POLYTETRAFLUOROETHYLENE (PTFE) PASTE EXTRUSION: EXPERIMENTS AND FLOW SIMULATIONS

摘要

In this paper the effect of the physical properties of the lubricant and operating conditions and design characteristics of dies on the PTFE paste extrusion flow was examined experimentally in order to understand physically the process. Based on the experimental results, a rheological constitutive equation is proposed to model (he flow of poly-tetra-fluoro-ethylene (PTFE) paste. Steady-state compressible flow simulations are carried out, governed by the conservation equations of mass and momentum under isothermal conditions, and taking into account a slip law at the wall due to the presence of lubricant in the paste. The effects of compressibility and slip are shown to be essential for the results to be in good agreement with experimental observations.