By Olivia Cahoon
Part 1 of 2
While thermoforming is often used for signage, it’s also found in industrial markets such as automotive, construction, medical, and plastic. Applications include automotive interiors, bath fixtures, as well as prototypes.
UV ink sets for thermoforming should feature adequate adhesion, flexibility, and durability to perform efficiently. For further success manufacturers may purchase a bundled ink and printer solution that guarantees compatibility.
Thermoforming in Manufacturing
A variety of manufacturers and industrial industries use thermoforming practices with digital print technology. It’s often found in traditional sign and display markets, packaging, plastic industries, and three-dimensional (3D) models and prototypes.
“Digital printing/thermoforming offers a shorter setup time compared to screenprinting, higher quality, near photographic images, and allows prototype work to be fast and economical,” shares Ramona Serafino, associate product marketing manager, graphic systems division, Fujifilm North America Corporation.
New applications are emerging as thermoforming replaces the more traditional screenprint market. For instance, automotive interiors, slot machines, bath fixtures, and even suitcases. According to Deborah Hutcheson, director marketing, Agfa Graphics, thermoforming paired with digital printing is more cost effective for short runs, custom products, and it also allows for versioning.
Historically, thermoforming was limited to mostly single-color applications. However, with improvements in ink and software, thermoforming is now more relevant with printed graphics. Michael Maxwell, senior manager, Mimaki USA, Inc., shares, “with these technological advancements, thermoforming processes are combined with printed graphics to create a variety of unique products, such as custom dimensional objects, displays, and larger signage.”
Ink Sets Are Prepared
To be successful in manufacturing environments, UV ink sets for thermoforming should offer adhesion, flexibility, durability, and curing.
Adhesion
When working with UV ink, adhesion is typically a concern. The thermoforming process uses high temperatures and challenging materials that pose a risk to adhesion.
Because of this process, most end users digitally printing and thermoforming not only invest in the necessary equipment, but also the materials and material testing that best supports this process, shares Jay Roberts, product manager, UV printers, Roland DGA Corporation.
Using the proper materials helps ensure high quality and optimum adhesion. “Most end users who thermoform print to KYDEX, polycarbonate, polyetherimide, and PETG,” adds Roberts.
According to Mike Kyritsi, U.S. president, swissQprint, adhesion from UV ink is also excellent for other media such as ACM, acrylic, anodized aluminum, glass, polypropylene, PVC, and vinyl.
However, Terry Amerine, VP, sales and marketing, Polymeric Group, thinks adhesion isn’t much of a concern. He believes most thermoforming materials are similar to those used in other print applications—therefore, ink adhesion is not an issue. “The heat of the thermoforming process actually aids in achieving adhesion.”
Flexibility
Flexibility is integral to the thermoforming process, which requires substrates and ink that bend and stretch easily in a controlled and predictable manner.
To determine the proper flexibility, UV ink sets require specific chemistry to achieve extreme draws and ink elongation. “The demands for flexibility for thermoforming applications are quite extreme but ink manufacturers have been able to meet them for several years,” says Amerine.
According to Kyritsi, UV ink sets should be flexible by up to 500 percent ink draw and stretch when heated to 180 degrees Celsius.
In cases where temperature is known to flunctuate, long-term flexibility is needed to ensure the prints’ performance overtime, shares Phil Jackman, global product manager, digital, Sun Chemical.
The extent of the stretch should also be considered. “Inks with more than 500 percent elongation are possible, but they tend to be too soft for many surface print applications, and therefore are not particularly suitable for applications other than reverse print thermoforming,” explains Jackman.
If the printer’s entire output will be thermoformed, he believes a dedicated ink and dedicated machine is preferred.
Durability
Thermoformed products are often used outdoors or in industrial environments with challenging conditions. To preserve the print, it’s important that ink sets are durable enough to protect against weathering and chemicals.
UV ink for thermoforming likely requires a functional or protective topcoat depending on the application’s durability requirements, weather, and chemical resistance. According to Amerine, this is a common practice in the industry and usually involves a roller coat, typically UV-curable as well.
Pedro J. Martinez, CEO, Afford Inks, adds, “the inks are formulated with lightfast pigments, which are eight in the wool scale.” However, due to the particular curing conditions, outdoor exposure should be tested.
Other Properties
Additional characteristics for UV ink sets are driven by the end application.
For example, Amerine says final products used outdoors in an industrial environment require ink that exhibits UV lightfastness, resistance to chemicals used in the production process, and scratch and impact resistance.
Compared to traditional UV printing, LED curable inks provide a better solution for thermoforming since the process does not generate as much heat, shares Maxwell. With lower heat, there is less concern of distorting the image or material resulting in finer detail and better results.
Do Your Homework
Before investing in a UV ink set for thermoforming, manufacturers should consider future growth capabilities and perform market research.
Because thermoforming is a unique and specialized niche, it’s important that manufacturers do their due diligence and research reliable market information before purchasing. Roberts believes this includes investigating not only UV LED printer investments, but ink as well.
Customers should also consider growth opportunity. Scalability is key in this type of purchase. According to Maxwell, purchasing a printer with enough bed size to accommodate growth, or allocating enough space in the production facility for multiple machines is key to long-term success.
Amerine suggests manufacturers fully understand the end use requirements of the application. “They need to determine the capability of the printer and ink with their internal processes, the production flow, and how the digital system will be incorporated into it.”
“UV LED inks for thermoforming will offer a unique opportunity to differentiate against the competition,” adds Martinez. However, due to the nature of the ink, it should be limited for applications where extreme scratch resistance is needed. “Usually, their chemical resistance is also less than that achieved with regular UV LED inks.”
Bundling Purchases
When selecting a UV LED ink, manufacturers typically bundle the purchase with the printer to ensure the thermoforming process is as successful as possible. However, a variety of users do not bundle purchases.
Manufacturers bundle printer and ink purchases to guarantee the thermoforming and printing process is efficient. “The most efficient systems are those where all the components of the system—ink, printheads, engine, software—are optimized to work together,” recommends Hutcheson. Press manufacturers that also control ink development can fine tune the ink and system components to ensure the highest quality output across a range of applications.
When working with a press and ink manufacturer, all of the available options for printing and thermoforming should be presented so the customer receives the best setup for their operation. Kyritsi says this includes deciding through testing which ink set best achieves the client’s needs.
UV & Thermoforming
Manufacturers increasingly use thermoforming and digital printing technology for products from bath fixtures to 3D prototypes. Flexibility, adhesion, and durability are key players in UV ink sets that help guarantee the thermoforming process is successful.
The second part in this series features a roundup of available UV ink sets for thermoforming.
Click here to read part two of this exclusive online series, Flexible Inks.
Oct2019, Industrial Print Magazine