Plain Weave structure

What is Plain weave?

A weave obtained by lifting the even no. warps at one pick & the odd no. of warps in the next pick. And the repeat contains 2 ends & 2 picks. Both sides of the weave are identical (1/1).

Write the characteristics of plain weave

- Both sides of the weave are identical

- Threads interlacing in alternate order

- The repeat contains two ends and two picks.

- The texture is stronger and firmer than any other ordinary cloth.

- It comprises a high production of the total output of woven fabrics.

- Each thread gives the maximum amount of support to the adjacent threads.

Weave, Drafting, Lifting and Denting Plan | Weaving

What is Weave plan?

It illustrates the interlacing of ends and picks in the fabric under consideration. In the weave plan, space between two vertical lines indicates as warp yarn and the space between two horizontal lines indicates as weft yarn.

What do you mean by drafting or looming plan?

A draft indicates the number of healds used to produce a definite design and the order in which the warp threads or ends are threaded through the mail eye of the healds. In the drafting plan, space between two vertical lines indicates as warp and space between two horizontal lines indicate as heald shaft.

Formula number vs Repeat number

Formula Number

• It is a kind of shorthand expression of the waving of warp and weft yarn.
• It gives the information of successive floats.
• The warp floats coming up are put above the fraction line and the weft floats are put under the fraction line.

Repeat number

• It indicates the number of warp and weft yarns in the repeat.
• The repeat number for the warp equals the sum of the figures in the formula number. And for the weft vice versa.
• For example 1/1 plain weave repeat: 2x2

How can we identify warp and weft in a fabric?

Warp & Weft:

The lengthwise or longitudinal yarn of fabric is termed as the warp yarn, while the width-wise or transverse yarn is called the weft or fill yarn.

Identification of warp and weft:

• The selvedge always runs in the lengthwise (warp) direction of all fabrics.

• Most fabrics have lower elongation in the warp direction.

• The warp yarns lie straighter and are more parallel in the fabric because of loom tension.

• Fancy or special function yarns are usually in the filling direction.

• Warp yarns tend to be smaller, are more uniform in structure and appearance and have a higher twist.

• Fabric crimp is usually greater for weft yarns.

• Fabric characteristics may differentiate between the warp and weft directions. For example, denim has a warp face and satin has warp floats and poplin has a weft rib.

Comprehensive Viva Preparation | Fabric Engineering

Comprehensive Viva Preparation | Fabric Production Techniques

Comprehensive Viva Preparation | Loom Motion

Effect of Fabric Structure on Fabric Properties

Comparison between Knitted and Woven Fabrics

Knitting is a method of producing the fabrics, where yarns are interlooped to form a flat fabric. Two types of knitting exist, namely, warp knitting and weft knitting whereas, weaving is another method to produce fabrics by the right angle interlacement of 2 sets of yarn –named as warp [longitudinal direction or length-wise direction] and weft [transverse direction or width-wise direction]. The prominent differences between the knitted and woven fabrics, machine and manufacturing process are mentioned below.

How to cut sample from knit and woven fabric?

Fabric samples from warp and weft are taken separately as their properties vary substantially along warp and weft. Identify and mark the warp direction first. Make sure that no two specimens contain the same warp or weft threads. Mark and cut samples at least 2 inches away from the selvedge. Also, make sure not to take samples from creased, wrinkled or damaged portions of the fabric, if any. In the case of knit fabric, samples are taken from different parts of the fabric almost the same way as done for wovens.

Interlock Circular Knitting | Features

Emdadul Haq

Lecturer

Department of Textile Engineering, Primeasia University; Bangladesh

Features of Interlock Knitting ( Machine, Process and Structure)

1. Machine has two beds, machine may be flat or circular but generally circular.

2. There are two subsets of needles in each bed, the subsets re known as short and long needles respectively.

3. Two sets of cam system, i.e. cam path in each bed accommodate short and long needles in the other bed and vice-versa.

4. Short needles in one bed make loops in conjunction with short needles in the other bed. Similarly, long needles in one bed make loops in conjunction with long needles in the other bed.

Interlock fabric structure

7-Wheel Take-Up Mechanism

Emdadul Haq 

Lecturer, Department of Textile Engineering, Primeasia University; Bangladesh  

Take-up is the secondary motion of the loom. The process of withdrawing fabric from the weaving zone at a constant rate and then winding the cloth on the cloth roller as the weaving proceeds is called take-up.

Figure: 7-wheel take-up mechanism

Construction of Tappet Shedding Cam

Emdadul Haq

Lecturer, Department of Textile Engineering, Primeasia University; Bangladesh

Construction of Tappet Shedding Cam for Plain weave (1/1) using the following parameters:

1. Weave design of the fabric: Plain (1/1)

2. The minimum distance between Cam and Follower or Treadle bowl centre = 3 inch

3. The diameter of Follower or Treadle bowl = 2 inch

4. Lift of the Tappet = 5 inch

5. Dwell Period = 1/3 of a pick
6. Movement pattern during rising and fall: Simple Harmonic Motion (SHM)

Tappet Shedding Cam Construction for Plain Weave

Purl Circular Knitting | Features

Emdadul Haq

Lecturer

Department of Textile Engineering, Primeasia University; Bangladesh

Features of Purl Knitting ( Machine, Process and Structure): 

1. Machine has two beds. Machine may be flat or circular.

2. There is only one set of needles which change the bed in alternatively knitting cycle.

3. Needles are of a special type; generally double hooked latch needles are used.

4. Needles are shifted from one bed to another bed with the help of sliders. Two sliders are needed for each needle.

5. Same needle makes face loop in one bed a back loop in other bed.

Purl structure and necessary elements

Rib Circular Knitting | Features

Emdadul Haq

Lecturer

Department of Textile Engineering, Primeasia University; Bangladesh

Features of Rib Knitting ( Machine, Process and Structure)

1. Machine has two beds- may be flat or circular.

2. There are two sets of needles- one in each bed.

3. There are two cam systems- one in each bed.

4. Needles in the two beds are not face to face but needles in one bed are in between the needles of the other bed so that they do not touch while raised for clearing.

Rib Circular Knitting Machine

Plain or Single Jersey Circular Knitting | Features

Emdadul Haq

Lecturer

Department of Textile Engineering, Primeasia University; Bangladesh

Features of Plain or Single Jersey Knitting ( machine, process and structure):

1. The machine has only one bed which may be flat or circular.

2. There is only one set of needles and one cam system in the machine.

3. Minimum one yarn is needed to produce a fabric.

4. Single faced structure, i.e. only one type of loops- face or back are visible on the surface.

5. Loops are V-shaped on the technical face and semi-circular on technical back of the fabric.

6. Because of side limbs of the loops on the face side, it feels smoother on the face side than the backside.

Single Jersey Circular Knitting Machine

Spacer fabric | Advantages | Applications

Md. Emdad Sarker
Assistant Professor
Department of Fabric Engineering, BUTEX

Unlike two-dimensional woven, knitted, and crocheted fabrics, spacer fabrics consist of the top and bottom layers of fabric, connected with filament yarns similar to a corrugated box (three-dimensional structure). It is believed that this single layer regime would create substantial savings both in treatment time and financially, as it is intended to replace the current multilayer bandage systems. Currently, the most economical system available is a two-layer system incorporating a padding and compression bandage. 

The knitted three-dimensional spacer fabrics themselves can be made by using either warp knitting or weft knitting technologies. The basic structure of the weft-knitted spacer fabric is limited to either knitting the spacer threads on the dial and tucking on the cylinder or tucking the spacer threads on the dial and cylinder needles [1]. 

Spacer fabrics with a closed and open structure

Technical Knitting | Applications of Technical Fabric Structures

Md. Emdad Sarker
Assistant Professor
Department of Fabric Engineering, BUTEX 

Technical knitting is an advanced capability which allows textile components to be used in the technical field rather than traditional textiles. Technical knitting is an exciting capability, making it possible to create ground-breaking textile structures, constructions and textures as fully fashioned textile components which just can’t be achieved in flat-weaving [1]. In this article, some technical knitted fabrics along with their applications have been described.

Applications of Technical Knitted Fabrics

1. Bandages 

Bandages are designed to perform a whole variety of specific functions depending upon the final medical requirement. The most common application for bandages is to hold dressings in place over wounds. Such bandages include lightweight knitted or simple open weave fabrics made from cotton or viscose that are cut into strips then scoured, bleached, and sterilised. Elasticated yarns are incorporated into the fabric structure to impart support and conforming characteristics. Knitted bandages can be produced in tubular form in varying diameters on either warp or weft knitting machines. Compression bandages are used for the treatment and prevention of deep vein thrombosis (DVT), leg ulceration, and varicose veins and are designed to exert a required amount of compression on the leg when applied at a constant tension [2].

Figure-1 Tubular bandage

Knitting | Technical Knitting

Md. Emdad Sarker
Assistant Professor
Department of Fabric Engineering, BUTEX

Knitting is another method of fabric production, where yarns are interlooped to form a flat fabric. Two types of knitting exist, namely, warp knitting and weft knitting.

Weft knitting is the most common method in use, after weaving, because of its versatility and Weft-knitting technology also offers considerable advantages in terms of cost, flexibility, and versatility as compared to weaving technique in the production of suitable structures for a contourable protective material. This, however, has not been proven successful, mostly because of the low initial modulus of a knitted fabric, which is due to the high degree of interlocking of the yarns. Since the fabric is formed by interlocking of the yarns, the yarns are flexible and are free to move within and out of the loops, and thus stretch when a load is applied, resulting in low initial modulus, low capital and low floor costs. A weft-knitted fabric can be produced using one single strand of yarn Figure-1(a). while a warp-knitted fabric or a woven fabric requires the same number of yarns as required through the width of the fabric Figure-1(b).

Figure-1: Representation of knitted structure (a) weft-knitted structure; (b) warp-knitted structure [1]

Quality parameters of fabric

Fabric length

Fabric length is measured without conditioning and after conditioning of 24 hours. If length difference is found less than 0.25 percent, then the second result is taken as sample length. If the difference is found more than 0.25 percent, then the sample is kept conditioned again for 24 hours and checked the difference in length. The process repeats until length difference achieved less than 0.25 percent. When the accurate length is found, a correction is made for the full length of fabric to calculate the accurate length of bulk.