USING ULTRASONIC SENSORS FOR POWDER INJECTION-MOLDING

Previous research efforts concentrating on proof-of-principle studies have shown that ultrasonic nondestructive evaluation can be applied to the process monitoring of a powder-injection-molding system. This res earch has resulted in the successful detection of several injection-mo lding problems, such as flashing, shout shot, sticking, and sink marks . Past techniques, however, have required that the sensors be position ed so that the ultrasonic wave (bulk or guided) directly interacts wit h the defect. This article reports results from a technique that uses only one sensor for detecting several common injection-molding defects and does not require that the wave interact directly with the defect.