The manufacturer of AL Foil for transformer tells you that the oil stain refers to the excessive oil on the surface of the aluminum pin after rolling. And it has excess oil except for the rolling oil film, which is visible to the naked eye during the slitting production and product inspection process. 

The AL Foil for transformer manufacturer tells you that these oils are mainly caused by throwing, splashing, splashing, dripping on the box surface at the roll neck or at the exit of the rolling mill, abnormality of the roll cleaner of the rolling mill, and oil dripping from the gauge head of the rolling mill, etc., and are often relatively large. Dirty ingredients are complex.
This kind of oil pollution will bring great harm to the surface of AL Foil for transformer: First, because most of the finished aluminum boxes are used as decoration or packaging materials, there must be a clean surface; Second, its thickness is thin, and it is easy to form bubbles during subsequent annealing shape, and due to the large amount of oil, too much residue is formed here, which affects the use.
The number of oil stain defects is an important index to evaluate the quality of AL Foil for transformer.