Beverage can making process: Training videos (Part 2)
In the second upload of a 14 part series of videos, CanTech Online continues its look at how a beverage can is produced. The latest videos show the washing, outside coating and printing parts of the process. Once again there is an explanation of each section of the process above each video. Keep checking back for new videos. Videos are courtesy of Ball Packaging Europe.The idea of these videos is to help those who are new to the industry to learn about can making.
Part 4: Washing
The wall-ironing lubricant used in the can forming process is removed prior to coating the can internally and externally. The cans are transported to the washer on a wide belt and conveyed through several washing chambers upside down.
In this way the outside of the can is rinsed with tap water supplied through the jets located at the top and the inside of the can by the jets located at the bottom. Immediately downstream of the washing unit, the can is dried with dry air at a temperature of approx. 200° in the drying oven.
Part 5: Outside coating
The cans are coated on the outside as protection against corrosion and in order to apply a decorative design. White, gold or transparent coating as well as aluminium-coloured coating can be used according to customer specifications. Generally the coatings are water-based.
The cans are spaced by an intake wheel and drawn on to the coating mandrel of the mandrel wheel by means of a vacuum. They are then set in rotation around their own axis by the rotation belt. The coating film on the coater cylinder is then transferred to the cans positioned on the rotating coating mandrels. The coated cans are then blown off the coating mandrels and transported to the drying oven on a magnetic conveyor belt. The coating is pumped from a coating container to the engraved cylinder which transfers the appropriate quantity to the rubber-coated coating cylinder from where it is transferred to the cans.
Part 6: Printing
The externally coated cans are spaced by the intake wheel, as in the coating machine, and drawn on to the mandrel wheel mandrels by means of a vacuum. The mandrels are set in rotation around their own axis by a rotation belt.
The can positioned on the mandrel rolls synchronously over the blanket and absorbs the complete decorative design with all the ink colours from it. The individual colours are transferred by the inking units to the blankets via ink boxes, various rollers and the cliché cylinder with mounted printing plate. The high pressure printing clichés only absorb ink in the parts in which they are raised. Therefore each inking unit presses one colour ink onto the rubber blanket. Prior to the can coming into contact with the blanket, all the ink colours are on the rubber blanket entering the inking section; here the printed image is mirror-inverted. The inks are transferred to the can by rolling the can over the rubber blanket and the printed image becomes positive. The printed cans are then blown off the mandrels and conveyed to the drying oven by a magnetic conveyor belt.