How to determine if a CNC lathe has a mechanical fault?

Step 1: Initial Matching of Fault Symptoms with Characteristics

Mechanical faults typically exhibit external manifestations, which can be checked against the following:

1. Obvious Physical Abnormalities: Such as loose or displaced parts, oil leaks, abnormal noises, abnormal heating, or sluggish/jammed movements. These are most likely caused by wear or damage to mechanical parts.

2. Gradual Decrease in Machining Accuracy: For example, slowly deviating from the machining dimensions or gradually increasing surface roughness. This is generally due to long-term wear leading to increased spindle/leadscrew backlash, which is a mechanical fault. Sudden accuracy abnormalities are more likely to be electrical parameter issues.

3. Abnormal Motion: Intermittent crawling feed, or tool change actions getting stuck halfway through. These phenomena, related to mechanical friction and transmission clearance, are also often mechanical faults.

Step Two: Final Confirmation Through Isolation Testing

If the phenomenon is atypical, simple tests can be used to differentiate:

1. Manual Power-Off Test: After disconnecting the power, manually rotate the spindle and move the worktable. If uneven resistance, jamming, or abnormal noises are felt during manual movement, it can be basically determined that the problem is a mechanical component jamming or damage. If manual movement is smooth and the fault only occurs during automatic operation, it is most likely an electrical or system problem.

2. Functional Decomposition Verification: For example, if the spindle does not rotate, first test the spindle motor separately. If the motor can rotate normally and output power, it indicates that the fault lies in the mechanical transmission part (broken transmission belt, stuck coupling). If the motor itself does not rotate, it is an electrical fault.

3. Parameter Cross-Verification: Back up the original parameters and restore the factory default parameters. If the fault still exists, the parameter setting problem has been ruled out, and it can be determined that it is a physical mechanical fault. If the fault disappears after restoring the parameters, it indicates that it is a system parameter problem rather than a mechanical fault.