Fabric Structure and Design: Twill weave

By

Md Vaseem Chavhan Assistant Professor VIGNAN University

wasim.chavhan@yahoo.com

Introduction to twill

1) Concept:

The most characteristic of twill is that they have diagonal lines on the cloth.

The basic characteristics of twill weaves are :

(i) They form diagonal lines from one selvedge to

another.

(ii) More ends per unit area and picks per unit area

than plain cloth.

(iii) Less binding points than plain cloth

(iv) Better cover than plain weave

(v) More cloth thickness and mass per unit area.

Factors determining the twill

The following factors determine the relative prominence of twill weaves

(i) Nature of the yarn

(ii) Nature of the weave

(iii) The warp and weft threads/inch, and

(iv) The relative direction of twill and yarn twist

Influence of the twist of the yarn

• The twill fabric clearness and prominence of the twill lines are accentuated if their direction is opposite to the direction of twist

• If, however, the lines of a twill are require to show indistinct, the twill should run the same as the direction of twist.

Twill weaves fabrics

• Generally 2/1 twill in Jeans, warp or weft face boot linings, corset i.e fit garment.

• Generally 2/2 twill in blanket, sheeting

• Generally 3/1 twill in a drill fabric

• Generally 2/2 twill, warp face Gabaridin, rainproof overcoating

• Generally 3/1 twill in Denim, close fitting trousers,skirts etc

• etc

Designation of twill

2up, 2down; 2- and 2-, 2/2

more convineaintly

Relative firmness • The intersecting of threads gives the cloth firmness, and the

more frequent the intersections are the firmer the cloth is

Classification of twill weave

The above types of twills are further subclassified as:

(a) Warp face twills

(b) Weft face twills

(c) Warp and weft face twills

The twill weaves are produced in a wide variety of forms. They are however

classified broadly into important categories, namely :

(i) Ordinary or continuous twills

(ii) Zig zag , pointed or wavy twills

(iii) Rearranged twills such as satin/sateen weaves and corkscrew weaves

(iv) Combination twills

(v) Broken twills

(vi) Figured and other related twill weaves

Continuous Twill

Continuous twill

In these types of twills the warp thread floats over all the picks in a repeat except one pick. The minimum repeat size required is 3.

In these weaves the weft thread floats over the warp on all picks in a repeat except one.

In these types of twills the warp and weft floats may be equal or unequal.

Warp faced twill Weft faced twill Balanced & unbalanced twill

2/1, 3/1, 4/1, 5/1 1/2, 1/3, 1/4, 1/5 2/2, 3/3, 4/4, 5/5

Zig zag , pointed

or

wavy twills

• One of the simplest forms of modified twill is the waved twill achieved by reversing the direction of the twill at suitable intervals.

• The reversal can occur either upon a warp end(horizontal wave), or upon a weft pick (vertical wave).

• Horizontal effect economically produced in point draft using few heals on tappets.

• Vertical effect required dobby due to large number of picks in lifting plan.

How to construct vertical angled twill:

• First, the size (repeat) of the angle needs to

be determined.

RO=

• Where KO is the number of warp threads

after which the sign of shift changes.

22 OK

2. Weave drawn:

22

13

■ ■ ■

■

■ ■ ■

■

■ ■ ■

■

■

■ ■ ■

■

■ ■ ■

■

■ ■ ■

■

■

■ ■

■ ■

■

■

■

■

■ ■

■

■ ■ ■ ■ ■ ■

■

■ ■ ■

■

■ ■ ■

■ ■

■ ■ ■

Example: construct the angled twill on

the base twill

(1) Calculating the repeat:

Ro=2Ko-2 Ry=Ryb

(2) Drawing the ends from 1 to Ko

based on the basic twill

(3) Drawing the others based on

the changing sign of shift.

3. Weaving plan

• Pointed draft is used for the angle twill.

■ ■ ■

■

■ ■ ■

■

■ ■ ■

■

■ ■ ■

■ ■

■ ■ ■

■

■ ■ ■

■

■

■ ■

■ ■

■

■

Notes:

• Short warp or weft floats should be used so as to

avoid overlong floats when the weave is reversed.

• Vertical angled twill weaves are achieved with

point draft.

• Horizontal angled twills are achieved with straight

draft.

Herringbone twills

• The twill line of herringbone weaves is broken at predetermined intervals to continue in the opposite direction (reversal of direction).

• Cuts or breaks occur in the fabric where warp floats are exchanged for weft floats and vice versa.

• Clean cuts avoid long floats that can occur in angled weaves.

Weave drawn • Herringbone weave construction is similar to

angled twill except the repeat calculation.

• Example: construct a herringbone weave based

on weave twill , KO = 6.

2

2

• Owning to principle of opposing, at point of reversal

• A warp lift with weft lift (and vice-versa)

• Warp face with weft face in reverse direction

• Herringbone weave sample:

Broken Twill

• Broken twill is

formed by a break in

the continuation of

the twill line at

predetermined

intervals.

“●”(lifts) indicates the sequence of the

rearranged ends or picks.

C continuous twill C1 Half broken C2 frequent breaking E2 brak size (3) and actual weave size (8) Total ends= 24

1. Braking and reversing of sequence

2. Enter and Skip (or filling and skip) • Most suitable number to skip is one less than half

number of threads in repeat

• For 2/2 twill,skip1(4/2 - 1), Fig A,B and C

• For 3/3 twill,skip2(6/2 - 1), Fig D and E

• The number of threads in the repeat of design ascertained by noting position of weave distant from each other

• Fig F Repeat size of final design is as follows

8(repeat of original twill)/1(downward) x 4(outward) = 32

3. Cut and Join Small mat or cord effects can be made either to cut with the twill, or to join it in continuation.

Elongated Twill

The angle of twill

The angle of twill is the angle between the diagonal twill line and an imaginary horizontal line or axis parallel to the weft.

This angle is dependent on the ratio between the ends/inch and picks/inch in

the cloth.

When the warp ends/inch is equal to the weft picks/inch, the twill angle

will be 45°.

When the warp ends/inch exceeds the weft picks/inch the twill angle

will be an obtuse angle i.e., >45° (high angle or steep twill).

When the weft picks/inch exceeds the warp ends/inch, the twill angle

will be an acute angle i.e., <45° (low angle or flat twill).

1) The density ratio changes the

fabric appearance. (See Fig.3.14)

• Tan α= / = Po/Py

• The inclination angle depends on the density ratio:

• Po = Py; tan α= 1; α=450

• Po＜Py; tan α＜ 1; α< 450

• Po＞Py; tan α＞ 1; α> 450

yp

1

op

1

See Fig.3.14

2) The shift changes the fabric appearance.

(1) Calculate the repeats,

Where, ROB is basic twill repeats.

(2) Draw the first end according to the formula of the basic twill

(3) Draw the other ends according to the same formula, but with the

changed shift

3.Selecting or Rearranging

4. Adding to base mark

In Forgoing methods may result in loose fabric it is preferred to construct starting with bas line

In Steep twill, the warp should be as a rule, show more prominently on the surface than a weft and vice versa in flat twill. Considering reverse convention in figure U and W

Combination of twill waves

Placing the warp threads of one weaves

among the threads of the other weave.

• Here we can see in Fig.4.8, the ends at B in red are

placed among that of A in black, so crepe weave at C is

produced. • Notes: More often the ratios of the basic weave repeats are 1:1, otherwise, the

repeats of the crepe weave are the LCM of PyA & PyB and POA &POB

C

Fig. 4.8

Different possible weave by changing Position

•A=B, c.f 6 (6,6),c.m 6 6 possible weave with(12 X 6) •J=2I, c.f 4 (8,4), c. m. 8 4 possible weave with (8 X 16) ,pick wise •O=O, c.f 8, (8,8), c.m 8 But only 4 possible weave can Form with (16 X 8)

Combination of flat and Step twills

Large fancy twill from small twills

Q(5),R(4), c.m 20 (5,4) Possible weave with(40 X 40). Bothway

Thank You!!!