All Articles Food CPG The life of a can: How an aluminum can is made

The life of a can: How an aluminum can is made

4 min read


This series is sponsored by CMI, where gray is the new green. Want to know why? Download our sustainability paper to learn more about how cans stand alone as the sustainable solution for 21st Century Packaging. Pass it on.

Each day, pallets full of empty aluminum cans roll into bottling plants and roll out again full of beverages destined for supermarket shelves and convenience store coolers. By the time consumers place cases and six-packs in their carts, the cans have already completed the long journey that transformed them from sheet metal to beverage container.

Aluminum can usage has risen rapidly since the containers were first introduced in the beverage world in 1960, and today they’re the most common drink containers, according to the Can Manufacturers Institute. Beverage innovation as well as new manufacturing technology has boosted their use, and containers that typically held only soda and beer are now called into service as containers for everything from energy drinks to iced coffee.

Each of the 100 million light-weight aluminum cans manufactured at Ball Corp.’s factories each day starts life as a tiny part of a massive roll of aluminum sheeting that can weigh up to 15,000 pounds. As shown in this 10-minute video, the sheet is unrolled on one machine, then fed through another that applies a thin film of lubricant before it’s fed into a cupping press. The press uses one tool to cut circular pieces out of the sheet and another to punch the pieces through a die to create the cups, which at this stage are shallow metal bowls about the size and shape of a hockey puck.

Another machine uses a bar to push the cup through a series of successively narrower dies to stretch it out and form the body of the can, and then press the can against a mold to create the domed bottom. In slow motion, the process looks like a metal bar being threaded through a series of heavy weights, much like the weights you’d hang on a barbell at the gym. At the end, the can is deposited in a slot on a metal wheel that delivers it to another machine that trims it down to size.

Workers do another quality assurance inspection before the cans get a six-stage washing process and head to the printer that will brand it with the art that tells consumers what’s inside.

The art is artier these days, thanks to the development of high-resolution printing processes that put photo-quality graphics directly on the cans. Other big innovations include the invention of resealable aluminum bottles such as Ball’s screw-top Alumi-Tek, but the industry has also made and continues to make incremental improvements in the process, says Ball spokesman Scott McCarty.

“Can quality became excellent some time ago and is expected now,” he said. “There are steps built into the can-making process that kick out any questionable cans, so while we, of course, focus on quality, it is assumed to be very high and only gets attention if any problems pop up.”

Instead, innovation these days is focused on finding ways to make the process even faster and lighter. Aluminum cans are already much lighter than they were in the early days. The average weight of an aluminum can in 1970 was 0.048 pounds compared to 0.029 for today’s model, McCarty says.

The industry has also gotten much better at using recycled aluminum, which uses 95% less energy to produce than virgin aluminum. On average, about 68% of the metal in Ball’s aluminum cans now comes from recycled content, McCarty says.

Now that we know more about where cans come from, next month we’ll take a longer look at the industry’s efforts to make the process even greener.