Introduction of fiber structure and design ,types and uses

Introduction of Fiber structure and design

Woven fabric: A woven cloth is formed by yarns, namely warp and weft, interlacing two sets of yarn. These yarns are interlaced with one another according to the type of wear on design. The warp and weft yarns are also called an end and Dicks respectively

Or

Woven fabric is the fabric that is formed by the interlacement of warp & weft threads

Classification of woven structures:

Woven structures are classified into the following categories:

1. Simple Structure:
   a.The ends and the picks intersect one another at right angles, and the cloth are respectively parallel with each other
   b.There is only one series of ends and one series of picks.
   c.All the constituent threads are equally responsible for the utility or performance of the fabric and the aspect of aesthetic appeal.}
   Example: Plain, Twill fabric.
2. Compound Structure:
   a.More than one series of ends and picks are used in this structure.
   b.Some of the threads may be responsible for the body of the fabric, while some may be employed entirely for ornamental purposes.
   c.In the clothes, some threads may be found not to be in parallel formation one to another in either plane.
   Example: Pile, Towel fabric.

Texture: The quality or properties which we get from fabric by interlacing of warp and weft yarn, such as handle properties, shinning properties, and draping properties.
The texture of woven fabric depends on-
a.Yarn (warp, weft) count
b.EPI, PPI
c.Yarn twist.
d.Characteristics of fiber.
e.Interlacement.

Methods of weave representation:

1. Warp overlap (warp above weft)
2. weft overlap (Weft above warp).

Feature of design:

• The vertical lines/ space is to represent a warp end
• The Horizontal space is to be represented to a weft pick.
• Each square indicates an intersection of an end and a pick.
• X represents warp up over weft. And Blank represents weft up over warp.
• There are two and only two possibilities of each crossing; either the end passes over the pick or the pick passes over the end.
• Only one repeat should be shown on the design paper.
• —Symbols indicate repeat units.
• # Represents starting point.

Formula Number: Formula number is a notation diagram that represents the warp and weft interlacing point. The system of expressing the fabric representation is called Formula Number.
The warp floats coming up are put above the fraction line, and the weft floats going down are put above the fraction line, and the weft floats going down are put under the fraction line.

There are two practical methods of wave representation.

  i) linear method;

→Warp yarn is represented by vertical lines.

→ Weft yarn is represented by vertical lines.

→ Warp up is marked by dot marks.

→ Time-consuming to represent.

ii)Canvas method:

1. Square paper/graph paper is employed.
2. Each vertical space represents a warp yarn.
3. Each horizontal space represents a weft yarn.
4. The warp up is shown by filling squares.

Weave repeat (Repeat size):

1. The repeat of weave is a quantitative expression of any given weave. It indicates the minimum number of warp and weft threads for a given weave.

Ex : For 1/1 design; repeat will be 2 * 2

        For 2/1 design;repeat will be 3*3

Classification of Parts of a complete design for a woven fabric:

1. Weave Plan.
2. Drafting Plan.
3. Lifting Plan.
4. Denting Plan.
5. Weave Plan: It represents the interlacement of warp and weft yarn. It shows the ups and downs of each yarn in a fabric sample it draws on graph paper. The warp face and weft face are identified by any symbol and blank space, respectively. The vertical spaces are the warp, and the horizontal is the weft.
6. Drafting Plan: The process of drawing the warp yarn into the heald eye according to the weave plan or design is called drafting, and the plan by which drafting is indicated is called the drafting plan. It indicates the no. of heald shafts required to make a design. It is drawn on the top of the weave plan. The vertical spaces are the warp, and the horizontal is healds.
7. Lifting plan: Lifting plan defines the selection of healds to be lifted or lowered on each successive insertion of weft or pick.
   A lifting plan is drawn at the right side of the weave plan.
8. Denting plan: The process of inserting warp yarn through a reed is called denting. The planning of this denting according to order is called a denting plan.
   Usually two yarns are passed through the dent.

Types of the Draft Plan:

1. straight draft:
   1. Drafting order progresses successively from first to last head frame
   1. No. of heald frame = No.of warp yarn repeat
   1. Lifting plan is the same as the weave plan
   1. Simplest & most commonly used draft
   1. Used in twill & satin design

• Pointed draft:

“This is similar to a straight draft. It is suitable for weaves such As pointed twill, diamond weaves, and common types of honeycombs. The consecutive draft is reversed after half the repeat warp way. The number of heald shafts is about half the repeat size of the weave.

1. Symmetric design
   1. Similar to a straight draft but reversed after half the repeat warp way
   1. ½ * No. of warp yarn repeat = No of heald frame
   1. Used in zigzag twill & diamond
   1. Broken draft :

A broken draft almost resembles a pointed draft. However, the pointed effect is broken. This type of draft is suitable for weave  like herringbone bone twills!”

1. It Almost resembles pointed draft, but a pointed draft, but the pointed effect is broken.
   1. Suitable to produce herringbone twills, diaper design, etc
   1. Skip draft :
      1. Use more heald frames than the minimum required for a weave
      1. Used to distribute the warp threads more uniformly and reduce the friction & rubbing between the ends.
      1. Suitable for weaving fabrics having heavy warp thread density.
      1. The heald frame are divided in two group.All even-number warp yarns are drawn through the second group of heald frames, and all odd-number warp yarns are drawn through the first group of heald frame .

The sateen draft serves the same purpose as the skip draft. A skip draft is normally employed for weaves such as, plain and twill up to a repeat of 4. Where as sateen draft is used for weaves having repeat size of more than 5 .

• Divided draft:
  • Heald frames are divided into two or more groups and a suitable type of draft is chosen for each group
  • Used for weaves having two series of warp threads (face & back warp)
  • Suitable to produce pile fabric, terry, double cloth, warp-backed cloth, etc.

• Grouped draft:
  • Used for producing a fabric with two different stripes
  • Suitable to produce check & stripe fabric
  • The number of shats in the draft depends upon the number of stripes and the repeat of the weave of each stripe.

• Curved draft:
  • Irregular & cannot be classified
  • Used for reducing the number of heald frames.
  • Suitable to produce fancy fabric.
  • Combined draft :

Various drawing methods can be combined in one draft to produce a certain type of fabric. Two or more drafts can be applied simultaneously. For example, straight and skip or sateen, grouped and curved, and so on  Combined draft is the most complicated and can be chosen only if there are some technological or economic reasons. The designer has a great experience and can do it properly.

1. Combination of different draft plans (Straight & skip, grouped & curved, etc)
   1.  Most complicated, so need a skilled designer
   1. Only use if any technological or economic reason occurs.

Warp(End) and Weft(pick/filling) yarn:

Warp and weft yarns have different demands placed on them and may differ in their structure or fiber type. Thus, a fabric may not have the same performance characteristics for warp and weft. The warp must withstand the loom’s high tensions and the weaving’s abrasion. so the warp yarns are stronger and more uniform with a higher twist. Filling yarns are more often fancy or unique function yarns, such as high-twist crepe yarns, low-twist napping yarns, or boucle yarns.

Identification of warp and weft yarns:

1. The selvage always nuns in the lengthwise (warp) direction of all fabrics.

2. Most fabrics have been elongated in the warp direction

3. Because of loom tension, The warp yarns lie straighter and more parallel in the fabric.

4. Fancy unique function yarns are in the filling direction.

5. fabric characteristics may differentiate between the warp and weft direction. For example, poplin has a weft rib, and satin has warp floats.

6. Warp yarns tend to be smaller, more uniform, and have a higher twist.

7. Fabric crimp is usually more significant for weft yarns.