Vacuum processes for the Canning industry
The manufacturing process of aluminium cans for the beverage industry is strongly dependent on vacuum. Aluminium cans are non-magnetic, so vacuum becomes the most practical way to hold them. All through the process, when the can is formed, transported and painted, vacuum is at work.
- Blanking and Deep-drawing
- Wall-ironing and end forming
- Trimming : In the trimming machine, the can is held by a vacuum plate, set in rotation and then moved axially until it reaches the required trimming height. Then the movable cutter unit is guided to the can. Whilst the can rotates precisely once, the can rim between the upper and lower cutter is cut off burr-free at the required height. The rings cut off are removed by vacuum, pressed into bales and returned to the tin plate production facility ➡ vacuum holding and conveying
- Washing and drying
- Outside coating: The cans are coated on the outside as protection against corrosion and in order to apply a decorative design. 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 ➡ vacuum pick & place
- Printing: The can is positioned on the mandrel rolls synchronously over the blanket and absorbs the complete decorative design with all the ink colors from it. ➡ vacuum pick & place
- Internal coating: Inside the internal coating machine, the can is conveyed to a coating turret and positioned on a vacuum plate. It is set into rotation and passes two spray guns, the first one which coats the lower section of the body and the second the body and the base. ➡ vacuum pick & place
- Necking: The diameter of the can which is still cylindrical needs to be reduced in the upper section to accommodate the smaller end.
- End coating: The metallic bright can end is coated from the outside in the end coating machine ➡ vacuum pick & place
- Testing for holes, flange cracks and for internal defects.
That means canning line have high throughputs and require high-capacity vacuum pumps, while major problems present on site are high maintenance costs, up time of the plant as well as high metal sheet rejection rates
- Operating vacuum level for the application: 200-400mbar(a)
- Pumping speed : from 1200 to 3000 m3/h
- Reliable machines
- Control the maintenance costs
- Clean environment
And Atlas Copco VSD⁺ pumps are up for the task.
A range of solutions and technologies relaying on best in class design for high reliability and easy maintenance coupled with intelligent control.