集積熱電対センサによる型内樹脂内部の温度分布計測
Measurement of Melt Temperature Distribution along the Cavity Thickness Direction by Using Integrated Thermocouple Sensor
横井秀俊・村田泰彦・塚越 洋
Yokoi, Hidetoshi / Murata, Yasuhiko / Tsukakoshi, Hiroshi
The measurement of temperature distribution inside melt flow is of great importance in clarifying the molding phenomena and in developing the models for numerical simulations. Temperatures inside an injection mold can be measured using thermocouples, infrared-probe monitoring systems, ultrasonic wave or other methods. However, none of these methods enable the measurement of the temperature distribution along the cavity thickness direction in detail.
In this paper, the authors proposed a measurement method using an Integrated Thermocouple Sensor which consists of several thermocouples plated on a thin polyimide film. We examined the sensor's output voltage, response time and errors, as well as measured temperature profiles along the cavity thickness direction inside an injection mold, in order to confirm its applicability. The results obtained were as follows :
(1) The preliminary experiments showed that the lead wire longer than 5mm along the flow direction was necessary in order to avoid error due to thermal conduction.
(2) The experiments, carried out on general purpose polystyrene with various injection rates, resulted in reasonable temperature profiles across the cavity thickness that corresponded with the expected velocity profiles.
(3) During the filling process, a constant heat balancing layer appeared, and the temperature core layer inside the boundaries slightly increased, probably due to heat generation.
(4) During the compression process, a distinct temperature rise was observed between the skin and the core layers due to the compression melt motion toward the cavity wall.
Through these measurements, we confirmed the feasibility of the sensor proposed in this study.
Key words: Injection molding / Measurement / Injection mold / Temperature Distribution / Integrated Thermocouple Sensor