Printed electronics can enable very large numbers of new microelectronic products in a cost-efficient way, such as RFID tags and smart objects. Soluble semi-conducting materials are necessary to enable a mass production process on an extremely thin, flexible film.Results of multi-bit circuits and RFID transponder with poly-(3-hexylthiophene) as p-type semiconductor fabricated completely from roll-to-roll in mass production processes are shown. Process inspection and optimization is a key to successful development. A testing machine capable of electrically measuring kilometers of printed electronics is presented. A yield of 98.5% working polymer field effect transistors within specifications was obtained.