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Chapter Nine Gauze and Leno Weaves. 1: The concept of gauze 2: The principles of gauze weave formation 3: Gauze and leno weave examples. 1. The concept of gauze.
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Chapter Nine Gauze and Leno Weaves 1: The concept of gauze 2: The principles of gauze weave formation 3: Gauze and leno weave examples
1. The concept of gauze • These weaves differ from others in that the warp threads of one system do not run parallel or at right angles with the weft threads, but are twisted round them. • The characteristic feature of these fabrics is the spaces between the threads, which produce an open net-like structure. The weft threads are firmly held by the crossing warp threads, ensuring a uniform texture. See Fig.9.1. Fig. 9.1
The fabrics of such weaves are used for dress, curtains, decorative fabrics, and mosquito nets. • These firm open fabrics are also used for technical purposes, such as for the selvedges on the shuttle-less looms and for producing the pile yarn, so-called chenille yarn.
2. The principles of gauze weave formation 1) Some new terms: See Fig. 9.1, Fig. 9.2. Fig. 9.1 Gauze weave, plan and section (above) Fig. 9.2 Mechanism of gauze weave (right)
Doup thread ―during the weaving process, the doup thread are raised in each shed, and it passing each time under the standing threads forms a zigzag line. • Standard or regular thread ―during weaving, it remains comparatively straight. • Standard shaft ― the shaft is the same as conventional shaft. • Doup shaft ― also called lifting heald. It is described as following.
Description of doup shaft • Lifting healds L1 and L2 consist of two individual flat steel strips. Close to their centre they are connected to each other to form a resting point ( : ), which is necessary for the lifting of the doup heald D. Doup heald shanks slide between the steel strips. The bottom end of each shank is fitted with a carrying rod. These two rods are connected to each other at their end by stoppers and constitute the doup heald frame.
2) Method of weaving (see flash) • Two kinds of warp threads are necessary: standard ends and doup ends. • The doup end is drawn into the heald of the ground shaft LG and into the eyelet of the doup heald D. • The standard end is drawn into the heald of standard shaft S and between the space of the lifting healds. • The doup heald frame with the lifting heald shaft is fitted at the front.
Three shed formation: See Fig9.3 Fig.9.3 Mechanism of gauze weave of formation
① Plain shed. • Only the standard end is raised by the standard shaft S. • This plain shed forms part of the ground weave. It is used for leno weaves.
② Open shed • The doup end is raised by shafts LG and L2 with doup heald D on the right side of the standard end. Shafts L1 and S are lowered. • This open shed forms the other part of the ground weave. Standard ends have free passage between the upper part of L1 and the raised doup heald D. See Fig. 9.1, gauze weave weft ① can be woven by this shed.
③ Crossed shed. • The doup end raised by shaft L1 with doup heald D on the left hand side of the standard end. Shafts L2, LG and S are lowered. See Fig.9.1, gauze weave weft ② can be woven by this shed. • In the crossed shed position (heavy lift) the easer bar E is pulled towards the harness because the tension of doup ends must be slackened so that the threads do not have to carry excessive strain.
The gauze weave is sometimes referred to as the leno weave because it is made on a leno loom, but the true leno weave is a variation of the gauze weave which is usually formed by combining with the plain weave.
3. Gauze and leno weave examples: Development of leno structures on point paper. Diagrams on the following pages : E = easer bar; C = cross-section D = draft; W = weave R = reed; S = structure and lifting plan
Homework: 1. Understand the following terms: Standard thread, Doup thread, Standard shaft, Doup shaft Ground shaft, Leno, Open shed, Plain shed Crossed shed, Gauze, Counter leno 2. Understand the weaving process of gauze.
