Extrusion: L/D=30, compression ratio=1:3.5
Metering: one or more spinning gear pumps receives the molten polymer and sends it through the spinning pack to homogenize the product, feed the spinning pack at a constant rate, and prevent fluctuation due to screw extruder.
Spinning: the spinning pack consists of three parts-filters, distributor (which distributes the molten polymer over to die surface) and the die. The diameter of the die varies from 0.5 to 1.5mm, depending on the denier required.
Quenching: newly extruded filaments are cooled in a good “box" which will distribute 3 m3/min of cool air without damaging the filaments.
Finishing: to improve antistatic and reduce abrasion.
Hot Stretching: to enhance the physico-mechanical properties.
Crimping: to improve the bulk.
Thermosetting: it is a treatment in hot air or steam that removes the internal stresses and relaxes fibers. The resultant fibers are heat-set with increased denier.
Cutting: fibers are cut into 20 to 120 mm length depending on whether they are intended for cotton or woolen system.
Read more: http://textilelearner.blogspot.com/2013/01/polypropylene-fiber-and-its.html#ixzz4KnkyjDzQ