Lamination Vacuum assisted

A widely used method of laminate construction is by the contact moulding process or hand lay-up . In this, a layer of catalysed unreinforced resin, known as the gelcoat , is brushed or sprayed onto the mould and allowed to cure and then layers of reinforcing-fibre impregnated with resin are built up behind (Fig. 6.3). Variations of this include resin injection and vacuum-assisted resin injection in closed moulds. After removal of the cured moulding from the mould, the gelcoat forms the outer skin and as such performs the two functions of decoration and protection ... 

It is also useful for making fabric-reinforced laminates. The multiple layers of fabric are hand-laid into the mold in a predetermined pattern to optimize strength properties. Then the mold is closed, and the liquid mixture is injected to impregnate the fabric, often using vacuum assist to replace air tiioroughly by resin. The assembly is held in the press and heated until cured. The products are similar to those made by perform press molding. The process is called resin transfer molding. 

To improve the quality of the final composite by reducing the voids caused by air becoming trapped in the laminate and improving the consoUdation at the wet lay-up stage, a vacuum-assisted technique can be applied. The wet composite is sealed vdthin a bagging material and a vacuum is applied to the wet conposite using a vacuum pump to extract the enclosed air the polymer is then cured. 

Vacuum-Assisted Hydraulic Lamination. Many hydraulic presses use a vacuum to eliminate volatiles. Users of vacuum presses report a reduction of edge voiding and the ability... 

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