Application of FANUC system parameters in machine tool maintenance

The FANUC system has a rich set of machine tool parameters, which brings convenience to the installation, debugging and daily maintenance of CNC machine tools. Based on years of practice, the application of commonly used machine tool parameters in maintenance is introduced.

1. The hand pulse generator is damaged. On a FANUC 0TD CNC lathe, the hand pulse generator failed, making it impossible to fine-tune the tool, and the faulty part needed to be replaced or repaired. If there are no suitable spare parts at that time, you can set parameter 900#3 to “0” first, temporarily disable the manual pulse generator, and use the inching button single pulse generator operation for tool fine-tuning. Set this parameter to “1” after the manual pulse generator is repaired.

2. When the machine tool is turned on and returns to the reference point, an overtravel alarm occurs. When the above machine tool returns to the reference point, a 510 or 511 overtravel alarm occurs. There are two processing methods:

(1) If a 510 or 511 overtravel alarm occurs during the X-axis return to the reference point, you can change the value of parameter 0700LT1X1 to +99999999 (or change the value of 0704LT1X2 to -99999999) before returning to the reference point again. If there is no problem, change the value of parameter 0700 or 0704 to the original value. (2) Press the P and CAN keys at the same time and turn on the machine to eliminate the overtravel alarm.

3. A FANUC 0i CNC lathe had an ALM701 alarm shortly after it was turned on. The maintenance manual explains that the fan in the upper part of the control unit is overheated. Open the electrical cabinet of the machine tool and check that the fan motor does not move. Check that the fan power supply is normal. It can be determined that the fan is damaged. Since the same type of fan cannot be purchased at the moment, the parameter RRM8901#0 must be set first. Change it to “1” first to release the ALM701 alarm, and then use forced cold air cooling. After the fan is purchased, change PRM8901 to “0”.

4. In a FANUC 0M CNC system machining center, during the tool change process of the spindle, a contact collision and abnormal noise occurred at the moment when the spindle came into contact with the tool change arm. The cause of the failure was analyzed to be due to inaccurate positioning of the spindle, resulting in poor fit between the spindle head and the tool changer arm, which would undoubtedly cause mechanical impact sounds, and there were obvious bruise marks in both places. After inspection, it was found that there was no mechanical looseness in the tool change arm and the spindle head, and the positioning movement of the tool change arm was accurate. Therefore, the problem was solved by modifying the N6577 parameter value, that is, after changing the original data 1525 to 1524, the fault was eliminated.

5. Confidential type parameters 0900~0939 maintenance method. When transmitting parameters according to the method in the FANUC 0MC operating instructions, the confidential parameters 0900~0939 must be input using MDI, which is very inconvenient. Now we introduce a transmission method that can transmit confidential parameters 0900~0939. The steps are as follows:

(1) Set the mode switch to the EDIT position;

(2) Press the PARAM key to select the screen displaying parameters;

(3) Set the external receiving device to STAND BY (ready) state;

(4) Press the EOB key first without releasing it, and then press the OUTPOT key to output all parameters.

6. For a FANUC 0MC vertical machining center, due to the failure of the absolute position encoding battery, the X, Y, and Z reference points were lost and the reference points had to be reset.

(1) Change PWE “0” to “1”, change parameter NO.76.1=1, and change NO.22 to 00000000. At this time, the CRT displays a “300” alarm, that is, the X, Y, and Z axes must return to the reference point manually.

(2) Turn off and on again, use the handwheel to move X and Y to the reference point position, and change parameter NO.22 to 00000011, which means that X and Y have established the reference point.

(3) Move the Z-axis to near the reference point, install a tool holder on the spindle, and then manually clamp the robot arm to fully clamp the tool holder. At this time, change parameter NO.22 to 00000111, which means the Z-axis establishes the reference point. Set NO76.1 to “00” and change PWE to 0.

(4) Turn the machine off and on again, and use G28 X0, Y0, Z0 to check the mechanical reference point.

7. No alarm fault caused by machine parameters. A FANUC 18i-W slow wire feeder. After powering on, the CRT displays inaccurate X, Y, U, and V coordinate axis positions. That is, it normally displays three digits after the decimal point, and the front displays four digits after the decimal point, and the CRT does not Alarm information. First of all, it should be suspected that parameter changes cause the above failure. After checking the parameters, it was found that NO.0000#2 INI has changed. It originally displayed “0” (indicating metric input) normally, but when there was a fault, it displayed “1” (imperial input). After changing this parameter to “0”, the digital display was normal.

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