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FIBERGLASS REINFORCEMENT* 7 Dennis J. Vaughan 7.1 INTRODUCTION The history of glass is ancient, but its engi- neering scientific development is recent. Glass was first produced some 4000 years ago, probably in Egypt in the furnaces used to produce pottery. Its first application was as a form of adornment in jewelry and as added decoration to vases and drinking vessels. The use of glass in fiber form dates back to the early seventeenth century when the Venetians utilized it to create specialized gowns. However, commercial fiberglass did not become a reality until in 1939 the joint research efforts of Owen-Illinois and Corning Glass Works, resulted in the formation of Owens-Corning Fiberglas Corporation. Textile fiberglass has now grown into a multi-million dollar industry. Glass fiber can be obtained as a continuous fiber on staple or discontinuous fiber. Both forms are made by the same manufacturing process until the fiber drawing operation. 7.2 FIBERGLASS PRODUCTION The production of glass fibers starts with the dry mixing of silica sand and limestone, boric acid and a number of other products such as clay, coal and fluorspar. These materials are melted in a high-refractory furnace, the temper- ature of the melt being dependent on the glass composition, but is generally about 1260°C Handbook of Composites. Edited by S.T. Peters. Published in 1998 by Chapman & Hall, London. ISBN 0 412 54020 7 (2300°F). The molten glass then flows directly to the fiber-drawing furnace in a direct melt flow process (Fig. 7.1) or into a marble making machine. These marbles can be sorted and can eventually be remelted and drawn into fibers. Continuous glass fibers are produced when molten glass from the fiber-drawing furnace is gravity fed through numerous tiny openings in a platinum alloy tank called a bushing (Fig. 7.2). The droplets of molten glass that extrude from each of the bushing’s openings (Fig. 7.3) are gathered together, mechanically attenuated to the correct dimensions, passed through a water spray and over a revolving belt that applies a protective and lubricating coating known as a size or binder. The fibers are then gathered together in a suitably shaped shoe to form a bundle called a strand which is wound onto a core at approximately 190 km/h (120 mile/h). This package of fibers is then dried or conditioned prior to further processing and eventually sold as a continu- ous filament yarn. Staple fibers are produced by passing a jet of air across the openings at the base of the bush- ing, which pulls individual fibers of approximately 2040 cm (8-15 in) long from the molten glass that is extruding from each open- ing. These filaments are collected on a rotating vacuum drum, sprayed with size and gathered into a strand. This package of filaments is again conditioned or dried prior to processing into a specific product for further use.
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This note was uploaded on 03/16/2010 for the course MECHANICAL ME765401 taught by Professor Prof.sulis during the Spring '10 term at Institut Teknologi Bandung.

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