After printing, sublimation digital printing ink uses heat to turn the dye from a solid state into a gas, which then transfers to the surface of the substrate. In this process, the particle size, distribution, and stability of the dye particles in the ink affect nozzle smoothness, pattern clarity, and transfer efficiency. When particles are too large, sedimentation, nozzle clogging, rough edges, and color fluctuations are more likely to occur. Therefore, the grinding step must open up dye agglomerates and bring the particle size into the submicron range. A common target is D50 <= 200 nm, while D90 and distribution width should also be considered.

If a traditional sand mill uses larger grinding media, the shear and impact effects are limited, more circulation passes are required, and heat buildup is more likely to accumulate. Sublimation dyes are sensitive to temperature, and prolonged high temperatures can affect hue, solubility, and dispersion stability. Equipment selection needs to be considered around fineness, temperature, dispersion efficiency, and batch stability.

In this case, the RUCCA N series nano sand mill can be an option. This series can be adapted to 0.1-0.3 mm grinding media and, with a suitable bead-material separation structure and grinding chamber, can stably achieve D50 <= 200 nm. Small-sized media are numerous and have dense contact points, which helps with submicron grinding. The equipment can use zirconia beads or ceramic beads, and the grinding chamber liner can be made of ceramic, polyurethane, and other materials to reduce the impact of metal ions on the ink system. By adjusting linear speed, flow rate, media filling rate, and grinding passes, process matching can be carried out for different formulations.

Temperature control is an important part of sublimation ink grinding. The RUCCA N series has an internal and external dual cooling system. The internal cooling and external cooling work together to keep the equipment temperature within a controllable range during long-term operation, reducing the risk of deterioration of heat-sensitive dyes. For continuous production, cooling capacity is related to flow rate, viscosity, and grinding energy, and must be set in a coordinated way to avoid local overheating.

Front-end dispersion also affects the grinding result. When paired with the IDS online dispersion system, powder suction and liquid wetting are completed in a relatively short time, enabling dust-free powder feeding and reducing dust flying and material loss. After the powder is instantly wetted, the agglomerate size is smaller, and the dispersant can take effect more quickly. In this way, after entering the sand mill, the subsequent grinding passes can be reduced by 30%-50%, which helps reduce energy consumption and wear and also makes color and particle size more stable between batches.

Actual model selection cannot rely on only one parameter. Dye type, solid content, solvent ratio, dispersant type, viscosity, initial particle size, target capacity, and allowable temperature rise all affect the configuration. It is recommended to send samples to RUCCA for testing and, based on the specific formulation, test grinding media specifications, equipment models, flow rate, linear speed, and circulation method. Through particle size testing, viscosity changes, filterability, inkjet testing, and storage observation, confirm the process route. The configuration obtained in this way is more suitable for production needs and can also reduce adjustment time after going online.

In addition, equipment materials and cleaning and color change are also worth noting. Sublimation ink systems may contain organic solvents or water-based components, and compatibility with the grinding chamber, piping, and seals will affect service life and cleanliness. RUCCA can provide corresponding material solutions according to material characteristics and assist in developing cleaning procedures. For the transition from laboratory to mass production, media and parameters can first be determined on small-scale test equipment and then scaled up to production models. If you have a specific formulation and target particle size, it is recommended to contact RUCCA to send materials for testing, and technical personnel will recommend a suitable configuration based on your formulation.

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