Positioning Errors: Where They Come From
Common causes
| Source | Typical symptom |
|---|---|
| Fixture wear | Drift that grows over weeks |
| Thermal growth | Errors that change across the shift |
| Frame error | Errors after a fixture or program change |
| Tooling flex | Error proportional to force |
| Calibration | Consistent offset in one direction |
| Backlash | Repeatable pattern after a direction change |
Diagnosing it
- Measure the same point repeatedly at different times of day.
- Change one variable at a time.
- Record the offset, not just pass or fail.
Persistent positioning errors need measurement on site. This article lists common causes, not a diagnosis.