Definition of Filament yarn? Manufacturing Process of Filament yarn?

Filament Yarns :

A filament yarn is a collection of parallel bundles of closely spaced filaments along the entire length of the yarn. Man-made yarn is made by spinning out the required number of filaments in a single operation to the desired linear density. Yarns with only one filament are known as mono filament and those with multiple filaments are known as poly filament.

Spinning method of Filament yarn :

Most synthetic fibers are extracted using polymers derived from petroleum and natural gas byproducts, including polyethylene terephthalate (PET) and nylon, as well as compounds such as acrylics, polyurethane, and polypropylene. Polymers are first converted from solid to liquid by melting, dissolving using solvents, etc. The liquid polymer is then extruded through a spinneret to convert the solution into filament. There are four main types of synthetic fiber production techniques: dry spinning, wet spinning, melt spinning and gel spinning.

A spinneret is a metal material that contains from one to hundreds of tiny holes. Liquid polymer is injected through these tiny openings to form filaments from the polymer solution.

This process of extrusion and solidification of numerous filaments is called spinning of polymers. There are two types of extrusion: single-screw and twin-screw extrusion.

• Single screw-extrusion: This is one of the primary operations in polymer processing. Single screw extrusion processes pressurize the polymer melt and force it through a die or inject it into a mold. Most single-screw extrusion machines are plasticized in operation, taking solids in pellet or powder form and melting them while simultaneously creating pressure.

• Twin-screw extrusion: It is generally used for mixing, compounding or reacting polymeric materials. The flexibility of the twin-screw extrusion tool allows the operation to be designed specifically for the processing. For example, two screws may be co-rotating or counter-rotating, inter-meshing or non-inter-meshing. The design and configuration of screws can also be modified by using forward conveying elements, reverse conveying elements, kneading blocks and other designs that can help obtain specific mixing characteristics.