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off coils and rolls which are then guided through a resin bath or resin impregnation
system. Resin can also be injected directly into the mould in some pultrusion
systems. The resin is always a thermosetting resin like Unsaturated Polyester
resins, epoxy resins, Vinyl Ester Resins, polyesters resin, phenolic resins or
methalcrylate sometimes combined with fillers, catalysts, and pigments.
The fiber filaments thoroughly saturated with the resin mixture moves into pre-
forming fixtures where the section is partially pre-shaped & excess resin is
removed. It is then passed through a heated die, may have several zones of
temperature through-out its length, which will cure the thermosetting resin. The
profile that exits the die is now a cured pultruded Fiber Reinforced Polymer (FRP)
composite. Either caterpillar take-off units or hydraulic clamps are used to pull the
composite through the pultrusion die on a continuous basis and at its end is cut to
the desired length by cutoff saw.
Advantages of Pultrusion: Provides high performance composites products
which are safe, strong, light weight, corrosion free, electrical and thermal
insulators, show exceptional dimensional stability and easily fit to assembly.
Applications: off-shore platforms, ladders, cable trays, window frames, insulated
roll up panel doors, automotive bumpers, scrubber components, chemical plant
hand railings, gratings, walkways & bridges, pipe supports, window latch supports,
Cooling tower ancillaries, Flooring supports, others
Types of extrusion machines: Basically, an extruder machine consists of a feed
screw, barrel and temperature controller. But the design and features of the machine
depend of several other factors like the type of material to be extruded and the
design of the product. A profusion of plastic extrusion machines are available in the
market, some of them being:
lHDPE/RPVC/PPR pipe Extrusion line l
Plastic Sheet Extrusion Machine
lBlown Film Plant lPP TQ Film Plant
lMulti layer Blown Film Plant lCast Film Line
lRaffia Tape Stretching Line lAir Bubble Sheet Plant
lPP/HDPE Box Strapping Plant lPET Box Strapping Plant
lExtrusion Coating Lamination Plant lPP/HDPE/PET Monofilament plant
lSynthetic String Plant (Sutli Plant) lPET Recycling Plant
TYPES OF EXTRUSION DIE:
Die is an opening of particular shape in metal plate that allows plasticized material to
flow through itself and provide its shape to the plastic. Dies are machined from high-

quality alloy tool steel, is hardened and hard chrome plated to avoid erosion and
corrosion. The die opening controls the thickness and width of the extruded part and
also compensate for effects of shrinkage when a melt re-solidifies. Dies are heated
for uniform flow control and few such as sheet die are equipped to adjust range of

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