Transcript Document

8.2 Warp Pile
Introduction:
1: Method of weaving
2: Cutting (arrows)
3: Development of pile weaves
Introduction:

Warp pile fabric contains three systems of warp and two systems
of weft: face end, back end and pile end; face pick and back pick,
where face weave and back weave are called ground weave.
See Fig. 8.6:
Fig. 8.6
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The face and back fabrics are stitched on the loom by
means of pile warp. The two fabrics are separated by
cutting the pile threads.
From Fig. 8.6 we can see a clear difference in warp
crimp between ground weave and pile warp, so a
separate weaver’s beam is necessary in weaving warp
pile.
The representative fabric of warp pile is velvet.
1. Method of weaving

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Two ground cloths are produced with a certain space between them.
The distance from face to back fabric determines the required height
of the pile. Pile ends interlace alternately with face and back picks.
According to different shedding and picking during the weaving, two
categories are classified as following :
A
Fig. 8.7 sketch of warp pile weaving
B
1. Single shedding. See Fig. 8.7 (A) (show flash)
Face cloth is formed by face ends and picks,
Back cloth is formed by back ends and picks
2. Double shedding. See Fig. 8.7 (B) (show flash)
Face and back cloths are formed simultaneously,
identically interlacing ends are drawn into two mail
healds.
Face and back picks are inserted in pairs.
2. Cutting (arrows)

The two fabrics are separated by cutting the pile
threads in the middle during the weaving process.
Cutting takes place when the race is put back and
the pile ends are taut. Each cloth is to be wound
on separately.
F = face
B = back
P = pile
3. Development of pile
weaves
1) Selection of the ground weave. For velvet, 1/1 plain is
preferable. Sometimes, 2/2 weft rib and 2/1 varied rib
are selected. The density of the piles, distribution of the
piles need to be considered during selection.
2) Determine the ways of binding type. V-type is
preferable compared with W-type.
3) Determine the ratio of the ground and pile warp
4) A section diagram is helpful to the weave construction.
Example 1:

Construct the warp pile weave, the parameters
are given below:
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V type binding
Warp: 1 pile end―1 face―1 back―1 pile―1 face―1
back end
Weft: 1 face―1 back pick.
Ground: plain weave for face and back weaves.
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Answer to example 1:
／
 Determine the repeats
and draw the outline
★
★
★
 Draw the longitudinal-section
Transfer the weave
★
／×
■
／×
■
／
Notes to the key:
 In the figure:
a, b --- pile ends
Final weave:
Example 2: get familiar with
the following warp piles:
 V-type structure, one pile system
Warp: 1 pile ---- 1 face end ---- 1 back ---- 1 face ---- 1 back end for ground
Weft: 1 face pick ---- 1 back pick
Ground : plain weave for both face and back cloths
Pile: interlaces alternately with face and back picks
 Fast or W pile binding, one pile system
Warp : 1 pile end ---- 1 face --- 1 back --- 1 face --- 1 back end for ground
Weft : 3 face picks --- 3 back picks
Ground : rib for face and back cloth
Pile :interlaces alternately with 3 face and 3 back picks.
 V-type binding, two pile systems
Warp: 1 face end A ---- 1 face ---- 1 back end
1 pile end B ----1 face ---- 1 back end
Weft : 1 face ---- 1 back pick
Ground : plain weave for both face and back cloth
Pile: both pile ends interlace alternately with face and back picks
Applications:

Warp pile fabrics possess full piles. Soft hand,
good elastic recovery, good crease resistance,
thermal insulation and delicate colour. Widely
used for lady and children cloth, drapery, seats
covers, package cloth for some valuables.
Home works:
According to the longitudinal-sections, indicate the required
parameters and draw the weaves.
1)binding types; 2) arrangement; 3) ground weaves; 4)
weaves
Ⅰ
Ⅱ
Ⅲ
8.3 Terry pile
Introduction:
These fabrics of such weaves are characterized
by formation of loops which are raised above the
surface of the fabric either on one or both sides.
The fabrics possess a relatively high level of wet
ability, hygroscopic, and soft handle. They are
used for toweling as well as for bath mats, bed
covers and dress.
The principles of loops
formation (show flash)
1. Special beating up – Terry pile motion .
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“short beating” and “fast beating”
2. Special warp threads
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The ground warp has a higher tension; and the
pile warp have a loose tension.
3. Special weaves and coordination
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Resistance of the beating-up should be
minimum.
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The pile warp is firmly held by ground weave.
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After last beating-up, the last weft can not
move reversely.
Fig. 8.9 Analysis of three picks terry pile
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First ,resistance of the beating-up:
See Fig. 8.9 (A), (B), (C). At (A), the ground ends interlace with
weft two times; and at (B), (C) one time. So weave (A) has a
bigger resistance than (B) and (C). (B), (C) are preferable.
 Second, holding force:
(B), (C) have same gripping force to the pile warp. At (C), weft 1
and 2, hold the pile warp; at (B) weft 2, 3 hold the pile warp. At (B),
the loops can not be evenness. (C) is the best .
 Third, reverse motion of the last pick:
At the diagram (A) the weft 3 and next repeat weft 1 are in the same
fell. So after the reed goes back, the pick 3 will be moved reversely.
At diagram (B), pick 3 can be moved, but it is not serious.
The loop would change as the pick removes. At
diagram (C), even the pick 3 can be removed, but the
gripping force come from weft 1, 2, so it will not affect
the pile loop and the loop are kept constantly.
According to the analysis above, (C) is the best weave for
3-picks terry fabric.
Example 1: single sided pile
(A)
(B)
( C)
Fig.8.10 single sided terry pile
Longitudinal-section
Example 2: double sided pile
(A)
(B)
(C)
Double sided terry pile
Longitudinal-section
Homework:
Describe the principles of terry pile formation.
Main points:
(1) fast beating and short beating.
(2) loose tension warp, higher tension warp.
(3) Weave possess three requirements.