3.2.10 Rearranged Twills 1. Concept Rearranging a weave means taking single thread or groups of threads from the base weave and rearranging them in a different order. See Fig. 3.36
Base twill Fig. a: Fig .a : the picks are rearranged in groups of two in sateen Fig .b :a different rearrangement in warp direction in groups of two Fig. b:
2. They are constructed as follows: • a) Select base weave. • b) Determine a plan for rearrangement. • c) Rearrange threads: ends or picks.
3. Example: • Base twill the new order of warp threads is 7,8; 5,6; 3,4; 1,2. Base twill rearranged twill in the given order
4. Applications • Many characteristic fabrics can be made by using rearranged twills due to its versatility.
3.2.11 Shaded twill • 1. Concept • The shaded twill represents a gradual transition from the twill with weft effect to warp effect, and vice versa. It is used mostly in Jacquard weaving for large-pattern fabrics. See Fig.3.37
2. Weave drawn Formulae to calculate the repeats: Ro = Rob (Rob-1 ) Ry = Ryb Where: Ro---new weave repeat; Rob---the base weave repeat.
3.3 Satin/Sateen weaves Derivatives • 1.Reinforced sateen It is constructed by using the original sateen as the base and adding overlaps. See Fig. 3.38 Adding a warp float at the right of the original one
Example • Fig. 3.39 shows a 11/8 reinforced sateen which is often used for worsted fabric called satin back gabardine. • The face of the fabric has a twill appearance and back has a satin appearance.
2. Shaded sateen • Like the shaded twill, the shaded satin represents a gradual transition from the sateen with weft effect to the satin with warp effect, and vice versa. See Fig.3.40 Ry=Ryb=5 RO=Rob(Rob-1)=5×4=20
3. Rearranged sateen/satin weaves • It can be constructed by rearranging the sequence of the picks or varying the shift. See Fig. 3.41, 3.42. Obtained from varying the shift Shifts (Sy)=4,3,2,2,3
Home work: 1. Base weave ↗, the order of warp threads is 1,2, 7,8, 13,14, 5,6, 11,12, 3,4, 9,10, draw the rearranged twills. 2. draw a shaded twill from 1/3↗ to 3/1↗.
Chapter ThreeSummary: • Derivatives of Elementary Weaves • 3.1 Plain weave derivatives. • 1. Rib weaves Warp rib weaves; Weft rib weaves • 2. Hopsack weaves
3.2 Twill weave derivatives • 1. Reinforced twill • 2. Compound twills • 3. Elongated twills • 4. Curved twills • 5. Angled twills • 6. Herringbone and broken twills • 7. Diamond and Diaper • 8. Zigzag Weaves • 9. Entwined Twills • 10. Rearranged Twills • 11. Shaded twill
3.3 Satin/Sateen weaves Derivatives • 1.Reinforced sateen • 2. Shaded sateen • 3. Rearranged sateen/satin