SML's Austrofil HT spinning lines are renowned for their high-quality PP yarn production, especially in the field of high tenacity (HT) products. To increase output even further, SML has developed a new 45 mm extruder dedicated to multifilament yarn production. The new Austrofil HO-LT extruder allows HT lines to achieve up to 25% more output while maintaining the premium mechanical properties of PP yarns.
HO-LT extruder to improve spinning processes
The new extruder is based on SML´s proprietary HO-LT technology (high output – low temperature) – a concept that has been successfully used in cast film and sheet extrusion for over 10 years. The HO‑LT technology offers several advantages that are directly beneficial for fibre spinning: its characteristic gentle polymer melting and short residence times improve the spinning process. The melt temperature stays within a moderate, narrow band across a wide output range. This ensures consistent and excellent yarn properties from low to high titre. Short residence times enable quick product and material changes, while the HO-LT extruder still provides exceptional melt‑mixing – a perfect match for dope‑dyed yarn production.
Tested across the full titre range
The HO‑LT extruder has been extensively tested both in the SML Technology Centre and on‑site at customer facilities, covering the full titre range of the Austrofil HT lines (150–4,000 den / 165–4,400 dtex). The increased extrusion output allows the production capacity of an Austrofil HT line for titre > 1,300 dtex to be increased to up to 200 kg/h. The quenching unit and stretching unit with the unique hot-air oven have also been harnessed to achieve outstanding high tenacities of over 7 g/den for PP multifilament yarn.
Lower energy consumption
Apart from its performance, the HO-LT extruder also stands out with its exceptional energy efficiency. Compared with conventional extruders, it consumes significantly less power – a genuine advantage at a time of rising energy costs.
“Overall, the development of the Austrofil HO-LT extruder is a perfect addition to SML’s spinning line portfolio and and facilitates a cost-effective production with high output,” says Stefan Dambauer, Product Manager at SML. The new extruder can also be deployed on SML Austrofil VERTEX spinning lines for manufacturing low‑titre PP yarns for textile applications.
