Faculty Overview

• Department: Textile Science and Apparel Technology

• Programme: BSc Textile Science

• Qualification Code: BASTX1

• Subject: Product Engineering 2

• Subject Code: PROE201

• Semester: 1

• Year: 2026

Woven Cloth Construction

• Physical Properties and Performance Characteristics

  • Influenced by:

    1. Characteristics of warp and weft yarns

    2. Spacing and interlacing of yarns

    3. Modifications produced by finishing

1. Characteristics of Warp and Weft Yarns

• Fibre Influence:

  • Fibres used in yarn production significantly influence yarn characteristics.

  • Key physical properties affecting yarn include:

    • Length

    • Fineness

    • Weight

    • Appearance

    • Softness

    • Texture

  • Key performance characteristics affecting yarn include:

    • Strength

    • Moisture absorption

    • Abrasion resistance

    • Crease recovery

• Yarn Characteristics Affected by Fibre:

  • Yarn Strength:

    • Influenced by fibre strength, fibre length, fibre fineness, number of fibres per cross-section, and twist level.

  • Yarn Fineness:

    • Affected by fibre fineness, fibre length, and twist level.

  • Yarn Lustre:

    • Determined by fibre surface characteristics and level of twist.

  • Surface Integrity (Hairiness and Abrasion Resistance):

    • Depends on fibre length, fineness, and twist level.

2. Spacing and Interlacing of Yarns

• Sett Definition:

  • Refers to spacing of ends and picks in woven cloth, expressed as threads per cm.

  • Affects properties such as strength, tear, abrasion, crease, drape, weight, etc.

• Sett Types:

  • Square Sett: Ends and picks per cm are approximately equal.

  • Unbalanced Sett: Significant differences between ends and picks per cm.

  • Open Sett: Voids between warp and weft yarns, influencing air permeability, comfort, flammability, and thermal insulation.

3. Modifications Produced by Finishing

• Modifications include:

  • Mercerisation: Improves lustre.

  • Crease-resistant Resin Finish: Affects tear resistance and handle.

  • Calendering: Affects air permeability and thickness.

  • Coating: Influences fabric properties.

  • Brushing and Raising: Impact insulation properties and softness.

Important Aspects in Woven Fabric Production

1. Fibres and Filaments

   • Basis for all fabrics: natural and synthetic.

   • Types of fibres:

     • Natural Fibres: Cotton, flax, wool from animals.

     • Synthetics: Continuous filaments requiring no spinning before fabric manufacture.

2. Yarns

   • Continuous-Filament Yarns (c.f.):

     • Consist of substantially endless filaments, depend on twist for coherence.

       • Sub-groups include:

         • Flat Yarns: Standard filament yarns.

         • Textured Yarns: Modified to introduce distortions for increased bulk.

         • Bicomponent Yarns: Produced from two components with individual characteristics.

         • Tape/Split Film Yarns: Created by cutting thin film into strips.

   • Spun Yarns:

     • Made from short, variable-length fibres, depend on inter-fibre cohesion for strength.

     • Has lower tensile strength and will vary in appearance.

3. Yarn Density

   • Yarn density influenced by packing fraction (air pockets + fibres).

   • High packing fraction leads to stiffness; low packing fraction lacks integrity.

   • Impacts: Dimensional stability, strength, extensibility, flexibility, air permeability.

4. Yarn Strength and Fineness

   • Yarn Strength Factors:

     • Fibre characteristics: strength, length, fineness, number per cross-section, twist level.

     • Breaking strength, elongation, elastic modulus, resistance to abrasion considered.

   • Yarn Fineneess:

     • Typically described as yarn count, size, influenced by diameter and fineness.

5. Yarn Twist

• Definition of Twist: Spiral turns applied to yarn to hold fibres together.

• Parameters of Twist:

  1. Twist Direction: S or Z direction.

  2. Twist Level: Turns/unit length (t.p.i).

  3. Twist Factor: Accounts for yarn radius and twist level.

  4. Impact of twist on fabric appearance and stability.

1. Yarn Surface Integrity

   • Defined by:
     a. Abrasion Resistance
     - Measured based on cycles required to break yarn.
     b. Hairiness
     - Protruding fibers counted using shadow or length methods.

2. Thread Count

   • Number of warp and weft threads per sq. inch, higher counts signify better quality.

3. Crimp

   • Defined as the ratio of length difference to length of fabric.

   • Affects fabric characteristics including cover and softness.

4. Finishing of Fabrics

• Critical for fabric suitability and value.

• Finishing Techniques Include:

  • Bleaching, dyeing, calendering, anti-microbial, anti-static treatments.

  • Crease Resistance: Chemical treatments can improve fabric handling, but may reduce tear resistance.

1. Calendering

   • Process of feeding cloth through heated cylinders affects fabric softness, appearance, density, and shine.

2. Moiré Effect

   • Wavy watermark pattern produced by pressing together two layers of fabric.

Complex Yarns

• Definition: Yarns modified for irregular size/color or appearance.

• Types of Complex Yarns:

  1. Slub Yarns: Bulky areas produced through uneven twisting, soft and fluffy sections.

  2. Thick-and-Thin Yarns: Different pressures during spinning create areas of varying thickness.

  3. Flock Yarns: Small tufts of fibre inserted at intervals for textures.

  4. Bouclé Yarns: Characterised by loops that project from the yarn.

  5. Ratiné and Gimp Yarns: Similar to bouclé, with closely spaced loops.

  6. Loop Yarns: Characterised by loops held in place with a binder yarn, used in many textile applications.

Compound Yarns

• Compound (Composite) Yarns: Comprise two components; core and covering.

  • Covered Yarns: Yarns are wrapped with a covering around the central core, can include elastomeric materials for improved properties.

  • Core-Spun Yarns: Yarns with a staple or filament cover surrounding a continuous filament core, offering combined strength and aesthetics.

• Applications include stretch fabrics, protective clothing, and aesthetics.

Yarn Doubling

• Involves twisting two or more yarns together to form a compound yarn.

• Advantages: Improves yarn regularity, strength, and extension, particularly useful in worsted or woollen yarns.

Texturizing Yarns

• Yarns processed for added crimp (coils, loops), enhances warmth, bulk, and comfort.

• Common forms of texturizing include:

  • False Twist: Results in coil-type crimp.

  • Stuffer Box: Introduces random crimp.

  • Airjet: Produces a loop type appearance.

Conclusion

• Understanding woven fabric construction and yarn characteristics is critical for the production and selection of textiles suited for various applications.

• Acknowledge the importance of yarn structure and treatment processes in determining the final properties of woven fabrics.