dependent on the wettability of the fibres and resin properties, like viscosity and gel point. Typically, the three cycles of temperature, pressure and vacuum are studied experimentally to obtain the best combination of the three parameters. Polymerization in an industrial oven is similar but without pressure control. It is less expensive and therefore used for all those laminates which do not need to have the very highest mechanical strength and stiffness properties. Moreover, as industrial ovens are, in general, bigger than autoclaves, they are used for components with non-standard dimensions. Polymerization with matched-die moulding Polymerization with matched-die moulding is used for plane or simple-geometry laminates and can include a vacuum pump and an electric or hydraulic heat source. It is made of a press with male and female moulds that close to form a gap with the shape of the component, the width of which is regulated to control the thickness of the part. The press can not apply hydrostatic pressure as in an autoclave, but only a vertical one. Matched-die moulding allows a very high degree of dimensional control, a good surface finish on both surfaces, and reasonable production rates but, on the other hand, it may allow fibre misalignment and it is very expensive. Problems As Meola et al. pointed out in Infrared thermography in the evaluation of aerospace composite materials, "Several different types of defects may occur during the fabrication of composites, the most common being fibre/play misalignment, broken fibres, resin cracks or transversal ply cracks, voids, porosity, slag inclusions, nonuniform fibre/resin volume ratio, disbonded interlaminar regions, kissing bonds, incorrect cure and mechanical damage around machined holes and/or cuts." Also, three main problems related to cutting polymerized composite materials must be considered. The first is that reinforcement fibers are abrasive, hence traditional cutting tools are not suitable, as their lives would be very short and their blunt edges would damage the materials. The second is that composite materials have low thermal conductivity, which can cause heat accumulations and deformations. The last is that composite materials tend to delaminate when cut, therefore it is necessary to consider this when choosing a cutting method. References Composite materials Fibre-reinforced polymers Composite material fabrication techniques