Abstract: Based on the Bird-Carreau viscosity model, a threedimensional isothermal numerical model was established for the microtubuleextrusion molding by the finite element method, with the emphasis on the influence of the wall thickness, die swell, velocity distribution, shear rate distribution, pressure drop in the microextrusion molding. It showed that the swell and deformation of the extrudate increased with increasing wall thickness when the polymer melt flow rate was equal under different wall thickness condition. The melt secondary flow enhanced at the die exit plane, but the extrusion speed, shear rate and pressure drop within the die decreased with increasing wall thickness. It was conducive to improve the product quality if the wall thickness was increased appropriately.

Key words: micro-extrusion molding, wall thickness, die pressure drop, shear rate