polymer

1. Mosarruf Hossain
Dept. of Aeronautical Engineering
Military Institute of Science &
Technology.
Dhaka, Bangladesh.

3.  Manufacturing of Fibres
 Manufacturing of Carbon Fibres
 Manufacturing of Glass Fibres
 Manufacturing of Aramid Fibres
 Manufacturing process of Fibre-Polymers
 Prepregs
 Dry Frabrics
 Composite Manufacturing using Prepregs
 Manual Lay-up
 Automated Tape Lay-up
 Automated Fibre Placements
 Composite Manufacturing by Resin Infusion
 Resin Transfer Molding
 Vacuum Assisted Resin Transfer Molding
 Resin Film Infusion
 Filament Winding
 Pultrusion
 Machining of the composites
 Future Scope of Fibre-Polymer Composite
Manufacturing
 Conclusion
 Question-Answer

4.  Fibre is a natural or synthetic substance that is significantly longer than it’s wide.
 Some of the Strongest Fibres are
 Carbon Fibre
 Glass Fibre
 Aramid Fibre or Kevlar

5.  Carbon Fibres are
 Highly stiff
 Strong
 Lightweight
 The properties of Carbon Fibres depends on the process of manufacturing.
 Carbon Fibre can be extracted from polyacrylonitrile (PAN), pitch and rayon.
 Mostly Carbon is fetched from PAN.

6. PAN is
strechted into
long thin
element.
The filaments
are heated in
multistage.
The filaments
are oxidizes in
air at 200-300oC
Then the
filaments are
heated at
1500oC in inert
condition
After heating
the carbon
content
becomes 93-95%

7.  Glass Fibre composites has
 Low Stiffness to weight ratio
 Low elastic modulus
 Low Dielectric properties
 Cheaper than Carbon Fibre
 There are two types of Glass fibres
 E-Glass
 S-Glass

8.  Glass fibre is manufactured using a viscous drawing process.
Silica and metal
powders are
blended and
melted
Heated on a
furnace at
1400oC Molten glass
gets flowed
over thin hole
plates
Glass then
Solidifies in the
holes
When leaving
furnace the
glasses are
cooled by water
steam

9.  Aramid or aromatic polymer is one of the most important material for aerospace
industry
 It is also called Kevlar.
 Aramid fibres can absorb a large amount of energy during fracture,. [6]
 Aramid Fibres are also good vibration dumping material.

10. The polymers are
dissolves in Strong
Acid
This blend is
extruded in a
spinnerer at about
100 oC The molecular
chains are grouped
into domains called
fibrils.
These Fibrils are
stacked together.
The bundles of
fibrils are the
desired Aramid

12.  Composites for aircraft applications are manufactured in two basic material forms:
Laminate:
It is a solid material having multiple layer of fibre and resin in a single bond.
Sandwich:
It consist of thin skins which are bonded using adhesive film to a lightweight thick
core material.

13.  Depending on the combination of the polymer with the fibres Composite
manufacturing process can be divided in to two categories.
A) Prepeg Based Process
B) Resin-infusion Process

14.  The term prepegs is short form for pre-impregnated fibres.
 It is a two-paret sheet material consisting of fibres and resin.
 There are many methods of producing prepeg.
1.Solution Dip
2. Solution Spray
3.Hot melt technique
 In Solution Dip method, the resin is dissolved to a solvent having 40-50% solid
content
 In Solution Spray method, the resin is sprayed on to the fibres
 In Hot melt technique, Low viscosity resin is directly coated over the fibres.

15.  There are several advantages gained by using fabric rather than prepreg, including
lower material cost, infinite storage life, no need for storage in a freezer
 The most common fabrics is woven fabric produced on weaving looms
 the main styles are plain, twill and satin.
 In plain woven fabric, each warp tow alternately crosses over and under each
intersecting weft tow.
 Twill and satin fabrics are woven such that the tows go over and under multiple
tows.

16.  There are several ways of manufacturing composites using prepregs
 Manual Lay-up
 Automated Tape Lay-up
 Automated Fibre Placement

17.  Manual lay-up involves
 Cutting the prepreg to size,
 Removing the backing paper
 Stacking the prepreg plies by hand onto the tool surface.
• The prepreg plies are oriented with their fibres aligned in the main loading
directions acting on the component.
• The most common pattern used in the lay-up of plies for aircraft components is
[0/+45/–45/90]
• A composite with this lay-up is called quasi-isotropic.

18.  Automated tape lay-up (ATL) is an automated process used to lay-up prepreg tape.
 This process is cost effective and Time efficient.
 The key component is a computer controlled tape-laying head that deposits prepreg
onto the tool at a fast rate with great accuracy.
 As the tape is laid down, the head removes the backing paper and applies a
compaction force onto the prepreg
 After the automated tape lay-up is complete, the prepreg is consolidated and cured.
 The ATL process is capable of producing flat or slightly curved composite parts ,it is
not suited for highly contoured parts

19.  In the AFP process, narrow strips of prepreg tape are pulled off holding spools and
fed into the fibre placement head.
 Within the head, which contain about 12 000 fibres and are approximately 3 mm
wide, are collimated into bundles of 12, 24 or 32 narrow strips of prepregs.
 These narrow strips are deposited onto the mandrel which has the shape of the final
component.
 After the lay-up process is complete, the prepreg is cured.

20.  The Aerospace industry avoiding composite manufacturing process which contains
prepregs.
 prepreg is expensive, must be stored in a freezer, has limited shelf-life, and must be
cured in an autoclave which is slow and expensive.
 The industry is producing composite components using dry fabric which is infused
with liquid resin and then immediately consolidated and cured.
 Some of the resin infusion processes are
 Resin Transfer Molding
 Vacuum Assisted Resin Transfer Molding
 Resin Film Infusion
 Filament Winding
 Pultrusion

21. Fabric is placed
inside the cavity
which is a two side
mold.
Fabric plies are
stacked to the
required
orientation and
thickness.
Liquid resin is
injected into the
mould by means of
a pump
The resin flows
through the open
spaces of the fabric
until the mould is
completely filled.
The mould is
heated in order to
gel and cure the
polymer matrix
Fibre
reinforcem
ent with
binder
Binded rein-
forcement
transfer to
mold
Binded
reinforceme
nt being
shaped
under
pressure
Ready dry
preform

22. The fabric stack is
enclosed and
sealed within a
flexible plastic bag.
The bag is connected at
one point to a liquid
resin source and at
another point to a
vacuum-pump system
Air is then remove
by vacuum pump
which squeezes the
bag
Liquid resin flows
into the bag under
the pressure
differential.
After the fabric is
completely infused
with resin, the
material is cured at
high temperature.
Preform
in RTM
mold
Resin
being
injected
into
preform
Fully
impregn
ated
preform
being
cured
Cured
compo
site

23.  The resin film infusion (RFI) process is suited for making relatively large structures.
 The process uses an open mould upon which layers of dry fabric and solid resin film
are stacked.
 The materials are sealed within a vacuum bag and then air is removed using a
vacuum pump
 The entire assembly is placed into an autoclave and subjected to pressure and heat

24.  Filament winding is a manufacturing process where cylindrical components are
made by winding continuous fibre.
 There are two types of filament winding process.
1)Wet winding:
Wet winding involves passing continuous tows through a resin bath before reaching a
feed head.
2) Prepreg winding:
Prepreg winding involves depositing thin strips of prepreg onto the mandrel in a
similar manner to the ATP process.
 After winding is complete, the composite is cured at room temperature.

25. Multi-directional
glass fiber mat, are
guided through a
liquid resin bath
The reinforcements
are then guided
and shaped into the
profile to be
produced
Then the material
progresses through
the heated die,
which is shaped to
as design profile
The resin changes
from a liquid to a
gel and finally
becomes hard
plastic.
A pulling device
grips the cured
material and pulls
the material
through the die

26.  The manufacturing processes produce almost the net shape of the component.
 Most machining operation for composites are removing extra materials by trimming
or drilling.
 The Carbon-epoxy composites are cut using water jets to avoid edge damage.
 . Drilling must be performed using a sharp bit at the correct force and feed-rate .
 The application of excessive force causes push-down damage.

27.  Future Scopes are
 Cost Effective
 High Production Rate
 Relaible Manufacturing method
 To produce Materials faster, Out of Autoclave systems are more appreciated.
 Some of the latest research are going on “Additive manufacturing of high
performance composite structures”, “Development of LASER heating in the
manufacturing process” and “Automated fibre placement”