The Study Of Micro-scale Effects On Filling Process Of Polymer Melt

It is became a trend that how to make plastic parts have more micro-structures, function and reduce their size. We investigate the behavior of polymeric flow filling the micro-channels and get the three non-dimensional parameters. Numerical simulation of non-isothermal flow was used to analysis the effects of surface tension, size-dependent viscosity and wall slip about the polymeric flow filling the micro-channel. The major conclusions are following:1. We have investigated the change of interface energy of three phase systems amount polymeric flow, the wall of micro-channels and atmosphere, when polymeric flow filling the micro-channels. The effect of interface (surface) tension was translated into the extern pressure loss at the front of melt.2.In older to describe the behaviors of polymeric flow filling the channels, the control equation that was used to described conventional injection molding of filling process was revised by considering the effects of surface tension, size-dependent viscosity and wall slip. We also get three normalized rheological parameters.3. The numerical simulation of polymeric flow filling the micro-channels was used to analysis the consequences of micro-scale phenomena, particularly, surface tension, size-dependent viscosity and wall slip.4. At different apparent shearing rate, we investigated radial distribution of normalized velocity at melt front about five different models. We choose three different size micro-channels as geometrical model, the diameters of which are 1μm, 10μm,100μm. The results of numerical simulation show that the effects of surface tension, wall slip and size-dependent viscosity all play important roles on the filling process. When the diameter of micro-channel is 10μm, the effect of surface tension is more important than other consequences of micro-scale phenomena, as the apparent shearing rate is low than 1.0 x 102 s-1. As the shearing rate become higher, the effects of surface tension and size-dependent viscosity will decrease and the effect of wall slip will increase. The smaller diameter of channel will make the effect of surface tension become more important.