Introduction
Pultrusion is the only continuous manufacturing process for obtaining high quality composite profile, with high mechanical properties. Pultruded products are compose of high performance fibres (glass, carbon, aramid) embedded in a polymer matrix.The process is characterized by:
-Wide choice of reinforcement and resins
-Low scrap rates
-Complex shape and unlimited length
-Low labor content
-High raw material conversion efficiency
-Consistent quality
-Attractive cost
Process description
Pultrusion is a continuous process of manufacturing of composite materials with constant cross-section whereby reinforcing fibers are pulled through a resin, possibly followed by a separate preforming system, and into a heated die, where the resin undergoes polymerization. Many resin types may be used in pultrusion including polyester, polyurethane, vinylester and epoxy.The process begin when reinforcing fibres in the form of continuous rovings or mats are pulled from a series of creels and fed continuously trough a guiding system into a bath,where they are impregnated with the desired liquid matrix resin.The resin impregnated fibres are preformed to the shape which matches that of the desired finished profile.This composite material entering the heated curing die. On die exit ,the composite material haws been changed by polymerisation into a fully shaped and solid profile. The profile cools in ambient or forced air.The product emerges from the puller mechanism and is cut to the required lengths by a diamond tipped flying cutoff saw.
Reinforcement types
When choosing reinforcements, three characteristics must be considered:
1- the fibre type (glass fibre, aramid and carbon)
2- the form (roving strands, mat & fabrics)
3- the orientation.
The glass fibre is the most used reinforcement.
Resins typs
Unsaturated Polyester resins
Epoxy Resins
Vinyl Ester Resins
Other resins
Matrix
The composite properties are determined by the properties of resin matrix.
Characteristics
* corrosion resistant
* high mechanical strength
* low weight
* chemical resistant
* electrical and thermal insulating
* temperature resistant
* low thermal expansion
* anti-magnetic, no sparks
* electromagnetic transparent
* custom colours
* easy to machine
* low maintenance
* reduced transport costs
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