In The Name Of ALLAH,
The Most Gracious,The Most Merciful.
Department of Textile Engineering
Mehran University of Engineering &
1)DEFINITION OF SPINNING.
2)BASIC TERM USE IN SPINNING.
3)SPINNING METHOD(GENERAL STEPS).
4)TYPES OF SPINNING METHOD.
“Spinning is the process of
converting fibers into yarn”.
“The process of extrusion &
solidification of endless filament”.
2) BASIC TERM…
a) Spinneret:- A nozzle or plate
provided with fine holes through which a
fiber forming solution or melt is extruded in
fiber manufacture is called spinneret. It work
as a principle, to a bathroom shower head.
b) Extrusion:- Extrusion is a forcing or pumping the spinning
solution through the tiny holes of a spinneret.
3) Method of spinning (general steps)…..
All manufactured fiber-spinning processes are based on following
three(3) general steps:
1) Preparing a viscous dope (a thick solution) or melt.
2) Forcing or extruding the dope or melt through an opening in a
spinneret to form a fiber.
3) Solidifying the fiber by coagulation, evaporation or cooling.
4) TYPES OF SPINNIG METHODS….
There are generally four spinning methods of producing
synthetic filaments that are,
a) Melt Spinning.
b) Dry Spinning.
c) Wet Spinning.
d) Gel Spinning.
a) MELT SPINNING..!
In Melt Spinning, the fiber forming substance is molted for extraction through
the spinneret & then directly solidified by cooling gases. Cooling gases reduce the
temperature of the filaments. Melt spun fiber can be extructed from the spinneret in
different cross-sectional shapes(round, trilobal, pentagonal, octagonal etc).
Example: Nylon, Olefin, Polyester, Saran & Sulfur.
b) DRY SPINNING…..
Dry spinning is also used for fiber forming substance in solution.
However instead of precipitating the polymer by dilution or chemical reaction,
solidification is achieved by evaporating the solvent in a stream of air or inert gas.
The filament do come in contact with a precipitating liquid, eliminating the
need for drying & easing solvent recovery.
Example:- Acetate, Triacetate, Acrylic, PBI, Spandex etc.
C) WET SPINNING………
Wet spinning is the oldest process. It is used for fiber-forming
substance that have been dissolved in a solvent. The spinnerets are
submerged in a chemical bath and as the filaments emerge they
precipitate from solution & solidify.
Because the solution is extruded directly into the precipitating
liquid, thus process for making fiber is called “Wet Spinning”.
Examples:- Rayon, Aramid, Acrylic etc.
d) GEL SPINNING……….
It is also known as Dry_wet spinning because the filament first
pass through air then are cooled further into a liquid bath. Gel
spinning is used to make very strong & other fiber having special
characteristic. They polymer here is a partially liquid or in a “Gel” state
which keeps the polymer chains some what bound together at various
points an liquid crystal form.