Roll forming of composite sheets

In their molten states, thermoplastic polymers behave like incompressible viscous fluids. By simply melting the matrix polymer and applying moderate forces, complex geometries can often be formed, even in the presence of fibers. Furthermore, it is interesting to note that polypropylene remains deformable over a wide temperature window while cooling from its melt temperature, before it recrystallizes. In this thermal region, it exhibits nonlinear viscoelastic fluid properties which are not 

Mander, S.J., Panton, S.M., Dykes, R.J. and Bhattacharyya, D. (1997) Roll forming of sheet materials, in Composite Sheet Forming, Chap. 12, (ed. D. Bhattacharyya), Elsevier, Amsterdam, pp. 473-516. 

Mander, S.J., Bhattacharyya, D. and Collins, I.F. (1995) Roll forming of fiber reinforced composite sheet, in Proceeding of the 10th International Conference on Composite Materials, III (eds. A. Poursartip and K. Street), Woodhead Publishing, Cambridge, pp. 413-420. 

Cogswell, F.N. (1992) Thermoplastic Aromatic Polymer Composites, Butterworth-Heinemann, Oxford. 

and Gutowski, T.G. (1991) Laps and gaps in thermoplastic composites processing. Composites Manuf., 2, 69-78. 

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In roll forming, a sheet of material is formed into some desired shape by feeding it through successive pairs of rolls, arranged normally in tandem. It is demonstrated in the chapter Roll forming of composite sheets that this process is also a very suitable method for producing, e.g. thin-walled U- or Z-profiles out of Twintex material. 

Mander S J, Panton S M, Dykes R J and Bhattacharyya D (1997) Roll Forming of Sheet Materials, in Composite Sheet Forming (Ed. Bhattacharyya, D), vol. 11, Composite Materials Series, Elsevier Science Publishers, Amsterdam, The Netherlands, pp. 473-516,... 

The differences in chemical composition are accompanied by differences in the morphology of the tobermorite gel. Spicular or cigar-shaped rolled sheets are formed in the normal plain hydrated cement paste, whilst in the presence of calcium chloride, thin crumpled sheets or foils are formed. It has been suggested [16] that either the high lime content or adsorbed chloride prevents rolling of the sheets. 

Plastic Flooring. Plastic flooring is marketed either as tile or sheet flooring. Tile is supplied as pieces usually 30.5 x 30.5 cm with a thickness of 0.16—0.32 cm and is usually homogeneous in composition. Sheet flooring, on the other hand, is produced in roll form 1.8, 2.7,3.7 and 4.6 m wide (2- and 4-m in Europe), and generally consists of a plastic upper component on a fibrous backing. 

Figure 2 shows a schematic diagram of a possible set-up for roll forming CFRT sheets. The composite sheets are pulled off a number of rolls and fed into a consolidation process from which the consolidated sheet moves directly into the first set of rollers in the roll-forming mill. At each roll station, the strip is progressively formed into its appropriate shape and emerges in its finished form on the right-hand side of Figure 2. During this process, it is possible to put the strip into tension by increasing the roller rotational speed at successive roll stations. Extra roll...

Ceramic-glass composite materials may be used to economically fabricate very complex multilayer interconnection structures. The materials in powder form are mixed with an organic binder, a plasticizer, and a solvent and formed into a slurry by ball or roll milling. The slurry is forced under a doctor blade and dried to form a thin sheet, referred to as green tape or greensheet. Further processing depends on the type of material. There are three basic classes of materials high temperature cofired ceramic (HTCC), low temperature cofired ceramic (LTCC), and aluminum nitride. 

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