Title :
Real-time monitoring of fabrication process of microfluidic plastic devices using miniature ultrasonic sensors
Author :
Ono, Y. ; Cheng, C.-C. ; Kobayashi, M. ; Jen, C.K. ; Nardini, N. ; Gauthier, B.
Author_Institution :
Ind. Mater. Inst., Nat. Res. Council Canada, Boucherville, Que., Canada
Abstract :
Miniature ultrasonic sensors have been developed for real-time process monitoring of a microfluidic device fabrication using a polymer injection molding machine. A thick piezoelectric PZT film as an ultrasonic transducer was fabricated onto one end of 4 mm-diameter and 12 mm-long steel buffer rods using a sol gel spray technique. A signal-to-noise ratio of more than 30 dB for ultrasonic signals reflected at the probing end has been achieved. The center frequency and 6 dB bandwidth were 17 MHz and 14 MHz, respectively. The sensor can operate continuously at 200°C without ultrasonic couplant and cooling. Clear ultrasonic signals have been obtained during injection molding of a 1 mm- thick part having test patterns on its surface. Shrinkage of the molded part and the part detachment from the mold were successfully monitored. Surface imperfection of the molded parts due to the lack of the holding pressure was discussed.
Keywords :
injection moulding; microfluidics; piezoelectric transducers; process monitoring; shrinkage; sol-gel processing; ultrasonic measurement; ultrasonic transducers; 12 mm; 14 MHz; 17 MHz; 4 mm; PZT; PbZrO3TiO3; buffer rods; holding pressure; microfluidic device fabrication; microfluidic plastic devices; miniature ultrasonic sensors; molded part shrinkage; molded part surface imperfection; part mold detachment; polymer injection molding machine; real-time process monitoring; sol gel spray technique; thick piezoelectric PZT film; ultrasonic transducer; Condition monitoring; Fabrication; Injection molding; Microfluidics; Optical films; Piezoelectric films; Plastics; Polymers; Steel; Ultrasonic transducers;
Conference_Titel :
Ultrasonics Symposium, 2004 IEEE
Print_ISBN :
0-7803-8412-1
DOI :
10.1109/ULTSYM.2004.1417783