GOOD EARTHING OF THE OBJECT
Conventional electrostatic powder application leads to large quantities of negative charges being transferred to the object. If this large surplus of electrons cannot be efficiently earthed, the coated surface rapidly develops a powerful negative charge thus repelling the negatively charged powder from the spray gun. Consequently, without sufficient earthing it becomes impossible to build up a thick layer of powder with good flow and finish, rapidly and efficiently.
GOOD EARTHING OF SPRAYING EQUIPMENT
To ensure plant safety, it is absolutely essential to fully and effectively earth spray equipment, spray booths, and related equipment. This ultimately maximizes the avoidance of high voltage discharge and the possibility of resultant electrical sparks.
Relative humidity within the working environment is of great significance for spraying efficiency. Ideal relative humidity being 45-55%. Only clean, dry compressed air should be supplied to powder coating equipment.
OTHER FACTORS INFLUENCING SPRAYING EFFICIENCY
Spraying efficiency can be expressed as the percentage of sprayed powder which adheres to the object at the first application attempt. Maximum spraying efficiency provides several advantages, both technical and economic.
The following are the representative of the most important factors that influence spraying efficiency.
- Spray gun positioning
- Hanging technique
- Powder recycling
- Addition of virgin powder