Washing machine drum run-out test
While the drum turns at constant speed, a laser displacement sensor measures its axial run-out without contact. The peak-to-peak value is compared with the limit band and each bay shows its trace.
The run-out trace and the peak-to-peak value are written to the test record with the serial number; a machine above the limit is flagged on the stack light and the bay monitor and routed to the repair line.
- 01 Position
- 02 Spin-up
- 03 Measure
- 04 Decide
The sensor carriage moves in front of the next test bay.
- Run-out (p-p)
- —
- Drum speed
- —
Scenes are illustrative simulations; they are not customer references or performance guarantees.
Need
Run-out is in the millimetre range and must be measured while the drum turns. The perforated, shiny stainless sheet rules out a contact probe, and holes and reflections cause spikes in a laser reading. The machine sits a little differently in the bay each time; bay vibration adds to the signal.
Solution approach
A laser displacement sensor rides a linear axis to the next bay and aims through the door opening at an off-axis point on the drum's rear wall. At test speed, axial position is sampled in sync with rotation angle and outliers are filtered. Peak-to-peak run-out is independent of the mean, so the machine's seating in the bay does not affect the result. One sensor measures both bays in turn.
Process steps
- 01
Position
The sensor carriage moves in front of the next test bay.
- 02
Spin-up
The drum reaches test speed and the laser is aimed into it.
- 03
Measure
The axial position of the turning drum is sampled into a run-out trace.
- 04
Decide
Peak-to-peak run-out is compared with the limit band; the stack light shows the result.
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