The February 2011 cover of Canvas magazine has brought attention to the potential for printed electronics. The cover is a collaboration between a range of industry leaders, brought together by Cal Poly State University.
Si-Cal medical products on press
"Si-Cal has been in business for 40 years as a roll-to-roll screen printer manufacturing a product called a heat transfer," says Jaye Tyler, president and CEO. "A heat transfer used to permanently mark and identify many types of products, such as the air bag warning labels on automotive sun visors (fabric), lots of plastic parts, apparel, and even metal.
"Si-Cal entered the PE market in 2005 when we printed RFID antennas and a consumer electronic 'array' for companies that wanted rolls rather than sheets to allow for improved downstream electronics assembly, lamination and diecutting," Tyler adds.
Heat transfer labels
An industry leader in the heat transfer segment, Si-Cal runs 12 presses, including its high-end A&M Kinzel Maschinenbau press. The company is adding a second Kinzel press in September. Si-Cal has found its sweet spot in the roll-to-roll field.
Heat transfer decals need to be long lasting and weather resistant, and must adhere to a wide range of substrates and materials. Si-Cal's labels can be found on major brands, including those of Procter & Gamble and Black & Decker. Each of these has its own stringent requirements, and to accommodate those needs Si-Cal manufactures its own solvent-based inks and has an unusually large number of PhD chemists on its R&D staff.
"Airbag labels are required to have seven years of UV resistance and must adhere to different types of fabrics," Tyler says. "They must also withstand climates ranging from freezing to the tropics."
Conductivity is a key requirement in PE systems. Si-Cal's high-speed, tight tolerance, roll-to-roll screen printing process can create comparatively thick deposition layers, some over 2 mils, that result in tough, reliable and long-lasting products. The company can print on both thick and very thin (down to 1 mil/25 micron) film and paper substrates, cured with either UV light or thermal processes.
A Si-Cal automotive visor application
"Si-Cal is one of the very few with the capability to supply printed antenna and medical test strip arrays with tight image to image alignment/repeat distance and skew tolerances," notes Richard Morris of Saxby Business Development, who represents Si-Cal.
With this knowledge and experience, Si-Cal was the ideal choice when NTERA looked for printers to take on the challenges faced in the Canvas magazine project. "Si-Cal was brought in to the Canvas project by NTERA, whom we have worked with in the past on other projects to print their NanoChromic ink system," Tyler said. "The display on the magazine cover was probably the most complex PE display ever attempted, as it required multiple layers of NTERA inks and graphic inks, manufactured on a very tight schedule with partner companies both up and down stream from the functional printing in Europe and both US coasts. With so many functional ink layers, color matching and layer opacity requirements the build was highly complex, with design and development compressed into a four-month window."
As the use of printed electronics spreads, customers are coming up with new applications and product designs each day. Si-Cal has the ability to help design the end device or sub assembly as well as run prototype batches from a few hundred to thousands of units onto high volume production.
"On several occasions, we have been brought in to projects where many of the critical requirements – exact type of ink, ink deposit thickness, drying/curing profiles – have not been provided because much of this is being developed," Tyler said. "Si-Cal then relies on its 40 years of web screen printing experience to figure out these requirements (the average tenure of our 23 person staff is 24 years). Si-Cal does not outsource any part of the manufacturing process, so I think that gives us a distinct advantage as we make our own screens and also make our own graphic inks, so this allows us good flexibility on the fly when it is needed. We also pride ourselves in a total 'can do' environment and have many individuals who simply roll up their sleeves to figure out technical and manufacturing issues.
Si-Cal RFID on press
"Normally it takes two to three years for medical, military and even smart packaging printed electronics programs to mature," Morris adds. "Printers require patience, attention to detail through the prototyping phases/scale up and a volume manufacturing organization. Si-Cal has been manufacturing millions of thermal transfer labels each year for decades and brings their unique skills to the emerging printed electronics industry. Success and experience build on one another, from RFID antennas to flexible displays, to medical devices and beyond."
Tyler says that Si-Cal is expanding its capacity to meet the needs of the PE industry. "We are very optimistic for the continued development of the PE industry, and in fact are doubling our capacity by September 2011 with the addition of another specially designed press."