Abstract: A complicated hollow part was selected as the research object in this paper. The method of parison temperature difference was proposed for optimizing the wall thickness distribution uniformity of hollow parts according to the principles of polymer rheology. Before the blowing up of the parison, the locations on the parison that would be largely deformed was pre-cooled with air or water, and a temperature gradient was formed on the parison before the mold closed. By this method the standard deviation of the wall thickness of a fuel tank decreased from 0.7249 to 0.4475 and 0.4582, and the uniformity of the wall thickness was raised obviously.

Key words: optimization, extrusion blow molding, hollow part, wall thickness distribution, parison temperature difference method