Modeling and Simulation of Suction Blow Molding Process for Producing Curved Ducts

Abstract

During suction blow molding process, the extruded parison undergoes twisting deformation within the mold cavity, as the air drawing flow around the deforming parison exerts non-uniform shear stresses on its surface. This research is devoted in developing a fluid-structure interaction model for predicting parison deformation during suction blow molding process, with a specific emphasis on the suction stage. A fluid flow model, based on Hele-Shaw approximations, is formulated to simulate the air drag force exerted on the parison surface. The rheology of the polymer during suction is assumed to obey the K-BKZ integral viscoelastic model. The numerical results of this study allowed identifying a clear correlation between the twisting deformation undergone by the parison during the suction stage, also observed experimentally and the design parameters, namely, the air suction speed, the geometry of the duct mold cavity, and the parison/mold eccentricity.