Elongated Twill Weave and Combined Twill Weave
Md Sohanur Rahman Sobuj
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Elongated Twill Weave and Combined Twill Weave :
Elongated twill :
Elongated twill is constructed by advancing the points of intersection two or more threads in one direction and one thread in the other direction. The angle of twill line is determined by the step number (the rate of advancement from one interlacing point to the next). The angle of elongated twill is either below 450 or above 450.
Elongated twill can be constructed in two different ways:
i) By using step number
ii) By selecting a base line
By using step number: If the step no of elongated is two; then if we take only odd number of warp threads from the basic twill for weave plan, the step number of the produced design automatically become two.
By selecting a base line: Here at first a step number is to be selected. In such a way that the repeat of base line become divisible by that step number. For example, repeat of base line: 10÷2=5 ends repeat, 15÷3=5 ends repeat.etc.
There are two types of elongated twill:
❶ Warp way elongated twill
❷ Weft way elongated twill
Warp way elongated twill:
Step upward at least two instead of one in each warp.
The angle of warp way elongated twill is above 450.
When the repeat size of basic twill is even number, then the no. of warp yarn in a repeat size of elongated twill is half of the no. of warp yarn of basic twill and no. of weft yarn is same as the no. of weft yarn of basic twill.
When the repeat size of basic twill is odd number then the repeat size of elongated twill is same as basic twill.
Straight draft is used.
Weft way elongated twill:
Step downward at least two instead of one in each weft.
The angle of warp way elongated twill is below 450
When the repeat size of basic twill is even number, then the no. of weft yarn in a repeat size of elongated twill is half of the no. of weft yarn of basic twill and no. of warp yarn is same as the no. of warp yarn of basic twill.
When the repeat size of basic twill is odd number then the repeat size of elongated twill is same as basic twill.
Straight draft is used.
Combined Twill
It is formed by combination two regular twill and arranging them alternately with each others.
It is capable of producing compact and firm textures.
Types:
i) Warp way combined twill
ii) Weft way combined twill
The repeat size of two basic twill weave may be equal or different.
In warp way combined twill, divided draft is used. The heald shafts are divided into two groups, first groups control the first design and second groups controls the second design.
In weft way combined twill, straight draft is used.
Repeat size calculation:
a) If the repeat sizes of two basic twill are same, then
Warp way combination:
Warp yarns of new design=Warp yarns of basic twill x 2
Weft yarns of new design=Weft yarns of basic twill
Weft way combination:
Warp yarns of new design=Warp yarns of basic twill
Weft yarns of new design=Weft yarns of basic twill x 2
b) If the repeat sizes of two basic twill are not same, then
Warp way combination:
Warp yarns of new design=LCM of no. warp yarns of basic twill x 2
Weft yarns of new design=LCM of no. weft yarns of basic twill
Weft way combination:
Warp yarns of new design=LCM of no. warp yarns of basic twill
Weft yarns of new design=LCM of no. weft yarns of basic twill x 2
Note: LCM means lowest common multiple
(5431)
Md Sohanur Rahman Sobuj
Latest posts by Md Sohanur Rahman Sobuj (see all)
- Thermal Properties of Polymers - April 26, 2019
- Frictional Properties - September 15, 2018
- Torsional Properties of Textile Materials - August 30, 2018
