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