Have you ever wondered how the labels get printed on cans of soda or craft beer? Chances are, the product that you’re holding in your hand was printed using flexographic technology.
While the flexographic printing process remains largely the same regardless of your substrate (material being printed on), there are special considerations that need to be made in the planning and production phases when printing on cans.
Depending on the specific substrate and graphics, your printer will dictate whether plates, sleeves, or a mixture of both will be used during printing. This decision affects the image carrier service - the company that is creating the actual sleeves and plates that go into your press.
But, getting to the basics, how do they print on aluminum cans again?
Printing on an aluminum substrate (like most soda and craft beer cans) starts off the same way as any other substrate: a graphic designer or art house creates the logo, text, or artwork that will be printed. Next, a print house will be contracted for the printing job.
Typically, aluminum can printing jobs are done through labeling, not printing directly onto the substrate. Label printing is the bread and butter of flexographic printing and follows the process discussed above.
After the printing house receives the graphic (called a 1-up file) they contract an image carrier service to create the engraved portions of the press that transfer the ink.
Once the image carriers are created and loaded onto the press, the aluminum substrate or can is fed into the machine, then specialized rollers carry it through the machine and apply the different levels of ink. These layers typically include a base coat applied by a continuous cylinder, and logos, nutritional facts, and more printed using plates. After each layer of ink has been applied, the can then moves through a drying/curing process which adheres the ink onto the substrate.
If you don’t know what image carrier services are, you’re not alone. An image carrier is a sleeve, plate, or cylinder, that passes over top of and transfers ink to the substrate. The companies that make those components are called “image carrier services” and they play an integral role in flexographic printing operations. Your image carrier service will use the 1-up file to engrave a cylinder or plate (or both) to be used in your printing operation.
When it comes to aluminum can printing, special considerations need to be made for “stay-away” lines. A stay-away line accounts for the minuscule movement the ink may encounter when moving from the printing section to the drying section.
Because aluminum is a non-porous material, the ink won’t absorb like on other substrates. Generally, UV curable ink is commonly used to print on aluminum because water or solvent-based inks can take too long to dry.
Stay-away lines play a vital part in preventing color overlapping, smearing, and poor image quality.
State-of-the-art image carrier services use elastomer blend sleeves to cut costs and production time, ultimately cutting the cost and time your printing job will take. Learn more about elastomer blends and how they can up the efficiency of your next printing job here:
Aluminum can printing follows most flexographic printing operations and most usually involve both cylinders and plates.
Take a popular lemon-lime soda, sleeves provide a continuous, 360-degree engraved printing/ink-transferring surface, so the green background and any base-layer graphics will be done using a continuous-print cylinder. Plates are then created to print the logo, nutritional information, and any other graphics not added from the initial cylinder(s).
It’s clear that image carrier services play an integral part in any flexographic printing operation. Therefore it’s imperative to choose one with proven flexo printing experience. Luminite has been servicing the flexographic industry since 1926 and seeks to provide the highest quality print solutions. Contact us today to check our full capabilities and to schedule your consultation.