Abstract: Basedon a viscosity model of polymeric melt representing the rheological characteristics in mi-croscale,the influence ofmelt viscosityon the filling process in micro injection molding was investigated through analyzingthepressuredistributionsof ABS at different inlet temperatures in different mi- crochannels.Numerical simulation showed that the microscale viscosity was lower than the conventional oneand reduced with the decreasing characteristic dimension of microchannel section. In addition, the curves of melt velocity at the sectionofz=5 mm became more smooth with decreasing characteristic di mension of microchannel section

Key words: micro injection molding;melt flowing, microscale viscosity model, numerical simulation