Textile Yarns and Threads

Textile Yarns and Threads

Yarn is a long continuous length of interlocked fibres, suitable for use in the production

of textiles, sewing, crocheting, knitting, weaving, embroidery, and rope making.

Thread is a type of yarn intended for sewing by hand or machine.

Yarns can be described as single or one-ply; ply, plied, or folded; or as cord, including

cable and hawser types.

Single yarns

Single, or one-ply, yarns are single strands composed of fibers held together by at

least a small amount of twist; or of filaments grouped together either with or without

twist; or of narrow strips of material

Single yarns of the spun type, composed of many short fibres, require twist to hold

them together and may be made with either S-twist or Z-twist. Single yarns are used

to make the greatest variety of fabrics.

Ply yarns:

Ply, plied, or folded, yarns are composed of two or more single yarns twisted together.

Two-ply yarn, for example, is composed of two single strands; three-ply yarn is 

composed of three single strands. 

In making ply yarns from spun strands, the individual strands are usually each twisted

in one direction and are then combined and twisted in the opposite direction. When 

both the single strands and the final ply yarns are twisted in the same direction, the

fibre is firmer, producing harder texture and reducing flexibility. Ply yarns provide

strength for heavy industrial fabrics and are also used for delicate-looking sheer 

fabrics.

Cord yarns:

Cord yarns are produced by twisting ply yarns together, with the final twist usually

applied in the opposite direction of the ply twist. 

Cable cords may follow an SZS form, with S-twisted singles made into Z-twisted plies

that are then combined with an S-twist, or may follow a ZSZ form. Hawser cord may 

follow an SSZ or a ZZS pattern. Cord yarns may be used as rope or twine, may be

made into very heavy industrial fabrics, or may be composed of extremely fine fibres 

that are made up into sheer dress fabrics.

Novelty yarns:

Novelty yarns include a wide variety of yarns made with such special effects as slubs,

produced by intentionally including small lumps in the yarn structure, and man-made 

yarns with varying thickness introduced during production.  

Textile Yarn Faults

Article by RESIL

What are Yarn Faults?

Yarn quality is influenced by various types of yarn faults that also affect the quality of fabric

produced. During the yarn manufacturing process various types of irregularities are generated

in the yarn diameter regularly or at intervals, commonly known as yarn faults. These faults are

categorized as below:

1. Frequently Occurring Faults( Analyzed by Uster Evenness Tester)

2. Seldom Occurring Faults( Scanned by Uster Classimat Tester)

Frequently Occurring Faults:

  

• Thick Places

• Thin Places

• Neps

Thin places and thick places are produced due to drafting irregularities and neps are generated due toimmature fibers in raw material.

Why to avoid yarn faults:

• Causes breaks during post spinning operations.

• Reduces aesthetic appeal of the fabric, if allowed to pass.

Objectionable yarn faults can be categorized in three groups:

1. Faults due to raw material

2. Faults due to piecing

3. Faults due to Spinning machine

 

Calendering Process :- A Technical article By RESIL TEAM

Calendering Process :- A  Technical article By RESIL TEAM

What is Calendering Process?

Calendaring is the process of smoothing and compressing a textile material by passing a single

continuous sheet of fabric through a number of pairs of heated rolls.

The rolls in combination are called calenders. Calender rolls are constructed of steel with a

hardened surface, or steel covered with fiber.

Purpose of doing Calendering Process for textiles:

The fabric is then run through rollers that polish the surface and make the fabric smoother and

more lustrous. Due to High temperatures and pressure the Fabrics that go through the

calendering process feel thin, glossy and papery.

Types of calandering Machine:

Nipco-Flex Calender:

The pressure application concept of this calender is different from the conventional

calendering system.

The pressing roller consists of a rotating shell that is covered with a highly elastic plastic

material named as RACOLAN.

The roller has fixed axels on which hydrostatic support elements are mounted that press the

racolan shell against either steel or a cotton/paper roller.

The hydrostatic pressure is applied with oil and is adjustable according to width of the cloth.

The NIPCO roller can be arranged in vertical position or in L shape with a hot steel roller at top

and a cotton bowl in front of it.

The main advantages of NIPCO calender over a conventional calender are;

1. Attainment of very high pressure.

2. Adjustment of pressure line according to width of cloth.

3. No over load at the fabric selvedge.

4. Easy installation and removal of the rollers.

Felt Calender:

Felt calenders are mainly used for imparting lustre and smoothness to silk, rayon and cotton

knitwear materials.

These work at low pressure and temperature than used for cotton.

The cloth is pressed between an endless felt blanket and a hot steel cylinder at a speed of 20 to 40 meters/minutes

Dyeing without water

Textile dying and treatment processes produce 17 to 20 percent of industrial water pollution in the world. 72 toxic chemicals, 30 of which cannot be removed, have been found in our water solely from textile dyeing. As a vital part of textile production, the dyeing processes cause a large problem for designers who are trying to be more environmentally conscious.

 AirDye® technology is a water free dyeing and printing process. AirDye technology has been produced by AirDye Solutions, formerly Colorep Inc., and is a technology development and textile design company. On their website AirDye Solutions describe themselves as, “passionate about creating new printing and dyeing technologies that improve quality, value, and accessibility while helping to sustain the planet.”
AirDye technology uses a one-step process, where the liquid state of dye is eliminated altogether. The process starts with heating fabric and simultaneously dye is injected into the fibers in the form of gas. “The entire process is waste-free: the paper is recycled, and used dyes and toners are also recycled to make tar and asphalt.” One downfall is that only synthetic textiles can be dyed using AirDye, as the physics of the technology do not work with natural fibers such as cotton.
Up to 95% of the water, 86% of the energy and 84% of the green house gases can be saved using AieDye as compared to conventional print and dye methods. Up to 45 gallons of water can be saved in the production of just one garment. The dying of synthetic fabrics alone uses 2.4 trillion gallons of water, every year, and with an unknown/untold amount of environmental damage.
AirDye technology creates a large opportunity for regions around the globe that cannot obtain water as easily, to localize textile production. 
As AirDye technology improves, more water/energy will be saved and hopefully the mass market of textile production could be ready for a monumental change.

AirDye® Technology