Elimination of Air Entrapment in Microstructures Glass Embossing Process Using Ultrasonic Vibration


  • Lanphuong Nguyen


Microstructure arrays have been recently applied widely in many precise optical systems. In order to improve the quality of microstructure arrays, it is necessary to avoid some defects including air entrapment which is usually occurs during micro replication process, such as injection molding, compression molding, and hot embossing. This study utilized ultrasonic vibration to support hot glass embossing process to eliminate defect due to air entrapment. Different hot embossing experiments were carried out with the glass samples 20 ´ 20 ´ 1 mm. Both traditional process and ultrasonic process were performed in nitrogen and vacuum environments. Experimental results show that air entrapment inside the microcavities became larger at higher temperature, which banned the glass to fill into the micro cavities. This phenomenon could be resolved completely with the assistance of ultrasonic vibration. Ultrasonic vibration with 35 kHz-frequency and 3 mm-amplitude of not only increase the glass material temperature but also eliminate air entrapment inside the micro cavities, which helped glass fill into the micro cavities more and more.