How to ensure successful powder coating
Good Earthing of the Object
During application of electrostatic powder coating it generates a large quantity of neegative charges being transferred to the object.Supposed these electrons could not be earthed efficiently,the coated subject surface rapidly develops a powerful negative charge which thus repel the negatively charged powder from the spraying gun.Thus,as a result of unsufficient earthing it becomes impossible to build up rapidly and efficiently a thick layer of powder with good flow and finish.
Inadequate earthing can easily be recognized by little or no powder accumulation around the hanging point of the object being coated.
Good Earthing of Spraying Equipment
To ensure plant safely, 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.
With friction charging equipment, good earthing of the spray gun is decisive for successful application. As the powder becomes positively charged, the electrons that are stripped away must be earthed. Without effectively earthing the spray gun, negative charges will accumulate and powder will then be allowed to pass through the gun without being charged.
Relative humidity within the working environment is of great significance for spraying efficiency. Ideal relative humidity being 45-55%. A quicker build-up of the powder layer and more even coating thickness are two of the advantages achieved by controlled humidity. Relative humidity can be measured with simple and inexpensive equipment.
Compressed Air Quality
Only clean, dry compressed air should be supplied to powder coating equipment. The quality of the compressed air can change the electrostatic charging and transporting properties of the powder. Impure compressed air may also cause visual defects in the coating.Pressurized air must be free from oil, water and as dry as possible.