Guide to Fault Diagnosis and Maintenance of Servo Systems in CNC Lathes

Guide to Fault Diagnosis and Maintenance of Servo Systems in CNC Lathes

I. Fault Phenomenon and Cause Analysis

Motor fault ‌

Phenomenon ‌ : Abnormal movement of the machine tool (such as jamming, shaking) or alarm (such as alarm No. 6016).

Cause ‌ : power line short circuit, servo unit overload or abnormal input voltage of the driver.

Handling ‌ : Check the power cord connection (loose plug or damaged cable), and replace the air switch.

Servo control unit failure ‌

Phenomenon ‌ : The system issues an out-of-tolerance alarm or an alarm for an excessively high command value.

Cause ‌ : Abnormal input signal of the control unit or failure to send the drive signal.

Processing ‌ : Measure the input signal, confirm whether the command signal has been received, and replace the servo unit.

Drive system failure ‌

Phenomenon ‌ : The system does not respond at startup (such as 424 alarm).

Cause ‌ : Insufficient low-speed driving capacity of the drive module or increased mechanical resistance.

Process ‌ : Adjust the speed back to the reference point (such as the PRM534 parameter).

Ⅱ. Common Fault Handling Procedures

Check the power supply and connection ‌

Confirm that the 24V power supply is normal and check the closure of the NCON signal.

Check the connection of the power cord of the servo motor (poor contact of the plug or damaged cable).

Diagnostic control unit ‌

Enter the self-diagnosis mode (such as the SYSTEM key) and check the parameters (for example, the 6th digit of parameter 0200 shows "1").

Measure the input signal of the servo unit to confirm whether the drive signal is emitted.

Deal with mechanical problems ‌

Clean the encoder disk or replace it with a new encoder (encoder failure).

Adjust the installation gap of the grating ruler or clean the reading head (grating ruler malfunction).

Ⅲ. Preventive Maintenance Suggestions

Regularly check ‌

Regularly check the power cord and connection plug to ensure they are not loose or damaged.

Clean the encoder and the grating ruler reading head.

Environmental control ‌

Avoid working in harsh environments (such as high temperatures and humidity).

Replace the air switch regularly to ensure power stability.

Parameter calibration ‌

Regularly calibrate the feedback resolution and signal polarity parameters.

Adjust the speed back to the reference point (such as the PRM534 parameter).