An innovative method of die design and evaluation of flow balance for thermoplastics extrusion profiles

Abstract

In this article, a computational and experimental method for flow balancing of a U‐shaped die profile with nonuniform thicknesses is presented. The approach was to implement a flow restricting mechanism along the melt flow path. A parametric study based on the restrictor dimensions was carried out to attain a preliminary optimal design. Simulations were performed using Fluent software to analyze the flow velocity at the die exit. Experimental study was then carried out at various restrictor positions for the purpose of attaining a desirable flow balance. The velocity at various segments of the die exit was measured utilizing an innovative procedure by implementing the “separating blades.” Experimental findings were compared with those of simulations which showed an acceptable agreement. The results suggest that a flexible die can be designed to achieve a flow balance under various processing conditions. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

A modular extrusion die design to produce continuous glass fibers reinforced PVC‐wood composite profiles

“…Sections of the die are numbered and described in Table . To resolve the issue of flow balancing, two strategies were undertaken: (1) avoiding sharp change in direction of flow from the extruder head towards the die exit, and (2) implementing a flow restrictor mechanism to balance the flow for all cross sections (as proposed by Zolfaghari et al ). The die design consisted of three main zones: adaptor, housing, and land.…”

Numerical shape optimization as an approach to extrusion die design

“…The second option for geometry representation is the use of a parameterization. The ways in which parameterization can be applied are manifold, ranging from very simple approaches-such as the variation of flow channel height and length [3][4][5][6][7]9,14]-to more elaborate approaches where free-form surfaces are represented using splines [2]. Advantageous about parameterization techniques is the reduction to very few design parameters, which afford more freedom in the choice of the optimization algorithm.…”

“…Differences lie in the details. For example, either the average velocity or the flux can be used in the least-squares term, and the evaluation of the term can be done in different ways: it can be aggregated over the nodes, the cells or small segments that the outflow cross section is subdivided into [1][2][3][4][5]. In addition to this primary criterion, some groups examined secondary criteria such as pressure loss or dwell periods [3,[6][7][8][9]].…”

Rheological Modeling of Polymeric Melts in Extruders upon Two-Dimensional Shear Flow

“…Various technological processes for production of polymeric products are based on extrusion of polymeric melts using ahollow tool of desired cross-section called ad ie (Rauwendaal, 2014;Zolfaghari et al, 2009). In some geometry, working surfaces of the main elements of the die are assembled in circular cylindrical channels to produce extruded tubular blanks, which are then used for the manufacture of final products.…”