Pre-treatment in coating lines.

Coating of metal parts and objects requires careful pre-treatment, in particular with today's high quality demands. Many process steps, like cleaning or degreasing, rinsing and phosphatising, are required, prior to applying any coating, to warrant the paint quality required.

These large installations are operated by specialist and process large volumes of metal products. Consequently, large amounts of dirt and oil are brought into the process, causing the necessary problems. It is not uncommon that in a matter of weeks, dirt gets dragged along from bath to bath showing up at the last rinsing stage, before the coating is applied. The only solution than is to replace all the baths, a very labor intensive and expensive operation, to make a fresh start

The only proper way to address this problem is to control the level of oil and dirt in the first step; the cleaning stage. It is unavoidable that fluid (cleaner, rinse water etc.) is dragged along with the parts as they are transferred through the installation. If this fluid is dirty, dirt gets dragged along.

Cleaners that emulsify and absorb oil and dirt, by definition, hold more pollution and will make conditions worse.

Oil control.

The first, essential, step is oil control. Oil does not only present a threat to the bonding of paint to the surface of the part, but also causes dirt to remain suspended and deposit on parts and stick to them. A commonly observed condition; dirty, black oil floating on the surface of a cleaning bath, is unacceptable and should be addressed effectively.

Suparator® is very effective in removing oil from these baths. With the Skim & Treat® concept, oil can be removed at low concentrations and the build up of oil can no longer occur. See this case study for a detailed report with pictures.