Manufacturing pultrusion

The preceding short process description is based on the most basic—but also most common—pultrusion setup. There are several variations to the theme, however, and many details were intentionally left out. In the following, the process is described in some detail and different processing and machinery options are briefly discussed. The variety in machinery solutions reflect the fact that many, perhaps most, pultrusion machines used to be designed and built inhouse by the pultruder rather than by a dedicated machinery manufacturer. There... 

Because pultrusion is a truly continuous manufacturing method, composites may be produced in any length that can be handled small, flexible cross-section composites may even be wound onto drums endlessly. Nevertheless, the composite is normally cut, in the simplest case with a hand-held hack saw, but more commonly to predetermined lengths with an automatic saw that follows the moving composite during cutting. 

The predominant advantage of pultrusion as a manufacturing method for thermoset composites is the low production cost, which is closely related to the reasonably high... 

Glass, carbon, and aramid fibers are used as unidirectional or fabric mat reinforcements, with E-glass/ polyester being the most commonly used system. The limitation of pultrusion is that only constant cross-section parts can be fabricated. However, a variety of hollow and solid profiles of any length can be manufactured. 

The important process-control parameters in pultrusion manufacturing are the pull speed, fibre volume fraction, viscosity, temperature settings for die heating zones, and the preform plate area ratio (compaction ratio). Key process variables include die pressure and temperature. 

The processes that can be used for the manufacture of WPC products are compounding, extrusion, injection molding and pultrusion. Drying ofwood is an important prerequisite of WPC production since... 

Joshi S. The pultrusion process in polymer matrix composites. In Advani S, Hsiao K-T, editors. Manufacturing techniques for polymer matrix composites (PMCs). Cambridge (UK) Woodhead Publishing Limited 2012. 

The cyanate ester monomers are available from low-viscosity liquids to meltable solids. Ciba-Geigy produces a series of cyanate esters imder the trademark AroCy L-10. Cyanate esters are used in manufacturing structural composites by filament winding, resin transfer molding, and pultrusion. 

If the filaments are not wound onto a mandrel but simply gathered into relatively large bundles and led slowly into a heated consolidation zone, emerging from a die partly or completely cured, the primitive essentials of pultrusion are present (Fig. 2.3(b)). This process began as the thermosetting resin equivalent of extrusion, that is, it was a continuous operation for manufacturing profiles, such as rod and channels. The method has been extended to fibre reinforced thermoplastics. 

The pultrusion process has a low labour requirement and it can manufacture large amounts of profile with high glass-to-resin ratio, using continuous roving at a competitive cost. 

Manufacturing methods for composites vary from manual to fully automated processes, whereby the latter have better quality control than the former. Wet layup, pultrusion, and filament winding are all discussed in some detail, while other techniques such as pull-winding, resin transfer moulding, vacuum bag moulding, and injection moulding are left to specialized composite materials texts. 

Pultrusion—Process for the manufacture of composite profiles by pulling layers of fibrous materials, impregnated with a synthetic resin, through a heated die, thus forming the ultimate shape of the profile. Used for the manufacture of rods, tubes and structural shapes of constant cross-section. 

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