Modelling Flow of Optical Fibre through Extrusion Heads

This presentation was made at the 2019 NAFEMS World Congress in Quebec Canada

Resource Abstract

The paper deals with the simulation of a core/cladding extrusion process of Plastic Optical Fibre (POF). It reflects part of the work carried out in the context of an R&D project financed by Valencian Community in Spain. AITEX, who is one of the partners in the project, subcontracted to Principia the simulation work presented here. The final goals pursued are reducing the production costs of the POF and, also, studying the possibility of obtaining new core geometries with a potential yet to be explored.



The configuration studied is a single filament fibre, composed of two polymers. The core is constituted by polymethyl methacrylate (PMMA) and the cladding is made of polyvinylidene fluoride (PVDF). Various types of cross-sections of the core were analysed in order to optimise the characteristics of the final product. The two materials arrive in a molten state at the extrusion head, where the final filament is produced. Mechanical and thermal properties were available for both materials over the temperature range of interest and viscoplastic material descriptions were used for modelling the materials in their molten state.



The study of the process was decomposed into three phases. The first one involves the flow of the molten materials arriving to the extrusion head; this is the most relevant phase from the viewpoint of the geometry of the core. In the second one, the still molten materials emerge from the head, already forming a combined cross-section. In the third and final phase, the materials solidify and the final section of the filament is produced. Different modelling strategies were employed for simulating the different phases. The first phase was analysed with Abaqus/Explicit, using ALE adaptive meshing techniques. By contrast, for the cooling and solidification phase, the calculations were conducted with Abaqus/Standard using neo-Hookean material descriptions for the two materials. The results obtained in the calculations allowed establishing the more promising cross-sections for extrusion of the core.