Conductive Inkjet Technology (CIT) made headlines recently when they hosted an open house at their Cambridge, UK facility, as part of the IDTechex RFID Europe Conference, and demonstrated their latest Metal Jet 6000 system. I-Connect 007's Pete Starkey visited CEO Chris Malley to learn more of the story behind the news.

007: I first saw your equipment at Productronica 2005 and was really impressed with the concept. I remember a fully-integrated roll-to-roll machine with on-line inkjet printing and curing of a catalytic ink, feeding directly into an electroless copper process: blank polyester film going in one end of the machine, metallised circuits coming out the other end. Can you explain what development has taken place over the last three years?

CM: Our exhibit at Productronica 2005 provoked a huge amount of interest. The machine was a good technology demonstrator, but some of the details weren't right and, quite honestly, the system was a long way from production reality. We have completely re-engineered it in the meantime, and also made significant changes to the ink formulation. We are now able to realise all of our original objectives in a robust industrialised process that is precise and repeatable and has many innovative features.

007: Before we get into the details, can you tell us a little about how CIT originated?

CM: CIT was founded as a joint venture between Carclo plc, leaders in technical plastics and precision products, and Xennia Technology Ltd, an independent inkjet research and development company, who had been working together on a process for inkjet printing of conductive features on mouldings. Recognising the limitations of jetting nanoparticle inks, they explored alternatives and came up with the two-stage principle upon which our present technology is based. A lot of knowledge had been accumulated, but the original project didn't go ahead.

CIT was formed to hold the IPR and develop a strategy for its commercial exploitation. Originally located in Royston, we moved here to Cambridge in 2006. About 12 months ago, Carclo bought-out Xennia's holding and we are now a 100% Carclo company. We had targeted the rapidly-growing RFID market and did a lot of characterisation, qualification and reliability testing with the market leaders. They confirmed that antennae manufactured using our technology had ideal characteristics for UHF and microwave RFID applications, with efficiencies better than could be achieved with silver ink. And the costs were very favourable as well.

Our primary business model was to supply our patented UV curable catalyst inks directly to customers under licence, and for the processing equipment we originally partnered with Xennia, to develop a roll-to-roll print engine, and with Preco, to develop a web-handling system. The concept machine you saw in 2005 was the result of those partnerships.

007: How did you move on from there?

CM: As I said earlier, the concept was good, but some of the details weren't right. In truth, we had to go back to the drawing board. We knew what we were trying to accomplish, but perhaps hadn't realised just how difficult it is to achieve accurate digital printing on a roll-to-roll web, particularly when you are using staggered print heads. The slightest angular deviation in web direction can put the image out by a couple of pixels--you might get away with that in graphics, but it could result in a fatal defect in an electronic circuit.

We evaluated lots of specialist web transport manufacturers and found that Alpha Converting, based in Bedfordshire, UK, could meet our specification. Similarly, we found that Inca Digital here in Cambridge, now part of Dainippon Screen, could provide the right print engine for the job. It's an industry-proven design based on standard Spectra heads, customised to our requirements, with automatic cleaning and maintenance. The machine you see now also has onboard UV and IR curing, and full on-the-fly optical inspection. It can handle a roll 300 mm wide and print up to 260 mm across the web at resolutions of 300 x 300 or 300 x 600 dpi. We typically run at 30 metres per minute, although the line is capable of speeds up to 80 metres per minute.

007: I see that you have separated the plating module from the printer.

Figure 1: CIT's printing unit (in the foreground) and the plating unit.

CM: Yes. It seemed a nice idea originally to have the whole system contained in one unit but, functionally, the processes are so different and work at such different speeds that it makes good sense to separate them. The output of one printer could easily support three plating modules. The system as it stands now gives us a lot of flexibility in batch sizes, materials and plating thicknesses.