Extrusion International 2-2025

46 Extrusion International 2/2025 • Host interface of the mixer to the operator interface of the machine • Further reduction of the nal moisture content of the material • Improved accuracy in the dosing of additives • Reduced energy consumption of the entire process (minimumW/kg consumption) • Automatic spinning head adjustment of the dosing system for extremely fast throughput changes As a result, the following further developments were incorporated into the series: • Automatic dew point control and improved drying of the material through automatically controlled air ow to the hopper. This adapts to uctuations in the material and ambient conditions. • Conveying the material with dehumidi ed air from the dryer to a small machine hopper with minimal volume. • Gravimetric loss-in-weight dosing, which follows the extruder speed synchronously and automatical- ly compensates for uctuations in the bulk density of the material. • Variable-speed dryer blower and heat recovery system that returns the heat from the dryer to the heating process. • Special spinning head switching software for the gravimetric loss-in-weight dosing unit to cope with rapid, extensive changes in machine throughput. • Wireless interface software to the machine inter- face via TC/IP for complete system integration. After completion of the development project, the rst system was delivered and installed to the full sat - isfaction of the customer. Since then, further systems have been and are regularly supplied to FET with the complete Motan Colortronic accessory program for their customers all over the world. Motan Colortronic provides the material supply for these projects. Depending on the equipment, gravi- metric dosing systems, conveyor systems and drying systems are used. Today, there is a wide range of polymers that are used worldwide for medical applications. Absorbable sutures are mainly made from synthetic polymers. Most sutures are produced either as mono laments or as multi lament yarns, which are further processed into suture material. They are based on a homopoly- mer or combinations of different block copolymers. The materials used are PLA (polylactic acid), PGA (polyglycolic acid), PCL (polycaprolactone), P4HB (po- ly-4-hydroxybutyrate), PDO (poly-p-dioxanone) and PTMC (polytrimethylcarbonate). These polymers are used due to their high biocompatibility, low toxicity and adjustable absorption rates. FET has processed over 70 different types of poly- mers in the form of mono laments, multi laments and nonwovens, including polymers from sustainable sources. This process involved working closely with re- search institutions and raw material manufacturers to carry out tests and evaluations. During extrusion, care must be taken to ensure that the polymer does not degrade before or during process- ing, which is why it must be dried precisely before extru- FIBER EXTRUSION, MATERIAL HANDLING – CASE STUDY Multi lament plant at the FET Fiber Development Center (©FET) motan glass machine hopper for holding specially modi ed glass containers with dried material (©FET) Multi lament systems at the FET Fiber Development Center (©FET)