New technologies for corona and tribo gun
Equipment manufacturers have tried many different guns and nozzles to optimize the coating process over the years. However, most new technologies are developed to meet the needs of specific market requirements.
A corona gun technology that has been used in different forms is the grounding ring or sleeve. This grounding ring is usually located either inside or outside the gun at some distance from the electrode and opposite the product being coated. It can be located on the gun itself or an attachment that surrounds the gun. The effect of using the grounding ring with the corona gun is to develop a higher, more consistent current draw from the electrode. This results in two beneficial advantages. The powder can be applied at heavier film thicknesses and without the orangepeel appearance typically associated with corona guns that apply thick coatings.
Several developments in tribo gun nozzles are also available. Flat nozzles with several slots allow powder to exit the gun at lower velocities while creating additional contact points at the exit of the gun to charge the powder.
Nozzles with many flexible discharge points allow powder to be directed into specific areas of the product. Other nozzles that have been used successklly are available to meet specific needs. Tribo guns have the flexibility to adapt many different types of nozzles because no electrode is required in or near the powder stream.