Scope of this guide
Management version: this defect as cost and risk — the metrics, audit points and claim defence.
This series answers a top recurring question from finishing forums with platingclub line practice. Parameters are industry-standard starting ranges — confirm against your supplier TDS.
Triage: symptom → confirm → first move
| Observation | Likely cause | Confirm by | First move |
|---|---|---|---|
| Thickness below spec on time | Dose under-counted | Amp-min per kg log | Recalculate by weight, not barrel count |
| Outer parts thicker | Normal barrel gradient | Sample by position | Extend cycle; sample per spec points |
| Cycle drifting longer | Contact resistance rising | Dangler tips check | Clean/replace danglers |
| Burns after time extension | CD ceiling reached | Burn map by position | Split load or lower current |
| Thickness scatter widens | Load size variance | Weigh-in records | Standardise load weight |
Cost, metrics and defence
| Cost line | Driver | Metric | Lever |
|---|---|---|---|
| Energy per kg | Longer cycles to 'be safe' | Amp-min per kg vs spec | Dose curve per family |
| Throughput | Over-length cycles | kg/hour by family | Publish thickness curves |
| Consumables | Media and danglers | Contact failure count | Daily dressing routine |
| Claims | Under-thickness escapes | Thickness audit failure rate | Sample plan discipline |
Engineer notes
- One variable per corrective action; verify by the confirm-by column.
- Records beat memory: log every trial on the tank card.
- Escalate when two consecutive actions fail — that is a senior call.
Safety: barrels, hoists and live bus bars share one line. Heat gloves for loads, lock-out before contact service, and never reach into a running barrel.
FAQ
Why are we over-cycling?
Fear and missing curves: without per-family data, planners pad time. Curves pay back in a month.
Which number tracks plating cost best?
Amp-min per kg against spec thickness — energy and chemicals both follow it.
How do we stop under-thickness claims?
Sample plan discipline and audit failure rate trend, published weekly.