Tribo And Corona
The difference between tribo & corona spraying systems.
Understanding the differences between corona and tribo charging, assists in deciding which technology is best for an application.
In corona charging, a high voltage potential is developed at an electrode located in or near the powder stream. The powder particles become negatively charged and are attracted to the grounded substrate.
– are very successful in achieving a consistent film build especially with thin film thicknesses, thanks to consistent charging
– finishing problems such as orange peel & back ionization are possible because of the high electrostatic charge
– powder output per gun can easily be adapted
– ability to adapt to conveyor line speed (both low and high speeds) with the same amount of guns, as powder output per gun can easily be adapted
– compatible with most powder coating types
When tribo spraying, contact between the gun and the powder particles causes friction. The powder coating gun is internally covered with a negatively charged material (eg. Teflon) that positively charges the powder particles and has them release their positively charged energy.
– easier to use in case of higher layer thickness needed. No back ionization or orange peel (because there is no electrostatic field)
– operate at lower powder output
– more guns needed to obtain the same result of corona spraying at high speed conveyor lines, due to the gun operating only at a low(er) powder output – only a limited range of powders can be used for tribo spraying
– specially designed for complicated part forms (edges, corners, …) (see: the effect of Faraday cage)
– advantage in gun cleaning