| Summary: | 碩士 === 國立臺北科技大學 === 製造科技研究所 === 103 === This thesis is to study the melt flow fluidity of hot runner mold under the different gate size and nozzle type. The mold is designed a single hot runner system. Two gate sizes are 1mm and 1.5mm. Two types of nozzle shape are the trumpet type and straight type. Spiral flow test method was used to evaluate the melt flow fluidity. The melt flow length was calculated when the melt move a maximum distance in the cavity. Test material are: (1)crystal plastic, PP, mold temperature is 50˚C, melt temperature is 220˚C. (2)amorphous plastic, PC and PC +15% GF, mold temperature is 70˚C, melt temperature is 270˚C. For the PP material, results show the best fluidity obtained when the gate diameter 1.0 mm and straight type used. For the PC material, the best fluidity is got under the gate diameter 1.5 mm and trumpet gate. For the PC+15%GF, gate diameter 1.0 mm and trumpet gate had the best fluidity. the gate diameter 1.5 mm and straight type is the worst. The larger the gate diameter is, the higher the cavity pressure obtain. Because of the injection pressure loss is smaller when the melt through the gate. The cavity pressure of trumpet type nozzle is larger the straight type due to the pressure is easy to deliver to the cavity.
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