Pierna

Solo disponible en BuenasTareas
  • Páginas : 10 (2486 palabras )
  • Descarga(s) : 0
  • Publicado : 21 de agosto de 2012
Leer documento completo
Vista previa del texto
RJTA Vol. 8 No. 2 2004

Weave Structure and the Skewness of Woven Fabric
A. Alamdar-Yazdi
Department of Textile Engineering, the University of Yazd, Yazd, Iran
E-mail: aalamdar@yazduni.ac.ir
Phone: 0098-351-8240843
Fax: 0098-351-8210699
0098-351-5252818

ABSTRACT
This experimental work demonstrates the effect of weave structure on the skewness of
fabric. The work shows that thedistortion of gray woven fabrics depends upon the
behaviour of the floats (which is related to the factor of weave) at the state of relaxation.
Nine, 50-metre rolls of woven fabrics in different weaves were produced. The fabrics were
marked in a rectangular form (1.70 metres in width and one metre in length) at the weaving
machine. After 24 hours of relaxation, the new shapes and sizes wererecorded. The
deformations of the fabrics due to the weave structures were different. The shapes of almost
all of the samples were changed to Trapezium, even though they differed in size. This
experimental work showed that, of the nine different weaves, the 3/3 twill weave had the
highest skewness and the Zigzag twill structures the lowest, proving that the type of weave
affects the deformation and,as a result, the skewness of the fabric.
Key words: Skewness, weave structure, twill weave, Fabric deformation

1.

Skewness in woven fabric is a condition where the
warp and weft yarns, although straight, are not at
right angles to each other (McIntyre, 1995)
(Fig. 1).

Introduction

Woven fabrics are constructed with lengthwise and
crosswise yarns interlaced at right angles.

Fig.1. Woven fabric skewness and its measurement

speed across the width of the fabric. In the
finishing process, skewness often results when wet
fabric is attached to chain-driven tentering frames
and run through a heated oven. Fabric will become
skewed if it is attached to the frames so that the
filling yarns are pulled off the 90-degree alignment
or if the chains on either side move atdifferent
speeds. However, skewness takes place through the
mechanism of fabric shear as the warp and filling

Skewness creates difficulties during tailoring,
sewing, and the process of three-dimensional
forming. Garments made from skewed fabric may
behave differently on each part of the body and, as
a result,cause the fabric to lose its shape.
The problem can occur in the warping, weaving,and finishing processes. The main cause at any step
of the finishing process is the variation in running
28

RJTA Vol. 8 No. 2 2004

straightening devices are used during the finishing
processes (Ridel, 1986).

yarns rotate at intersections from a right angle
position to form an obtuse or acute angle (Carolyn
et al., 1995).

As Fig. 1 shows, skewness is expressed as a directdistance (AB in Fig. 1) or as a percentage of the
width of the fabric: 100 (AB/BC) (Kaswell, 1963).

During the process of forming fabric (yarn, made
into woven fabric –warping and weaving–), the
problem can occur because of variations in tension
across the width of the warp beam (Ghavamnia,
1998). (In the case of sectional warping, an
improper slope or tension applied to each band of
warp cancause skewness.) On a weaving machine
skewness can also be caused by uneven let-off or
take-up speeds, causing unequal tension on the two
sides of the cloth being woven (Alavi and
Abdolmotalebi, 1999).

A search of the literature revealed that there have
been few studies on skewness in woven fabrics. No
studies were found on the causes and effects of the
problem for woven fabrics. Theonly work that was
found was on the effect of skewness on the drape
(Carolyn, et al. 1995).

2.
2.1

In this work the deformation of the fabric during
relaxation (after the weaving tension is released)
is considered, and the distortion of the weave
structure due to contraction (which will result in
perfect skewness (not the bow)) is studied.

Reed count (dents/10cm.)
Warp /dent
Warp...
tracking img