Abstract: This paper reported a new method for the formation of microfluidic chips through UV-curing microinjection molding. Because UV-curable materials were liquid at room temperature and the curing process is performed by chemical reactions, there were a number of differences between UV-curing microinjection molding and conventional microinjection molding. The results from injectionmolding experiments indicated that the bubbles appearing near the “cross” of micro channel as well as the whole surface of microfluidic chips were considered as a major defect in the forming process. Such a defect showed a negative effect on the use of microfluidic chips. Formation causes of this defect were analyzed through a visible experiment, and effects of injection pressure, vacuum, injection mode and illumination mode on the defect were investigated, and solutions for elimination of the defect were explored. The results indicated that the injection mode and illumination mode determined the formation of bubbles near the “cross” and on the whole surface of microfluidic chips, respectively. The defect could be eliminated completely by adopting suitable injection and illumination modes.

Key words: microfluidic chip, micro channel, UV-curing, microinjection molding, defect, visualization