Inverse designing simulation of extrusion die of auto rubber seal and verifications

Abstract

In the present study, the extrusion die of an auto rubber seal was designed by inverse extrusion simulation with Polyflow CFD software, and it was verified by real extrusion test. After the ethylene propylene diene mono rheological data were analysed, Bird-Carreau rheological model was employed. Three different structures of extrusion die flow channels were considered: one was straight channel with constant cross-section, another was adaptive channel with variational cross-section, and the third was compositive channel with constant and variational cross-section. In the production of rubber seal, the extrudate swells after flowing out of the die shape, and then shrinks because of the traction extrusion. So the extrusion die and flow channel gotten by inverse simulation need to be zoomed in with some expansion ratio, which are called expanded die and expanded channel. According to the structure of the expanded die and channel, a real extrusion die was manufactured and an extrusion test was carried out. Meanwhile, direct extrusion simulation was performed. The extrudate of direct simulation was coincident to that of test, so the extrusion die designed by inverse simulation was reasonable. Moreover, from the results of die inlet pressure, the adaptive channel with variational cross-section is better than the straight channel and compositive channel.