Measuring Methods for Molding Process of Plastics by Using Ultrasonic Wave

Research Project

Project/Area Number	62850025
Research Category	Grant-in-Aid for Developmental Scientific Research
Allocation Type	Single-year Grants
Research Field	機械工作
Research Institution	Tokyo University of Agriculture and Technology
Principal Investigator	NISIWAKI Nobuhiko Tokyo University of Agriculture and Technology,Professor, 工学部, 教授 (90016626)
Co-Investigator(Kenkyū-buntansha)	TSUTSUMI Masaomi Tokyo University of Agriculture and Technology,Professor, 工学部, 教授 (90108217)
Project Period (FY)	1987 – 1988
Project Status	Completed (Fiscal Year 1988)
Budget Amount *help	¥16,800,000 (Direct Cost: ¥16,800,000) Fiscal Year 1988: ¥7,000,000 (Direct Cost: ¥7,000,000) Fiscal Year 1987: ¥9,800,000 (Direct Cost: ¥9,800,000)
Keywords	Molding Process / Monitoring System / Ultrasonic / Pulse Echo Technique / Metal Mold / Filling Process
Research Abstract	Injection molding is one of the processing methods of plastics. Recently, it has been important to improve the accuracy and efficiency. In this process, making a good product is not easy, because there are so many influencing conditions and the molding process of plastics has not been clarified yet. In order to clarify it, many studies have been doing, for example, it has been done to measure temperature and pressure of plastics in the cavity by using various sensors and to analyze by using computer. Methods of verifying the measured value have, however apparently not been established to date. It is uncertain whether practical molding process and these experimental results will agree or not. It have become the largest problem to improve it. Therefore, this study aims to clarify molding process in the cavity by using ultrasonic wave. Some fundamental experiments have carried out by using simple models of metal mold and measuring methods based upon the pules echo technique. From these experimental results, in the molding process, a traveling time of ultrasonic wave through plastics decreases with the decreasing temperature and increasing pressure of plastics. It is clear that the temperature distribution can be estimated by using these results and echoes from the interface between solid and liquid phase of plastics in the cavity. On the other, plastics perfectly charged in the cavity can be detected by observing the secondary echo from its surface.