UV LED Curing Technology Goes MainstreamSnapshot of 2012

In the approx imately 10 years since ultra‐violet light‐emitting‐diode (UV LED) curing lamps appeared in the market, there have been significant technological advances in LED efficiency and curing lamp performance. The initial challenges have been met and overcome allowing rapid technology adoption across a broad array of industries.

UV LED BenefitsWhile one might argue with any specific cited advantage of the UV LED lamps, the total of the advantages of UV LED curing lamps is clear. They provide:

1. New capabilities to end‐users and machine‐builders by allowing tighter control over the curing process, especially on heat‐sensitive substrates.

2. Operating economics include reductions through energy efficiency, low maintenance and long lifetimes.

3. Environmental advantages by being ozone and mercury free as well as improving workplace safety.

Successful MarketsPrinting: First inkjet, then screen and now flexographic.Typical of many new technologies there needed to be a “starting‐point” where a specific benefit of the new technology “out‐weighs” the traditional method. UV inkjet applications (particularly on heat‐sensitive substrates) were an early and clear success for the UV LED curing lamps. Continued development has enabled the UV LED based curing lamp to be the best overall solution for UV inkjet curing applications. It’s very likely that within the next few years the vast majority of UV inkjet printers will utilize LED-curing lamps. Other ink‐curing applications where close proximity of the lamp to the substrate is easily achieved, such as UV flexographic printing and UV screen printing, will quickly follow. UV LED curing is also used or envisioned in curing of functional materials in many new applications in industrial inkjet.

Today, UV LEDs are finally taking their place as a mainstream curing technology. Rapid technological advancements being made in all areas of printing, from digital inkjet to f lexography and even offset, demonstrate the far-reaching potential and growing acceptance of UV LED

Bill Cortelyou, President and CEO, Phoseon Technology

feature

UV LEDs are finally taking their place as a mainstream curing technology. Rapid technological advancements being made in all areas of printing, from digital inkjet to flexography and even offset, demonstrate the far-reaching potential and growing acceptance of UV LED curing.

V i s i t S G I A a t S G I A . o r g S G I A J o u r n a l ■ M a r c h / A p r i l 2 0 1 3 | 1 1

curing. End users are increasingly asking equipment manufacturers for LED options, and the market‐leading vendors are responding. Confronted with such exciting and rapidly evolving technology, system builders and end users are closely monitoring the ever‐changing UV LED curing landscape.

Coatings: Wood flooring, cabinetry and advanced electronics.A significant number of coatings are cured worldwide today with UV LED sources in applications ranging from traditional materials such as f looring and cabinetry to advanced electronics. Material development and long‐term

performance testing will further open markets in the areas of automotive, electronics, residential and commercial construction materials.

Adhesives: Medical devices and consumer electronics.UV Adhesives are a great tool in modern assembly and manufacturing processes with UV LED electronic control and stability ensuring excellent results in a wide variety of UV LED adhesive applications from medical devices to the most advanced consumer electronics.

UV LED LampsUV LED lamps are available in air‐cooled and water‐cooled versions. Historically, the primary reason for water‐cooling was to efficiently cool the LEDs, so they could operate reliably at high power outputs. As air‐cooled technology and diode efficiency improved, air‐cooled UV LED lamps are now capable of curing materials at high speeds once reserved for water‐cooled systems. Assuming that the power requirement can be met with either air‐cooled or water‐cooled lamps there are a number of considerations when choosing between the two:

• Air‐Cooled: larger for most configurations, airflow — intake and exhaust, air filtering, cooling efficiency and lamp output dependent on the ambient.

• Water‐cooled: Requires water‐cooler and associated plumbing, typically small in relation to the power produced, no airflow considerations or air‐filtration required, precise output control based upon cooler/chiller control.

Obstacle

Chemistry

Performance

Price

Current Status

Initial UV LED lamps offered less power and capability compared to traditional curing methods. Today, UV LED lamps offer up to 16W/cm² peak irradiance surpassing some traditional lamp methods.

In 2002, very few types of ink were compatible with UV LED technology. In 2012, more than 20 inks and material vendors touted their support and ability to formulate for LED. New resins, monomers, oligomers and photo-initiators have been under development. Not only inks, but also coatings and adhesives are now widely available that are either specially formulated for LED or work with both LED and traditional mercury sources.

As with all new technologies, the initial prices are high. But with increased volumeand widespread acceptance, the”price-to-cure” with LED-based UV sources has decreased approximately five-fold in the past ten years and is now comparable withtraditional curing methods in order to bring many new capabilities and benefits.

Mercury Lamp

Wavelength (nm)

UVC

100-280nm

UVB

280-315nm

UVA

315-400nm

VISIBLE LIGHT

400-700nm

INFRARED

700-1800nm

365 LED

395 LED

Relat

ive In

tens

ity

UV LED vs. Mercury Spectral Distribution

1 2 | S G I A J o u r n a l ■ M a r c h / A p r i l 2 0 1 3 V i s i t S G I A a t S G I A . o r g

The FireJet™ is a high capability air cooled UV LED curing lamp aimed primarily at UV Inkjet wide-format systems and is capable of curing at the highest speeds for small, medium and grand format digital printing systems. It’s also ideal for many large single pass UV inkjet applications.

ControlA tremendous advantage of LED based lamps is that they are solid‐state devices and can be rapidly and precisely controlled. Delivery of a specific dose or intensity is easily achieved. With response times in the range of milliseconds, the lamp is typically turned‐off when energy isn’t needed, resulting in power savings and reduced stray light. UV LED lamps provide separate controllers, while other units have the control capability fully‐integrated within the lamp itself. This advanced control capability is being used today in all areas of curing to achieve unique matte or gloss finished in inks and other unique properties in coatings and adhesives previously unavailable.

Wavelength UV-AUV LED curing lamps are available today in wavelengths from 365 nanometer to 395 nanometers and higher. 395 nanometer lamps are the most popular due to their efficiency, power and price‐effectiveness. The technology and manufacturing methods of diodes become more challenging, as the wavelength gets shorter.

The eff iciency “penalty” for 385 nanometers, compared to 395 nanometers is about 10 percent and for 365 nanometers the diodes can be as much as 50 percent less efficient and more costly. All UV diodes have become more efficient over

time but the relative efficiency and cost improvements have favored the 395 nanometer diode due to its popularity. The 365 nanometer is sometimes used in specific applications where users are reluctant to change their formulations and the lower wavelength meets the requirements. Diode emission while labeled “monochromatic” is actually a relatively narrow distribution of wavelengths normally distributed around the “peak” with a practical spread of approximately 20 nanometers.

UV-B & UV-CMany times the question has been asked: Can a UV LED source be constructed as to replicate a mercury spectrum? While theoretically possible, the expense and lack of practical power render it impractical. Work is being done to produce more efficient and reliable diodes in the UV‐B (290 nanometers to 320 nanometers) and particularly UV‐C (220 nanometers to 290 nanometers) where UV‐C wavelengths can destroy pathogens such as viruses and bacteria.

The UV‐A diode will benefit from the technology learning curve of producing lower wavelengths rather than be supplanted by it. It’s expected that diodes in the lower wavelengths will find their place solving specific problems such as disinfection.

V i s i t S G I A a t S G I A . o r g S G I A J o u r n a l ■ M a r c h / A p r i l 2 0 1 3 | 1 3

In 2011, Empire Screen Printing, Inc. (Onalaska, Wisconsin) implemented break-through UV LED ink curing technology that provides economically sound and environmentally friendly sustainable print methods. This innovation was made possible by pulling together a key set of technology partners: Phoseon Technology, Nazdar Inks and Coatings, and Kammann USA. The new Kammann K61 ECO UV-LED press has thousands of Phoseon UV LED lights and uses specialized Nazdar LED curing ink. According to Empire, with this new capability, they can provide improved print performance while knowing their products are being produced in the most environmentally friendly method currently available in the screen printing industry.

Member Experience

Competition Validates Market GrowthThere are now a significant number of companies producing UV LED curing lamps worldwide, including many of the traditional mercury‐based lamp manufacturers. This competition provides for further market development, ensuring UV LED curing will continue to improve and benefit the end‐users of virtually all UV‐cured products.

The Future of UV LEDUV LED curing systems are entering their second decade with a strong footing. The original “top three” challenges of chemistry, price and performance have all made dramatic improvements and surpass the requirements of many applications and markets. Introductions of UV LED oriented materials such as photo initiators and resins will further the expansion of applications and support a strong alternative to mercury‐based curing.

So what does the future hold? Continued improvements in UV LED output, customizations of solutions for unique application requirements and an influx of vendors will surely grow the ecosystem. Additionally, new chemistries in adhesives and coatings will come to market allowing new industries in medical, electronic, and wood curing to transition towards LED.

Lastly, the European Commission periodically reviews RoHS exemptions. Currently, mercury lamps have been ‘grandfathered’ under RoHS due to the lack of alternatives. With UV LED enjoying rapid adoption and clearly becoming a viable alternative, some in the industry have started to wonder if the EC will remove or drastically tighten the grandfather clause, thereby putting future product development with mercury lamps in question. Forward thinking end‐users and OEMs clearly understand this potential and have began making transition plans to LED away from mercury. We expect that trend to increase even more in 2013 and beyond.

Bill Cortelyou joined Phoseon in 2007 as president and CEO, bringing 20 years of experience in semiconductor technology and capabilities. Prior to joining Phoseon, Cortelyou was an early investor in Phoseon as well as advising early stage technology companies. Previously, Cortelyou was vice president of operations at Integrated Device Technology covering semiconductor operations and manufacturing. Cortelyou holds a bachelors degree in physics from San Francisco State University.

1 4 | S G I A J o u r n a l ■ M a r c h / A p r i l 2 0 1 3 V i s i t S G I A a t S G I A . o r g

More support, more training, more tools. The mPower outputs brilliant digitally printed garments in seconds, with unparalleled color �delity and dependable performance. Every new AnaJet printer comes with free lifetime support and intensive hands-on training.

More customers. Get our Business in a Box! Every new AnaJet printer now includes a free license for InkSoft Flex, the best online design suite and order management solution.

More knowledge. Visit our site to see demos, educational webinars and customer testimonials. Learn why other garment decorators recommend AnaJet. Register for a free sample shirt.

Call or visit anajet.com/sgia.

Expect more