3.2.5 Angled twills 1. Concept The angled twill is constructed by changing the sign of shift from plus to minus after a given number of threads. (Recalling that reinforced twill is constructed by extending floats; elongated twill by changing the shift; curved twill by using an alternating shift)

The appearance of the fabric like an angle, so it is called angled twill. See Fig.3.21. Angled twill weave can be divided into vertical angled twill and horizontal angled twill.

Vertical angled twill The vertical angled twill has two diagonal lines which are symmetrical about a predetermined warp thread.

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.

2. Weave drawn: ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ (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. ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Example: construct the angled twill on the base twill ■ ■ ■ ■ ■ ■ ■ ■ ■

3. Weaving plan Pointed draft is used for the angle twill. ■ ■ ■ ■ ■ ■

4. Applications Angled twills are widely used for lady’s fabric, woolen coat, sheet, various tweeds. Sample: vertical angled twill

Applications: Horizontal angled 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.

3.2.6 Herringbone and broken twills Concept The twill line of herringbone weaves is broken at predetermined intervals to continue in the opposite 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. See Fig.3.24. The appearance of the fabric likes herring’s bone, so it is called herringbone.

Weave drawn Example: construct a herringbone weave based Herringbone weave construction is similar to angled twill except the repeat calculation. Example: construct a herringbone weave based on weave twill , KO = 6.

Broken twills Concept Broken twill is formed by a break in the continuation of the twill line at predetermined intervals. See Fig. 3.27

Fig.3.27 various broken twills: “●”(lifts) indicates the sequence of the rearranged ends or picks.

Construction of broken weave The broken twill is constructed by changing the sequence of the ends or picks.

Weaving plan Broken draft is suitable for herringbone and broken twills. Applications They are used for herringbone tweeds, sheets, and various decorative fabrics.

Herringbone weave sample:

3.2.7 Diamond weaves 1. Concept Diamond designs are based on angled twill and can be considered as vertical angled twill combines with horizontal angled twill. (See Fig. 3.29) Fig.3.29 diamond weave

2. Weave drawn (1) Choosing base weave: (2) Determining Ko, Ky: (the size of the pattern) (3) Drawing the basic part according to base weave and Ko, Ky. (4) Drawing the angled twill. (5) Drawing the other part by taking the weft thread Ky as the axes of symmetry.

Example: Drawing the diamond weave, base weave is 2/2↗ twill, KO=4, Ky=4. ◇ ◇ ◇ ◇ ◇ ◇ ◇ ■ ■ ▲ ■ ■ ▲ ▲ ■ ■ ▲ ■ ■

Diamond fabric samples:

Diaper weaves Diaper designs are based on herringbone twill combining with a horizontal herringbone twill. See Fig.3.30 Diamond and diaper weaves are suitable for pointed draft and they are widely used for lady`s cloth, sheet and woollen fabrics. Fig.3.30 Diaper weave

Homework: 1. Drawing the following angled twills, and adding the weaving plan: 2. Drawing the following Herringbone weaves: 3. Drawing the diamond weave, the basic weave is 2/2↗ ,KO=10, Ky=10