INTRODUCTION
- Pultrusion process is the type of closed mould processes.
- It is used for producing fiber reinforcement plastic of constant cross section such as I-beam, tube, pipes etc.
- The above figure shows that Pultrusion process.
- It consists of roller, tank which containing plastic resin, heated die and soon.
WORKING
- Fibres are drawn from spools through uncured resin bath for impregnation.
- Then impregnated fibres are first fed into a pre-forming box which gives appropriate orientation to the fibres.
- These oriented fibres are then fed into a heated steel die, where polymerisation and curing takes place, and also determines the cross section of composite stock.
- After that pulling operation.(continuous length of consent cross-section can be drawn through die.
Reinforcement used in Pultrusion
- E-Glass, S-Glass /Carbon /Graphite/Aramid reinforcement are used.The forms either roving or mat or fibres.
Resins used
in Pultrusion
- The resin should have low viscosities (500cps) and also should have ability to cure quickly.Some resin are---
- Polyester
- Vinyl ester resin etc.
Advantages
- High production rate of “finished parts”.
- High material usage.
- Complex thin walled shapes can be fabricated.
Disadvantages
- Cross section must be uniform.
- Difficult to maintain tight tolerances.
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