Alcohol-free or low-IPA dampening is a controlled change to the water-ink system, not a direct switch to zero IPA. Water quality, solution concentration, temperature, roller condition, ink, and press settings must work together. Contamination or unstable mechanics become more visible after IPA is reduced.
Establish a stable baseline
Record a complete stable production run before changing anything: current IPA percentage and mixing method, solution concentration, pH, conductivity, water temperature, water source, circulation cleaning/filters, press, plate, ink, stock, speed, makeready waste, common defects, and cleaning frequency. Use the same calibrated meter and sampling point for trend records.
Controlled implementation
- Clean the tank, circulation route, filters, and related roller system according to the press and chemical safety requirements.
- Prepare fresh solution according to the actual product TDS. Do not use another supplier’s ratio as a substitute.
- Reduce one IPA step at a time on a stable representative job. Keep plate, ink, stock, speed, and other settings unchanged.
- At every step, record non-image cleanliness, water-ink balance, density, emulsification, makeready waste, cleaning, and pH/conductivity/temperature trend.
- Accept a step only after stable performance through a representative shift. If a persistent problem occurs, return to the last stable condition and diagnose the cause.
Troubleshooting order
| Symptom | Check first | Avoid |
|---|---|---|
| Persistent scumming | Plate, concentration, tank/filter condition, roller cleanliness and pressure | Repeatedly raising water feed or restoring all IPA at once |
| Mottling or unstable density | Emulsification, water feed, rollers, speed, and stock | Changing concentration, ink feed, and roller settings together |
| Drifting pH or conductivity | Mixing accuracy, water source, replenishment, contamination | Adding concentrate from one isolated reading |
| Uneven wetting | Roller surface/pressure, filtration, spray condition | Replacing chemicals before checking mechanics |
Safety and acceptance
IPA is volatile and flammable. Follow the SDS, ventilation, fire-control, storage, and PPE requirements. Specific concentration, pH, conductivity, and IPA reduction targets must come from the actual TDS, press manual, water quality, and trial data.
Accept only when fine text and screens remain clean, density stays on target without abnormal ink feed, waste is acceptable, and shift-level solution readings are explainable and traceable.