Material settling is a problem in the use of paint or any other material with suspended particles such as colored inks, dyes, etc. This problem causes suspended particles to account for the pigment, color, consistency and adhesion characteristics of the material. Materials with these properties are called suspensions and they are extremely common as they make up the majority of materials handled by spray and marking systems. If these suspensions are not moved or used frequently, gravity will get caught and the suspended particles will settle and start causing problems with the spraying process. Problems can range from clogged filters to affecting the repeatability of color or other features from part to part after parts are coated. So it's very important to remember: if you don't use the suspension for one run, keep them moving constantly.
A popular method of keeping the suspension moving is stirring. This is the optional method for smaller, simpler systems, such as manual automotive finishing systems with single guns and tanks. With pneumatic or electric agitators, you can keep materials in suspension and even adjust the agitation speed to account for different material viscosities.
If you have a more complex system, such as an automated system with multiple tanks, pumps and Spray Guns, then constant material circulation may be a good option for you. Typically used in non-contact marking systems, material circulation involves the use of a special gun with two material ports. This allows material to circulate through the system even when it is not sprayed. On automatic circulation systems, Diaphragm Pumps are often used to keep the material in motion. Use these quick tips to prevent paint from settling in the Spray Gun.
