Manufacturing method for Composites - Pultrusion
The process of Pultrusion is utilised for the manufacture of the components which have a constant cross-sectional shape ( beams, rods, tubes etc.),and continuous lengths. In Pultrusion process, thermosetting resins are first used to impregnate continuous fiberrovings or tows; then they are pulled through a steel die which then provides the required shape to the stock and also sets the ratio resin/fibre. After this, the stock is then passed through a curing die which is precision machined so that it can give the final shape to it. This die is also heated to start curing of the resin matrix. Then the stock is drawn through the dies with the help of a pulling device. This step also determines the production speed as well. Glass, Aramid fibres and carbon are primary reinforcements materials, usually added in concentrations of approximately ranging from 40 and 70 vol%. The matrix materials commonly used in this process are polyesters, vinyl esters, and epoxy resins.
Diagram of the pultrusion process.
Continuous roll of reinforced fibers/woven fiber mat
Resin soaked fiber
Die and heat source
Finished hardened fiber reinforced polymer