Vacuum Bag Resin Infusioncam.bue.edu.eg/Presentations/16 May 2011/02-Session... · resin used in...

Bakir Plastics Co.1

Vacuum Bag Resin Infusion

An Innovative Fabricating Method For Composites

Bakir Plastics Co.2

Terminology

Fabrication Steps

Comparison Between Hand Lay-up And Vacuum Bag Resin Infusion

Bakir Plastics Co.3

Terminology

Composite Material – A material that is fabricated from two or

more material components of different

natures resulting in a new material with

properties different from the initial

materials.

Matrix - Is the component material containing all

other Component materials within its limits.

It usually starts as a thermosetting polymer

liquid or a thermoplastic solid.

(Also Ceramics, Carbon and metals).

Bakir Plastics Co.4

Terminology … continued

Thermosetting Plastics - The group of plastics that once set and

formed cannot be reshaped by heat.

Examples are: U.Polyesters, Epoxides,

Phenolics (liquid and powder). PURs,

Furan. Also powder Melamine and Urea

Fordmaldhyde.

Thermoplastic - The group of plastics that can be formed

and reformed by heat.

Examples are: PP and PA.

Bakir Plastics Co.5


Reinforcing Fibres – Is the main additive to the matrix that

together form the composite material. They

are made of: Glass, Plastics, Carbon,

Ceramics, Metal, and Natural Fibres.

They come in many forms.

Laminates - Simultaneous plies/layers of reinforcing

fibres that forms the wall thickness of the

composite. Each and every laminate can

posses similar or different properties.

Bakir Plastics Co.6


Additives - Materials that are added to the

matrix to influence its properties,

appearance, cost …. etc.

Core Material - Is a material of higher thickness and lower

density included between two composite

skins to notably increase its bending

strength with little increase in weight.

Examples are: Foams (PVC - PET - PUR

… etc.) - Honeycombs - Void cores.

Bakir Plastics Co.7


Cure - Is the chemical reaction or setting changing the polymer from the liquid into the solid state.

Cure Time - Is the time for the liquid polymer to set into a solid matrix.

Cure System - In the case of “Unsaturated Polyester”, is a group of one or more additives that causes the polymer to cure during the required period. They are called promoters, accelerators, catalysts & peroxides. In the case of “Epoxies and PURs” its the hardener.

Bakir Plastics Co.8


Pot Life - Is the life-time of the liquid polymer to set in

the dispensing container starting from the

time of mixing with the cure system.

Vacuum Bag - Is a film that contains all the Vacuum

Infusion System within. It is tightly sealed

with addhesive tapes against any air leaks.

Bakir Plastics Co.9


Perforated Release Film – A film that is placed in direct contact the

composite materials. It has the ability not to

stick to the cured resin matrix and allows

the resin to penetrate it from the bleeder to

the laminate reinforcements.

Breather /Bleeder/ - A fabric with a double function. It is used for

air suction through the vacuum pipe and

for resin distribution.

Bakir Plastics Co.10

Fabrication Steps Single Wall Wind Turbine Small Blade

Step 1 - Mould preparation & waxing


Fabrication Steps Single Wall Wind Turbine Small Blade … continued

Step 2 - Glassfiber Laminates are placed dry



Step 3 - The Perforated Release film is applied



Step 4 - Breather Bleeder cloth is placed



Step 5 - Vacuum Bag and pipes are sealed with an adhesive tape



Step 6 - Vacuum Bag is tested for air leaks



Step 7 - Resin is drawn into the laminates using vacuum



Step 8 - Start of removal of infusion material set after part curing



Step 9 - Removing the bagging film.



Step 10 - Removing the release film and breather



Step 11 - Removing the composite blade first half



Step 12 - The two produced blade halvesready to assemble together


Fabrication Steps Double Skin Sandwich Panel

Step 1 - Glassfiber Laminates for the outer skin are placed dry


Fabrication Steps Double Skin Sandwich Panel … continued

Step 2 - Perforated PUR Sheets are placed



Step 3 - Foam Core is placed next



Step 4 - The Inner Skin Glassfiber Laminates are placed



Step 5 - The Perforated Release film is applied



Step 6 - Breather / Bleeder cloth is placed.



Step 7 - Vacuum Bag is cut and prepared with the adhesive tape



Step 8 - Vacuum Bag and pipes are sealed with an adhesive tape and tested



Step 9 - Vacuum is applied and tested for air leaks



Step 10a - Resin is drawn into the laminates using vacuum.



Step 10b - Resin is spreading more



Step 10c - Resin is spreading further more



Step 10d - And more



Step 11 - The produced Sandwich Panel


Comparison Between Hand Lay-up And Vacuum Bag Resin Infusion

1- Method Description

Hand lay-up

Is the traditional wet laminating

method.

Resin infusion

Uses a sealed plastic film to

achieve a net vacuum on dry

fabric in order to draw resin

through that fabric


Comparison Between Hand Lay-up And Vacuum Bag Resin Infusion … continued

2- Fiber to resin ratio

Hand lay-up

Inacurate as the resin is applied

manually resulting in an

oversaturated state of the laminate.

A typical hand lay-up usually

results in excess of double the

resin used in resin infusion. And it

is difficult to remove the excess

resin

Resin infusion

Better fiber-to-resin ratio. Resin alone is very brittle, so any excess will actually weaken the part. The reinforcement materials starts dry, but compressed, when the resin is introduced. Any excess resin will eventually be sucked into the vacuum line. As a result, only the minimum amount of resin is introduced. This lowers weight, increases strength and maximizes the properties of composite.



3- Mechanical Properties

Hand lay-up

Mechanical properties are

pedictable and suitable for all sizes

of final products with performance

unaffected by excess resin weight

Resin infusion

Much higher mechanical properties /

specific strength, due to the usage of

the optimum resin to fiber ratio.



4- Product Quality

Hand lay-up

The human variable is of great

influence.

Resin infusion

Constant high quality. However, a

correct infusion strategy is

necessary.



5- Quality Risks

Hand lay-up

Straightforward. When something

goes wrong, one still can end with

this part, still suitable, however not

as good as being vacuum bagged.

Resin infusion

Due to the complexity and ease of

error in the infusion strategy, it is

very easy to destroy a part. Once

infusion begins, there is little that can

be done to correct a strategy error.



6- Materials Handling

Hand lay-up

Not easy and even messy.

Resin infusion

Easy. All materials are used in a dry

and clean condition.



7- Size of Job

Hand lay-up

Larger lay-ups are only possible

with the help of a lot of extra

hands.

Resin infusion

Unlimited. Even large lay-ups are

possible for a single-handed builder.



8- Costs

Hand lay-up

Initial low er capital costs but higher

labour cost .

Resin infusion

Extra costs for vacuum pump,

vacuum bag, sealant tape, tubing,

connectors, release film and resin

distribution material.



9- Simultaneous sandwich laminating

Hand lay-up

Difficult and messy. Needs highly

trained labour and adequate resins

formulation otherwise voids and

poor adhesion with the lamiate

skins will occur.

Resin infusion

Easier, due to the laying of the

materials in its dry forms. The resin

is introduced by suction filling all the

voids and resulting in full adhesion

with the skins.



10- Health

Hand lay-up

Due to the nature of the process

using open moulds, precautions

has to be taken to avoid health

hazards due to evolving fumes,

splashes or spills.

Resin infusion

Cleaner process. Vacuum infusion

provides a cleaner, safer and friendlier

work environment. There are no brushes

or rollers, and therefore no splashing,

spattering or dripping on onerself. There

are almost no resin fumes to contend with.

It is merely mixing the resin and pour it

into a bucket, from whence it is sucked in

fully automated fashion into the bag

covered laminates.

Vacuum Bag Resin Infusioncam.bue.edu.eg/Presentations/16 May 2011/02-Session... · resin used in...

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