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Mighty Way Industrial Limited

Why Are Fatigue Life Predictions for PA66-GF25 Cages Unreliable, and What Alternatives Exist?

July 09,2026

1. Strict temperature limit: -30°C to +110°C (short‑term 120°C).

2. Hygroscopic – dimensional changes (0.2-0.5% size increase per 1% moisture uptake) may cause interference.

3. Not for vacuum (outgassing) or strong acids/alkalis.

4. No widely accepted fatigue life model; moisture absorption and ageing make calculations unreliable.

5. Centrifugal deformation can be estimated, but creep cannot be quantified.

6. Speed/temperature can only be assessed using material limits - precise life prediction not possible.

7. Life: the cage is often the “weakest link” – schedule first inspection at 30-50% of calculated bearing life.

8. Field judgement: if cage crumbles or melting smell appears, stop immediately.

9. Empirical life: under rated conditions, usually no more than 15,000 hours - mandatory replacement.