Transcript Document

UNIT Ⅱ
Compound Structure
Chapter 6 Backed weaves
Chapter 7 Multi-ply Fabrics
Chapter 8 Pile Fabrics
Chapter 9 Gauze and Leno weaves
Chapter 10 Jacquard Fabrics
Introduction:

Fundamental and combined weaves are
considered to be simple, though there are a great
variety of types and constructions. In these weaves,
only one system of warp threads are interlaced with
one system of weft threads at right angles. Due to
this, the methods of construction of these weaves
and production of fabrics of such weaves at textile
mills are quite simple.
Compound weave fabrics are of a specific
structure, therefore special methods and
mechanisms should be used in their production.
For instance:
1) blanket made from backed weaves;
2) many industrial fabric made from multi-layer weaves;
3) terry fabric made by a special mechanism;
4) pile fabrics made by a special finishing process;
5) leno weave with open structure made by using a
special heald.
Chapter Six:
Backed weaves
The principle of backing a cloth with a second series
of either weft or warp threads is to add extra weight and
warmth without interfering with the smooth surface of
the fabric. The end uses of backed cloths range from
apparel to home furnishing.
6.1 Warp backed weaves
I Concept:

These are weaves which have two systems of warp
and one system of weft. The face weave is formed by
interlacing face warp and weft, and the back weave is
formed by interlacing back warp and weft.

The system of weft plays an important role due to
interlacing with both systems of warp. The weft
threads are raised above the face warp and lowered the
back warp.
II Construction of warp
backed weaves
1) Selection of face weave and back weave

The face weave can be same as the back weave, and can
be different from the back weave, but the face weave
should be warp-faced weave such as 3/1 twill, back weave
should be weft-faced weave such as 1/3 twill.
2) Selection of the starting point in construction
of a back weave:

In order to get a better appearance of the fabric, the
backing stitches (back warp floats) should be hidden
between floats on the face.
3) Determine the ratio of the face and back
warp:

Usually the ratio is: m : n = 1:1 or m : n = 2:1.
4) Calculate the “new repeats”
5) Transfer the weaves
Transfer the face weave and back weave into one weave.

Example:
Construct a backed weave:
face weave : 3/1↗
back weave : 1/3↗
warp ratio: 1:1
1) Selection of face weave and back weave:
both weaves have been given
2) Determine the starting point:
Should meet the previous point
2, stitching float should be
covered by face warp float.
3) Determine the arrangement of the face and
back warp:
Warp ratio: 1:1
4) Calculate the repeats and outline the repeats:
The outline is drawn as :
5) Transfer the weaves
face
①
1
②
Ⅰ
③
Ⅱ
④
Ⅲ
cross-section
longitudinal section
Ⅳ
back
④
face
③
②
back
①
1
Ⅰ
Where: × indicates intersections of face warp and weft threads and ■ indicates
that of back warp and weft threads. 1,2,3 and 4 are face warp threads while
Ⅰ,Ⅱ,Ⅲ and Ⅳ are back warp threads.
Ⅲ Applications

It is widely used for making woolen and
worsted fabrics.

Notes:
Face ends are usually drawn into the front shafts.
6.2 Backed weft weaves
I Concept:
These are weaves which have two systems
of picks and one system of ends. The face
weave is formed by interlacing warp and face
weft threads. While the back is formed by
interlacing warp and back weft.
Weft faced structures are more suitable for
this method as the backing stitches can be
hidden between floats on the face.
II Construction of weft
backed weaves

The principles of the construction of backed
weft weaves are similar to warp backed weaves.
1) Selection of face weave and back weave
The face weave can be same as the back, and can differ
from that, but the face weave should be weft-faced
weave such as 1/3 twill, back weave should be warpfaced weave such as 3/1 twill.
2) Determine the stitching distribution
The correct stitching plays a very important role in the
construction. On no account must it be visible on the
face of the fabric.
3) Determine the arrangement of the face and back picks.
m : n =1:1 or m : n = 2:1.
4) Calculate the new repeats
5) Transfer the weaves
Example:

Construct a weft backed weave,
face weave: 1/3 Z twill; back weave: 3/1 Z twill ;warp ratio--1:1
A: Calculate the new repeats: Ry= LCM of
(
4 &1
4 &1
and
)(1  1)
1
1
=4×2=8
■ ■■
■
■■■
■
■■■
■
■■ ■
■
RO=LCM Rm & Rn=4
B: Indicate the face warp floats with ■ on
the face ends 1,2,3 and 4.
C: Complete the back warp floats with
■ on the corresponsive ends
Weft backed weave
Ⅲ Applications

It is widely used for blanket and woolen
fabrics.
Home works
1. Construct backed warp weaves:
(1) Face weave 3/1↗, back weave 1/3↗, arrangement of
face warp and back warp m : n=1 : 1
(2) face weave 8/5 satin, back weave 1/3↗, m : n=1 : 1.
2. Construct backed weft weaves and their cross-section
diagrams.
(1) face weave 1/3 broken twill, back weave 3/1 broken
twill, m : n=1 : 1.
(2) face weave 2/2↗, back weave 3/1↗, m : n=1 : 1.