What is pultrusion? Pultrusion is a manufacturing process for producing continuous lengths of fiberglass reinforced plastic shapes, with a constant cross section. While pultrusion machines vary in design, the process is basically the same.
Let’s first start with the fiberglass reinforcement. Reels of unidirectional roving provide longitudinal tensile strength or the strength along the length of the profile. Rolls of continuous filament mat, woven roving, or stitch fabric, provide the profile with its transverse properties, or its strength across the width of the profile.
All reinforcements are first fed through preforming guides that will begin to shape the raw glass fibers into the finished profile. The glass is then pulled into a resin bath that saturates or wets out the reinforcements. The resin bath contains a mixture of resin, most commonly polyester or vinyl ester, pigments to add color, filler to enhance properties, and a catalyst to aid in curing or to turn it from a liquid to a solid. Surfacing veil is added to give the profile a resin-rich surface and enhance the appearance of the final product.
The wet out reinforcements now enter the heated pultrusion dye. The heat begins the thermosetting reaction process that cures the finished profile. The cured profile is now advanced by a caterpillar-style puller to the cut-off saw where it will be cut to its final length. The finished product is now put into inventory at one of our warehouses, sent to our state-of-the-art fabrication center for secondary processing, or crated for shipment to the customer.
Companies: Bedford Reinforced Plastics
Industries: Manufacturing (Industry)