Woven Cloth Construction Study Notes

The physical properties and performance characteristics of woven fabrics are affected by:
  - (a) The characteristics of the warp and the weft yarns
  - (b) The spacing and interlacing of yarns (design and construction)
  - (c) Modifications produced by finishing

Influence of Fibres on Yarns:
Fibres used in producing yarn significantly influence its characteristics.
Physical Properties: Length, fineness, weight, appearance, softness, texture
Performance Characteristics: Strength, moisture absorption, abrasion resistance, crease recovery
Yarn Characteristics Affected by Fibre Characteristics:
  - Yarn Strength:
    - Influenced by fiber strength, length, fineness, number per cross-section, and twist level.
  - Yarn Fineness:
    - Affected by fiber fineness, length, and twist level.
  - Yarn Lustre:
    - Determined by fiber surface characteristics and twist level.
  - Surface Integrity (Hairiness and Abrasion Resistance):
    - Dependent on length, fineness, and twist level.

Sett: The spacing of ends and picks in woven cloth, expressed as threads per cm.
  - Square Sett: Ends and picks per cm are approximately equal.
  - Unbalanced Sett: Significant differences between ends and picks.
  - Open Sett Structure: Presence of voids between yarns, influential in applications regarding comfort, thermal insulation efficiency, flammability, etc.
Fabric Structure Factors Influencing Performance Characteristics:
- Number of warp and weft yarns per cm, amount of twist, yarn size, and type of yarn structure.
Types of Weave Structures:
- Ranging from plain weave, twill, satin to complex interlacings.
- Variations affect strength, tear, abrasion, crease, drape, and weight.
Warp and Weft Visibility:
- Spacing warp tightly leads to a warp-faced textile.
- If the warp is widely spaced, the weft may cover it, forming a weft-faced textile.

Examples of Finishing Modifications:
  - Mercerisation: Improves yarn lustre.
  - Crease-resistant resin finish: Affects tear resistance and handle.
  - Calendering and Coating: Impacts air permeability and thickness.
  - Raising and Brushing: Enhance insulation properties and softness.

Definitions:
- Fibres: Made from natural (cotton, flax) and synthetic materials (e.g., polyester).
- Filaments: Long, continuous yarns, such as silk and certain synthetics.
Yarn Types:
  - Continuous-Filament Yarns (c.f.): Made from endless filaments; less dependent on twist for strength, tends to be smoother and more lustrous.
    - Types: Flat, textured, bi-component, tape.
  - Spun Yarns: Made from short fibres, require twist for strength, tend to be irregular.

Bulk Density: The component of yarn density is air pockets created during yarn formation.
- Packing fraction: Indicates air spaces enclosed by fibers affecting yarn elasticity and strength.
- Strong correlation with fabric characteristics like comfort and thermal insulation.

Factors Influencing Strength:
- Fiber strength, length, fineness, twist level, number of fibers.
Relationships: Longer fibers generally yield stronger yarns in terms of cohesion; twist affects breaking strength.

Defined by Yarn Count or Size:
- Related to linear density or mass per length used in defining both fibre and yarn.
Diameter Relationship: Finer yarns lead to different fabric characteristics like thickness and handle.

Definitions:
- Twist Direction: “S” or “Z” direction based on spin.
- Twist Level: Measured by turns per unit length.
Influence on Fabric Appearance:
Different angles of twist lead to different visual and tactile properties in the final fabric.

Parameters:
- Abrasion Resistance: Defined through cycles of wear until yarn failure.
- Hairiness: The degree of fibers protruding from the yarn, affecting both aesthetics and performance.

Definition: The number of warp and weft threads per square inch. High counts indicate greater fabric quality, lower shrinkage, and longer wear.

Definition: Represents how yarn bends during interlacing, affecting fabric thickness, softness, and resistance to wear.
- Relation to Tension in Fabric: Even tensions yield more balanced crimp ratios across yarns.

Types:
- Treatments include bleaching, dyeing, polishing, and anti-wrinkling.
- Each treatment affects fabric properties such as strength, care, and comfort.

Definitions and Characteristics:
- Complex, fancy, or novelty yarns create different appearances by altering typical manufacture.
- Single/Two-ply, Slub, Thick-and-thin, Flock yarns, Bouclé, and Ratiné yarns each provide unique texture and looks.
Strength Variation: Mixed strength characteristics based on built-in irregularities.

Influences on Physical and Performance Properties:
- Very different fabric characteristics affected by yarn choice.
Conclusions: Yarns have to be studied deeply to optimize final product performance.

Characteristics include maximum interlacements and strong fabrics (light, medium, or heavy weights).

Diagonal lines create visually appealing effects, varying from simple balanced to unbalanced twill.

Importance of Finishing: Determines fabric applications and suitability for use, including specialized finishes for durability, aesthetics, and maintenance ease.