PPGI coil requires efficient degreasing and chemical treatment. Generally, hot alkaline solution is used for degreasing. For example, degreasing x 105Pa pressure spray using a 0.5~1.5% sodium hydroxide aqueous solution containing a small amount of sodium polyphosphate at 60 degree can also be removed by electrolysis.

surfaces and to provide a clean surface for chemical treatments. However, nylon brushes are not resistant to high temperatures and should be used below 60 degree . Chemical treatment is to form a conversion film on the surface of ppgi coil by pressure spraying or dipping. In order to obtain an ideal conversion film, different conversion fluids should be selected for different steel coils.

. In order to improve the corrosion resistance of ppgi coil, a chromate solution with a chromium content of {{0}}.1~0.5% is also required for passivation. The passivated conversion film has better performance, and Cr6 additive can inhibit the corrosion of ppgi coil. Treated wash water contains chromium or other harmful metals and must be purified before discharge.

1. Electroless coating treatment: Due to improper electroless coating process, the electroless coating film is too thick, the plate temperature is insufficient after drying, or the ppgi coil coated roller body is damaged, and yellow spots are formed after drying, resulting in ppgi coil color difference, especially light color.

2. Maali: Maalin epätasaisen sekoittumisen tai maalin viskositeetin suuren eron vuoksi eri tynnyreissä maali ulottuu syöttöaukon sivulta alustan paluuaukkoon, jolloin syntyy värieronauha. Lisäksi ppgi coil -maalin väriä vaihdettaessa erityisesti värikontrasti on suuri. ppgi-käämin värierot johtuvat epäpuhtaudesta ja saastumisesta.

3. Erikokoiset ppgi-käämin spanglit muodostavat raerajoille useita erikokoisia pieniä kuoppia, jotka vaikuttavat erityisesti vaaleiden värien värieroon ppgi-käämin pinnalla. Valitse alusta, jossa ei ole kiiltoa tai pieni kiilto aina kun mahdollista.