Measurement of Melt Temperature Distribution along the Cavity Thickness Direction by Using Integrated Thermocouple Sensor

Following the previous study, the resin temperature distribution through the thickness of a cavity was directly measured using an integrated thermocouple sensor. The following conditions were controlled in this study: (1) resin temperature and mold temperature, (2) surface roughness conditions and (3) cavity thickness.The conclusions of this present study are the following:(1) When the (incoming) resin temperature was raised at a fixed mold temperature, no peak was observed in the temperature distribution. However, when the mold temperature was appropriately adjusted at constant (incoming) resin temperature, a peak in the temperature distribution could develop. This peak was relatively insensitive to changes in the mold temperature.(2) Adjustment of the cavity surface properties from a satin surface finish to a mirror finish did not change the location of the temperature peak, but did alter the temperature distribution in the region between the temperature peak and the cavity wall.(3) When the cavity thickness was changed, the temperature peak was found to occur at the same distance from the cavity wall. It was also confirmed that the temperature distribution was relatively flat from the peak to the cavity wall.(4) The conclusions from the previous studies and the above results clarify that the following five factors cause the temperature peak phenomenon: (1) the crystallization temperature “Tc” or viscosity properties near the glass transition point “Tg”, (2) latent heat, (3) thermal conductivity, (4) resin temperature and (5) cavity thickness.