Braiding Processes

RSINFCRCEMENT TYPES Filaments. Bovtrgy Wb an Fj ncs. Braiding PROCESSES. 

Nonwovens is a general term used to denote fibrous products that are made without using the weaving, knitting or braiding processes described above. 

The sheath strands are also twisted from yarn. They are braided into a cylindrical sheath, around the core. The braiding process (Fig. 15.5) is analogous to a maypole dance. As the clockwise dancers pass in and out of the anticlockwise dancer, their ribbons braid around the pole. There are between 24 (half in clockwise and half anticlockwise) and 44 strands in the rope sheath. Manufacturers may quote the number of bobbins, from which the strands are unwound. A large number means the strands are finer. The bobbins transfer from rotor to rotor, so they make circuits of the core. 

Figure 21.42 shows a schematic view of 3-D tape made by the braiding process. 

Figure 21.42 Schematic view of 3-D tape made by the braiding process. Source Reprinted with permission from Bums RL, Manufacturing and design of carbon-carbon composites, Buckley JD, Edie ED eds., Carbon-Carbon Materials and Composites, Noyes Publications, Park Ridge, 197-222, 1992. Copyright 1992, William Andrew Publishing.

Fabric crimp n. The angulation induced between a yam and woven fabric via the weaving or braiding process. Vincenti R (ed)... 

Du, G.W., Popper, P., 1994. Analysis of a circular braiding process for complex shapess. J. Text. Inst. 85, 316-337. 

A Cartesian braid process on a rectangular loom setup and a braiding cycle are shown in Figure 7.4. However, the Cartesian braiding may also be performed on a circular loom setup. In this case, the tracks move in a circumferential direction and the columns in a radial direction. Figure 7.5 shows a schematic and a photo of the circular track-and-column braider. 

Multistep braiding is an extension of the four-step braiding process. By allowing for individual control of track-and-column displacement, strong yam architectural versatility may be achieved (Kostar and Chou, 1994). 

The track-and-column braiding process has been used to produce braids with a solid, rectangular cross section. The production of solid braids with more complex crossshape geometry can be achieved through juxtaposition of multiple braids with rectangular cross sections. Additional fibre placements within the cross section allow certain yams to braid within specific area of the cross section only to produce a hybrid composite (Kostar and Chou, 2002 Ko et ah, 1989 Kamiya et ah, 2000). 

For adjacent braid groups, a peripheral yam of one braid group may be a yam of another braid group. Thus, this yam participates in the braiding process of both braid groups and is called shared yam. In Figure 7.9, the peripheral yams as well as the shared yams, marked by o and x , are depicted. 

The noninterlaced yams must be cut away after the braiding process to give the braided stmcture its final geometry. The removal of the yams reduces mechanical... 

Figure 7.23 shows solid braids with various solid cross-section geometries. These braid structures have been developed based on a simulation of the Ist-generation braiding process developed at AFML at the University of British Columbia. 

This chapter aims to describe the development of fully automatable track-and-column and hexagonal braiding processes to produce tubular, bifurcated stmctures. 

Tensile tests (NF-EN-ISO 2062) were conducted on 20 commingled yam specimens in order to ensure their compatibility with the load tension applied during the braiding process. The results are given in Table 16.1. Tensile properties are almost exclusively brought to the composite by the glass reinforcement. 

Eebel Christoph, Brand Michael, Drechsler Klaus. Effects of fiber damage on the efficiency of the braiding process. Leuven (Belgium) TexComp-11 2013. 

Schematic of pull-braiding process (Michaeli and Juerss, 1996). 

It is reported that no visible damage to the nanotube yams is imparted by the braiding process and the 3-D braids are very fine, extremely flexible, hold sufficient load, and are well suited for the use in any other textile formation process, or directly as reinforcement for composites. The reported elastic and strength properties of carbon nanotube composites so far are rather low in comparison with conventional continuous carbon fiber composites. It is believed that the properties can be substantially improved if the processing methods and stmctures are optimized [191]. 

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