It is not possible to decouple the design of materials from geometry and from the most suitable production process in the field of composite materials. Aspects to be taken into account when choosing a certain type of product are manifold:
- structural performances;
- costs;
- morphological constraints.
Therefore, several production methods of fiber reinforced materials are distinguished, in practice, by manufacturing possibilities and by the use of the finished product. Hereunder you can find the main manufacturing processes of composite materials for corporate applications:
- hand lamination;
- RTM;
- vacuum infusion;
- SMC;
- BMC;
- pultrusion.
The choice between glass fiber, carbon fiber, .. and polyester resin, epoxy resin, .. does not limit technology applied.
Hand lamination
it is used for laminating very different large pieces at a low rate production. A cheap wooden or resin die representing the negative geometric characteristics of the element is used: alternating layers of matrix and of glass fibre tissues are overlapped on it, properly oriented to the project process and to working stresses. Then the finished product is removed from the die to be finished. An example of this application is represented by hulls for boats in resinglass.
RTM (Resin Transfer Moulding)
resin injection moulding, a more or less complex process. According to the project process the fibers are arranged into the mould, previously heated, where a pressure of about 0.8 bars is generated, after it has been closed. When the internal temperature has been stabilized, the resin, under pressure, is injected and can penetrate into the small interstices. Then it is necessary to wait, until the polymerization process has been completed. This technique can be further subdivided into Light RTM, which is more simple and with the use of wooden moulds and into RTM with direct injection and with the use of aluminium moulds. An example of this application is represented by seats for public transport means.
Vacuum infusion
resin infusion moulding, a more or less complex process. The reinforcement fabric is positioned into a watertight mould, where a vacuum is created. Then the catalyzed resin is poured and settled to the bottom of the mould. This process is used for the production of medium-large sized elements, improving the product quality and reducing the labour costs.
[Coming up ‘production methods’ – page 4) 5) 6)]
