ULTRASONIC SENSORS FOR ON-LINE MONITORING OF CASTINGS AND MOLDING PROCESSES AT ELEVATED TEMPERATURES

摘要

Ultrasonic sensors and associated methods for on-line monitoring ofmaterial properties for die casting, molding and extrusion processes atelevated temperatures are disclosed. The sensors include the use ofultrasonic waveguides embedded in the processing machines andpiezoelectric ultrasonic transducers. The sensors are operated in thereflection geometry m which one side access of the processing machines isrequired. The monitoring parameters are the flow front, gap development andtemperature of the materials being processed and filled in the cavities of thedie in casting processes and the mold in injection molding, and thetemperature and viscosity of the molten polymers in the polymer extrusionmachines. Piezoelectric ultrasonic transducers made of high Curietemperature materials, fabricated by sol-.gel techniques and directlydeposited on top of the ultrasonic waveguides or the external walls of theshotsleeve of the die caster, die of the die caster, mold of the injection moldingmachine or barrel of the extruder are also used.