International Journal of Applied Glass Science--Stickel and Nagarajan Vol.3,No.2,201 Fig. 2. Glass fiber bushing(L), close-up image of bushing tips(R) Fig 3. Type 30 or direct roving() and multi-end or assembled roving(R After exiting the bushing, glass fibers are rapidly Chopped fiber applications will not be discussed in cooled, gathered, coated with sizing, and in the case of depth in this article, but fibers can also exit the bushing continuous, high-strength fibers, fed to a winder. and be fed directly to a chopper instead of a winder Winders are configured to produce direct, ready-to-use Chopped fibers are available wet or dry in a variety of rovings or an intermediary form called a forming cake. lengths. These are used as inputs for nonwoven mats After drying, direct or Type 30 rovings (pictured in and both thermoset and thermoplastic compounds. A Fig. 3)are ready for use by the composite fabricator or schematic illustrating how continuous and chopped glass fabric weaver. The glass fiber strand is typicall glass fiber reinforcements are produced is given in pulled from the inside of the Type 30 package, but it Fig. 4 can also be pulled from the outside if the fabricator has ropriate u Assembled or multi-end rovings are produced Key Product Parameters for Continuous Fibers ng several Type 30 or forming cake inputs, and can be produced with or without an interior bobbin or A combination of bi allow multiple strands or yarns to be combined into a linear density, of the bundle of filaments. These Pilana tube. Assembled rovings, shown on the right in Fig. 3, chopper pull rate controls filament diameter and tex, ngle spool, which results in higher glass application eters, filament diameter and tex, are critical to the efficiencies for the fabricator. Note the multiple strands performance of the glass fiber and thus to the compos and the smaller inside diameter of the assembled roving ite as a whole. For this reason, filament diameter and spool versus the Type 30 spool tex must be carefully monitored and controlled duringAfter exiting the bushing, glass fibers are rapidly cooled, gathered, coated with sizing, and in the case of continuous, high-strength fibers, fed to a winder. Winders are configured to produce direct, ready-to-use rovings or an intermediary form called a forming cake. After drying, direct or Type 30 rovings (pictured in Fig. 3) are ready for use by the composite fabricator or glass fabric weaver. The glass fiber strand is typically pulled from the inside of the Type 30 package, but it can also be pulled from the outside if the fabricator has the appropriate unwinding equipment. Assembled or multi-end rovings are produced using several Type 30 or forming cake inputs, and can be produced with or without an interior bobbin or tube. Assembled rovings, shown on the right in Fig. 3, allow multiple strands or yarns to be combined into a single spool, which results in higher glass application efficiencies for the fabricator. Note the multiple strands and the smaller inside diameter of the assembled roving spool versus the Type 30 spool. Chopped fiber applications will not be discussed in depth in this article, but fibers can also exit the bushing and be fed directly to a chopper instead of a winder. Chopped fibers are available wet or dry in a variety of lengths. These are used as inputs for nonwoven mats and both thermoset and thermoplastic compounds. A schematic illustrating how continuous and chopped glass fiber reinforcements are produced is given in Fig. 4. Key Product Parameters for Continuous Fibers A combination of bushing design and winder or chopper pull rate controls filament diameter and tex, or linear density, of the bundle of filaments. These param￾eters, filament diameter and tex, are critical to the performance of the glass fiber and thus to the compos￾ite as a whole. For this reason, filament diameter and tex must be carefully monitored and controlled during Fig. 2. Glass fiber bushing (L), close-up image of bushing tips (R). Fig. 3. Type 30 or direct roving (L) and multi-end or assembled roving (R). 124 International Journal of Applied Glass Science—Stickel and Nagarajan Vol. 3, No. 2, 2012