Abstract: The theoretical models of melt flowing characterictics in microscale channels are constructed by model modification method according to the macroscopic rheological theories and the modeling technology for polymeric melt. Moreover, the influences of microscale viscosity, wall slip and convection heat transfer coefficient between polymer melt and mold wall on micro melt flowing are investigated by using numerical simulation method and compared with the existing experimental data. The results indicate that the viscosities of polymeric melt flowing in microchannels are obviously lower than those calculated with the conventional viscosity model and are proportional to the characteristic dimensions of microchannel. With the decrease of the characteristic dimensions of microchannel, the slip coefficients are obviously reduced, while the slip velocities of polymeric melt on the wall are increased. In addition, considering the surface convection heat transfer coefficients the distribution of melt temperature in microchannels is subject to the size effect. The flowing behaviors of polymeric melt in microchannels are different from those in macrochannels in some aspects.

Key words: Filling flow, Micro injection molding, Numerical simulation, Theoretical modeling