Screen-Printing and an initial investigation into the development of an Environmentally Friendly Printed Circuit Board

摘要

This paper investigates an additive screen-printing process with regard to specific evaluation criteria to identify whether this process offers a viable alternative to current subtractive methods of PCB manufacture. A number of key process parameters when screen-printing have been identified. Snap-off, squeegee hardness, squeegee pressure and standing time affect the quality and integrity of the printed pattern. A 2~4 factorial design of experiments was employed to investigate these parameters and through experimentation it was established that a snap-off of 1 mm, a squeegee hardness of 70 shore, a pressure 0.41 bar and 0 s standing time resulted in accurate and completed prints. It was observed that multiple passes of the squeegee resulted in a greater deposition of ink on the substrate thereby reducing the resistance of the final printed track. It was further identified that when conductive ink samples are cured in a convection oven the resistance recorded was comparable with an etched copper datum board. It can be concluded therefore that a screen-printed conductive ink pattern, when printed on a degradable substrate with multiple passes of a squeegee and cured in a convection oven can offer a viable alternative to current printed circuit boards.