Fast Color Change

Q. I have been hearing and reading a lot about fast color change for powder. Our powder booth takes about 30 min to change from one reclaim color to another. We are thinking of making a change, but I wondered how much production time we could gain if we invest in new equipment. What are my options, and how fast can you change color in a powder booth? N.L.

A. The speed of color change in a powder system depends on what equipment you have; whether you spray with manual only, automatic only or both; and whether or not you will reclaim the powder for reuse. The booth and application package can be designed for rapid color change.

It starts with the issue of reclaim of powder. If you need to reclaim the powder for reuse, the booth design has to be simple to clean. The airflow arrangement, booth wall construction and interior design can be engineered to make it easy to clean in a short time and to thoroughly remove all residual powder. Typically, this will mean using downdraft airflow, a cyclone recovery system and composite wall construction that is shaped for easy and rapid blow down. If you have short runs of various colors and do not plan to reuse the over-sprayed powder, the booth construction is less critical.

If you use manual spray only, the best place to invest your money is a dial system to select color from a manifold that connects to dedicated feet hoppers. A manual gun can be purged in less than 1 min using this type of system. If you use automatic guns, there are several features that can be used to speed up color change. A manifold system can be used to blow out the pumps, hoses and gun interiors. This is usually a component of a powder feed center that contains the delivery source and facilitates rapid change over of the feed container. A gun mover that pulls the guns back out of the booth can be used to withdraw the gun barrels from the booth during interior cleaning. Nozzles can be arranged along the gun slot to blow powder from the exterior of the gun barrels as they are withdrawn.

So what is the bottom line in color change if you have the right options? In a manual-only system with no reclaim for reuse you can change colors in less than 1 min. In an automatic system with no reclaim you can change color in 3-7 min. In a system that goes from reclaim-to-reclaim you can color change in 12-20 min. All of this depends on owning the right equipment and being trained in how to use it. A couple of cautions:

1. Radically dissimilar colors will run at the higher end of the range, so going from light brown to dark brown is faster than white to black.

2. Some powders are problematic in any powder system and may be uniquely slower and more likely to cross-contaminate than the other 98 percent of what you run.

3. All of these features cost money, so you have to do a cost evaluation to make sure the payback is there.