The common problems and solutions of CNC Machining centers are as follows:

1. Sudden loss of parameters (0MD system)

Hello FANUC expert: Our company has a machining center that displays bar shaped garbled characters for 930AL and CRT during operation. After shutting down and restarting, all parameters were lost. Then, when the parameters were entered in the startup state, the machine can run normally. I wonder what is the reason for this? Thank you for your support and assistance!

Answer: The sudden loss of parameters may be related to the storage board, battery, or external interference. 930 also indicates that there may be external interference causing the CPU to malfunction and trigger a system alarm. It cannot be ruled out that there may be motherboard or other PCB faults.

2. 926 alarm (18i) Now another machining center has experienced a 926 alarm, and there is no display on the LCD of the control system except for the alarm information (at that time, the temperature inside the electrical control cabinet was high). I don't know why, I look forward to an answer. thank you!

Answer: The cause and handling of the 926 alarm (FSSB alarm) is that the FSSB (servo serial bus) connecting the CNC and servo amplifier has malfunctioned. If there is a problem with the FSSB, optical cable, and servo amplifier connected to the axis control card, this alarm will occur. Confirm the fault location using the LED on the servo amplifier. Can the 7-segment LED on the servo amplifier be used to confirm the location of the fault? If the power supply of a servo amplifier fails, an FSSB alarm will occur. Due to the voltage drop of the control power supply caused by the amplifier fault, or the+5V grounding of the encoder cable, or other reasons, a power failure may occur, resulting in an FSSB alarm. If the above measures diagnose a fault in the axis control card, replace the axis control card on the main CPU board.

3. Alarm (0imate-B) Recently, one of our company's lathes has been experiencing frequent alarms of 9209, 11930, with 930 being the most common. Please provide technical support, I would greatly appreciate it.

Answer: 911SRAMPARITY: (BYTE1) Parity error occurred in some program storage RAM. Clear all RAM, or replace SRAM module or motherboard. Then reset the parameters and data. 920SERVOALARM (1-4AXIS) This is the servo alarm (first to fourth axis). There has been a monitoring alarm or RAM parity error in the servo module. Please replace the servo control module 930CPUINTERRUPTCPU on the motherboard for abnormal interruption of alarm. The motherboard or CPU card is faulty. The faulty component can be confirmed by exchanging parts, and attention must also be paid to machine grounding and external interference

4. Parameter cannot be rewritten (BJ-FANUCOi MB) Hello, our company has a new machine produced in Taiwan. After installing the new machine and testing it, we found that the B-axis cannot return to zero. When the B-axis is turned to the return to zero switch, it starts to slow down, but shortly after turning, there will be a No. 90 alarm, which cannot return to zero. I don't know what the reason is, please help solve it. thank you very much!

Answer: Alarm Explanation No. 90: When the condition of returning to the reference point at a speed equivalent to a positional deviation (DGN. 300) greater than 128 pulses in the direction of returning to the reference point is not met, and the CNC has received at least one 1-turn signal, this alarm occurs when returning to the reference point. Inspection: 1. Return to zero speed; 2. One turn signal.

5. After a period of inactivity, the machining center (FANUC-18iM) machine turned on and an alarm appeared: 701: OVERHEAT: FANROTOR. After investigation, it was found that the alarm was due to a malfunction in the CNC system cooling fan. However, after inspection, it was found that the fan was running normally and the alarm could not be eliminated. Finally, only by changing parameter # 0 of 8901 from "0" to "1" can the alarm be blocked. Hope it can help solve it, thank you!

Answer: The fan is broken, but it can still rotate, so we can only purchase a new one for replacement.

6. The machine tool alarm (FANUC-18) is triggered after the spindle is overloaded, with alarm number 751. The spindle servo module alarm number AL-73. How can it be repaired?

Answer: The motor sensor signal is disconnected. (1) The situation where an alarm occurs when the motor excitation is turned off (a) is due to incorrect parameter settings. Confirm the sensor settings parameters. (b) Please replace the cable if it is broken. (c) Sensor adjustment fault, please adjust the sensor signal. When unable to adjust or signal observation is not possible, please replace the connecting cable and sensor. (d) SPM malfunction, please replace SPM or SPM control printed circuit board. (2) When the cable is triggered (such as during spindle operation), an alarm may occur due to wire breakage. Please replace the cable. When cutting oil invades the connector part, please clean it. (3) In case of an alarm during motor rotation, (a) Confirm the cable shielding fault between the sensor and SPM. (b) If the cable from the sensor to SPM is tied together with the power line of the servo motor, please tie them separately.

7. 351 alarm (Oi-M) - One machining center, OI-M system, NC control X, Y, Z, B4 axis, B axis is the rotation axis. Fault phenomenon: During processing, a 351 alarm occurred, all at the N5H6Z344.2 program segment, but there was no B-axis work instruction in this segment. After the malfunction, all 4-axis modules display a "-". After powering on again, it worked normally, but after a period of operation, this fault occurred again. There are currently an average of 2-3 occurrences per class. Solution: Diagnosis screen 0203 # 5 # 6 shows 1, and the fault range is 1: poor connection of signal cable; 2. Poor hardware of encoder, motherboard, and servo module. Because restarting can temporarily eliminate the fault, it can eliminate 1. Regarding 2, we re plugged the plugs of the encoder, motherboard, and servo module, but there was no effect. The fault still exists. Could you please analyze what we should do next?

Answer: Mainly check from one point, which is related to the signal cable. Check the signal cable of the alarm axis to see when it has moved (often in other axis moving types, where the cable of this axis is dragged). If the cable is folded back and forth for a long time, it will have poor contact and alarms will occur irregularly. At this point, we can only replace the cable with a new one.

8. What are the reasons for the simultaneous alarm processing of 408 # and 409 # on the FANUC0MD machine tool? Could you please advise?

Answer: It is generally unlikely for both 408409 alarms to occur simultaneously. 408 is communication failure, which means that there is no communication between the spindle amplifier and the system (storage board). Usually, if the spindle amplifier has no power or the interface is damaged, the 409 alarm will sound, indicating that the spindle amplifier has an alarm number. The specific alarm number is displayed on the amplifier.

9. After the fan (0i mate TB) system triggered an alarm with the number "6119113", it was found that the cooling fin fan of the power module did not rotate. After replacing it with another normally running fan, it worked normally. Confirmed that the fan is broken. After purchasing the same type of fan and replacing it, the above alarm still appears (the fan is running normally). After inspection, it was found that although this fan is produced by the same manufacturer, the current is 0.03A higher than the original 0.1A. After swapping it with the fan on the spindle drive module, the "6119113" alarm no longer appears, but the "FAN" flashes on the CRT, which does not affect processing. Is it true that the detection of fans does not rely on sensing components such as thermistors, but only on the detection of current magnitude? Answer: It is best to purchase a fan of the same model. If the "FAN" flashes on the CRT, it is because there is an external fan problem on the cooling fin of the spindle drive module

11. What does the alarm of 506507 in the FS21T system indicate? Our company's FS21T system's CNC lathe alarms when it starts up. What does the alarm of 506507 in the FS21T system indicate and how can it be resolved?

Answer: 506OVERTRAVEL:+nExceeded through axis+sidehardware OT. 507OVERTRAVEL: - nExceed through axis sidehardware OT. Does hardware overtravel occur simultaneously?

12. Position display (FANUC-0M) malfunction, position display changes from three decimal places to four decimal places?

Answer: Parameter modification: Change No.0001 # 0SCW1 to 0.