The beverage cans used in daily life are composed of two parts: a can body and an easy-open lid. In the production of two-piece aluminum cans, can washing plays a very important role. First of all, the washing tank thoroughly cleans the greasy stains and the inherent oxides and attachments of the board during the forming process of the cans. Secondly, this is to process the surface of the can body to prepare for the subsequent printing and internal coating. In addition, it also pre-processes the cooking of the high-temperature tank.
1. In the pre-washing stage, the purpose is to remove the oil and other surface dirt adhering to the surface of the tank body. Pre-washing will help reduce chemical costs and improve overall cleaning capabilities. In the pre-washing process, soluble emulsified oil, organic oil, etc. are separated out and float on the surface of the water tank. Through water replenishment, most of the separated oil will flow to the sewage system through the cylinder overflow groove. By adding an acidic cleaning solution and maintaining the pH at around 2, it will help to keep the pre-washed tank wall and bottom clean.
2. In the pickling stage, the cup-punching oil, stretching oil, mechanical oil, aluminum chips, aluminum powder on the surface of the can, as well as various other surface oxides, organic particles, inorganic substances and other contaminants attached to the surface of the aluminum can will Will be removed, which is to prepare for the surface treatment and chemical film formation stage. If the above-mentioned contaminants cannot be completely removed, it will lead to incomplete surface treatment in the subsequent process, resulting in a variety of potential quality problems such as poor internal and external adhesion of the product, high conductivity, and poor surface printing.