Thanks to its versatility, vinyl has always been a major player in the wide format printing and graphics industry. Those involved in these industries have most likely heard the terms cast vinyl and calendered vinyl. Although you may know the basic differences, it never hurts to get a refresh in order to help select the perfect media for your next project.
The most comprehensive explanation of this comparison is available here: http://www.signindustry.com/vinyl/articles/2005-07-01-Avery-CastVsCalendered.php3
Cast Vinyl: The term “cast” refers to the manufacturing process of this type of vinyl. Making a cast vinyl film is a lot like baking a cake. The vinyl begins with a “recipe” calling for a list of ingredients known as the formulation. These materials are added to a “bowl” or mixing churn in a predetermined order while mixing at specific speed and for a set amount of time to ensure a complete and consistent mixture. This liquid mixture, known as organosol, is then precisely metered or cast onto a moving web known as the casting sheet and is then processed through a series of ovens which allows for the evaporation of solvents. When the solvents are evaporated, a solid “film” is left behind. The film is then wound up in large-diameter rolls for subsequent adhesive coating. The casting sheet determines the texture of the film.
Advantages of cast films:
- Shrinkage is the lowest of all vinyl films because the “casting sheet,” not the film itself, is pulled through the machine. Since the film has not had any stress applied during the manufacturing process it does not try to resume or shrink back to its original form.
- Durability of cast films is generally higher than that of other vinyl films due to the manufacturing method and the raw materials used.
- Cast films can be made very thin which produces a conformable product that allows application over substrates with rivets, corrugations, and complex curves. Also, once applied, this low caliper makes the graphic less vulnerable to abrasive forces.
- Cast films also maintain their color and other properties better than other vinyl films. This results in better performance of pigments and UV absorbers.
- The manufacturing process of cast films makes it easy to run small productions of special colors to match. It is relatively easy to change color during production making color matching in small batches possible.
Calendered films: Like cast, calendered film also gets its name from the manufacturing process. The production of calendered film is similar to mixing and rolling out a pie dough. It is formulated with similar raw materials as cast. These ‘ingredients’ are mixed and later ‘kneaded’ in the extruder. Instead of grandma’s rolling pin, gigantic heated, steel rollers form the vinyl into a thin sheet. This process is called ‘calendering’.
Advantages of calendered films:
- Today’s calendered films are thinner, glossier, have better conformability and less shrinkage than calendered films made years ago.
- Greater production yields less cost
- Stiffer/thicker film equals easier handling
- Excellent performance on flat, simple and moderate curves
- Today’s calendered films have a greater variety of colors as well as a wide range of gloss levels.
- Shrinkage of polymeric or high grade calendered films can be as low as 2-3%
- Formulation of film increases resistance to abrasion