Practical Guide to Fault Diagnosis of numerical control lathe

　　The fault diagnosis of numerical control lathe follows the core logic of"first phenomenon,then essence,first easy,then difficult,and first external,then internal".Through the four step process of"symptom observation preliminary investigation precise positioning fault elimination",common mechanical,electrical,and system faults are quickly solved to ensure production continuity.The specific practical methods are as follows:

　　Step 1:Symptom observation and information collection

　　-Record the specific manifestations of the fault,including alarm codes,shutdown status,abnormal motion(such as jamming,shaking),machining accuracy deviation(size deviation,surface roughness),etc.,and clarify the timing of the fault occurrence(appearing immediately upon startup or during machining).

　　-Collect background information of the equipment,check the running time,recent maintenance records,whether there has been a power outage/collision/parameter modification,ask the operator about the pre fault operation process,and provide clues for troubleshooting.

　　-By utilizing the self checking function of the equipment,system logs and PLC status can be viewed through the control panel,and fault feedback from servo drives and spindle amplifiers can be read to preliminarily determine the type of fault(mechanical/electrical/system).

　　Step 2:Preliminary investigation(quickly eliminate basic problems)

　　-Check the power supply and gas source,confirm that the power supply voltage is stable(fluctuation≤±5%),the air switch is not tripped,and the gas source pressure meets the standard(usually 0.4-0.6MPa),clean the pneumatic component filter,and eliminate faults caused by abnormal power and gas supply.

　　-Verify the parameter settings,compare the system parameters,tool compensation parameters,and coordinate system parameters before and after the fault.If there are any erroneous changes,restore the default values or backup parameters to avoid operational abnormalities caused by parameter confusion.

　　-Check external connections and environment,inspect cable joints for looseness or damage,check cooling and lubrication systems for oil/water leakage,clean dust and impurities from guide rails and screws,and avoid poor contact or jamming caused by external factors.

　　Step 3:Precise positioning(troubleshooting by fault type classification)

　　Mechanical faults(lagging,accuracy deviation,abnormal noise)

　　-Transmission system:Check the lubrication and wear of the ball screw and guide rail.If there is abnormal noise or high resistance to movement,special lubricating grease should be added.If the wear is severe,replace the screw or guide rail slider.

　　-Spindle components:Abnormal noise from spindle rotation may be caused by bearing damage.Measure the spindle runout and replace the bearing if it exceeds the tolerance;If the spindle speed is unstable,it is necessary to check the belt tension or the variable frequency speed regulation module.

　　-Fixtures and cutting tools:The positioning accuracy deviation of the fixture needs to be recalibrated,and the jaws should be replaced in a timely manner if they are worn out;Tool wear and chipping can lead to poor machining accuracy,requiring re sharpening or tool replacement.

　　Electrical faults(alarm,no action,abnormal signal)

　　-Servo system:The alarm of the servo drive needs to be interpreted according to the manual.Common faults include overload(check if the load is too large)and encoder failure(clean the encoder dust or replace it).

　　-Control circuit:If the input and output signals of the PLC are abnormal,use a multimeter to detect the contacts of the relay and contactor.If they are burned,replace them;Button and travel switch malfunction should be tested for continuity,and any damage should be replaced promptly.

　　-Motor malfunction:The servo motor and spindle motor are overheating or not rotating.Measure the winding resistance to determine if they are burnt out,and check if the motor wiring terminals are oxidized or loose.

　　System malfunctions(crashes,abnormal program execution)

　　-Program issue:If the program reports an error,check for syntax errors,coordinate overtravel,modify the program,or adjust the processing range;Program loss can be restored through backup,while checking if the storage medium is damaged.

　　-System crash:Even after restarting the numerical control lathe,it still cannot operate normally.It is necessary to contact the manufacturer for system reinstallation or firmware upgrade to avoid data loss caused by self operation.

　　Step 4:Troubleshooting and Verification

　　-After targeted troubleshooting,conduct a no-load trial run to check if the equipment moves smoothly and if the parameters are normal.If there are no abnormalities,proceed with trial cutting and processing.

　　-Verify whether the fault has been completely eliminated through the dimensional accuracy and surface quality of the test cut piece,and record the cause and handling process of the fault to form a fault file,which facilitates the rapid resolution of similar problems in the future.

　　In practical use,it is necessary to avoid blindly disassembling core components and prioritize using the built-in diagnostic function and basic tools(multimeter,wrench,plug gauge)of the numerical control lathe for troubleshooting.For complex faults,it is recommended to contact professional technicians.