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 |
|---|---|---|---|
| Deposit cracks on bend test | Deposit stress high: brightener overdose | Bend test + Hull cell | Hull cell, cut dose per curve |
| Craze lines after chrome | Over-bright deposit meets chrome stress | Timing: before/after chrome | Dose down before chrome audit |
| Powdery, flaky deposit | Metal or pH out of band | Titration + pH | Correct per TDS |
| Brittle only late in bath life | Organics + breakdown products | Turnover count | Carbon trial / plan rebuild |
| Brittle on thin parts only | Over-plating thin sections | Thickness by part class | Split families by weight |
Cost, metrics and defence
| Cost line | Driver | Metric | Lever |
|---|---|---|---|
| Field failures | Brittle deposits in service | Returns by defect family | Bend-test gate per load |
| Scrap | Over-plated thin parts | Thickness variance by class | Family split loads |
| Chemical spend | Overdose corrections | Brightener L per Amp-hour | Consumption curve |
| Claims | Cracked under plating | Claim photos vs bend log | Records settle disputes |
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: nickel bath chemistry is a sensitiser; bend tests flick sharp metal shards. Gloves, shield at the tank, eye protection at the bench.
FAQ
Where does brittleness cost most?
Field returns after chrome: the bend-test gate per load is far cheaper than a claim.
Which number tracks dose discipline?
Brightener L per Amp-hour vs the curve; drift predicts brittleness weeks out.
Family split loads — throughput cost?
Minor versus scrap and returns; the dose curve pays for the extra handling.