Filament winding is a manufacturing technique used to create cylindrical structures like pressure vessels by tension-winding fiber strands around a rotating mandrel. The process can utilize materials such as glass, carbon, and various resins, with parameters affecting fiber tension, wet-out, and material properties. While it offers advantages like high reproducibility and fiber orientation, disadvantages include potential defects and challenges in mandrel extraction.

1. FILAMENT WINDING

2. CONTENTS
• Introduction
• Requirements for Manufacturing
• Brief Description of Process
• Types of Winding Process
• Materials Used
• Process Parameters
• Possible Cross sections
• Advantages
• Disadvantages
• Applications

3. INTRODUCTION
Filament winding is a fabrication technique mainly used for
manufacturing open or closed cylinders like pressure vessels
tanks or axisymmetric hollow structures.

4. The process involves winding filaments under tension over a
rotating mandrel.
The mandrel rotates around the spindle in X-axis while a
delivery eye on a carriage in Y-axis traverses horizontally in
line with the axis of the rotating mandrel, laying down fibers in
the desired pattern or angle.
The most common filaments are glass or carbon fibre strands.
These are impregnated in a bath with resin as they are wound
onto the mandrel.

5. Requirements for Manufacturing
1. Filament Winding Machines
2. Mandrel
3. Fibre Creels
4. Resin Bath

6. 1. Filament Winding Machine
• Basically similar to Conventional Lathe Machine performing
turning operation.

8. 2. Mandrel
• Mandrel is a cylindrical structure with either closed or open end
over which filament is wound.

9. 3. Fibre Creels
• Fibre in the form of filament is wound similar to a thread rolled over
a spool.

10. 4. Resin Bath
• It contains liquid resin, catalyst, pigments and UV absorbers.

11. Process

12. • A large number of fibre rovings are pulled towards the resin bath.
• Before entering the bath, rovings are gathered in the form of band
by passing them through stainless steel comb.
• At the end of the resin bath, the resin impregnated rovings are pulled
through a wiping device to remove excessive resin.
• Once the rovings have been thoroughly impregnated and wiped,
they are gathered on a flat band and positioned on mandrel.
• The band former is usually
located on the carriage which
traverses back and forth
parallel to the mandrel.

13. • In turn , mandrel rotates at lower speed to get precise
winding.
• After winding a number of layers of desired thickness, the
filament-wound part is cured in mandrel.
• The mandrel is extracted from cured part.
• The component is normally cured at high temperature
before removing the mandrel.
• As in pressure vessels , mandrel becomes an integral part
of filament wounded part.

14. Types of Winding Process
There are three types of winding based on wind angle
(The angle of roving band with respect to mandrel axis is
called wind angle. Wind Angle of 0 to 90 degreed can be
obtained)
• Helical Winding
• Circumferential Winding
• Polar Winding

15. HELICAL WINDING CIRCUMFERENTIAL
POLAR

16. For a Circular Mandrel,
Where N = Rotational Speed of Mandrel
V= Carriage Feed Rate
r = Radius of Mandrel
θ = wind Angle

17. MATERIALS USED
 FIBRES
• E-glass, S-glass,
• Carbon fibres
• Aramid
• Borons fibres.

18.  RESINS
• Epoxy
• Vinyl ester
• Polyester
• Polyurethane
• Phenolics
• Polyamides
Epoxy resin mixed with hardener

19. PARAMETERS
 Process Properties
• Fibre Tension
• Fibre Wet-Out
• Resin Content.
 Material Properties
 Environmental Properties

20. Fibre Tension & Resin Content
 Fibre Tension is created by pulling the rovings through a number of
fibre guides placed between the creels and resin bath.
 Adequate Fibre tension is needed to maintain fibre alignment in
mandrel and resin content.
 Mechanical actions on fibres in resin bath such as looping generally
creates additional fibre tension.
 Typical tension values range from 1.1 to 4.4N.
 Excessive fibre tension can cause
• Difference in resin content in inner and outer layers
• Residual stresses in finished product
• Large mandrel deflections.

22. Fibre Wet-Out
Fibre Wet-Out depends on
• Viscosity of resin at operating temperature
• Number of strands in a roving that determines
accessibility of resin to each strand.
• Fibre Tension.
• Speed of winding
• Length of Resin bath.
(For good Wet-Out , each roving should be under resin bath
for 1/3 to ½ seconds in a bath of 20cm)

23. Material Properties (Resin)
 The viscosity of resin bath should be low enough for impregnating
the fibre strands in resin bath, yet not so low that resin drips and
runs out easily.
(Usually a viscosity of 1-2 Pa-s is preferred)
 Should have relatively long pot life.
(Pot life is the amount of time taken for an initial mixed viscosity to
double)
 Should be chemically inert.
 Shouldn’t change its composition when subjected to high
temperature.

24. Possible cross sections

25. Advantages
• Highly reproducible nature of the process
• Continuous fiber over the entire part
• High fiber volume is obtainable
• Ability to orient fibers in the load direction (10° minimum
winding angle)
• Fiber and resin used in lowest cost form
• Size of component not restricted by oven or autoclave size
• Process automation (particularly with high volume) results
in cost savings

26. DISADVANTAGES
• Defects such as voids , delaminations and fibre wrinkles
• Part configuration must facilitate mandrel extraction
• Mandrel could be complex and expensive
• Inability to wind reverse curvature
• Inability to easily change fiber path within one layer
• Wound external surface may not be satisfactory for some
applications

27. APPLICATIONS
• Storage tank
• Railway tank car
• Pipe

28. THANK YOU