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Tuesday, December 30, 2008

How Fibreglass Is Made

Glass Fibre

Glass fibre being made by blending quarry products; sand, kaolin, limestone, colemanite and other such materials which are melted down. The quantities are carefully adjusted to obtain the type of glass fiber desired. At 1600°C, the liquid glass is passed through micro-fine bushings and simultaneously cooled to produce filaments from 5-24mm in diameter. Filaments are drawn together into a strand (closely associated) or roving (loosely associated), and coated with a “size” to provide filament cohesion and protect the glass from abrasion.

Glass Fibre


Making of Fibre Glass

There are two main types of manufacturing the glass fibre products:
-Direct melt process
-Marble remelt process
Glass Fibre Melt Spinning


Both of the process start with the raw materials in solid form that are mixed together and melted in a furnace.

In the Marble process, the molten material is sheared and rolled into marbles which are cooled and packaged. The marbles are taken to the fiber manufacturing facility where they are inserted into a can and remelted. The molten glass is extruded to the bushing to be formed into fiber.
While in the Direct melt process, the molten glass in the furnace goes right to the bushing for formation.

Direct Melt Process

Types of Fibre Glass

E-glass (electrical):
-lower alkali content (<1%) align="left">C-glass (chemical):
-best resistance to chemical attack.
-Mainly used in the form of surface tissue in the outer layer of laminates
R, S or T-glass:
-Manufacturers trade names of equivalent fibres.
-R (Vetrotex, France), S (Owen Corning, USA) and T (Nittobo, Japan)
-Higher tensile strength and modulus than E glass, with better wet strength retention.Higher ILSS and wet out properties are achieve through smaller filament diameter.
A-glass:
-Soda lime glass with high alkali content between 10-15%.
-Very poor mechanical properties but high resistant to chemical attacks.
D-glass: -Improved dielectric glass developed for high performance electronic applications.

Typical Fiber-Forming E-glass Formulation

Wednesday, December 17, 2008

Composite Fabrication: Spray Up / Spray Lay Up

Enough of definition and introduction..

Let us now move to the first composite processing method called SPRAY UP, an open mold process.

In this method, you will need a chopper gun that will chop away the glass roving. In this method, only glass roving only that can be use. While the resin mainly is polyester. If the finish product needs to have core the core have to incorporate separately.

The process in this method involve chopping the fiber in a hand-held gun and fed into a spray of catalysed resin directed at the mould. And then the deposited materials are left to cure under standard atmospheric conditions.

Typical Applications
Typical Applications are Simple enclosures, lightly loaded structural panels, e.g. caravan bodies, truck fairings, bathtubs, shower trays, some small dinghies, etc.

Advantages
The main advantage spray up method is it involve a very low cost tooling. It is a low cost way of quickly depositing fibre and resin and have been used for many years.

Disadvantages
Beside of the advantages, the disadvantages of this method should also take into consideration. By using this method, laminates tend to be very resin-rich. This will make the finish product will be a lot more heavier.

Because of the chopping process, the fiber is only short fibers. Thus some limitation of properties will apply. The properties will not the same as using long fibers. This consideration should be taking into account depending on your product application.

Futhermore, resins need to be low in viscosity to be sprayable. This generally compromises their mechanical and thermal properties
Spray Up Process

Friday, December 12, 2008

FyreRoc - A Fireproof Material for Composite

While surfing through the net to find some resin, I found an interesting resin that is fireproof. Most of the resin that been used in the composite industries is well known to be easily burn and produce toxic smoke and fume when subjected to extreme temperature but not with FyreRoc.

This fireproof resin was developed by Goodrich Corporation, originally developed for the needs of US Navy ships. This material is based on a patented resin system that will not burn, produce smoke, toxic fumes, or generate heat when exposed to fire or extreme temperatures.

And the good news is that FyreRoc can be use using variety of composite processing method using with glass fiber and carbon fiber as the reinforcement . Some of the potential products are:

Fire Door Cores Fire Doors Ablative LinersEngine Exhaust shieldsFire BarriersFloor PanelsWall PanelsGratingElectrical EnclosuresJoiner BulkheadsOxygen Barriers for organic and carbon matrix compositesFire BreaksExhaust ComponentsMarine StructuresAerospace PanelsTransportation Panels


FyreRoc Sandwich Panel

Thursday, December 11, 2008

Definition of Fibre Reinforced Composite

Fiber Reinforced Polymer (FRP) Composite or Fiber Reinforced Composite is defined as a polymer (plastic) matrix, either thermoset or thermoplastic, that is reinforced (combined) with a fiber or other reinforcing material with a sufficient aspect ratio (length to thickness) to provide a discernable reinforcing function in one or more directions.

FRP composites are different from traditional construction materials such as steel or aluminum. FRP composites are anisotropic (properties only apparent in the direction of the applied load) whereas steel or aluminum is isotropic (uniform properties in all directions, independent of applied load).

Therefore, FRP composite properties are directional, meaning that the best mechanical properties are in the direction of the fiber placement. Composites are similar to reinforced concrete where the rebar is embedded in an isotropic matrix called concrete.

Thursday, December 4, 2008

The Role of Reinforcement and Matrix

The role of the Reinforcement is to CARRY THE LOAD in the composite system.

While the Matrix performs two major roles
1) To transfer the load to the reinforcement
2) To protect the reinforcement against abrasion and adversed environmental effects

Picture of matrix material in contact with the reinforcement in a composite system