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A new pilot roll-to-roll (R2R) system has been installed at CondAlign by Emerson & Renwick, with an integral, dual lamp GEW LeoLED UV curing system which instantly cures the polymer coatings to fix the position of the aligned particles.
Broad range of productsCondAlign works with a range of products to customers from several market segments. This can be electrically conductive tapes and substrates, as well as thermal-interface materials for the electronics industry, biocompatible films to the healthcare sector, and membranes for gas and liquid separation. The application areas define the required material properties for each film, such as conductivity, elasticity, thickness, weight, softness, transparency, adhesiveness and biocompatibility.
Due to this diversity of applications, the film thicknesses can range from 5µm to 3mm. The heaviest films are often the thermally conductive type and contain ceramics or compounds such as boron nitride. This poses a challenge for the UV curing system and in order to ensure a consistent cure, the second UV LED lamphead has been designed to be reversible so that it can also irradiate from underneath the sample.
Ease of operationPhillip Mayhew is the lead engineer at CondAlign and works most closely with the new R2R system. He highlights the ease of operation of the machine, and how the UV LED curing system contributes to that simplicity: “I think the best one can say about the UV LED system is that it just does its job every time, without an issue. I can adjust anything I want on it and it just works exactly and perfectly every time. We’ve been using it for around nine months now and we are usually only operating at around 20% to 30% of the LED’s power capability. With the thickest, thermally conductive films we go up to around 60% power, so we still have plenty of room for manoeuvre.” He adds: “The line speed we can run at tends to be dictated by the time taken for the particles to align under the electrode plates, not the curing process.”
CondAlign also work with heat cured materials and have in the past used a mercury arc curing system for UV-cured polymers, but the heat generated on to the films was problematic and could cause wrinkling. Moving to LED has solved this issue, as minimal heat is generated by the LED modules during the curing process. UV-cured materials are preferable in all the applications where UV curing is an option, as Mayhew explains: “A typical heat-cured material requires five to ten minutes drying time at 150°C and our machine is around five metres in length, so as you can imagine our line speed would be prohibitively slow, never mind the heat generated and the costs incurred. Fortunately for us, LED provides the perfect solution. To give a comparison, with LED we can now hold the substrate temperature at a steady 25°C.”