Cotton Fibres Characteristics Consider For Spinning Process

1. Length
2. Strength
3. Fineness
4. Maturity
5. Cleanliness
6. Elongation.

Fibre length:

Fibre length is one of the most important fibre characteristics. 

It influences:

Spinning limit.

• Yarn strength.
• Yarn evenness.
• Handle of the product.
• Lusture of the product.
• Yarn hairiness.
• Productivity.

Different stable length of Cotton:

Short staple           —- 1 inch Or Less.

Medium stable      —- 1 1/32 inch to 1 1/8 inch.

Long stable            —- 1 5/32 inch to 1 3/8 inch.

Extra long stable   —- 1 13/32 inch to Above.

Fibre Fineness:

Fibre Fineness is one of the most important fibre characteristics. It determines how many fibre are present in the X-section of a yarn of given thickness.

Fineness is usually specified by the relation of mass (weight) to length (Km).

\Tex = mass/length

The Fineness scale is as follows:

MIC value                           Fineness

Up to 3.1                             Very fine

3.1 to 3.9                             Fine

4.0 to 4.9                             Medium

5.0 to 5.9                             Slightly Course

Above 6                                Course

 Strength:

The minimum strength for a textile fibre is approximately 6 CN/Tex. In relation to cotton the strength of fibre bundles is measured and stable as the pressley value.

\Pressley Index = Breaking strength in lbs / Bundle weight in gm.

Pressley Index                              Strength

93 – Above                                     Excellent

87 – 92                                            Very strong

81 – 86                                            Strong

75 – 80                                            Medium

70 – 74                                            Fair

Under 70                                        Weak

Maturity:

Fibre maturity means the thickness of cell wall. The more thickness, the maturity. Unripe fibres have neither adequate strength nor adequate longitudinal stiffness.

They therefore lead to:

• Loss of yarn strength.
• Nippiness.
• A high proportion of short fibres.
• Varying dye ability.
• Processing difficulties mainly at the card.

Elongation:

It is a very important factor for spinning. Without this fibre could not be spinned. Elongation of cotton fibre 6-10%.

 Cleanliness & Trash content:

Generally many types of foreign matter may contain in cotton stocks.

           Vegetable matter           Mineral matter              Other foreign matters

1. 1.Husk                               1. Soil                                 1. Metal fragments
2. 2.Seed                               2. Sand                               2. Cloth fragments
3. 3.Stem                               3. Dust                                3. Packing fragments
4. 4.Leaf fragments
5. 5.Wood fragments

As spinning process is sensitive to impurities. So the fibre should be main taired clean as far as possible. The reason for fibre containing such foreign matters are:

Modern high performance plucking system

• Hard ginning, cleaning & pre-drying
• Cleanliness, handling, during transportation & pack.

The scale below represents the degree of contamination:

Up to 1.2%        ———————   Very fine

1.2 to 2.0%        ———————     Clean

2.0 to 4.0%       ———————    Medium

4.0 to 7.0 %      ———————-     Dirty

7.0 to Above     ———————-  Very dirty

Effect of unclean fibre:

Additional stress on personal.

• Environment problem.
• Effect on the production.
• Stressing of the machine.

Brand Name                               Country

Pima, Arizona & SJV       ———–    USA

Eluna, Parvee & Ronda ———–    CIS

Giza                                   ———–    Egypt

Andy                                  ———–    Australia

Suvin                                 ———–    India

Delta                                 ————   Bangladesh

Barakat                             ————   Sudan

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