Micromolding of polymer nanocomposites diagnosed by ultrasound

Miniaturized ultrasonic sensors, fabricated onto the mold insert of a micromolding (MM) machine, have been applied for real-time diagnosis of micromolding of polymer nanocomposites, nylon66 with polyhedral oligomeric silsesquioxanes (POSS) as nanofiller. The process dynamics, such as melt arrival, mold open and part detachment, were successfully monitored during molding. Ultrasound was capable of measuring peak injection pressure and material solidification process. In the pressure range between 50 and 150 MPa, the ultrasonic velocity linearly increased with a changing ratio of 2.6(m/s)IMPa. It was also found that concentration of the nanofiller (POSS) could be evaluated by using ultrasonic velocity measurement. In the concentration range of POSS between 0% and 8% the ultrasonic velocity linearly decreased with a changing ratio of 7.38(mls)/%. The presented ultrasonic sensors and technique optimize the micromolding of nanocomposites, and improve the part quality and process efficiency by controlling mold cycle time.