Before powder coating process, parts must be as clean as possible to remove oil or rust on surface. Some customers will choose shot blasting, and most customers prefere chemical pretreatment---use chemical liquid to remove oil or small amount of rust.
Spray pretreatment is not good for all types of parts. Dip tank pretreatment is more economic, and reliable for cleaning parts.
Here below is a new pretreatment line for UK customer.
https://youtu.be/R431fLl4PwU
