What this sets up
A bath parameter is one measurable chemistry value. For an EN bath the typical parameters are:
- pH
- Temperature
- Nickel concentration
- Hypophosphite concentration
- Stabilizer concentration
- Complexing agent concentration
- Phosphorus content (medium-phos, high-phos)
Each parameter has a target, min, and max. Daily chemistry logs capture readings against these specs.
Menu: Plating → Configuration → Bath Parameters.
Creating a parameter
Click + New:
| Field | What to set |
|---|---|
| Name | Plain English ("pH") |
| Code | Short code (PH) |
| UOM | pH units / °C / g/L / mL/L |
| Process Type | EN / chrome / anodize / etc. — which bath types this parameter applies to |
| Target | Middle of the spec window |
| Min / Max | Spec limits |
| Action Limit Low / High | Tighter limits that trigger a warning, not a reject |
| Test Frequency | Every shift / daily / weekly |
| Test Method | Titration / pH meter / Hull cell / SPC |
Min/max vs. action limits
- Min/Max: hard spec. A reading outside = Out of Spec = bath locked.
- Action Limit Low/High: soft warning. Reading here = "attention, trend watching, replenishment needed soon".
Two-tier alerting. Operators don't get alarm fatigue, real out-of-spec gets attention.
Process-type scoping
EN and chrome baths have completely different parameters. A parameter record is scoped by process type so the chemistry log form for an EN bath only shows EN-relevant parameters.
Linking to process recipes
Recipe steps can reference parameters — "Before starting, verify pH within 4.5-5.0" — and the recipe tree's operator-input definitions can pull parameter names and spec ranges.
Calibration + test equipment
Each test method has an associated calibration requirement:
- pH meter → daily 2-point calibration
- Conductivity probe → weekly check
- Titration apparatus → solution certification
Links to fp.calibration.record — chemistry log won't accept a reading if the test equipment calibration is expired.
Parameter history
Baths keep a full history of readings per parameter. From a bath record:
- Chemistry tab → recent readings + target
- Trends tab → line chart per parameter over time
- Highlights out-of-spec and action-limit crossings
What can go wrong
Operators log a value out of spec, bath locks
System behaviour as designed. Either:
- Replenish to get back in spec, re-test, unlock.
- Escalate to shop manager — maybe the spec is wrong for this bath age.
Parameter spec changed after a batch already plated
Historical readings keep the spec that was valid at logging time. New spec applies going forward.
Multiple baths share a parameter config but have different spec windows
Right now specs are at parameter level, not bath level. If truly different, create a second parameter record ("pH EN aged" vs. "pH EN fresh") and link to baths accordingly.