American Kuhne has developed a 16-mm micro extruder designed to process fluoropolymers for miniature medical devices such as fine wire jacketing for neuromodulation, microdialysis tubing, and neonatal intravenous (IV) catheter tubing. These applications typically require an extruder that can process fluoropolymers (ETFE, PFA, and FEP) at very low volumes down to 3.4 g/min (0.45 lb/hr).
Processing fluoropolymers on extruders smaller than 16 mm is difficult because these machines require special corrosion-resistant screw materials that generally have low torsional strength and are prone to break at diameters below 16 mm, says the supplier. The smallest extruders for these applications have traditionally been 0.75 in. (19 mm). The benefit of a 16-mm extruder is approximately 45% reduction in minimum output rate and a short residence time in the barrel, which helps to minimize thermal degradation.