How to determine which part of a CNC lathe is faulty?

I. Preliminary Quick Troubleshooting Methods

1. Visual Inspection: This is the most basic first step, directly identifying the anomaly through observation, listening, questioning, and palpation: Inquire about the machining status and symptoms at the time of the fault; check CRT alarm messages and indicator lights for deformed or burnt components, or tripped protectors; listen for abnormal sounds; smell for burnt electrical components; feel for abnormal heat or vibration. This method can quickly identify obvious faults such as oil leaks, loose wiring, and burnt components.

2. Self-Diagnostic Function Method: Utilizing the self-diagnostic system built into the CNC lathe, the system module to which the fault belongs can be initially located based on the alarm codes displayed on the screen, narrowing down the troubleshooting scope.

II. Precise Location Diagnosis Methods

1. Parameter Detection Method: CNC parameters are stored in memory. External interference and insufficient battery voltage can cause parameter loss or corruption, which is the root cause of many system faults. Checking and calibrating against standard parameters can quickly locate faults caused by abnormal parameters, especially suitable for lathes that malfunction upon startup after long periods of inactivity.

2. Replacement Comparison Method/Component Exchange Method: When it's difficult to determine if a suspected component is functioning correctly, compare the faulty machine tool with identical components from a working machine tool, or replace the suspected component with a functional component of the same model. If the fault disappears after replacement, the component is confirmed to be faulty; if the fault remains unchanged, it's unrelated to the component. Swapping identical functional modules can also pinpoint the fault location based on the direction of fault transfer.

3. Functional Testing Method: Manually write a small program containing the lathe's various functional instructions. Running the program tests the effectiveness of each function, allowing you to determine which functional module is missing. This method is suitable for situations where the fault symptoms are unclear.

4. Partial Stop Method/Isolation Method: For rotary system faults, intermittently stop or isolate the operation of a portion of the components and observe changes in the fault symptoms. For example, if there's abnormal noise from the headstock, sequentially connect each axis. When the sound matches the abnormal noise of the fault, the faulty axis can be identified, distinguishing between a fault in the CNC section, servo system, or mechanical part. 5. Trial and Error Method: For faults that can be caused by multiple factors (such as tool deflection), first make trial adjustments to the most likely cause, observe the changes in the fault to prove the fault location, and gradually eliminate possibilities until the root cause is found.

6. Monitoring and Measurement Method/Instrument Measurement and Diagnosis Method: Use tools and instruments such as multimeters, oscilloscopes, and pressure gauges to directly measure parameters such as voltage, current, signal waveforms, and hydraulic pressure at the fault location, and compare them with normal values ​​to identify the faulty component. For example, an unstable pressure gauge pointer in a hydraulic system can directly indicate a leak or air intake in the oil circuit.

7. Trial Cutting and Measurement Method: When machining accuracy is not up to standard, measure the parts after trial cutting, and use the measurement results to inversely determine the fault location: for example, use part vibration marks to determine machine tool vibration, use form and position errors to determine machine tool geometric accuracy problems, and use thread/gear machining errors to determine the accuracy of the rotating chain.

8. Principle Analysis Method: Starting from the working principle of CNC lathe, this method analyzes the parameters of each point in conjunction with the circuit control diagram. It requires a high level of professional competence from maintenance personnel and is suitable for in-depth location of complex circuit faults.