UV Powder Coating
I am attempting to find out as much as possible about UV powder coating, including the process itself and the equipment required. R.C.
Well how’s the search going? By now you probably have all the answers you were looking for. This is especially true, since this column will be printed in November and you asked your question in April. This is the normal lead-time given the astounding backlog of questions the magazine has collected for me to answer. All I have to say is, “It’s nice to be wanted.”
The UV powder coating process uses all the normal cleaning, pretreatment, drying and spraying equipment used for any other powder coating system. The only difference lies in the method of curing. A specially formulated UV cured powder coating is applied to the substrate material using the normal electrostatic spray techniques. The product is then conveyed to an IR oven to melt and flow the powder at a product surface temperature of around 220F. This step turns the coating from a solid into a liquid allowing the coating to wet the surface and form a smooth and continuous coating. The product is then conveyed to a UV “oven” where UV energy activates the photoinitiators in the coating to fully cure the coating. The product then emerges ready to perform up to its formulated coating properties.
Since the product is exposed to a lower temperature (220F) for a short amount of time, temperature sensitive products can be coated using this process. However, because IR and UV energy travel in a straight line, the products coated with this process must be relatively simple shapes and fairly symmetrical. Properly positioned emitters will ensure that all coated surfaces are exposed to the IR and UV energy sources.