By Olivia Cahoon
Aluminum composite material (ACM) features double- or single-sided painted aluminum, bonded to a solid polyethylene core for rigidity and a lightweight feel. Its flat surface and polyester coating makes ACM ideal for digital flatbed printing.
ACM’s flat surface promotes ink adhesion and supports image profiling during digital printing. Print service providers (PSPs) choose this rigid substrate for its outdoor durability and ability to be cut into custom shapes.
According to Marla Gomes, LEED AP, director, architectural building products and healthcare design, Nudo, ACM is ideal for digital printing because its even surface aids UV ink adhesion and eliminates printhead strikes. “ACM’s ability to be routed and returned or roll-formed after graphics are applied makes it a very flexible material,” she explains.
ACM is intended for long-term signage and is suitable for interior and exterior applications that require lightweight and durable fabricated material. Garrett Thompson, national sales manager, sign and digital print, Laminators Inc., shares that ACM is used for a variety of applications including architectural signage, billboards, canopies, construction, dimensional lettering, electrical LED and neon signs, fascia signs, fine art murals, mounted signs, multiple panel signs, point of purchase (POP) displays, real estate, and scoreboards. Available in a variety of colors, Thompson says ACM panels are the flattest panels in the industry making them ideal for digital print applications.
ACM signs are also water resistant and can be printed single- or double-sided with additional grooves and folds. Thompson recommends print providers clean ACM panels with 99 percent isopropyl alcohol prior to graphic application to ensure fine particles, smudges, or fingerprints don’t affect the print.
However, PSPs should note that not all ACM is designed for digital printing. “For example, polyvinylidene difluoride and high durable polyester coated ACM is intended for architectural exterior for building applications,” says Tony Lampariello, national rigid media product line manager, Agfa Graphics. ACM for signage and display graphics features a finished white polyester surface that allows for direct flatbed printing.
Coatings and Pricing
Because ACM is designed with a coated surface for digital printing, it usually doesn’t require additional coating. According to Gary DiFazio, director, marketing development, Piedmont Plastics, most UV and latex flatbed printers have little difficulty achieving good results on standard ACM sheets. However, understanding and planning for process requirements aids in successful printing.
DiFazio suggests PSPs consider if the printed ACM will be routed or fabricated and what the expected lifespan of the sign will be. “Knowing answers to questions such as these on the front end can help steer the end user to a product specifically designed for their need—be that additional ink adhesion, skin thickness, or weathering,” he continues.
ACM coated sheets generally promote ink adhesion and reduce flaking or chipping during routing, bending, and finishing. However, Duke Swank, national sales manager, Alumet Supply, recommends a print test for adhesion prior to a full production run. He suggests ACM with a polyester paint finish to ensure that ink adheres to the panel.
ACM prices vary based on coating, sheet size, and finishing. However, specialty colors like metallic inks and specialty finishes like a brushed look increase the price per sheet. According to Swank, on average, a three millimeter white ACM panel costs between $1.50 and $2 per square foot.
Sheet thickness also increases price per sheet. In fact, Lampariello believes prices mostly depend on the aluminum face thickness. He says ACM costs can range from $40 per sheet for thinner gauge faces to several hundred dollars per sheet for architectural grade ACM.
Challenges and Trends
Before digitally printing with ACM, PSPs should be aware of the printed product beyond color and size. It’s also important that PSPs have an idea of the aluminum skin thickness required for the print job.
Aluminum skins can be as thick as 0.12 inches. “However, for many digital printers, 0.005-inch aluminum skin thickness is sufficient because they’re not going to be subsequently fabricating the panel,” explains Swank.
During routing, DiFazio suggests PSPs provide extra care to ink loads and curing rates because uncured or excessive ink loads are more susceptible to chipping and flaking. “After routing, edges can become sharp and operators should handle material accordingly,” he explains.
To ensure ACM remains clean, Van George, sign territory manager, Graphic Solutions Group (GSG), believes PSPs should handle the clean substrate by the edges and wear cotton gloves to avoid contaminating the surface with fingerprints or skin oils that can interfere with ink adhesion.
George also recommends PSPs be aware of ghosting and chatter marks, which are present in low-quality, high-tac films that leave residue prior to printing. Ghosting occurs when a lighter duplicate image appears behind the original image due to excessive residue, humidity, or incorrect paper. Chatter marks are uneven ink applications that appear on the graphics. As a result of these challenges, George shares that most sign suppliers and manufacturers are moving towards digital coatings and easy-peel films.
Polyethylene cores can aid in the proliferation of flames, smoke, and fire ignition. To combat this challenge, Lampariello says ACM manufacturers of graphics grade products are introducing fire retardant cores. Fire retardant cores have been the general specification for architectural grade ACM for several years. “The graphics grade ACMs will soon see this specification across all products,” he assures.
Ben Branham, marketing manager, 3A Composites USA, believes ACM signage is popular due to its long-term usage—three to ten years. To ensure ACM signs can be displayed for several years, inside and outdoors, he explains that graphic designers and fabricators are turning to premium substrates that offer maximum lifespans.
Over 15 years ago 3A Composites introduced Dibond. Dibond consists of two pre-painted sheets of 0.012-inch aluminum bonded to a solid polyethylene core—making it half the weight of aluminum. “As the flattest panel on the market, durable Dibond offers a superior rigid surface for direct digital printing—it can also be routed and returned to add dimension or roll formed to deliver sweeping curves,” says Branham. Dibond is available in standard colors and a metal series including brushed silver, bronze, and copper. It’s available in sizes from 48×96 to 60×120 inches in thicknesses from two to four millimeters.
Released in March 2014, Agfa offers Duratex Alumaboard for indoor and outdoor use. Alumaboard is compatible with all digital and screen inks and is offered in sizes from 48×96 to 60×120 inches in thicknesses from three to six millimeters. Duratex Alumaboard features a five year external guarantee and is half the weight of traditional aluminum. It features a high-quality polyester paint finish and is capable of being drilled, cut, sheared, routed, and bent. Duratex Alumaboard is available in two-sided brush silver.
Alumet Supply’s Compbond ACM Brushed Silver was released in January 2017. It features two sides with specially formulated clear coat polyester paint for digital printing. Compbond is available in 48, 96, and 120 inches with three millimeter thickness. Its largest size, 48×120 inches, weighs 35 lbs. According to Swank, Compbond has an easily removable protective masking on both sides. It’s priced between $3 and $4 per square foot. “Alumet Supply uses an easily removable protective masking to ensure the surface is free from scratches, dust, or particles—a clean surface is ideal for those who digitally print on the panels,” recommends Swank.
GSG offers several ACM products including multi-panel ACM like Alupanel, Alupanel Lite, and Alupanel Digital. Alupanel offers an easy-peel film that is low-tac to remove in one clean, controlled sweep. “Our digital print panels have a specially formulated coating designed to help produce vibrant, color-fast prints,” says George. It’s composed of two 0.30 millimeter aluminum sheets with a polyethylene core. Alupanel is offered in sizes of 96×48 to 120×59 inches. It’s available in 18 colors and with brushed, metal, and PE paint finishes.
Laminators Inc. released Omega-Bond Economy in Spring 2017. It’s compatible with latex, UV, and solvent cured inks with little to no preparation work required. Omega-Bond Economy is available in sizes up to 48×96 inches with matte white or gloss white and three millimeter thickness. It weighs 16 lbs. per sheet and includes a five year panel and finish warranty. Omega-Bond Economy is intended for flat applications only.
Nudo offers PolyMetal—a recycled thermoplastic core sandwiched between two sheets of aluminum on one or two sides. Its recycled thermoplastic core is resistant to moisture and does not erode. PolyMetal is available in sizes of 4×8, 4×10, and 5×10 feet with thicknesses of three, four, and six millimeters. According to Gomes, PolyMetal ranges from $2 to $3 per square foot. It has a Class A fire rating and is available in solid, brushed, and polished mirror finishes.
Piedmont Plastics’ PSG AluPOLY was released in 2017. It’s available in standard sheet sizes from 48×96 to 60×120 inches and gauges from two to six millimeters. AluPOLY features anti-corrosion and primer treatments applied to both sides to make it resistant to water and most chemicals. Its polyester painted surface is compatible with most ink types. AluPOLY can be cut, fabricated, mounted, and installed. “Piedmont’s AluPOLY brand ACM is available in a digital grade that is specially designed for better ink adhesion,” adds DiFazio.
ACM is used for a variety of materials from billboards and canopies to construction signage and fine art murals. Before selecting ACM for digital printing, print providers should first ensure the panels are the correct thickness and have a polyester finish to guarantee ink adhesion.
Dec2017, Digital Output