DE102014210699A1 - WELDING CONTROL AND METHOD FOR MONITORING A CLEANING OF A WELDING TOOL AND A DEVICE FOR LEADING A WELDING TOOL - Google Patents

Abstract

There is provided a welding controller (10) and a method for monitoring a cleaning of a welding tool (21) and a device (20) for guiding a welding tool (21). The welding controller (10) comprises a determination device (11) for determining, after a cleaning of the welding tool (21), an actual resistance value and an actual phase angle value of a welding current in a monitoring welding with the welding tool (21), wherein the actual resistance value the resistance of the welding tool (21), which is detected in the monitoring welding with the welding tool (21) on the welding tool (21), and an evaluation device (12) for evaluating whether at least one of the conditions is satisfied that the actual resistance in a tolerance band lies around a reference resistance value and / or that an actual phase angle value is within a tolerance band about a reference phase angle value.

Description

The present invention relates to a welding control and a method for monitoring a cleaning of a welding tool and a device for guiding a welding tool, with which a welded joint can be made, which can be, for example, a spot weld, a weld, etc.

In production plants, such as production lines for vehicles, etc., metallic parts are joined by welding using a welding tool of a welding apparatus. In a welding tool, welding tongs with electrode caps are used in the automated body shop. The electrode caps become soiled by the welding process because the coatings of the sheets to be welded are deposited on the electrode caps. In addition, contamination by the thermal process occurs during welding. Therefore, the electrode caps of the welding gun are to be cleaned at certain time intervals.

The cleaning of an electrode cap is currently carried out by means of a cutting cutter, which cuts off the soiled part of the electrode cap. This process is generally called cap milling or electrode milling. For a stable production process and a consistent welding quality, the functioning and the stability of this process are very important. In production, this process is subject to many disturbances. The cutting blade becomes dull over time, the cutter can clog with the chips produced during milling and thereby adversely affect the cleaning process, or the actual milling process may be too short. For this reason, it is very important to monitor this cleaning process.

The monitoring of the cleaning process is currently at the applicant with the help of a monitoring welding after the cleaning process. The monitoring welding is carried out as a short circuit measurement. The short circuit welding is carried out in the control mode phase control. During monitoring welding, the welding current is detected and from this the mean value over the welding time is formed. This actual current value is compared with two previously stored current reference values. There are user-configurable tolerance limits for these reference values. The actual current value is checked for the limits and an error is triggered if these limits are violated.

Thus, in the described monitoring of the cleaning process, the size of the phase angle of the welding current is set and the magnitude of welding current is recorded or recorded and evaluated. A disadvantage of this approach of monitoring, however, is a large dispersion of the current value. Therefore, the tolerance limits are relatively far to choose. Another disadvantage is that the detection variable welding current even from other wear factors, eg. As the current band wear is affected. As a result, no clear recognition of the quality of cleaning or milling quality of the respective electrode cap is possible. In addition, it is costly and therefore unfavorable that two reference values, good and bad, are necessary for the review.

Therefore, it is an object of the present invention to provide a welding control and a method for monitoring a cleaning of a welding tool and a device for guiding a welding tool, with which the aforementioned problems can be solved. In particular, a welding control and a method for monitoring a cleaning of a welding tool as well as a device for guiding a welding tool are to be provided, in which the monitoring of the cleaning of the welding tool is less complicated, ie simpler, and thereby more precise.

This object is achieved by a welding control for monitoring a cleaning of a welding tool according to claim 1. The welding controller has detection means for detecting, after cleaning the welding tool, an actual resistance value and an actual phase angle value of a welding current in a monitoring welding with the welding tool, the actual resistance being based on the resistance of the welding tool used in the monitoring welding with the welding tool Welding tool is detected on the welding tool, and an evaluation device for evaluating whether at least one of the conditions is satisfied that the actual resistance value in a tolerance band is around a reference resistance value and / or that an actual phase angle value in a tolerance band to a reference Phasenanschnittswert lies.

With the welding control described above, the monitoring of the cleaning of the welding tool can be carried out less consuming but more precise than before. This is based, on the one hand, on the fact that, when monitoring the cleaning of the welding tool, fewer reference values and parameters have to be determined and treated, namely only one reference value. This reference value corresponds to the good case. In the worst case, however, no reference value is needed.

On the other hand, a more accurate error analysis is possible because the resistance is detected directly on the welding tool. It can be distinguished between the errors cleaning quality and current band wear. Thus, when monitoring with the welding control, a distinction is possible as to whether an error on the electrode cap originates from cleaning, in particular milling (milling quality), or from normal wear (current belt wear). This can be used particularly advantageously in aluminum welding, since more scattering and sources of error occur here with the conventional monitoring than with the monitoring carried out by the previously described welding control. As a result, a more accurate error statement than heretofore can be made, and error classes can be defined.

It is also advantageous that the evaluation of the resistance is closer to the process. In addition, tolerance bands can be set tighter.

The welding device described above has less influence on the detection process for monitoring the cleaning of the welding tool, so that with the described welding control a more accurate detection for monitoring the cleaning is possible as in the prior art.

Overall, a very good wear detection is possible with the welding control.

Advantageous further embodiments of the welding control are specified in the dependent claims.

The welding controller may further comprise a first averaging unit for forming a mean value of the welding operation of a reference resistance of the welding tool detected by performing a reference welding, or a mean value on the welding operation of an actual resistance of the welding tool detected when conducting a monitor welding, and a second averaging unit for forming an average value over the welding sequence of a reference phase-angle value of the welding current detected during the execution of a reference welding or an average value over the welding sequence of an actual phase-angle value detected when carrying out a monitoring welding, wherein the evaluation device is designed to evaluate the mean value of the detected actual resistance in the monitoring welding in FIG Reference to a tolerance band around the reference resistance of the reference weld and / or to the evaluation of the mean value d it detected actual phase angle value in the monitor weld with respect to a tolerance band around a reference phase angle value of the reference weld.

Possibly, the averaging units are configured to take into account in the calculation values of the detected resistance, which are detected in the welding process after a predetermined blanking time after the beginning of the welding.

The welding controller may also include an input for receiving information as to whether or not the welding tool is performing a reference weld, a second input for receiving information as to whether or not the welding tool is being monitored, and / or a third input for receiving information a welding tool resistance adjustment after replacement of the welding tool.

The welding controller may have a first output for outputting that a reference weld is active when the first or second input receives information that the welding tool is performing a reference weld or a welding tool resistor trim, a second output for output that a monitor weld is active when the third input receives information that a monitoring weld is being performed with the welding tool and a third output for output that the cleaning operation is faulty if the monitor weld did not complete successfully.

The object is also achieved by a device for guiding a welding tool according to claim 6. The apparatus has an output interface for outputting to an external weld controller when a monitor weld or a reference weld is performed and a controller for controlling a cleaning of the weld tool and a subsequent reference weld and / or monitor weld if the external weld controller evaluates the monitor weld as unsuccessful. In this case, the control device can remain in the standby state during the output that the cleaning process is faulty, so that the device can repeat the faulty cleaning of the welding tool by a new cleaning and subsequent monitoring of the cleaning by the control device. The device achieves the same advantages as previously mentioned with respect to the welding control. The above-described welding control for controlling the welding tool and the above-described device for guiding the welding tool may be part of a welding plant for a production plant The welding system further comprises the welding tool for producing a plurality of welded joints in sequence, the apparatus configured to perform a monitoring welding with the welding tool after cleaning of the welding tool has taken place, and wherein the welding control is configured to judge whether the monitoring welding has been successful or not ,

The welding system can also have a detection device for detecting the actual phase angle value of a welding current and the actual resistance value during a reference welding or monitoring welding with the welding tool, and / or an operating device for operating the welding system and for parameterizing the electrode care of the welding tool and adjustment, and / or the welding system can be designed for welding aluminum.

The object is also achieved by a method for monitoring a cleaning of a welding tool according to claim 10. The method comprises the steps of determining, with a detection device after a cleaning of the welding tool, an actual resistance value and an actual phase angle value of a welding current in a monitoring welding with the welding tool, wherein the actual resistance value based on the resistance of the welding tool, in the Monitoring welding is detected with the welding tool on the welding tool, and evaluating, with an evaluation device, whether at least one of the conditions is met, that the actual resistance value in a tolerance band is around a reference resistance value and / or that an actual phase angle value in a tolerance band to a reference phase angle value is located.

The method achieves the same advantages as mentioned above with respect to the welding control

Further possible implementations of the invention also include not explicitly mentioned combinations of features or embodiments described above or below with regard to the exemplary embodiments. The skilled person will also add individual aspects as improvements or additions to the respective basic form of the invention.

The invention is described in more detail below with reference to the accompanying drawings and to exemplary embodiments. Show it:

1 a highly simplified schematic view of a production plant with a welding system, which uses a device for guiding a welding tool and a welding control according to a first embodiment;

2 a diagram with time histories of resistances of the welding tool, which were detected before cleaning the welding tool and after cleaning the welding tool according to the first embodiment;

3 an example of an input window on an operating device of the welding system according to the first embodiment; and

4 a flowchart of a method that is performed by the welding system and includes monitoring a cleaning of a welding tool according to the first embodiment.

In the figures, identical or functionally identical elements are provided with the same reference numerals, unless stated otherwise.

1 shows a production plant 1 with a welding system 2 , The production plant 1 may be, for example, a production line for vehicles, furniture, structures, etc., in which metallic workpieces 5 . 6 be connected by welding such that a welded joint 7 will be produced. For this purpose, the welding system 2 a welding control 10 , a device 20 for guiding a welding tool 21 , a detection device 30 and an operating device 40 on. The device 20 may be in particular a robot. The operating device 40 For example, it may be a keyboard and / or a mouse, a laptop, a touch-sensitive or touch-screen, etc., or combinations thereof. The welding control 10 has a detection facility 11 with a first and second averaging unit 111 . 112 , an evaluation device 12 , a storage device 13 , an input interface 14 with inputs 141 to 144 and an output interface 15 with outputs 151 to 154 , The storage device 13 serves to store internal basic parameters or setpoints of a welding process with the welding tool 10 , either factory or later with the help of the operating device 40 can be entered by a user. The internal basic parameters or setpoints can be parameters of the welding tool 10 be. In addition, the internal basic parameters or setpoints can be parameters of the welding control 20 be, with which the welding tool 10 is controlled. In particular, the internal basic parameters or setpoints are a phase angle of the welding current I and a resistance R of the welding tool 21 when performing a weld.

In addition, if necessary, the detection data of the detection device 30 over a connecting line 31 to the welding control 10 transferred and in the storage device 13 get saved. In addition, the determination device 11 on the storage device 13 access and data in the storage device 13 save or retrieve data from it. The same applies to the first and second averaging unit 111 . 112 , Likewise, the evaluation 12 on the storage device 13 access and data in the storage device 13 save or retrieve from it.

The device 20 for guiding the welding tool 21 provides as a welded joint 7 For example, a weld point and / or a weld forth. This allows two metallic components, such as the workpieces 5 . 6 to be connected with each other. The welding tool 10 For example, a welding tongs with at least one electrode cap 22 . 23 be. The electrode cap 11 can for example be made of copper-chromium-zirconium (CuCrZr). When guiding the welding tool 21 with her arm 24 becomes the device 20 from their controller 25 controlled. This is the control device 25 with the welding control 10 via an input interface 26 with inputs 261 to 263 with the help of a first connection line 27 and via an output interface 28 with outputs 281 to 283 with the help of a second connecting line 29 connected. Over the connecting lines 28 . 29 can provide relevant data for performing a weld with the welding tool 21 between the welding control 10 and the device 20 More specifically, the controller 25 , be replaced. In addition, the internal basic parameters or setpoints in the memory device 13 Parameters of the control device 25 be, with which the welding tool 10 is controlled.

The welding tool 10 can with a cleaning device 50 , which may be embodied as a milling or cutting device or exchange device, are processed such that the soiled part of one of the electrode caps 22 . 23 if necessary cut off or milled off. This cleaning with the cleaning device 50 is also from the controller 25 at the behest of the welding control 10 controlled as described in more detail below.

Generally speaking, the detection means receives 11 from the detection device 30 the detection results with respect to welds made with the welding tool 21 be carried out, and the evaluation 12 evaluates the detection results as described below. In this case, the settings required for the welding operations or welds on the operating device 40 produced. The evaluation results are the controller 25 for the control of the welding tool 21 made available.

Comes the welding control 10 to the conclusion that a cleaning of at least one of the electrode caps 22 . 23 is to be executed, it signals the result of the control device 25 over the connecting line 27 , The control device 25 in turn gives feedback on the control it has performed over the trunk 29 to the welding control 10 back.

As in 1 shown has the welding control 10 for communication between the welding control 10 and the controller 25 and thus the device 20 the three entrances 142 . 143 . 144 with which of the device 20 the following additional functions can be called up via correspondingly set input bits:
entrance 142 : Reference welding of a new or cleaned electrode or electrode cap (s) 22 . 23 , Will the entrance 142 from the controller 25 over the connecting line 29 set as active, the welding control interprets 10 the next sequence, ie the cleaning program, as a reference weld. The resistance and phase angle value (average values) is stored as the respective reference value for a new electrode, ie a "good cleaning", in particular "good milling". For the bad case, so a "poor cleaning", however, no reference value is needed.

entrance 143 : Welding tool resistance adjustment
With the entrance 143 can, after a change to the welding tool 21 or an exchange of the welding tool 21 , the welding tool 21 be recalibrated. For the calibration of the welding tool 21 A short-circuit welding with the cleaning program is also necessary. The actual value of the resistance R and the actual value of the phase angle of the welding current I in this calibration sequence are then also used as reference values for the corresponding electrode or the electrode caps 22 . 23 stored.

entrance 144 : Monitoring welding of an electrode or the electrode caps 22 . 23 after cleaning becomes the entrance 144 from the controller 25 over the connecting line 29 set as active, the welding control interprets 10 the next welding process as a monitoring weld after cleaning what in terms of Steps S7 to S9 according to 4 described below. The respective mean values of the resistance value and the phase angle value of this welding sequence are checked for the two reference values and the result reported.

In addition, the welding control has 10 the following outputs 152 to 154 , so that the device 10 the previously described functions can be signaled via correspondingly set output bits or, thus, the device 10 to monitor the functions described above.

output 152 : "Reference welding active"
When the device 20 over the entrance 142 "Reference welding of a new electrode" or 143 "Welding tool resistance compensation" triggers a reference weld is from the welding control 10 after the start until the beginning of the step S2 following step the output 153 set with the function "reference welding active".

The device 20 can, as in a normal sequence, via outputs, not shown, "advance contact", "ready" and "welding error" of the welding control 10 check if the reference weld was successful or not. This is particularly important in this case, as a faulty reference welding is later checked for a faulty setpoint. In the event of a fault, therefore, the reference weld should be repeated.

output 153 : "Monitoring welding active"
When the device 20 over the entrance 144 "Monitoring welding of an electrode after milling" a monitoring welding according to the following steps S7 to S9 of 4 is triggered by the control device 25 after starting until the beginning of step S9 of 4 following step the output 153 set with the function "Monitoring welding active".

The device 20 can, as in a normal sequence, via outputs, not shown, "advance contact", "ready" and "welding error" of the welding control 10 check whether the monitoring welding was successful or not. These outputs can be a general error, eg. As a temperature error, etc., be signaled, which prevents the actual monitoring. If the controller remains in the "ready" state and a "continuation contact" is output, the process was OK. However, these general outputs say nothing about the monitoring result.

output 154 : "Milling process incorrect"
After successful completion of a monitoring weld, the device must 20 Evaluate the output "Milling process incorrect". The exit 154 is set or activated at the end of a (successful) run until the beginning of the next run, if the evaluation via the reference values has revealed that the cleaning process was defective according to the criteria mentioned above. Remains the exit 154 inactive, the surveillance was fine.

Accordingly, the welding control sends 10 over the exits 152 to 154 the welding control 10 and the entrances 261 to 263 the control device 25 corresponding messages to the controller 25 , The messages can, for example, the evaluation results of the evaluation 12 be.

In addition, the device has 20 to carry out and monitor the functions described above the inputs 261 to 263 and the outputs 281 to 283 , With the entrances 261 to 263 and the outputs 281 to 283 Can the from the device 20 functions are signaled via appropriately set output bits.

2 shows an example of the course of a resistance value R of the welding tool 21 over time t, and for one before cleaning the electrode cap (s) 22 . 23 from the detection device 30 detected resistance value RA and for one after a cleaning of the electrode cap (s) 22 . 23 from the detection device 30 detected resistance RB. As a result, the resistance value R of the welding tool increases 21 after performing a weld tends to decrease. As well as out 2 can be seen, the resistance value R of the welding tool 21 in the course of a weld initially approximately exponentially and after a blanking time A is approximately constant. In this case the resistance value RA precedes a cleaning of the electrode cap (s) 22 . 23 faster to the approximately constant value than the resistance RB after a cleaning of the electrode cap (s) 22 . 23 ,

3 shows an example of an input mask 45 , which at the operating device 40 is displayed so that a user can monitor and, if necessary, enter and / or change the aforementioned internal basic parameters or setpoints. The in the input mask 45 The internal basic parameters or setpoint values displayed are the welding current I, the welding voltage U, the current time t_I, the energy E, the process stability S, the power P, the phase angle PHA and the resistance R. The monitored variable UIP stands for the quality factor resistance and the quantity FQF for the quality factor force.

In 3 the specified internal basic parameters or setpoints and specifications are assigned to each

LIST OF REFERENCE NUMBERS

101

Monitoring, whether monitoring takes place or not

102

reference value

103

Absolute tolerance bands

104

Permissible tolerance band above

105

Upper conditional tolerance band

106

Lower conditional tolerance band

107

Permissible tolerance band below

The tolerance bands, ie the values too 103 to 107 are usually used by the user at the operating device 40 entered. However, it is already possible for the manufacturer to set basic values in advance.

The respective required parameters are electrode-specific.

• • Oberes Toleranzband Widerstand für neue Elektrode bzw. neue Elektrodenkappe(n)
• • Unteres Toleranzband Widerstand für neue Elektrode bzw. neue Elektrodenkappe(n)
• • Oberes Toleranzband Phasenanschnitt für neue Elektrode bzw. neue Elektrodenkappe(n)
• • Unteres Toleranzband Phasenanschnitt für neue Elektrode bzw. neue Elektrodenkappe(n)

For example, you can parameterize:

• • Upper tolerance band resistance for new electrode or new electrode cap (s)
• • Lower tolerance band resistance for new electrode or new electrode cap (s)
• • Upper tolerance band Phase control for new electrode or new electrode cap (s)
• • Lower tolerance band Phase control for new electrode or new electrode cap (s)

• • Referenzwert Widerstand für neue Elektrode bzw. neue Elektrodenkappe(n)
• • Referenzwert Phasenanschnitt für neue Elektrode bzw. neue Elektrodenkappe(n)

The tolerance band parameters are considered "normal" parameters so that they are taken into account in the backup and their change is recorded in the data modification log. In contrast, in this example, the following parameters are generated automatically as follows 4 and step S2 described:

• • Reference value resistance for new electrode or new electrode cap (s)
• • Reference value phase cut for new electrode or new electrode cap (s)

As below in relation to 4 and step S2, the parameters for the reference values are generated internally after a welding process, the reference welding, from the measured actual values. They are taken into account in the backup and their change is recorded in the data change log.

If only a part of the check is to be used, for example only the check for the reference value resistance, the user just simply does not need to make any further inputs for the other type of monitoring (reference value phase control).

4 Illustrates in a flowchart a flow of a process that in the production plant 1 from the welding system 2 is carried out.

After the start of the process, the welding tool is at a step S1 21 set up for welding. Here are the correct and the new electrode caps 22 . 23 on the welding tool 21 mounted so that the welding tool 21 ready to perform a weld. Thereafter, the flow proceeds to a step S2.

In step S2, the welding tool is used 21 a reference welding and / or a monitoring welding on the electrode caps 22 . 23 carried out. This can also be checked if the welding tool 21 at step S1 has been set up correctly. The welding is performed in short circuit in the control mode phase control.

Is the welding tool 21 properly set up, reports the controller 25 to the welding control 10 that with the welding tool 21 a reference weld is performed. The distinction as to whether the welding process is used as a reference welding or as a monitoring welding, in this embodiment, based on input bits of the inputs 142 to 144 which the user or user must set before the program run, as described above.

The detection device 30 detects the resistance R in the welding tool in the course of the reference welding 21 by detecting the welding voltage U. In addition, the detecting means detects 30 in the course of the reference welding, the phase angle value of the welding current I. The detected values are transmitted via the connecting line 31 to the welding control 10 for storage in the storage device 13 forwarded. The storage device 13 stores the transferred values as reference values or as internal basic values, which can subsequently be used in a monitoring welding. Instead of the reference welding, basic values can already be set in the memory device for all parameters ex works 13 be deposited.

Thus, the reference values become when welding a defined welding program with the detection device 30 certainly. This welding program can be individually created by the user or user.

The welding program will usually be a short circuit measurement. In this program a sequence with the operating mode KSR ( Constant current control) can be programmed without readjustment and without power correction. This program is the electrode to be monitored and thus the electrode cap to be monitored 22 . 23 of the welding tool 21 assigned.

Is the reference weld completed and thus the welding tool 21 ready to carry out in the production plant 1 required welds, the flow proceeds to a step S3.

In step S3, the device performs 20 under control of the controller 25 according to the specifications of the welding control 10 a weld for making a weld 7 out. Thereafter, the flow proceeds to a step S4.

In step S4, a wear counter is incremented. Thereafter, the flow proceeds to a step S5.

In step S5, it is checked whether the maximum number of welds with the electrode caps 22 . 23 was performed and therefore the electrode caps 22 . 23 to clean or not. If no cleaning is yet to be performed, the flow returns to step S3. On the other hand are the electrode caps 22 . 23 to purify, the flow proceeds to a step S6.

In step S6, the electrode caps become 22 . 23 with the cleaning device 50 cleaned, for example with milling cutters, or the electrode cap (s) 22 . 23 will / will be replaced by suitable newer electrode cap (s) 22 . 23 replaced. Thereafter, the flow proceeds to a step S7.

Step S7 and subsequent steps S8 and S9 monitor the cleaning of the electrode caps 22 . 23 with the cleaning device 50 carried out.

In step S7, the welding controller detects 10 after cleaning the electrode caps 22 . 23 the cleaning result. The detection takes place with the aid of the detection variables resistance R in the welding tool 21 by detecting the welding voltage U and phase angle of the welding current I in the monitoring welding, which detection variables from the detection device 30 when performing a weld. Like the reference values in step S2, the actual values also become when welding a defined welding program with the detection device 30 certainly. The welding program for the monitoring welding can also be individually created by the user or user.

In order to display the welding process as a monitoring weld, in this exemplary embodiment, the user or user sets the corresponding input bit before the program sequence, as already mentioned with reference to step S2 and previously described in more detail.

The welding control 10 required to carry out the monitoring previously with respect to the step S2 and 3 reference values and tolerance limits or bands as well as the detection variables resistance R and phase angle of the welding current I detected in the monitoring welding as actual values. As already mentioned, the tolerance limits or tolerance bands are via the operating device 40 parameterized by the user, as well as off 3 evident. Thereafter, the flow proceeds to step S8.

In step S8, the welding control performs 10 with the investigator 11 and the averaging units 111 . 112 as well as the evaluation device 12 two exams.

For this purpose, the averaging units are used for both data entry quantities 111 . 112 separately formed the average over the welding process. In the calculation, the blanking time A, which is in 2 is shown as an example, defined at the beginning of the welding process of the weld.

Thus, on the one hand, the first averaging unit determines 111 the mean value of the actual resistance, more precisely the actual resistance value, the monitoring welding. The evaluation device then checks 12 the mean value of the actual resistance of the monitoring welding against the reference resistance of the new electrode or the new electrode cap (s) 22 . 23 , In this case, after a correct cleaning operation, the actual resistance of the monitoring welding (after cleaning) is approximately equal to the reference resistance of the new electrode or the new electrode cap (s). 22 . 23 should correspond. For this purpose, the reference resistance R of the reference welding of the new electrode or the new electrode cap (s) 22 . 23 provided with a programmed tolerance band and compared with the actual resistance detected during the monitoring welding.

On the other hand, the second averaging unit determines 112 the mean value of the actual phase angle, more precisely the actual phase angle value, of the welding current I in the monitoring welding and the evaluation device 12 checks the mean value of the actual phase angle of the welding current I against the reference phase angle of the welding current I at the new electrode or the new electrode cap (s) 22 . 23 , In this case, after a correct cleaning operation, the actual phase angle value of the welding current I during the monitoring welding (after cleaning) is approximately equal to the reference phase angle value of the new electrode or the new electrode cap (s). 22 . 23 should correspond. For this purpose, the reference phase angle value of the reference welding according to the step S2 of the new electrode or the new electrode cap (s) 22 . 23 with the programmable tolerance band ( 3 ) and compared with the detected during the monitoring welding actual phase angle value of the welding current I.

Is in accordance with an evaluation by the evaluation 12 If, in at least one of the two tests, the result is outside the corresponding tolerance band, the flow proceeds to step S9. Otherwise, if the monitoring weld was OK, the flow returns to step S2, so that for the cleaned electrode or the cleaned electrode cap (s) 22 . 23 the reference welding performed and then with the regular welding of the workpieces 5 . 6 can be started for production.

At the step S9, the welding control is executed 10 an error message to the controller 25 output. However, the controller considers 25 such an error message as a result of faulty cleaning as a "warning" and not as an "error", in which the device 20 leaves the standby state. For example, the ready signal is not removed. Therefore, no extra error must be reset. Instead, the flow returns to step S6, so that the device 20 has the opportunity to repeat a faulty cleaning immediately afterwards. The warning is also sent to the operating device 40 reported and displayed there.

The process is finished when the welding system 2 and / or the production plant 1 is turned off.

According to a second embodiment, the welding control has 10 no input described above 143 , Thus, here no welding tool resistance balance with the welding control 10 be executed. Otherwise, the production plant 1 and the fucking thing 2 constructed as described with respect to the first embodiment.

All previously described embodiments of the welding system 2 , the welding control 10 , the device 20 for guiding the welding tool 21 and the method can be used individually or in all possible combinations. In particular, all features and / or functions of the embodiments described above can be combined as desired. In addition, the following modifications are conceivable, in particular.

The parts shown in the figures are shown schematically and may differ in the exact embodiment of the shapes shown in the figures, as long as their functions described above are guaranteed.

The number of inputs and outputs of the welding controller 10 and the controller 25 is arbitrary.

Claims (10)

Welding control ( 10 ) for monitoring a cleaning of a welding tool ( 21 ), with an identification device ( 11 ) for determining, after a cleaning of the welding tool ( 21 ), an actual resistance value and an actual phase angle value of a welding current in a monitoring welding with the welding tool (FIG. 21 ), wherein the actual resistance value on the resistance of the welding tool ( 21 ) used in monitoring welding with the welding tool ( 21 ) on the welding tool ( 21 ), and an evaluation device ( 12 ) for evaluating whether at least one of the conditions is satisfied that the actual resistance value is within a tolerance band about a reference resistance value and / or that an actual phase angle value is within a tolerance band about a reference phase angle value. Welding control ( 10 ) according to claim 1, further comprising a first averaging unit ( 111 ) for averaging over the welding sequence of a reference resistance of the welding tool detected when carrying out a reference welding ( 21 ) or an average value over the welding sequence of an actual resistance of the welding tool detected when performing a monitoring welding ( 21 ), and a second averaging unit ( 112 ) for forming an average over the welding sequence of a reference phase angle value of the welding current detected when carrying out a reference welding or an average value over the welding sequence of an actual phase angle value detected when carrying out a monitoring welding, wherein the evaluation device ( 12 ) is configured for evaluating the average of the detected actual resistance in the monitoring welding with respect to a tolerance band around the reference resistance of the reference welding and / or for evaluating the average value of the detected actual phase angle value in the monitoring welding with respect to a tolerance band around a reference Phase angle value of the reference weld. Welding control ( 10 ) according to claim, wherein the averaging units ( 111 ; 112 ) are designed in such a way to take into account in the calculation average values, which are detected in the welding process after a predetermined blanking time (A) after the beginning of the welding. Welding control ( 10 ) according to any one of the preceding claims, further comprising an input ( 142 ) for receiving information, whether with the welding tool ( 21 ) a reference welding takes place or not, a second input ( 143 ) for receiving information, whether with the welding tool ( 21 ) a monitoring welding takes place or not, and / or a third input ( 144 ) for receiving information of a welding tool resistance adjustment after replacement of the welding tool ( 21 ). Welding control ( 10 ) according to any one of the preceding claims, further comprising a first output ( 152 ) for outputting that a reference weld is active when the first or second input ( 142 . 143 ) Receives information that with the welding tool ( 21 ) a reference welding or a welding tool resistance adjustment is performed, a second output ( 153 ) for outputting that a monitoring weld is active when the third input ( 144 ) Receives information that with the welding tool ( 21 ) a monitoring welding is performed, and a third output ( 154 ) indicating that the cleaning operation is faulty if the monitor welding did not complete successfully. Contraption ( 20 ) for guiding a welding tool ( 21 ), with an output interface ( 28 ) for output to an external welding control ( 10 ), when a monitor weld or a reference weld is performed, and a controller ( 25 ) for controlling a cleaning of the welding tool ( 21 ) and a subsequent reference welding and / or monitoring welding, when the external welding control ( 10 ) rated the monitoring weld unsuccessful. Contraption ( 20 ) according to claim 6, wherein the control device remains in the standby state upon output that the cleaning process is faulty, so that the device ( 20 ) the faulty cleaning of the welding tool ( 21 ) by a new cleaning and subsequent monitoring of the cleaning by the control device ( 25 ) can repeat. Welding system ( 2 ) for a production plant ( 1 ), with a welding tool ( 21 ) for producing a plurality of welded joints ( 7 ) successively, a welding control ( 20 ) according to one of claims 1 to 5 for controlling the welding tool ( 21 ), and a device according to one of claims 6 or 7 for guiding the welding tool ( 21 ), the device ( 20 ) is configured to perform a monitoring welding with the welding tool ( 21 ), after a cleaning of the welding tool ( 10 ), and wherein the welding control ( 20 ) is designed to evaluate whether the monitor weld was successful or not. Welding system ( 2 ) according to claim 8, further comprising a detection device ( 30 ) for detecting the actual phase angle value of a welding current and the actual resistance value during a reference welding or monitoring welding with the welding tool ( 21 ), and / or an operating device ( 40 ) for operating the welding system ( 2 ) and for the parameterization of the electrode care of the welding tool ( 21 ) and adjustment, and / or wherein the welding system ( 2 ) is designed for welding aluminum. Method for monitoring a cleaning of a welding tool ( 21 ), with the steps of determining (S7), with a determination device ( 11 ) after cleaning the welding tool ( 21 ), an actual resistance value and an actual phase angle value of a welding current in a monitoring welding with the welding tool (FIG. 21 ), wherein the actual resistance value on the resistance of the welding tool ( 21 ) used in monitoring welding with the welding tool ( 21 ) on the welding tool ( 21 ), and evaluating (S8), with an evaluation device ( 12 ), whether at least one of the conditions is met, that the actual resistance value is within a tolerance band around a reference resistance value and / or that an actual phase angle value is within a tolerance band around a reference phase angle value.

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