What is autoclave vacuum bag?

Pre-impregnated fibre is applied to the mould either by hand or machine. The fibre area is covered with a rubber or plastic bag and the air removed using a vacuum pump. Further pressure and increased temperature are applied by placing the mould in an oven or autoclave and the resin is cured. Under the applied pressure, the layers of prepreg are fused together and any excess resin removed. The vacuum allows for voids to be collapsed producing a laminate with a very low void content. The release mechanism consists of a special film applied to each surface which allows air and excess resin to pass through it.

The main advantage of this manufacturing method is that components of high quality with excellent properties can be produced. This is still the favoured method of the aerospace industry. With the use of the vacuum bagging and autoclave, the health and safety issues from emissions are reduced. However, the process is labour intensive and requires extensive capital equipment cost. To control the resin and void content adequately, especially for thicker parts, requires highly skilled labour.

Some of the key points of this method include: