Scope of this guide
Management version: this defect as cost and risk — the metrics, audit points and claim defence.
Series: finishing.com recurring questions answered with platingclub line practice. Parameters are industry-standard starting ranges — confirm against your supplier TDS.
Triage: symptom → confirm → first move
| Symptom | Likely root | Confirm by | First move |
|---|---|---|---|
| Burnt, gray nodules on edges/high points | Local CD far above window | Position map vs rack layout | Cut total amps; add thieves |
| Bare spots in recesses while edges burn | Throwing power ceiling | Coverage vs position chart | Aux anode trial on recess |
| Burns after bath cools overnight | Temperature-CD coupling | Temp + amps log overlay | Interlock heat to line start |
| Burns only on new racks | Contact resistance low, current hogging | Contact check by rack age | Balance load across racks |
| Coverage loss with normal burn | Catalyst ratio drift | Hull cell + titration | Correct sulfate ratio 100:1 |
Cost, metrics and defence
| Cost line | Driver | Metric | Lever |
|---|---|---|---|
| Strip-and-replate hours | Chronic edge burns | FPY by defect family | Amp staging + thieves |
| Energy | Over-amped coverage chasing | kWh per good part | Geometry before amps |
| Rack spend | Retired late | Rack age vs burn rate | Rotation schedule |
| Claims | Burn escapes polished over | Audit failure rate | Ship gate on first articles |
Engineer notes
- One variable per corrective action; verify with the confirm-by column.
- Records beat memory: log every trial on the tank card.
- Two failed actions in a row is a senior call — escalate with your log.
Safety: chromic acid mist is a carcinogen and burns skin. Exhaust running before load-in, face shield, and immediate first aid for any chrome burn.
FAQ
Why does chrome rework cluster in one rack family?
Contact and geometry age together; rack rotation costs less than replate hours.
What proves a geometry fix paid back?
FPY by defect family over four weeks vs the replate hours saved — one chart.
Who owns burn investigations?
The senior on shift with the tank card; audits check the card, not the memory.