Simulation of extrusion of high density polyethylene tubes Antonios Koutelieris, Kyriaki Kioupi, Onoufrios Haralampous, Konstantinos Kitsakis, Nikolaos Vaxevanidis and John Kechagias MATEC Web Conf., 112 (2017) 04004 Published online: 03 July 2017 DOI: 10.1051/matecconf/201711204004