40207_19 - TABLE ROLLING OF COMPOSITE TUBES J ohn T. K a m...

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TABLE ROLLING OF COMPOSITE TUBES 19 John T. Kame and Jerome S. Berg 19.1 INTRODUCTION in table rolled tube manufacture. In the field of composites fabrication table rolling is a major technique for utilizing pre- impregnated fibrous tapes in flag or pennant form for tubular structures. The individual flags become part of the total wall thickness by rolling the flags around a mandrel. The hard mandrel provides the support during cure and defines the inside dimensions of the tube. Table rolling is utilized to fabricate a variety of products including straight tubes usually under 7.62cm (3in) in diameter and up to 3.66 m (12 ft) long and small diameter tapered tubes such as fishing rods, golf shafts and ski poles. Flags may consist of a wide variety of fibers oriented either longitudinally (along the axis of the tube) or offset at a bias angle, hence the terms ’longitudinal and bias flags’. The resin content (RC) and the fiber areal weight (FAW) of the prepreg define the ply thickness. Since external molds are seldom used for table rolled tubes, a variety of polymer compaction tapes are used to apply an external pressure. These tapes provide the external pressure nec- essary to debulk and prevent flag unravelling before cure and to provide some heat driven compaction during cure. The most common resin used to coat the fibers is the epoxy blend family, which is for- mulated for specific product purposes. The resin and fiber are combined and advanced slightly to a selected ’tack‘ (stickiness) level. This fiber and resin combination is called ’prepreg’. Prepreg surface tack has an impor- tant adhesive quality in table rolling which permits composite flags to adhere to one another or the mandrel without slipping dur- ing the table rolling operation. Prepreg is offered by specification of resin type and roll width. FAW from 130-160 g/m2 and RC from 30-36% are common in table rolling. Higher modulus fibers favor a lighter FAW to ease rolling. The epoxy in prepreg is catalyzed, so care must be exercised in follow- ing the prepreg vendor’s storage and handling recommendations. Freezer storage can extend the shelf life; therefore, the material generally arrives on a freezer truck. Because air and moisture are detrimental to the surface tack, it is important to cut and consume the flags as soon as possible after opening and unrolling the prepreg. Dry and low tack prepreg can influence and aggravate flag wrinkles and ply slippage, leading to voids and dimensional problems. Address tack with the prepreg supplier to find a suitable resin formulation for the table roller’s manufacturing environment. equipment and tooling suppliers commonly utilized in table rolling is presented in Table 19.1 at the end of this chapter. 19.1.1 FIBERS AND RESIN Carbon fiber form 234 MP~ (34 msi) to 620 MP~ (90 msi), glass ’E’ or 8s’ we, aramids, polyeth- ylene and boron are some of the common fibers A Partial list of Handbook of Composites. Edited by S.T. Peters. Published in 1998 by Chapman & Hall, London. ISBN 0 412 54020
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40207_19 - TABLE ROLLING OF COMPOSITE TUBES J ohn T. K a m...

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