machine such as welding current and welding voltage, for example, Japanese Patent Laid-Open No. 3-32474 is available.
In the gazette, for each welding, the output signal of the welding machine operation value such as welding current and welding voltage is input to calculate the amount of electric power input to the welding machine, and this electric amount is compared with a preset reference value. By doing so, a method for detecting an abnormality in the welding machine operation value such as welding current and welding voltage, and consequently an abnormality in the welding state is disclosed.

[0004]

The above-mentioned prior art is a method of comparing a welding machine operation value such as welding current and welding voltage with a reference value by using an absolute value for each welding. It is effective to detect the occurrence of equipment abnormalities during the same single welding, but if the plate thickness of the material to be welded or the type of steel changes, the welding conditions also change, so the above reference values must be changed. I won't. That is, if this reference value is left as it is for diagnosis, a malfunction may occur, such that the equipment may be normal but abnormal.

Therefore, conventionally, it is also necessary to change the above-mentioned abnormality diagnosis reference value in accordance with changes in welding conditions such as steel type and plate thickness, so that not only trend management based on a specific reference value becomes impossible. However, there is a drawback that it is not possible to promptly grasp the tendency regarding whether or not the welding machine operates.

Therefore, the present invention is intended to overcome the drawbacks of the above-mentioned conventional techniques, and in particular, regardless of changes in welding conditions and steel grades, abnormalities in welding machine operating values such as welding current and welding voltage, In other words, while quickly detecting a welder abnormality, by controlling the trend value of the abnormal state based on a specific reference value, it is possible to quickly determine whether the equipment should operate or not, and to take prompt and appropriate measures against the equipment abnormality of the welder. The purpose is to propose a welding machine diagnostic technique that can be used.

[0007]

As a result of earnest research for achieving the above object, the inventors of the present invention have found that, when paying attention to variations in welding machine operating values such as welding current and welding voltage at each welding, According to the management by the variation, it is found that the tendency value management of the abnormal state by each detected value can be performed without the need to change the reference value for diagnosis as in the prior art, and this tendency value management is performed. By displaying the concrete countermeasures based on the equipment abnormality on the CRT etc. as a guidance function, it is possible to promptly judge the propriety of equipment operation and take prompt and appropriate measures for the equipment abnormality of the welding machine. As a result, the inventors have come up with the method of the present invention as described below.

That is, according to the present invention, welding machine operation numerical values such as welding current, welding voltage, welding speed, and electrode wheel pressing force at the time of resistance welding of steel materials are output and compared and analyzed with a preset reference value. To detect the equipment abnormality of the welding machine as an alarm output, and to calculate these variations from the maximum value, the minimum value and the average value of at least one or more of the above-mentioned operation values, and to compare them with a preset reference value. By managing tendency values under comparison, when judging whether the equipment is operating or not, it is possible to set multiple start times and end times for the above comparative analysis and calculation of variations for each output, with the same output. This is the welding machine diagnosis method.

[0009]

FIG. 2 is a system configuration diagram showing an embodiment of a welding machine diagnosis method according to the present invention. The welding machine operating values such as welding current, welding voltage, and welding speed are shown at each welding. , The abnormality of the welding machine is detected by comparing with the preset reference value respectively, and the fluctuation (variation) of the measured value is evaluated under the trend value control, and the abnormality of the welding machine is detected and its equipment It is a system that makes a quick decision as to whether or not to start operation.

In this figure, at each welding,
Output signals of welding machine operation numerical values such as welding current and welding voltage having waveforms as shown in FIG. 3 measured at high speed are input to the storage device 4, respectively. Next, from the data signal accumulated in the storage device 4, the variation calculation circuit 5 calculates the variation σ = (maximum value−minimum value) / average value and inputs it to the abnormality detection circuit 6 and the tendency value management determination circuit 7. Then, the abnormality of the welding machine is always detected online.

That is, the abnormality detection circuit 6 detects the facility abnormality of the welding machine at each welding time by comparing the input value and the reference value with an absolute value, while the tendency value management determination circuit 7 , Based on the output signal of the equipment abnormality, as shown in FIG. 4, the variation σ accumulated at every welding,
The tendency value management data is compared with a specific reference value, and this tendency value management data is output to a CRT or the like (not shown). From the result, the propriety of equipment operation is judged.

Here, as shown in FIG. 5, the welding machine operating signals such as welding current and welding voltage for each welding are changed in state depending on the position of the electrode 1. , The interval for calculating the maximum value, the minimum value and the average value used to calculate the variation σ can be set individually for each operation signal, the timing of the calculation start and the calculation end is The operation start and end are performed by comparing the operation signal value with the operation start reference and operation end reference of each operation signal value set in advance.

A concrete example of this method is shown in FIG. First, in FIG. 6, the system shown in FIG. 2 is in a standby state for signal input by performing memory clear for signal collection and calculation. In this state, when an operation start signal is input, each operation signal is input and the signals are collected. next,
When the position of the electrode wheel 1 shown in FIG. 5 reaches B or C, in order to start extraction of the maximum value and the minimum value of each operation signal and calculation of integration of the signal, each operation signal and a preset calculation Compare with starting criteria.

Further, when the electrode wheel 1 reaches the position E or F in FIG. 5, in order to finish the extraction of the maximum value and the minimum value of each operation signal and the integration calculation of the signal, each operation signal and the operation signal are previously set. Compare the set calculation end criteria. The average value is calculated from the integrated value of each operation signal calculated according to the above procedure, then the variation value is calculated from the maximum value and the minimum value, and the variation σ is finally calculated.

(Accordingly, according to the present invention, the operator can grasp the cause of the abnormality in the equipment of the welding machine and the corresponding guide for eliminating the cause at an early stage, and can promptly know whether or not the equipment operates. In this way, it is possible to take prompt measures against abnormalities.By this, the operation stop for adjusting the equipment of the welding machine is also the minimum necessary, the welding fracture of steel material can be significantly reduced, the welding accuracy is improved and the product is improved. (The yield can be improved, and the line availability can be greatly improved.)

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A welding machine diagnosis method according to the present invention will be described with reference to FIGS.
Based on the above, an example applied to a seam welding machine installed on the inlet side of a continuous processing line for steel strips will be described. It should be noted that, as shown in FIG. 1, welding using this seam welding machine is performed by superimposing the tail end portion of the preceding steel strip and the tip end portion of the trailing steel strip on top of each other, and superposing the superposed portion on top and bottom electrodes. It is carried out by moving the steel strip in the width direction while applying pressure by the wheel 1.

In the welding machine diagnosis method of the present invention, first, operation signals such as welding current, welding voltage, welding speed (peripheral speed of the electrode wheel) and pressure of the electrode wheel during seam welding are measured, and each measured value is measured. To each storage device 4. In FIG. 3, for example, the welding current is measured in a cycle of 3 ms, the horizontal axis indicates time or the position in the width direction of the steel strip, 8 indicates a raw signal, and 9 indicates a measurement point.

Next, each data signal thus accumulated in the storage device 4 is input to the variation calculation circuit 5.
The timing of the start and end of this input was set as follows for each signal.

That is, first, the welding current is input to the variation calculation circuit 5 at the position B of the electrode wheel 1 in FIG. Termination criteria were set at 4 kA each. Next, the welding voltage was set to 2 V so that the input was started at the position C of the electrode wheel 1 in FIG. 5 and the input was similarly ended at the position E. The welding speed is set so that the welding speed starts to be input at the position B of the electrode wheel 1 in FIG.
It was set to 14 m / min. Further, the electrode wheel pressure is as shown in FIG.
The input was started at the position B of the electrode wheel 1 and the input was similarly ended at the position F.

The variation calculation circuit 5 to which each data signal is input in this manner calculates the variation σ of each data signal for each welding, and the result is sent to the abnormality detection circuit 6 and the tendency value management determination circuit 7. input.

As in the prior art, the abnormality detection circuit 6 detects the facility abnormality of the welding machine by comparing the input value and the reference value with an absolute value. That is, when the input value exceeds the reference value, it is detected that there is an abnormality in the welding machine, which serves as a trigger signal to display an alarm or the like.

On the other hand, in the trend value management judgment circuit 7, the trend value management data obtained by comparing the variation σ with a specific reference value is detected and displayed on a CRT or the like, and from the result, it is judged whether the equipment is operating or not. To do.

By the above procedure, the operator can promptly take appropriate measures against the abnormality such as performing inspection and repair offline without being confused by the plurality of abnormality factors displayed on the CRT and the abnormality response guide. You can take it.

[0024]

As described above, according to the welding machine diagnosis method of the present invention, regardless of changes in welding conditions and steel types,
Abnormalities in the welding machine operating values such as welding current and welding voltage, that is, abnormalities in the welding machine can be detected promptly, and the pros and cons of equipment operation can also be promptly determined by trend value management based on specific reference values. Therefore, it is possible to prevent welding breakage of the steel material during welding, and it is possible to significantly improve the line operation rate.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the principle of seam resistance welding.

FIG. 2 is a system configuration diagram showing an embodiment of a welding machine diagnosis method according to the present invention.

FIG. 3 is a diagram showing an example of an input signal obtained by measuring a welding current in a cycle of 3 ms.

FIG. 4 is a diagram showing an output example of trend value management data of variation σ.

FIG. 5 is an explanatory diagram showing each actuation signal and time setting of start and end of calculation of each signal.

FIG. 6 is an explanatory diagram of a processing flow of each operation signal.

[Explanation of symbols]

 1 Electrode 2 Welding Material 3 Nugget 4 Storage Device 5 Variation Calculation Circuit 6 Abnormality Detection Circuit 7 Trend Value Management Judgment Circuit 8 Raw Signal 9 Measurement Points

Claims (1)

[Claims] 1. A welding machine operating numerical value such as a welding current, a welding voltage, a welding speed, a welding force of an electrode wheel, etc., during resistance welding of a steel material is output and compared with a preset reference value to analyze the welding machine. Equipment abnormality is detected as an alarm output, and these variations are calculated from the maximum value, minimum value and average value of at least one or more of the above operating values of each output, and then compared with a preset reference value. Welding machine characterized by setting the timing of start and end of the above comparative analysis and calculation of variation for each output with the same output when judging whether or not to operate the equipment by controlling the tendency value Diagnostic method.