Digital Heat Transfers
by Matt Regan and Chris Blanken
Ask the Expert
With the continued trend toward shorter runs for all types of plastic molded products, there will be a demand for short-run decorating alternatives. Digital heat transfers provide an option for shorter run applications, with the added benefit of offering variable data on each plastic part. Plastics Decorating has asked two of the leading experts in the field of digital heat transfers to offer insight on frequently asked questions regarding the process.
Q: What are the advantages of digital heat transfers?
The first advantage that digital heat transfers provide over traditional decorating processes is cost-effective, full-color (cmyk+w) decoration for short-run, fast-turn projects. There are none of the traditional set-up requirements or costs, said Matt Regan, senior vice president for CDigital. Screens, blankets, dies and print stations for each color arent needed, so turn times are measured in days (often one), rather than weeks.
Since digital heat transfers are computer-generated and sent to a rip station, continued Chris Blanken, vice president of sales for Comdec, Inc., there is almost no press set-up time involved. Even if a new graphic is needed, digital heat transfers can be shipped within 48 hours.
The quicker turnaround times and decreased set-up costs lead to a major advantage for customers: lower per item costs. With traditional heat transfers, large quantities need to be purchased in order to make the order cost effective, explained Blanken. The same reasoning applies to pad printing and screen printing. Both pad printing and screen printing require plates or screens, plus registration time from color-to-color. But with digital heat transfers, a customer can purchase as little as one transfer.
With todays customized marketing and promotions, the ability to order small quantities provides another advantage. Any product being decorated with a digital transfer can have variable data included in each image in a run barcodes, photos, text or numbers making the ultimate short run of one possible and economical, Regan said.
Q: What applications work well with digital heat transfers?
Digital transfers started with the CD and DVD industry because of the need for lower-volume orders, explained Blanken. Other types of printing were cost-prohibitive in a very competitive market, and the same reasoning applies to many of our industries today. Holding large inventories of product or supplies is just not possible anymore. As a result, Blanken has seen digital heat transfers applied to promotional items such as pens, sports bottles and plastic cups. In addition, the glassware industry is moving toward digital heat transfers.
Regan concurred, Digital transfers can be used in almost any application using conventionally printed transfers. While there are many technologies available for decorating flat objects, transfers including digital ones are often the only solution for round, cylindrical or shaped products. Digital transfers bring this capability economically to short runs.
Q: What on-press challenges should be anticipated?
The major challenge, believes Regan, also is the major advantage. Being digital, an almost endless array of process colors can be built using the cmyk+w spectrum, he said. However, process color is not spot color and while these can be approximated, matching one or more spot colors in an art work can be a challenge.
Blanken acknowledged difficulties with toner-based color. There is a light lay-down of toner-based color and many darker-colored parts either reduce, change or make the graphic too transparent and unacceptable, Blanken explained. This requires an additional white layer in order to keep the transfer from being washed out or discolored. There are a few ways to solve this issue. The first is to have a white underlay printed on the part, and then the digital transfer is printed on the white underlay. According to Blanken, toner companies also are working on more opaque white toner to be used and the digital machine builders are working on additional white color attachments in order to improve the opacity.
Regan also conceded the generally acknowledged challenge of working with digital artifacts like banding and ghosting. While it is less an issue with the current state of the art, these can be further minimized in pre-press, said Regan. However, the truly successful digital transfer provider will eventually figure out how to get his client to design for digital and, as part of this effort, minimize the effect of these artifacts.
Q: How does applying digital heat transfers differ from the application process for traditional heat transfers?
The digital attribute should not, of itself, be a factor in the ease of application or use, said Regan. However, in CDigitals case, the toners, coatings and adhesion promoters used in its digital process result in a transfer that releases onto the product with less heat and less pressure than most conventional transfers. This means that less expensive equipment operating at greater speed can often be used by its customers.
Blanken agrees. Breaking away from the concept of more heat and pressure has been the toughest task for long-time heat transfer printers, he said. Less is best! It always is advisable to use just enough heat and pressure to apply the digital heat transfer. If too much pressure is used, there may be a hazing or ghosting of the release agent that is transferred to the part.
In addition, Blanken continued, too much heat can affect the toner and may darken the graphic. Since toner changes color with more heat being used, a vertical hot stamp press is not advised, but rather a standard roll-on or walking-shoe heat transfer machine is recommended.
Plastics Decorating thanks Matt Regan, senior vice president, CDigital Markets, LLC, and Chris Blanken, vice president of sales, Comdec, Inc., for their input. For more information, visit www.grafixx.com and www.comdecinc.com.