Changing colors during powder application

 

In any powder coating operation using multiple colors or powder types there is risk of contamination occurring during the change-over between powders.  However, it is possible to minimize this risk using well ordered cleaning procedures.

When performing a color change the cleaning operation should follow the same route as the powder does when spraying.  So, cleaning should begin with the hopper followed by the pumps, hoses and guns which in turn are followed by thorough cleaning of the booth enclosure.

Clean down is completed by cleaning or changing the recovery system.  All cleaning operations using compressed air should be performed inside the booth to ensure that the powder is contained, thus reducing the risk of airborne contamination.

The length of time that color changing takes can vary widely depending on the plant type and configuration.  For operations which require many color changes to be performed often and swiftly then it may be necessary to have multiple booths.  Alternatively most major equipment suppliers now offer booths with polyethylene sheeting walls which are replaced with each color change to eliminate cleaning of the booth.

Cyclone recovery systems are for the most part self-cleaning and require little maintenance.

In the case of cartridge systems it is necessary to color dedicate cartridge collector units.  If many colors are required it may be impractical to use a large number of units.