What is a PULTRUSION..?

Pultrusion Principle

            
PULTRUSION:

There are so many process techniques to manufacture Composite FRP products. Among all Pultrusion is a manufacturing technique to producing FRP structural profiles. Pultrusion is a continuous Fiber Reinforced Plastic (FRP) process for the manufacture of products having a constant cross section, such as structural shapes, beams, channels, pipes, tubes, fishing rods, and shafts etc. Pultrusion produces profiles with extremely high fiber loading, thus pultruded products have high structural properties and process high strength to weight ratio.

The Fiberglass Pultrusion Process

Pultrusion is a manufacturing process for producing continuous lengths of FRP structural shapes. Raw materials include a liquid resin mixture (containing resin, fillers and specialized additives) and reinforcing fibers. As the name suggests, the process involves pulling these raw materials (rather than pushing as is the case in extrusion) through a heated steel forming die using a continuous pulling device. The reinforcement materials are in continuous forms such as rolls of fiberglass mat or doffs of fiberglass roving. As the reinforcements are saturated with the resin mixture (“wet-out”) in the resin impregnator and pulled through the die, the gelation (or hardening) of the resin is initiated by the heat from the die and a rigid, cured profile is formed that corresponds to the shape of the die.

While pultrusion machine design varies with part geometry, the basic pultrusion process concept is described in the following schematic.

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Pultrusion Process

Continuous fiberglass reinforcements, in the form of roving and glass mat, are fed from a creel to a resin impregnation station, to coat each fiber with a specially formulated polymer thermosetting resin mixture (wet out).

The coated fibers are assembled, by shaping guides into the preformer, which squeezes away excess resin, as the product is moving forward and gently shapes the materials prior to entering the forming and curing die, which forms the desired cross section.

Composite Pultrusion Product 

The product made from Pultrusion process has composed with reinforcements(fiberglass rovings and mats) and resin.

Fiberglass Pultusion: is an engineered tailored product that can vary with the pultruder’s ratio of glass to resins, the formula of additives to meet specific requirements.

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