Advanced Methods
As well as the techniques described on this website such as wet lay up with compression tape or vacuum bagging, carbon fibre fabric (whether wet laid, resin infused, pre-preg or even applied by filament winding) can be compressed by other means. These include an inflation bladder, expanding core, compression mould.
Standard fabrication techniques can be adapted to suit a specific project, depending on the final part's requirements.
An inflation bladder is placed inside a part before it is cured and inflated to compress the fabric into a closed mould. The part can either be laid up in two or more open mould parts and the bladder added after lay up, or, more commonly, the fabric is laid directly onto the bladder which is then placed inside a mould before inflation and cure.
We use this technique for most closed structures, for example making bike frame front triangles in one piece. Click here to learn more about what we can do.
A simple inflation bladder made from polyethene sheet.
An expanding core operates in the same way as an inflation bladder, being a solid mandrel onto which fabric is laid. The core is made from a material that expands sufficiently at high temperatures (like those required to cure pre-preg material) so as to exert pressure on the inside of the moulds which are closed around it.
A solid expanding core onto which carbon is laid before the assembly is placed inside a closing mould.
A compression mould is a simple idea which requires some precision execution to produce high quality parts. Essentially the carbon is squeezed between different parts of a precision mould.
As well as these techniques there is an almost endless range of processes that can be deployed depending on the part being produced. The essential ingredients remain the same however, they are ensuring that the carbon fibre fabric is laid in a mould according to a lay up schedule, with resin added either before or during fabrication, before the part is compressed into the mould to compact the various layers and produce a single composite part.
Pieces of a basic compression mould which is closed on all sides to compress carbon onto a mandrel (darker green part).
We hope the information in this website has given you an introduction to some of the more common composite fabrication techniques and that you now have a better understanding of the processes involved. There is plenty more detailed and specific information elsewhere on the internet to help you if you want to give it a go. Always remember to read the safety information for the products you are using and take steps to protect yourself.
If you have a specific project in mind but you're not sure you are able to complete some (or all) of the steps, contact us and see how we can help. You can click here for more information about our custom projects.