Faculty Overview

The notes pertain to the Faculty of Applied Sciences, specifically the Department of Textile Science and Apparel Technology, under the programme of Textile Science leading to a BSc in Textile Science with the qualification code BASTX1, covering the subject of Product Engineering 2 (Subject Code: PROE201) for Semester 1 of 2026.

Woven Cloth Construction

Woven fabric characteristics and performance are influenced by multiple factors, categorized as:

(a) Characteristics of Warp and Weft Yarns

1. Fibre Influence:

   • The fibres used to produce yarn significantly affect the yarn's characteristics.
   • Physical Properties: Length, Fineness, Weight, Appearance, Softness, Texture.
   • Performance Characteristics: Strength, Moisture Absorption, Abrasion Resistance, Crease Recovery.

2. Yarn Characteristics Influenced by Fibre Characteristics:

   • Yarn Strength:
     • Affected by:
     • Fibre strength
     • Fibre length
     • Fibre fineness
     • Number of fibres per cross-section
     • Twist level
   • Yarn Fineness:
     • Influenced by fibre characteristics and twist level.
   • Yarn Lustre:
     • Dependent on fibre surface characteristics and twist level.
   • Surface Integrity:
     • Includes hairiness and abrasion resistance determined by length, fineness, and twist level.

(b) Spacing and Interlacing of Yarns (Design and Construction)

1. Sett:

   • Defined as the spacing of ends and picks in woven cloth, measured as threads per cm.
   • Impacts properties such as strength, tear, abrasion, crease, drape, and weight.

2. Types of Sett:

   • Square Sett: Ends and picks per cm are approximately equal.
   • Unbalanced Sett: Significant differences between the number of ends and picks.
   • Open Sett Structure: Characterized by voids between warp and weft yarns, impacting consumer comfort and industrial applications concerning air permeability.

3. Weave Structures:

   • From simple plain weaves to complex designs, the sequence of interlacing affects fabric properties, including strength and drape.
   • Warp-faced Textile: Achieved by closer spacing of the warp to hide weft.
   • Weft-faced Textile: Created by a spread-out warp that allows weft to cover it.

(c) Modifications from Finishing Treatments

1. Finishing Modifications Include:
   • Mercerization, crease-resistant resin, calendering, coating, anti-static finishes, water repellency.
   • Effects on properties:
     • Mercerization and calendering enhance lustre.
     • Resin finishes negatively impact tear resistance and handle.
     • Calendering and coating may reduce air permeability and thickness.
     • Raising and brushing can improve insulation and softness.

Important Aspects in Producing Woven Fabric

Fibres and Filaments

1. Types of Fibres:

   • Natural Fibres: Cotton, flax from plants, wool from animals.
   • Filaments: Silk and synthetic fibres.

2. Yarn Types Include:

   • Continuous-Filament Yarns (c.f.): Endless filaments, smooth and lustrous, do not rely on twist for strength (though twist is added).
     • Monofilament: Single, continuous extruded synthetic filaments.
     • Multifilament: Twisting together of numerous filaments.
   • Textured Yarns: Modified to increase bulk using distortions during processing.
   • Spun Yarns: Made from shorter, staple fibres requiring twist for strength. Yarns are hairy and less lustrous compared to c.f.

Yarn Density

• Defines the relationship between fibres and air in yarn structure, influencing performance characteristics.
• High Packing Fraction: Results in stiffness and strength, potentially increases skin contact.
• Low Packing Fraction: Can lack necessary surface integrity for processing.

Yarn Strength and Fineness

1. Yarn Strength:
   • Built from fibre strength, length, fineness, number per cross-section, and twist.
   • Increased twist generally enhances strength up to a limit.
2. Yarn Fineness:
   • Described by count, diameter, or thickness, affecting structural features of the fabric.
   • Coarse fibers yield bulkier yarns and impact the fabric's bending resistance.

Yarn Twist

1. Twisting Mechanism:

   • Holds the fibres together, enhancing structure.
   • Twist Direction: S and Z twists impact the appearance of fabrics.

2. Twist Parameters Include:

   • Twist level and twist factor, which influence fabric characteristics and yarn flexibility.
   • Over-twisting can reduce strength.

3. Effects on Yarn:

   • Twist increases yarn strength up to a certain threshold.
   • Affects yarn extensibility and lustre.

Characteristics of Fabric Construction

1. Thread Count:
   • Number of warp and weft threads per square inch correlates with fabric quality; higher counts indicate greater durability and wear resistance.
2. Crimp:
   • Defined as the degree of bending when yarns interlace, calculated as a ratio of length differences.
3. Finishing Techniques:
   • Various refinements like dyeing, raising, and calendering improve appearance and performance.

Complex and Fancy Yarns

1. **Types of Complex Yarns:
   • Novelty yarns that are varied in size, color, or texture. Includes slub yarns, thick-and-thin yarns, flock yarns, and bouclé yarns, each characterized by unique production methods.

Production Applications

1. Core-Spun Yarns: Yarns constructed with a core and a cover to enhance strength and appearance, used in various textile applications.
2. Texturized Yarns: Resulting from processes that create bulking in filament yarns to enhance comfort, reducing pilling and improving insulation.

Yarn Count and Density

1. Counting Systems:

   • Various direct (e.g., denier, tex) and indirect (e.g., cotton system, worsted system) approaches, affecting yarn assessment and comparison.

2. Calculating Yarn Diameter:

   • Based on yarn counts, utilizing formulas to ascertain diameter based on specific volumes, facilitating analysis of fabric properties.

3. Twist in Yarns:

   • The angle of twist directly affects strength, compactness, and aesthetic properties.

In summary, considerations for woven fabric construction cover a broad range of factors including yarn characteristics, density, twist, finishing modifications, and the production of complex yarns. These elements collectively contribute to the performance characteristics and final appearance of textiles.