Experimental Study on Extrudate Swell and Die Geometry of Profile Extrusion

摘要

The objective of this study was to determine the swell behavior of a polymer melt and to design a die for forming a polymeric extrudate with a desired shape using profile profile extrusion. Polystyrene pellets were chosen to perform the profile extrusion experiments. First, the polystyrene pellets were melted and pushed through a quarter ring profile. The profile of the swelled extrudage agreed with the numerical predictions. A modified die was designed to produce a quater ring profile extrudate based on the direct extrusion problem (DEP) prediction. Polystyrene pellets were also melted and pushed through the modified die. The experimental results were close to the computational reslts. The melting temperature, die length, and melting residence time affect die swell behavior. The die sell ratio becomes smaller as the melting temperature and melting residence time are increased. As the die length is increased, the die well ratio is lowered. According to the die geometry predictions, an extrudate with the desired profile can be made precisely.