Diameter tolerance and consistency affect flow, wall width, pressure and fit. Measure the average, spread and ovality across the spool, not only the nominal value.
Measure correctly
- Calibrated gauge or laser.
- Several points and directions.
- Start, middle and end.
Use the data
Recalibrate flow after changing lot or supplier. Inspect ovality and slow drift because both can change extrusion without an obvious visual defect.
Set acceptance
- Minimum and maximum.
- Sampling plan.
- Record by lot.
| Indicator | Effect | Control |
|---|---|---|
| Average | Flow | Calibration |
| Spread | Wall width | Limit |
| Ovality | Layer shape | Measurement |
| Drift | Stability | Trend |
Common engineering mistakes
- Using one measurement.
- Ignoring ovality.
- Changing spool without calibration.
- No acceptance limit.
- Losing batch records.
Buyer checklist
- Is the gauge calibrated?
- Are multiple points measured?
- Is the spread known?
- Is flow recalibrated?
- Is the limit documented?
Request dimensional data through our quote form.