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Manufacturing of Fibre-Polymer Composites
Mosarruf HossainDept. of Aeronautical EngineeringMilitary Institute of Science & Technology.Dhaka, Bangladesh.
Introduction
Contents 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
Manufacturing of Fibres 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
Manufacturing of Carbon Fibre
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.
Manufacturing of Carbon Fibre
PAN is strechted into long thin element.
The filaments are heated in multistage.
Manufacturing of Glass Fibre
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
Manufacturing of Glass Fibre-Polymer Glass fibre is manufactured using a viscous drawing process.
Silica and metal powders are blended and melted
Heated on a furnace at 1400oC
Manufacturing of Aramid Fibre
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.
Manufacturing of Aramid Fibre
The polymers are dissolves in Strong Acid
This blend is extruded in a spinnerer at about 100 oC
Comparison Between Different Fibres.
Manufacturing Process of Fibre-Polymer 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.
Manufacturing Process of Fibre-Polymer 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
Prepregs 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.
Dry Fabrics 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.
Composite Manufacturing using Prepegs There are several ways of manufacturing composites using prepregs
Manual Lay-up Automated Tape Lay-up Automated Fibre Placement
Manual Lay-Up 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.
Automated Tape Lay-up 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
Automated Fibre Placement 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.
Composites Manufacturing by Resin Infusion 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
Resin Transfer Molding
Fabric is placed inside the cavity which is a two side
mold.
Fabric plies are stacked to the required orientation and
thickness.
Fibre reinforce
ment with
binder
Binded rein-
forcement transfer to
mold
Binded reinforcement being shaped under
pressure
Ready dry
preform
Vacuum Assisted RTM
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
Preform in RTM mold
Resin being
injected into
preform
Fully impregnated prefor
m being cured
Cured composite
Resin Film Infusion 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
Filament Winding 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.
Pultrusion
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
Machining of the composites 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.
Future Scope of Fibre-Polymer Composite Manufacturing 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”
Conclusion
Question- Answers
Thank You