NON-NEWTONIAN FLOW ANALYSIS OF 3D BLOW MOLDING OF PLASTIC BOTTLES USING POLYFLOW

Abstract

Blow molding is a widely used manufacturing process for producing hollow plastic products
such as bottles and containers. Accurate prediction of wall thickness distribution is critical for
ensuring mechanical integrity while minimizing material usage. This study presents a
numerical investigation of the stretch–blow molding process of polyethylene terephthalate
(PET) bottles using finite element analysis. A time-dependent, non-Newtonian flow model is
developed using ANSYS Polyflow, incorporating Lagrangian mesh tracking, contact
modeling, and penalty-based mold interaction. Both 2D axisymmetric and 3D shell-based
simulations are performed to evaluate deformation behavior, velocity distribution, and final
wall thickness. The results demonstrate good agreement with experimentally observed
thickness trends and identify critical thinning regions near the bottle shoulder and edges. The
proposed approach provides a reliable framework for optimizing preform geometry and process
parameters to achieve defect-free bottle production.