A Kitamura HX250 equipped with a Yasnac i80M and Varispeed-626VM3 drive can experience a tool-change interference when the spindle stops with its drive pins misaligned to the tool-change arm keys. Parameter C2-1 is identified in the available drive manual as defining spindle origin, but the reported value could be edited only temporarily and could not be retained after power removal. The evidence does not identify the write-protection release method.
Separate the symptom from the root cause
The confirmed symptom is incorrect spindle orientation at tool extraction. A shifted encoder, an encoder-belt problem, or mechanical displacement following a crash are possible causes, but none is confirmed. Do not treat drive parameter write protection as proof that C2-1 is the correct adjustment point; the available guidance states that this alignment is performed in the control rather than the drive.
| Observation | Engineering decision |
|---|---|
| C2-1 changes but is not retained | Do not rely on the unrecorded value as a repair. |
| Encoder mount has moved | Restore mechanical encoder alignment before changing configuration. |
| Encoder belt is loose, damaged, or displaced | Correct the belt condition and then recheck orientation. |
| Evidence of a crash or displaced hardware | Restore the mechanical relationship before recalibrating origin. |
Inspect the orientation feedback path
Check the encoder mounting, encoder belt, and spindle drive train for movement or damage. Establish whether orientation is measured at the motor encoder and whether the spindle is belt driven; that architecture determines whether encoder rotation or belt position changes the spindle-to-feedback relationship. The supplied evidence does not confirm the feedback architecture of this specific machine.
Correct the alignment in a controlled sequence
- Secure the machine against unintended motion and move the tool-change mechanism to a condition where the arm, keys, and spindle pins can be inspected without interference.
- Inspect for a loose encoder mount, an encoder-belt fault, or displaced components consistent with a crash.
- Check the Yasnac control configuration or alignment procedure before attempting to defeat Varispeed write protection, because the available guidance places the alignment in the control.
- If the encoder mount is accessible and confirmed to be the displaced reference, loosen it, rotate it only enough to align the tool fingers, and retighten it. Treat this as a mechanical workaround until the original cause is established.
- If orientation is measured at the motor encoder and the spindle is belt driven, belt indexing affects the relationship. Repositioning the belt was suggested in the evidence, but perform it only after confirming that architecture and documenting the original position.
Verify before returning the machine to service
Recheck pin-to-key alignment at the extraction position before permitting an automatic tool change. Then observe the orientation repeatedly without allowing the arm to contact the spindle keys. A successful check requires repeatable alignment and no interference; continued drift indicates that the feedback or mechanical drive problem remains unresolved.
FAQ
Why will Varispeed-626VM3 parameter C2-1 not save?
The reported drive allowed C2-1 to be changed but did not retain it after power removal, indicating active write protection. The evidence does not provide the unlocking procedure, so verify whether spindle-origin alignment belongs in the Yasnac control before pursuing drive access.
What causes spindle pins to miss the tool-change arm keys?
Supported possibilities include a shifted encoder mount, an encoder-belt problem, or mechanical displacement after a crash. Inspect those relationships before changing the spindle-origin setting.
Can I rotate the spindle encoder to restore tool-change alignment?
Rotating and retightening the encoder mount is a documented workaround when the mount is accessible and its position controls orientation. Confirm the feedback architecture, preserve the original position, and verify repeated interference-free alignment afterward.