Nine cases of failure maintenance of the hottest s

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9 cases of spindle drive system fault maintenance (I)

case 1 Fault maintenance of flow detection switch

fault phenomenon: a CNC grinder equipped with Siemens SINUMERIK 810 system has a fault alarm "f31 spindle cooling circuit", indicating that there is a problem with the spindle cooling system

analysis and treatment process: check that there is no problem with the cooling system. Refer to the PLC ladder diagram. This fault is detected by the flow detection switch b9.6. Check the switch and find that it is damaged. Due to the switch problem, the alarm error is caused; Replace the switch with a new one, and the fault disappears

case 2 Fault maintenance of unstable hydraulic pressure

fault phenomenon: a special CNC milling machine breaks down during the batch processing of parts. Each fault occurs when the parts have been processed and the z-axis has not been moved back in place. When the processing program is interrupted, the spindle stops rotating, and the f97 alarm spindles peed not OK station 2 is displayed, indicating that there is a problem with the spindle

analysis and processing: check the spindle system and there is no problem. Other problems can also cause the spindle to stop rotating, so the external programmer is used to monitor the operation state of the PLC ladder diagram. It is found that the tool hydraulic clamping pressure detection switch f21.1 is instantly disconnected in case of failure. Its disconnection indicates that the clamping force of the milling cutter is not enough. For safety reasons, the PLC stops the spindle. The hydraulic pressure is found to be unstable after inspection; After adjusting the pressure of the hydraulic system to make it stable, the fault is eliminated

example 3 Fault maintenance of spindle tool alarm

fault phenomenon: a supporting Okuma osp700 system, model xhad765 CNC machine tool, has an abnormal alarm of spindle tool detection, and the system is in an emergency stop state

analysis and treatment process: this fault is mostly due to the artificial insertion of tools into the spindle when the system believes that the spindle has no tools; Or when the system thinks that the spindle has a knife, it takes off the spindle knife manually and changes the operation mode. The spindle sensors sql0, sqll and SQL2 are less likely to fail. As long as the mode is switched back to zero mode, after reset and start, remove or insert the tool in the spindle, and keep the actual state consistent with the spindle tool state in the system

if the fault is not caused by the above human factors, open the PLC data or ladder diagram to check whether the above three switch signals isptcl, isptl and isptul can be received normally, and then check whether the switch has fault

according to the above inspection, it is found that the oil inlet contact of the sqll switch plug is poor, and it is normal after treatment

example 4 Troubleshooting of spindle stop during machining

fault phenomenon: a CNC machine tool equipped with FANUC OMC system and model XH754 suddenly stops rotating during boring processing, while z-axis feeding continues, and the machine tool does not have any alarm, resulting in tool and workpiece damage

analysis and treatment process: this fault is strange and difficult to determine at the moment. In order to confirm the fault, the workpiece is removed and the machine tool is left idle. The probability of this fault is different. Sometimes there is no fault for a long time, and sometimes it occurs in succession. To determine whether it is caused by interference, stop other machine tools and reprocess the grounding. The fault still exists. Then, starting with the signals related to the spindle control, the tepex surface layer can significantly improve the stiffness of the PMC input and the status of the relevant registers in the ladder diagram. During the inspection, it was found that when the fault occurred, the PMC CNC signal g120.6 (spindle stop) was high, and the spindle stop command was not sent to the CNC (g120.6 was low, spindle stop); When checking g229.4 and g229.5 related to spindle rotation again, it is found that g229.4 is highlighted when it is normal, the spindle rotates forward, and g229.4 is off when the fault occurs

when the spindle maintains positive rotation, r728.4 passes through x04.5 normally closed r705.1, r728.4 normally open, x016.7 normally open, r728.0 normally closed, r728.5 normally closed, x016.1 normally open, x016.2 normally closed to maintain continuity (highlighted) and then g229.4 to maintain g229.4 conductivity 5: regularly check the screw connection at the jaw, and the positive rotation will stop as long as one of these contacts is disconnected: during continuous observation, it is found that the brief flashing of x016.1 causes r728.4 to disconnect, so it is suspected that there is a problem with x016.1. X016.1 is the detection signal of spindle tool clamping in place. The corresponding travel switch SQL2 was removed and opened for inspection. It was found that its spring plate was almost completely broken. After replacement, restart the machine for inspection. "The customer commented that the lap shear strength (23 ℃) did not fail again

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