FANUC α i Series Servo and Spindle System Maintenance Guide

FANUC α i Series Servo and Spindle System Maintenance Guide

FANUC α i series servo motors, spindle motors, and servo amplifiers are the core driving components of modern CNC machine tools, and their stable operation directly affects machining accuracy and production efficiency. It is crucial to follow standardized maintenance procedures to ensure the long-term reliable operation of equipment and prevent unexpected shutdowns. This guide integrates the key content of FANUC's official maintenance manual (B-65285EN/04) to provide detailed and professional maintenance guidance for engineers and technicians, covering safety warnings, daily inspections, fault diagnosis, and component replacement procedures.

Safety Warning and Precautions

Before operating any FANUC device, it is necessary to fully understand and comply with the safety classification in the manual:

Warning: Indicates a risk of personal injury or serious equipment damage. For example, after the servo motor is powered off, the internal capacitor may still have high voltage. Before making contact, it is necessary to wait for at least 5 minutes and confirm that the charging indicator light is off; Absolute encoder battery replacement must be carried out with the power on, otherwise position data will be lost; Do not touch the running motor or radiator with your hands to prevent burns.

Attention: Indicates possible equipment damage. For example, motors or amplifiers cannot be disassembled as improper disassembly can lead to malfunctions; Insulation testing can only be carried out using a 500V megohmmeter and according to the specified method, otherwise the winding may be damaged.

Note: Provide supplementary information to assist in understanding and operation.

Preventive maintenance of motors

The motor is the executing unit for electromechanical energy conversion, and its health directly affects its motion performance. The maintenance focus includes:

Appearance and connection inspection: Regularly inspect the motor housing for cracks, deformation, or oil stains; Whether the cable sheath is damaged or aged; Whether the connector is locked and whether there is any corrosive liquid intrusion.

Running status monitoring: Monitor for abnormal noise or vibration during operation. If there is periodic abnormal noise, it may indicate bearing wear; If the vibration changes with the speed, it is necessary to check the tension of the coupling or belt.

Electrical parameter measurement:

Winding resistance: Disconnect the motor from the amplifier, use a multimeter to measure the phase to phase resistance, and compare it with the nominal value in the manual. If the deviation is too large, it indicates that the winding may be short circuited or open circuited.

Insulation resistance: Use a 500V megohmmeter to measure the insulation resistance of the winding to ground (casing). The new motor or long-term storage should be greater than 100M Ω; if it is lower than 1M Ω, the motor must be replaced. Before measurement, ensure that the motor is dry and cooled to room temperature.

Cooling fan maintenance: For motors with fan cooling, it is necessary to regularly clean the chips and oil stains on the fan cover and check whether the fan runs smoothly. If the fan stops running or produces abnormal noise, the fan unit should be replaced. Pay attention to the rotation direction of the fan blades and the polarity of the connector when replacing.

Special motor precautions: For built-in spindle motors or linear motors, which contain strong magnets inside, special attention should be paid to keeping them away from medical equipment such as pacemakers during maintenance, and it is forbidden to operate them under external power drive to avoid danger caused by power generation.

Maintenance of servo amplifier

The servo amplifier (including power module, servo module, and spindle module) is the core of drive control, and its maintenance focuses on heat dissipation, electrical connections, and internal energy storage components.

Environment and Installation: The amplifier should be installed in a clean, dry, and well ventilated electrical cabinet, with an ambient temperature not exceeding 55 ℃. Ensure that the cooling air duct is unobstructed and regularly clean the dust on the cooling fins. The cabinet door should be equipped with a filter and replaced regularly.

Interpretation of status indicator lights:

Power module (PS): LED display "-" indicates that the main circuit is not powered on (emergency stop state); '00' indicates readiness; Numerical or letter codes indicate alarms or warnings, such as "01" for IPM faults and "07" for DC bus overvoltage.

Servo module (SV): LED display "-" indicates waiting ready; '0' indicates excitation ready; Numbers such as "1" indicate internal fan failure, "2" indicate control power undervoltage, and "8", "9", and "A" indicate IPM alarm or overcurrent.

Spindle module (SP): After power on, it briefly displays the software serial number and version, and then flashes "--" to indicate waiting for communication; '00' indicates excitation; Alarm codes such as "01" indicate motor overheating, "02" indicates excessive speed deviation, and "12" indicates DC bus overcurrent.