Describes the different equipments?components that are used while making fibers. Covers melt, dry and solution spinning.

1. Contents
• Introduction
• Melt Spinning
• Extruder
• Spin Filter
• Gear pump/Steam pack
• Spinneret
• Quenching Zone
• Wind-Up Devices
• Solution Spinning
• Dry Spinning Line
• Feed
• Candle Filter
• Spinneret
• Spinning Cell
• Winding Assembly
• Wet Spinning Line
• Reaction Vessel
• Filter
• Metering Pump
• Spinneret
• Coagulation Bath
• Winding Assembly

2. INTRODUCTION
• Spinning is the manufacturing process in making
polymer fibers
• Two types of spinning – melt and solution
• Melt Spinning is simple &widely used method
• Solution Spinning is applied for those polymers which
are difficult to melt process
• Thermoplastics are extruded
• Thermosets are dissolved in suitable solvents

3. Simplest method
Able to spin at higher speeds
Granules must be dried prior to extrusion
The melt so formed is homogenized and is uniform
Might be used in both continuous and batch
processes
Extrusion Spin Filter  Quenching
MELT SPINNING

5. Components Involved

6. • Extruder is the main component of the spinning
process. Its shearing action is responsible to convert
the granules into a uniform melt. The granules must
be dried properly prior to the extrusion process. The
moisture level must not exceed 0.05%. This polymer
melt is then transported under higher pressure to
succeeding component.
• Spin Filter is a series of stainless steel wires of
different mesh sizes. It is carried to further
homogenize the melt and remove any metal pieces,
semisolid/degraded polymer or any other impurities.
Any gas bubbles in the melt are also removed here.
• When the melt is being transferred to Spin Filter,
Gear Pumps/Steam Packs are used which applies
higher pressure/higher temp to smoothen the flow &
further homogenize it.

8. • Spinneret is made up of plate consisting of a number
of capillaries through which the melt is forced to pass,
thus, forming a fine stream of fluid. The spinnerets are
made of stainless steel 3-30 mm thick and contain
holes of diameter 100-500 x10-6m. The number of
holes varies from two to four for monofilaments to up
to 60,000 for heads contributing to a staple tow.
• Quenching Zone is the chamber which is responsible
for cooling of the spun fibers. Three types of air-flow
systems are employed for this – Cross-Flow, In-Flow,
Out-Flow. Cross-Flow is used for large deniers &
rectangular spin packs. In-Flow is used in ring shaped
arrangement. Out-Flow is used for staple fibers in ring
shaped arrangements.

12. • Wind-Up Devices accounts for the assembly which
recollects the spun fibers. A tube roll which maintains
the take up speed. It then passes through 2 godets
and then to a forked system that traverses it on the
preceding rollers. In high speed spinning godets are
replaced with grooved rollers.

13. It is being used before melt spinning
Carried out when polymer cannot be melt processed
Polymer is dissolved in suitable solvents
Is of 2 type – Dry & Wet
The solvent is removed by evaporation in dry
spinning
The solvent is removed by coagulation in wet
spinning
SOLUTION SPINNING

14. Dry Spinning Line

15. • Feed contains filtered polymer solution, known as
“Dope”, which is transferred to a metering pump.
• Candle Filter does the same function as Spin Filter.
• Spinneret in this case is 5 mm thick made from nickel
or stainless steel. Orifice diameter is 0.02-0.03 mm. 3
different types of spinneret – Bowl, Hat and Ring.
• Spinning Cell is around 10m high & 25-45 cm in
diameter, jacketed by a heating fluid. Drying gas
enters through hot air inlet in the direction of filament
bundle. It is sucked out from gas outlet with the help of
vacuum. The gas flow rate is stated to be around 1-
2ms-1. The drying chamber must be leak-proof and the
density of the solvent in the chamber must not be
allowed at any time to go above its explosive limit.

16. • Winding Assembly After emerging from the drying
chamber an oil-based finish (Finish Applicator) is
applied to the yarn before winding. This is mainly to
impart cohesion, reduce friction and to reduce static
accumulation. The yarns are then wound at 200-1500
m min-1 on winding rollers as the filament bundles
pass through godets.

17. Wet Spinning Line

18. • Polymer & Solvent are mixed in the Reaction Vessel
having stirring devices. The solution mixture, thus,
obtained is called Dope. Within this vessel it is degassed
to remove any unreacted monomer & air.
• Filter receives this degassed solution & removes any
leftover physical impurities and further homogenizes it.
• Metering pump transfers this homogeneous solution
mixture under high pressure to the spinneret.
• Spinneret in this case is thin, made from malleable
material & has 200-600 holes of diameter 0.005-0.025
cm.
• The filaments from spinneret are coagulated in
Coagulation Bath which might be followed by a series of
baths to increase precipitant concentrations

19. • Winding Assembly After coagulation, the fibers
are washed to remove any residual solvent &
dried. Then finish is applied to the yarn, further
dried & wound over to obtain a tow.