INK PRODUCTION SOLUTION
A POLYC ink production line combines powder induction and pre-dispersion, horizontal bead milling, letdown, filtration and filling. Inline dispersion can reduce milling time by about two-thirds and energy use by more than half, with reference throughput around 1,200 kg/h for NC white ink at about 40% pigment loading.
A practical guide to ink production using inline dispersion, horizontal bead milling, blending, filtration and filling equipment.
A production line normally combines liquid dosing, powder handling, pre-dispersion, wet grinding, letdown, filtration and filling. Each stage should be sized around pigment loading, binder system, viscosity, target fineness and batch frequency.
A conventional route uses a high-speed disperser before a vertical or horizontal bead mill. An integrated route can use an inline dispersion machine to induct, wet and de-agglomerate powder before horizontal bead milling, reducing the load on the grinding stage.
High liquid velocity creates a controlled vacuum for powder induction. The rotor-stator zone increases liquid surface area, wets powder rapidly and circulates the mixture for dispersion and de-agglomeration. A closed arrangement can reduce airborne dust and manual powder handling.
Disc bead mills are commonly selected for productive micron-scale grinding. Pin-type bead mills provide higher grinding intensity when narrow particle-size distribution or nano-scale targets are required. Mill volume, media size, tip speed, cooling and pass strategy must be confirmed by formulation.
For equipment selection, provide the liquid system, pigment type, solids content, viscosity, feed size, target fineness, batch size, hourly capacity, temperature limit and hazardous-area requirements. These inputs determine the process route and equipment configuration.
Ink formulations cover liquid inks (gravure, flexographic, news ink) and paste inks (offset, screen, UV). The choice between water-based, solvent-based or UV chemistry affects drying, viscosity, pigment loading and the required grinding intensity.
Horizontal bead mills distribute grinding media evenly and can load up to 80% of chamber volume. Traditional vertical mills suffer from gravity settlement of media, lower media loading and lower energy density.
| Aspect | Horizontal Bead Mill | Vertical Bead Mill |
|---|---|---|
| Media distribution | Evenly distributed, no gravity settlement | Beads sink by gravity, uneven density |
| Media loading | Up to 80% of chamber volume | Lower loading volume |
| Peripheral speed | Up to 13-16 m/s | Around 10 m/s |
| Energy density | High (Pv > 2 kW/L) | Low |
| Fineness | Nano and sub-micron achievable | General micron only |
| PSD | Narrow distribution | Broad distribution |
| Capacity example | PZP30: up to 500 kg/h for white/yellow | Slower throughput |
Inline dispersion improves pigment wetting and de-agglomeration, typically reducing milling time by two-thirds and cutting energy use by over 50%. In a TiO2 water-based trial at 55% solids and 45 deg C limit, the particle-size distribution after induction and 15-minute circulation reached the following values:
| D03 | D06 | D10 | D16 | D25 | D50 | D75 | D84 | D90 | D97 |
|---|---|---|---|---|---|---|---|---|---|
| 0.085 um | 0.092 um | 0.101 um | 0.115 um | 0.153 um | 0.224 um | 0.295 um | 0.344 um | 0.421 um | 0.987 um |
The PZP series covers laboratory to production sizes for 5-10 micron applications such as architectural coatings, gravure inks, flexographic inks and pigment dispersions.
| Model | Volume (L) | Motor Power (kW) | Peripheral Speed (m/s) |
|---|---|---|---|
| PZP1 | 1 | 4 | 11.3 |
| PZB5 | 6 | 7.5 | 12.5 |
| PZB10 | 10 | 11 | 13 |
| PZB20 | 20 | 22 | 13 |
| PZB30 | 30 | 30/37 | 13 |
| PZB60 | 60 | 75 | 14 |
| PZB150 | 150 | 160 | 14 |
The PZB pin-type series delivers higher grinding intensity for nano-fineness applications such as inkjet ink, automotive paint, carbon black paste and battery slurries.
| Model | Volume (L) | Motor Power (kW) | Peripheral Speed (m/s) |
|---|---|---|---|
| PZB2 | 1 | 5.5 | 12 |
| PZB6 | 6 | 15 | 14 |
| PZB10 | 10 | 22 | 14 |
| PZB20 | 20 | 30 | 14 |
| PZB30 | 30 | 45 | 14 |
| PZB60 | 60 | 75 | 15 |
| PZB150 | 150 | 160 | 16 |
A reference NC white ink route combines an IDS inline dispersion machine with a PZP disc bead mill. Solvent and varnish are charged first; TiO2 is inducted powder-side at high rate, wetted and circulated before fine grinding.
Inline powder induction replaces manual powder handling and a separate Cowles pre-mix loop. In production references it has cut milling time by about two-thirds and reduced energy use by more than half.
The PZP disc mill uses reverse-feeding agitator discs and a turbo discharge separation that keeps grinding beads away from the screen. This allows smaller media and a larger open screen area for high flow at low chamber pressure.
Pin-type mills run higher energy density and accept smaller media for narrow particle-size distributions. Combined chamber and inner-rotor cooling keeps temperature even, which supports a narrow PSD and stronger color strength at lower pigment loadings.
Select equipment based on target fineness, viscosity and batch frequency. Basket mills suit flexible color changes; disc mills are the workhorse for micron-scale production; pin mills are needed when nano fineness or narrow PSD is required.
The grinding stage follows the ink chemistry rather than the machine catalogue. The table below summarises the usual match between ink type, viscosity and target fineness, using the references described on this page.
| Ink type | Typical viscosity | Fineness target | Recommended grinding stage |
|---|---|---|---|
| Gravure, solvent or water-based | Low | Below 5 microns in production; NC gravure below 1.25 microns in reference trials | Disc bead mill or pin mill |
| Flexographic, solvent, water or UV | Low to medium | Below 5 microns | Disc bead mill |
| Inkjet and digital | Low | D90 below 200 nm | Pin-type nano bead mill |
| Offset paste | High | Controlled by three-roll gap | Three-roll mill rather than a bead mill |
Ink quality is decided long before the filling head. The checks below are normally applied at the stages shown, and each result should be recorded against the batch so that a drift is visible before a customer sees it. The Ethiopia gravure ink project is a worked example of the same sequence on a 200-300 kg/h line.
| Check | Method | Stage |
|---|---|---|
| Fineness of grind | Hegman gauge or particle-size analyser | After milling |
| Particle size distribution | Laser diffraction, reported as D50 and D90 | After milling and at letdown |
| Viscosity | Rotational viscometer at working temperature | After letdown, before filtration |
| Colour strength | Drawdown against a retained reference standard | After letdown |
| Filtration integrity | Inspection of bag or cartridge filter after the batch | Before filling |
Liquids are charged first before pigments and additives are introduced under controlled shear. The objective is complete wetting without dry pockets, excessive air entrainment or a viscosity peak that prevents stable transfer to the mill.
The mill reduces agglomerates under controlled media loading, flow, speed and cooling. Samples should be compared at equal temperature using the same particle-size or fineness method before throughput is increased.
Resin, solvent, water or additives are adjusted in the finishing vessel. Final viscosity, shade and solids are confirmed before filtration removes oversized contamination and the product moves to filling.
A disc mill supports productive continuous grinding for gravure, flexographic and general industrial inks where stable micron-scale quality and high circulation flow are required.
A pin rotor creates higher grinding intensity and accepts smaller media for narrow particle-size distributions in inkjet, automotive, carbon-black and other fine dispersions.
A basket mill combines dispersion and grinding in one batch vessel. It suits frequent color changes, flexible batch sizes and plants that prioritize straightforward cleaning.
The formulation route determines materials, safety controls and the preferred grinding system.
| Ink type | Process characteristics | Typical equipment route | Key review point |
|---|---|---|---|
| Solvent-based ink | Resin solution, organic solvent and pigment | Closed disperser + horizontal bead mill + filter | Hazardous-area classification and seal compatibility |
| Water-based ink | Water, resin or emulsion, pigment and additives | Inline or high-speed disperser + disc bead mill | Foam control, corrosion and microbial management |
| UV ink | Reactive oligomer, monomer, pigment and photoinitiator | Temperature-controlled pre-mixing + pin bead mill | Heat exposure, viscosity and light protection |
These are preliminary engineering ranges, not guaranteed results. Material trials determine the final selection.
| Equipment example | Operating mode | Indicative production reference | Typical quality objective |
|---|---|---|---|
| 1000 L basket mill system | Batch | 500-1000 L working batch; evaluate roughly 45-120 minutes | Approximately 5-20 micrometres |
| 20-30 L horizontal disc mill | Continuous or circulation | Approximately 100-600 L/h depending on formulation | Approximately 5-10 micrometres |
| 20-30 L pin bead mill | Continuous or circulation | Approximately 40-250 L/h depending on viscosity | Fine micron to submicron range |
Use a calibrated fineness gauge for routine production checks and particle-size analysis when a distribution target is specified. Record sample temperature because viscosity and apparent fineness can change as the batch warms.
Viscosity must be measured with an agreed spindle, speed and temperature. Shade, color strength, gloss, solids and density should be checked against the approved method. Final filter rating is selected against pigment size, product viscosity and filling requirements rather than chosen as a universal value.
A useful production record connects raw-material lots, charging order, dispersion time, mill settings, sample results, filtration pressure and accepted output. This makes formulation variation distinguishable from wear, cooling or operating changes.
Uneven dispersion often begins with poor wetting, an unstable feed viscosity or powder charging faster than the liquid can accept it. Low grinding efficiency can result from unsuitable media size, low media loading, excessive flow, worn agitators or inadequate cooling. Foam is addressed by reducing air entrainment, reviewing pump return position, controlling shear and confirming that any defoamer is compatible with the formulation.
Change one operating variable at a time and sample consistently. Increasing speed or extending time without confirming temperature, viscosity and media behavior can consume more energy without improving saleable product quality.
FROM THE PRESENTATION
RELATED EQUIPMENT
The IDS Inline Dispersion Machine is a dust-free, continuous in-line disperser that rapidly mixes and disperses solids and liquids using a rotor-stato
View equipment →Static disc bead mill for ultrafine grinding, supporting media down to 0.1mm with static centrifugal discharge.
View equipment →Horizontal pin-type bead mill for nanometer-range grinding, supporting media down to 0.2mm with centrifugal separation and force cooling.
View equipment →Ink Production Line: Semi-Automatic or Fully Automatic, Built to Your Capacity
View equipment →FREQUENTLY ASKED QUESTIONS
A typical line combines pre-dispersion, bead milling, letdown, filtration and filling. The exact route depends on the ink chemistry, viscosity, target fineness and production mode.
Choose a horizontal bead mill for continuous production and stable high throughput. Choose a basket mill for flexible batches, frequent color changes and simpler cleaning.
Zirconia media in approximately the 0.3-1.0 mm range is common, but media size and density must match the mill, pigment, feed size and target fineness.
Prepare a stable pre-dispersion, control slurry viscosity and temperature, select suitable media loading and maintain consistent flow. Inline powder induction can improve wetting before milling.
It depends on the printing process. Gravure and flexographic inks are commonly specified below 5 microns, while NC gravure references reach below 1.25 microns in production. Inkjet and digital inks require sub-micron grinding, typically D90 below 200 nm, which is why a pin-type nano bead mill is used.
In the letdown or finishing vessel, resin, solvent, water and additives are adjusted until the specified viscosity and solids content are reached. Viscosity is measured at working temperature before filtration, because a reading taken hot will not match the customer specification.
The mechanical arrangement can be similar, but the electrical and sealing specification is not. Solvent-based inks require explosion-proof motors and controls, solvent-resistant seals and appropriate ventilation, and cleaning between chemistries must be planned into changeover.
Throughput follows the ink type and pigment loading. In the reference route described on this page, NC white ink runs at around 1,200 kg/h at about 40% pigment loading, while a small-batch gravure line may be sized for 200-300 kg/h. Both figures depend on the target fineness and the number of passes.
Consistency comes from controlled pigment dispersion, a stable particle-size distribution, weighed letdown additions and a retained reference drawdown. Recording mill parameters with each batch makes a drift traceable to a specific stage rather than to the finished product.
White ink can often reach target fineness in a single pass through a disc bead mill, which suits high-volume production. CMYK and other colours typically require recirculation, trading throughput for a narrower particle-size distribution and lower peak temperature.
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