PIPE EXTRUSION. Battenfeld Extrusionstechnik and the University of Paderborn have developed a new, two-stage pipe die (type designation VSI) in a joint research project Stage one comprises a smearing thread for preliminary distribution of the melt, while the fine distribution is performed in stage two with the aid of a compact lattice basket This new form of gentle melt distribution has a series of advantages for pipe manufacturers, in terms of through put and product quality, which no other die concept has so far been able to offer.