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Measurement of Melt Temperature Profile inside the Nozzle of Injection Molding Machine by Integrated Thermocouple Sensor
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Murata, Yasuhiko / Yokoi, Hidetoshi / Ueda, Yukiharu
Measurement of melt temperature in the nozzle of an injection molding machine is very important in clarifying molding phenomena. As stated in the previous paper, the Integrated Thermocouple Sensor consisting of many thermocouples plated on a thin polyimide film was developed to measure the temperature distribution along the cavity depth.
This paper reports on the application of this sensor to measure cross-sectional melt temperature profiles in the nozzle of an injection molding machine. We investigated the effects of several plasticating conditions and screw channel depth at metering zone on the radial temperature distribution of the melt injected through the nozzle, and obtained the following results.
(1) We confirmed that the Integrated Thermocouple Sensor can be successfully utilized as a practical tool for the investigation of plasticating conditions and screw design.
(2) Even if screw channel depth at metering zone, screw feed stroke or revolution rate change, the melt temperature deviation in the nozzle channel is at a maximum in the center of the region between the channel center and the channel wall. As the screw channel depth at metering zone decreases or the feed stroke increases, the maximum deviation increases.
(3) As the melt residence time in the reservoir increases, the temperature deviation distribution ffattens.
(4) The temperature deviation distribution is closely related to how the melt accumulates in the reservoir during the charging process as well as the melt flow behavior in the nozzle channel during the injection process.
Key words: Injection molding / Measurement / Nozzle / Temperature distribution / Integrated Thermocouple Sensor