- The spinnerets used in the production of most manufactured
fibers are similar, in principle, to a bathroom shower head. A spinneret
may have from one to several hundred holes. The tiny openings are very
sensitive to impurities and corrosion. The liquid feeding them must be
carefully filtered (not an easy task with very viscous materials) and,
in some cases, the spinneret must be made from very expensive,
corrosion-resistant metals. Maintenance is also critical, and spinnerets
must be removed and cleaned on a regular basis to prevent clogging.
As the filaments emerge from the holes in the spinneret, the liquid
polymer is converted first to a rubbery state and then solidified. This
process of extrusion and solidification of endless filaments is called
spinning, not to be confused with the textile operation of the same
name, where short pieces of staple fiber are twisted into yarn. There
are four methods of spinning filaments of manufactured fibers: wet, dry,
melt, and gel spinning.