Coating uniformity improves when three variables are locked: constant spray rate per gun, constant atomization (liquid-to-air ratio), and even product exposure to the spray zone. Gun hardware and gun position decide all three.
The levers, in order of impact
- Spray rate discipline: graduated, repeatable flow adjustment per gun — multi-gun bars must deliver the same rate.
- Atomization stability: independent liquid and air lines keep droplet size constant while you change throughput.
- Exposure uniformity: gun centering (Wurster) or spray-bar geometry (pans) decides whether every pellet sees the same spray flux.
- Verify by sampling: film-thickness data from a sampling trial locks the settings before production.
FAQ
Why does my tablet coating show colour variation?
Usually uneven spray flux: guns delivering different rates, drifting atomization air, or worn nozzles. Calibrated multi-gun bars with split air control remove the main sources.
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