【 Abstract 】 : The automatic arc welding robot workstation is generally composed of arc welding robot and controller, peripheral operators linkage mechanism and welding power supply. When troubleshooting equipment, equipment maintenance can be carried out according to the fault code and in combination with each module.

The automatic arc welding robot workstation is generally composed of arc welding robot and controller, peripheral operators linkage mechanism and welding power source. When troubleshooting equipment, equipment maintenance can be carried out according to the fault code and in combination with each module.

1. Failure of the moving part of arc welding robot

The fault occurs in the motion position of arc welding robot, and the general alarm code is SRVO. In case of the fault alarm, each servo unit and the corresponding control line shall be checked. The following is illustrated with two examples.

(1)FANUCM -- 10I arc welding robot is equipped with R-30IB control system. In the course of operation, the control system stops suddenly and the alarm appears: SRVO-021 SRDY OFF(G∶2 A∶1).

First, reset the alarm and found it could not be reset. The reason for checking the alarm is that the group shown and the ready signal of the servo amplifier corresponding to the shaft are turned off. Due to the normal use of the equipment in the early stage, the reason of the change of axle number, amplifier number and amplifier type is excluded. According to the group displayed by the alarm number, it can be seen that it is the external rotation axis of the arc welding system. Firstly, check the interlocking switch of the external axes of the equipment, and no fault is found. According to the preliminary judgment, the fault should be at the first servomotor of the rotating shaft outside the equipment.

In order to further determine the cause of the fault, the measured side lock voltage of the servo motor was 0V, while the side lock voltage of the servo amplifier was 24V. It was judged that the servo motor lock was not opened, leading to the alarm of the device controller. Further inspection of the cables showed that the servo motor encoder wire and brake lock wire were worn and broken. After the encoder line is replaced and the brake line is locked, the alarm number is displayed as SRVO-062 BZAL abnormal (G∶2 A∶1) after the alarm is reset and the zero point of the shaft is calibrated, and the equipment returns to normal.

(2) Shutdown of FANUCM -- 10I arc welding robot in the process of automatic operation and alarm: SRVO-046 OVC abnormal (G:2 A:1)SRVO-024 moving error is too large (G:2 A:1)SRVO- 124 Confirm mechanical plug (G:2 A:1).

The operator reported that the alarm occurred in the early stage and could be reset, but it could not be reset this time. According to the alarm number, the main alarm should be srVO-046 OVC anomaly (G∶2 A∶1). The fault reason for checking the alarm number is that the root mean square current value calculated inside the servo device exceeds the maximum allowable value. To protect the motor and amplifier from heat damage, issue this alarm. The possible causes are mainly servo motor lock, power supply and overload.

The possible reason for the fault is that the servo motor's current is too large during operation, which leads to alarm and overload. Check the lock brake, power supply and coil according to the cause of the fault. However, it is found that the power line of an external shaft servo motor is worn during the line inspection. The reason is that the fault may occur on the ground during the vibration of the line.

But the equipment is running after a period of time there is still a the alarm, analysis may be a servo motor fault, remove the servo motor in the case of no load test run, no alarm, but in the discovery in the operation of the servo motor axis swing, thus concludes that the location speed reducer failure, remove the reducer found reducer jammed, equipment normal after replacement of speed reducer.

2. Arc welding locating program fault of arc welding robot workstation

Arc welding program failure of arc welding robot workstation, the alarm prefix of such failure is generally THSR, and the parameter setting, hardware connection and register status related to the search should be checked emphatically for such failure. The following is illustrated with two examples.

(1)FANUCM -- 10I arc welding robot is equipped with R-30IB control system. It is reported that thSR-030 has not been searched and the products have been touched. Srvo-126 Quiqe stop error (G∶1).

According to the analysis, the main reason for the two alarms should be that the SRVO-026 fault occurs only after the equipment stops after the FAILURE of THSR-030. Therefore, the reason for the failure of THSR-030 is found as follows: Before the search action starts, the wire contacts the parts.

Countermeasures as follows:

Check the parts box wiring or teach the new search start location. Due to the existence of seeking in the fault of the arc welding program and the existence of electrical signal exchange between parts and arc welding robot in the analysis of seeking, it was decided to check the electrical signal exchange circuit. However, no electrical circuit was found in the electrical signal exchange process, so the analysis may carry out signal transmission through the welding wire.

During the inspection of the welding wire, it was found that the wire feeding hose fell off and the welding wire came into contact with the equipment support frame, which was an integral whole with the parts and fixtures. Therefore, the contact between the welding wire and the parts formed a signal loop, resulting in the failure. After replacing the wire feeding hose and insulating the equipment, the equipment failure was eliminated.

(2) Alarm occurs when the ROBOT program of FANUCM -- 10I arc welding performs position searching, and the alarm number is: THSR-022 workpiece has no zero calibration.

Considering that this welding procedure is the first time for demonstration and trial operation, it should be related to programming parameters. Check the requirements of alarm countermeasures to adjust parts; In addition, since the alarm number is THSR, it is considered to check the parameters related to touch. DATA -- Touch the setting, then find the parameter number used for bit seeking and change the value of the origin position to open, then conduct bit seeking instruction for this position again, finally close the origin, and no alarm occurs in the trial run program.

3. External emergency stop line failure

External emergency stop line fault, the alarm number of this kind of fault is generally related to SRVO, but the main reason is that the emergency stop line is triggered and the equipment fault is caused. Therefore, this kind of fault is to check the Settings, hardware and lines related to the emergency stop of the equipment. The following is illustrated with two examples.

(1)FANUCM -- 10I arc welding robot is equipped with R-30IB controller to display alarm SRVO-232 NTED input, and the equipment cannot operate.

First, the alarm was reset. It was found that the alarm could not be reset. The reason for checking the fault code was that NTED(non-teaching enabling device) was detected. The fault countermeasures are: press NTED(non-teaching enabled device), and then press REST(Reset).

According to the fault countermeasures, no fault was found in the external emergency stop, because the emergency stop unit circuit board was replaced during the early maintenance of the equipment. During the inspection of the circuit board, it was found that the circuit board lacked a short plug CRMA96. After the short plug was connected to the circuit board A20B-2102-005, the equipment returned to normal.

(2)FANUCM -- 10I arc welding robot gives an alarm after replacing the emergency stop circuit board. The alarm number is: SRVO-372 OPEMG1 in abnormal state and SRVO-230 Chain in abnormal state.

The fault cause of checking the alarm number is: link alarm is detected through the emergency stop switch of the operation panel. Test the emergency stop switch is no abnormalities are found, check the emergency stop 24 v voltage is normal, check the bus conversion unit input signals found a emergency stop signal, check the line find fault, intermediate relay replacement cannot be reset after SRVO - 230 alarm, by manipulating the MENUS, ALARMS, F4 RES_CH1 - F4 is, REST, the alarm can be eliminated, eliminate equipment after returning to normal.

4. Equipment failure caused by long-term idling or maintenance of the equipment

If the equipment is idle for a long time or has been repaired, the fault code of such equipment is irregular. Generally, the equipment cannot operate due to improper parameter setting or the state change of the hardware and software of the equipment, and such fault should be repaired according to the previous maintenance content. The following is illustrated with two examples.

(1) When the FANUCM -- 10I arc welding robot is idle for A period of time, the zero point is lost due to the power cut and the encoder battery is replaced. During the zero point correction, an alarm occurs in the fifth axis of the robot, the alarm number is SRVO-050 collision detection alarm (G∶1 A∶5), and the alarm cannot be reset.

The main reason for the alarm failure is: (1) welding gun and workpiece impact. (2) Acceleration and deceleration are too severe. Fault of servo motor and servo amplifier. The servo motor brake failure. Servo motor power supply voltage, power line fault. 6. Reducer failure.

Check the fifth axis for the reason of failure. First, check all electrical lines. No abnormal power supply voltage is found. Then the servo motor and reducer are checked, and the worm and gear disk of the reducer are found to have collision marks. In order to further determine the cause of the fault, the servo motor is replaced. It is found that the equipment still gives an alarm and the reducer is found to have a fault.

Dismantling machine of decelerate of retarding mechanism found in counterclockwise direction runs smoothly, the runtime in the clockwise direction is dead center, takes a lot of force can pass, which can lead to alarm servo motor current is too high, further disassemble the parts found worm and gear disk gap need to be adjusted, through making adjustment gasket to adjust the clearance, final adjustment gaskets from 0.5 mm to 0.9 mm, eliminate dead point reducer running smoothly. After installing and correcting the origin, the equipment runs normally.