Analysis Of The Methods Of Frp Manufacturing

GFRP first developed and being produce in the mid 1930’s was merely used for buildings and construction parts. GFRP are used increasingly in the automotive industry. One of the example of the uses of GFRP is the use of GFRP for manufacturing truck bonnets. Truck bonnets used to be manufactured using the traditional steel and spot welded construction. There are many methods to manufacture FRP:

• Hand lay-up
• Spray up method
• Filament winding
• Matched die moulding
• Pultrusion
• Resin transfer moulding
• Reaction injection moulding.

Hand lay-up method

Hand lay-up method, this method is relatively cheap because there is only few equipments used, suitable for making small to large composites product. It is also the simplest method to mold composite. Hand lay-up method usually works by applying resin into the fibre on the mold. First the mold are applied with coating gel so it has a high quality surface then the resin are applied to the fibre using paint roller, brushing, spraying or poured. Rollers are used to remove the air entrapped between the resin and fibre, then optionally fiberglass layers can also be added to build a laminate layer.

Spray up method

Spray up method is similar to hand lay-up method, but the difference is that instead of pouring the resin to the fibre in the mold, spray gun is used. The spray gun consist of resin catalyst pot, air pressurized resin, and fibre which the fibre are chopped inside the chopper part of the gun. Advantages of using this method is the low cost involved in this method. It is quick to form the composite and relatively inexpensive tools are used. Also, by using spray up method, fibre orientation cannot be controlled thus making it inconsistent between composites produced using this method.

Filament winding

Filament winding method is used to produce hollow, circular or oval components. Composites are produced by winding the fibre and resin filament on a rotating mandrel and a moving carriage. Glass or carbon fibre are usually used to produce the composite by using this method. First, the fibres are passed through in the resin making the fibre submerged fully in the resin as they are being wounded onto the mandrel. Then, the mandrel is cured either by heat. After it is cured, the mandrel is removed and the composites are produced. Filament winding method is widely used in automotive industry like making rims, poles and pressure vessels.

Matched die moulding

Matched die moulding also called as compression moulding it is the common method to use to produce both thermoset and thermoplastic material. The process starts by heating the mould cavity and the material then, the material places in the cavity and pressure is applied for the material to shape like the mould cavity, while the temperature and force applied being controlled until the materials are cured. This process is typically used to mass produce a specific product. This process can also be used to produce thermoplastic with embedded fibre. It also has the lowest cost, lower waste than other moulding process. But some of the disadvantages of this method is that it is not very consistent for the product produced.

Pultrusion

Pultrusion is a process of making composite with constant cross section continuously with specific properties. There are several equipment required in pultrusion process. Continuos roll of fibres, tension roller, resin injector, heating chamber and pulling mechanism are required. Pultrusion method can produce product with consistent and precision. This method is also automated, making less labour required. Disadvantages of this material is that the material produce are restricted, only specific shape can be produced.

Resin transfer moulding

Resin transfer moulding is moulding method where the material is enclosed. Unlike compression moulding which the material is open to fill into the moulding cavity. First, the mould cavity is coated with gel. The material before being mould may be liquid or preheated solid, which is then loaded into a pot. Then the material is forced from the pot to the cavity by the use of plunger. Then the product curing can be controlled for optimal properties. This method produces a good surface finish. But on the other side the equipment used to run this method are expensive.