These inks are opening up new markets for digital wide-format printers by enabling the conversion of traditional analogue processes to more efficient short-run digital production.
“The technological developments that are driving development of new applications for UV-curable inkjet include VOC-free, or almost VOC-free, inks, low-migration inks that are safer for use with human contact, as well as rapid adoption of LED curing, which means targeted wavelength suitable for specific materials and adhesion requirements, and lastly flexible UV inks,” says Infotrends director of functional printing and packaging Ron Gilboa.
One such application is thermoforming, a manufacturing process whereby plastic is heated to a malleable temperature, vacuum formed in a mould, then cooled and trimmed to create a finished product. Firm such as EFI, Fujifilm and SwissQprint have all launched UV inkjet devices and inks in the past few years specifically aimed at deep-draw thermoforming applications.
The key to all of these products lies in the hyper flexible inks rather than the printers, although some technological advances in curing, particularly LED UV curing, have helped by widening the range of substrates that can be used. “LED UV curing uses significantly less energy and produces less heat, which in turn allows you to print on many more materials than we have in the past,” explains Gilboa.
While LED curing makes printing on heat-sensitive substrates easier, it is the inks that hold the key to survive the thermoforming process, which requires them to demonstrate a strong adhesion to the plastic and be able to stretch without cracking, flaking or losing colour density. The latest thermoforming UV inkjet inks from firms like Fujifilm and EFI can elongate by more than 1,000% on a wide range of materials, including PETG, acrylics, polycarbonates, polystyrenes and ABS, without suffering loss of hue or opacity. The inks also retain UV inkjet’s core properties of adhesion and scratch resistance, forming a hard, glossy surface post thermoforming.
At the same time the inks must retain a low enough viscosity to make them suitable for inkjet printing. This means that, although UV screen inks for thermoforming have existed for more than a decade, the creation of UV inkjet inks that could survive the same process required a new solution, as the screen inks typically used higher molecular weight resins and powder fillers that would have a negative impact on jetting reliability and could preclude jetting altogether. “To overcome this challenge, we use special low viscosity, high-performance polymers and optimum surface modifying chemistry to deliver the target levels of film performance, while maintaining excellent jetting reliability and stability in the inkjet printer,” says Mike Battersby, large-format marketing manager, Fujifilm Speciality Ink Systems.
Thermoforming is not new. It has long been used for both signage and industrial applications. The former includes the production of dimensional signs for POS displays, vending and gaming machine panels, while the latter can include everything from custom dashboards and bumpers to jacuzzis and boat hulls.
Traditionally, decorating these products would be done post-forming through the application of decals, self-adhesive labels or airbrushing. Following the advent of thermoforming screen inks in the 1990s, printing found a place in the thermoforming market. However, given the high makeready costs, screen printing is only viable with large order volumes, where the high upfront cost can be amortised across the order. EFI cites an example of a six-colour 600x1,200mm thermoformed screen-printed job that cost €5,000 (£3,500) in makeready waste and labour before a usable print came off the device.
Expanding portfolio
This makes thermoforming a prime target for analogue to digital conversion. However, Marco Boer, vice-president of IT Strategies points out that it’s still a pretty niche market. “We estimate about 30-35 companies in North America actually decorate industrial thermoform signage today and probably only a few own or use digital printing kit. Digital printing is potentially interesting to many of these companies because what is painted today could easily be printed in the future, saving time,” he says. “Digital printing would also allow for more customisation and photographic images, which is not possible with painting today.”
Niche as thermoform signage may be, the real prize – and the goal that has got so many wide-format printer and ink manufacturers interested in thermoforming – is in the industrial market, where there is the opportunity to sell digital hardware and inks to new clients outside the graphic arts. The first UK customer for Fujifilm’s Uvijet KV ink was Mimtec, a thermoforming company based in Portsmouth, which had never bought a press before investing in Fujifilm’s Acuity Advance Select printer in March this year. Meanwhile, Fujifilm’s Netherlands-based client Tismo Products has created an entirely new consumer market based on inkjet-printed thermoformed vehicle dashboards (see boxout).
“There are many other industrial thermoform markets that could benefit from digital print – particularly those offering parts related to decorative functions,” adds Boer. “Watch for the smaller, more innovative printer manufacturers to start uncovering the opportunities in these markets.”
Mimaki falls into this category with its 3M-developed LF-200 flexible ink, which doesn’t have the same elongation properties as the EFI or Fujifilm inks but is good enough for the right applications. Nottingham-based Instrument Repair Services is using the ink with its Mimaki UJF 3042FX A3 flatbed printer to print replacement speedometer dials on 500micron polycarbonate, which is then formed to a depth of about 5mm.
EFI business development director, inks, Mike Plier estimates that less than 1% of the addressable market is currently UV inkjet printed, adding: “The thermoform market is very large. It is one of those technologies that we walk right by. Every single one of us comes in contact with vacuum-formed products all day, everyday of our lives, from signage to displays to automotive and everything in between.”
Further potential
And remember, thermoforming is just one application that the manufacturers are now turning their attention to as they look to exploit the advances in both the inks and hardware. “All of this is coming out of the growth in UV printed wide-format,” says Gilboa. “We see compound annual growth rate between 2013-18 of about 9% growth in unit placement in the UV space to just shy of 9,000 units in 2018 and that excludes all of the smaller machines that do pad printing and the very industrial machines from firms like Wifag-Polytype. We’re also looking at combined hardware, ink, media and service revenues in 2018 that will top $2.5bn (£1.6bn) worldwide.”
The combination of low or no-VOCs, plus LED curing, plus flexible inks, plus low migration is clearly turning out to be a winning combination for UV inkjet manufacturers. “If you look at these four combined, the range of applications that could open to UV is almost limitless,” says Gilboa. “Add printheads that are higher resolution and more reliable and that enables inkjet to deliver a perfect storm where high-quality applications open up. Thermoforming is just one such application.”
Case study: Tismo Products
Based in the Netherlands, Tismo Products bought and installed an Acuity Advance Select printer from Fujifilm in March 2014 and then spent two months testing the manufacturer’s new Uvijet KV inks for a new venture, Super Click Covers, which aimed to capitalise on the demand for personalised, digitally printed thermoformed products in the form of car dash-board covers.
The company took its first orders for personalised Mini car dashboards in May 2014. By October it was producing a range of car model dashboards five days a week for customers across Europe, and had branched out into personalised cycle helmets and wheelie bins.
According to Fujfilm’s Mike Battersby, one of the interesting things about the business model is the fact that, despite also being a screen printer, Tismo backs up all the images with the Uvijet KV white on the Acuity Advance Select, rather than using a screen white.
He adds: “They could quite simply take the CMYK prints, back them up with a screen white and then send them off for forming. They prefer not to do that because the opacity of the KV white is good enough and they can then do the whole process on one machine and not have to stop the screen press in order to put the car dashboards through there.”
Tismo co-owner Hendré Vos says: “The Uvijet KV white ink produces a pure white opacity, which is fantastic. There is virtually no difference to using screen inks.”
He adds: “We are delighted with the market response – not just from end-users, but also from a number of designers and smaller printers across Europe who have opted to outsource digital thermoforming projects to us.”
