This article was published in the Feb/March 2020 issue of Performance Plastics Magazine (A publication of The International Association of Plastics Distribution)
Article by Christopher Airoldi
An eye-catching POP (point of purchase) display can often be the first step for luring in customers and making a sale. The world of acrylic sheet provides a number of options to accomplish this, such as digital prints, colors, textures, and lighting products, to really jazz up your display.
An intriguing choice for many is the use of digitally printable acrylic to display images and graphics. Digital printing offers the potential to place any image or graphic onto a piece of acrylic. While methods such as screen printing have been used for years, the option of using digital printing provides “the sky’s the limit” potential for what is placed on the acrylic. Where screen printing may be limited in designs, colors, and flexibility, digital prints allow the use of high-res photos, for example, to be printed in all of their full-color high-res detail for signs and displays. And flood-printing a clear sheet of printable acrylic can make all or part of the sheet appear to be any color that is needed, to highlight a product’s capabilities and reduce media stocking requirements.
As flatbed digital printing techniques have grown, users have long wanted to employ this method to print on acrylic. In particular, printing on the “second surface” (the back side) of acrylic can produce a stunning result – the image is viewed through the glossy or non-glare acrylic and provides a level of depth and richness to the image. Add in some polished edges to the acrylic, and the final digital print glistens. An added benefit of second-surface printing is that the printed image is protected from damage behind the acrylic, and also reaps the benefit of the UV protection provided by the acrylic.
Digitally printable acrylics can also be printed on via “first surface” printing. This can be useful when printing on colored sheet such as white and black.
However, one historical issue with digitally printing on acrylic is that most of these digital printers, or more specifically the inks that they use, don’t adhere well to standard acrylic. Some adhere a little bit, others adhere not at all. Fabrication shops may have experienced the horror of digitally printing on standard acrylic, feeling that they were successful, only to see the ink literally peeling off the acrylic during post-printing fabrication steps such as cutting, drilling, or routing. In other cases, the ink can literally be scraped off the acrylic with just a fingernail. Fortunately, digitally printable acrylic sheet is now available to solve this problem.
Obtaining and maintaining good adhesion of the ink to the acrylic is the number one feature of digitally printable acrylic sheet, and it’s where these products really hit a home run. It works by the presence of a special acrylic printable layer on one or both surfaces of the sheet. This special layer still maintains the good qualities of acrylic, such as high clarity and lack of color, while adding the substantial benefits of allowing it to be digitally printed and maintaining good ink adhesion.
When investigating the use of these acrylic digital printing sheets, there are several things to keep in mind. One of the biggest is to check for the flatness of the sheet, and to set the print head gap accordingly to avoid a print head strike. Having a print head strike the edge of bowed acrylic can lead to a costly repair. Print shops have been known to tape down the edges of bowed media to avoid this occurrence, but ideally they shouldn’t have to. Since acrylic will absorb moisture, especially during the hot and humid summer months, it is important to keep digitally printable acrylic stock covered in its polyethylene wrapping to minimize this. Special packaging is also available to help maintain the quality of printable acrylic.
Also important to acknowledge is the fact that static electricity can affect the printed result. As a minimum, a static-reducing wand should be waved slightly above the acrylic after peeling the poly masking but before printing. The use of low-static poly masking in some cases can help with this situation.
Aside from the digital printing grade of acrylic, there are a number of other acrylic sheet products that will help your POP display pop. A rainbow of colors is available, and some are transparent while others are translucent or opaque. Mirrorized acrylic sheet is also available to give your display a sparkling appearance. There are textured acrylic sheets that can provide some softness and an alternative look. Textured sheets that have a satin finish can even hide fingerprints, making it easier to keep your display looking good. Newer to the scene are clear acrylics with an anti-fingerprint or easy-clean coating that again help to keep your displays from showing the day’s wear and tear.
Acrylic sheet is a natural choice to use in lighting applications. In some cases, the high clarity and light transmission of acrylic is ideal. In other cases, the acrylic can be manufactured with surface textures or encapsulated diffusing agents to create other lighting effects. One particular type of acrylic sheet is designed to pipe light from the face of the acrylic by edge lighting with LEDs. The value of this type of product is that the resulting sign or display can be very thin, less than an inch, instead of having a traditional back-lit sign or display of several inches. Illuminated POP displays can then be made by placing one of these edge-lighting panels behind a piece of digitally printed acrylic, for a real eye-opening display. It’s like getting the best of two worlds – sharp digitally printed acrylic signs or displays with very thin illuminating panels behind them.
If you’re in the market for a digital printer, there are a great number of them to pick from. Some are pure flatbed printers, and others are hybrids that can also be used in a roll-to-roll configuration. The design intention of printers can vary too – some are more suited to high-volume sign printing, for example, while others are more capable when printing high-resolution photographs. Two big factors that affect the price of most printers is the size that they are capable of printing and the throughput of the printer (often reported as the number of 4’x8’ “boards per hour”). Printers are also capable of a wide range of resolutions or quality settings to fit your needs. Flatbed printers generally use UV light to cure the ink after it is applied to the sheet (the UV energy can be provided by bulbs or LEDs) – this allows the prints to be completely “dry” immediately after they’re printed.
It can be a daunting task to select a printer, but there are ways to make it easier. Attend a trade show that is either dedicated to digital printing or have a large representation by companies that make digital printers. Two examples of these shows are the ISA Sign Expo, typically held in the spring (in Orlando in 2020), and the Printing United show, typically held in the fall (in Atlanta in 2020). These shows present the opportunity to view a great number of printers “in action”, talk to the people that make them, and to get some samples. Your acrylic sheet manufacturer should also be able to provide you with some ideas for selecting a digital printer. In addition, most major printer manufacturers have demo labs in the U.S. that are available for your visit to see their printers demonstrated right in front of you. Combine that with the cost information for each one and you’re well on your way to selecting the printer that works best for you – and you’ll be printing beautiful POP displays on digitally printable acrylic before you know it.