Glass fiber rovings

Spray-up Popular system with reinforced plastic production. An air spray gun includes a roller cutter that chops usually glass fiber rovings to a controlled short length before being blown in a random pattern (manually or automatically) onto a surface of the mold simultaneously the gun sprays catalyzed TS polyester plastic. The chopped fibers are plastic coated as they exit the gun s nozzle. The resulting, rather fluffy, RP mass is consolidated with serrated rollers to squeeze out air and reduce or eliminate voids. A closed mold... 

Wet Lay-Up Process. Formulations are impregnated by hand or sprayed into fibers that are in the form of woven, knitted, stitched, or bonded fabrics. This is usually accomplished by rollers or brushes. Spray-up is a partly mechanized version of the hand lay-up process. The thermoset precursor is applied by means of a spray gun to the mold surface simultaneously with the chopped glass-fiber roving. Laminates are left to cure under standard atmospheric conditions. 

Figure 5.4 Flow of glass fiber rovings traveling through a plenum machine...

The process can combine conventional glass fiber roving, aramid, or carbon fiber tows with TPs, most commonly polyethylene terephthalate (PET) and nylon (polyamide/PA). Other plastics used include polyphenylene sulphide (PPS), styrene-maleic anhydride (SMA), high-density polyethylene (HDPE), and polypropylene (PP). The TPs can take the form of pellets, chips, chunks, or shreds, and as the process uses hot-melt injection, no solvents or two-part systems are involved. Additives such as colorants and fillers can be used as required. 

Figure 7.27 lexural fatigue data of woven glass fiber roving/epoxy RPs... 

Mat GMT is produced by means of needle-punching of glass fiber rovings. The design of the needle bed has a major influence on both the quality of the needle-punching and the subsequent flow properties (Fig. 31). 

Typically, in an SMC composition, chopped glass fiber roving (18-75 mm long) is used, and its content can vary fi om about 20-40 wt%. In a BMC composition, shorter glass fiber (6-12 mm. long) is used at 15-20 wt%. In both the SMC and BMC compositions, about 40-60 wt% of an inorganic filler such as calcium carbonate (3 pm) is additionally used, primarily to lower the cost of the composites but also to improve the flame retardancy and other physical properties. 

Composite Reinforcements, Ltd - http // www.composite-reinforcements.co.uk/ United Kingdom, distributor of glass fiber rovings, fabrics, and chopped strand mats... 

Fiberex, Ltd - http //www.fiberex.com/ Canada, boron- and fiuoride-free E-CR glass fiber rovings for composite reinforcement applications... 

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