Generally, pretreatment systems are designed to clean and etch a metal surface. The washer cleans the surface and etches a profile into the part’s metal. Paint adheres to the profile. Pretreatment takes place through several stages and each stage performs a function. Written procedures and specifications are determined by powder coating and cleaning chemical vendors. This gives users crucial information about proper part pretreatment during various stages. Power-wash systems are designed with nozzle-and-riser configurations. The risers are the piping materials that feed the nozzles. Generally, risers are spaced at 12 in. (30.5 cm) increments. The nozzles also are spaced at 12 in. (30.5 cm) increments. This pattern changes, depending on the substrate profile. Many varieties and configurations of washers are on the market. Osmosis is a natural phenomenon in which a liquid — water in this case — passes through a semi-permeable membrane from a relatively dilute solution toward a more concentrated solution. Conveyorized pretreatment washer systems take advantage of a consistent and efficient way of processing parts for cleaning.
By Gary Conner
By George N Bullen FSME