![]() ![]() The tension directly affects both fibre volume fraction and void content and, in turn, influences the strength and stiffness of the composite part. The tension required is dependent on the type of fibre, the part diameter and the winding pattern selected. The fibers are supplied on creels and it is normal to have fiber tensioners (closed-loop controlled servo-driven "dancers") in the feed line. The fibres are impregnated with resin (by immersion, or by passing over a resin-wetted drum, or by injection into the die) before being led to a feed eye where a controlled band-width is set prior to positioning on the mandrel.įiber tension is critical to the operation of a filament winding machine. ![]() While filament winding machine design varies with part geometry, the basic filament winding process concept is described in the following schematic. Fibre tows are passed through a resin bath before being wound onto a mandrel in a variety of orientations, controlled by the fibre feeding mechanism, and rate of rotation of the mandrel. This process is primarily used for hollow, generally circular or oval sectioned components, such as pipes and tanks. Spray layup is also in limited use for obtaining fiberglass splash from transfer tools. Spray layup is being used to join back-up structures to composite face sheets on composite tools. This technology produces low specific strength structures which usually do not belong on the end product. Spray layup has very little application in aerospace. The part is then cured, cooled and removed from the reusable mold. ![]() Wood, foam or other core material may then be added, and a secondary spray-up layer imbeds the core between the laminates (sandwich construction). Workers roll out the spray-up to compact the laminate. The resin and glass may be applied separately or simultaneously "chopped" in a combined stream from a chopper gun. Spray-up is an open-molding composites fabrication process where resin and reinforcements are sprayed onto a mold. Most of aircraft composite parts, boat hulls and decks, RV components, truck cabs and fenders, wind-turbine blades etc. epoxy, polyester, vinylester, phenolic.įibers: Any. Fiber content up to 70 percent has been reported. The applied vacuum compacts the preform and helps the resin to penetrate and wet-out the fiber preform. Vacuum-assisted resin transfer molding (VARTM) and infusion molding systems are gaining favor with open-mold processors wanting to cut volatile organic compounds emissions. Each ply is sprayed with Catalyzed resin (1000 to 1500 cps) and the resin is worked into the fiber with brushes and rollers to wet-out and compact the laminate.įiber content can be increased by up to 50 percent by curing the part in a vacuum bag, using 2 psi to 14 psi vacuum pressure and cure temperatures under 350∫ F. In hand lay-up processing, fiberglass (typically E-glass) continuous strand mat and/or other fabrics such as woven roving are manually placed in the mold. Using low-styrene and suppressed-styrene resins, fillers and high-volume/low-pressure spray guns or pressure-fed resin roller applicators helps reduce emissions of volatile organic compounds. A chopper gun chops roving (usually E-glass) directly into the resin spray, so that all materials are simultaneously applied to the mold. In the spray-up process, after the gel coat cures, catalyzed resin (usually polyester or vinyl ester at 500 cps to 1000 cps viscosity) is sprayed into the mold, along with chopped fiberglass. It then may be cured in a heated oven at about 120∫ F. In a typical open mold application, the mold is first waxed and sprayed with gel coat. Hand layup is an open contact molding in one-sided molds are the lowest-cost and most common processes for making fiberglass composite products and is the most common method of producing composites parts in the U.S. ![]()
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