by Melissa Donovan
Direct printing to aluminum cans offers durable, seamless, full-color messaging. With demand at an all-time high for niche product lines, personalized options, and so much more, digital technologies are perfectly positioned as the key decorating devices. This is due to their speed, cost effectiveness for shorter runs and variability, as well as great quality and color.
Shown: IDS’ line of rotary printers can digitally print a standard aluminum can at varying production speeds to support short- to medium-length production runs.
Moving Forward
Over the last few years, direct digital printing to aluminum cans has taken off. This due in part to advancements in both the hardware and ink sets used.
On the hardware side, Sandi Baginski, creative director, Innovative Digital Systems (IDS), says features like edge-to-edge customization in a rapid print process allows the aluminum can and bottling industry the ability to incorporate vibrant, seamless, and complex designs directly onto their products.
“There is more aftermarket embellishment, especially for events. With the ease of use and the speed of modern UV printers, it becomes very cost effective to print designs on aluminum cans and bottles that are specific to events, and venues,” agrees Lon Riley, founder/CEO, The DPI Laboratory.
Printhead and related software technologies also play a role by “allowing for high drop printing, which offers better print quality on the shoulder of cans. These advancements allow suppliers to become more flexible with their product line and to offer seasonal designs, limited-edition decorations, and even personalized pieces, all advantages of a digital print process,” notes Baginski.
Met and Fixed
Aluminum cans present concerns that need to be considered during the decoration process. This includes handling as well as ink adhesion, and beyond that how the graphic remains on the can when out in the elements—i.e. a refrigerator or cooler. “Printing onto any substrate via a digital process requires considerations related to the surface,” explains Paul Edwards, VP of the digital division, INX International Ink Co.
Baginski points out that aluminum can be thin, soft, and malleable. “Extra care should be taken in assessing the process and tooling required to decorate the object to avoid product damage.”
Ink adhesion isn’t as challenging as other surfaces. “Aluminum tends to have very good adhesion with most inks. For decorative purposes, it is an easy surface to print and typically has an exceptional look,” says Riley.
“The adhesion onto the can, especially after pasteurization, must remain strong and consistent. Therefore, the use of a coating before the inkjet process is applied is recommended to consistently achieve great print quality and ink adhesion after processing,” notes Edwards.
Riley admits that challenges involving single-use aluminum cans are mostly environmental. “The printed items need to survive perhaps water exposure in a cooler or sweating when moved from a cool to warmer environment.”
Inked In
UV ink is a popular choice for direct printing to aluminum cans. It is cost effective, safe, and durable.
UV printing offers a cost effective, fast, and easy way to produce short runs of a design or multiple designs using variable data, says Riley.
“These inks meet strict safety and compliance standards, offer low migration, and are safe for use for indirect food contact packaging,” comments Baginski.
An example of this is INX’s INXJet MDLM ink set, which offers regulatory compliance with low migration as a patented LED UV technology developed especially for aluminum cans.
UV-curable ink sets are durable. “They are designed to adhere well to a variety of surfaces, maintain long-term integrity throughout the product’s lifecycle, and are tested to withstand harsh conditions and handling with improved abrasion properties,” says Baginski.
Edwards points out that beyond UV, a number of ink sets are available for digitally printing onto aluminum cans. “The basic requirements relate to ink performance in the printing system, as well as its performance on the printed can. Another element to consider is the regulatory profile of the inks. In this application, the contents are likely to meet the can surface and customers will often drink out of the can. Therefore, it is important to ensure the ink components follow regulatory guidelines,” continues Edwards.
Extra Help
Sometimes ink can use a little help adhering to a surface or protected from damage after applied. It can’t do it all. Pretreatment and post-treatment methods assist. However, not any coating or process will do. When it comes to aluminum cans, there are certain things to consider like the fact that if it is a beverage container, people will be coming in contact with it via their mouth.
Baginski recommends pretreating any metal surface with a propane flame application prior to print. “A simple propane flame treatment before print will help to adjust the surface tension of the material into a friendly range, enhancing its receptivity to UV ink. The flame treatment will also remove any physical surface contaminants that could potentially disrupt the ink-to-substrate bond.”
“Pretreatment of the cans is critical for the final product performance,” comments Edwards. “A thin coating can be applied in an analog process to the surface to enhance the quality and adhesion characteristics. It is also possible to inkjet a precoat on the surface of the can to carry out the same requirements as pre-coated cans. However, this process is more expensive to implement based on the type and amount of ink required, and the need for an extra print station on the printing system to do it.”
Riley cautions that in regards to pretreatment it is important to “avoid any chemical promoter applications when dealing especially with vessels designed for drinking” and instead “rely on the adhesive properties of the ink.”
To ensure the graphic will last in conditions like water exposure, Riley suggests a varnish top coat.
However, Baginski says the luxury of using UV-curable ink as the decoration method is that no post-treatment is required. “The inks are cured during print, and a varnish clear coat can be layered on top of the CMYK for added durability.”
“Usually, the can printer has a channel to print a gloss varnish to finish the can, but it is recommended this ink should be regulatory friendly,” agrees Edwards.
Depending on the can, it’s also possible to provide an analog clear coating to achieve different finishes such as matte or satin, adds Edwards.
In the future, Edwards believes there will be more post-treatment methods available to enhance and differentiate the final product.
Recyclability Influence
Post use, aluminum cans are prime candidates for recycling. However, when digitally printed, the ink and/or a pre/post-treatment might need to be taken into consideration to allow for recycling.
Recycling entails “using high temperatures to melt the aluminum back to its original form and burn off any other materials. The use of labels applied to a can, either in the form of a paper label or a plastic sleeve, can complicate recycling and requires much more material to be burned off in the recycling process,” explains Edwards.
Directly printing onto the aluminum can be more sustainable, as less material is used or burned off during the recycling process, adds Edwards.
“When considering small, decorative additions to existing products and the amount of ink used is incredibly small on a per unit basis,” recyclability isn’t really affected, shares Riley.
Choosing UV-curable ink is an eco-friendly choice, attests Baginski. Its quick cure rates, minimal pollutant emissions, and reduced waste make them one step close to “greener” printing.
“The innovations with UV inks are maturing daily, with more sustainable and biodegradable options emerging in the industry constantly that can also play a part in determining the most sustainable digitally printed shelf life for any custom product,” says Baginski.
Cheers to Digital
Aluminum cans and bottles benefit from the capabilities of digital printing, especially as advancements in ink sets—particularly UV—make the process easier.
Nov2025, Industrial Print Magazine
