Jacquard shedding

However, a simpler solution is to change not the material or the pattern, but simply the number of warp yarns used during construction. For example, a shuttle loom equipped with a jacquard shedding system controlled by... 

Another type of shell three-dimensional woven textile was suggested in 1929. A combination of Jacquard shed formation and shuttle weft insertion creates a flat woven fabric with areas of double and single layers (Lippert, 1929). Depending on the coti-tour of the double-layer area, this part of fabric can be cut and unfolded after weaving, for example, to become a hat geometry (Figure 4.4). 

Figure 4.4 Woven hat shapes by using Jacquard shedding and shuttle weft insertion (Lippert, 1929).

The best-known application offering the largest market quantities is the OPW airbag. Jacquard shedding is combined with shuttleless weft insertion for driver and... 

The shedding mechanism is one of the primary motions of a loom. A Jacquard shedding mechanism is used for weaving 3D preforms because the individual warp fibers are controlled independently by Jacquard harness cords. A 3D fabric and preforms can be woven on a 2D conventional rapier loom, but there is a fabric thickness limitation when using any conventional 2D loom. 

Using a Jacquard head instead a dobby for shedding opens the possibility to create user-defined curved contours of hollow zones. Curved tubes, fittings having other than 90° angles between the intersecting tubes, helmet and hat shells, as well as similar types of shapes can be created with this method. One of the most spectacular applications is a reinforcement fabric of missile noses (Rothe and Wiedemann, 1963). 

The 2D conventional loom is modified to weave various 3D woven preforms. What kind of modification(s) should be carried out depends on the nature of preforms to be produced. The take-up and shedding motions are modified in many ways along with other tools that are also installed. Modified looms are used to produce thick panels, contour materials, polar materials, and complex 3D preforms. An unlimited number of 3D preforms and complex shapes can be woven on a modified loom with electronic Jacquard. Figure 9.60 shows a narrow fabric shuttle loom weaving a 50-mm-thick carbon panel. An orthogonal weave has been used with a dead pick motion so thatX, Y, and Z fibers are perpendicular to each other. 

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