Maintenance & Troubleshooting of CNC Robots Flashcards
7 cards from real FANUC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Maintenance & Troubleshooting of CNC Robots flashcards as text
A FANUC robot displays alarm code SRVO-023 (Stop Error Excess). What is the most likely cause?
Answer: The robot reached a position error exceeding the defined threshold during motion
SRVO-023 indicates the positional deviation between commanded and actual position exceeded the stop error limit, typically caused by mechanical binding or incorrect gain settings.
When replacing a FANUC pulse coder (encoder), which step must be performed immediately after installation?
Answer: Perform a mastering (zero-point calibration) procedure
A new pulse coder loses the stored zero-point data, so mastering must be performed to re-establish the robot's reference position.
Which FANUC diagnostic screen shows real-time axis torque values useful for detecting mechanical overloads?
Answer: Status/Servo screen (servo diagnostic monitor)
The Servo diagnostic monitor (Status > Servo) displays real-time torque percentage, current draw, and positional error for each axis.
A FANUC CNC robot exhibits excessive backlash on Joint 2. After ruling out software causes, what mechanical component should be inspected first?
Answer: The harmonic drive reducer or gearbox
Excessive backlash on a robot joint is most commonly caused by wear or damage in the harmonic drive reducer or gearbox that transmits motor torque to the link.
What does the FANUC controller variable $SCR_GRP[1].$SOFTLMT indicate?
Answer: The software joint travel limit boundaries for group 1
$SCR_GRP[1].$SOFTLMT contains the software over-travel limit values that the controller checks against joint angles to prevent exceeding the defined workspace.
During preventive maintenance, the recommended method to check FANUC robot grease condition in joint reducers is to:
Answer: Inspect grease color and quantity at the drain port during scheduled interval
FANUC maintenance schedules require draining and inspecting grease at defined intervals (typically 3,840 operating hours) by checking the drain port for color, contamination, and correct quantity.
A FANUC robot arm drifts out of position overnight with the controller powered off. What is the most likely cause?
Answer: Worn or failed axis brake not holding joint position
If a robot axis drifts when power is removed, the electromagnetic brake for that joint is failing to engage and hold, requiring brake inspection or replacement.